Hair tourniquet syndrome: A retrospective study.

OBJECTIVE: Hair thread tourniquet syndrome (HTS) is a pediatric condition in which human hair or synthetic fiber encircles and strangulates a body appendage causing tissue necrosis. Few epidemiologic studies have been done. Our objective was to better define the demographics, clinical features, and predisposing factors for this condition. MATERIALS AND METHODS: Medical records of all infants up to 1 year old seen in the orthopedic emergency department of Galilee Medical Center were searched for the diagnosis of HTS or its ICD equivalent. RESULTS: Forty-one cases of hair tourniquet syndrome (HTS) were reviewed. Most cases (68%) occurred during the winter months (December to February). There were no reports between June to August (summer). The median age was 4 months and the male-to-female ratio was approximately 2:5. Toes were significantly more involved than fingers (97.5%) and the 3rd toe was the most affected (58%). Nine patients (21.9%) had more than one toe affected and only one case reported finger involvement. CONCLUSIONS: HTS in our population is a phenomenon that seems to occur mostly in winter. Infants between 3 and 5 months are at greater risk. Toes are more affected than fingers. The most involved toes are the 3rd and 4th.

Homogentisic Acid and Gentisic Acid Biosynthesized Pyomelanin Mimics: Structural Characterization and Antioxidant Activity.

Pyomelanin mimics from homogentisic acid (HGA) and gentisic acid (GA) were biosynthesized by the oxidative enzyme T. versicolor laccase at physiological pH to obtain water soluble melanins. The pigments show brown-black color, broad band visible light absorption, a persistent paramagnetism and high antioxidant activity. The EPR approach shows that at least two different radical species are present in both cases, contributing to the paramagnetism of the samples. This achievement can also shed light on the composition of the ochronotic pigment in the Alkaptonuria disease. On the other hand, these soluble pyomelanin mimics, sharing physico-chemical properties with eumelanin, can represent a suitable alternative to replace the insoluble melanin pigment in biotechnological applications.

[HAIR TOURNIQUET SYNDROME - A DISCREPANCY BETWEEN INCIDENCE AND DOCUMENTATION AND A DISCREPANCY BETWEEN COMMON TERMINOLOGY AND THE ICD].

INTRODUCTION: Hair tourniquet syndrome, AKA hair thread tourniquet or hair strangulation occurs among infants. A human hair or a thread strangulates a body appendage, resulting in obstruction of blood and lymph flow. If not recognized early it may cause tissue necrosis and rarely, require amputation. AIMS: Revealing the discrepancy between incidence and documentation in practice. Understanding the challenges standing in the way of the clinician while admitting a patient. METHODS: A retrospective study. The hospital's archive was searched for the period between the years 2008 to 2018. According to the ICD9 system this phenomenon is termed "external constriction caused by hair". Upon questioning, doctors had admitted having trouble finding the right diagnosis while digitally documenting a patient. The archive was searched twice - firstly, by the correct ICD9 code. Secondly, a general search was performed reviewing all 0-1 year-old patients' files. RESULTS: By researching the ICD9 code, 7 files were found. On the second search, 41 files were found, among them only 5 files were documented properly according to the ICD9 system. CONCLUSIONS: The majority (87.8%) of patients suffered from hair strangulation syndrome were not documented properly. Lack of documentation is a result of the digital difficulty finding the right diagnosis. DISCUSSION: Hair strangulation syndrome is not as rare as may be concluded basing on existing data. Clinicians must include it in the differential diagnosis when admitting a patient with the relevant symptoms or an agitated infant with no clear cause. Adjusting the digital systems in Israeli hospitals should be considered.

Effect of Electrode Shape and Flow Conditions on the Electrochemical Detection with Band Microelectrodes.

