Biomechanical and morphological changes of rabbit corneas under collagenase type II and negative pressure: three months follow-up observation

Abstract Background To investigate biomechanical and morphological changes of rabbit cornea ectasia induced by collagenase type II and negative pressure during 3 months after treatment. Method Eighteen New Zealand white rabbits were randomly and evenly arranged into three groups. The left corneas were continuously treated by negative pressure suction (NP group) with 500 mmHg for 30 min once two days, three times in total. The central area of left corneas were soaked in the collagenase type II (CII group) solution (200 μL of 3 mg/ml) for 30 min. The left corneas (CP group) were disposed as CII group firstly, then applied negative pressure suction as NP group for once after 5 days. All right corneas were treated as control eyes. Corneal morphology parameters and Ocular Response Analyzer (ORA) output parameters were collected in vivo once a week for three weeks after treatment and before execution. Histology and biomechanics were tested in vitro at the third month after treatment. Paired t-test and repeated measures analysis were used to determine if there were differences in biomechanical and morphological related parameters across time. Results In NP group, corneal thickness and diopter changed to some extent after treatment immediately, and the elastic modulus increased and relaxation degree slowed after 3 months. In CII group, corneal diopter increased, corneal central thickness (CCT) and corneal hysteresis (CH) decreased at the second week after treatment, which showed the characters of ectatic corneas. Then the degree of ectasia decreased with time. No regular changes was found on experimental corneas in CP group. Conclusions Collagenase type II results in ectatic corneas around two weeks after treatment, but the degree of ectasia decreased with time, and there was no significant difference compared with the controls after 3 months. After negative pressure suction, corneal morphology changed in a short period, and elastic modulus increased and relaxation time increased after a three months recovery, indicating that the negative pressure suction do have a certain effect on corneas.

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Biomechanical and morphological changes of rabbit corneas under collagenase type II and negative pressure: three months follow-up observation

10.21203/rs.2.22389/v2 ◽

2020 ◽

Author(s):

Xinyan Chen ◽

Xiao Qin ◽

Mengyao Yu ◽

Haixia Zhang ◽

Lin Li

Keyword(s):

Elastic Modulus ◽

Negative Pressure ◽

Morphological Changes ◽

Corneal Thickness ◽

Central Zone ◽

Large Individual ◽

Type Ii ◽

The Third ◽

Short Period

Abstract Background To investigate biomechanical and morphological changes of rabbit cornea ectasia induced by collagenase type II and negative pressure during 3 months after treatment. Method Eighteen New Zealand white rabbits were randomly and evenly arranged into three groups. In group NP, the corneas were continuously attracted by negative pressure with 500 mmHg for 30 min, treated by every other day, three times in total. In group CII, the corneal central zone was soaked in the collagenase type II solution (200 μL of 3 mg/ml) for 30 min. In group CP, the corneas were disposed as group CII firstly, then applied negative pressure as group NP for once after 5 days. All right eyes were treated as control eyes. Corneal morphology and biomechanical related parameters were observed in vivo once a week for three weeks after treatment and before execution. Histology and biomechanics were tested in vitro at the third month after treatment. Results Corneal diopter and corneal central thickness (CCT) changed to some extent after treatment immediately as a result of negative pressure in group NP. The corneas in Group NP had smaller elastic modulus and slower relaxation degree compared with the control one 3 months after treatment. In Group CII, corneal diopter increased, CCT and CH decreased at the second week after treatment, which showed the characters of ectatic corneas. At the third month after treatment, elastic modulus (EL) of the experimental eyes decreased slightly compared with the control eyes. Due to the large individual differences, there were no regular changes on experimental corneas in Group CP. Conclusions Cornea socked with collagenase type II showed the obvious characteristics of ectatic cornea at the second week after treatment, but the characteristics disappeared gradually. Negative pressure can result in the change of corneal thickness and diopter in a short period of time, and the degree of swelling and duration are far less than Group CII, but the changes of biomechanical parameters are more obviously than Group CII.

