A Case Series of 36 Patients Treated for Old World Cutaneous leishmaniasis.

Background: Cutaneous leishmaniasis is endemic in Iran. Objective: We sought to investigate the therapeutic outcomes and complications of treatment in patients with cutaneous leishmaniasis. Methods: This case series enrolled patients with smear-proven cutaneous leishmaniasis who visited our center in Iran from 2018 to 2019. Results: In total, 36 patients were treated with intralesional meglumine antimoniate, intramuscular meglumine antimoniate, sodium stibogluconate, and amphotericin B. Overall, this treatment was effective in 81.8 percent of patients. Relapse and treatment failure occurred in 6.1 percent and 12.1 percent of patients, respectively. Treatment with intralesional meglumine antimoniate, intramuscular meglumine antimoniate, sodium stibogluconate, and amphotericin B yielded a clearance rate of 80.8 percent, 92.3 percent, 75 percent, and 85.7 percent, respectively. Clearance was associated with a shorter time interval between injections of intralesional meglumine antimoniate (p=0.006) and relapse was associated with a longer time interval between injections (p=0.018). The average number of side effects per patient for intralesional meglumine antimoniate, sodium stibogluconate, intramuscular meglumine antimoniate, and amphotericin B was 0.62, 1.4, 1.6, and 2.8, respectively. The most common side effect of intralesional meglumine antimoniate, intramuscular meglumine antimoniate, and amphotericin B was local pain, arthralgia, and hypokalemia, respectively. Limitations: Low sample size was the limitation of this study. Conclusion: The cure rate of intramuscular meglumine antimoniate was higher than amphotericin B, which was higher than the cure rate of sodium stibogluconate. In patients treated with intralesional meglumine antimoniate, reducing the time interval between injections increased the clearance rate and decreased the rate of relapse.

Whole-Transcriptome Sequencing-Based Profiling of the Cutaneous Virome in Patients with Secondary Immunodeficiency.

Most viral infections can be self-limited, with no requirement for medical intervention. However, the same viruses can cause severe diseases in patients with compromised immunity due to single-gene diseases, acquired immune deficiency syndrome, or hematologic malignancies or those receiving immunosuppressive drugs. Occasionally, these immunocompromised patients harbor >1 infectious agent, requiring several concomitant diagnostic tests. We have developed, to our knowledge, a previously unreported whole-transcriptome sequencing-based pipeline that allows virome profiling, quantitation, and expression pattern analysis of 926 distinct viruses by sequencing of RNA isolated from a single lesional skin biopsy. This pipeline can also explore host genetics if there is a Mendelian predisposition to infection. We applied this pipeline to 6 Iranian patients with viral-induced skin lesions associated with immune deficiency secondary to HIV, human T-lymphotropic virus 1, chronic lymphocytic leukemia, and post transplant immunosuppression. In 5 cases, definitive human papillomavirus infections were identified, some caused by multiple viral types. In addition to human papillomavirus, coinfection with other viruses (Merkle cell polyomavirus, cytomegalovirus, and human herpesvirus 4) was detected in some lesions. In 1 case, whole-transcriptome sequencing validated the clinical diagnosis of adult T-cell leukemia/lymphoma in a patient with an initial diagnosis of mycosis fungoides/Sézary syndrome. These findings attest to the power of whole-transcriptome sequencing in profiling the cutaneous virome in the context of compromised immunity.

Application of Menstrual Blood Derived Stromal (stem) Cells Exert Greater Regenerative Potency Than Fibroblasts/Keratinocytes in Chronic Wounds of Diabetic Mice.

