Systematic description of COVID-19 pandemic using exact SIR solutions and Gumbel distributions.

An epidemiological study is carried out in several countries analyzing the first wave of the COVID-19 pandemic using the SIR model and Gumbel distribution. The equations of the SIR model are solved exactly using the proper time as a parameter. The physical time is obtained by integration of the inverse of the infected function over proper time. Some properties of the solutions of the SIR model are studied such as time scaling and the asymmetry, which allows to obtain the basic reproduction number from the data. Approximations to the solutions of the SIR model are studied using Gumbel distributions by least squares fit or by adjusting the maximum of the infected function. Finally, the parameters of the SIR model and the Gumbel function are extracted from the death data and compared for the different countries. It is found that ten of the selected countries are very well described by the solutions of the SIR model, with a basic reproduction number between 3 and 8.

Impact of BK Polyomavirus Plasma Viral Load in Kidney Transplant Outcomes.

BACKGROUND: BK polyomavirus infection (BKVi) is an important cause of kidney transplant (KT) loss, but there is scarce evidence on the impact of BK plasma viral load on graft function and long-term KT survival. METHODS: A retrospective cohort study including all KT recipients with BKVi (BK viremia identified in ≥3 consecutive samples by polymerase chain reaction) in our center from January 2010 to December 2020 was performed. A case-control study (1:2) was performed. We grouped the cases according to their highest peak viral load: low-level viremia (<10,000 copies/mL) and high-level viremia (≥10,000 copies/mL). To identify risk factors for BKVi, a logistic regression analysis was achieved, and a multivariable Cox regression was used to describe risk factors for graft loss. RESULTS: A total of 849 KTs were performed, and 67 presented BKVi (low-level viremia, n = 35 and high-level viremia, n = 26). In logistic regression analysis male sex (odds ratio [OR], 4.226; 95% CI, 1.660-10.758, P = .002), age (OR, 1.047; 95% CI, 1.008-1.088; P = .018), and retransplant (OR, 4.162; 95% CI, 1.018-17.015; P = .047) were predictors of BKVi. Acute rejection was more frequent in the BKVi group (18% vs 4.9%, P = .004), and graft survival was lower in patients with BKVi and high-level viremia (P = .027). In Cox regression analysis, BKVi (hazard ratio, 3.657; 95% CI, 1.146-11.670; P = .029) and specific BKV (BK polyomavirus) high-level viremia (hazard ratio, 1.988; 95% CI, 1.012-3.907; P = .046) were predictors of shorter graft survival. CONCLUSIONS: BKV high-level viremia was associated with BKV nephropathy and poorer graft survival. Additionally, acute rejection is more frequent after BKVi. It is necessary to develop strategies safe and effective for these patients.

The ultrastructure of muscle fibers and satellite cells in experimental autoimmune encephalomyelitis after treatment with transcranial magnetic stimulation.

In this study, we investigated the effect of transcranial magnetic stimulation (TMS) on the ultrastructure of muscle fibers and satellite cells in rats with experimental autoimmune encephalomyelitis (EAE). EAE-induced animals were treated with TMS (60 Hz at 0.7 mT) for 2 hours in the morning, once a day, 5 days a week, for 3 weeks, starting on day 15 post-immunization. The rats were sacrificed on day 36 post-immunization, and the soleus muscles were evaluated by light microscopy and transmission electron microscopy. Findings were compared with a non-treated EAE group. Electron microscopy analysis showed the presence of degenerated mitochondria, autophagic vacuoles, and altered myofibrils in non-treated EAE group. This correlates with the presence of acid phosphatase activity in muscle fibers and core-targetoid lesions with desmin immunohistochemistry. Most myonuclei in the EAE group showed apoptotic features. In contrast, EAE induced-TMS treated animals had less ultrastructural changes in the mitochondria and the myofibrils, together with less frequent apoptotic nuclear features. Peripheral desmin+ protrusions, as a marker of active satellite cells, were significantly increased in TMS-treated group. This correlates ultrastructurally with the presence of active features in satellite cells in the TMS group. In conclusion, the attenuation of ultrastructural alterations in muscle fibers and activation response of satellite cells caused by EAE indicated that skeletal muscle had a regenerative response to TMS.

Biological effects of sodium fluoride varnishes used in remineralisation of enamel: An in vitro study.

