Segond fracture in an adult is not pathognomonic for ACL injury

The Segond fracture is an avulsion fracture of the lateral tibial plateau and is considered pathognomonic for anterior cruciate ligament (ACL) injury. A case of a Segond fracture occurring with a clinically, radiologically and arthroscopically intact ACL is presented. This was associated with a serious injury to the posterolateral corner requiring surgical reconstruction. Relevant literature is discussed, and the suggestion is made that, whilst an ACL rupture may be the most commonly noted soft tissue component associated with a Segond fracture, the clinician should have a high level of suspicion for other serious soft tissue injuries. Level of evidence V.

Transitional B lymphocytes are associated with protection from kidney allograft rejection: a prospective study

Recent cross-sectional studies suggest an important role for transitional B lymphocytes (CD19 + CD24hiCD38hi) in promoting transplant tolerance, and protecting from late antibody-mediated rejection (ABMR). However, prospective studies are lacking. This study enrolled 73 de novo transplant recipients, and collected serial clinical, immunological and biochemical information over 48 ± 6 months. Cell phenotyping was conducted immediately prior to transplantation, and then on five occasions during the first year posttransplantation. When modeled as a time-dependent covariate, transitional B cell frequencies (but not total B cells or "regulatory" T cells) were associated with protection from acute rejection (any Banff grade; HR: 0.60; 95% CI: 0.37-0.95; p = 0.03). No association between transitional B cell proportions and either de novo donor-specific or nondonor-specific antibody (dnDSA; dnNDSA) formation was evident, although preserved transitional B cell proportions were associated with reduced rejection rates in those patients developing dnDSA. Three episodes of ABMR occurred, all in the context of nonadherence, and all associated with in vitro anti-HLA T cell responses in an ELISPOT assay (p = 0.008 versus antibody-positive patients not experiencing ABMR). This prospective study supports the potential relevance of transitional ("regulatory") B cells as a biomarker and therapeutic intervention in transplantation, and highlights relationships between humoral immunity, cellular immunity and nonadherence.

Eukaryote to gut bacteria transfer of a glycoside hydrolase gene essential for starch breakdown in plants

Lateral gene transfer (LGT) between bacteria constitutes a strong force in prokaryote evolution, transforming the hierarchical tree of life into a network of relationships between species. In contrast, only a few cases of LGT from eukaryotes to prokaryotes have been reported so far. The distal animal intestine is predominantly a bacterial ecosystem, supplying the host with energy from dietary polysaccharides through carbohydrate-active enzymes absent from its genome. It has been suggested that LGT is particularly important for the human microbiota evolution. Here we show evidence for the first eukaryotic gene identified in multiple gut bacterial genomes. We found in the genome sequence of several gut bacteria, a typically eukaryotic glycoside-hydrolase necessary for starch breakdown in plants. The distribution of this gene is patchy in gut bacteria with presence otherwise detected only in a few environmental bacteria.

We speculate that the transfer of this gene to gut bacteria occurred by a sequence of two key LGT events; first, an original eukaryotic gene was transferred probably from Archaeplastida to environmental bacteria specialized in plant polysaccharides degradation and second, the gene was transferred from the environmental bacteria to gut microbes.

Copeptin and arginine vasopressin at high altitude: relationship to plasma osmolality and perceived exertion

PURPOSE

A diuresis is a key part of acclimatisation to high altitude (HA). Arginine vasopressin (AVP) is a hormone involved in salt and water balance and may potentially have a role in the development of altitude illness. ProAVP (copeptin) is more stable than AVP and is assayed by a straightforward, automated method. We investigated the relationship of AVP to copeptin and the copeptin response to exercise and altitude illness in a large cohort during a field study at HA.

METHODS

48 subjects took part in a 10-day trek at HA. Venous blood samples were taken at 3,833, 4,450 and 5,129 m post-trek (exercise) and the following day at rest. Daily recordings of symptoms of altitude illness, oxygen saturations and perceived exertion were carried out.

