A modified technique to process peripheral nerves for light microscopy

A new technique is described to fix, paraffin embed and cut routine peripheral nerve biopsies for light microscopy. Buffered glutaraldehyde pH 7.4 is used as a common fixative for both light and electron microscopy. The nerve bits for LM are embedded in paraffin using the 'reverse embedding' method and blocks are trimmed to cut sections on the ultra microtome using glass knives. The uniformly thin sections can be utilised for any special stain and the good resolution of these thin sections facilitates better observation and documentation.     

基于Sihler’s技术的踝和足背皮神经的整体分布模式研究

目的 揭示踝及足背皮神经的整体分布模式,为皮瓣移植感觉重建提供形态学指导。 方法 成年尸体24具,紧贴肌表面摘取含皮下脂肪的踝及足背皮肤,用改良的Sihler’s染色法显示并观察皮神经整体分布模式。 结果 在Sihler’s染色的标本中,肉眼可见隐神经支配踝前区（40.01±7.6）%、踝后区（30±6.7）%、以及部分足背内侧缘。腓浅神经支配踝前区（60.03±6.8）%,其足背内侧皮神经支配足背内侧区、第1、2趾背及第3趾背内侧半;95.83%的足背中间皮神经分布到第3趾背外侧半、第4、5趾背。腓肠神经支配踝后区（70±5.3）%,其足背外侧皮神经支配足背外侧缘皮肤。腓深神经分布到第1、2趾背相对面。初级神经支密度以踝前区最高,次级及以下神经支密度和总的神经支密度均以足背内侧区最高。 结论 在踝或足背的皮瓣移植中,建议把踝前区或足背内侧区设计为利于感觉重建的首选供区或感觉需求较高的受区。     

Sihler’s神经染色法再改良在中空器官中的应用

目的探讨Sihler’s肌内神经染色法再改良在中腔器官染色中的应用。方法使用再改良的Sihler’s肌内神经染色法整体染色人的食管、胃、膀胱。结果各器官染色后,不需要剪开器官,支配食管、胃、膀胱的神经在器官壁内清晰可见,神经的分支以及分支间的联系可见。结论 Sihler’s肌内神经染色法不仅适用于骨骼肌肌内神经染色,也适用于平滑肌,只要处理得当较大的器官不剪开的情况下也适用。     

A modified KOH-collagenase method applied to scanning electron microscopic observations of peripheral nerves

Certain parts of the peripheral nervous system were observed by a modification of the KOH-collagenase method by Miller et al. (1982). The sciatic nerve of the mouse, and dorsal root ganglion, lingual muscle and jejunum of the rat were fixed over one day at room temperature in a fixative containing paraformaldehyde and glutaraldehyde. After fixation, specimens were treated with 5N KOH solution for 5-10 min at 60 degrees C, immersed in a collagenase solution for 3-5 h at 37 degrees C and processed for scanning electron microscopy (SEM). In adequately treated specimens, connective tissue matrices and basal laminae were completely removed without causing any severe tissue damage. The three-dimensional visualization of cellular elements of peripheral nerves was enabled with the following results: 1) Individual nerve fibers of the sciatic nerve were clearly exposed. Myelinated fibers were non-branching cords with local annular constrictions at the node of Ranvier, while unmyelinated ones branched and anastomosed with one another to form loose networks. The sites of accumulation of the Schwann cell cytoplasm swelled on the surface of the myelinated fibers. Mesaxons were visualized as longitudinal furrows. 2) Ganglion cells covered by satellite cells were observed in the dorsal root ganglion. The ganglion cells were covered by their own convoluted dendro-axonal processes, thus forming the initial glomeruli of Cajal. Satellite cells at the glomeruli extended many finger-like projections surrounding the dendro-axonal processes. 3) Motor endplates were observed in lingual muscles. Terminal Schwann cells (teloglia) at the endplate were clearly visualized: the round perikaryon extended cytoplasmic processes along the axonal branches within the endplate. The processes issued fine finger-like projections from their margins. 4) Vascular autonomic plexuses were clearly demonstrated in lingual muscles. Unmyelinated nerves branched and anastomosed to form elaborate nerve networks around the vessels. Neuronal processes and associated Schwann cells were identifiable at high magnification. 5) Submucous nerve plexuses in the jejunum consisted of numbers of ganglia and interconnecting strands of fibers which formed very complicated networks. These observations indicate that this modified KOH-digestion method is useful for the SEM study of the three-dimensional cellular organization of nervous elements in various tissues.     

Medial exposure for dissection of the cranial nerves in situ by medical students

In this article, we illustrate and briefly describe a medial approach, in the sagittally sectioned preserved human head, to display all of the cranial nerves, in situ and in continuity. The method has been successfully used by more than six cohorts of our second-year medical students, and can be completed within a 90-min dissecting session.     

