Return to work after COVID-19 infection - A Danish nationwide registry study.

OBJECTIVES: This study aimed to explore return to work after COVID-19 and how disease severity affects this. STUDY DESIGN: This is a Nationwide Danish registry-based cohort study using a retrospective follow-up design. METHODS: Patients with a first-time positive SARS-CoV-2 polymerase chain reaction test between 1 January 2020 and 30 May 2020, including 18-64 years old, 30-day survivors, and available to the workforce at the time of the first positive test were included. Admission types (i.e. no admission, admission to non-intensive care unit [ICU] department and admission to ICU) and return to work was investigated using Cox regression standardised to the age, sex, comorbidity and education-level distribution of all included subjects with estimates at 3 months from positive test displayed. RESULTS: Among the 7466 patients included in the study, 81.9% (6119/7466) and 98.4% (7344/7466) returned to work within 4 weeks and 6 months, respectively, with 1.5% (109/7466) not returning. Of the patients admitted, 72.1% (627/870) and 92.6% (805/870) returned 1 month and 6 months after admission to the hospital, with 6.6% (58/870) not returning within 6 months. Of patients admitted to the ICU, 36% (9/25) did not return within 6 months. Patients with an admission had a lower chance of return to work 3 months from positive test (relative risk [RR] 0.95, 95% confidence interval [CI] 0.94-0.96), with the lowest chance in patients admitted to an ICU department (RR 0.54, 95% CI 0.35-0.72). Female sex, older age, and comorbidity were associated with a lower chance of returning to work. CONCLUSION: Hospitalised patients with COVID-19 infection have a lower chance of returning to work with potential implications for postinfection follow-up and rehabilitation.

Increased long-term risk of heart failure and other adverse cardiac outcomes in dermatomyositis and polymyositis: Insights from a nationwide cohort.

BACKGROUND: Mounting evidence suggests that dermatomyositis/polymyositis (DM/PM) are associated with increased risk of atherosclerotic events and venous thromboembolism. However, data on the association between DM/PM and other cardiac outcomes, especially heart failure (HF), are scarce. OBJECTIVES: To examine the long-term risk and prognosis associated with adverse cardiac outcomes in patients with DM/PM. METHODS: Using Danish administrative registries, we included all patients ≥18 years with newly diagnosed DM/PM (1996-2018). Risks of incident outcomes were compared with non-DM/PM controls from the background population (matched 1:4 by age, sex, and comorbidity). In a secondary analysis, we compared mortality following HF diagnosis between DM/PM patients with HF and non-DM/PM patients with HF (matched 1:4 by age and sex). RESULTS: The study population included 936 DM/PM patients (median age 58.5 years, 59.0% women) and 3744 matched non-DM/PM controls. The median follow-up was 6.9 years. Absolute 10-year risks of incident outcomes for DM/PM patients vs matched controls were as follows: HF, 6.98% (CI, 5.16-9.16%) vs 4.58% (3.79-5.47%) (P = 0.002); atrial fibrillation, 10.17% (7.94-12.71%) vs 7.07% (6.09-8.15%) (P = 0.005); the composite of ICD implantation/ventricular arrhythmias/cardiac arrest, 1.99% (1.12-3.27%) vs 0.64% (0.40-0.98%) (P = 0.02); and all-cause mortality, 35.42% (31.64-39.21%) vs 16.57% (15.10-18.10%) (P < 0.0001). DM/PM with subsequent HF was associated with higher mortality compared with HF without DM/PM (adjusted hazard ratio 1.58 [CI, 1.01-2.47]). CONCLUSION: Patients with DM/PM had a higher associated risk of HF and other adverse cardiac outcomes compared with matched controls. Among patients developing HF, a history of DM/PM was associated with higher mortality.

Preheart failure comorbidities and impact on prognosis in heart failure patients: a nationwide study.