AIM: During the last three decades, fluoride varnishes have been recognised as effective strategies for caries prevention in the young-child population and have contributed to a decrease in its prevalence worldwide. The present study aimed to assess in vitro the level of cytotoxicity and genotoxicity in human primary pulp fibroblasts (DPFs) of two NaF varnishes. MATERIALS AND METHODS: Four experimental assays were carried out (MTS, Mitotracker® system [mitochondrial function and morphology], Live/Dead®, and Comet) to assess the morphology, viability, and genotoxicity of two NaF varnishes (Duraphat® and Clinpro White®, both at two different concentrations). The essays were conducted on cultured pulp fibroblasts, grouped in four experimental and two control groups. Collected data were analysed by one-way ANOVA followed by the post hoc Bonferroni test. RESULTS: Some morphological changes of DPFs could be detected after the NaFVs stimulation. Most DPFs incubated in Duraphat (22.6 mg/L) maintained their morphological characteristics, except for a small decrease in cell size and shorter cytoplasmic projections (filopodia); DPFs treated with Clinpro White Varnish (22.6 mg/L) presented a morphology and size similar to the control group. DPFs exposed to Duraphat (113 mg/L) exhibited significant morphological alterations with considerable cell size increases and DPFs treated with Clinpro White Varnish (113 mg/L) showed a slight cell size increase without noticeable morphological anomalies. The Duraphat (22.6 mg/L) and Clinpro White Varnish (22.6 mg/L) groups promoted 31% and 35% cell proliferation, respectively, whereas DPFs proliferation with Duraphat (113 mg/L) decreased up to 59%, and cell proliferation with Clinpro White Varnish (113 mg/L) was similar to that of control. CONCLUSION: All tested varnishes induced changes in the fibroblastic mitochondria. In general, Duraphat was less biocompatible and caused a change in the number of mitochondria compared to Clinpro White Varnish.

Clinical and molecular findings in a cohort of ANO5-related myopathy.

OBJECTIVE: ANO5-related myopathy is an important cause of limb-girdle muscular dystrophy (LGMD) and hyperCKemia. The main descriptions have emerged from European cohorts, and the burden of the disease worldwide is unclear. We provide a detailed characterization of a large Brazilian cohort of ANO5 patients. METHODS: A national cross-sectional study was conducted to describe clinical, histopathological, radiological, and molecular features of patients carrying recessive variants in ANO5. Correlation of clinical and genetic characteristics with different phenotypes was studied. RESULTS: Thirty-seven patients from 34 nonrelated families with recessive mutations of ANO5 were identified. The most common phenotype was LGMD, observed in 25 (67.5%) patients, followed by pseudometabolic presentation in 7 (18.9%) patients, isolated asymptomatic hyperCKemia in 4 (10.8%) patients, and distal myopathy in a single patient. Nine patients presented axial involvement, including one patient with isolated axial weakness. The most affected muscles according to MRI were the semimembranosus and gastrocnemius, but paraspinal and abdominal muscles, when studied, were involved in most patients. Fourteen variants in ANO5 were identified, and the c.191dupA was present in 19 (56%) families. Sex, years of disease, and the presence of loss-of-function variants were not associated with specific phenotypes. INTERPRETATION: We present the largest series of anoctaminopathy outside Europe. The most common European founder mutation c.191dupA was very frequent in our population. Gender, disease duration, and genotype did not determine the phenotype.

Increased Functional Connectivity After Listening to Favored Music in Adults With Alzheimer Dementia.

BACKGROUND: Personalized music programs have been proposed as an adjunct therapy for patients with Alzheimer disease related dementia, and multicenter trials have now demonstrated improvements in agitation, anxiety, and behavioral symptoms. Underlying neurophysiological mechanisms for these effects remain unclear. METHODS: We examined 17 individuals with a clinical diagnosis of Alzheimer disease related dementia using functional MRI following a training period in a personalized music listening program. RESULTS: We find that participants listening to preferred music show specific activation of the supplementary motor area, a region that has been associated with memory for familiar music that is typically spared in early Alzheimer disease. We also find widespread increases in functional connectivity in corticocortical and corticocerebellar networks following presentation of preferred musical stimuli, suggesting a transient effect on brain function. CONCLUSIONS: Findings support a mechanism whereby attentional network activation in the brain's salience network may lead to improvements in brain network synchronization.

Selectivity of Organic Products to Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae).

