Vimentin Diversity in Health and Disease

Vimentin is a protein that has been linked to a large variety of pathophysiological conditions, including cataracts, Crohn's disease, rheumatoid arthritis, HIV and cancer. Vimentin has also been shown to regulate a wide spectrum of basic cellular functions. In cells, vimentin assembles into a network of filaments that spans the cytoplasm. It can also be found in smaller, non-filamentous forms that can localise both within cells and within the extracellular microenvironment. The vimentin structure can be altered by subunit exchange, cleavage into different sizes, re-annealing, post-translational modifications and interacting proteins. Together with the observation that different domains of vimentin might have evolved under different selection pressures that defined distinct biological functions for different parts of the protein, the many diverse variants of vimentin might be the cause of its functional diversity. A number of review articles have focussed on the biology and medical aspects of intermediate filament proteins without particular commitment to vimentin, and other reviews have focussed on intermediate filaments in an in vitro context. In contrast, the present review focusses almost exclusively on vimentin, and covers both ex vivo and in vivo data from tissue culture and from living organisms, including a summary of the many phenotypes of vimentin knockout animals. Our aim is to provide a comprehensive overview of the current understanding of the many diverse aspects of vimentin, from biochemical, mechanical, cellular, systems biology and medical perspectives.

Use of transoesophageal echocardiography during the peri-operative period for trauma patients

The medical facility at Camp Bastion continues to evolve as a consequence of the increased throughput of battlefield trauma patients. There is a requirement for rapid and accurate diagnosis of haemodynamic instability and continued haemodynamic monitoring throughout the peri-operative period. Transoesophageal echocardiography (TOE) has been used for this purpose in the arena of cardiac anaesthesia since the mid 1980s. It is being introduced to other peri-operative settings where severe haemodynamic instability is expected. The old proverb: 'There are none so blind as those who cannot see' (Jeremiah 5:21) is applicable to this topic, in that TOE is proven to be a rapid, portable, safe and effective tool in the assessment of the haemodynamically unstable patient. This paper explores the application of TOE for the assessment of the major causes of haemodynamic instability in the trauma population.

Comparison of plain and hyperbaric solutions of ropivacaine for spinal anaesthesia †

BACKGROUND

Preliminary work has shown that ropivacaine provides spinal anaesthesia of shorter duration than bupivacaine, and may be of particular use in the day-case setting. However, there are few data comparing the actions of plain and hyperbaric solutions of this drug.

METHODS

Forty ASA grade I-II patients undergoing elective perineal surgery under spinal anaesthesia were randomized to receive 3 ml ropivacaine 5 mg ml(-1), either in plain solution or with glucose 50 mg ml(-1). The extent and duration of sensory and motor block, pulse rate, blood pressure, and time to mobilization were recorded.

RESULTS

Two patients (one per group) were withdrawn because of total block failure. There were significant differences in median time to onset of sensory block at T10 (plain 10 min; hyperbaric 5 min; P<0.01), median maximum extent (plain T8; hyperbaric T4; P<0.05), and median duration of sensory block at T10 (plain 25 min; hyperbaric 115 min; P<0.001). However, median times to complete regression of both sensory (270 vs 240 min; P<0.05) and motor (180 vs 120 min; P<0.001) block were longer in the plain group. Patients therefore mobilized sooner in the hyperbaric group (218 [n=16] vs 286 min [n=17]; P<0.01). All the hyperbaric blocks were adequate for surgery, but three patients receiving plain ropivacaine required general anaesthesia.

CONCLUSION

Addition of glucose 50 mg ml(-1) to ropivacaine 5 mg ml(-1) increases the speed of onset, block reliability, duration of useful block for perineal surgery, and speed of recovery. Plain solutions are less reliable for surgery above a dermatomal level of L1.

Assessment of pathologic prognostic factors in breast core needle biopsies

BACKGROUND

Core needle biopsies (CNB) are being used increasingly as the initial diagnostic procedure in women with breast cancer. Many clinicians are interested in obtaining as much prognostic information as possible from these limited specimens. However, the accuracy of assessing pathologic prognostic factors in core biopsy material has not been studied in detail.

DESIGN

We studied CNB and subsequent excision specimens from 79 women with invasive breast cancer. Slides from CNB and excision specimens were reviewed in a blinded fashion and each was assessed for histologic type, tumor size, histologic grade, lymphatic vessel invasion (LVI), and the presence of an extensive intraductal component (EIC).