BACKGROUND: Data regarding the impact of preheart failure (HF) comorbidities on the prognosis of HF are scarce, especially in the younger HF patients. OBJECTIVES: To investigate pre-existing comorbidities in HF patients versus matched controls and to assess their impact on mortality. METHODS: We included all first-time in-hospital and outpatient diagnoses of HF from 1995 to 2017, and comorbidities antedating the HF-diagnosis in the Danish nationwide registries. HF patients were matched with up to five controls. One-year all-cause mortality rates and population attributable risk (PAR) were estimated for three separate age groups (≤50, 51-74 and >74 years). RESULTS: Totally 280 002 patients with HF and 1 166 773 controls were included. Cardiovascular comorbidities, for example, cerebrovascular disease and ischaemic heart disease were more frequent in the oldest (17.9% and 29.7% in HF vs. 9.8% and 10.7% in controls) compared to the youngest age group (3.9% and 15.2% in HF vs. 0.7% and 0.9% in controls). Amongst patients with HF, 1-year mortality rates (per 100 person-years) were highest amongst those with >1 noncardiovascular comorbidity: ≤50 years (10.4; 9.64-11.3), 51-74 years (23.3; 22.9-23.7), >74 years (58.5; 57.9-59.0); hazard ratios 245.18 (141.45-424.76), 45.85 (42.77-49.15) and 24.5 (23.64-25.68) for those ≤50, 51-74 and >74 years, respectively. For HF patients ≤50 years, PAR was greatest for hypertension (17.8%), cancer (14.1%) and alcohol abuse (8.5%). For those aged >74 years, PAR was greatest for hypertension (23.6%), cerebrovascular disease (6.2%) and cancer (7.2%). CONCLUSIONS: Heart failure patients had a higher burden of pre-existing comorbidities, compared to controls, which adversely impacted prognosis, especially in the young.

Evolution of sociality in spiders leads to depleted genomic diversity at both population and species levels.

Across several animal taxa, the evolution of sociality involves a suite of characteristics, a "social syndrome," that includes cooperative breeding, reproductive skew, primary female-biased sex ratio, and the transition from outcrossing to inbreeding mating system, factors that are expected to reduce effective population size (Ne). This social syndrome may be favoured by short-term benefits but come with long-term costs, because the reduction in Ne amplifies loss of genetic diversity by genetic drift, ultimately restricting the potential of populations to respond to environmental change. To investigate the consequences of this social life form on genetic diversity, we used a comparative RAD-sequencing approach to estimate genomewide diversity in spider species that differ in level of sociality, reproductive skew and mating system. We analysed multiple populations of three independent sister-species pairs of social inbreeding and subsocial outcrossing Stegodyphus spiders, and a subsocial outgroup. Heterozygosity and within-population diversity were sixfold to 10-fold lower in social compared to subsocial species, and demographic modelling revealed a tenfold reduction in Ne of social populations. Species-wide genetic diversity depends on population divergence and the viability of genetic lineages. Population genomic patterns were consistent with high lineage turnover, which homogenizes the genetic structure that builds up between inbreeding populations, ultimately depleting genetic diversity at the species level. Indeed, species-wide genetic diversity of social species was 5-8 times lower than that of subsocial species. The repeated evolution of species with this social syndrome is associated with severe loss of genomewide diversity, likely to limit their evolutionary potential.

Prevalence of serum anti-neuronal autoantibodies in patients admitted to acute psychiatric care.

BACKGROUND: Autoimmune encephalitis associated with anti-neuronal antibodies may be challenging to distinguish from primary psychiatric disorders. The significance of anti-neuronal antibodies in psychiatric patients without clear evidence of autoimmune encephalitis is unknown. We investigated the serum prevalence of six anti-neuronal autoantibodies in a cohort of unselected patients admitted to acute psychiatric care. METHOD: Serum was drawn from 925 patients admitted to acute psychiatric in-patient care. Psychiatric diagnoses were set according to International Classification of Diseases (ICD)-10 criteria. Antibody analysis was performed with an indirect immunofluorescence test for N-methyl d-aspartate receptor (NMDAR) antibodies and five other anti-neuronal autoantibodies of the immunoglobulin (Ig) classes IgA, IgG and IgM isotype. RESULTS: Anti-neuronal autoantibodies were found in 11.6% of patients: NMDAR antibodies in 7.6%, contactin-associated protein-like 2 (CASPR2) antibodies in 2.5%, glutamic acid decarboxylase-65 (GAD65) antibodies in 1.9%, and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antibodies in 0.1%. Leucine-rich glioma-inactivated protein-1 (LGI1) and γ-aminobutyric acid B (GABAB) receptor antibodies were not detected. NMDAR antibodies of class IgG were present in five patients only (0.5%). NMDAR antibodies of all Ig classes were equally prevalent in patients with and without psychosis. There were no significant differences in antibody prevalence in the different diagnostic categories, except for a higher odds ratio of being NMDAR antibody positive for patients without a specific psychiatric diagnosis. CONCLUSIONS: NMDAR IgG autoantibodies, which are known to be strongly associated with anti-NMDAR encephalitis, were rarely found. CASPR2 and GAD65 antibodies were more frequently encountered in the present study than previously reported. Further research on the clinical significance of anti-neuronal autoantibodies in patients with acute psychiatric symptoms is needed.