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Biomechanical and morphological changes of rabbit corneas under collagenase type II and negative pressure: three months follow-up observation

10.21203/rs.2.22389/v1 ◽

2020 ◽

Author(s):

Xinyan Chen ◽

Xiao Qin ◽

Mengyao Yu ◽

Haixia Zhang ◽

Lin Li

Keyword(s):

Elastic Modulus ◽

Negative Pressure ◽

Morphological Changes ◽

Corneal Thickness ◽

Central Zone ◽

Large Individual ◽

Type Ii ◽

The Third ◽

Short Period

Abstract Background: To investigate biomechanical and morphological changes of rabbit cornea ectasia induced by collagenase type II and negative pressure during 3 months after treatment.Method: Eighteen New Zealand white rabbits were randomly and evenly arranged into three groups. In group NP, the corneas were continuously attracted by negative pressure with 500 mmHg for 30 min, treated by every other day, three times in total. In group CII, the corneal central zone was soaked in the collagenase type II solution (200 μL of 3 mg/ml) for 30 min. In group CP, the corneas were disposed as group CII firstly, then applied negative pressure as group NP for once after 5 days. All right eyes were treated as control eyes. Corneal morphology and biomechanical related parameters were observed in vivo once a week for three weeks after treatment and before execution. Histology and biomechanics were tested in vitro at the third month after treatment.Results: Corneal diopter and corneal central thickness (CCT) changed to some extent after treatment immediately as a result of negative pressure in group NP. Three months after treatment, their elastic modulus increased and the relaxation degree decreased compared with the control one. In Group CII, corneal diopter increased, CCT and CH decreased at the second week after treatment, which showed the characters of ectatic corneas. At the third month after treatment, elastic modulus (E L ) of the experimental eyes decreased slightly compared with the control eyes. Due to the large individual differences, there were no regular changes on experimental corneas in Group CP.Conclusions: Cornea socked with collagenase type II showed the obvious characteristics of ectatic cornea at the second week after treatment, but the characteristics disappeared gradually. Negative pressure can result in the change of corneal thickness and diopter in a short period of time, and the degree of swelling and duration are far less than Group CII, but the changes of biomechanical parameters are more obviously than Group CII.

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Combination of Violet Light Irradiation and Collagenase Treatments in a Rabbit Model of Keratoconus

10.21203/rs.3.rs-1106934/v1 ◽

2021 ◽

Author(s):

Hidenaga Kobashi ◽

Takashi Yano ◽

Kazuo Tsubota

Keyword(s):

Elastic Modulus ◽

Axial Length ◽

Corneal Thickness ◽

Rabbit Model ◽

Corneal Astigmatism ◽

Elastic Behaviour ◽

Control Group ◽

Violet Light ◽

Collagenase Treatment ◽

Significant Difference

Abstract Purpose: We evaluated the use of collagenase treatment to generate a rabbit model of keratoconus and the impact of violet light (VL) irradiation on the disease model in six Japanese White rabbits. Methods: After epithelial debridement, the collagenase group was treated with a collagenase type II solution for 30 min; the control group was treated with a solution without collagenase. Three rabbits also underwent VL irradiation (375 nm, irradiance 310 μW/cm2) for 3 hours daily for 7 days after topical collagenase application. Slit-lamp microscopy results, steep keratometry (Ks), corneal astigmatism, central corneal thickness, and axial length were examined before and after the procedure. The corneas were obtained on day 7 for biomechanical evaluation. Results: A significant increase in Ks and corneal astigmatism was observed in the collagenase and VL irradiation groups compared with the control group at day 7. No significant difference was found in the change in corneal thickness between the groups. The elastic modulus at 10% strain, but not at 3% and 5% strain, was significantly lower in the collagenase group than in the control group. There was no significant difference in the elastic modulus at each level of strain between the collagenase and VL irradiation groups. The average axial length at day 7 was significantly longer in the collagenase group than in the control group. Collagenase treatment induced a keratoconic model by steepening the keratometric and astigmatic values. There was no significant difference in the observed elastic behaviour of normal and ectatic corneas under physiologically relevant stress levels. Conclusion: VL irradiation did not cause regression of corneal steepening in collagenase-induced model during short-term observation.