Background: In this study we differentially showed the effects of cell-seeded bilayer scaffold wound dressing in accelerating healing process in diabetic ulcers that still remains as a major clinical challenge. The aim of the study was to compare immunomodulatory and angiogenic activity, and regenerative effect differences between Menstrual blood-derived Stem Cells (MenSCs) and foreskin-derived keratinocytes/fibroblasts. Methods: The streptozotocin-induced diabetic mice model was developed in male C57/BL6 mice. A bilayer scaffold was fabricated by electrospining silk fibroin nano-fibers on human Amniotic Membrane (AM). Dermal fibroblasts and keratinocyte isolated from neonatal foreskin and MenSCs were isolated from the menstrual blood of healthy women. The diabetic mice were randomly divided into three groups including no treatment group, fibroblast/keratinocyte-seeded bilayer scaffold group (bSC+FK), and MenSCs-seeded bilayer scaffold group. The healing of full-thickness excisional wounds evaluations in the diabetic mice model in each group were evaluated at 3, 7, and 14 days after treatment. Results: The gross and histological data sets significantly showed wound healing promotion via re-epithelialization and wound contraction along with enhanced regeneration in MenSCs-seeded bilayer scaffold group with the most similarity to adjacent intact tissue. Immunofluorescence staining of mouse skin depicted a descending trend of type III collagen along with the higher expression of involucrin as keratinocyte marker in the MenSCs-seeded bilayer nanofibrous scaffold group in comparison with other treatment groups from day 7 to day 14. Moreover, higher levels of CD31 and von Willebrand factor (VWF), and also a higher ratio of M2/M1 macrophages in association with higher levels of the neural marker were observed in the bSC+MenSCs group in comparison with bSC+FK and no treatment groups. Conclusion: Healing symptoms in wounds dressed with keratinocyte/fibroblast-seeded bilayer scaffold was significantly lower than MenSCs-seeded bilayer scaffold done on impaired diabetic wound chronicity.

Serologic Biomarkers in Pemphigus Monitoring: C-reactive Protein, Macrophage Migration Inhibitory Factor, and Prolactin Levels Versus Autoantibody Assays.

Evaluation and monitoring of pemphigus vulgaris (PV) typically involve autoantibody detection by enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IIF). We aimed to determine the levels of antipemphigus immunoglobulin (Ig) G autoantibodies using ELISA and IIF (as standard biomarkers), and compare it to prolactin, macrophage migration inhibitory factor (MIF), and C-reactive protein (CRP) (as nonstandard biomarkers) to determine which of these non-standard biomarkers is appropriate for PV monitoring. The experiment was performed before and during therapy. Anti-Dsg immunoglobulin G autoantibodies were measured using ELISA and IIF (as standard biomarkers) versus prolactin, MIF, and CRP (nonstandard), before 1 and 3 months after the treatment. Before beginning the treatment, the severity of the disease was determined using the pemphigus disease area Index (PDAI). We enrolled 60 newly diagnosed patients with PV (32 men and 28 women; mean age=43.8±14.2 years). Before treatment, the levels of anti-Dsg1, anti-Dsg3, and IIF were high and had a significant relationship with PDAI. PDAI also had a connection with the levels of CRP and prolactin. The anti-Dsg1, anti-Dsg3, IIF, and CRP titers decreased in patients treated with conventional (prednisolone plus azathioprine) and rituximab therapy during and after treatment. In conclusion, anti-Dsg1, anti-Dsg3, and IIF autoantibody titers remain standard biomarkers for assessing disease activity, severity, and PV monitoring. The trend of CRP was similar to that of anti-Dsg1, anti-Dsg3, and IIF. Thus, CRP may be used for PV monitoring.

The Relationship Between ABO and Rh Blood Groups with Alopecia Areata.

INTRODUCTION: Alopecia areata (AA) is a common non-scaring hair loss disease. Genetic susceptibility and environmental factors can develop the disease. OBJECTIVES: We investigated the association between AA and ABO and Rh blood groups. METHODS: This cross-sectional study was done on 200 patients with AA and 200 healthy controls (HCs) between March 2021 and September 2021. RESULTS: The prevalence of blood groups O, A, B, and AB in patients with AA was 30%, 30.5%, 10.5%, and 29%, respectively. A significant difference was detected between the two groups in the frequency of the ABO and ABO*Rh blood groups (p-value < 0.05). Compared to the HCs, the prevalence of the AB and AB+ blood group was higher in AA patients. No significant relationship was detected between sex, BMI, duration of disease, age at onset, severity of alopecia tool (SALT) score, hair loss pattern, and nail involvement with ABO and Rh blood groups (p-value > 0.05). CONCLUSION: In conclusion, the highest difference was related to the AB+ blood group, so compared to HCs, the AB+ blood group frequency was higher in patients with AA. However, more studies with larger sample sizes on different ethnicities should be performed to verify the results of this study.

Intraovarian Administration of Autologous Menstrual Blood Derived-Mesenchymal Stromal Cells in Women with Premature Ovarian Failure.