Inbreeding depression across a nutritional stress continuum.

Many natural populations experience inbreeding and genetic drift as a consequence of nonrandom mating or low population size. Furthermore, they face environmental challenges that may interact synergistically with deleterious consequences of increased homozygosity and further decrease fitness. Most studies on inbreeding-environment (I-E) interactions use one or two stress levels, whereby the resolution of the possible stress and inbreeding depression interaction is low. Here we produced Drosophila melanogaster replicate populations, maintained at three different population sizes (10, 50 and a control size of 500) for 25 generations. A nutritional stress gradient was imposed on the replicate populations by exposing them to 11 different concentrations of yeast in the developmental medium. We assessed the consequences of nutritional stress by scoring egg-to-adult viability and body mass of emerged flies. We found: (1) unequivocal evidence for I-E interactions in egg-to-adult viability and to a lesser extent in dry body mass, with inbreeding depression being more severe under higher levels of nutritional stress; (2) a steeper increase in inbreeding depression for replicate populations of size 10 with increasing nutritional stress than for replicate populations of size 50; (3) a nonlinear norm of reaction between inbreeding depression and nutritional stress; and (4) a faster increase in number of lethal equivalents in replicate populations of size 10 compared with replicate populations of size 50 with increasing nutritional stress levels. Our data provide novel and strong evidence that deleterious fitness consequences of I-E interactions are more pronounced at higher nutritional stress and at higher inbreeding levels.

Association between left ventricular global longitudinal strain and natriuretic peptides in outpatients with chronic systolic heart failure.

BACKGROUND: Both impaired left ventricular (LV) global longitudinal strain (GLS) and increased plasma concentrations of natriuretic peptides(NP) are associated with a poor outcome in heart failure (HF). Increased levels of NP reflect increased wall stress of the LV. However, little is known about the relationship between LV GLS and NP. This aim of this study was to evaluate the relationship between the echocardiographic measure LV GLS and plasma levels of NP. METHODS: We prospectively included 149 patients with verified systolic HF at the baseline visit in an outpatient HF clinic. LV GLS was assessed by two dimension speckle tracking and plasma concentrations of N-terminal-pro-brain-natriuretic-peptide (NT-proBNP) and pro-atrial-natriuretic-peptide (proANP) were analysed. RESULTS: The patients had a median age of 70 years, 28.2 % were females, 26.5 % were in functional class III-IV, median left ventricular ejection fraction (LVEF) was 33 % and median LV GLS was -11 %. LV GLS was associated with increased plasma concentrations of NT-proBNP and proANP in multivariate logistic regression (NT-proBNP: Odds RatioGLS: 7.25, 95 %-CI: 2.48-21.1, P < 0.001 and proANP: Odds RatioGLS: 3.26, 95-%-CI: 1.28-8.30, P = 0.013) and linear regression (NT-proBNP: ßGLS: 1.19, 95 %-CI: 0.62-1.76, P < 0.001 and proANP: ßGLS: 0.42, 95-%-CI: 0.11-0.72, P = 0.007) models after adjustment for traditional confounders (age, gender, body-mass-index, atrial fibrillation, renal function) and left atrial volume index. CONCLUSION: Impaired LV GLS is associated with increased plasma concentrations of NP and our data suggest that left ventricular myocardial mechanics estimated by LV GLS reflects myocardial wall stress in chronic systolic HF.

A Drosophila laboratory evolution experiment points to low evolutionary potential under increased temperatures likely to be experienced in the future.

The ability to respond evolutionarily to increasing temperatures is important for survival of ectotherms in a changing climate. Recent studies suggest that upper thermal limits may be evolutionary constrained. We address this hypothesis in a laboratory evolution experiment, encompassing ecologically relevant thermal regimes. To examine the potential for species to respond to climate change, we exposed replicate populations of Drosophila melanogaster to increasing temperatures (0.3 °C every generation) for 20 generations, whereas corresponding replicate control populations were held at benign thermal conditions throughout the experiment. We hypothesized that replicate populations exposed to increasing temperatures would show increased resistance to warm and dry environments compared with replicate control populations. Contrasting replicate populations held at the two thermal regimes showed (i) an increase in desiccation resistance and a decline in heat knock-down resistance in replicate populations exposed to increasing temperatures, (ii) similar egg-to-adult viability and fecundity in replicate populations from the two thermal regimes, when assessed at high stressful temperatures and (iii) no difference in nucleotide diversity between thermal regimes. The limited scope for adaptive evolutionary responses shown in this study highlights the challenges faced by ectotherms under climate change.

