Utility of Circulating Cell-Free DNA in Assessing Microsatellite Instability and Loss of Heterozygosity in Breast Cancer Using Human Identification Approach.

The diagnostic and prognostic utility of circulating cell-free DNA (cfDNA) in breast cancer (BC) patients was recently reported. Here, we investigated the use of cfDNA to examine microsatellite instability (MSI) and loss of heterozygosity (LOH) for early BC diagnosis. cfDNA and genomic DNA from 41 female BC patients and 40 healthy controls were quantified using NanoDrop spectrophotometry and real-time PCR. The stability of genomic and cfDNA was assessed using a high-resolution AmpFlSTR MiniFiler human identification kit. Significant increases in cfDNA plasma concentrations were observed in BC patients compared to controls. The genotype distribution of the eight autosomal short tandem repeat (STR) loci D7S820, D13S317, D21S11, D2S1338, D18S51, D16S539, FGA, and CSF1PO were in Hardy-Weinberg equilibrium. Significant differences in the allele frequencies of D7S820 allele-8, D21S11 allele-29, allele-30.2, allele-32.2, and CSF1PO allele-11 were seen between BC patients and controls. LOH and MSI were detected in 36.6% of the cfDNA of patients compared to genomic DNA. This study highlights the utility of plasma-derived cfDNA for earlier, less invasive, and cost-effective cancer diagnosis and molecular stratification. It also highlights the potential value of cfDNA in molecular profiling and biomarkers discovery in precision and forensic medicine.

The anatomy of the accessory nerve and cervical lymph node biopsy.

Injury to the accessory nerve is the most frequent complication of surgical procedures in the posterior triangle of the neck. The symptoms produced by paralysis of the trapezius are disabling. The components of this disability are pain, limitation of abduction, and drooping of the affected shoulder. A detailed knowledge of the course of the nerve and its anatomic relations are essential in avoiding injury. Useful anatomic landmarks are the proximal internal jugular vein in the anterior triangle and Erb's point in the posterior triangle. Prevention of accessory nerve injury is the best management. The indications for lymph node biopsies in the neck should be sound. The use of a general anesthetic without paralysis is recommended if an excisional biopsy is necessary. Adequate exposure is essential. Whether the nerve needs to be identified in all cases has to be individualized and requires careful judgment. A divided or injured nerve is best managed with primary repair within 3 months of injury.

Assessment of tissue viability using near-infrared spectroscopy.

Prolonged and severe tissue hypoxia results in tissue necrosis in pedicled flaps. We demonstrate the potential of near-infrared spectroscopy for monitoring of skin flaps. This approach clearly identifies tissue regions with low oxygen supply, and also the severity of this challenge, in a rapid and non-invasive manner with a high degree of reproducibility. Tissue haemoglobin oxygen saturation and water content of pre-selected dorsal sites were monitored for 72 h prior to, and 72 h following elevation of a reversed McFarlane rat dorsal skin flap (n = 9). Oxygen delivery to flap tissue dropped immediately upon flap elevation. This was most pronounced in the distal half of the flap and least pronounced in the region nearest its base. Haemoglobin oxygen saturation of tissue proximal to the vascular base of the flap recovered, exceeding pre-elevation saturation values, within 6 h of raising the flap. Typically, this higher haemoglobin oxygen saturation persisted for the full 72 h post-elevation observation period. At a distance greater than 2 cm from the vascular pedicle, the tissue remained hypoxic over the post-elevation monitoring period. Tissues remaining below a certain haemoglobin oxygen saturation threshold (oxygen saturation index < 1) for prolonged periods (> 6 h) became increasingly dehydrated, eventually becoming visibly necrotic. Tissues above this threshold (oxygen saturation index > 1), despite being significantly hypoxic, relative to the pre-elevation saturation values, remained viable over the 72 h post-elevation monitoring period.

Tissue viability by multispectral near infrared imaging: a fuzzy C-means clustering analysis.

Clinically, skin color, temperature, and capillary perfusion are used to assess tissue viability following microvascular tissue transfer. However, clinical signs that arise as a consequence of poor perfusion become evident only after several hours of compromised perfusion. This study demonstrates the potential usefulness of optical/infrared multispectral imaging in the prognosis of tissue viability immediately post-surgery. Multispectral images of a skin flap model acquired within 1 h of surgical elevation are analyzed in comparison to the final 72-h clinical outcome with a high degree of correlation. Regional changes in tissue perfusion and oxygenation present immediately following surgery are differentiated using fuzzy clustering and image processing algorithms. These methodologies reduce the intersubject variability inherent in infrared imaging methods such that the changes in perfusion are reproducible and clearly distinguishable across all subjects. Clinically, an early prognostic indicator of viability such as this would allow for a more timely intervention following surgery in the event of compromised microvasculature.