Dehydration of a diver during a hyperbaric chamber exposure with oxygen decompression.

Objective: An analysis of factors that may indicate both the type and degree of dehydration of a diver's body following a dry chamber hyperbaric exposure. Methods: The study was participated by 63 men - professional divers, with extensive diving experience, aged 24-51 years (average age 32.6). The subjects underwent two hyperbaric exposures, one to a pressure of 0.3 MPa and one to a pressure of 0.6 MPa, with oxygen decompression. The exposures were carried out in a hyperbaric chamber pursuant to the decompression tables of the Polish Navy, with the observance of a 24-hour interval between exposures. Blood samples were collected from the participants in order to perform a blood morphology test. Body weight was measured with the bioelectrical impedance method using the Maltron BioScan 920 device.The results were subjected to statistical analysis. The following blood morphology parameters were analyzed: hematocrit (Ht), erythrocyte size (MCV), color index (MCHC) and body weight composition: total water (TBW), extracellular water (ECW), intracellular water (ICW). Results: The studies have shown that during a hyperbaric exposure in the chamber the diver's body becomes dehydrated, with observable loss of both intracellular water as evidenced by the reduction of hematocrit content and erythrocyte size, as well as extracellular water, with the accompanying increase in the color index. Conclusions: Hyperbaric conditions are conducive to the dehydration of the diver's body, however to a degree which does not lead to an occurrence of health hazards. Good care for one's health through proper nutrition and hydration are sufficient preventive and protective measures.

Influence of exposure in hyperbaric chambers on selected parametersof oxidative stress in professional divers.

PURPOSE: This study evaluated the influence of hyperbaric exposure chambers on selected parameters of oxidative stress in divers' blood. METHODS: 25 healthy men (non-smoking experienced divers) ages 18-40 took part in the experiment. Subjects were exposed to hyperbaric conditions similar to those at 30 meters of depth while diving. A control group consisted of 20 healthy men who have never dived or been exposed to hyperbaric conditions. Blood was drawn from the cubital vein after overnight fasting. Superoxide dismutase (SOD-1) activity and malondialdehyde (MDA) concentration were marked in red blood cells (RBCs), carbonyl group concentration marked in serum proteins, and nitrate/nitrite concentrations were estimated in plasma. RESULTS: Statistically significant differences were found between the divers and the control group in MDA concentration in erythrocytes and carbonyl group concentration in serum proteins. Nitrite/nitrate concentrations in plasma plus SOD-1 activity in RBCs decreased significantly in the diver group compared with the control group. After hyperbaric exposure MDA concentration in erythrocytes increased considerably in the test group and a significant increase in SOD-1 activity was observed. A significant increase of nitrite/nitrate concentration was noted in plasma as well as an increase in the carbonyl group in serum proteins. CONCLUSION: Considerably weak enzymatic antioxidative defense was observed in the RBCs of individuals exposed to hyperbaric pressures versus those in normobary. This issue indicates that a diver's system has a larger susceptibility for negative effects from oxidative stress. The results also indicate that hyperbaric conditions can intensify reactions via free radicals.

THE EFFECT OF BACKGROUND SIGNAL AND ITS REPRESENTATION IN DECONVOLUTION OF EPR SPECTRA ON ACCURACY OF EPR DOSIMETRY IN BONE.

This study is about the accuracy of EPR dosimetry in bones based on deconvolution of the experimental spectra into the background (BG) and the radiation-induced signal (RIS) components. The model RIS's were represented by EPR spectra from irradiated enamel or bone powder; the model BG signals by EPR spectra of unirradiated bone samples or by simulated spectra. Samples of compact and trabecular bones were irradiated in the 30-270 Gy range and the intensities of their RIS's were calculated using various combinations of those benchmark spectra. The relationships between the dose and the RIS were linear (R2 > 0.995), with practically no difference between results obtained when using signals from irradiated enamel or bone as the model RIS. Use of different experimental spectra for the model BG resulted in variations in intercepts of the dose-RIS calibration lines, leading to systematic errors in reconstructed doses, in particular for high- BG samples of trabecular bone. These errors were reduced when simulated spectra instead of the experimental ones were used as the benchmark BG signal in the applied deconvolution procedures.

