Synergistic effect of 1,25-dihydroxyvitamin D3 and retinoic acid in inducing U937 cell differentiation.

We examined the effects of retinoic acid (RA), 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3), and its synthetic analogue, 22-oxa-1,25-(OH)2D3, on differentiation of U937 cells by studying the cellular growth, surface marker expression and cytosolic free Ca2+ concentration ([Ca2+]i). RA inhibited cellular growth but did not induce expression of Mo2 (CD14), a monocyte/macrophage specific surface marker. To the contrary, 1,25-(OH)2D3 did not inhibit cellular growth, but increased CD 14-positive cells. Simultaneous addition of 1,25-(OH)2D3 and RA had no additive effect on cellular growth inhibition or CD14 expression. With regard to [Ca2+]i, however, 5 days' incubation with either of them increased the basal [Ca2+]i level and induced U937 cells to respond to formyl-methionyl-leucyl-phenylalanine (FMLP). When the cells were incubated with both 10(-6) M RA and 10(-8) M 1,25-(OH)2D3, basal [Ca2+]i was higher and FMLP caused a greater increase in [Ca2+]i than when only RA or 1,25-(OH)2D3 was added. These data suggest that RA and 1,25-(OH)2D3 induce monocytoid differentiation in U937 cells through different pathways and act synergistically in the differentiation process. The 22-oxa-1,25-(OH)2D3 induced CD14 expression, basal [Ca2+]i increase and [Ca2+]i response to FMLP, but did not cause cellular growth inhibition in U937 cells, and in these points, 22-oxa-1,25-(OH)2D3 exhibited no significantly different effects from 1,25-(OH)2D3. Thus, 22-oxa-1,25-(OH)2D3 has the same potent activity as 1,25-(OH)2D3 in inducing differentiation of U937 cells.     

Neurotized nevi of the oral mucosa: an immunohistochemical and ultrastructural analysis of nevic corpuscles

BACKGROUND: Nevic corpuscle (NC), a stacked lamellar structure reminiscent of Meissner corpuscle, is frequently observed in dermal melanocytic nevi. Although the heading 'neurotized' is classically used for these nevi, the exact neural nature of NC has been a topic of considerable debate. Neurotized nevi have received little attention in the dental literature, and there was no information on NC in oral melanocytic nevi. METHODS: Six cases of oral intramucosal nevi with a significant number of NC (two completely and four partially neurotized nevi) were examined immunohistochemically and ultrastructurally. RESULTS: NC was composed of closely piled laminar cells devoid of visible melanin. NC and associated spindle nevus cells were immunopositive for S-100 protein but negative for HMB-45, myelin basic protein and epithelial membrane antigen. Within NC, no reactivity for neurofilament protein, protein gene product 9.5 or peripherin was evident. Numerous CD34-positive dendritic cells were located between nevus cells and often encircled NC. Ultrastructurally, NC consisted of concentrically layered elongated cells with a slender lamellated cytoplasm rich in thin filaments and pinocytotic vesicles. Their cytoplasmic processes were focally covered by external basal lamina and continuous to spindle nevus cells. Occasional NC cells contained a few melanosomes. There was no interposed axon in NC. CONCLUSIONS: Despite the close resemblance to Meissner corpuscle, NC showed no axonal supply. NC cells lacked terminal Schwannian differentiation and appeared to be modified melanocytes with some perineurial ultrastructural characteristics. The presence of CD34-positive cells, presumably corresponding to endoneurial fibroblasts, further supports an organizational relationship of NC and peripheral nerve sheath elements.     

Overestimation of myocardial viability due to an increase in thallium uptake by the lung

Thallium lung uptake (TL-uptake) was usually treated as background for myocardial image and increase of TL-uptake in exercise test was considered as marker of depressed cardiac function. It was reported that marked increase of TL-uptake in patients with acute myocardial infarction (AMI) corresponded to acute severe congestive heart failure. Here effect of TL-uptake on myocardial planar images was studied in 61 patients with AMI. In acute phase anterior, LAO 30 degrees and LAO 60 degrees myocardial images were collected. In 29 cases of 61 cases 3 to 6 hours delayed images could be collected. Each myocardial images was divided to 3 division and both images were compared. In 5 of 6 patients with marked increase of TL-uptake new defects were noted in anterior division of delayed images and in one case also in lateral division. In 7 patients of 12 patients with moderate increase of TL-uptake new defects were also noted in delayed images, i.e. 3 in anterior, 3 in inferior and one in apical division. It was concluded that over estimation of myocardial viability due to marked increase of TL-uptake was often noted in patients with AMI accompanying severe congestion. It became clear that delayed images were necessary to correctly estimate myocardial viability in such case.     