RESULTS

AVP and copeptin levels increased with exercise and correlated closely (ρ 0.621 p < 0.001), this was strongest in the stressed state when AVP secretion was highest, at 5,129 m post-exercise (ρ 0.834 p < 0.001). On two-way ANOVA, both altitude (F = 3.5; p = 0.015) and exercise (F = 10.2; p = 0.002) influenced copeptin levels (interaction F = 2.2; p = 0.08). AVP levels were influenced by exercise (F = 14.4; p = 0.0002) but not altitude (F = 2.0; p = 0.12) with no overall group interactions (F = 1.92.6; p = 0.06). There was no association between copeptin or arginine vasopressin and altitude illness. Copeptin correlated with the Borg RPE score and was significantly higher in the group with a Borg score ≥15 (7.9 vs. 3.7 p < 0.001).

CONCLUSION

We have shown that arginine vasopressin and copeptin levels correlate and are suppressed below 5,129 m. Furthermore, we have demonstrated that exertion, rather than altitude illness or increasing osmolality, is the stimulus for increases in copeptin.

Acute kidney injury following unselected emergency admission: role of the inflammatory response, medication and co-morbidity

BACKGROUND/AIMS

Acute kidney injury (AKI) following admission to hospital is associated with increased mortality, morbidity and length of stay. Factors that predispose patients to AKI frequently co-exist. The precise description of their representation in unselected admissions could help define mechanistic inter-relationships and optimise risk stratification strategies. Our aim was therefore to define precisely, using electronically available data, the variables that are associated with AKI.

METHODS

A cohort study of 112,987 emergency admissions to an urban academic medical centre between 2006 and 2010 was performed. Post-admission AKI was defined using KDIGO aligned, proportionate changes in serum creatinine, denominated by the first measured. AKI correlated with co-morbidities, medications received and the C-reactive protein concentration (CRP).

RESULTS

The relationship between post-admission AKI and putative risk factors was defined in univariate and multivariate analyses. Inclusion of CRP in multivariate analyses significantly reduced the strength of association between some co-variables such as radiological contrast and gentamicin administration but not others.

CONCLUSION

The effect of CRP in these analyses supports the role of systemic inflammation in susceptibility to post-admission AKI. It accounts for the greater part of univariate associations between AKI and some nephrotoxic agents, placing the risk attributable to their use in context. Quantification of the systemic inflammatory response may have utility in AKI risk stratification, integrating various determinants of susceptibility.

Genome of the red alga Porphyridium purpureum

The limited knowledge we have about red algal genomes comes from the highly specialized extremophiles, Cyanidiophyceae. Here, we describe the first genome sequence from a mesophilic, unicellular red alga, Porphyridium purpureum. The 8,355 predicted genes in P. purpureum, hundreds of which are likely to be implicated in a history of horizontal gene transfer, reside in a genome of 19.7 Mbp with 235 spliceosomal introns. Analysis of light-harvesting complex proteins reveals a nuclear-encoded phycobiliprotein in the alga. We uncover a complex set of carbohydrate-active enzymes, identify the genes required for the methylerythritol phosphate pathway of isoprenoid biosynthesis, and find evidence of sexual reproduction. Analysis of the compact, function-rich genome of P. purpureum suggests that ancestral lineages of red algae acted as mediators of horizontal gene transfer between prokaryotes and photosynthetic eukaryotes, thereby significantly enriching genomes across the tree of photosynthetic life.

Prophylactic decompression of extensor pollicis longus to prevent rupture

We present a case of a patient with spontaneous rupture of right extensor pollicis longus (EPL) tendon, who had also developed left wrist pain and weakness in his left EPL that MRI studies confirmed to be caused by tendinosis. Subsequently, decompression of left EPL and reconstruction of right EPL with palmaris longus tendon graft was undertaken. In this case, decompression of the left EPL tendon led to resolution of the patient's symptoms as well as preventing tendon rupture. We advocate the use of ultrasound imaging to evaluate EPL in these cases and prophylactic decompression of EPL tendon to avoid rupture in those patients found to have tendinosis.

Temporal effects of maternal and pregnancy characteristics on serum pregnancy-associated plasma protein-A and free β-human chorionic gonadotropin at 7-14 weeks' gestation

OBJECTIVE

The aim of this study was to investigate gestational age-dependent effects of racial origin, smoking status and mode of conception on maternal serum levels of free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 7-14 weeks' gestation.