Experimental modeling of pulmonary barotrauma.

The main causes of pulmonary barotrauma include loss of consciousness or panic attack of a diver and emergence from underwater with a constricted glottis. However, numerous publications and our observations indicate that the majority of fully symptomatic cases of pulmonary barotrauma develop without any evident errors in the ascending technique. Therefore, an attempt was made to examine such cases using the experimental model of pulmonary barotrauma designed by the authors. The experiment was conducted on 32 rabbits divided into three groups: Group C--not subjected to any treatment; Group E--with induced pulmonary barotrauma; and Group CT--subjected only to compression followed by quick decompression. In Groups E and CT, the same morphological markers of pulmonary barotrauma were detected in the lungs, although their severity varied. Morphological markers of pulmonary barotrauma were observed both in the group where the tube was not ob-structed (E) and in animals exposed only to rapid decompression (CT)

Presence of lymphatics in a rat tendon lesion model.

Tendons lack sufficient blood supply and represent a bradytroph tissue with prolonged healing time under pathological conditions. While the role of lymphatics in wound/defect healing in tissues with regular blood supply is well investigated, its involvement in tendon defects is not clear. We here try to identify the role of the lymphatic system in a tendon lesion model with morphological methods. A rat Achilles tendon lesion model (n = 5) was created via surgical intervention. Two weeks after surgery, animals were killed and lesioned site removed and prepared for polarization microscopy (picrosirius red) and immunohistochemistry using the lymphatic markers PROX1, VEGFR3, CCL21, LYVE-1, PDPN, and the vascular marker CD31. Additionally, DAPI was applied. Untreated tendons served as controls, confocal laser-scanning microscopy was used for documentation. At the lesion site, polarization microscopy revealed a structural reintegration while immunohistochemistry detected band-like profiles immunoreactive for PDPN, VEGFR3, CCL21, LYVE1, and CD31, surrounding DAPI-positive nuclei. PROX1-positive nuclei were detected within the lesion forming lines and opposed to each other. These PROX1-positive nuclei were surrounded by LYVE-1- or VEGFR3-positive surfaces. Few CD31-positive profiles contained PROX1-positive nuclei, while the majority of CD31-positive profiles lacked PROX1-positive nuclei. VEGFR3-, PDPN-, and LYVE-1-positive profiles were numerous within the lesion site, but absent in control tissue. Within 2 weeks, a structural rearrangement takes place in this lesion model, with dense lymphatic supply. The role of lymphatics in tendon wound healing is unclear, and proposed model represents a good possibility to study healing dynamics and lymphangiogenesis in a tissue almost completely lacking lymphatics in physiological conditions.

Risk factors increasing health hazards after air dives.

The aim of the present study was to determine the effect of postprandial hypertriglyceridemia on the risk of decompression stress following hyperbaric air exposures. The study involved 55 male individuals aged 20-48 years (31.47 ± 5.49 years), body mass index 20.3-33.2 kg/m2 (25.5 ± 2.58 kg/m2). Blood was sampled two hours after a meal each participant had in accordance with individual dietary preferences to determine the following parameters: blood cell counts, activity of aspartate aminotransferase (AST) and alanine ammotransterase (ALT), concentrations of total cholesterol and triglycerides. After each hyperbaric exposure, the presence and intensity of decompression stress were assessed using the Doppler method. Decompression stress was found in 30 individuals. Postprandial hypertriglyceridemia and hypercholesterolemia increased the risk of decompression stress after hyperbaric air exposures.

Alarin in cranial autonomic ganglia of human and rat.