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Investigating the Effect of Cognitive-behavioral Stress Management on Occupational Performance among Women with Breast Cancer

Current Women s Health Reviews ◽

10.2174/1573404816666191220095123 ◽

2020 ◽

Vol 16 (2) ◽

pp. 152-159

Author(s):

Arezoo Shayan ◽

Mansoureh Refaei ◽

Farkhondeh Jamshidi

Keyword(s):

Breast Cancer ◽

Stress Management ◽

Repeated Measures ◽

Intervention Group ◽

Performance Measure ◽

Cognitive Behavioral ◽

Occupational Performance ◽

Cognitive Behavioral Stress Management ◽

Behavioral Stress ◽

Significant Difference

Background: Treatment of breast cancer can be accompanied by long-term consequences affecting women’s participation in many tasks. Objective: This study aimed to assess the effect of cognitive behavioral stress management (CBSM) program on occupational performance of women with breast cancer. Methods: In this randomized clinical trial, conducted between Feb 3 and Oct 26, 2016, 104 women with breast cancer who had referred to Imam Khomeini clinic in Hamadan, and who fulfilled the inclusion criteria (20-60 years old, married, suffering from grade 1-3 breast cancer with a history of recent surgery) were enrolled. They were randomly divided into two groups of 52 using a permuted block size of four. The intervention group took part in four 60-minute sessions of CBSM over four weeks. The study data were collected using a demographic information form and the Canadian Occupational Performance Measure. The statistical analyst was masked to intervention allocation. The data were analyzed using descriptive statistics, paired t-test, and repeated measures ANOVA. Results: A significant difference was observed between the two groups regarding the mean scores of occupational performance (p=0.02) and satisfaction (p=0.005) after the intervention. Each variable was measured at three time points (before the intervention, immediately and 2 weeks after intervention). A significant difference was observed in the two groups’ mean scores of performance (p=0.026) and satisfaction (p=0.01), irrespective of the time of assessment. Conclusion: The CBSM program promoted the occupational performance immediately and two weeks after the intervention in women with breast cancer. This technique can be used as a complementary method alongside medical therapies in oncology centers.

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Supercooling Points of Adult Dermacentor variabilis (Acari: Ixodidae) From a Population Near the Northern Distribution Limit

Journal of Medical Entomology ◽

10.1093/jme/tjaa223 ◽

2020 ◽

Author(s):

Matthew E M Yunik ◽

Neil B Chilton

Keyword(s):

Cold Hardiness ◽

Dermacentor Variabilis ◽

Subzero Temperatures ◽

Host Seeking ◽

Short Period ◽

Significant Difference ◽

Northern Distribution ◽

Dog Tick ◽

Provincial Park ◽

Established Population

Abstract The northern distributional limit of Dermacentor variabilis Say, the American dog tick, is expanding in Saskatchewan and Manitoba (western Canada). The ability of D. variabilis to continue to expand its range northwards will depend upon the ability of individuals within populations at the species distributional edge to withstand very low temperatures during winter. One component of cold hardiness is the supercooling point (SCP), the temperature below 0°C at which an individual freezes. In this study, the SCP was determined for 94 questing D. variabilis adults (44 females and 50 males) from an established population near Blackstrap Provincial Park in Saskatchewan. SCP values ranged from −18.2 to −6.7°C, with a median of −13.3°C. This suggests that host-seeking D. variabilis adults differ in their ability to survive exposure to subzero temperatures, for at least a short period of time, without freezing. The distribution of SCPs was bimodal, but there was no significant difference in SCP values between female and male ticks, and no relationship between SCP and tick body weight. It remains to be determined what factors contribute to the variation in SCP values among questing D. variabilis adults.

