Insights into hippocampal perfusion using high-resolution, multi-modal 7T MRI.

We present a comprehensive study on the non-invasive measurement of hippocampal perfusion. Using high-resolution 7 tesla arterial spin labeling (ASL) data, we generated robust perfusion maps and observed significant variations in perfusion among hippocampal subfields, with CA1 exhibiting the lowest perfusion levels. Notably, these perfusion differences were robust and already detectable with 50 perfusion-weighted images per subject, acquired in 5 min. To understand the underlying factors, we examined the influence of image quality metrics, various tissue microstructure and morphometric properties, macrovasculature, and cytoarchitecture. We observed higher perfusion in regions located closer to arteries, demonstrating the influence of vascular proximity on hippocampal perfusion. Moreover, ex vivo cytoarchitectonic features based on neuronal density differences appeared to correlate stronger with hippocampal perfusion than morphometric measures like gray matter thickness. These findings emphasize the interplay between microvasculature, macrovasculature, and metabolic demand in shaping hippocampal perfusion. Our study expands the current understanding of hippocampal physiology and its relevance to neurological disorders. By providing in vivo evidence of perfusion differences between hippocampal subfields, our findings have implications for diagnosis and potential therapeutic interventions. In conclusion, our study provides a valuable resource for extensively characterizing hippocampal perfusion.

Prospective single-center study on the reliability of ipsilateral cerebral oximetry using near-infrared spectroscopy as a predictor for selective shunting during carotid endarterectomy.

OBJECTIVE: Many techniques are available for the intraoperative assessment of brain perfusion during carotid endarterectomy, such as carotid stump pressure, near-infrared spectroscopy, somatosensory evoked potentials, transcranial Doppler, electroencephalography, and clinical assessment. The decision for selective carotid shunt insertion is dependent on clinical deterioration or the detection of cerebral hypoperfusion after cross-clamping of the internal carotid artery. Monitoring cerebral oximetry using near-infrared spectroscopy is a noninvasive technique for cerebral oxygen saturation measurement, reflecting changes in cerebral blood flow during carotid endarterectomy. The aim of this study was to evaluate the reliability of near-infrared spectroscopy as a predictor of selective shunting during carotid endarterectomy. METHODS: In total, 47 conventional carotid endarterectomy surgeries were performed at our hospital between March 2016 and December 2021. All surgeries were performed under a regional cervical block supplemented with local infiltration anesthesia. All patients were monitored by cerebral oximetry using bilateral near-infrared spectroscopy probes and clinical assessment through communication with the patient (numerical, visual, and verbal) to indicate a selective shunt. Near-infrared spectroscopy values were recorded before and after internal carotid cross-clamping and after declamping. Any decrease in ipsilateral cerebral oximetry-near-infrared spectroscopy values equal to or more than 20% from the pre-clamping baseline reading associated with deterioration in neurological status (hemiparesis, aphasia, or deterioration in level of consciousness) after internal carotid artery cross-clamping was considered an indication for intraluminal carotid shunting. RESULTS: After internal carotid artery cross-clamping, 5 of 47 patients (10.6%) developed a significant drop in cerebral oxygen saturation associated with obvious clinical assessment deterioration in verbal communication and weakness in contralateral arm power. A Pruitt-Inahara carotid shunt was subsequently inserted, and 42 patients remained stable throughout surgery. The average decline in ipsilateral near-infrared spectroscopy values was 23.8% in patients with clinical deterioration. The average decline was 8.6% in patients who remained stable. CONCLUSIONS: Monitoring ipsilateral cerebral oximetry using near-infrared spectroscopy is an easy and reliable method for indicating selective shunting during carotid endarterectomy. A 20% decrease in ipsilateral brain tissue oximetry after internal carotid artery cross-clamping provides a reliable cut-off value for selective intraluminal carotid shunting during carotid endarterectomy.

Utility of muscle ultrasound in nutritional assessment of children with nephrotic syndrome.

