Temporal dynamics of depressive symptoms and cognitive decline in the oldest old: dynamic time warp analysis of the Leiden 85-plus study.

BACKGROUND: The prevalence of depressive symptoms and cognitive decline increases with age. We investigated their temporal dynamics in individuals aged 85 and older across a 5-year follow-up period. METHODS: Participants were selected from the Leiden 85-plus study and were eligible if at least three follow-up measurements were available (325 of 599 participants). Depressive symptoms were assessed at baseline and at yearly assessments during a follow-up period of up to 5 years, using the 15-item Geriatric Depression Scale (GDS-15). Cognitive decline was measured through various tests, including the Mini Mental State Exam, Stroop test, Letter Digit Coding test and immediate and delayed recall. A novel method, dynamic time warping analysis, was employed to model their temporal dynamics within individuals, in undirected and directed time-lag analyses, to ascertain whether depressive symptoms precede cognitive decline in group-level aggregated results or vice versa. RESULTS: The 325 participants were all 85 years of age at baseline; 68% were female, and 45% received intermediate to higher education. Depressive symptoms and cognitive functioning significantly covaried in time, and directed analyses showed that depressive symptoms preceded most of the constituents of cognitive impairment in the oldest old. Of the GDS-15 symptoms, those with the strongest outstrength, indicating changes in these symptoms preceded subsequent changes in other symptoms, were worthlessness, hopelessness, low happiness, dropping activities/interests, and low satisfaction with life (all P's < 0.01). CONCLUSION: Depressive symptoms preceded cognitive impairment in a population based sample of the oldest old.

Precise Exchange of the Helper-Component Proteinase Cistron Between Soybean mosaic virus and Clover yellow vein virus: Impact on Virus Viability and Host Range Specificity.

Soybean mosaic virus and Clover yellow vein virus are two definite species of the genus Potyvirus within the family Potyviridae. Soybean mosaic virus-N (SMV-N) is well adapted to cultivated soybean (Glycine max) genotypes and wild soybean (G. soja), whereas it remains undetectable in inoculated broad bean (Vicia faba). In contrast, clover yellow vein virus No. 30 (ClYVV-No. 30) is capable of systemic infection in broad bean and wild soybean; however, it infects cultivated soybean genotypes only locally. In this study, SMV-N was shown to also infect broad bean locally; hence, broad bean is a host for SMV-N. Based on these observations, it was hypothesized that lack of systemic infection by SMV-N in broad bean and by ClYVV-No. 30 in cultivated soybean is attributable to the incompatibility of multifunctional helper-component proteinase (HC-Pro) in these hosts. The logic of selecting the HC-Pro cistron as a target is based on its established function in systemic movement and being a relevant factor in host range specificity of potyviruses. To test this hypothesis, chimeras were constructed with precise exchanges of HC-Pro cistrons between SMV-N and ClYVV-No. 30. Upon inoculation, both chimeras were viable in infection, but host range specificity of the recombinant viruses did not differ from those of the parental viruses. These observations suggest that (i) HC-Pro cistrons from SMV-N and ClYVV-No. 30 are functionally compatible in infection despite 55.6 and 48.9% nucleotide and amino acid sequence identity, respectively, and (ii) HC-Pro cistrons from SMV-N and ClYVV-No. 30 are not the determinants of host specificity on cultivated soybean or broad beans, respectively.

Design of a forward view antenna for prostate imaging at 7 T.