METHODS

This was an analysis of data from prospective first-trimester combined screening for aneuploidies in singleton pregnancies, with β-hCG and PAPP-A measured at 7 + 1 to 14 + 3 weeks' gestation. We included 27,908 pregnancies from three centers in the U.K. and 125,461 pregnancies from 22 centers in Denmark, all with known normal fetal karyotype or resulting in the birth of a phenotypically normal neonate. Multiple regression modelling of log10 -transformed marker concentrations was used to produce log10 multiple of the median (MoM) values for free β-hCG and PAPP-A and to examine pregnancy characteristics that have significant effects on marker concentrations.

RESULTS

Serum free β-hCG and PAPP-A concentrations were significantly affected by gestational age, maternal weight, racial origin, parity, smoking and mode of conception. There were significant gestational age-dependent effects attributed to Afro-Caribbean race, smoking and conception through in-vitro fertilization (IVF) on PAPP-A and free β-hCG levels. In women of Afro-Caribbean race there was a weekly increase in PAPP-A of 5.3% and in free β-hCG of 1.8%. In smokers there was a weekly decrease in PAPP-A of 2.4% and in free β-hCG of 1.6%. In cases of IVF conceptions there was a weekly increase in PAPP-A of 4.5% and in free β-hCG of 4.6%.

CONCLUSIONS

Serum free β-hCG and PAPP-A concentrations at 7-14 weeks' gestation are affected by several pregnancy characteristics. The effects of Afro-Caribbean race, smoking and IVF conception change with gestational age.

Prospective study evaluating performance of first-trimester combined screening for trisomy 21 using repeat sampling of maternal serum markers PAPP-A and free β-hCG

OBJECTIVE

To prospectively evaluate the performance of first-trimester combined screening for trisomy 21 using the biochemical markers pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin (free β-hCG) obtained before and at the time of the nuchal translucency (NT) scan.

METHODS

Three fetal medicine departments in Denmark participated in the study. Screening for trisomy 21 was set up as a two-step approach with blood sampling performed before the NT scan (early sample) and again at the time of the NT scan (late sample). PAPP-A and free β-hCG were measured on both the early and late samples. Age-standardized detection and false-positive rates for different screening protocols were calculated.

RESULTS

We collected two blood samples in 27 pregnancies affected by trisomy 21 and in 3891 control pregnancies. The early samples were taken between gestational ages 8 + 0 and 13 + 6 weeks, and the late samples between 11 + 3 and 14 + 6 weeks. The median interval between the samples was 17 (range, 1-40) days. We found a significantly better estimated screening performance when using early sampling vs late sampling (P < 0.05). With a risk cut-off of 1 in 100, at the time of the risk assessment the estimated detection and false-positive rates when using the early sample were 91% (95% CI, 81-98%) and 1.6% (95% CI, 1.3-2.0%), respectively. For fixed false-positive rates the highest detection rates were achieved using both blood samples. When comparing early sampling vs double sampling there was no significant difference in screening performance.

CONCLUSION

In combined first-trimester screening for trisomy 21, use of early sampling with measurement of PAPP-A and free β-hCG before the time of the NT scan can optimize screening performance. Using maternal serum markers obtained both before and at the time of the NT scan has the potential to further improve performance, but larger studies are needed to confirm this potential.

Minimising the risk of accidental dural puncture with epidural analgesia for labour: a retrospective review of risk factors

BACKGROUND

Accidental dural puncture has a quoted incidence of between 0.19% and 3.6% of obstetric epidurals and is associated with significant morbidity. We set out to determine possible factors associated with an increased risk of accidental dural puncture.

METHODS

We performed a retrospective review of 18385 epidurals, performed over a 15-year period. Factors analysed were: time of day of insertion, loss-of-resistance technique, maternal position, cervical dilatation, grade of anaesthetist and depth to the epidural space.

RESULTS

Using univariate analyses we found no association between the risk of accidental dural puncture and the following variables: time of day of insertion (P=0.71), loss-of-resistance technique (P=0.22), maternal position for insertion (P=0.83), degree of cervical dilatation (P=0.41) and grade of anaesthetist performing the epidural (P=0.34). Conversely, we found that the risk of accidental dural puncture increased with increasing depth to the epidural space. This was confirmed using a logistic regression analysis, from which it was estimated that, for every 1-cm increase in depth, the risk of accidental dural puncture increased by approximately 19% (P=0.019; 95% CI for OR: 1.029-1.38).

