Cecilia Brassett

Kinetics of dissociation of nogalamycin from DNA: comparison with other anthracycline antibiotics

Stopped-flow spectrometry and simple mixing techniques have been employed to investigate the detergent-induced dissociation of anthracycline antibiotics from natural and synthetic DNAs. Both daunomycin and nogalamycin dissociate more slowly from poly(dG-dC) than from poly(dA-dT) but the difference is much more marked for nogalamycin. With an equimolar mixture of poly(dG-dC) and poly(dA-dT), or with poly(dA-dC).poly(dG-dT), dissociation of nogalamycin occurs very slowly. In all cases the release of antibiotic from a synthetic polynucleotide is a one-step process following a single exponential. Dissociation of daunomycin, adriamycin and iremycin from calf thymus DNA is a more complex reaction which requires a two-exponential fit, in contrast to earlier reports, but differences between the behaviour of the three antibiotics are minor. Dissociation of nogalamycin from natural DNA requires a three-exponential fit, is in general far slower, and depends upon the base composition, the level of binding and the time allowed for the complex to equilibrate. It is concluded that sequence selectivity is minimal or lacking for daunomycin, whereas nogalamycin binding is sequence dependent and probably involves migration of the antibiotic between DNA binding sites. There is an inverse correlation between dissociation rate constants and antibacterial potency in simple tests.

Segmental colonic length and mobility

INTRODUCTIONnLocoregional variation in the human colon is important in surgical practice; the length and mobility of different colonic regions impacts on laparoscopic and endoscopic colorectal procedures. The aim of this study was to refine anatomical understanding of the colon in terms of segmental length and mobility.nnnMETHODSnThe colons of 35 cadavers were examined to determine lengths of caecum as well as ascending, transverse, descending and rectosigmoid colon, and to characterise colonic mobility at each location in terms of the mesenteric attachments. The presence of Jacksons membrane (a congenital peritoneal band of the right colon) was also documented.nnnRESULTSnThe mean total colonic length was 131.2cm (standard deviation [SD]: 13.4cm). There was no correlation with height, age or sex; the best predictor of total colonic length was the length of the rectosigmoid segment. The mean height of the transverse mesocolon was 7.4cm (SD: 3.6cm) and that of the sigmoid mesocolon was 6.3cm (SD: 2.6cm). Two-thirds of the subjects had a mobile portion of the ascending colon and nearly one-third had a mobile descending colon. A mobile ascending colon was significantly more common in females. Jacksons membrane was present in 66% of the subjects.nnnCONCLUSIONSnThis cadaveric study suggests that rectosigmoid length accounts for most of the variability in total colonic length. The significant proportion of colons with mobility of the ascending and descending segments prompts revision of the traditional anatomical teaching of these segments as fixed and retroperitoneal. Mobility of the ascending colon may account for the anecdotal finding that colonoscopy is more challenging in female patients. Jacksons membrane was identified in most colons.

Diachronic and synchronic overview of the Tujia language of Central South China

Abstract The Tujia language, which belongs to the Tibeto-Burman branch of the Sino-Tibetan language family, is spoken by members of the Tujia ethnic minority who live in the border regions of Hunan, Hubei and Guizhou Provinces and Chongqing Municipality in the People’s Republic of China. Although the Tujia people number over eight million, there are now only around 70,000 speakers, that is, less than 1% of the Tujia population. This article first traces and discusses the reasons for the historical decline in the use of Tujia, and then investigates contemporary factors which affect language attitudes and use. The linguistic interactions between Tujia and Chinese are also described, together with the resulting phonological, lexical, and grammatical changes. The article concludes that, in its present endangered state, the Tujia language is likely to disappear completely within a few generations.

