The relationship between optic disc-foveal distance with choroidal and retinal nerve fiber thickness.

BACKGROUND: The optic disc-foveal distance is very important as it is an anatomical measure of the fundus. As this distance increases and the fundus tension, there may be variability in retinal and choroidal thickness. The aim of this study was to determine the relationship between optic disc-foveal distance and choroidal and retinal nerve fiber thickness in healthy subjects. MATERIALS AND METHODS: A total of 72 people between the ages of 20-36 participated in the study. Optic disc-foveal distance was measured with a fundus camera and choroidal and retinal nerve fiber thicknesses were measured with an OCT (Optical coherence tomography) device. Littmann's formula (t = p × q × s) as modified by Bennett was applied to correct the magnification at the fundus camera imaging stage. RESULTS: The thickness of the nasal choroid (p=0.005; p=0.006), subfoveal choroid (p=0.004; p < 0.001) and temporal choroid (p=0.001; p=0.001) layers decreased as the DFD (Optic disc-to-foveal distance) increased in both right and left eyes of the individuals participating in the study, which was statistically significant. In addition, it was observed that the RNLF (Retinal nerve fiber layer) increased as the DFD distance increased, but this was not statistically significant. CONCLUSION: This study demonstrated that the optic disc-foveal distance, an anatomical measure of the fundus, does not affect RNLF in young and healthy subjects, but choroidal thickness does.

The relationship between sphenoidal sinus and sella turcica morphometry in the Turkish population: a retrospective study.

PURPOSE: The anatomical position of the sphenoidal sinus (SS) is very important for neurosurgeons because of the transsphenoidal approach to the pituitary gland. Therefore, the aim of this study was to determine the volume and shape of the SS and its relationship with the morphometry of the sella turcica. METHODS: This study included CT images of 282 males and 258 females with a mean age of 50.52 years (range 18-75) who underwent head CT. The morphometric values of the sella turcica and the volume of the SS were measured on the included radiologic images. Measurements were made on the sagittal slice closest to the midline in T1 sequence. Morphometric measurements were made with Micro Dicom Viewers software program and volume measurements were made with ITK SNAP software program. RESULTS: In this study, 4 types of SS shapes were obtained in the whole population: amorphous, pentagonal, triangular and quadrilateral. The mean SS volume was 7055.88 mm3 in males and 5694.48 mm3 in females and a statistically significant difference was observed (p < 0.001). In addition, a statistically significant difference was found between the sexes in the width and surface area parameters of the sella turcica (p < 0.05). CONCLUSION: In this study, the morphometric relationship between the shape of the sinus sphenoidale and sella turcica was demonstrated between men and women. In particular, the shape of the sinus sphenoidale was found to be anthropometrically different between men and women in the Turkish population. It is hypothesised that the data obtained in our study will guide surgeons performing transsphenoidal approach.

Evaluation of Autografts Used in Anterior Cruciate Ligament Reconstruction in Terms of Tensile Strength.

Introduction Anterior cruciate ligament (ACL) injuries increase the likelihood of chronic knee problems in later years, including early onset osteoarthritis. Therefore, ACL treatment is important in preventing knee problems from developing. The treatment of choice for ACL tears is surgery (ACL reconstruction), and the most popular tendons for ACL reconstruction are the patellar tendon, hamstring tendon (semitendinosus and gracilis tendons), and bone-patellar tendon-bone. The present study compares the tensile strength of autografts used in ACL reconstruction to identify the optimum autograft for ACL in terms of mechanical properties. Methods Cadavers were dissected, and the Achilles tendons, quadriceps tendons, hamstring tendons (semitendinosus and gracilis tendons), patellar tendon grafts, and ACLs were harvested. Tensile tests of each tendon graft were performed using a Shimadzu Autograph AG-IS 100 kN tester (Shimadzu, Kyoto, Japan). Results The mean difference in tensile strength between ACL and other grafts was lowest for the quadriceps in both males and females (p ˂ 0.001), meaning that ACL and quadriceps grafts are more compatible than other tendon grafts in terms of tensile strength. Conclusion The present study found the lowest mean difference in tensile strength to be between the ACL and the quadriceps tendon, suggesting that the use of the quadriceps tendon in ACL reconstruction will yield more positive outcomes.

Repeated use of fibrin sealants kept at room temperature in conjunctival autografting: An animal study.

Purpose: In this study, our aim was to investigate if fibrin adhesives used in conjunctival wound surgery with autologous conjunctival grafts could be used repeatedly at different times after surgical opening. Methods: 40 New Zealand rabbits were used in the study. These animals were divided into four groups, each consisting of 10 rabbits, and hence 20 eyes. In the first group (control group), Tisseel fibrin sealant was used on the day the eye was first opened surgically; in the second group, it was used on the seventh day; on the third group, it was used on the 14th day; and in the fourth group, it was used 28 days after surgical opening. The graft from the inferior bulbar conjunctiva was attached using Tisseel fibrin glue to the superior scleral bed at the location where the superior bulbar conjunctiva was excised in the same eye. Results: No microbial growth was detected in the cultures of the samples tested. There were two partial graft loss in group 2 and there was one partial graft loss in each group of the other groups, and further total graft loss was present in one rabbit in group 3. None of the rabbits had any complications like granuloma, Corneal dellen or infection. Conclusion: Based on these results, fibrin sealants can be used repeatedly by storing them at room temperature. Repeated use of fibrin adhesives will reduce the cost of ophthalmologic surgeries and non-ophthalmologic surgeries.