BACKGROUND: Nutritional status assessment in children with nephrotic syndrome (NS) is critical for identifying patients who are at risk of protein-energy wasting (PEW) and for determining their nutritional needs and monitoring nutritional intervention outcomes. METHODS: In a case-control study, we enrolled 40 children (age range: 2-16 years) with NS and 40 apparently healthy children (age and sex-matched) as a control group. Anthropometric data, as well as demographic, clinical, and laboratory data, were collected. A dietary intake assessment using a 3-day food intake record was done, and the quadriceps rectus femoris thickness (QRFT) and quadriceps vastus intermedius thickness (QVIT) were assessed using B-mode ultrasound and compared between both groups. RESULTS: Children with NS had lower QRFT and QVIT measurements than control groups (p < 0.001). Inadequacy in protein intake occurred in 62.5% and 27.5% of the NS and control groups, respectively (p = 0.002). The thickness of the rectus and vastus muscles by ultrasound was significantly associated with the percentage of protein intake (p < 0.001). The ROC curve revealed that the best cutoff value of QRFT for the prediction of the patient at risk of malnutrition was ≤ 1.195 with an area under curve of 0.907, with p < 0.001. CONCLUSION: In children with NS, skeletal muscle ultrasound is a simple and easy-to-use bedside technique for the identification of patients at risk of malnutrition. A higher resolution version of the Graphical abstract is available as Supplementary information.

Molecular characterization and genotyping of hepatitis C virus from Sudanese end-stage renal disease patients on haemodialysis.

BACKGROUND: Hepatitis C virus (HCV) is a global public health problem, with ~ 11 million people in Africa infected. There is incomplete information on HCV in Sudan, particularly in haemodialysis patients, who have a higher prevalence compared to the general population. Thus, our objectives were to genotype and molecularly characterize HCV isolated from end-stage renal disease haemodialysis patients. METHODS: A total of 541 patients were recruited from eight haemodialysis centres in Khartoum and screened for anti-HCV. Viral loads were determined using in-house real-time PCR in seropositive patients. HCV was genotyped and subtyped using sequencing of amplicons of 5' untranslated (UTR) and non-structural protein 5B (NS5B) regions, followed by phylogenetic analysis of corresponding sequences. RESULTS: The HCV seroprevalence in the study was 17% (93/541), with HCV RNA-positive viremic rate of 7% (40/541). A low HCV load, with a mean of 2.85 × 104 IU/ml and a range of 2.95 × 103 to 4.78 × 106 IU/ml, was detected. Phylogenetic analyses showed the presence of genotypes 1, 3, 4, and 5 with subtypes 1a, 1b, 1 g, 3a, 4a, 4 l, 4 m, 4 s, and 4t. Sequences of HCV from the same haemodialysis units, clustered in similar genotypes and subtypes intimating nosocomial infection. CONCLUSION: HCV infection is highly prevalent in haemodialysis patients from Sudan, with phylogenetic analysis intimating nosocomial infection. HCV genotyping is useful to locate potential transmission chains and to enable individualized treatment using highly effective direct-acting antivirals (DAAs).

Geoenvironmental approach to investigate surface and groundwater pollution-related problems in water-sensitive regions.

The desert environment is a clean, dynamic system due to its remoteness from human interventions. Yet, sometimes it is approached by anthropogenic activities that change its balanced ecosystem. The present study states that the non-planned construction of wastewater plants has affected the environment and led to water resource deterioration. The presented approach is based on the integration of hydrogeologic data together with remote sensing and GIS applications as well as statistical, chemical, biochemical, and bacteriological analyses of water samples. The groundwater showed high salinity values (up to 13,236 mg/l) where it is extracted from two coastal aquifers; the Middle Miocene aquifer represents the main one, while the Pleistocene aquifer is of limited use. The obtained results reveal the existence of pollution indicators in both stored rainwater and groundwater where the colony bacteria, NO3, chemical and biological oxygen demands, and total organic carbon exceed the permissible limits. The satellite images acquired between 2003 and 2021 demonstrated a land use change through the construction of a wastewater plant with two forests that led to the spreading of the partially treated water over the Marmarica Plateau. The photogeological lineaments are extracted where the plateau is affected by many faults (NE-SW, NW-SE, and E-W) that facilitate surface-groundwater interaction. The results indicate that the studied groundwater becomes vulnerable to the existing pollution sources, with the possibility of being affected by climate change and saltwater intrusion. Therefore, this integrated approach is presented to assess the current environmental problems and suggests a strategy to mitigate the pollution hazards.