In this work, we report the analysis of the electrochemical detection of electroactive species with band microelectrodes that operate under controlled convection. The study focuses on the determination of the collection efficiency of the analyte as a function of inlet flow velocity and microband geometry (inlaid, bumped and recessed), also providing a straightforward method for the theoretical determination of the lower detection limit. The analysis has been carried out by simulating the dimensionless mass transport with the finite element method, delivering the stationary limiting current density. Simulations have been performed on systems consisting of single and double band electrodes to investigate the trail effect on the electrochemical detection. We show that the obtained dimensionless results can be easily turned into dimensional data, providing a tool for the design of devices. The proposed method is general and can easily be extended to systems with different geometry.

Spectroscopic Characterization of Natural Melanin from a Streptomyces cyaneofuscatus Strain and Comparison with Melanin Enzymatically Synthesized by Tyrosinase and Laccase.

An actinobacteria strain was isolated from Algerian Sahara soil and assigned to Streptomyces cyaneofuscatus Pridham et al. 1958 species. This strain was selected for its ability to produce melanin exopigments in liquid and solid media. Melanin synthesis was associated with tyrosinase activity and the enzyme from this strain was isolated and biochemically characterized. Synthetic melanin was then enzymatically produced using the S. cyaneofuscatus Pridham et al. 1958 tyrosinase. As this enzyme showed a higher diphenolase activity, a synthetic melanin from the enzymic oxidation of 3,4-dihydroxyphenylalanine (dopa) was obtained by the use of a Trametes versicolor (L.) Lloyd laccase for comparison. The natural and synthetic pigments were physico-chemically characterized by the use of ultraviolet (UV)-Visible, and Fourier transform infrared (FT-IR) and multifrequency electron paramagnetic resonance (EPR) spectroscopies. All the melanin samples displayed a stable free radical when analyzed by X-band EPR spectroscopy. Once the samples were recorded at Q-band EPR, a copolymer derived from a mixture of different constituents was evident in the natural melanin. All radical species were analyzed and discussed. The use of water-soluble melanin naturally produced by S. cyaneofuscatus Pridham et al. 1958 represents a new biotechnological alternative to commercial insoluble pigments.

Paramagnetism and Relaxation Dynamics in Melanin Biomaterials.

Spectroscopical characterization of melanins is a prior requirement for the efficient tailoring of their radical scavenging, ultraviolet-visible radiation absorption, metal chelation, and natural pigment properties. Electron paramagnetic resonance (EPR), exploiting the common persistent paramagnetism of melanins, represents the elective standard for the structural and dynamical characterization of their constituting radical species. Although melanins are mainly investigated using X-band (9.5 GHz) continuous wave (CW)-EPR, an integration with the application of Q-band (34 GHz) in CW and pulse EPR for the discrimination of melanin pigments of different compositions is presented here. The longitudinal relaxation times measured highlight faster relaxation rates for cysteinyldopa melanin, compared to those of the most common dopa melanin pigment, suggesting pulse EPR spin-lattice relaxation time measurements as a complementary tool for characterization of pigments of interest for biomimetic materials engineering.

Analysis of mass transport in ionic liquids: a rotating disk electrode approach.

Ionic Liquids are a promising alternative to water electrolytes for the electrodeposition of metals. These solvents have a much larger electrochemical window than water that expands the potential of electrodeposition. However, mass transport in Ionic Liquids is slow. The slow mass transport dramatically affects the rate of reactions at the solid-liquid interface, hampering the exploitation of Ionic Liquids in high-throughput electrodeposition processes. In this paper, we clarify the origin of such poor mass transport in the diffusion-advection (convection) regime. To determine the extent and the dynamics of the convection boundary layers, we performed Rotating Disk Electrode (RDE) experiments on model reactions along with the finite element simulation. Both the experiments and the finite element modelling showed the occurrence of peaks in the RDE curves even at relatively high rotation rates (up to 2000 rpm). The peak in the RDE is the fingerprint of partial diffusion control that happens for the relative extent of the diffusion and convection boundary layers. In looking for a close match between the experiments and the simulations, we found that the ohmic drop plays a critical role and must be considered in the calculation to find the best match with the experimental data. In the end, we have shown that the combined approach consisting of RDE experiments and finite elements modelling providing a tool to unravel of the structure of the diffusion and convection boundary layers both in dynamic and stationary conditions.