A new technique for preparing cadavers using PMMA: Rat and mouse example.

BACKGROUND: Polymethyl methacrylate is a member of the acrylic polymer family with superior optical properties. It is used in dentistry, hospital incubators, lenses, and various surgical fields, especially orthopedics. In this preliminary study, we aimed to prepare cadavers using the industrial form of polymethyl methacrylate. METHODS: The new technique consists of fixation, washing, purification, impregnation, and polymerization. For the study, two whole rat bodies, two rat front legs and two rat hind legs, one half rat body, two whole mouse bodies, and all internal organs were used. Wistar albino rats and BALB/c mice were used. After the cadaver samples were fixed and washed, they were passed through an alcohol series starting from 50%, completing the purification process. In the next step, a solution was prepared by mixing 100 ml of Thinner into 1000 ml of a mixture containing styrene, methyl methacrylate, and Co(II)2-ethyl hexanoate. The samples were immersed in the solution under negative pressure (from 10 mmHg to 400 mmHg), allowing the samples to absorb the solution thoroughly. They were then treated with methyl ethyl ketone peroxide and the polymerization step was terminated. RESULTS: The cadaver samples obtained using polymer were hard, they maintained the given shape, and showed a relatively transparent quality. The production of these materials took 35 days, excluding fixation. The tissue samples were odorless in the process after polymerization. Also, there was no decay in the samples after the production stage and they could be stored under room conditions. CONCLUSION: This study determined that cadavers could be prepared using polymethyl methacrylate and methyl ethyl ketone peroxide. The polymer used here cost about $5. The cadavers can be safely exhibited in room conditions for five years without requiring special conditions like pools or cold storage. Further research should compare this technique with the plastination technique in terms of texture, color, weight, application time, and cost.

A new definition about the relationship of intercellular fluid in the brain with the mandibular and parotid lymph nodes.

This study was carried out to reveal the relationship of the brain with both the mandibular lymph node (MLN) and parotid lymph node (PLN) by the hyperspectral fluorescence imaging techniques of Qdot 800 (QD) nanoparticles using in vivo. This relationship of the brain with both lymph nodes offers the preliminary morphological definition of lymphatic drainage. QD was injected into the left parietal brain lobe of each rat at a depth of 2.50 mm. In 65% of the rats that were imaged in vivo, signals were received first from the right MLN and PLN, and then from the left MLN and PLN. In contrast, in two female rats, the first signal was received from the right PLN. There was no difference between the female and male rats overall. The most noteworthy finding of this study was that the tracer injected into the left parietal lobe reached the right mandibular and parotid lymph nodules earlier. This result indicates a different and unknown pathway in the brain that communicates with the lymph nodes. Moreover, this study shows that these lymph nodes pathways can be used in the treatment of diseases such as brain trauma, cerebral edema, and Alzheimer's disease (AD).

Origin and distribution of the brachial plexus of the Van cats.

Knowing the structure and variations of the plexus brachialis is important in neck and shoulder surgery. The knowledge of the brachial plexus reduces the injury rate of the nerves in surgical interventions to the axillary region. The major nerve trunks of the thoracic limb were the suprascapular, subscapular, axillary, radial, musculocutaneous, median and ulnar nerves. In Van cats, the brachial plexus was formed by the ventral branches of the spinal nerves, C6-C7-C8 and T1. The 7th cervical nerve was quite thick compared to the others. The subscapular nerve was the thinnest (on the right side, the average length was 6.55 ± 0.60 mm and on the left side was 6.50 ± 0.60 mm), and the radial nerve was the thickest (the average length on the right side was 28.48 ± 0.44 mm and on the left side was 29.11 ± 0.55 mm). The suprascapular nerve was formed by the ventral branch of the 6th cervical nerve. The subscapular nerves were formed by a branch originating from the 6th cervical nerve and the two medial and caudal branches originating from the 7th cervical nerve. No communicating branch between the ulnar nerve and the median nerve was observed in the palmar region. The axillary nerve was formed by the ventral branches of the 7th nerve, the musculocutaneous nerve was formed by ventral branches of the 6th and 7th cervical nerves, and the ulnar nerve was formed by ventral branches of the 8th cervical and the 1st thoracic nerves. The radial nerve was the thickest branch in the brachial plexus. In Van cats, the origin and distribution of nerves were similar to those reported in the literature for other species of cats, with the exception of the suprascapular, subscapular and axillary nerves.

Application of quantum dot-based biosensor to the conjunctiva in Wistar albino rats.

This study was conducted to get an idea about the distribution of the lymphatic fluid in conjunctiva throughout the body parts. For this purpose, Qdot655 (QD), fluorescence nanoparticles, spread onto the conjunctiva were used on Wistar albino rats. Drainage of QD particles from conjunctiva was followed up via fluorescence images at different hours on body parts such as eye, ears, forearms, hind legs and tails. The first fluorescence signals within the 30th minutes following administration of QD were observed in the nasal region and the anterior extremities. Whereas within 60th minutes following QD spread, fluorescent signals were obtained from the ears, forearms, hind legs and tail of the female and male rats.