Incidence of acute myocardial infarction-related cardiogenic shock during corona virus disease 19 (COVID-19) pandemic.

AIMS: The hospitalization of patients with MI has decreased during global lockdown due to the COVID-19 pandemic. Whether this decrease is associated with more severe MI, e.g. MI-CS, is unknown. We aimed to examine the association of Corona virus disease (COVID-19) pandemic and incidence of acute myocardial infarction with cardiogenic shock (MI-CS). METHODS: On March 11, 2020, the Danish government announced national lock-down. Using Danish nationwide registries, we identified patients hospitalized with MI-CS. Incidence rates (IR) and incidence rate ratios (IRR) were used to compare MI-CS before and after March 11 in 2015-2019 and in 2020. RESULTS: We identified 11,769 patients with MI of whom 696 (5.9%) had cardiogenic shock in 2015-2019. In 2020, 2132 MI patients were identified of whom 119 had cardiogenic shock (5.6%). The IR per 100,000 person years before March 11 in 2015-2019 was 9.2 (95% CI: 8.3-10.2) and after 8.9 (95% CI: 8.0-9.9). In 2020, the IR was 7.5 (95% CI: 5.8-9.7) before March 11 and 7.7 (95% CI: 6.0-9.9) after. The IRRs comparing the 2020-period with the 2015-2019 period before and after March 11 (lockdown) were 0.81 (95% CI: 0.59-1.12) and 0.87 (95% CI: 0.57-1.32), respectively. The IRR comparing the 2020-period during and before lockdown was 1.02 (95% CI: 0.74-1.41). No difference in 7-day mortality or in-hospital management was observed between study periods. CONCLUSION: We could not identify a significant association of the national lockdown on the incidence of MI-CS, along with similar in-hospital management and mortality in patients with MI-CS.

Low N-terminal pro-brain natriuretic peptide levels are associated with non-alcoholic fatty liver disease in patients with type 2 diabetes.

AIM: Natriuretic peptides (NPs) have emerged as important regulators of lipid metabolism. Reduced levels of NPs are reported in obesity and in patients with type 2 diabetes (T2D). This NP deficiency may affect their ectopic fat distribution and lead to high risk of non-alcoholic fatty liver disease (NAFLD). METHODS: In this cross-sectional study, the association between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and liver fat content was quantified using 1H-magnetic resonance spectroscopy in 120 patients with T2D. RESULTS: NAFLD (defined as liver fat content ≥ 5.6%) was found in 57 (48%) of the T2D patients, who also had significantly lower NT-proBNP (P = 0.002) levels compared with patients without NAFLD, but did not differ as regards the presence of cardiovascular disease (CVD) or in kidney function. After adjusting for potential confounders (age, gender, HbA1c, BMI, HOMA2-IR, CVD, eGFR), the odds ratio for the presence of NAFLD was increased by 2.9 (P = 0.048) for NT-proBNP levels < 45 ng/L. In a multivariable linear regression model, the relationship with NT-proBNP was further analyzed as a continuous variable, and was independently and inversely associated with increasing liver fat content after full adjustment (P = 0.031). CONCLUSION: Reduced plasma NT-proBNP levels are independently associated with high liver fat content in patients with T2D. The present study suggests that NP deficiency may play a role in the development of NAFLD in T2D.

A prospective three-year follow-up study on the clinical significance of anti-neuronal antibodies in acute psychiatric disorders.