Lassa fever amidst the COVID-19 pandemic in Africa: A rising concern, efforts, challenges, and future recommendations.

Lassa fever, caused by the Lassa virus of the Arenaviruses family, is a re-emerging public health concern that has led to 300,000 infections and 5000 deaths annually in Africa. Highly prevalent in Sierra Leone, Liberia, Guinea, Nigeria, Côte d'lvoire, Ghana, Togo, and Benin, patients infected with the virus can manifest with cough, sore throat, headache, nausea, and vomiting among other symptoms. Coexisting with the coronavirus disease 2019 (COVID-19) pandemic and its impacts, cases of Lassa fever in the African population have been reported to decrease due to hesitancy in visiting clinics that leads to unreported cases-all contributing to a silent outbreak in West Africa. Thus, to overcome current burdens, gaps, and challenges caused by Lassa fever amidst COVID-19 in Africa, various recommendations for efficient control of transmission, measures for disease containment, and strategies to correct misperceptions were made.

Fexofenadine and Rosuvastatin Pharmacokinetics in Mice with Targeted Disruption of Organic Anion Transporting Polypeptide 2B1.

Organic anion transporting polypeptide 2B1 (OATP2B1) is a widely expressed membrane transporter with diverse substrate specificity. In vitro and clinical studies suggest a role for intestinal OATP2B1 in the oral absorption of medications. Moreover, OATP2B1 is highly expressed in hepatocytes where it is thought to promote liver drug clearance. However, until now, a shortcoming of studies implicating OATP2B1 in drug disposition has been a lack of in vivo models. Here, we report the development of a knockout (KO) mouse model with targeted, global disruption of the Slco2b1 gene to examine the disposition of two confirmed mOATP2B1 substrates, namely, fexofenadine and rosuvastatin. The plasma pharmacokinetics of intravenously administered fexofenadine was not different between KO and wild-type (WT) mice. However, after oral fexofenadine administration, KO mice had 70% and 41% lower maximal plasma concentration (C max) and area under the plasma concentration-time curve (AUC0-last) than WT mice, respectively. In WT mice, coadministration of fexofenadine with grapefruit juice (GFJ) or apple juice (AJ) was associated with reduced C max by 80% and 88%, respectively, while the AUC0-last values were lower by 35% and 70%, respectively. In KO mice, AJ coadministration reduced oral fexofenadine C max and AUC0-last values by 67% and 59%, respectively, while GFJ had no effects. Intravenous and oral rosuvastatin pharmacokinetics were similar among WT and KO mice. We conclude that intestinal OATP2B1 is a determinant of oral fexofenadine absorption, as well as a target for fruit juice interactions. OATP2B1 does not significantly influence rosuvastatin disposition in mice. SIGNIFICANCE STATEMENT: A novel mouse model with targeted disruption of the Slco2b1 gene revealed that OATP2B1 is a determinant of oral absorption but not systemic disposition of fexofenadine, as well as a target of fruit juice interactions. Rosuvastatin oral and intravenous pharmacokinetics were not dependent on OATP2B1. These findings support the utility of the Slco2b1 KO mouse model for defining mechanisms of drug disposition at the intersection of in vitro and clinical pharmacology.

Application of a Revised Tissue Saving Protocol for Combined Topography-Guided Photorefractive Keratectomy and Cross-Linking in a Cohort Having Pellucid Marginal Degeneration.

Purpose: To evaluate the efficiency, safety, and stability of a revised tissue-saving treatment protocol in a cohort having pellucid marginal degeneration (PMD). Methods: A retrospective cohort study was conducted on patients with PMD and no previous treatments. A revised protocol of topo-guided photorefractive keratectomy to be followed by customized phototherapeutic keratectomy and then corneal crosslinking was evaluated by comparing the pre and postoperative outcomes regarding visual (subjective refraction) and topographic (using data from Sirius CSO topography software) outcomes. Results: There were both statistically significant and clinically relevant improvements in the postoperative parameters, where each of the unaided and corrected visual acuity, spherical equivalent, refractive cylinder, K readings, topographic cylinder, inferior minus superior difference at the 2- and 4- mm diameters, coma aberration, and higher order aberrations were significantly better postoperatively (all p values were less than 0.01, except for maximum k readings where the p-value was 0.017). The safety and efficacy indices for the surgical procedure were remarkably high (1.53 ± 0.70 and 0.90 ± 0.32, respectively). Conclusion: Our proposed tissue-saving protocol (which showed satisfactory results in keratoconus cases according to a previously published article by our research team) has proven its successful outcomes (both topographically and visually) in cases of PMD, which is a rare ectatic entity with guarded prognosis using the available conventional ectasia treatment modalities.