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Analysis of sagittal profile and radiographic parameters in symptomatic thoracolumbar disc herniation patients

BMC Musculoskeletal Disorders ◽

10.1186/s12891-021-04033-x ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Ang Gao ◽

Yongqiang Wang ◽

Miao Yu ◽

Xiaoguang Liu

Keyword(s):

Disc Herniation ◽

Thoracic Spine ◽

Normal Population ◽

Sagittal Profile ◽

Sacral Slope ◽

Type I ◽

Type Ii ◽

Radiographic Parameters ◽

Significant Difference ◽

Thoracolumbar Region

Abstract Background Few studies describe thoracolumbar disc herniation (TLDH) as an isolated category, it is frequently classified as the lower thoracic spine or upper lumbar spine. Thus, less is known about the morphology and aetiology of TLDH compared to lumbar disc herniation (LDH). The aim of study is to investigate sagittal alignment in TLDH and analyze sagittal profile with radiographic parameters. Methods Data from 70 patients diagnosed with TLDH were retrospectively reviewed. The thoracic-lumbar alignment was depicted by description of curvatures (the apex of lumbar curvature, the apex of thoracic curvature, and inflexion point of the two curvatures) and radiographic parameters from complete standing long-cassette spine radiographs. The rank sum test was utilised to compare radiographic parameter values in each subtype. Results We found two subtypes differentiated by the apex of thoracic kyphotic curves. The sagittal profile was similar to that of the normal population in type I, presenting the apex of the thoracic kyphotic curve located in the middle thoracic spine. The well aligned thoracic-lumbar curve was disrupted in type II, presenting the apex of the thoracic kyphotic curve located in the thoracolumbar region in type II patients. Thirty-six patients were classified as type I, and 34 patients were classified as type II. The mean sagittal vertical axis, T1 pelvic angle and L1 pelvic angle were 27.9 ± 24.8°, 8.2 ± 7.3° and 6.2 ± 4.9°, respectively. There was significant difference (p < 0.001) of thoracolumbar angle between type I (14.9 ± 7.9°) and type II patients (29.1 ± 13.7°). Conclusions We presented two distinctive sagittal profiles in TLDH patients, and a regional kyphotic deformity with a balanced spine was validated in both subtypes. In type I patients, disc degeneration was accelerated by regional kyphosis in the thoracolumbar junction and eventually caused disc herniation. In type II patients, excessive mechanical stress was directly loaded at the top of the curve (thoracolumbar apex region) rather than being diverted by an arc as in a normal population or type I patients. Mismatch between shape and sacral slope value was observed, and better agreement was found in Type II patients.

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Cytotoxicity assessment of different doses of ozonated water on dental pulp cells

BMC Oral Health ◽

10.1186/s12903-021-01392-8 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Ferdiye Küçük ◽

Sibel Yıldırım ◽

Serap Çetiner

Keyword(s):