An investigation into medical students' approaches to anatomy learning in a systems-based prosection course

Students' approaches to learning anatomy are driven by many factors and perceptions, e.g., the curriculum, assessment, previous educational experience, and the influence of staff and fellow students. However, there has been remarkably little research into characterizing how students approach their anatomy learning. What is known, based on a sample of 243 students, is that students studying medicine at the University of Southampton adopt primarily a "deep" approach to learning. Medical students at Southampton learn anatomy in a systems-based curriculum through prosections. Analysis of data from an Approaches to Study Inventory (ASSIST) revealed that students preferred using a deep approach over a strategic or surface approach (P < 0.001 and P < 0.001, respectively). They also adopted an increasingly strategic approach as they moved through the medical curriculum. There was a relationship between anatomy examination results and approach to learning. Students who adopted a strategic approach performed better (R = 0.266, P < 0.001). It is argued that curriculum design, including the form of assessment, is the key to promote effective anatomy education and the goal of deep and meaningful learning in preparation for professional practice.     

Near‐peer driven dissection selective: A primer to the medical school anatomy course

In the anatomy laboratory, skill remains a critical component to unlocking the true value of learning from cadaveric dissection. However, there is little if any room for provision of instruction in proper dissection technique. We describe how near‐peer instructors designed a supplemental learning activity to enhance the dissection experience for first‐year medical students. This study aimed to evaluate the efficacy of this curriculum in improving participants' understanding of dissection technique and its impact on perceived challenges associated with the anatomy course. Curriculum was designed under faculty guidance and included didactic sessions, low‐fidelity models, dissection, student presentations, and clinical correlations. Participants' (n = 13) knowledge of basic dissection techniques and concepts were assessed before the selective, and both participants' and nonparticipants' (n = 39) knowledge was assessed at the end of week one and week seven of the anatomy course. Scores were compared using repeated measures ANOVA followed by post hoc t‐tests. Thirteen deidentified reflective essays were reviewed by four independent reviewers for themes that aligned with learning objectives. Participants in the selective course scored higher on assessment of dissection techniques and concepts one week after the selective compared to both nonparticipants and their own baseline scores before the selective. Analysis of student reflections resulted in four themes: confidence with dissection skill, sharing resources and transfer of knowledge, learning environment, and psychological impact of perceived challenges of the anatomy course. Near‐peer driven supplemental exercises are effective in facilitating dissection skills. This dissection primer increases student confidence and alleviates apprehension associated with anatomy courses. Clin. Anat. 28:985–993, 2015. © 2015 Wiley Periodicals, Inc.     

First year medical students' approaches to study and their outcomes in a gross anatomy course

Three approaches to study have been described in phenomenographic educational research: deep, strategic, and surface. Deep approaches to learning have been correlated with meaningful learning and academic success, whereas surface approaches produce an externalization of learning and poor outcomes. Students adopting a strategic approach adopt either a deep or surface approach in response to perceived examination demands. Despite being well known in Europe and Australia, this research paradigm has been applied sporadically in the United States. In this study, the approaches to study of a group of first year American medical students were collected using the Approaches and Study Skills Inventory for Students instrument at the beginning and end of their first year to find how consistent these approaches remained over time. At both times, the majority of participants adopted deep approaches, followed by strategic and then surface approaches. The percentage of participants using a surface approach grew during the first year but never exceeded 10%. The mean anatomy grades of students adopting each approach were then compared to find how each approach correlated with success in the course. Mean grades of students using a strategic approach were significantly higher than average at both times. Students who maintained a strategic approach throughout the first year had significantly higher mean grades than average while students who changed to a surface approach had significantly worse mean anatomy grades. Problem-based students had significantly higher scores on several deep submeasures than lecture-based peers and female students demonstrated greater fear of failure than male peers at both times.     

Undulating course of nerve fibres and bands of Fontana in peripheral nerves of the rat

Summary The undulating course of nerve fibres and the optical effect of that course, i.e. the bands of Fontana, were studied in the peripheral nerves of the adult rat using light microscopy. The arrangement of collagen fibres in the endoneurium of these nerves was evaluated using transmission and scanning electron microscopy. No nerve fibres undulation was noted on the intracranial sections of the cranial nerves or on the spinal roots. In their endoneurium a few, irregularly arranged collagen fibrils were found. In contrast, the nerve fibres undulation and Fontana's bands were a constant feature in the peripheral course of the nerve trunks. They were discernible in vivo and on excised unfixed as well as fixed nerves. The nerve fibres follow a sine-curve course of variable frequence and amplitude. Exposed in vivo, the nerve fibres retained their wave-like course even after removal of the epineurium and perineurium. The endoneurium of these nerves contained numerous undulating longitudinally oriented bundles of collagen fibrils. These findings suggest that the undulating course of the nerve fibres in peripheral nerves is conditional upon the quantity and arrangement of their endoneurial collagen fibrils. When the nerve was stretched in the course of movement, the undulation became straightened out until it disappeared. Conversely, nerve shortening enhanced the undulation. Thus the wave-like alignment of the nerve fibres represents a physiological reserve length for nerve stretching.     