Exercise serpent anatomy: cadaveric trauma simulation training to improve the resilience of reservist combat medical technicians

We recently provided training in the Human Dissection Room at the University of Cambridge for reservist combat medical technicians (CMTs) with a particular emphasis on improving their resilience when exposed to battlefield trauma.nnReservist medical units include individuals who receive training as

'Can you be a doctor, even if you faint?' The tacit lessons of cadaveric dissection

BACKGROUNDnThe undergraduate Medicine course at the University of Cambridge has included cadaveric dissection as part of its anatomy teaching for over three centuries. In recent years, medical schools in the UK and the US have debated whether cadaveric dissection is a useful and efficient way of teaching anatomy. Existing research on this subject has focused narrowly on the knowledge-acquisition for medical students afforded through dissection, and thus we have broadened the scope of such considerations to include the emotional responses of medical students to the dissection process.nnnSUBJECTS AND METHODSnThe basis for this paper is a phenomenological analysis of response data gathered from 56 first year medical students at the University of Cambridge through written questionnaires and discussion groups before and after their first experiences of cadaveric dissection.nnnRESULTSnOur research suggests that there are in fact many more lessons taught and acquired through studying in the dissection room: they are tacit, emotional, experiential and dispositional.nnnCONCLUSIONSnWhen this wider picture of the value of dissection is considered, a much stronger case for the continued inclusion of cadaveric dissection in the medical curriculum can be made, as it is a valuable and unique educational experience.

Neurovascular Anatomy at the “Box Junction”: Considerations in the Anterolateral Thigh Flap

Background The anterolateral thigh (ALT) perforator flap is one of the most widely used flaps in reconstructive microsurgery. This study investigated a previously unexplored and clinically relevant aspect of perforator anatomy: the “box junction” (BxJn), the point at which the perforator arises from its source vessel. Negotiating the BxJn can be a challenging and time‐consuming step in flap harvest, due to the neurovascular structures in the area which must be protected from injury. However, as the presence and location of these structures have yet to be clearly defined, painstaking exploration is necessary on each occasion. Knowledge of BxJn anatomy could allow surgeons to harvest the ALT flap more rapidly and safely. Methods We dissected 20 cadaveric thighs and identified perforators to the ALT region and investigated the neurovascular anatomy at their BxJns. Results In 51 BxJns, two clinically relevant vascular structures were identified: an intramuscular artery arising from the perforator (23, 45% of cases) and a “deep” artery to the underlying muscle arising from the source vessel (29, 57% of cases). We confirmed the consistent presence of motor nerve branches and describe one previously unreported, clinically significant variation, in which the nerve to vastus lateralis crosses the BxJn (12, 24% of cases); 36, 71% of BxJns contained at least one vascular and one neural structure. Conclusion Our study confirms that the BxJn is a site of potentially complex and challenging neurovascular anatomy for the surgeon. Based on these results, we propose an algorithm to guide inexperienced surgeons in negotiating this area.

Difference in real-time magnetic image analysis of colonic looping patterns between males and females undergoing diagnostic colonoscopy

n Background and study aim u2002Magnetic imaging technology is of proven benefit to trainees in colonoscopy, but few studies have examined its benefits in experienced hands. There is evidence that colonoscopy is more difficult in women. We set out to investigate (i) associations between the looping configurations in the proximal and distal colon and (ii) differences in the looping prevalence between the sexes. We have examined their significance in terms of segmental intubation times and position changes required for the completion of colonoscopy. Patients and methods u2002We analyzed 103 consecutive synchronized luminal and magnetic image videos of diagnostic colonoscopies with normal anatomy undertaken by a single experienced operator. Results u2002Deep transverse loops and sigmoid N-loops were more common in females. A deep transverse loop was more likely to be present if a sigmoid alpha-loop or N-loop had formed previously. Patients with sigmoid N-loops were turned more frequently from left lateral to supine before the sigmoid-descending junction was reached, but there was no statistical correlation between completion time and looping pattern. Conclusions u2002This study has reexamined the prevalence of the common looping patterns encountered during colonoscopy and has identified differences between the sexes. This finding may offer an explanation as to why colonoscopy has been shown to be more difficult in females. Although a deep transverse loop following a resolved sigmoid alpha-loop was the most commonly encountered pattern, no statistical correlation between completion time and looping pattern could be shown. It is the first study to examine segmental completion times using a magnetic imager in expert hands.n

The role of radiology in anatomy teaching in UK medical schools: a national survey