Surgical treatment of acute pulmonary embolism--report of two cases

Two surgical cases of acute pulmonary embolism with severe cardiocirculatory impairment were reported. In the first case, emergent open pulmonary embolectomy with cardiopulmonary bypass was not effective, and multiple and organized emboli were indicative. In the second case, complete pulmonary thromboembolectomy was accomplished under extracorporeal circulation with remarkable hemodynamic improvement. It was suggested that urgent pulmonary angiography was necessary for definitive diagnosis and medical treatment, and that indications for pulmonary embolectomy included all patients with massive emboli in the main branches of the pulmonary artery. Monitoring of pulmonary arterial pressure was important to assess the effect of thrombolytic therapy, and the system of emergent cardiopulmonary bypass was required for immediate and effective cardiopulmonary resuscitation.     

Cross-sectional study of allergic disorders associated with breastfeeding in Japan: The Ryukyus Child Health Study

Uncertainties remain as to whether breastfeeding is protective against childhood allergic disorders. Positive relationships of breastfeeding with asthma and atopic eczema were observed in two previous Japanese studies. This cross-sectional study investigated the association between the feeding pattern after birth and the prevalence of allergic disorders during the past 12 months in Japanese schoolchildren. Study subjects were 24,077 children aged 6-15 yr in Okinawa. The outcomes were based on diagnostic criteria from the International Study of Asthma and Allergies in Childhood. Allowance was made for age, sex, number of siblings, smoking in the household, paternal and maternal history of asthma, atopic eczema, and allergic rhinitis, and paternal and maternal educational level. Breastfeeding, regardless of exclusivity, for 13 months or longer and exclusive breastfeeding for 4-11 months were independently associated with a higher prevalence of atopic eczema, particularly among children without a parental allergic history. A clear positive dose-response relationship was observed between prolonged duration of breastfeeding, regardless of exclusivity, but not exclusive breastfeeding, and the prevalence of atopic eczema. We found a significant positive trend for atopic eczema across the three categories (formula milk, partial and exclusive breastfeeding) in the first 4 months of life although the odds ratio for exclusive breastfeeding was not statistically significant. No material association was found between the feeding pattern after birth and the prevalence of wheeze or allergic rhinoconjunctivitis. Prolonged breastfeeding may be associated with a higher prevalence of atopic eczema in Japanese children.     

Differential expression of the beta I- and beta II-PKC subspecies in the postnatal developing rat brain; an immunocytochemical study.

Differential expression of protein kinase C subspecies, beta I- and beta II-PKC, derived from a single gene by alternative splicing was evidenced in the postnatal developing rat brain. Immunoblot analysis of the PKC subspecies in the whole developing brain showed that beta I-PKC was present at birth and then gradually increased, while beta II-PKC was not present at birth or on postnatal day 3, then increased rapidly from day 7 to the maximum value seen in the adult brain. Under light microscopy, beta I-PKC immunoreactivities seen at birth were the most intense in the brainstem and intense in the diagonal bundle and globus pallidus. beta I-PKC immunoreactivities in these neurons weakened from day 7 and disappeared in the adult brain, while in the cerebral cortex, triangular septal nucleus and pontine nucleus beta I-PKC immunoreactivities were week at birth and then gradually increased. beta II-PKC immunoreactivities were first visible in neurons on day 7 and increased progressively. beta I- and beta II-PKCs were not co-localized in a neuron, as far as examined. The immunoreactivities of beta I-PKC at birth were localized in growth cone-like structures as well as in the dendrites and perikarya. Similarly, alpha-PKC was also present at birth in the growth cone-like structure. Immunoblot analysis revealed that beta I-PKC was present at birth in the growth cone-rich fraction from the hindbrain but not in that from the forebrain, while alpha-PKC was found in the growth cone-rich fraction from both the forebrain and the hindbrain. beta II- and gamma-PKC were not detected in the growth cone-rich fraction from either forebrain or hindbrain. These findings suggest that beta I- and beta II-PKC play a role in different stages of development and in different neurons; both beta-subspecies may be involved in postnatal developing neuronal functions while only beta I-PKC plays functional roles in the growth cone, in the prenatal developmental stage.     

Immunohistological study on the expression of proliferating cell nuclear antigen (PCNA/cyclin) in human colorectal lesions]

The purpose of this study was to clarify the significance of immunohistological staining for PCNA/cyclin in human colorectal lesions. Our results: The PCNA-positive cells existed at the bottom of colonic tubuli in the normal and hyperplastic conditions. In the neoplastic lesions, however, the positive cells were existed at the relatively surface of the mucosa (chi 2: P less than 0.01) and distributed irregularly from the bottom to the top of carcinoma tissue. These results suggested that immunohistological staining for PCNA would specifically detect the cell proliferation and be beneficial for practical use and clinical application of the diagnosis of the colorectal lesions.