Anatomical variation in the anterolateral ligament of the knee and a new dissection technique for embalmed cadaveric specimens

Claes et al. recently documented and described the anterolateral ligament (ALL) of the knee, demonstrating its existence in 97% of their samples. Here, we further examined the anatomy of this ligament, documented its morphological variation, and assessed the feasibility of its dissection in preserved cadaveric specimens. To achieve this, we dissected 53 preserved cadaveric knees and documented their morphological variation in the anterolateral ligament. The originally described dissection technique for identifying and following the ALL requires flexion of the knee, a state which is often not possible in stiff, preserved cadavers. Here, we describe and confirm the feasibility of an alternate dissection technique in which the quadriceps femoris tendon is incised, for use on specimens in which flexion of the undissected knee is not possible. We also identify a novel technique for assessing whether the anterolateral ligament is absent from a specimen or has simply been obliterated or overlooked, using the lateral inferior genicular vasculature. These dissection techniques have great potential for the dissection of preserved cadavers used in gross anatomy laboratories, and we discuss the applications of such an approach in student-led dissections. Our dissections also uncovered noticeable variation in the anterolateral ligament course and position. Most notably, it often inserts significantly more laterally than the classical presentation (30.2%), or originates more proximally with superficial fibers extending superiorly and laterally over the distal femur (7.5%).     

Help of third-year medical students decreases first-year medical students' negative psychological reactions on the first day of gross anatomy dissection

The assistance of third-year medical students (MS3) may be an easy, inexpensive, educational method to decrease physical and emotional stress among first-year medical students (MS1) on the first day of gross anatomy dissection. In the academic years 2000-2001 and 2001-2002, a questionnaire on the emotional and physical reactions on the first day of dissection was distributed to 84 MS1 at Mayo Medical School (Rochester, MN); 74 (88%) responded. Student perceptions were assessed on a 5-point Likert scale. The 42 second-year medical students (MS2) whose first academic year was 1999-2000 were used as a control group, because they had not had assistance from MS3. MS2 completed the same questionnaire (59% response rate). Data were collected from MS1 on the day of their first gross anatomy dissection. The most frequent reactions were headache, disgust, grief or sadness, and feeling light-headed. Significant differences (alpha < 0.05) were found with use of the chi(2) test to compare the emotional and physical reactions of MS1 and MS2. MS1 had significantly fewer physical reactions (64% vs. 88%), reporting lower levels of anxiety (23% vs. 48%), headache (14% vs. 36%), disgust (9% vs. 20%), feeling light-headed (11% vs. 24%), and reaction to the smell of the cadaver and laboratory (8% vs. 52%). MS1 commented that having MS3 at the dissection table was extremely helpful. They relied less on their peers and felt they learned more efficiently about the dissection techniques and anatomical structures. Using MS3 as assistants is one method to reduce fear and anxiety on the first day of gross anatomy dissection.     

生物染料技术在检测前哨淋巴结中的应用

前哨淋巴结(sentinel lymph node，SLN)系指接受原发肿瘤部位淋巴引流的第一级淋巴结，最先反映肿瘤的转移情况，是进行病理学检查和指导是否需要进行广泛淋巴结清除术最有价值的淋巴结。自从Cabanas于1977年首次将其引入肿瘤治疗以来，前哨淋巴结活检等技术已在许多肿瘤的临床实践中得到应用和发展，目前文献所报道的前哨淋巴结检出率差别较大，前哨淋巴结检测成功率除了与病人因素外，     

Application of modified ultrafast Papanicolaou stain in cytology of various organs

This prospective study was conducted to assess the use of modified ultrafast Papanicolaou (MUFP) stain for fine-needle aspiration cytology (FNAC) of various organs. In India, many reagents are not easily available. In this modification, Gill's haematoxylin, EA-36, and isopropanol substitute Richard-Allan haematoxylin, cytostain, and ethanol, respectively. Group I included 40 FNAC smears of various organs. In each case, three smears were prepared and stained by MUFP, Papanicolaou, and May-Grunwald Giemsa (MGG) stains. In group II, 10 intraoperative cytology smears of different organs were stained with MUFP and rapid haematoxylin-eosin (H&E). For assessment of MUFP stain, scores were given on four parameters: background of smears, overall staining pattern, cell morphology, and nuclear staining. Quality index was calculated from ratio of score achieved to maximum possible score. Diagnosis made by MUFP stain was compared with standard stains. It was observed that MUFP-stained smears had clear RBC free background, crisp nuclear chromatin, well-stained nucleoli, and transparent cytoplasm. The diagnosis made was correct except in three cases of metastatic squamous-cell carcinoma. Hence, it was concluded that MUFP stain is useful for rapid diagnosis by FNAC, but is not useful for squamous-cell lesions.     

Experimental validation of direct long electrostimulation after neurotransplantation of the peripheral nerves

Effects of direct long-term electric stimulation on the growth of the sciatic nerve regenerating axons through autoneurotransplants were studied in rabbits and an optimal electrostimulation method was developed. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 4, pp. 470–472, April, 2007