PURPOSE: To design a forward view antenna for prostate imaging at 7 T, which is placed between the legs of the subject in addition to a dipole array. MATERIALS AND METHODS: The forward view antenna is realized by placing a cross-dipole antenna at the end of a small rectangular waveguide. Quadrature drive of the cross-dipole can excite a circularly polarized wave propagating along the axial direction to and from the prostate region. Functioning of the forward view antenna is validated by comparing measurements and simulations. Antenna performance is evaluated by numerical simulations and measurements at 7 T. RESULTS: Simulations of B1+ on a phantom are in good correspondence with measurements. Simulations on a human model indicate that the signal-to-noise ratio (SNR), specific absorption rate (SAR) efficiency and SAR increase when adding the forward view antenna to a previously published dipole array. The SNR increases by up to 18% when adding the forward view antenna as a receive antenna to an eight-channel dipole array in vivo. CONCLUSIONS: A design for a forward view antenna is presented and evaluated. SNR improvements up to 18% are demonstrated when adding the forward view antenna to a dipole array.

Genetic diversity does not explain variation in extra-pair paternity in multiple populations of a songbird.

Many songbirds are socially monogamous but genetically polyandrous, mating with individuals outside their pair bonds. Extra-pair paternity (EPP) varies within and across species, but reasons for this variation remain unclear. One possible source of variation is population genetic diversity, which has been shown in interspecific meta-analyses to correlate with EPP but which has limited support from intraspecific tests. Using eight populations of the genetically polyandrous red-winged blackbird (Agelaius phoeniceus), including an island population, we investigated whether population-level differences in genetic diversity led to differences in EPP. We first measured genetic diversity over 10 microsatellite loci and found, as predicted, low genetic diversity in the island population. Additional structure analyses with multilocus genotypes and mtDNA showed the island population to be distinct from the continental populations. However, the island population's EPP rate fell in the middle of the continental populations' distribution, whereas the continental populations themselves showed significant variation in EPP. This result suggests that genetic diversity by itself is not a predictor of EPP rate. We discuss reasons for the departure from previous results, including hypotheses for EPP that do not solely implicate female-driven behaviour.

The imaging prevalence of osteolytic metastasis or multiple myeloma presenting as a periprosthetic lucency in the hip.

OBJECTIVE: The purpose of this article is to determine how often a malignant process presents as a lucency near a hip prosthesis, and to classify the frequency and distribution of differential diagnoses of these lytic lesions, and to determine their disposition. MATERIALS AND METHODS: Hip and pelvis imaging examinations obtained from January 1998 to June 2008 were text searched (1,164,560 reports) to identify patients with hip prostheses (3508 patients); the records were then searched and individually reviewed to identify periprosthetic lucency (2036 reports; 176 patients). The most likely cause for the lucency, as determined by the interpreting radiologist, was recorded. Malignancy was confirmed in all cases. Malignancy was excluded by biopsy for some patients but by clinical follow-up or at the time of revision, if performed, for most patients. Prevalence rates and 95% CIs were calculated. RESULTS: The overall prevalence of periprosthetic lucency was 5.02%. The prospective diagnoses suggested included loosening or infection (37.5%), degenerative cysts (19.3%), metastases (23.3%), multiple myeloma (14.8%), and metastasis of previously unknown malignancy (3.4%). The prevalence of metastases or multiple myeloma near a hip prosthesis was 1.54%; however, each of these patients had a known prior diagnosis of bone metastases, multiple myeloma, or primary bone malignancy. CONCLUSION: Among the 2036 examinations with periprosthetic lucency, there were no instances of new malignancy, metastasis, or myeloma. These results suggest that it is statistically unlikely that a lucency near a hip prosthesis represents the first presentation of malignancy or metastases, regardless of how large or aggressive it may appear on imaging.

Prevalence and associated factors of modern contraceptive discontinuation among sexually active married women in Nigeria.

