Non-invasive method for assessment of inflammation.

This article explores the potential of non-invasive measurement for elevated levels of erythrocyte aggregation in vivo, which have been correlated with a higher risk of inflammatory processes. The study proposes utilizing a dynamic light scattering approach to measure aggregability. The sensor modules, referred to as "mDLS," comprise VCSEL and two photodiodes. Two of these modules are placed on an inflatable transparent cuff, which is then fitted to the subject's finger root, with one sensor module positioned on each side. By temporarily halting blood flow for one minute using over-systolic inflation of the cuff, signals from both sensors are recorded. The study involved three distinct groups of subjects: a control group consisting of 65 individuals, a group of 29 hospitalized COVID-19 patients, and a group of 34 hospitalized patients with inflammatory diseases. Through experimental results, significant differences in signal kinetic behavior were observed between the control group and the two other groups. These differences were attributed to the rate of red blood cell (RBC) aggregation, which is closely associated with inflammation. Overall, the study emphasizes the potential of non-invasive diagnostic tools in evaluating inflammatory processes by analyzing RBC aggregation.

Scattering-driven PPG signal model.

This article discusses the origin of PPG signals. Two plausible hypotheses are analyzed: the volumetric hypothesis and a model wherein the PPG is driven by the RBC aggregation process. To verify the model predictions, the PPG signals at the fingertip were measured. External pressure was applied to the fingertip, presumably reducing the blood flow. The results expressed in terms of gamma, used in pulse-oximetry, agree with the aggregation model. In addition, the oscillometric signal and the PPG signal amplitude were simultaneously measured in the fingertip. All of the experimental results favor the proposed aggregation mechanism as responsible the PPG signal.

[The role of «Youth and aging proteins¼ in essential hypertension pathogenesis.]

Essential hypertension (EG) is an age-associated disease. Often EG of elderly patients haven't good way of treatment. Thus, the search of new target molecules for EG therapy is an actual goal of gerontology and molecular medicine. It was shown, that during EG concentrations of GDF11 «youth protein¼ decreased in 3,3 times and GDF15, JAM-A/1, CCL11 «aging proteins¼ increased in 1,4-2,4 times. EG patients have abnormal microcirculation processes. It was shown as decreasing in 1,3 and 1,7 times of hemodynamic HI1 and H1-H3 indexes. EG patients have negative correlation of GDF15 concentration with arterial pressure. EG patients have no correlation of JAM-A/1 concentration with arterial pressure. Normal is positive correlation with GDF15, JAM-A/1 concentration with arterial pressure. GDF15 blood level during EG have positive correlation with HI1-HI3 and negative correlation with NEUR_HI2 and MAYER_HI3 indexes. It can show on pathogenesis mechanisms of endothelial and smooth muscles function of vessels tissues. We suppose, that the regulation of GDF11, GDF15, JAM-A/1, CCL11 «youth and aging proteins¼ can be target object of EG therapy.

Impact of Fitness Status on the Optically Measured Hemodynamic Indexes.

The physiological characteristics of skin blood flow can be described in terms of the hemodynamic indices (HI). The HI is derived from the laser speckle characteristics, which are governed by the cutaneous blood flow. A miniaturized dynamic light-scattering sensor was used to measure the speckle pattern from the finger root. Three groups of subjects from 15 to 25 years of age were tested. The first group included subjects who are actively engaged in sport activities; the second group included subjects with low level of physical activity; and the third group included healthy controls with moderate physical activity. The HI parameters were measured prior to and after the performance of a determined physical load. As a marker of cardiovascular fitness (CVF), we used the postload decay rate of HI. We found that the hemodynamic response to the physical load provides a statistically significant correlation with the postload heart rate decay. It was also found that postocclusion increase of the arterial HI is more prominent in the group with higher physical activity. These results indicate that hemodynamic indices can be used as an additional marker for cardiovascular fitness level.

Minimally invasive external mini-glaucoma shunt implantation without conjunctival dissection.

The current method for implantation of the Ex-PRESS Glaucoma Filtration Device requires a conjunctival peritomy and shunt insertion under the guarded protection of a scleral flap. This technique requires suture closure of the flap and conjunctiva. A new minimally invasive technique for Ex-PRESS shunt implantation allows for insertion through a scleral tunnel originating from a grooved clear corneal incision. This new method avoids the need for conjunctival dissection and closure and offers the advantages of eliminating conjunctival wound leaks while maintaining the protection of a partial thickness scleral covering. This new technique may offer a faster safer means for shunt implantation with the potential for less conjunctival scarring.