Comparing the Postoperative Outcomes of Intrastromal Corneal Ring Segments in Three Different Topographic Patterns of Eccentric Keratoconus.

PURPOSE: To compare the postoperative outcomes following implantation of KERATACx ring segments (Imperial Medical Technologies Europe GmbH) in patients having eccentric keratoconus with three different topographic patterns. METHODS: This retrospective cohort study was conducted at Maadi Eye Subspeciality Center, Cairo, Egypt. The study included patients with keratoconus who had implantation of KERATACx ring segments. Three groups were segregated based on topographic keratoconus patterns using the Sirius CSO Topographer (CSO Italia): type I ectasia where the cone coincides with the corneal flat axis, type II ectasia in which the cone coincides with neither the steep nor the flat axis and lies between the two axes, and type II ectasia for cones coinciding with the corneal steep axis. The visual and topographic outcomes were compared preoperatively and postoperatively for the three enrolled groups. RESULTS: This study enrolled 92 eyes of 92 patients and had a mean ± standard deviation follow-up of 16.9 ± 9.2 months. The patients' medical records revealed that night vision complaints and halos around the light were experienced the most by the type III ectasia group (31.25%). For the type III ectasia group, four topographic indices and one visual parameter did not show statistically significant differences between the preoperative and postoperative data (inferior-superior difference at 2- and 4-mm diameter, coma aberration, higher order aberrations, and uncorrected distance visual acuity), contrary to the type I and II ectasia groups, which showed significant improvements in all evaluated parameters. CONCLUSIONS: The type III morphological pattern of ectasia is the least likely to benefit from KERATACx ring segments implantation. [J Refract Surg. 2024;40(9):e625-e634.].

Extensor pollicis longus tendon penetration by a screw post-distal radius fracture plating in a young woman: A case report.

INTRODUCTION: Due to its ability to provide stable fixation and permit early mobilization, volar plating has become the recommended technique for the surgical stabilization of distal radius fractures. The extensor pollicis longus (EPL) tendon may be injured or ruptured as a result of undetected screw penetration or drill plunging. During surgery, it is critical to detect any potential screw penetration so that it can be corrected. CASE PRESENTATION: A 32-year-old woman presented six weeks post-distal radius plating with an inability to extend her left thumb. Clinical examination revealed loss of extension at the interphalangeal joint, stiff wrist, tender point over the dorsal aspect of the wrist, and an intact sensory nerve function. DISCUSSION: Dynamic ultrasound and magnetic resonance imaging (MRI) both revealed no evidence of tendon rupture or EPL tendon movement. X-rays revealed the distal epiphyseal screws penetrating the far cortex. Intraoperatively, the EPL tendon was found to be impinged by a screw. The tendon was released, tenolysis was performed, and the distal screws were shortened. CONCLUSION: In order to assess screw penetration into the far cortex, volar plating for distal radius fractures should be performed using intraoperative imaging views such as lateral, 45-degree supination, 45-degree pronation, dorsal tangential, and skyline views. Timely interventions after distal radius fracture fixation preserve tendon function, and early detection of tendon compromise is essential to preventing additional damage.

Pigmented dentinogenic ghost cell tumor: a unique case report and a review of the literature.