The selectivity of various entomopathogens and one insecticide (chlorpyrifos = positive control) to Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) was evaluated in the laboratory, using the protocol established by the Working Group on "Pesticides and Beneficial Organisms" of the IOBC. The evaluated parameters were parasitism (%), adult emergence (%), and product repellency to the parasitoid when sprayed on host eggs prior to parasitism (free-choice and no-choice tests). Most of the studied entomopathogens (Bacillus thuringiensis var. kurstaki, Bacillus thuringiensis var. aizawai, Beauveria bassiana, Metarhizium anisopliae, and Trichoderma harzianum) had no effects on biological parameters and were classified as harmless to T. pretiosum. Emergence of parasitoids (progeny viability) was reduced, but remained above 90%, when host eggs were sprayed with Baculovirus anticarsia prior to parasitism in the free-choice test, and B. anticarsia was therefore considered harmless. Chlorpyrifos (positive control) caused high adult parasitoid mortality in all bioassays. While T. pretiosum and the tested entomopathogens may be used simultaneously in integrated pest management programs, the use of chlorpyrifos should be avoided.

Meson-exchange currents and quasielastic antineutrino cross sections in the superscaling approximation.

We evaluate quasielastic double-differential antineutrino cross sections obtained in a phenomenological model based on the superscaling behavior of electron scattering data and estimate the contribution of the vector meson-exchange currents in the two-particle-two-hole sector. We show that the impact of meson-exchange currents for charge-changing antineutrino reactions is much larger than in the neutrino case.

[Impact of consumption of corn flour with low level enrichment in children of rural zones]. / Impacto del consumo de harina de maíz con un bajo nivel de enriquecimiento en niños de zonas rurales.

INTRODUCTION: Corn has been from the prehispanic era, the most important feeding plant in the Mexican population, particularly in the most important sectors and in marginal areas. In this setting, enriching the product as flour implies an increase in its nutritional quality, especially because corn is the basic food. OBJECTIVE: To assess the effect of the consumption of corn flour enriched with 3% soybean, vitamins, and minerals on the growth and development of infants and preschool children. MATERIAL AND METHODS: experimental study lasting 10 months. The experimental group (n=195) received enriched corn flour whereas the control group (n=200) received non-enriched flour. The indicators were: nutritional status, mental and psychomotor development, and blood hemoglobin levels. RESULTS: in the total sample, there were no differences between the experimental group and the control group. However, there were improvements in the weight-to-height and weight-to-age indexes in the children consuming enriched flour and in children older than one year, who were the babies of indigenous women living in marginal areas. CONCLUSIONS: enriched corn flour appears to be an alternative benefitting the children population with higher nutritional deficiencies. However, a longer intervention is necessary to obtain better results.

Culture and the anxiety disorders: recommendations for DSM-V.

BACKGROUND: The anxiety disorders specified in the fourth edition, text revision, of The Diagnostic and Statistical Manual (DSM-IV-TR) are identified universally in human societies, and also show substantial cultural particularities in prevalence and symptomatology. Possible explanations for the observed epidemiological variability include lack of measurement equivalence, true differences in prevalence, and limited validity or precision of diagnostic criteria. One central question is whether, through inadvertent "over-specification" of disorders, the post-DSM-III nosology has missed related but somewhat different presentations of the same disorder because they do not exactly fit specified criteria sets. This review canvases the mental health literature for evidence of cross-cultural limitations in DSM-IV-TR anxiety disorder criteria. METHODS: Searches were conducted of the mental health literature, particularly since 1994, regarding cultural or race/ethnicity-related factors that might limit the universal applicability of the diagnostic criteria for six anxiety disorders. RESULTS: Possible mismatches between the DSM criteria and the local phenomenology of the disorder in specific cultural contexts were found for three anxiety disorders in particular. These involve the unexpectedness and 10-minute crescendo criteria in Panic Disorder; the definition of social anxiety and social reference group in Social Anxiety Disorder; and the priority given to psychological symptoms of worry in Generalized Anxiety Disorder. Limited evidence was found throughout, particularly in terms of neurobiological markers, genetic risk factors, treatment response, and other DSM-V validators that could help clarify the cross-cultural applicability of criteria. CONCLUSIONS: On the basis of the available data, options and preliminary recommendations for DSM-V are put forth that should be further evaluated and tested.

Quasielastic charged-current neutrino-nucleus scattering.