Neurochemical changes within human early blind occipital cortex.

Early blindness results in occipital cortex neurons responding to a wide range of auditory and tactile stimuli. These changes in tuning properties are accompanied by an extensive reorganization of the occipital cortex that includes alterations in anatomical structure, neurochemical and metabolic pathways. Although it has been established in animal models that neurochemical pathways are heavily affected by early visual deprivation, the effects of blindness on these pathways in humans is still not well characterized. Here, using (1)H magnetic resonance spectroscopy in nine early blind and normally sighted subjects, we find that early blindness is associated with higher levels of creatine, choline and myo-Inositol and indications of lower levels of GABA within the occipital cortex. These results suggest that the cross-modal responses associated with early blindness may, at least in part, be driven by changes within occipital biochemical pathways.

Post-laser assisted in situ keratomileusis epithelial ingrowth and its relation to pretreatment refractive error.

PURPOSE: To assess the incidence of epithelial ingrowth after laser in situ keratomileusis and its correlation with myopic or hyperopic treatment. METHODS: This retrospective study analyzed 1000 consecutive LASIK procedures performed by 3 surgeons using identical surgical technique with a Hansatome microkeratome. Eyes that developed epithelial ingrowth were evaluated using the Machat grading system. Patients were subdivided into 2 groups (myopic or hyperopic) based on the preoperative refractive error. RESULTS: The total incidence of epithelial ingrowth was 4.7%. The incidence after primary treatment was 3.9%. The incidence after enhancement was 12.8%. The total incidence of epithelial ingrowth was 3% in the myopic group compared with 23% in the hyperopic group. After primary myopic treatment, there was a 3% incidence of epithelial ingrowth compared with 17% after primary hyperopic treatment. The incidence after enhancement was 7% in the myopic group and 43% in the hyperopic group. CONCLUSIONS: Patients undergoing hyperopic laser in situ keratomileusis have a greater incidence of epithelial ingrowth than those undergoing myopic treatment. In addition, enhancement procedures have a higher incidence than primary procedures.

A noninvasive method of examination of the hemostasis system.

We propose a noninvasive method of in vivo examination the hemostasis system based on speckle pattern analysis of coherent light scattering from the skin. We compared the results of measuring basic blood coagulation parameters by conventional invasive and noninvasive methods. A strict correlation was found between the results of measurement of soluble fibrin monomer complexes, international normalized ratio (INR), prothrombin index, and protein C content. The noninvasive method of examination of the hemostatic system enable rough evaluation of the intensity of the intravascular coagulation and correction of the dose of indirect anticoagulants maintaining desired values of INR or prothrombin index.

Topographic organization of V1 projections through the corpus callosum in humans.

The visual cortex in each hemisphere is linked to the opposite hemisphere by axonal projections that pass through the splenium of the corpus callosum. Visual-callosal connections in humans and macaques are found along the V1/V2 border where the vertical meridian is represented. Here we identify the topography of V1 vertical midline projections through the splenium within six human subjects with normal vision using diffusion-weighted MR imaging and probabilistic diffusion tractography. Tractography seed points within the splenium were classified according to their estimated connectivity profiles to topographic subregions of V1, as defined by functional retinotopic mapping. First, we report a ventral-dorsal mapping within the splenium with fibers from ventral V1 (representing the upper visual field) projecting to the inferior-anterior corner of the splenium and fibers from dorsal V1 (representing the lower visual field) projecting to the superior-posterior end. Second, we also report an eccentricity gradient of projections from foveal-to-peripheral V1 subregions running in the anterior-superior to posterior-inferior direction, orthogonal to the dorsal-ventral mapping. These results confirm and add to a previous diffusion MRI study (Dougherty et al., 2005) which identified a dorsal/ventral mapping of human splenial fibers. These findings yield a more detailed view of the structural organization of the splenium than previously reported and offer new opportunities to study structural plasticity in the visual system.

Primary anterior chamber intraocular lens for the treatment of severe crystalline lens subluxation.

Subluxated cataractous and clear lenses are commonly treated by limbal or pars plana lensectomy followed by primary or secondary intraocular lens (IOL) implantation. Adjunctive capsular prosthetic devices have facilitated lens removal and IOL centration in these challenging cases but have also added complexity and potential complications to the procedure. Although crystalline lens extraction may be required to clear the visual axis in mild to moderate lens subluxations, we propose insertion of a primary anterior chamber IOL without lens extraction in severe subluxations when the eye is optically aphakic or can be made functionally aphakic following neodymium:YAG laser zonulysis. Two cases demonstrating this approach are presented.