Dentinogenic ghost cell tumors are rare tumors, and few cases of them were reported in the literature. The presence of pigment in odontogenic lesions is a rare unexplained histological finding. In this report, we describe a unique case of a 7-year-old girl that was referred to the Department of Oral and Maxillofacial Surgery complaining of a left mandibular swelling. Clinical examination revealed a huge, ulcerated mass. Both incisional and excisional biopsies revealed a benign infiltrative odontogenic tumor with admixed ameloblast-like cells and pigmented ghost cells, consistent with a pigmented dentinogenic ghost cell tumor. To the best of our knowledge, this is the youngest case of intraosseous dentinogenic ghost cell tumor reported in the English literature and the second report of a pigmented variant. This rare variant should be included in the differential of pigmented odontogenic lesions to avoid misinterpretation, especially in small biopsies.

Subscapularis pyomyositis, a rare cause of shoulder pain, in a patient without apparent risk factors: A case report.

INTRODUCTION: Pyomyositis, previously tropical, now seen more in temperate zones, particularly in those with HIV, cancer, or diabetes. Even healthy individuals, like athletes, can get it post-exercise or minor injuries. Our patient, in a desert-like area, adds an interesting aspect. Diagnosing is challenging due to deep tissue occurrence and subtle symptoms, leading to delayed detection and higher risks of morbidity. PRESENTATION OF CASE: A 45-year-old female patient presented with acute left shoulder pain and functional impairment, exacerbated by movement. Clinical examination revealed tenderness upon deep palpation in the left upper posterior thoracic region and restricted range of motion of the affected shoulder. DISCUSSION: Initial assessments at medical facilities suggested musculoskeletal strain and lower cervical disc prolapse despite normal X-ray results. MRI scans confirmed a developing abscess in the left subscapularis muscle, with intraoperative findings revealing extensive purulent fluid and necrotic tissue. Four surgeries drained the abscess and treated fat necrosis, with tailored antibiotics administered. Subsequent arthroscopy showed fibrous tissue, swelling, and inflammation. At the 3-month check-up, she had fully recovered, experiencing no pain or complications, and had almost regained full range of motion. CONCLUSION: Shoulder pyomyositis presents diagnostic challenges, causing delayed treatment. This case highlights the importance of considering pyomyositis in severe shoulder pain cases, even without typical risk factors or inconclusive X-rays. Timely recognition, surgical drainage, tailored antibiotics, and physical therapy are crucial. An interdisciplinary approach with orthopaedic surgery, infectious disease specialists, radiology, and physical therapy is vital for comprehensive management, improving outcomes, and reducing complications.

Comparative efficacy of proximal femoral nail vs dynamic condylar screw in treating unstable intertrochanteric fractures.

BACKGROUND: Among the most frequent hip fractures are trochanteric fractures, which usually occur from low-energy trauma like minor falls, especially in older people with osteoporotic bones. AIM: To evaluate the treatment efficacy of dynamic condylar screws (DCS) and proximal femoral nails (PFN) for unstable intertrochanteric fractures. METHODS: To find pertinent randomized controlled trials and retrospective observational studies comparing PFN with DCS for the management of unstable femoral intertrochanteric fractures, a thorough search was carried out. For research studies published between January 1996 and April 2024, PubMed, EMBASE, Scopus, Web of Science, Cochrane Library, and Google Scholar were all searched. The complete texts of the papers were retrieved, vetted, and independently examined by two investigators. Disputes were settled by consensus, and any disagreements that persisted were arbitrated by a third author. RESULTS: This study included six articles, comprising a total of 173 patients. Compared to the DCS, the PFN had a shorter operation time [mean difference (MD): -41.7 min, 95% confidence interval (95%CI): -63.04 to -20.35, P = 0.0001], higher success rates with closed reduction techniques [risk ratio (RR): 34.05, 95%CI: 11.12-104.31, P < 0.00001], and required less intraoperative blood transfusion (MD: -1.4 units, 95%CI: -1.80 to -1.00, P < 0.00001). Additionally, the PFN showed shorter fracture union time (MD: -6.92 wk, 95%CI: -10.27 to -3.57, P < 0.0001) and a lower incidence of reoperation (RR: 0.37, 95%CI: 0.17-0.82, P = 0.01). However, there was no discernible variation regarding hospital stay, implant-related complications, and infections. CONCLUSION: Compared to DCS, PFN offers shorter operative times, reduces the blood transfusions requirements, achieves higher closed reduction success, enables faster fracture healing, and lowers reoperation incidence.

Implementing an Internal Audit: Evaluating Hand Scrub Compliance in a Tertiary Care Hospital.