AIMSnTo investigate the current use of radiology in anatomy teaching across the UK, and to determine the level of interest expressed in expanding its role in medical education.nnnMATERIALS AND METHODSnA 22-question electronic survey was distributed to the organisers of anatomy teaching at 35 UK medical schools. The questionnaire explored the use of radiology in their anatomy course, the different kinds of available resources, and attitudes towards integrating radiology into anatomy teaching.nnnRESULTSnResponses were received from 29/35 (83%) medical schools. Among the respondents, radiological anatomy featured in all but one of their curricula. Of those schools using radiology to aid anatomy teaching, 20/28 expressed a wish for more radiology in the curriculum. Timetabling constraints constituted one of the main difficulties in further implementation. In addition, 22/28 medical schools had already fostered collaborative links with local radiology departments, with 18 of these expressing a wish for further cooperation. Of the remaining six schools without current collaboration, four would like to establish connections.nnnCONCLUSIONnCompared with previous studies, this national survey shows a definite increase in radiological anatomy in medical school curricula with a stronger presence of radiologists in anatomy teaching. Despite this, most anatomy departments still express a desire to increase the radiological component in their courses.

Observations on the inconsistency of dermatome maps and its effect on knowledge and confidence in clinical students: Dermatomes in Medical Education

Dermatomes are an important component of medical curricula and clinical practice. In addition to the intrinsic complexity of dermatome maps, their discrepancies in the literature make their learning among students even more difficult. These discrepancies are particularly evident in the lower deltoid (“regimental badge” area) and upper back. The aims of our study were firstly to identify and compare published versions of the dermatome map focusing on depictions of the “regimental badge” area and upper back, secondly to assess the perceived confidence and knowledge of dermatomes among medical students, and finally to create and introduce a simplified dermatome map. For the first part of the study, depictions of dermatome maps that included the “regimental badge” area and upper back in webpages and books were compared. For the second part, a dermatome exercise was given to 177 medical students who were asked to draw and label the dermatomes on blank figures. A total of 45 sources depicting dermatomes of the “regimental badge” area and upper back were included in the study and showed significant discrepancies in both areas. In the dermatome exercise, the mean perceived confidence was 3.64u2009±u20091.58 (scale 1–10). Based on our pre‐set assessment criteria, upper limb, lower limb, nipple, umbilicus, and perineum dermatomes were labeled correctly by 57.1%, 43.5%, 52.6%, 60%, and 75.7% students, respectively. In light of our results, we propose a map of autonomous regions of clinically relevant dermatomes that can be used instead of whole dermatome maps for teaching purposes. Clin. Anat. 31:293–300, 2018.

Study of anatomical variance of the zygomaticofacial foramen and determination of reliable reference points for surgery

Dissection onto the facial aspect of the zygoma is common in procedures of the midface for traumatic injury, craniofacial deformity and cosmesis. These procedures carry risk of injury to the neurovascular structures exiting the zygomaticofacial foramen (ZFF). The purpose of the current study was to map the ZFF, and to determine reliable reference points from which to identify the ZFF pre- and peri-operatively. Secondarily, we aimed to compare ZFF anatomy between sexes and geographical populations. 429 adult skulls from 9 geographic locations were used in the study. A cross-line laser was superimposed onto each zygoma to generate consistent landmarks (lines 1 and 2) from which to measure the ZFF, and the number of ZFF on each zygoma was documented. The location and frequency of ZFF differed significantly between geographic populations, but not between sexes. Of all 858 sides, 0 foramina were found in 16.3%, 1 foramen in 49.8%, 2 foramina in 29%, 3 foramina in 3.4% and 4 foramina in 1.4%. 93% of foramina were found within a 25mm diameter zone (ZFF zone) centred at 5mm anterior to the intersection of lines 1 and 2 on the right zygoma, and 94% were found within equivalent measurements on the left. Using these landmarks, we propose a novel method of identifying a ZFF zone irrespective of sex or geographic population. This technique may be of use in preventing iatrogenic damage to the ZFF neurovascular bundle during procedures of the midface and in local nerve block procedures.