BACKGROUND: Contraceptive discontinuation for reasons other than the desire for pregnancy is associated with a high rate of unintended pregnancies leading to unsafe abortions, maternal morbidity and mortality. In Nigeria, little is known about modern contraceptive discontinuation using the calendar data. METHODS: A cross-sectional research design from the 2018 Nigeria Demographic and Health Surveys (NDHS) women's dataset was used to examine the prevalence and associated factors of modern contraceptive discontinuation among sexually active married women in Nigeria. A weighted sample size of 3,353 currently sexually active married or in union women who have ever used a modern contraceptive 5 years before the survey and with complete reproductive histories and are not sterilised or declared infecund was analysed. Data were analysed and displayed using frequency tables and charts, chi-square test, and binary logistic regression model at 5% level of significance. RESULTS: The prevalence of modern contraceptive discontinuation was 35.8% (1199) with 45.8% (549) of the women discontinuing using modern contraceptives while at risk of pregnancy. The most modern method discontinued was Injectables (25.2%) while the commonest reason for modern method discontinuation was because they wanted to become pregnant (36.1%). Associated factors of modern contraceptive discontinuation among sexually active married women in Nigeria were: marital duration (aOR = 3.0; 95%CI: 1.5-6.2), visitation to a health facility in the last 12 months before the survey (aOR = 0.6; 95%CI: 0.4-0.8), education (aOR = 2.0; 95%CI: 1.2-3.4) and region of residence (aOR = 2.7; 95%CI: 1.6-4.7). CONCLUSION: Modern contraceptive discontinuation among the study respondents was high. Region of residence, health facility visitation and marital duration were significantly associated with modern contraceptive discontinuation. The study suggests that health care providers should address the discontinuation of contraception through counselling, particularly among women who reside in the region of high prevalence of contraceptive discontinuation, short-term users as well as strengthen the use of contraception among those who are still at risk of becoming pregnant. Governments and stakeholders should also partner with private sectors to make health care accessible to women by bring health facilities closer to them to improve facility visitation.

The role of Staphylococcal enterotoxin in atopic keratoconjunctivitis and corneal ulceration.

BACKGROUND: Patients with atopic eczema frequently experience colonization with Staphylococcus aureus that is directly correlated with the eczema severity. We hypothesized that S. aureus-secreted enterotoxins (SE) are involved in the pathophysiology of atopic keratoconjunctivitis (AKC). METHODS: A total of 45 subjects (18 with AKC, nine vernal keratoconjunctivitis (VKC), eight seasonal allergic conjunctivitis (SAC), and ten healthy volunteers) were enrolled. Slit lamp examinations, including fluorescein staining, were performed. Scraped samples were collected from the upper tarsal conjunctiva, lower conjunctival sacs, and the skin around the eyelid margins. Superantigen (SAg) genes were detected using polymerase chain reaction (PCR). RESULTS: Among 45 cases, S. aureus was detected significantly more in AKC patients than VKC patients (P = 0.026), SAC patients (P = 0.0003), and healthy volunteers (P = 0.0001). SAg genes were detected in 11 patients. SEB (2/11), SEG (8/11), and SEI (8/11) were detected, but no other SE. There was a significant difference in SE detection between AKC and SAC patients (P = 0.03). In severe types of ocular allergic disease such as AKC and VKC (N = 27), SE was detected in six of ten patients with corneal ulcers and two of 17 patients without corneal ulcers. SE was detected in significantly more patients with corneal ulcers (P = 0.025). CONCLUSIONS: In patients with AKC, S. aureus and SE were detected more frequently compared with other patients and healthy volunteers, especially in association with corneal ulceration suggesting a role of SE. So far, it is unknown whether SE leads to tissue damage of the cornea by initiating an immune response or has direct toxic effects.

Do female parasitoid wasps recognize and adjust sex ratios to build cooperative relationships?