BACKGROUND: Premature ovarian failure (POF) is a well-known cause of infertility, particularly in women under the age of 40. POF is also associated with elevated gonadotropin levels, amenorrhea and sex-hormone deficiency. AIM OF THE STUDY: In this study, the therapeutic potential of autologous mesenchymal stromal cells obtained from menstrual blood (Men-MSCs) for patients with POF was evaluated. METHODS: 15 POF patients were included in the study. The cultured Men-MSCs were confirmed by flow cytometry, karyotype, endotoxin and mycoplasma and were then injected into the patients' right ovary by vaginal ultrasound guidance and under general anesthesia and aseptic conditions. Changes in patients' anti-Müllerian hormone (AMH), antral follicle count (AFC), follicle-stimulating hormone (FSH), luteal hormone (LH), and estradiol (E2) levels, as well as general flushing and vaginal dryness were followed up to one year after treatment. RESULTS: All patients were satisfied with a decrease in general flushing and vaginal dryness. 4 patients (2.9%) showed a spontaneous return of menstruation without additional pharmacological treatment. There was a significant difference in AFC (0 vs. 1 ± 0.92 count, p value ≤0.001%), FSH (74 ± 22.9 vs. 54.8 ± 17.5 mIU/mL, p-value ≤0.05%), E2 (10.2 ± 6 vs. 21.8 ± 11.5 pg/mL p-value ≤0.01%), LH (74 ± 22.9 vs. 54.8 ± 17.5 IU/L,p-value ≤0.01%) during 3 months post-injection. However, there were no significant changes in AMH (p-value ≥0.05%). There were also no significant differences in assessed parameters between 3 and 6 months after cell injection. CONCLUSION: According to the findings of this study, administration of Men-MSCs improved ovarian function and menstrual restoration in some POF patients.

Whole transcriptome-based skin virome profiling in typical epidermodysplasia verruciformis reveals α-, ß-, and γ-HPV infections.

HPVs are DNA viruses include approximately 450 types that are classified into 5 genera (α-, ß-, γ-, µ-, and ν-HPV). The γ- and ß-HPVs are present in low copy numbers in healthy individuals; however, in patients with an inborn error of immunity, certain species of ß-HPVs can cause epidermodysplasia verruciformis (EV), manifesting as recalcitrant cutaneous warts and skin cancer. EV presents as either typical or atypical. Manifestations of typical EV are limited to the skin and are caused by abnormal keratinocyte-intrinsic immunity to ß-HPVs due to pathogenic sequence variants in TMC6, TMC8, or CIB1. We applied a transcriptome-based computational pipeline, VirPy, to RNA extracted from normal-appearing skin and wart samples of patients with typical EV to explore the viral and human genetic determinants. In 26 patients, 9 distinct biallelic mutations were detected in TMC6, TMC8, and CIB1, 7 of which are previously unreported to our knowledge. Additionally, 20 different HPV species, including 3 α-HPVs, 16 ß-HPVs, and 1 γ-HPV, were detected, 8 of which are reported here for the first time to our knowledge in patients with EV (ß-HPV-37, -47, -80, -151, and -159; α-HPV-2 and -57; and γ-HPV-128). This study expands the TMC6, TMC8, and CIB1 sequence variant spectrum and implicates new HPV subtypes in the pathogenesis of typical EV.

Clinical Characteristics and Treatment Outcomes of Scleromyxedema: A 10-Year Retrospective Survey.

Scleromyxedema is a rare but important mucinosis disorder of the skin that is presented with dermatological manifestations such as waxy papules, diffuse induration, and nondermatologic involvements like neurological and renal disorders. We report a case series of the data regarding the characteristics and treatment of 14 patients diagnosed with scleromyxedema and their follow-up. Patients entered the study based on scleromyxedema diagnosis criteria. Comorbidities were also recorded to evaluate their effect on the treatment process. Clinicopathological and laboratory findings and responses to their treatment were evaluated separately. There was a significant improvement after administering intravenous immunoglobulin (IVIG). Despite the lack of a definite treatment for this condition, the present study shows that the application of IVIG can improve both cutaneous and systemic symptoms. Younger patients, in particular, responded significantly to the use of IVIG. More studies are required to investigate the potential efficacy of IVIG in the treatment of scleromyxedema.