The clinical significance of anti-neuronal antibodies for psychiatric disorders is controversial. We investigated if a positive anti-neuronal antibody status at admission to acute psychiatric inpatient care was associated with a more severe neuropsychiatric phenotype and more frequent abnormalities during clinical work-up three years later. Patients admitted to acute psychiatric inpatient care who tested positive for N-methyl-D-aspartate receptor (NMDAR), contactin-associated protein 2 (CASPR2) and/or glutamic acid decarboxylase 65 (GAD65) antibodies (n = 24) were age - and sex matched with antibody-negative patients (1:2) from the same cohort (n = 48). All patients were invited to follow-up including psychometric testing (e.g. Symptom Checklist-90-Revised), serum and cerebrospinal fluid (CSF) sampling, EEG and 3 T brain MRI. Twelve antibody-positive (ab+) and 26 antibody-negative (ab-) patients consented to follow-up. Ab+ patients had more severe symptoms of depression (p = 0.03), psychoticism (p = 0.04) and agitation (p = 0.001) compared to ab- patients. There were no differences in CSF analysis (n = 6 ab+/12 ab-), EEG (n = 7 ab+/19 ab-) or brain MRI (n = 7 ab+/17 ab-) between the groups. In conclusion, anti-neuronal ab+ status during index admission was associated with more severe symptoms of depression, psychoticism and agitation at three-year follow-up. This supports the hypothesis that anti-neuronal antibodies may be of clinical significance in a subgroup of psychiatric patients.

Mendelian analysis of a metastasis-prone substrain of BALB/c nude mice using a subcutaneously inoculated human tumour.

Most nude mice do not allow the formation of metastases after heterotransplantation of human malignant tumours. Here we describe a substrain of BALB/c nude mice (BALB/c/AnNCr) that reproducibly allows some human cancers to metastasize. By Mendelian analysis of hybrids between this substrain and C57BL/6J +/+ mice we found that the ability to allow a human tumour (MDA-MB-435 BAG) to express its metastatic phenotype is determined by a recessively inheritable trait in the mouse host. We are presently working to identify the genetics responsible for development of metastases. The study also includes immunohistochemical and electron microscopic analysis of the test tumour, originally assumed to be a human mammary carcinoma, but shown to possess characteristics of a malignant melanoma (1). The ultimate aim of our ongoing study is to establish a substrain of nude mice that will allow metastasis in all recipients.

Forty years of lithium treatment.

This review is based on a lecture in which I was requested to present my personal experiences and views. Since its introduction into psychiatry more than 40 years ago, lithium treatment has in most countries gained wide acceptance in the prophylaxis of unipolar and bipolar affective disorders. At one time it was feared that lithium treatment might lead to a decrease in the glomerular filtration rate, but systematically collected data indicate that even long-term treatment does not induce renal insufficiency. During treatment, regular laboratory monitoring of serum lithium and creatinine concentrations is recommended. Recent studies suggest that long-term lithium treatment does not raise the mortality of manic-depressive patients and indeed may have a mortality-lowering and antisuicidal effect. Despite the availability of alternative therapies, lithium remains the treatment of choice for the prophylaxis of recurrent manic-depressive illness.

The lithium librarian. An international index.

Lithium salts are being widely used for treatment and prophylaxis of bipolar affective disorder (manic-depressive psychosis) and are under investigation in more than 30 other illnesses. The relevant literature has grown from 43 articles published between 1949 and 1964 to nearly 4,000 today. A computer-based lithium librarian program has been developed that provides an up-to-date registry of all lithium references, rapid search capability, constant availability, and easy transferability to identical computer systems located on three continents. References provided by the system are more complete, more rapidly available, and less costly than references obtained from other bibliographic services. This specific response to the rapidly expanding lithium literature provides a model for comprehensive aquisition and searching of other specialized subjects areas needed by clinicians and researchers.

Lithium prophylaxis: myths and realities.

The author examines some widely held views about prophylactic lithium treatment. When seen in relation to the factual evidence concerning lithium, these views require revision because they are wrong or not valid for treatment carried out according to present-day guidelines.

In vitro and in vivo inhibition by lithium of enkephalin binding to opiate receptors in rat brain.

The in vitro and in vivo effects of lithium ions on opiate receptor binding were studied in the cerebral cortex, the hippocampus and the basal ganglia of the rat. In vitro, lithium ions inhibited enkephalin binding to opiate receptors through a reduction in the number of binding sites, whereas the affinity was unchanged or only slightly decreased. In vivo, long term ingestion of lithium (3 weeks), during which the rats were maintained at a serum lithium level of approximately 1 mM, also inhibited enkephalin binding to rat neuronal membranes (P2-fractions) through a reduction of the number of opiate receptor binding sites, whereas the affinity was unchanged. No lithium could be detected in the suspension of neuronal membranes from the lithium-treated rats, and no difference in the concentration of endogenous opioid peptides was found between control rats and lithium-treated rats. The opiate receptors from control rats and lithium-treated rats did no display any difference in lithium sensitivity. This data suggest that administration of lithium to rats in small doses reduces opiate receptor binding of enkephalin.

