A clinical and ultrastructural investigation of the cornea in keratoconus

Keratoconus is a non-inflammatory corneal disease that progressively causes topographical alteration of the cornea as a result of thinning, and consequently leads to impaired vision. In this thesis, the clinical studies are showed that the incidence rate and severity of keratoconus in Asir province, Saudi Arabia is high with an early onset and more rapid progress to the severe disease stage at a young age compared to other countries. The result also showed that the disease required different contact lens designs to be available in the clinics and the selection of initial back optic zone radius for multiple contact lens designs should be based in the steepest keratometric reading in early stage, and on average keratometric reading on moderate and advanced stages. However, regardless of the stage of disease, tricurve contact lens design should be selected based on average keratometric reading. Ultrastructure investigation of the anterior surface of Bowman's layer using different microscopes revealed that the changes are not limited to the apical cone only, but extend to the periphery of the cornea especially in the advances stage of keratoconus. Also, although the topographical map is usually used in trephination, it was found that the topographical features alone failed to indicate the full extent of the progress of keratoconus towards the corneal periphery. Data from transmission electron microscopy and high-angle X-ray diffraction suggest that the structural abnormalities in the stromal fibrillar matrix might be influential underlying reasons for topographic changes in the keratoconic-like changes of SPARC-null and JKC mice.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Use of face masks and other personal preventive measures by Hajj pilgrims and their impact on health problems during the Hajj.

BACKGROUND: The Hajj is one of the world's largest pilgrimage and gathers millions of Muslims from different nationalities every year. Communicable diseases have been reported frequently, during and following the Hajj, and these have been linked to individual behavioural measures. This study aimed to measure the effect of personal preventive measures, such as face mask use, hand hygiene and others, adopted by pilgrims in reducing the acquisition of infectious diseases. METHODS: We conducted a cross-sectional study at the Hajj terminal in King Abdulaziz International Airport in Jeddah, Saudi Arabia. Pilgrims were approached in the airport lounges after the 2017 Hajj season and prior to the departure of their flights from Jeddah to their home countries. An electronic data collection tool ('Open Data Kit') was used to gather survey data in regards to health problems and preventive measures during the Hajj. RESULTS: A total of 2973 Hajj pilgrims were surveyed. In all, 38.7% reported symptoms of upper respiratory tract infections (URTIs) and 5.4% reported symptoms of travel diarrhoea. Compliance with face mask use was 50.2%. Changing a face mask every 4 h was found to be significantly associated with lower prevalence of URTIs [adjusted odds ratio 0.56 (95% confidence interval 0.34-0.92), P = 0.02]. There was no statistical difference between overall face mask use and URTI acquisition. The main sources of food, eating raw vegetables/food, frequency of hand washing or use of hand sanitizers were not found to be significantly associated with reported travellers' diarrhoea. Unlicensed barbers were used by 12% of pilgrims and 9.2% of pilgrims reported using blades that were reused by other pilgrims. CONCLUSION: Preventive measures are the most effective way to prevent infections. Pilgrims can benefit from face masks by changing them frequently. There is still limited information on the effect of the use of face mask in decreasing the risk of URTI in mass gatherings

Deletion of low molecular weight protein tyrosine phosphatase (Acp1) protects against stress-induced cardiomyopathy.

The low molecular weight protein tyrosine phosphatase (LMPTP), encoded by the ACP1 gene, is a ubiquitously expressed phosphatase whose in vivo function in the heart and in cardiac diseases remains unknown. To investigate the in vivo role of LMPTP in cardiac function, we generated mice with genetic inactivation of the Acp1 locus and studied their response to long-term pressure overload. Acp1(-/-) mice develop normally and ageing mice do not show pathology in major tissues under basal conditions. However, Acp1(-/-) mice are strikingly resistant to pressure overload hypertrophy and heart failure. Lmptp expression is high in the embryonic mouse heart, decreased in the postnatal stage, and increased in the adult mouse failing heart. We also show that LMPTP expression increases in end-stage heart failure in humans. Consistent with their protected phenotype, Acp1(-/-) mice subjected to pressure overload hypertrophy have attenuated fibrosis and decreased expression of fibrotic genes. Transcriptional profiling and analysis of molecular signalling show that the resistance of Acp1(-/-) mice to pathological cardiac stress correlates with marginal re-expression of fetal cardiac genes, increased insulin receptor beta phosphorylation, as well as PKA and ephrin receptor expression, and inactivation of the CaMKIIδ pathway. Our data show that ablation of Lmptp inhibits pathological cardiac remodelling and suggest that inhibition of LMPTP may be of therapeutic relevance for the treatment of human heart failure

Persistent COVID-19 symptoms at least one month after diagnosis: a national survey