Sleep disturbance in alopecia areata: A cross-sectional study.

Background: Alopecia areata (AA) is a nonscarring hair loss with autoimmune pathophysiology, which is associated with psychiatric disorders including anxiety and depression. Sleep disorders are commonly seen with anxiety and depression. Here we evaluate the sleep quality of AA patients. Methods: This cross-sectional study involved 51 AA patients and 51 age- and sex-matched healthy controls. The sleep quality and day sleepiness were evaluated by the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) questionnaires. The severity of AA was evaluated with the Severity of Alopecia Tool (SALT). Results: Unlike the ESS score, the mean PSQI score was significantly higher in the AA group compared with the controls (7 ± 4.13 vs. 3.53 ± 1.96, p < 0.001). The number of cases with ESS ≥ 11, indicating the excess daytime sleepiness, was significantly higher in the AA group compared with controls (15 vs. 6, p = 0.02). There was no significant correlation between PSQI score and age, age of onset of the disease, or SALT score (p > 0.05). Anxiety and depression were more common in the AA group versus controls (p = 0.9). PSQI score was higher in AA patients who had anxiety and depression compared with those who did not (9.9 ± 5.28 vs. 4.76 ± 3.08, p = 0.001). Conclusion: Sleep quality is impaired in AA patients. As expected, sleep would be more disturbed in AA cases with depression or anxiety. Therefore, attention to sleep quality and concomitant psychiatric diseases is essential in AA clinical management.

Recalcitrant Cutaneous Warts in a Family with Inherited ICOS Deficiency.

Recalcitrant warts, caused by human papillomaviruses (HPVs), can be a cutaneous manifestation of inborn error of immunity. This study investigated the clinical manifestations, immunodeficiency, single-gene susceptibility, and HPV repertoire in a consanguineous family with severe sinopulmonary infections and recalcitrant warts. Clinical and immunologic evaluations, including FACS and lymphocyte transformation test, provided evidence for immunodeficiency. Combined whole-exome sequencing and genome-wide homozygosity mapping were utilized to disclose candidate sequence variants. Whole-transcriptome sequencing was used to concomitantly investigate the HPV genotypes and the consequences of detected sequence variants in the host. The proband, a male aged 41 years, was found to be homozygous for the c.6delG, p.Lys2Asnfs∗17 variant in ICOS, encoding the inducible T-cell costimulator. This variant was located inside the 5 megabase of runs of homozygosity on 2q33.2. RNA sequencing confirmed the deleteriousness of the ICOS variant in three skin biopsies revealing significant downregulation of ICOS and its ligand, ICOSLG. Reads unaligned to the human genome were applied to 926 different viruses, and α-HPV57, ß-HPV107, ß-HPV14, and ß-HPV17 were detected. Collectively, we describe a previously unrecognized inborn error of T-cell immunity to HPVs, indicating that autosomal recessive ICOS deficiency can underlie recalcitrant warts, emphasizing the immunologic underpinnings of recalcitrant warts at the nexus of human and viral genomic variation.

Whole-transcriptome sequencing-based concomitant detection of viral and human genetic determinants of cutaneous lesions.

Severe viral infections of the skin can occur in patients with inborn errors of immunity (IEI). We report an all-in-one whole-transcriptome sequencing-based method by RNA-Seq on a single skin biopsy for concomitantly identifying the cutaneous virome and the underlying IEI. Skin biopsies were obtained from healthy and lesional skin from patients with cutaneous infections suspected to be of viral origin. RNA-Seq was utilized as the first-tier strategy for unbiased human genome-wide rare variant detection. Reads unaligned to the human genome were utilized for the exploration of 926 viruses in a viral genome catalog. In 9 families studied, the patients carried pathogenic variants in 6 human IEI genes, including IL2RG, WAS, CIB1, STK4, GATA2, and DOCK8. Gene expression profiling also confirmed pathogenicity of the human variants and permitted genome-wide homozygosity mapping, which assisted in identification of candidate genes in consanguineous families. This automated, online, all-in-one computational pipeline, called VirPy, enables simultaneous detection of the viral triggers and the human genetic variants underlying skin lesions in patients with suspected IEI and viral dermatosis.

