Elevated risk of multimorbidity post-COVID-19 infection: protective effect of vaccination.

BACKGROUND: It is unclear how the coronavirus disease 2019 (Covid-19) pandemic has affected multimorbidity incidence among those with one pre-existing chronic condition, as well as how vaccination could modify this association. AIM: To examine the association of Covid-19 infection with multimorbidity incidence among people with one pre-existing chronic condition, including those with prior vaccination. DESIGN: Nested case-control study. METHODS: We conducted a territory-wide nested case-control study with incidence density sampling using Hong Kong electronic health records from public healthcare facilities and mandatory Covid-19 reports. People with one listed chronic condition (based on a list of 30) who developed multimorbidity during 1 January 2020-15 November 2022 were selected as case participants and randomly matched with up to 10 people of the same age, sex and with the same first chronic condition without having developed multimorbidity at that point. Conditional logistic regression was used to estimate adjusted odds ratios (aORs) of multimorbidity. RESULTS: In total, 127 744 case participants were matched with 1 230 636 control participants. Adjusted analysis showed that there were 28%-increased odds of multimorbidity following Covid-19 [confidence interval (CI) 22% to 36%] but only 3% (non-significant) with prior full vaccination with BNT162b2 or CoronaVac (95% CI -2% to 7%). Similar associations were observed in men, women, older people aged 65 or more, and people aged 64 or younger. CONCLUSIONS: We found a significantly elevated risk of multimorbidity following a Covid-19 episode among people with one pre-existing chronic condition. Full vaccination significantly reduced this risk increase.

[Importance and practice of standardized children's refractive development records].

The prevalence of myopia in China is increasing. The early onset and rapid progression of myopia in younger children have attracted more attention. The establishment of standardized children's refractive development records is the basis of myopic prevention and control. It would be helpful to follow the refractive status and pay more attention to the refractive development of potential myopic children, so as to reduce the prevalence of myopia. (Chin J Ophthalmol, 2021, 57: 724-726).

[It is essential to diagnose and correct children's ametropia after cycloplegic refraction].

It is essential to diagnose and assess children's ametropia after cycloplegic refraction. The use of cyclopentolate 1% eyedrops in children is safe and effective for cycloplegic refraction. An accurate prescription should be based on the actual eye position and accommodation, as well as cycloplegic refraction in children. (Chin J Ophthalmol, 2019, 55: 86-88).

[Influence of wearing long wavelength filter glasses on refractive development of children's hyperopia].

Objective: To investigate the effect of wearing long wavelength filter glasses on refractive development of children's hyperopia. Methods: Case control study. Seventeen 5-7 years' old children with high hyperopia from optometry clinic of Eye and ENT Hospital Affiliated to Fudan University were enrolled in this research. The experiment design was self-control between right and left eye, 3 children were lost during two years' period of observation, all the children's hyperopic refraction were more than +6.00 D, cycloplegic by 1% atropine. All the children were required to wear long wavelength filter glasses for 6 hours after waking up, the rest of the time with the conventional glasses. Refraction, axis and red/green match point were tested before the intervention and 3, 6, 12, 18, 24 months, after the intervention. Results: After two years' intervention, hyperopia decreased, eye axis increased, the best corrected visual acuity increased both in experimental eyes and control eyes, but there were no statistically significant difference between the two groups at each time point. All children were with normal color vision, compared to the long-wavelength light, the hyperopic eyes were more sensitive to middle-wavelength light, no significant difference was found between two groups, red/green match points were 42.802±1.216 and 42.889±1.560 respectively. After wearing long wavelength filter, red/green match point were significant decreased in the experimental group in 6 months and 12 months time points (6 months: 0.995±0. 543 vs. 0.104±0.143, t=3.04, P=0.005, 12 months: 1.096±0.392 vs. 0.17±0.248, t=2.725, P=0.008). The experiment eyes were more sensitive to long-wavelength light than the control eyes. But in later time, there was no significant difference between two groups. Conclusion: Wearing long wavelength filter glasses two years has no effect on refractive development on children with high hyperopia, but it can cause short-term chromatic adaptation, making hyperopic eyes more sensitive to the long-wavelength light. (Chin J Ophthalmol, 2017, 53: 33-38).

[The histopathological observation of rabbit corneas after small incision lenticule extraction].