Extrinsic and intrinsic sources of the autonomic nervous system contribute to choroidal innervation, thus being responsible for the control of choroidal blood flow, aqueous humor production or intraocular pressure. Neuropeptides are involved in this autonomic control, and amongst those, alarin has been recently introduced. While alarin is present in intrinsic choroidal neurons, it is not clear if these are the only source of neuronal alarin in the choroid. Therefore, we here screened for the presence of alarin in human cranial autonomic ganglia, and also in rat, a species lacking intrinsic choroidal innervation. Cranial autonomic ganglia (i.e., ciliary, CIL; pterygopalatine, PPG; superior cervical, SCG; trigeminal ganglion, TRI) of human and rat were prepared for immunohistochemistry against murine and human alarin, respectively. Additionally, double staining experiments for alarin and choline acetyltransferase (ChAT), tyrosine hydroxilase (TH), substance P (SP) were performed in human and rat ganglia for unequivocal identification of ganglia. For documentation, confocal laser scanning microscopy was used, while quantitative RT-PCR was applied to confirm immunohistochemical data and to detect alarin mRNA expression. In humans, alarin-like immunoreactivity (alarin-LI) was detected in intrinsic neurons and nerve fibers of the choroidal stroma, but was lacking in CIL, PPG, SCG and TRI. In rat, alarin-LI was detected in only a minority of cranial autonomic ganglia (CIL: 3.5%; PPG: 0.4%; SCG: 1.9%; TRI: 1%). qRT-PCR confirmed the low expression level of alarin mRNA in rat ganglia. Since alarin-LI was absent in human cranial autonomic ganglia, and only present in few neurons of rat cranial autonomic ganglia, we consider it of low impact in extrinsic ocular innervation in those species. Nevertheless, it seems important for intrinsic choroidal innervation in humans, where it could serve as intrinsic choroidal marker.

Effects of water treatment and sample granularity on radiation sensitivity and stability of EPR signals in X-ray irradiated bone samples.

The article describes effects of sample conditions during its irradiation and electron paramagnetic resonance (EPR) measurements on the background (BG) and dosimetric EPR signals in bone. Intensity of the BG signal increased up to two to three times after crushing of bone to sub-millimetre grains. Immersion of samples in water caused about 50 % drop in intensity of the BG component followed by its regrowth in 1-2 months. Irradiation of bone samples produced an axial dosimetric EPR signal (radiation-induced signal) attributed to hydroxyapatite component of bone. This signal was stable and was not affected by water. In samples irradiated in dry conditions, EPR signal similar to the native BG was also generated by radiation. In samples irradiated in wet conditions, this BG-like component was initially much smaller than in bone irradiated as dry, but increased in time, reaching similar levels as in dry-irradiated samples. It is concluded that accuracy of EPR dosimetry in bones can be improved, if calibration of the samples is done by their irradiations in wet conditions.

Neural crest origin of retinal and choroidal pericytes.

PURPOSE: The origin of pericytes (PCs) has been controversially discussed and at least three different sources of PCs are proposed: a neural crest, mesodermal, or bone marrow origin. In the present study we investigated a potential neural crest origin of ocular PCs in a transgenic Rosa26-YFP-Sox10-Cre neural crest-specific reporter mouse model at different developmental stages. METHODS: The Rosa26-YFP-Sox10-Cre mouse model expresses the yellow fluorescent protein (YFP) reporter in cells with an active Sox10 promoter and was here used for cell fate studies of Sox10-positive neural crest derived progeny cells. Detection of the YFP signal in combination with double and triple immunohistochemistry of chondroitin sulfate proteoglycan (NG2), platelet derived growth factor receptor ß (PDGFRß), α smooth muscle actin (αSMA), oligodendrocyte transcription factor 2 (Olig2), and lectin was performed and analyzed by confocal microscopy. RESULTS: Sox10-YFP-positive cells and profiles were detected in the inner nuclear layer, the ganglionic cell layer, and the axons of the nerve fiber layer in postnatal retinas. An additional population has been identified in the retina, optic nerve, and choroid that displays strong perivascular localization. These cells were colocalized with the PC-specific markers NG2 and PDGFRß in embryonic (E14.5) as well as postnatal (P4, P12, 6-week-old) vasculature. Beside PCs, vascular smooth muscle cells (vSMCs) were also labeled by the Sox10-YFP reporter protein in all ocular tissues investigated. CONCLUSIONS: Since YFP-positive PCs and vSMCs are colocalized with NG2 and PDGFRß, we propose that capillary PCs and vSMCs in the retina and the optic nerve, both parts of the central nervous system, as well as in the choroid, a tissue of mesodermal origin, derive from the neural crest.