Background Aseptic protocol adherence and sterilization are the most important factors in a patient's satisfactory recovery after surgery. The standard hand scrubbing procedure helps control infection and keeps the surgical site clean by adhering to aseptic principles. Methods Thirty-six young residents and house officers participated in this prospective audit after ethical clearance was obtained. The World Health Organization (WHO) standard criteria were adhered to both before and after the intervention. Participants were observed in the surgical operation theatre (OT) without prior notice to ensure hand hygiene compliance before surgical procedures. The intervention included a video presentation as well as a live demonstration. Results Only 64.41% (n=23) of residents and house officers followed the recommended standard hand hygiene procedures before the intervention. This percentage rose to 93.92% (n=33) following the intervention, suggesting a noteworthy improvement. Conclusion Significant changes in the acceptance rates for the essential requirements of hand hygiene were observed after the evaluation in the second cycle. Adhering to WHO guidelines for procedures will help reduce the risk of infections and promote awareness of asepsis in practice.

Role of AGC kinases in plant growth and stress responses.

AGC kinases are important regulators of cell growth, metabolism, division, and survival in mammalian systems. Mutation or deregulation of members of this family of protein kinases contribute to the pathogenesis of many human diseases, including cancer and diabetes. Although AGC kinases are conserved in the plant kingdom, little is known about their molecular functions and targets. Some of the best-studied plant AGC kinases mediate auxin signaling and are thereby involved in the regulation of growth and morphogenesis. Furthermore, certain members are regulated by lipid-derived signals via the 3-phosphoinositide-dependent kinase 1 (PDK1) and the kinase target of rapamycin (TOR), similar to its animal counterparts. In this review, we discuss recent findings on plant AGC kinases that unravel important roles in the regulation of plant growth, immunity and cell death, and connections to stress-induced mitogen-activated protein kinase signaling cascades.

Novel Technique to Improve the Efficacy of Corneal Cross Linking in Cases of Post LASIK Ectasia.

Purpose: The aim of the present study was to validate the use of a novel technique that can improve the efficacy of corneal cross-linking (CXL) in cases with post LASIK ectasia. Methods: This is a retrospective, comparative study that was conducted on patients who sought medical advice at Ain Shams University Hospitals and Maadi Eye Subspeciality Center, Cairo, Egypt. It included two groups of patients with post LASIK ectasia. Group 1 included patients who performed our proposed protocol (topo-guided PRK, followed by customized phototherapeutic keratectomy "PTK" to transmit the laser treatment to the corneal stroma, then CXL). For group 2, accelerated CXL was performed. Subjective refraction and relevant topographic/tomographic parameters (Sirius topographer) compared between the two groups. Recorded follow-ups included the 2 to 3-month follow-up visit and the last visit (mean ± SD of 17.2 months ± 10.2). Results: Patients of group 1 (22 eyes of 22 patients) experienced significant improvements in most of the evaluated parameters at the 2- to 3-month follow-up visit and showed stability of the ectatic condition at the last follow-up visit, whereas patients of group 2 (10 eyes of 10 patients) showed stability of their ectatic condition at the 2- to 3-month follow-up visit, and one patient developed ectasia progression at the last follow-up visit. Conclusion: The present study validates the use of our novel protocol in cases having post LASIK ectasia with proven efficacy, safety, and stability, providing regularization for the corneal surface while simultaneously avoiding the unnecessary loss of cross-linking effect within the LASIK flap that no longer shares in the corneal biomechanical strength.

Introducing a Revised Tissue Saving Protocol for Combined Topography-Guided Photorefractive Keratectomy and Cross-Linking in Keratoconic Corneas.