Sex allocation theories provide excellent opportunities to investigate not only the extent to which individuals' behaviour is adaptive, but also how they use relevant information for their decision-making. Here, we investigated whether female parasitoid wasps recognize the sex ratios of other females and adjust their laying sex ratios accordingly. Specifically, we tested the prediction of reciprocal cooperation over sex allocation. Theory predicts more female-biased (cooperative) sex ratios than in the interest of individual benefit, when a restricted number of ovipositing females interact for a long period and their offspring mate within the natal patch. This is because the female-biased sex ratio reduces competition for mates among the male offspring of the females and increases the overall reproductive productivity of the patch. In this case, females would be expected to respond to more even (noncooperative) sex ratios by others and to retaliate by also producing a less female-biased sex ratio to avoid exploitation by defectors. However, contrary to this prediction, our experiment using a sterile male technique showed that female Melittobia australica did not change their offspring sex ratios in response to the sex ratios produced by other females. This suggests that their extremely female-biased sex ratios cannot be explained by reciprocity. A meta-analysis of studies examining sex recognition ability in parasitoid wasps also did not support the predicted pattern of relevant sex ratio adjustment, suggesting that parasitoid females do not possess this ability. Here, we discuss the conditions necessary for the evolution of reciprocity linked to recognition ability.

Lessons learned from two clinical trials on nutritional supplements to reduce aggressive behaviour.

BACKGROUND: Setting up and conducting a randomised controlled trial (RCT) has many challenges-particularly trials that include vulnerable individuals with behavioural problems or who reside in facilities that focus on care as opposed to research. These populations are underrepresented in RCTs. APPROACH: In our paper, we describe the challenges and practical lessons learned from two RCTs in two care settings involving long-stay psychiatric inpatients and people with intellectual disabilities. We describe five main difficulties and how these were overcome: (1) multisite setting, (2) inclusion of vulnerable participants, (3) nutritional supplements and placebos, (4) assessment of behavioural outcomes, and (5) collecting bio samples. CONCLUSIONS: By sharing these practical experiences, we hope to inform other researchers how to optimally design their trials, while avoiding and minimising the difficulties that we encountered, and to facilitate the implementation of a trial. Both trials were registered in the Clinical Trials Register (RCT A: NCT02498106; RCT B: NCT03212092).

Evaluation of a Dedicated Radiofrequency Carotid PET/MRI Coil.

Carotid radiofrequency coils inside a PET/MRI system can result in PET quantification errors. We compared the performance of a dedicated PET/MRI carotid coil against a coil for MRI-only use. An 18F-fluorodeoxyglucose (18F-FDG) phantom was scanned without and with an MRI-only coil and with the PET/MRI coil. The decay-corrected normalized activity was compared for the different coil configurations. Eighteen patients were scanned with the three coil configurations. The maximal standardized uptake values (SUVmax) and signal-to-noise ratios (SNR) were calculated. Repeated measures ANOVA was performed to assess the differences in SUVmax and SNR between the coil configurations. In the phantom study, the PET/MRI coil demonstrated a slight decrease (<5%), while the MRI-only coil showed a substantial decrease (up to 10%) in normalized activity at the position of coil elements compared to no dedicated coil configuration. In the patient study, the SUVmax values for both no surface coil (3.59 ± 0.15) and PET/MRI coil (3.54 ± 0.15) were significantly higher (p = 0.03 and p = 0.04, respectively) as compared to the MRI-only coil (3.28 ± 0.16). No significant difference was observed between PET/MRI and no surface coil (p = 1.0). The SNR values for both PET/MRI (7.31 ± 0.44) and MRI-only (7.62 ± 0.42) configurations demonstrated significantly higher (p < 0.001) SNR values as compared to the no surface coil (3.78 ± 0.22), while no significant difference was observed in SNR between the PET/MRI and MRI-only coil (p = 1.0). This study demonstrated that the PET/MRI coil can be used for PET imaging without requiring attenuation correction while acquiring high-resolution MR images.

Characterization of T cell repertoire changes in acute Kawasaki disease.