Opioid receptors in the brain of the rat following chronic treatment with desipramine and electroconvulsive shock.

The effect of chronic administration of electroconvulsive shock and the antidepressant drug desipramine on binding to opioid receptors was studied in the cerebral cortex, the basal ganglia and the hippocampus of the forebrain of the rat. In vitro, desipramine inhibited the binding of enkephalinamide to opioid receptors through a reduction in the number of binding sites, whereas the affinity was unchanged or only slightly decreased. In vivo desipramine, injected daily (10 mg/kg) for three weeks, did not change the number of opioid binding sites in the forebrain of the rat. Chronic electroconvulsive shock, given twice a week for three weeks, had no effect on the number of opioid binding sites in the forebrain of the rat. The data do not support the hypothesis of shared effects of lithium, tricyclic antidepressants and electroconvulsive shock on the opioid peptide-opioid receptor systems.

Association and linkage studies of CRH and PENK genes in bipolar disorder: a collaborative IGSLI study.

Corticotropin-releasing hormone (CRH) and proenkephalin (PENK) are hypothalamic peptides involved in the stress response and hypothalamic-pituitary axis regulation. Previous research has implicated these peptides in the pathogenesis of affective disorders. In this study we investigated two polymorphisms located in the genes that code for CRH and PENK by means of association and linkage analyses. A total of 138 bipolar patients and 108 controls were included in the association study. In addition, 24 families were available for linkage analysis, including six families of probands with documented periodic positivity of dexamethasone suppression tests (DST) during remission. We found no association of bipolar disorder with either gene. Similarly, we did not find any evidence of linkage (P = 0.56 for CRH and 0.52 for PENK) in the entire sample or in the subsample of families of DST positive probands. In conclusion, our study does not support the hypothesis that genes coding for CRH or PENK contribute to the genetic susceptibility to bipolar disorder. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:178-181, 2000.

Cytotoxicity towards neonatal versus adult BB rat pancreatic islet cells.

Cell-mediated autoimmunity is believed to influence the development of diabetes in BB rats. It has been suggested that the autoimmune destruction is due to lack of tolerance induction in early neonatal life caused by delayed maturation of the pancreatic beta cells. The present experiment has been initiated to investigate if there is any difference in in vitro cytotoxicity, and therefore antigenicity, to islet cells from neonatal, young and adult diabetes prone BB rats, and to establish the possible developmental difference in these rats compared to non diabetes prone Wistar Furth rats. Islets from rats of different ages were isolated, dispersed and 51C-labeled. In vitro cytotoxicity mediated by mononuclear spleen cells from newly diabetic BB rats was measured by counting gamma-ray emission from the culture supernatant after 16 h coincubation. We found that full adult-like islet cell maturation in BB rats--as evidenced by sensitivity to cytotoxicity--is not seen before the age of 8 to 21 days after birth. In contrast adult-like cytotoxicity to neonatal islets cells from Wistar Furth rats is seen already at the age of 8 days. Thus delayed islet cell maturation is a fact observed in BB rats.

Mononuclear cytotoxicity and proliferation towards glucose stimulated rodent pancreatic islet cells.

Diabetes is due to an autoimmune cellular immunologic destruction of the pancreatic beta cells. By the use of a chromium release assay and a proliferation assay we have investigated the possible role of beta cell activity for this destruction. Results show that in vitro glucose stimulated pancreatic islet cells are subjects to a slight but significantly higher cellular immunologic destruction by mononuclear spleen cells than unstimulated islet cells. The functional dependency of the islet cell destruction must be a product of both a mononuclear cell dysfunction and a specific islet cell pattern. This is due to the fact that all combinations of mononuclear cells and islet cells from diabetes prone BB rats and non-diabetes prone WF rats tested against each other, results in functional dependent cytotoxicity, except for the assay in which both effector cells and target cells are of WF rat origin. Additional observations indicate, that the diabetes prone BB rat mononuclear cells need previous in vivo activation as only cells from diabetic individuals, and not normoglycemic ones, display the reaction in question. Functional dependent cytotoxicity is validated in an other IDDM animal model--the NOD mouse. NOD mononuclear cells towards the murine MIN-6 beta cell line results in increased cellular cytotoxicity when the latter is glucose stimulated. Also the proliferative response of BB rat mononuclear cells to whole islets tend to show function dependency.