Background Post-acute COVID-19 syndrome (PACS) is an important healthcare burden. We examined persistent symptoms in COVID-19 patients at least four weeks after the onset of infection, participants’ return to pre-COVID-19 health status and associated risk factors. Methods Cross-sectional study was conducted (December 2020 to January 2021). A validated online questionnaire was sent to randomly selected individuals aged more than 14 years from a total of 1397,386 people confirmed to have COVID-19 at least 4 weeks prior to the start of this survey. This sample was drawn from the Saudi ministry of health COVID-19 testing registry system. Results Out of the 9507 COVID-19 patients who responded to the survey, 5946 (62.5%) of them adequately completed it. 2895 patients (48.7%) were aged 35–44 years, 64.4% were males, and 91.5% were Middle Eastern or North African. 79.4% experienced unresolved symptoms for at least 4 weeks after the disease onset. 9.3% were hospitalized with 42.7% visiting healthcare facility after discharge and 14.3% requiring readmission. The rates of main reported persistent symptoms in descending order were fatigue 53.5%, muscle and body ache 38.2%, loss of smell 35.0%, joint pain 30.5%, and loss of taste 29.1%. There was moderate correlation between the number of symptoms at the onset and post-four weeks of COVID-19 infection. Female sex, pre-existing comorbidities, increased number of baseline symptoms, longer hospital-stay, and hospital readmission were predictors of delayed return to baseline health state (p < 0.05). Conclusion The symptoms of PACS are prevalent after contracting COVID-19 disease. Several risk factors could predict delayed return to baseline health state

Assessment of knowledge, attitude and practice of diabetic people in Najran, Kingdom of Saudi Arabia

Background: This cross-sectional hospital based study aimed at determining the level of knowledge, attitude and practice of diabetes among local people of Najran, Saudi Arabia.Methods: We aimed to investigate the levels of knowledge, attitude and practice among diabetic people in Najran area.Results: 10% of the participants scored >7, 28% scored >5 and 62% scored 5 and less in Knowledge questionnaire. None [0.00%] of the participants scored 7 or more out of the attitude questionnaire. 100% of the participants scored 5 and less out of 12. 100% of the participants scored >6 and 0% scored 12 or more in the practice questionnaire.Conclusions: Our study revealed that the level of knowledge, attitude and practice of diabetes in the area of Najran is very poor. We suggest that a structured educational program to be adopted by the health authorities in Saudi Arabia

Viral shedding and antibody response in 37 patients with MERS-coronavirus infection

Background. The Middle East respiratory syndrome (MERS) coronavirus causes isolated cases and outbreaks of severe respiratory disease. Essential features of the natural history of disease are poorly understood. Methods. We studied 37 adult patients infected with MERS coronavirus for viral load in the lower and upper respiratory tracts (LRT and URT, respectively), blood, stool, and urine. Antibodies and serum neutralizing activities were determined over the course of disease. Results. One hundred ninety-nine LRT samples collected during the 3 weeks following diagnosis yielded virus RNA in 93% of tests. Average (maximum) viral loads were 5 × 106 (6 × 1010) copies/mL. Viral loads (positive detection frequencies) in 84 URT samples were 1.9 × 104 copies/mL (47.6%). Thirty-three percent of all 108 serum samples tested yielded viral RNA. Only 14.6% of stool and 2.4% of urine samples yielded viral RNA. All seroconversions occurred during the first 2 weeks after diagnosis, which corresponds to the second and third week after symptom onset. Immunoglobulin M detection provided no advantage in sensitivity over immunoglobulin G (IgG) detection. All surviving patients, but only slightly more than half of all fatal cases, produced IgG and neutralizing antibodies. The levels of IgG and neutralizing antibodies were weakly and inversely correlated with LRT viral loads. Presence of antibodies did not lead to the elimination of virus from LRT. Conclusions. The timing and intensity of respiratory viral shedding in patients with MERS closely matches that of those with severe acute respiratory syndrome. Blood viral RNA does not seem to be infectious. Extrapulmonary loci of virus replication seem possible. Neutralizing antibodies do not suffice to clear the infection

Taguchi L25 (54) approach for methylene blue removal by polyethylene terephthalate nanofiber‐multi‐walled carbon nanotube composite

A membrane composed of polyethylene terephthalate nanofiber and multi‐walled carbon nanotubes (PET NF‐MWCNTs) composite is used to adsorb methylene blue (MB) dye from an aqueous solution. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X‐ ray diffraction techniques are employed to study the surface properties of the adsorbent. Several parameters affecting dye adsorption (pH, MB dye initial concentration, PET NF‐MWCNTs dose, and contact time) are optimized for optimal removal efficiency (R, %) by using the Taguchi L25 (54) Orthogonal Array approach. According to the ANOVA results, pH has the highest contributing percentage at 71.01%, suggesting it has the most significant impact on removal efficiency. The adsorbent dose is the second most affected (12.08%), followed by the MB dye initial concentration of 5.91%, and the least affected is the contact time (1.81%). In addition, experimental findings confirm that the Langmuir isotherm is well‐fitted, suggesting a monolayer capping of MB dye on the PET‐NF‐MWCNT surface with a maximum adsorption capacity of 7.047 mg g−1. Also, the kinetic results are well‐suited to the pseudo‐second‐order model. There is a good agreement between the calculated (qe) and experimental values for the pseudo‐second‐order kinetic model

Saudi-KAU Coupled Global Climate Model: Description and Performance

n/