Cell Viability ◽

Repeated Measures ◽

Dental Pulp ◽

Control Group ◽

Dental Pulp Cells ◽

Time Points ◽

Significant Difference ◽

Pulp Cells ◽

Time Point ◽

Ozonated Water

Abstract Background The purpose of this study was to assess the cytotoxicity of various concentrations of ozonated water (OW) on human primary dental pulp cells. Methods Human primary dental pulp cells were isolated from exfoliated primary canine teeth of an 11-year-old patient with good systemic and oral health. Afterwards, cells were divided into 6 experimental groups; four groups of OW in concentrations of 2 mg/L, 4 mg/L, 8 mg/L, and 16 mg/L, untreated control group, and cell culture without cells. Cytotoxicity was evaluated after exposure for 5-min exposure using Mosmann’s Tetrazolium Toxicity (MTT) assay at 0 h and 48 h time points. Data were analyzed using a repeated measures analysis of variance and Post-hoc tests were performed using Bonferroni correction for multiple comparisons. Results All experimental groups showed proliferation at 0 h time point. However, all groups also experienced a decrease in overtime at 48 h time point (p < 0.05). At both time points 2 mg/L OW showed the highest cell viability as well as proliferation. At 0 h time point, the increase in cell viability for all experimental groups was found statistically significant when compared to positive control group (p < 0.05). At 48 h time point, although 8 mg/L and 16 mg/L OW showed statistically significant reduction in compare to 0 h time point, 2 mg/L and 4 mg/L OW groups didn’t experience any statistically significant difference (p < 0.05). Conclusion Considering our findings, due to ozonated water's induced a higher proliferation rate of dental pulp cells, indicating their biocompatibility and a possible adjuvant on irrigating agent in regenerative endodontic procedures.

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Morphological Changes of the Hip Commonly Associated With Femoroacetabular Impingement Are Not Correlated With Rotational Range of Hip Motion in Elite Soccer Athletes

Sports Health A Multidisciplinary Approach ◽

10.1177/1941738120973662 ◽

2021 ◽

pp. 194173812097366

Author(s):

André Orlandi Bento ◽

Guilherme Falótico ◽

Keelan Enseki ◽

Ronaldo Alves Cunha ◽

Benno Ejnisman ◽

...

Keyword(s):

Femoroacetabular Impingement ◽

Lower Limb ◽

Clinical Relevance ◽

Morphological Changes ◽

Alpha Angle ◽

Soccer Players ◽

Level Of Evidence ◽

Rotational Movement ◽

Professional Soccer ◽

Significant Difference

Background: Morphological changes characteristic of femoroacetabular impingement (FAI) are common in soccer players. However, the clinical relevance of such anatomical variations is still not well-defined. Hypothesis: We hypothesized that high alpha angle values and/or acetabular retroversion index (ARI) are correlated with rotational range of motion (ROM) of the hip and that there are clinical-radiological diferences between the dominant lower limb (DLL) and nondominant lower limb (NDLL) in professional soccer players. Study Design: Cross-sectional. Level of Evidence: Level 3. Methods: A total of 59 male professional soccer players (average age 25.5 years, range 18-38 years) were evaluated in the preseason. As main outcome measures, we evaluated the alpha angle and the ARI and hip IR and ER ROM with radiographic analysis. Results: The measurements taken on DLL and NDLL were compared and a significant difference was found between the sides in the ER ( P = 0.027), where the DLL measures were 1.54° (95% CI, 0.18-2.89) greater than the NDLL. There were no significant differences between the sides in the measures of IR ( P > 0.99), total ROM ( P = 0.07), alpha angle ( P = 0.250), and ARI ( P = 0.079). The correlations between the rotation measurements and the alpha angle in each limb were evaluated and the coefficient values showed no correlation; so also between the ARI and rotation measures. Conclusion: Morphological changes of the femur or acetabulum are not correlated with hip IR and ER ROM in male professional soccer players. ER on the dominant side was greater than on the nondominant side. There was no significant difference in the other measurements between sides. Clinical Relevance: In clinical practice, it is common to attribute loss of hip rotational movement to the presence of FAI. This study shows that anatomical FAI may not have a very strong influence on available hip rotational movement in professional soccer athletes.

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Combining Microfractures, Autologous Bone Graft, and Autologous Matrix-Induced Chondrogenesis for the Treatment of Juvenile Osteochondral Talar Lesions

Foot & Ankle International ◽

10.1177/1071100716687367 ◽

2017 ◽

Vol 38 (5) ◽

pp. 485-495 ◽

Cited By ~ 17

Author(s):

Riccardo D’Ambrosi ◽

Camilla Maccario ◽

Chiara Ursino ◽

Nicola Serra ◽

Federico Giuseppe Usuelli

Keyword(s):