A new nanosecond UV laser at 355 nm: early results of corneal flap cutting in a rabbit model.

PURPOSE: A new 355 nm UV laser was used for corneal flap cutting in an animal model and tested for clinical and morphologic alterations. METHODS: Corneal flaps were created (Chinchilla Bastards; n = 25) with an UV nanosecond laser at 355 nm (150 kHz, pulse duration 850 ps, spot-size 1 µm, spot spacing 6 × 6 µm, side cut Δz 1 µm; cutting depth 130 µm) and pulse energies of 2.2 or 2.5 µJ, respectively. Following slit-lamp examination, animals were killed at 6, 12, and 24 hours after treatment. Corneas were prepared for histology (hematoxylin and eosin [HE], TUNEL-assay) and evaluated statistically, followed by ultrastructural investigations. RESULTS: Laser treatment was tolerated well, flap lift was easier at 2.5 µJ compared with 2.2 µJ. Standard HE at 24 hours revealed intact epithelium in the horizontal cut, with similar increase in corneal thickness at both energies. Irrespective of energy levels, TUNEL assay revealed comparable numbers of apoptotic cells in the horizontal and vertical cut at 6, 12, and 24 hours, becoming detectable in the horizontal cut as an acellular stromal band at 24 hours. Ultrastructural analysis revealed regular morphology in the epi- and endothelium, while in the stroma, disorganized collagen lamellae were detectable representing the horizontal cut, again irrespective of energy levels applied. CONCLUSIONS: This new UV laser revealed no epi- nor endothelial damage at energies feasible for corneal flap cutting. Observed corneal swelling was lower compared with existing UV laser studies, albeit total energy applied here was much higher. Observed loss of stromal keratinocytes is comparable with available laser systems. Therefore, this new laser is suitable for refractive surgery, awaiting its test in a chronic environment.

The influence of high-fat diets on the occurrence of decompression stress after air dives.

INTRODUCTION: In hyperbaric air exposures, the diver's body is subjected to an increased gas pressure, which simulates a real dive performed in water with the presence of hydrostatic pressure. The hyperbaric effect depends on pressure, its dynamics and exposure time. During compression, physical dissolution of inert gas in body fluids and tissues takes place. The decompression process should result in safe physiological disposal of excess gas from the body. However, despite the correct application of decompression tables we observe cases of decompression sickness. The study aim was to find factors affecting the safety of diving, with a particular emphasis on the diet, which thus far has not been taken into account. METHODS: The study subjects were 56 divers. Before hyperbaric exposure, the following data were collected: age, height and weight; plus each divers filled out a questionnaire about their diet. The data from the questionnaires allowed us to calculate the approximate fat intake with the daily food for each diver. Moreover, blood samples were collected from each diver for analysis of cholesterol and triglycerides. Hyperbaric exposures corresponded to dives conducted to depths of 30 and 60 meters. After exposures each diver was examined via the Doppler method to determine the possible presence of microbubbles in the venous blood. RESULTS AND DISCUSSION: Decompression stress was observed in 29 subjects. A high-fat diet has a direct impact on increasing levels of cholesterol and triglycerides in the blood serum. A high-fat diet significantly increases the severity of decompression stress in hyperbaric air exposures and creates a threat of pressure disease.