We provide integrated cross sections for quasielastic charged-current neutrino-nucleus scattering. Results evaluated using the phenomenological scaling function extracted from the analysis of experimental (e, e') data are compared with those obtained within the framework of the relativistic impulse approximation. We show that very reasonable agreement is reached when a description of final-state interactions based on the relativistic mean field is included. This is consistent with previous studies of differential cross sections which are in accord with the universality property of the superscaling function.

Interleukina 18, ¿nuevo factor a tener en cuenta en la patogénesis de la enfermedad periodontal? / Interleukin 18. A new factor in the pathogenesis of the periodontal disease

La enfermedad periodontal es un proceso infeccioso crónico y de naturaleza inflamatoria, donde se produce la pérdida de los tejidos de sostén del diente. Existe un acuerdo general en que son las bacterias de la placa las responsables del inicio y mantenimiento de la enfermedad; pero se cree que será el tipo de respuesta inmune del individuo, la responsable del grado de destrucción periodontal que se desarrolle. Se piensa que una respuesta mediada por anticuerpos produciría una mayor destrucción debido a la hiperestimulación del sistema inmune, mientras que una respuesta celular sería más protectora con los tejidos periodontales. En este artículo proponemos que, la interleukina 18 (IL-18), citokina inductora de interferón gamma, favorecería el desarrollo de una respuesta inmune celular, permitiendo una eliminación bacteriana más eficaz, reduciendo así el daño que sufrirían los tejidos periodontales (AU)

Periodontal disease is an inflammatory, chronic and infectious process, where the tooth support tissues get lost. There is an agreement that bacteria are responsible for the beginning and support of the disease. It is believed that the type of individual immune response is responsible for the periodontal destruction degree. It is thought that an immune response regulated by antibodies would produce larger tissue destruction, due to the hyperstimulation of the immune system. While cellular immune response would be more protective with periodontal tissues. In this paper, we suggest that interleukin 18 (IL-18), as an interferon gamma inductor, would favor the cellular immune response development, allowing a more efficient elimination, reducing the periodontal tissue damage (AU)

Sistema de clasificación de patologías en Rehabilitación en pacientes ambulatorios / Disease classification systems in Rehabilitation for out-patients

Introducción. El objetivo de este trabajo fue elaborar un sistema de clasificación de pacientes en rehabilitación ambulatoria, común para Atención Primaria (AP) y Atención Especializada (AE). Métodos. La elaboración siguió dos etapas:1. Estudio descriptivo de las patologías atendidas a nivel ambulatorio durante el año 2002 en los Centros de Especialidades y un Centro Hospitalario y en las Unidades de Fisioterapia de AP del área sanitaria 1 de la Comunidad de Madrid. Se revisó una muestra aleatoria de 945 historias clínicas de un total de 47.204. 2. Revisión bibliográfica de publicaciones en MEDLINE de sistemas de clasificación de patologías en rehabilitación. Las patologías atendidas en AE se clasificaron en función del diagnóstico principal y en AP en función del motivo de derivación de la consulta del médico de familia a la Unidad de Fisioterapia. Se reagruparon en función de la prevalencia y se codificaron siguiendo los criterios de la Clasificación Internacional de Enfermedades, 9.ª revisión Modificación Clínica (CIE-9-MC) y criterios de la Clasificación Internacional de Atención Primaria (CIAP). Se constituyó un grupo de trabajo con profesionales que participan en el proceso de rehabilitación ambulatoria en el área sanitaria 1 de la Comunidad de Madrid, para consensuar el sistema de clasificación de patologías. Resultados. Elaboración de un sistema de clasificación de patologías en pacientes ambulatorios en rehabilitación, común para AP y AE. Conclusiones. Establecer un único sistema de clasificación de pacientes en el proceso de rehabilitación ambulatoria permite describir el tipo de pacientes que demanda atención y comparar las patologías atendidas en los diferentes centros de los dos niveles asistenciales