The remarkable effect of menstrual blood stem cells seeded on bilayer scaffold composed of amniotic membrane and silk fibroin aiming to promote wound healing in diabetic mice.

INTRODUCTION: Impaired chronic wound healing frequently occurs in diabetic patients. We hypothesized that menstrual blood-derived mesenchymal stem cells (MenSCs) in combination with bilayer scaffold consisted of human amniotic membrane (AM) and electrospun silk fibroin nanofibers could potentially promote wound healing in diabetic mice. METHODS & METHODS: Two bilateral full-thickness wounds were created on dorsal skin of type-1 diabetic mice model and animals were equally divided in four groups including: no-treatment group (NT), amniotic membrane treated group (AM), bilayer scaffold treated group (bSC), and MenSCs-seeded bilayer scaffold treated group (bSC + MenSCs). Wound healing evaluations were performed at 3, 7, and 14 days after their treatment. The wound healing was analyzed by macroscopic and microscopic evaluations, and immunofluorescence staining of involucrin (IVL), type III collagen, CD31/ von Willebrand factor (vWF), and PGP9.5 were performed. Furthermore, number of neutrophils and macrophages and subpopulation of macrophages were assessed. In addition, the expression of Egr2, Mmp9, CXCL12, IDO1, Ptgs2 and VEGFA transcripts involved in wound repair were also analyzed. RESULTS: After 14 days, the best epidermal and dermal regeneration belonged to the cases received bSC + MenSCs as wound dressing. Moreover, the wound healing was typically faster in this group compared to other groups. Immunofluorescence evaluation represented higher levels of CD31 and VWF, higher ratio of M2/M1 macrophages, greater expression of IVL, and higher levels of the PGP9.5 in the bSC + MenSCs group in comparison with other groups. Expression analysis of assessed genes also supported assumption of more regeneration and healing in the bSC + MenSCs group versus other groups. CONCLUSION: These results indicate that enhanced immunomodulatory and reparative properties of MenSCs in conjunction with bilayer scaffold specified this cellular skin substitute for modulating wound chronicity and contribution to resolution of wound healing process in diabetic ulcer.

Recalcitrant Warts, Epidermodysplasia Verruciformis, and the Tree-Man Syndrome: Phenotypic Spectrum of Cutaneous Human Papillomavirus Infections at the Intersection of Genetic Variability of Viral and Human Genomes.

Human papillomavirus (HPV) infections can cause common warts, which usually resolve spontaneously or become recalcitrant, resistant to multiple treatments. In rare cases, they transform into cutaneous giant horns resulting in the tree-man syndrome (TMS). Defective ß-HPVs can cause flat warts in epidermodysplasia verruciformis (EV), a genetic disorder. In typical EV, limited to the skin, the mutated genes are critical for keratinocyte-intrinsic immunity, whereas atypical, syndromic EV involves genes controlling T cells. Inborn errors of immunity due to mutations in distinct genes underlying recalcitrant warts and the α-HPV2‒driven TMS have been identified, all disrupting T-cell immunity. Collectively, these observations attest to the wide phenotypic spectrum of cutaneous infections caused by different HPV types at the intersection of the genetic diversity of the viral and human genomes.

Contribution of HLA class II genes, DRB4*01:01, DRB1*07:01, and DQB1*03:03:2 to clinical features of Vitiligo disease in Iranian population.

BACKGROUND: Vitiligo is a multifactorial depigmentation condition, which is due to skin melanocyte destruction. Increased expression of HLA class II genes in patients with pre-lesions of Vitiligo suggests a crucial role for the participation of immune response in Vitiligo development. Recent studies progressively focused on HLA-DRB1 and DQB1 genes. In this study, we have evaluated the association and role of HLA-DRB4*01:01, -DRB1*07:01, and -DQB1*03:03:2 genes in different clinical subtypes of Vitiligo in the Iranian population. METHODS: First, Genomic DNA from peripheral blood of 125 unrelated Vitiligo patients and 100 unrelated healthy controls were extracted through the salting-out method. Then, HLA class II genotyping was performed using the sequence-specific primer PCR method. Finally, the clinical relevance of the testing for these genotypes was evaluated by applying the PcPPV (prevalence-corrected positive predictive value) formula. RESULTS: Our results indicated the positive associations of DRB4*01:01 and DRB1*07:01 allelic genes with early-onset Vitiligo (p = 0.024 and 0.022, respectively). DRB4*01:01 also showed strong protection against late-onset Vitiligo (p = 0.0016, RR = 0.360). Moreover, our data revealed that the DRB1*07:01 increases the susceptibility to Sporadic Vitiligo (p = 0.030, RR = 1.702). Furthermore, our findings proposed that elevated vulnerability of Vitiligo patients due to DRB4*01:01 and DRB1*07:01 alleles maybe is correlated with the presence of amino acid Arginine at position 71 at pocket 4 on the antigen-binding site of the HLA-DRB1 receptor. CONCLUSION: Our findings on different subtypes of Vitiligo suggest that, despite a more apparent autoimmune involvement, a non-autoimmune nature for the etiology of Vitiligo should also be considered.

