Evaluation of a replanted finger and measuring its perfusion changes to predict its viability by laser speckle contrast imaging

<p class="abstract"><strong>Background:</strong> This research aims to monitor the microcirculation of the replanted finger, which was entirely severed by using laser speckle contrast imaging (LSCI) for early detection and revision of vascular compromise for successful finger replantation.</p><p class="abstract"><strong>Methods:</strong> These six months of research was taken for a survey of 40 cases of replanted fingers of patients of distinct ages and sex. Scrutinizing was done postoperatively by LSCI, every hourly for seven days, to assess changes in blood perfusion both in replanted fingers and healthy ones and analyzed graphically. </p><p class="abstract"><strong>Results:</strong> Initially, from postoperative d=0 to d=2, the perfusion value was at baseline, which ranged 40±15 perfusion unit (PU), showing a wave-like curve, then gradually increased up to 350±50 PU or above in case of those which survived successfully, showing continuous peak slope. However, a gradual drop in perfusion, &lt;35 PU from d=2 or d=3, was seen in those despite undergoing heparinized finger pin-prick bleeding therapy and failed to thrive, showing a downslope curve. Whereas some were under meticulous observation, which flourished lately. Concurrently, a comparison was made with the healthy fingers’ of the same patient, ranging from 200±50 to as high as 400±50 or above. Clinical correlation, as well as perfusion readings of LCSI, were done simultaneously.</p><p class="abstract"><strong>Conclusions:</strong> LSCI provides sensitive and reproducible finger microcirculation measurements and is reliable in predicting reductions in blood perfusion induced by venous or arterial occlusion. It is, therefore, an informative device to detect microvascular compromise during and after replantation surgery.</p>

Changes in gingival blood flow during orthodontic treatment

The aim of the study was to investigate the changes in gingival blood flow due to orthodontic forces. Eleven volunteers, with the maxillary canine in an ectopic position were tested. A Laser Doppler Flowmeter (LDF) with a gingival probe was used, registering both the blood flow and temperature of the gingivae. After baseline measurement, a fixed orthodontic appliance was bonded. Measurements were repeated monthly, after activation of the appliance. The study lasted 6 months. The baseline value was 338.7 ± 201.56 P.U. [Perfusion Unit (mean ± S.D.)] which decreased to 218.9 ± 74.83 P.U. (p < 0.05) after two months and the final value of 363.9 ± 194.86 P.U was not significantly different from that initially (p > 0.5). The results showed that application of a force of 75 g resulted in a decrease in gingival blood flow up to 50%, but this returned to previous values after a few months. The study supports this measurement technique as a useful tool for monitoring gingival blood flow in long-term studies as well.

Influence of Anaesthesia on the Regional Distribution of Perfusion and Ventilation in the Lung

1. Distribution of lung volume, pulmonary ventilation and perfusion were studied in supine patients before and during anaesthesia with paralysis and artificial ventilation. Inspired gas and pulmonary blood flow were measured with 133xenon and the chest was scanned with vertically moving counters at a lung volume of 1 litre above functional residual capacity. 2. Ventilation/unit lung volume was slightly greater and perfusion/unit lung volume substantially greater during anaesthesia in the dependent parts of the lungs. The spread of ventilation/perfusion ratios in supine conscious patients was small in comparison with that reported in upright conscious patients. During anaesthesia and artificial ventilation, the inequality of ventilation to perfusion was marginally increased in three of the four patients. 3. Ventilation/perfusion inequality alone was insufficient to explain the alveolar—arterial Po2 difference usually observed during anaesthesia.

The Oxidation of Cysteine to Sulphate in Soil

The oxidation of cysteine to sulphate by a mixed population of soil microorganisms was studied in a perfusion unit. Intermediates in this reaction were identified by paper chromatography and by an enrichment-reperfusion technique.