PURPOSE: The aim of this study was to introduce a revised tissue-saving technique for combined topography-guided photorefractive keratectomy (PRK) and cross-linking for keratoconus (KC) treatment and to evaluate its efficacy, safety, and stability. METHODS: This retrospective, noncontrolled study was performed at Maadi Eye Subspecialty Center and Eye Care Center, Cairo, Egypt. The technique was performed on virgin keratoconic corneas with 3 different morphological patterns of ectasia. It involves performing topography-guided PRK before epithelial removal, followed by customized phototherapeutic keratectomy (PTK) that is tailored to each cornea after studying the treatment profile on the laser treatment screen. The electronic medical records were explored for preoperative and postoperative data, including subjective refraction and topographic data (using Sirius topographer). RESULTS: The study was conducted on 123 eyes of 93 patients with a mean age of 27.98 years ±6.06. The follow-up ranged from 6 to 36 months (mean ± SD of 16.2 months ±10.4). The results showed statistically nonsignificant differences among the 3 ectasia subgroups in treatment spherical equivalent, treatment maximum depth, thickness of removed epithelium, and thinnest residual stromal bed. There were statistically significant differences in almost all values between the preoperative and postoperative data, with significant postoperative patients' improvement ( P value <0.001). The subgroups' results were almost the same as the whole cohort's results. The safety and efficacy indices of the performed procedure showed remarkably high values (1.48 ± 0.21 and 0.87 ± 0.40, respectively). CONCLUSIONS: This revised protocol for KC management maximally preserves stromal tissue with proven efficacy, safety, and stability.

Comparison Between Pulsed and Continuous Accelerated Corneal Cross-Linking Protocols.

Purpose: To compare between two accelerated corneal cross-linking (A-CXL) protocols in the management of keratoconus (KC) as regard to the extent of corneal treatment. Methods: This retrospective, comparative study included patients having mild to moderate, progressive KC. The study population was divided into two groups; group 1 enrolled 103 eyes of 62 patients who received pulsed light A-CXL (pl-CXL) at a power of 30 mW/cm2 with an irradiation time of 4 minutes, while group 2 comprised 87 eyes of 51 patients who received continuous light A-CXL (cl-CXL) at a power of 12 mW/cm2 with an irradiation time of 10 minutes. Recordings of the central and peripheral demarcation line depths (DD), and the maximum (DDmax) and minimum (DDmin) DD, using anterior segment optical coherence tomography, were compared between the two studied groups one month after the treatment protocol. Treatment stability was also evaluated pre and postoperatively (one year following surgery) by comparing the refractive and keratometric outcomes in both groups. Results: The differences between the preoperative corneal thickness (minimum and central) and the epithelial thickness measurements between both groups were not statistically significant. Although group 1 had slightly larger central DD (223.4 ± 62.3 um), DDmax (240.4 ± 61.8 um), and DDmin (201 ± 54 um) than those of group 2 (221.8 ± 37 um, 229.1 ± 38.4 um, and 212 ± 37.2 um, respectively), the differences between both groups' measurements were not statistically significant. Also, the two groups showed statistically insignificant differences regarding the subjective refraction and the average and maximum keratometry pre and postoperatively, denoting visual, refractive, and keratometric stability in both groups. Conclusion: Longer duration cl-CXL seems to be as effective as pl-CXL regarding both postoperative stability and the extent of corneal tissue penetration by the ultraviolet treatment.

Novel insights into hippocampal perfusion using high-resolution, multi-modal 7T MRI.

We present a comprehensive study on the non-invasive measurement of hippocampal perfusion. Using high-resolution 7 Tesla arterial spin labelling data, we generated robust perfusion maps and observed significant variations in perfusion among hippocampal subfields, with CA1 exhibiting the lowest perfusion levels. Notably, these perfusion differences were robust and detectable even within five minutes and just fifty perfusion-weighted images per subject. To understand the underlying factors, we examined the influence of image quality metrics, various tissue microstructure and morphometry properties, macrovasculature and cytoarchitecture. We observed higher perfusion in regions located closer to arteries, demonstrating the influence of vascular proximity on hippocampal perfusion. Moreover, ex vivo cytoarchitectonic features based on neuronal density differences appeared to correlate stronger with hippocampal perfusion than morphometric measures like gray matter thickness. These findings emphasize the interplay between microvasculature, macrovasculature, and metabolic demand in shaping hippocampal perfusion. Our study expands the current understanding of hippocampal physiology and its relevance to neurological disorders. By providing in vivo evidence of perfusion differences between hippocampal subfields, our findings have implications for diagnosis and potential therapeutic interventions. In conclusion, our study provides a valuable resource for extensively characterising hippocampal perfusion.