Introduction. The objective of the study has been to develop a classification system of patients for use in out-patient rehabilitation for Primary Care (PC) and Specialized Care (SC). Methods. It was developed in two phases:1. Descriptive study of diseases attended in out-patient care during the year 2002 in the speciality centers, hospital center and physiotherapy units of health district 1 primary care of the Community of Madrid. A random sample of 945 clinical records out of a total of 47204 were reviewed. 2. Review of the available literature in MEDLINE in order to find patient classification systems in rehabilitation and to analyze its possible application in our setting. The classification was performed using the principal diagnosis of the patient according to International Classification of Diseases 9th revision Clinical Modification (ICD-9-MC) for patients treated in speciality centers and hospitals centers or International Classification of Primary Care (ICPC) for patients treated in primary care. Secondly, the diseases were grouped based on the prevalence. A workgroup reviewed the patients classification system. The workgroup was constituted by health professionals involved in the process of rehabilitation in out-patient care in health district 1 of the Community of Madrid. Results. Development of a patients classification system in out-patient rehabilitation, common for PC and SC. Conclusions. To establish an unique patients classification system in the process of out-patient rehabilitation makes it possible to describe the type of patients that demands health services and to compare the diseases attended in different centers

Superscaling in charged current neutrino quasielastic scattering in the relativistic impulse approximation.

Superscaling of the quasielastic cross section in charged-current neutrino-nucleus reactions at energies of a few GeV is investigated within the framework of the relativistic impulse approximation. Several approaches are used to describe final-state interactions and comparisons are made with the plane-wave approximation. Superscaling is very successful in all cases. The scaling function obtained using a relativistic mean field for the final states shows an asymmetric shape with a long tail extending towards positive values of the scaling variable, in excellent agreement with the behavior presented by the experimental scaling function.

Interventions for treating posterior cruciate ligament injuries of the knee in adults.

BACKGROUND: Injuries of the posterior cruciate ligament (PCL) of the knee frequently occur in automobile accidents and sports injuries, although they are less frequent overall than injuries of the anterior cruciate ligament (ACL). Some patients show significant symptoms and subsequent articular deterioration, while others are essentially asymptomatic, maintaining habitual function. Management of PCL injuries remains controversial and prognosis can vary widely. Interventions extend from non-operative (conservative) procedures to reconstruction of the PCL, in the hope that the surgical procedure may have a positive effect in the reduction/prevention of future osteoarthritic changes in the knee. OBJECTIVES: To determine the effectiveness and safety of surgical and conservative interventions for PCL injuries in adults. SEARCH STRATEGY: We searched the Cochrane Musculoskeletal Injuries Group Specialised Register (April 2004), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2004), MEDLINE via PubMed (1966 to April 2004), EMBASE (1966 to April 2004), CINAHL (1982 to April 2004), LILACS (1982 to April 2004), SportsDiscus (1975 to April 2004), and reference lists of articles. SELECTION CRITERIA: Randomized or quasi-randomized clinical trials comparing various methods of operative and conservative interventions, and comparisons with each other for the treatment of PCL injuries. DATA COLLECTION AND ANALYSIS: References found with the search strategy were evaluated independently by two review authors. MAIN RESULTS: No randomized or quasi-randomized controlled studies meeting the selection criteria were identified. AUTHORS' CONCLUSIONS: Future research should include randomized controlled trials of acute isolated PCL injuries, or PCL injuries when combined with other ligament injuries of the knee, treated operatively and conservatively. Adequate numbers of patients and an objective methodology for patient evaluation must be used in future studies of these interventions to determine the long-term results.

Visual prognosis in immunocompetent patients with herpes zoster ophthalmicus.

PURPOSE: To determine the normal spectrum of ocular complications and associated visual outcome in patients with herpes zoster ophthalmicus. METHODS: This prospective observational cohort study included 73 immunocompetent adults with herpes zoster ophthalmicus, referred by their general practitioners within 7 days of skin rash onset. The follow-up period was 6 months. All patients received a 7-14-day course of systemic aciclovir treatment combined with longterm application of a lubricating ophthalmic ointment as long as the corneal epithelium was affected. Topical corticosteroids were strictly avoided in the acute phase of ocular disease. Acquired visual loss scores at 1, 2 and 6 months were based on best corrected visual acuity (BCVA) level and evaluation of the ophthalmological history and findings. RESULTS: Ophthalmic herpes zoster led to a variety of transient inflammatory reactions within the anterior eye segment of the involved side in 46 patients (63%), but did not seriously compromise their ultimate visual outcome. Mild to moderate visual loss, with corrected VA between 0.3 and 0.8, was found in 17 patients at 1 month (23%), in 10 patients at 2 months (14%) and in seven patients at 6 months follow-up (10%). None of the patients developed visual loss with a corrected VA of less than 0.3. CONCLUSION: Functional vision was retained in all ophthalmic zoster patients referred to the ophthalmologist in the acute phase of the disease by vigorous antiviral treatment and adequate prevention of corneal exposure.