OBJECTIVE: To evaluate the morphological changes during corneal wound healing after small incision lenticule extraction (SMILE). METHODS: Twenty-one New Zealand white rabbits were randomly divided into 2 groups (group A of 12 rabbits and group B of 9 rabbits) using the toss of a coin. All the right eyes were treated. Group A underwent SMILE, and group B underwent femtosecond laser-assisted in situ keratomileusis (LASIK), with the same refractive corrections of-6.00 DS/-1.00 DC. The surface regularity on the refractive corneal lenticules and flaps was evaluated by scanning electron microscopy. Light microscopy and transmission electron microscopy were applied to observe changes in the cornea on postoperative week 1, months 1 and 3. The contralateral eye of three rabbits served as control. RESULTS: All the operations were successful, and the postoperative corneal healing was uneventful in both groups. The recovery of corneas was faster in the SMILE group by slit-lamp examination. Light microscopy confirmed the mild edema of corneal stroma with a clear intrastromal crevice in the SMILE group and the adhesion of the flap and stromal bed in the LASIK group on postoperative week 1. The filling of epithelial cells at the flap margin and the irregular arrangement of collagens were demonstrated in both groups. On postoperative month 1, stromal edema was dissipated, and collagens became more regular in both groups. The intrastromal crevice in the SMILE group disappeared on postoperative month 3. Transmission electron microscopy also revealed the edema of keratocyte mitochondria within 1 month, and the keratocytes recovered to normal on month 3. The surface regularity of the front surface was better than that of the back. CONCLUSIONS: Smooth intrastromal lenticules can be safely prepared by femtosecond laser. The corneal healing in the SMILE group was better than that in the LASIK group. The intrastromal crevice in the early postoperative period after SMILE should be paid attention to clinically. (Chin J Ophthalmol, 2016, 52: 507-513).

Arg555Gln mutation of TGFBI gene in geographical-type Reis-Bücklers corneal dystrophy in a Chinese family.

OBJECTIVE: Mutations of the transforming growth factor ß-induced (TGFBI) gene were studied in a Chinese family with Reis-Bücklers corneal dystrophy (RBCD). METHODS: Six family members with RBCD and six unaffected family members were investigated. The pedigree showed a typical dominant inheritance pattern. Genomic DNA was extracted from peripheral leucocytes from all study participants. Exons 4, 12 and 14 of the TGFBI gene were analysed using polymerase chain reaction, and standard automated sequencing was performed. Corneal tissue sampled from the proband during phototherapeutic keratectomy was examined using transmission electron microscopy (TEM). RESULTS: A typical geographical pattern of fine opacities in Bowman's layer of the cornea was seen in all six patients on slit-lamp examination. An Arg555Gln (R555Q) mutation of the TGFBI gene was identified in all six patients but was absent in all unaffected family members. TEM revealed rod-shaped bodies in Bowman's layer of the cornea. CONCLUSIONS: In this Chinese family an R555Q mutation of the TGFBI gene was associated with RBCD. As the RBCD phenotype is usually associated with an R124L mutation, this novel genotype-phenotype correlation may prompt further investigation of Bowman's layer corneal dystrophy.

Covalent bonding and hole-electron Coulomb interaction U in C(60) on Be(0001) surfaces.

We have investigated the bonding nature and hole-electron Coulomb interaction U in thin C(60) films on Be(0001) surfaces using valence-band and core-level photoemission, inverse photoemission, and near-edge x-ray absorption spectroscopies. The C(60) monolayer had strong covalent bonding with the Be substrate, producing a nearly insulating film, in contrast to a metallic overlayer due to charge transfer observed on many other metallic surfaces. The effect of polarization of surrounding molecules and the image potential decreases the energy gap and U, but the bonding-antibonding contribution increases the gap at the interface. The measured U in thin solid films agrees well with a model calculation using gas-phase values. The deduced hole-electron attraction on the surface is about 0.7 eV larger than the reported hole-hole repulsion determined by Auger spectroscopy. On the basis of the surface-solid difference, the newly estimated value of U for hole-hole correlation places doped C(60) compounds nearer the metallic side of a Mott transition.

A study of GafChromic XR Type R film response with reflective-type densitometers and economical flatbed scanners.

The GafChromic XR Type R film is a relatively new product for recording high radiation dose in interventional radiological procedures. Means of measuring the film response were studied in this investigation. Two handheld reflective-type densitometers of different models were compared in the range of 0-8 Gy. They were found to be in excellent agreement. Five reflective flatbed scanners of different models were compared by a simple preliminary test. Their widely differed performances suggest the need of testing a scanner before using it for dosimetry measurement. A selected scanner was further tested for its ability to measure radiation in the range of 0-8 Gy and for the development of a scanning protocol. This experiment suggested the inclusion of a calibration pattern with known exposures and a black reference step in the scanning of a film in RGB mode. Then the red component of this image should be used for dosimetry computation. This method was compared to the use of a red acetate filter. The latter was demonstrated to be a possible alternative for measurement below 5 Gy and when there is no software ability to split an image into color components.