Aspheric intraocular lens selection based on corneal wavefront.

PURPOSE: To determine the feasibility of selectively targeting zero total postoperative spherical aberration by selecting the best fit aspheric intraocular lens (IOL) based on preoperative topographically derived corneal spherical aberration. METHODS: Candidates for cataract surgery were offered selection of aspheric IOLs based on corneal spherical aberration. The target postoperative total wavefront spherical aberration Z4,0 was set at zero. Corneal topographic spherical aberration Z4,0 was measured at the 6-mm optical zone, and one of three aspheric IOLs was chosen so the arithmetic sum of the corneal spherical aberration and pseudophakic spherical aberration came closest to zero. Postoperatively, total ocular wavefront was measured and statistical analysis performed to ascertain the accuracy of customized aspheric IOL selection. RESULTS: Thirty eyes of 18 patients were available for analysis. The SofPort Advanced Optics (Bausch & Lomb) lens was implanted in 1 eye, the AcrySof IQ (Alcon Laboratories Inc) in 11 eyes, and the Tecnis Z9000 or Z9002 (Advanced Medical Optics [AMO]) in 18 eyes. Total postoperative ocular spherical aberration for the entire population measured -0.013+/-0.072 microm (SofPort: +0.025 microm; AcrySof IQ: +0.010+/-0.053 microm; and Tecnis: -0.015+/-0.052 microm [P=.22]). For the entire population, mean absolute predictive error measured 0.058+/-0.056 microm (SofPort: 0.040 microm; AcrySof IQ: 0.052+/-0.040 microm; and Tecnis: 0.063+/-0.066 microm [P=.631). CONCLUSIONS: Customized selection of aspheric IOLs based on corneal wavefront is feasible and produces favorable results compared with studies of unselected patient populations implanted with aspheric IOLs.

Persistent interface fluid syndrome.

We present an unusual case of persistent interface fluid that would not resolve despite normal intraocular pressure and corneal endothelial replacement with Descemet-stripping endothelial keratoplasty. Dissection, elevation, and repositioning of the laser in situ keratomileusis flap were required to resolve the interface fluid. Circumferential corneal graft-host margin scar formation acting as a mechanical strut may have been the cause of the intractable interface fluid.

In vivo dynamic light scattering microscopy of tumour blood vessels.

We present a study investigating the use of dynamic light scattering microscopy based on the temporal laser speckle's contrast that is produced over time by red blood cells (RBCs) flowing inside tumour blood vessels. The proposed noninvasive methodology is capable of producing high-resolution images of tumour vasculature. The technique is effective at producing images from tissue at a significant depth, as well as potentially having the ability to monitor tumour perfusion. An advantage of this methodology is that it has improved depth penetration compared with conventional imaging techniques (such as reflected-light microscopy), and one can avoid the use of any fluorescent or artificial chemicals for labeling. This is advantageous since labeling materials can affect imaging and animal welfare with respect to experiments that require continuous and repetitive monitoring.

Comparison of surgically induced astigmatisms after clear corneal incisions of different sizes.

PURPOSE: This study was performed to assess efficiency and stability of astigmatic change by incision size after cataract surgery. METHODS: This work was designed as a retrospective, comparative, nonrandomized interventional study. A total of 121 cases of cataract surgery were reviewed in 98 patients performed by one surgeon at the Oregon Eye Institute in Eugene, OR, USA with 3-year follow-ups. All procedures were performed with the temporal approach of self-sealing incisions. The serial change in surgically induced astigmatisms were examined in all cases of three groups: Group A, cartridge injection of a foldable IOL through a 2.5 mm self-sealing incision; Group B, cartridge injection of a foldable IOL through a 3.0 mm self-sealing incision; Group C, cartridge injection of a foldable IOL through a 3.5 mm self-sealing incision. Keratometric data were obtained preoperatively, and 3 weeks, 3 months, 6 months, 9 months, 12 months, 24 months and 36 months postoperatively. Polar value analysis was performed to calculate the surgically induced astigmatism. RESULTS: The astigmatic change decreased over time in Group B (P<0.05). The other groups tended to remain in induced astigmatism. All groups showed anticlockwise torque at 3 weeks following surgery. Group B showed a decrease in deviation, but the other groups showed increases in their torque value at postoperative 12 months (P<0.05). CONCLUSIONS: The 3.0 mm incision size correlated with the least surgically induced astigmatism.