Kawasaki disease (KD) is an acute multisystem vasculitis of unknown etiology that is associated with marked activation of T cells and monocyte/macrophages. Using a quantitative polymerase chain reaction (PCR) technique, we recently found that the acute phase of KD is associated with the expansion of T cells expressing the V beta 2 and V beta 8.1 gene segments. In the present work, we used a newly developed anti-V beta 2 monoclonal antibody (mAb) and studied a new group of KD patients to extend our previous PCR results. Immunofluorescence analysis confirmed that V beta 2-bearing T cells are selectively increased in patients with acute KD. The increase occurred primarily in the CD4 T cell subset. The percentages of V beta 2+ T cells as determined by mAb reactivity and flow cytometry correlated linearly with V beta expression as quantitated by PCR. However, T cells from acute KD patients appeared to express proportionately higher levels of V beta 2 transcripts per cell as compared with healthy controls or convalescent KD patients. Sequence analysis of T cell receptor beta chain genes of V beta 2 and V beta 8.1 expressing T cells from acute KD patients showed extensive junctional region diversity. These data showing polyclonal expansion of V beta 2+ and V beta 8+ T cells in acute KD provide additional insight into the immunopathogenesis of this disease.

Competition between relatives and the evolution of dispersal in a parasitoid wasp.

Evolutionary theory predicts that levels of dispersal vary in response to the extent of local competition for resources and the relatedness between potential competitors. Here, we test these predictions by making use of a female dispersal dimorphism in the parasitoid wasp Melittobia australica. We show that there are two distinct female morphs, which differ in morphology, pattern of egg production, and dispersal behaviour. As predicted by theory, we found that greater competition for resources resulted in increased production of dispersing females. In contrast, we did not find support for the prediction that high relatedness between competitors increases the production of dispersing females in Melittobia. Finally, we exploit the close links between the evolutionary processes leading to selection for dispersal and for biased sex ratios to examine whether the pattern of dispersal can help distinguish between competing hypotheses for the lack of sex ratio adjustment in Melittobia.

Premature coronary artery calcification is associated with disease duration and bone mineral density in young female systemic lupus erythematosus patients.

Our objective was to evaluate the relevance of traditional and disease-related cardiovascular risk factors and of bone mineral density for premature coronary artery calcification in young patients with systemic lupus erythematosus. Ninety-four female patients with systemic lupus erythematosus with disease durations >5 years and <45 years were consecutively selected. Cardiovascular risks (diabetes mellitus, arterial hypertension, dyslipoproteinemia, smoking, family history, body mass index, ovarian and renal insufficiency) and systemic lupus erythematosus-related risk factors (disease duration, ACR criteria, modified SLICC/ ACR, SLEDAI and treatment) were evaluated. Bone mineral density was assessed by dual X-ray absorptiometry. Coronary artery calcification was determined by computed tomography. Coronary artery calcification was identified in 12 (12.7%) patients and was associated with a higher frequency of patients with cardiovascular risks (p = 0.001), higher number of cardiovascular risks (p = 0.002), age (p = 0.025), disease duration (p = 0.011) and SLICC (p=0.011). Individual analysis of cardiovascular risks demonstrated that menopause (p = 0.036), dyslipidemia (p = 0.003) and hypertension (p = 0.006) were significantly associated with coronary artery calcification. In addition, coronary artery calcification was associated with a lower whole body bone mineral density (p = 0.013). Multiple logistic regression analysis using cardiovascular risks, age, disease duration, SLICC and whole body bone mineral density revealed that only disease duration (p = 0.038) and whole body bone mineral density (p = 0.021) remained significant for coronary artery calcification. In conclusion, we found that disease duration and decreased bone mineral density are independent predictors for premature coronary calcification in young women with systemic lupus erythematosus, suggesting a common underlying mechanism.

Enzyme replacement therapy stabilizes obstructive pulmonary Fabry disease associated with respiratory globotriaosylceramide storage.