Electrophysiological studies in patients with seropositive/seronegative myasthenia gravis.

Background: Myasthenia gravis (MG) affects the neuromuscular transmission, causing fluctuating muscle weakness and fatigue. This study is carried out with the aim to study the electrophysiologic findings of different subtypes of MG referred to our center in Tehran, Iran. Methods: All patients with MG presenting to neurology department of Shariati Hospital, Tehran University of Medical Sciences were enrolled. Clinically, patients with MG were categorized as ocular vs. generalized. The acetylcholine receptor (Ach-R) and muscle-specific receptor tyrosine kinase (anti-MuSK) antibodies were performed. Repetitive Nerve Stimulation (RNS) was performed using the standard method, with supramaximal stimulation of muscles at the 3 Hz frequency by surface electrode at rest. Abductor pollicis brevis (APB) (median nerve), anconeus (radial nerve), trapezius (accessory nerve), and nasalis (facial nerve) muscles were studied in all patients. Single fiber electromyography (SFEMG) was performed by standard method. Results: 196 seropositive patients with MG were included in the study. In electrophysiological studies, RNS was performed for 146 patients of Ach-R-Ab positive MG, with positive results in 110 patients. In addition, SFEMG was conducted for 8 patients with negative RNS, which resulted in 7 positive tests. Among 23 patients with anti-MuSK-positive MG, RNS was performed for 16 patients, with positive results in 11 patients. The 5 remaining patients with negative RNS test were studied by SFEMG, 4 of whom had positive results. APB compound muscle action potential (CMAP) decrementation significantly correlated with Ach-R-Ab positive MG (P < 0.03). Conclusion: This finding can support the hypothesis that the selection of muscles in electrodignostic study would be important. The electrodiagnostic studies are a good and non-invasive diagnostic tool for MG, and a combination of different distal, proximal, and facial muscles can increase the overall sensitivity of the test.

Safety and efficacy of engineered tissue composed of silk fibroin/collagen and autologous chondrocytes in two patients with cartilage defects: A pilot clinical trial study.

BACKGROUND: The objective of this pilot clinical trial study was to evaluate safety and effectiveness of the newly engineered tissue composed of autologous chondrocytes and collagen/fibroin scaffold in repair of osteochondral defects. METHODS: We implemented a pilot clinical study in two patients with knee osteochondral lesions using engineered tissue composed of scaffold and autologous chondrocytes. Patients were clinically evaluated using the International Repair Cartilage Society score and magnetic resonance imaging (MRI) for one year. RESULTS: Improved clinical outcomes and objective scores indicated a normal or nearly normal knee in both patients. International Knee Documentation Committee score was upgraded from 34.5 at baseline to 72.4 in the first patient, and 28.7 to 81.6 in the second patient. Visual analogue scale, showing the suffering pain score, was lowered from 8 to 0 in both patients, Western Ontario and McMaster Universities Osteoarthritis Index score representing the physical ability of the patients was changed from 68.1 to 87.1 in Patient 1 and 58.3 to 87.1 in Patient 2, the knee function score, related to the functional ability of the knee, was improved from 70 to 100 in the first patient and from 45 to 91 in the second patient. MRI showed great coverage and integration of the graft in patients, with no effusion, decreased edema and cartilage formation signals. CONCLUSIONS: The functional and clinical outcomes alongside MRI data showed promising results for regenerating osteochondral defects. A randomized clinical trial study is required to confirm feasibility of this novel engineered tissue in repair of osteochondral defects.