RESULTS

Among the 79 cancers, there were 58 invasive ductal carcinomas, six invasive lobular carcinomas, 13 invasive carcinomas with ductal and lobular features and two tubular carcinomas, based on examination of the excision specimens. Histologic type on CNB correlated with that on excision in 64 cases (81%). Although there was a significant correlation between tumor size on CNB and excision specimens (r2 = 0.30, P = 0.01), the pathologic T stage was underestimated on CNB in 79% of cases. Furthermore, T substage was underestimated on CNB in 71% of T1 lesions. There was concordance in histologic grade between CNB and excisions in 75% of cases. Among the 20 discordant cases, the grade was higher in the excision than in the CNB in 13 cases and lower in seven. However, all discrepancies were within one grade. None of the 17 cancers with LVI in the excision specimen showed LVI on the CNB. Among 14 cases with an EIC on the excision specimen, only four (29%) were scored as having an EIC on CNB.

CONCLUSION

Histologic type can be accurately determined on CNB in most cases. While there was concordance in histologic grade between CNB and excision in the majority of cases, grade was discordant in a substantial minority (25%). The ability to accurately determine tumor size (pathologic T-stage), LVI, and EIC on CNB is severely limited.

Effects of nutrient supplementation in beef cows of poor body condition fed snakeweed (Gutierrezia spp)

Two replicate trials determined the effects of dietary supplementation on snakeweed toxicity in beef cows of poor condition. Cows were stratified by weight and randomly assigned to 3 dietary treatments. Dietary treatments were control (n = 3/trial; medium quality hay, 9.49% crude protein), corn supplementation (n = 3/trial; control diet + 628 g cracked corn), and protein supplementation (n = 3/trial; control diet + 800 g 42% protein supplement). Corn and protein dietary treatments were fed to be isocaloric. Each trial consisted of 2 phases (68 days/phase). Phase 1 consisted of dietary treatments without snakeweed. In phase 2 dietary treatments contained snakeweed as 10% of the dry matter. Phase 1 and 2 dietary treatments were isocaloric/isonitrogenous. Dry matter intake of the control diet was limited to 1.3% of body weight/d. Body condition score and back fat were measured on days 0, 21 and 68 of each phase. Serum samples were collected at the onset of each trial and on days 28, 42 and 56 of each phase. Serum bromosulphthalein (BSP) elimination half life (t1/2) was estimated during week 6 of each phase. Serum BSP elimination t1/2 was higher for the control diet versus corn and protein treatments. Increased blood urea nitrogen (BUN) was found by day 28 of phase 2. Serum total bilirubin increased by day 28 in phase 2 compared to baseline for the control and corn dietary treatments. Additionally, serum indirect bilirubin was higher by day 28 in phase 2. Likewise, serum direct bilirubin increased during phase 2 on day 28 in the corn diet, but decreased by day 28 for the protein diet. Alkaline phosphatase levels were higher (P < 0.05) in the controls by day 28, but lower in the protein treatment by day 28 in phase 2. Changes were noted during phase 2 for some of the serum clinical profiles; however, these changes appear due to dietary restriction. In contrast, changes during phase 2 point to possible hepatotoxic and renal toxic effects of snakeweed. Phase 2 data suggest a benefit of protein supplementation for improving animal tolerance to snakeweed.

Effects of tumor necrosis factor alpha and vascular permeability factor on neovascularization of the rabbit ear flap

OBJECTIVE

The survival of compromised skin flaps depends on neovascularization for their nutrition and metabolic waste removal. Our study investigated the effectiveness of angiogenic factors in accelerating peripheral neovascularization and in increasing skin flap viability.

DESIGN

We elevated pedicled dorsal skin flaps on the ears of 23 New Zealand white rabbits, and the vascular pedicle was ligated to achieve partial flap necrosis. Fifteen flaps were treated with 0.1 micrograms/mL vascular permeability factor, and eight flaps were treated with 1.0 micrograms/mL tumor necrosis factor alpha. The ear flaps that were not treated with growth factor functioned in each rabbit as a normal saline control.

MAIN OUTCOME MEASURES

The viability of skin flaps was observed visually and was measured by Cartesian planimetry using templates. Neovascularization was documented by microangiography and by histologic analysis of the flaps.

RESULTS

Although the angiogenic factors accelerated neovascularization, increased flap survival was demonstrated only in those animals treated with vascular permeability factor that was supplied by an absorbable gelatin sponge.

CONCLUSION

This experimental model, despite different levels of controls, contains multiple variables, including the use of an absorbable gelatin sponge, seroma formation, bioactivity of the angiogenic factors, optimal dosages and dosimetry, the need for a "blinded" format, and the validity of the histologic analysis. Additional investigation must be done and the experimental model itself must be improved before these apparently positive results may be accepted as clinically useful.