[Studies of the association of pathological myopia in Chinese patients with HLA alleles].

The second exons of the HLA-DQB1 genes in 55 patients with Pathological Myopia were amplified and then digested with ApaI, Bsp1286I, BsaHI, BssHII, HaeII, HaeIII, HpaII, RsaI to determinate the genotypes and the allele frequencies. Among the 16 alleles, HLA-DQB1*0201, *0301, *0303, *0401 alleles in PM patients differed significantly from that of the normal ones in the distribution of the alleles, and seemed to be the pathogenic genes (P < 0.05; AF = 0.1636, 0.1091, 0.1636, 0.1091 vs. 0.0400, 0.0300, 0.0400, 0.0200; RR = 4.2886, 3.5350, 4.2890, 5.0000); While the HLA-DQB1*0601, *0602 frequencies in PM patients were remarkably lower than that of the normal ones, which showed the property of protective genes (Pc = 0.0000, AF = 0.1182, 0.0818 vs. 0.4300, 0.3100). DQB1*05.32, *0504 and *0605 can not be detected. The association of PM with DQB1 was found for the first time in the world, which has great significance both to theoretical study and to clinical diagnosis.

Stability of a dry laser imaging system.

Laser imagers are the method of choice for creating hard copies of electronic images, such as computed tomograms and computed radiographs. New dry laser imagers use heat processing rather than wet chemical processing. This article describes tests assessing the stability and reproducibility of dry-processed laser images under normal conditions. The authors conclude that dry laser images compare favorably with wet laser images, although testing under extreme conditions is needed.

Patient doses in abdominal aortogram and aorta femoral runoff examinations.

Radiation doses to adult male patients from abdominal aortogram and aorta femoral runoff examinations in a medical center were determined with the help of a dose-area product meter. The abdominal aortogram and aorta femoral runoff examination consisted of scout radiographs, fluoroscopy (to position a catheter near the area of interest), and serial films (to record the flow of contrast media). Measurements were converted to effective doses with the help of published results from Monte Carlo simulation calculations. Data from 19 male adult patients weighing 53 to 86 kg were analyzed. The resulting total effective dose had a value of 14.0 +/- 4A mSv (mean and standard deviation). The percent contribution by fluoroscopy was 18.5 +/- 9.9%. The fluoroscopy effective dose had a stronger correlation with the dose-area product (correlation coefficient of 0.97) than with duration of exposure (correlation coefficient of 0.84). Most of the radiation exposure in the observed abdominal aortogram and aorta femoral runoff examination was attributed to radiography.

Entrance skin exposure in PA chest radiography.

To determine whether entrance skin exposure during chest radiography is related to the thickness of the patient's chest, the authors used a dose-area product meter to record ESE during posteroanterior chest examinations of adult male patients. Manual adjustment of collimation and automatic exposure control were used. Analysis of the results showed a weak correlation between radiation exposure and chest thickness. The equivalent chest thicknesses of anthropomorphic phantoms are thinner than the chest thicknesses of most adult patients. Therefore, if it is necessary to measure the entrance skin exposure to a patient, it should be measured directly or computed from the actual technique used. An examination of the distribution of recorded dose-area product shows that this parameter can be a quality control criterion for limiting the field size in manual collimation.

Measurement of skin entrance exposure with a dose-area-product meter at chest radiography.

Skin entrance exposure measurements obtained with a dose-area-product meter and thermoluminescent dosimeters were compared at posteroanterior and lateral chest radiography in 52 adult male patients. In a linear regression analysis of data collected in both views, values of 1.23 +/- 0.02 and 1.26 +/- 0.01 (r = .98 and .99) were found for the ratios of thermoluminescent-dosimeter and dose-are-product exposures, respectively. Skin entrance exposures from 16 mR (4.13 microC/kg) to 150 mR (38.7 microC/kg) in the posteroanterior view and 24 mR (6.19 microC/kg) to 475 mR (123 microC/kg) in the lateral view were found. Dose-area-product meters offer a rapid and accurate means to measure skin entrance exposure when the radiography field size is known.

[Cephradine delivery into the eye with domestic collagen shield].

The author reports that enhancement by the native made collagen-shield on the permeation of cephradine into the eye is 1.5 times and 1.3 times versus controls when the corneal epithelium is intact or defect, and is 10 times versus frequent eyedrops instillation. On the other hand, the enhancement of the collagen-shield is about the same as that of the soft contact lens impregnated with cephradine solution, but the drug concentration in aqueous humor is increased by collagen-shield 1-2 times than that by the wet soft contact lens. These results indicate that the collagen-shield can effectively increase the drug concentration in aqueous humor.

[Long-term results of radial keratotomy (RK)].

