Current concepts in teaching and learning in surgery

Modern surgical teaching is evolving at speed. The environment in which we learn and teach is subject to a number of extrinsic pressures. These are influencing ways in which medical students and trainees learn and are taught the discipline of surgery. As a surgical educator it is useful to understand the reasons for these changes and to acquire the skills necessary to provide effective teaching. This short article looks at reasons why one would wish to develop surgical teaching skills, covers basic principles associated with delivery of effective teaching sessions and briefly reviews other avenues that may enhance teaching practice.     

Hyperacuity thresholds for oscillatory movement are abnormal in strabismic and anisometropic amblyopes.

The hyperacuity performance of amblyopic individuals is known to be abnormal, particularly on vernier tasks. Oscillatory movement displacement thresholds (OMDT's) a form of hyperacuity, were investigated over a range of temporal frequencies (1, 4, 7, 10, and 13 Hz) in 8 normal controls, 5 strabismic amblyopes, and 4 anisometropic amblyopes to see if this form of hyperacuity was also affected by amblyopia. OMDT's were found to be significantly raised in all of the strabismic amblyopes and three of the four anisometropes over all temporal frequencies investigated when compared to the control group. In the fourth anisometrope, OMDT's were raised at low temporal frequencies only. The findings are interpreted as evidence that magnocellular and parvocellular channels are affected in the amblyopic visual system. The functional loss in amblyopia cannot be described completely unless both temporal and spatial thresholds are investigated.     

Transition from pre-linguistic to linguistic communication in hearing-impaired infants

This paper examines the development of the ability to signal intentionality in hearing-impaired infants. Four infants were monitored from the time aids were accepted and worn consistently until an expressive vocabulary of ten words was recorded. The focus of the study was the child's developing ability to coordinate attention to both a person and an object. Longitudinal video-taping allowed analysis of the stages and rate at which these infants achieved this pattern of attention. These infants were found to follow a sequence of steps similar to that reported in studies of hearing children. This finding and its possible implications for early identification of hearing impairment are discussed.     

Optical Radar Detection of Precancerous Bronchial Tissue

. Previous measurement of laser-induced fluorescence in bronchus tissue is simulated using an electromagnetic (EM) scattering model. The EM parameters derived indicate that the changes in the thickness of the epithelium associated with carcinoma in situ can be detected using an optical radar process, providing an early detection of cancer. Further simulation using the EM model indicates various practical methods of measuring the thickness, including frequency modulated continuous wave optical radar, multilaser continuous wave radar and low coherence interferometry. Initial optical experiments and calculations have demonstrated which of the methods is likely to lead to the development of an endoscopic instrument. The availability of suitable optical components is a major consideration. Some early interferometry results indicate that a resolution of at least 40 μm and a signal to noise of up to 45 dB can be readily reached for histological imaging. Paper received 12 July 1999; accepted after revision 26 January 2000.     

The complete genome sequence of PM2, the first lipid-containing bacterial virus To Be isolated.

Bacteriophage PM2 was isolated from the Pacific Ocean off the coast of Chile in the late 1960s. It was a new virus type, later classified as Corticoviridae, and also the first bacterial virus for which it was demonstrated that lipids are part of the virion structure. Here we report the determination and analysis of the 10, 079-bp circular dsDNA genome sequence. Noteworthy discoveries are the replication initiation system, which is related to the rolling circle mechanism described for phages such as φX174 and P2, and a 1.2-kb sequence that is similar to the maintenance region of a plasmid found in a marine Pseudoalteromonas sp. strain A28.     

The effects of doxapram on breathing, heart rate and blood pressure in fetal lambs

In experiments to assess its value in the study of fetal arterial chemoreceptor reflexes, doxapram (0.5 - 2 mg i.a.) given to unanaesthetized fetal lambs in utero in low voltage electrocortical activity stimulated fetal breathing in 73% of trials. The response began within a few seconds and lasted up to 5 min. This response to doxapram was present in intact or mid-collicular brainstem transected fetuses and after bilateral section of the carotid sinus nerves and cervical vagosympathetic trunks (denervation). In intact and brainstem transected fetuses, doxapram injections were followed by a modest rise in arterial pressure and a small fall in heart rate. After denervation the rise in arterial pressure was fourfold and the heart rate increased. Electrocortical activity and limb movements were not affected in any group of lambs, and fetal breathing was not induced during isocapnic hypoxia. It is concluded that doxapram stimulates fetal breathing by a central action below the pons, and that it can therefore not be used to study peripheral arterial chemoreceptor function in utero.     

Novel Rho kinase inhibitors with anti-inflammatory and vasodilatory activities

Increased Rho kinase (ROCK) activity contributes to smooth muscle contraction and regulates blood pressure homeostasis. We hypothesized that potent and selective ROCK inhibitors with novel structural motifs would help elucidate the functional role of ROCK and further explore the therapeutic potential of ROCK inhibition for hypertension. In this article, we characterized two aminofurazan-based inhibitors, GSK269962A [N-(3-{[2-(4-amino-1,2,5-oxadiazol-3-yl)-1-ethyl-1H-imidazo[4, 5-c]pyridin-6-yl]oxy}phenyl)-4-{[2-(4-morpholinyl)ethyl]-oxy}benzamide] and SB-7720770-B [4-(7-{[(3S)-3-amino-1-pyrrolidinyl]carbonyl}-1-ethyl-1H-imidazo[4,5-c]pyridin-2-yl)-1,2,5-oxadiazol-3-amine], as members of a novel class of compounds that potently inhibit ROCK enzymatic activity. GSK269962A and SB-772077-B have IC50 values of 1.6 and 5.6 nM toward recombinant human ROCK1, respectively. GSK269962A also exhibited more than 30-fold selectivity against a panel of serine/threonine kinases. In lipopolysaccharide-stimulated monocytes, these inhibitors blocked the generation of inflammatory cytokines, such as interleukin-6 and tumor necrosis factor-alpha. Furthermore, both SB-772077-B and GSK269962A induced vasorelaxation in preconstricted rat aorta with an IC50 of 39 and 35 nM, respectively. Oral administration of either GSK269962A or SB-772077-B produced a profound dose-dependent reduction of systemic blood pressure in spontaneously hypertensive rats. At doses of 1, 3, and 30 mg/kg, both compounds induced a reduction in blood pressure of approximately 10, 20, and 50 mm Hg. In addition, administration of SB-772077-B also dramatically lowered blood pressure in DOCA salt-induced hypertensive rats. SB-772077-B and GSK269962A represent a novel class of ROCK inhibitors that have profound effects in the vasculature and may enable us to further evaluate the potential beneficial effects of ROCK inhibition in animal models of cardiovascular as well as other chronic diseases.