Bone Graft ◽

Repeated Measures ◽

Osteochondral Lesion ◽

Young Patients ◽

Case Series ◽

Autologous Bone Graft ◽

Lesion Size ◽

Level Of Evidence ◽

Significant Difference ◽

Autologous Bone

Background: The purpose of this study was to evaluate the clinical and radiologic outcomes of patients younger than 20 years, treated with the arthroscopic-talus autologous matrix-induced chondrogenesis (AT-AMIC) technique and autologous bone graft for osteochondral lesion of the talus (OLT). Methods: Eleven patients under 20 years (range 13.3-20.0) underwent the AT-AMIC procedure and autologous bone graft for OLTs. Patients were evaluated preoperatively (T0) and at 6 (T1), 12 (T2), and 24 (T3) months postoperatively, using the American Orthopaedic Foot & Ankle Society Ankle and Hindfoot (AOFAS) score, the visual analog scale and the SF-12 respectively in its Mental and Physical Component Scores. Radiologic assessment included computed tomographic (CT) scan, magnetic resonance imaging (MRI) and intraoperative measurement of the lesion. A multivariate statistical analysis was performed. Results: Mean lesion size measured during surgery was 1.1 cm3 ± 0.5 cm3. We found a significant difference in clinical and radiologic parameters with analysis of variance for repeated measures ( P < .001). All clinical scores significantly improved ( P < .05) from T0 to T3. Lesion area significantly reduced from 119.1 ± 29.1 mm2 preoperatively to 77.9 ± 15.8 mm2 ( P < .05) at final follow-up as assessed by CT, and from 132.2 ± 31.3 mm2 to 85.3 ± 14.5 mm2 ( P < .05) as assessed by MRI. Moreover, we noted an important correlation between intraoperative size of the lesion and body mass index (BMI) ( P = .011). Conclusions: The technique can be considered safe and effective with early good results in young patients. Moreover, we demonstrated a significant correlation between BMI and lesion size and a significant impact of OLTs on quality of life. Level of Evidence: Level IV, retrospective case series.

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“Going Backward”: Effects of age and fatigue on posterior-directed falls in Parkinson disease

Neurorehabilitation ◽

10.3233/nre-210040 ◽

2021 ◽

pp. 1-9

Author(s):

Evan V. Papa ◽

Rita M. Patterson ◽

Nicoleta Bugnariu

Keyword(s):

Postural Control ◽

Parkinson Disease ◽

Repeated Measures ◽

Center Of Pressure ◽

Angular Displacement ◽

Reaction Times ◽

Older Individuals ◽

Peak Knee ◽

Significant Difference ◽

Fatiguing Exercise

BACKGROUND: Nearly half of persons with Parkinson disease (PD) report fatigue as a factor in their fall history. However, it is unknown whether these self-reported falls are caused by a sensation of fatigue or performance fatigue. OBJECTIVE: We sought to investigate the influences of performance fatigue and age on postural control in persons with PD. METHODS: Individuals with PD (n = 14) underwent postural control assessments before (T0) and immediately after (T1) fatiguing exercise. Biomechanical data were gathered on participants completing a treadmill-induced, posterior-directed fall. Performance fatigue was produced using lower extremity resistance exercise on an isokinetic ergometer. Repeated measures ANCOVAs were used with age as a covariate to determine the effects of performance fatigue on biomechanical variables. RESULTS: After adjustment for age, there was a statistically significant difference in peak center of pressure (COP) latency during the support phase of recovery. Pairwise comparisons demonstrated a decrease in peak ankle displacement from T0 to T1. Age was also found to be significantly related to reaction time and peak knee displacement while participants were fatigued. CONCLUSIONS: The decreased peak COP latency, along with decreased ankle angular displacement, suggest that persons with PD adopt a stiffening strategy in response to backward directed falls. Postural stiffening is not uncommon in persons with PD and could be a risk factor for falls. Older individuals with PD demonstrate slower mobility scores and decreased reaction times in the setting of fatigue, suggesting a combined effect of the aging and fatigue processes.

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