Fabry disease is an X-linked glycosphingolipidosis caused by a deficiency of α-galactosidase A, a lysosomal enzyme. Symptoms in hemizygous males and heterozygous females are due to lysosomal storage of globotriaosylceramide in the central and peripheral nervous system, vascular endothelium, cardiac valves and myocytes, gastrointestinal tract, and renal epithelium. Pulmonary involvement is also a recognized manifestation of Fabry disease, but histopathological evidence of pulmonary lysosomal storage is scant. We report a 51-year-old woman with a G43R α-galactosidase A mutation and normal spirometry testing 2.5 years prior to presentation, who experienced a dry, nonproductive cough that persisted despite treatment with antibiotics and bronchodilators. Spirometry demonstrated a mixed restrictive/obstructive pattern as well as impaired gas exchange. Patchy ground-glass pulmonary interstitial infiltrates were found on plain radiography and computerized tomography. She underwent an open lung biopsy that demonstrated peribronchiolar fibrosis and smooth-muscle hyperplasia. Prominent inclusion bodies of the bronchiolar/arteriolar smooth muscle and endothelium were present. Electron microscopy indicated the inclusion bodies were lamellated zebra bodies consistent with globotriaosylceramide storage. Enzyme replacement therapy (ERT) with agalsidase-beta was instituted. Since initiation of therapy, she occasionally has a dry cough but markers of obstructive lung disease have remained stable in the past 4 years. This report demonstrates that pulmonary involvement in Fabry disease is due to lysosomal storage, and suggests that ERT is capable of stabilizing pulmonary Fabry disease. However, progressive worsening of her total lung capacity indicates that ERT cannot reverse the ongoing process of fibrosis also seen in Fabry disease.

[Recurrence patterns and prognosis in lung cancer patients with positive pleural lavage cytology at surgery].

Recurrence patterns and prognosis in lung cancer patients with positive pleural lavage cytology (PLC) at surgery have not been completely understood. From January 2001 to October 2007, we performed PLC on 195 patients undergoing thoracotomy for lung cancer. Fourteen (7.2%) of 195 patients had positive PLC findings. Twenty seven patients who underwent limited surgery due to complication were excluded from the further investigation. Some form of recurrence was observed in 33 (21.2%) of 156 patients with negative PLC, and in 8 (66.7%) of 12 patients with positive PLC (p < 0.05). The local recurrence was observed in 13 (39.4%) of 33 patients who have recurrence with negative PLC and was observed in 4 (25%) of 8 patients who have recurrence with positive PLC (p = 0.45). The survival rate of patients with positive PLC was significantly worse than that of patients with negative PLC (p < 0.05), and was as low as that of patients with macroscopic malignant effusion. The multivariate analysis demonstrated PLC was independent prognostic factor. PLC is an easy procedure and is an important prognostic factor, and should be routinely performed in the lung cancer operation.

Lymph node blood vessels provide exit routes for metastatic tumor cell dissemination in mice.

During metastasis, malignant cells escape the primary tumor, intravasate lymphatic vessels, and reach draining sentinel lymph nodes before they colonize distant organs via the blood circulation. Although lymph node metastasis in cancer patients correlates with poor prognosis, evidence is lacking as to whether and how tumor cells enter the bloodstream via lymph nodes. To investigate this question, we delivered carcinoma cells into the lymph nodes of mice by microinfusing the cells into afferent lymphatic vessels. We found that tumor cells rapidly infiltrated the lymph node parenchyma, invaded blood vessels, and seeded lung metastases without involvement of the thoracic duct. These results suggest that the lymph node blood vessels can serve as an exit route for systemic dissemination of cancer cells in experimental mouse models. Whether this form of tumor cell spreading occurs in cancer patients remains to be determined.

1,25-Dihydroxyvitamin D3 upregulates the phosphatidylinositol signaling pathway in human keratinocytes by increasing phospholipase C levels.