CONCLUSION

We conclude that the risk of accidental dural puncture increases with increasing depth to the epidural space. We suggest further study is required to correlate this risk with increasing body mass index.

FDG-PET based dose escalated adjuvant tomotherapy (image-guided intensity-modulated radiotherapy) utilizing 4D-CT planning for high-risk adrenocortical carcinoma (ACC): A case study

e13522

Background: ACC is a rare endocrine malignancy with an annual incidence of 0.5-2/million/year. Surgery is the mainstay of treatment but relapse rate is high and the prognosis is dismal (20-50% 5 year survival). Adjuvant Radiotherapy improves local control in cases with high risk of local failure and dose escalation may achieve better results. Dose Escalation with 3-Dimensional computed tomography (CT) based radiotherapy is difficult for ACC due to unacceptable toxicity to several adjacent organs at risk (OARs) e.g., the kidneys, stomach bowel, liver, spinal cord. FDG-PET helps delineation of areas of higher metabolic activity and density of clonogenic cells within the target (Biological Target Volume or BTV) where focal dose escalation could be directed safely for improving local control as in other solid tumours. Tomotherapy (IMRT with daily image guidance) delivers precision radiotherapy with integrated boost to the BTV, lower dose to OARs, improved coverage of the targets, and better dose delivery across the targets which are essential for tumour control. 4-Dimensional CT for planning allows adequate Clinical Target Volume(CTV) coverage despite respiratory movements. Methods: A 63 year old lady had left adrenalectomy for an adrenocortical carcinoma measuring 29 x 18 x 25mm (TNM pT1NXMX) thought to be microscopically incompletely excised (R1) with a proliferation index ( Ki-67) of 40% for which adjuvant radiotherapy was advised. PET-CT, 4D-CT and Tomotherapy were used for planning. A total dose of 50.4Gy to PTV with a simultaneous integrated boost to BTV taking it up to 59.40Gy (1.98Gy/ fraction) in 30 daily fractions was prescribed. Results: Target dose and coverage were very satisfactory. The doses to OARs were well within tolerance despite dose escalation; she completed treatment with only grade- fatigue. She had metastatic disease at 11 months follow-up without local relapse. Conclusions: To our knowledge this is the first report of using FDG –PET based dose escalation, 4D CT and Tomotherapy in high risk ACC to improve local control and needs further study.

Objective assessment of thirst recovery in patients with adipsic diabetes insipidus

Adipsic diabetes insipidus (ADI) is characterised by impaired thirst and defective AVP secretion. We have assessed the thirst response to graded osmotic stimulation using a visual analog scale (VAS) in patients with a history of ADI following surgery for a craniopharyngioma. The patients were thought to be regaining their thirst response but we wanted to confirm that this was the case objectively before relaxing their strict fluid balance regimen. Three patients with adipisa in the presence of hypernatremia following surgery for a craniopharyngioma are described. Their median age at surgery was 13 years (range 11-15 years). All patients had previously demonstrated no desire to drink despite a serum osmolality in excess of 300 mOsmol/kg. Fluid balance was maintained postoperatively with a regimen involving a fixed daily fluid intake and DDAVP dose together with daily weights and regular assessment of capillary sodium concentrations. Patients were thought to be regaining thirst sensation and so were assessed by hypertonic saline infusion (HSI) with thirst measured using a VAS. Patients underwent a HSI test 4, 6 and 9 months post surgery. All had abnormally low AVP production at raised plasma osmolalities but the visual analogue scale confirmed partial or complete thirst recovery. The intensive regimen used to maintain stable serum sodium concentrations was relaxed without the patients subsequently developing a significant hyperosmolar state. We have shown objective recovery of thirst perception in patients with adipsia within 9 months of surgery, despite persistence of cranial diabetes insipidus. These observations indicate that both osmoreceptors regulating thirst and their efferent pathways demonstrate more plasticity than those regulating AVP production. The HSI and thirst VAS are an objective way of assessing patients known to have ADI who are thought to be recovering thirst perception.