Experimental model of bladder instability in rabbits

OBJECTIVE: Propose a new experimental model of bladder instability in rabbits after partial bladder obstruction. MATERIALS AND METHODS: Thirty North Folk male rabbits, weighting 1,700 to 2,820 g (mean: 2,162 g) were studied. The animals were distributed in 2 experimental groups, formed by 15 rabbits each: Group 1 - clinical control. In this group there was no surgical intervention; Group 2 - bladder outlet obstruction. In this group, after anesthetizing the animal, urethral cannulation with Foley catheter 10F was performed and then an adjustable plastic bracelet was passed around the bladder neck. It was then adjusted in order to not constrict the urethra. The following parameters were studied in M1 - pre-operative period; M2 - 4 weeks post-operatively moments: 1)- urine culture; 2)- cystometric study; 3)- serum creatinine and BUN. RESULTS: Bladder weight was 2.5 times larger in the group with obstruction than in the control group. Cystometric evaluation showed a significant increase in maximal vesical volume in the final moment at Group G2. However, there was no statistically significant difference among the groups studied. There was no statistically significant difference between maximal detrusor pressure and vesical compliance in the different moments or in the studied groups. There was an absence of uninhibited detrusor contractions in all the animals in group 1, and involuntary contractions were detected in 93 percent of group 2 animals. There was no significant variation in BUN and serum creatinine either among the groups or in the same group. CONCLUSIONS: We observed in the group with obstruction a bladder weight 2.5 higher than normal bladders. We detected involuntary contractions in 93 percent of the animals in group 2, establishing this experimental model as appropriate to secondary bladder instability and partial bladder outlet obstruction

Experimental model of bladder instability in rabbits.

OBJECTIVE: Propose a new experimental model of bladder instability in rabbits after partial bladder obstruction. MATERIALS AND METHODS: Thirty North Folk male rabbits, weighting 1,700 to 2,820 g (mean: 2,162 g) were studied. The animals were distributed in 2 experimental groups, formed by 15 rabbits each: Group 1 - clinical control. In this group there was no surgical intervention; Group 2 - bladder outlet obstruction. In this group, after anesthetizing the animal, urethral cannulation with Foley catheter 10F was performed and then an adjustable plastic bracelet was passed around the bladder neck. It was then adjusted in order to not constrict the urethra. The following parameters were studied in M1 - pre-operative period; M2 - 4 weeks post-operatively moments: 1)- urine culture; 2)- cystometric study; 3)- serum creatinine and BUN. RESULTS: Bladder weight was 2.5 times larger in the group with obstruction than in the control group. Cystometric evaluation showed a significant increase in maximal vesical volume in the final moment at Group G2. However, there was no statistically significant difference among the groups studied. There was no statistically significant difference between maximal detrusor pressure and vesical compliance in the different moments or in the studied groups. There was an absence of uninhibited detrusor contractions in all the animals in group 1, and involuntary contractions were detected in 93% of group 2 animals. There was no significant variation in BUN and serum creatinine either among the groups or in the same group. CONCLUSIONS: We observed in the group with obstruction a bladder weight 2.5 higher than normal bladders. We detected involuntary contractions in 93% of the animals in group 2, establishing this experimental model as appropriate to secondary bladder instability and partial bladder outlet obstruction.

Histocompatibility and corneal transplantation.

BACKGROUND: HLA typing and matching have been poorly implemented in corneal transplantation, mainly because of inconclusive or contradictory analytical results. Consequently, we studied the immune response of corneal transplant recipients to HLA histoincompatibilities in a large homogeneous study. METHODS: All corneal transplantations were performed by a single surgeon in a single center between 1976 and 1996. Population genetic and other statistical analyses were performed. Simulation studies assessed the effects of HLA-DR mistypings on analytical results. RESULTS: Mono- and multivariate analyses identified retransplantation, degree of vascularization, HLA-AB and -DR match grades, endothelial cell count, graft size, recipient gender, storage method and panel-reactive antibodies as significantly influencing the survival of corneal transplants. Simulation studies showed that the beneficial effect of HLA-DR matching is abrogated by HLA-DR mistypings. CONCLUSIONS: Corneal transplant recipients have a normal immune response to HLA incompatibilities. Demonstration of that fact requires accurate HLA typings.