Among myopic patients performed RK with operative parameters stipulated by the authors' own computer software, 77 cases (152 eyes) were followed up over 1 year to find that 68% of the eyes with preoperative myopia of < or = -6.00DS attained visual acuity of 1.0 or better, and incision depths over 80% of the corneal thickness were conducive to long-term good effects: hence accurate determination of the corneal thickness was very important. In view of the limitations of RK, the authors suggested indications and contraindications for the procedure.

First-pass studies of acute lung injury.

Mild hydrochloric acid was introduced to a caudal lung section in each of eight dogs to induce injury. Transits of 99mTc-labeled red blood cells (RBC) and [123I]iodoantipyrine (IAP) injected intravenously were recorded by a scintillation camera. Lungs and blood samples were analyzed post-mortem. Peak-to-equilibrium ratios (P/E) of RBC time-activity curves were computed to be 3.83 +/- 0.54 for the control lung, 2.58 +/- 0.55 for the injured lung and 2.23 +/- 0.58 for the injured caudal section. For IAP, the respective results were 3.78 +/- 0.29, 2.02 +/- 0.18 and 1.77 +/- 0.17. The decrease of P/E in injured areas was attributed to reduced blood flow. Using mean transit times of the tracers, we computed extravascular lung water per unit blood volume to be 0.35 +/- 0.18 for the control lungs and an increased value of 0.68 +/- 0.24 for the injured lungs. These results displayed sensitivity to injury, but were gross underestimates relative to the corresponding values of 2.04 +/- 0.54 and 4.56 +/- 1.85 in post-mortem analyses.

Blood volume distribution in lung injury.

Mild hydrochloric acid was used to induce injury in the caudal section of one lung in each of 10 dogs. 99mTc-red blood cells were injected intravenously. Blood samples were drawn prior to sacrifice. Lung and blood samples were weighed, assayed for radioactivity and dried to constant weight. Assuming a uniform hematocrit, and hence a constant density, we computed blood volumes in terms of mass. The control lung had 4.32 +/- 0.62 g of extravascular lung water (EVLW) per g of bloodless dried weight (BLDW). Injury in the other lung was characterized by an elevated average of 7.08 +/- 0.79 g of EVLW per g of BLDW. The control lung contained 2.49 +/- 0.43 g of blood per g of BLDW and the injured lung contained a reduced amount of 1.69 +/- 0.55 g of blood per g of BLDW. In 8 subjects, injured portions retained the least blood volume per g of BLDW (a limiting value of 1.43 +/- 0.47 g per g). These results support a thesis of a reduction of blood volume in an injured area.

Distributions of perfusion and lung water.

We investigated the feasibility of using 123I-iodoantipyrine (123I-IAP) and 99mTc-labeled macroaggregated albumin (99mTc-MAA) to describe and compare the distributions of perfusion and water content in lung injuries. These radiopharmaceuticals were administered to 9 rabbits, 5 control and 4 with lung injuries. Isolated lungs were imaged by a scintillation gamma camera. The distribution of 123I-IAP outlined the entire lung mass whereas perfusion defect in the distribution of 99mTc-MAA was seen clearly in the case of severe lung injury.

Dual-isotope measurement of lung water.

Iodine-131-labeled iodo-antipyrine and 99mTc-labeled erythrocytes were used to measure water content in lungs. These radioactive tracers were injected into 11 dogs with injured lungs. Blood samples were drawn and the animals sacrificed. The lungs were removed, weighed and homogenized. Samples of blood and lung homogenate were assayed for 131I and 99mTc. Samples were also weighed before and after drying to a constant weight at 70-76 degrees C. Extravascular lung water was determined by the dual-isotope technique and again by gravimetric analysis. The average ratio of the results from the two different methods was 1.14 +/- 0.20. The two methods were also compared by regression analysis and the correlation coefficient was 0.97 +/- 0.09.

Dosimetry of iodoantipyrine.

Dosimetry of iodoantipyrine labeled with radioactive iodine was determined by measuring the biodistribution of 131I-iodoantipyrine in 41 female rabbits. Following administration of the radiopharmaceutical, subjects were killed at 0.5, 6, 12, 17, 24, 36, and 48 h. Organs and samples of tissues and body fluids were assayed. Results were corrected for physical decay. Exponential functions were employed to describe the time-concentration curves; representative value would be the biological half life of 9.96 +/- 0.55 h for blood. Cumulated activity estimates for 123I, 125I and 131I were then computed. Extrapolation to absorbed dose in humans followed the formulation of the Medical International Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine. The whole body absorbed doses are 7 mu Gray, 5 mu Gray and 29 mu Gray per MBq of 123I, 125I, and 131I administered respectively.