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) induces the differentiation of normal human keratinocytes, in part by increasing their basal intracellular calcium levels (Cai) over a period of hours. Agonists such as ATP acting through membrane receptors cause an immediate but transient increase in Cai accompanied by an increase in inositol trisphosphate (IP3). Treatment of keratinocytes for 24 h with 1 nM 1,25(OH)2D3 resulted in a two- to four-fold potentiation of the Cai response of these cells to ATP. This potentiation was inhibitable with cycloheximide, unaccompanied by a change in total intracellular calcium pools, but associated with an increase in basal IP3 levels and ATP-stimulated IP3 production. Treatment with 1,25(OH)2D3 raised the protein and mRNA levels of phospholipase C isoenzymes, particularly phospholipase C-beta 1 in a dose-dependent manner. These studies indicate that 1,25(OH)2D3 modulates the keratinocyte signal transduction pathway by induction of phospholipase isoenzymes, a previously undescribed action for this hormone.

Clinical role for a superantigen in Yersinia pseudotuberculosis infection.

Yersinia pseudotuberculosis is an enteric pathogen that causes a variety of clinical symptoms in the human. Recently, we reported the production of a superantigen (Y. pseudotuberculosis-derived mitogen, YPM) by this organism and characterized the gene structure of ypm. To further study the potential pathogenic role of YPM in Y. pseudotuberculosis infection, we assayed IgG anti-YPM antibodies and T cell antigen receptor-Vbeta expression of the T cells in peripheral blood and in mesenteric lymph node in patients acutely infected with Y. pseudotuberculosis. 20 out of 33 patients (61%) had an elevated antibody titer compared with healthy controls (P = 0.0001). Patients with systemic symptoms such as lymphadenopathy, transient renal dysfunction, and arthritis had significantly higher titers of anti-YPM than patients with gastrointestinal tract symptoms alone. T cells bearing the Vbeta3 gene segment were significantly increased (P = 0.009) among acute phase patients compared with healthy children. During the convalescence phase of the illness, there was a reduction in the abnormal level of Vbeta3 T cells. Moreover, in the mesenteric lymph node, an elevated level of Vbeta3 T cells compared with peripheral blood and a sequence diversity in the junctional region of the T cell antigen receptor beta-chain containing Vbeta3 element was observed in one patient. Together, these findings suggest that YPM was produced in vivo and played an important role in the pathogenesis of Y. pseudotuberculosis infection.

Modulation of cell growth, differentiation, and production of interleukin-3 by 1 alpha,25-dihydroxyvitamin D3 in the murine myelomonocytic leukemia cell line WEHI-3.

The effect of 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3], the active form of vitamin D3, on the relation between cell growth and differentiation was examined in a murine myelomonocytic leukemia cell line WEHI-3 which is known to produce high levels of interleukin-3. 1 alpha,25(OH)2D3 markedly inhibited proliferation of WEHI-3 cells in a time- and dose-dependent manner. Flow cytometric analysis of the cell cycle by a double staining method using fluorescein isothiocyanate-conjugated anti-bromodeoxyuridine and propidium iodide revealed that 1 alpha,25(OH2D3 increased the proportion and the number of cells accumulating in the G0-G1 phase and decreased those in the S phase. The phenotype of the surface antigens of the cells was of the T-cell lineage, but the cells became positive in macrophage-associated surface markers (Mac-1 and Ia) after treatment with 1 alpha,25(OH)2D3. The vitamin induced phagocytic activity, appearance of Fc receptors, nitroblue tetrazolium-reducing activity, and nonspecific esterase activity, indicating that the vitamin induces the cells to differentiate into macrophages. Furthermore, 1 alpha,25(OH)2D3 inhibited interleukin-3 production by the cells in a time- and dose-dependent manner. These results suggest that 1 alpha,25(OH)2D3 inhibits proliferation of WEHI-3 cells by blocking transition of the cells from the G0-G1 to the S phase, resulting in induction of the G0-G1-arrested cells to differentiate into macrophages. The relation between the suppression by 1 alpha,25(OH)2D3 of cell growth and interleukin-3 production remains to be elucidated in the future.