Intercellular Interactions of an Adipogenic CXCL12-Expressing Stromal Cell Subset in Murine Bone Marrow

Bone marrow houses a multifunctional stromal cell population expressing C-X-C motif chemokine ligand 12 (CXCL12), termed CXCL12-abundant reticular (CAR) cells, that regulates osteogenesis and adipogenesis. The quiescent pre-adipocyte-like subset of CXCL12⁺ stromal cells (“Adipo-CAR” cells) is localized to sinusoidal surfaces and particularly enriched for hematopoiesis-supporting cytokines. However, detailed characteristics of these CXCL12⁺ pre-adipocyte-like stromal cells and how they contribute to marrow adipogenesis remain largely unknown. Here we highlight CXCL12-dependent physical coupling with hematopoietic cells as a potential mechanism regulating the adipogenic potential of CXCL12⁺ stromal cells. Single-cell computational analyses of RNA velocity and cell signaling reveal that Adipo-CAR cells exuberantly communicate with hematopoietic cells through CXCL12-CXCR4 ligand-receptor interactions but do not interconvert with Osteo-CAR cells. Consistent with this computational prediction, a substantial fraction of Cxcl12-creER⁺ pre-adipocyte-like cells intertwines with hematopoietic cells in vivo and in single-cell preparation in a protease-sensitive manner. Deletion of CXCL12 in these cells using Col2a1-cre leads to a reduction of stromal-hematopoietic coupling and extensive marrow adipogenesis in adult bone marrow, which appears to involve direct conversion of CXCL12⁺ cells to lipid-laden marrow adipocytes without altering mesenchymal progenitor cell fates. Therefore, these findings suggest that CXCL12⁺ pre-adipocyte-like marrow stromal cells prevent their premature differentiation by maintaining physical coupling with hematopoietic cells in a CXCL12-dependent manner, highlighting a possible cell-non-autonomous mechanism that regulates marrow adipogenesis. © 2021 American Society for Bone and Mineral Research (ASBMR).     

Isolation of putative dengue virus receptor molecules by affinity chromatography using a recombinant E protein ligand

Nucleotide sequences coding for the full-length envelope (E) glycoprotein gene of dengue virus type 4 was amplified using an RT-PCR method from infected C6/36 cells and cloned into pPROEx-Hta expression vector. The expression of the recombinant E protein in Escherichia coli was confirmed by Western blot using a polyclonal anti-dengue polyclonal antibody. The His-tagged fusion protein was obtained from the bacterial cellular extracts in almost pure form by immobilized metal affinity chromatography and the recombinant protein retained its ability to bind to 40 and 45 kDa proteins, previously described as putative receptors for dengue virus in C6/36 cells. To purify the 40 and 45 kDa molecules, a total protein extract from C6/36 cells was passed through an affinity chromatography column using immobilized recombinant E protein. After washing with isotonic buffer, elution was accomplished using a high salt buffer. The two proteins obtained, with molecular weights of 40 and 45 kDa, were recognized by dengue 4 virus, in virus overlay protein binding assay. This procedure allows further characterization of molecules that could be involved in dengue binding and entry.     

Self-rated health and mortality in the NHANES-I Epidemiologic Follow-up Study.

The ability of self-rated health status to predict mortality was tested with data from the National Health and Nutrition Examination Survey (NHANES-I) Epidemiologic Follow-Up Study (NHEFS), conducted from 1971-84. The sample consists of adult NHANES-I respondents ages 25-74 years (N = 6,440) for whom data from a comprehensive physical examination at the initial interview and survival status at follow-up are available. Self-rated health consists of the response to the single item, "Would you say your health in general is excellent, very good, good, fair, or poor?" Proportional hazards analyses indicated that, net of its association with medical diagnoses given in the physical examination, demographic factors, and health related behaviors, self-rated health at Time 1 is associated with mortality over the 12-year follow-up period among middle-aged males, but not among elderly males or females of any age.     

Renal tubular acidosis in the Silver-Russell syndrome

Several patients with the Silver-Russell syndrome (SRS) attending our Genetics Clinic were diagnosed as having persistent metabolic acidosis. Since this abnormality has not been reported previously in the SRS, we reexamined 33 SRS patients to evaluate the frequency and type of metabolic acidosis, the clinical and laboratory findings, and the growth pattern in SRS patients with and without metabolic acidosis. Among them, 14 had a consistent decrease in HCO levels. Renal studies in acidotic patients showed urine pH of 5.8 and 24 h urine calcium of <2.4 mg/kg/24 h; serum creatinine, excretion of glucose, and aminoacids were normal, as were renal ultrasound and excretory urography findings. These data supported the diagnosis of renal tubular acidosis, probably type II; the patients were treated with oral bicarbonate and acidosis was corrected successfully. Clinical manifestations were similar in acidotic and non-acidotic patients. The nutritional indices at diagnosis and at last evaluation (at least 8 months after diagnosis) were abnormally low in all patients; however, acidotic patients, treated with bicarbonate, showed an improvement of nutritional status particularly in the weight/height index, although the difference between groups after follow-up did not reach statistical significance. We suggest that metabolic acidosis due to renal tubular acidosis, probably type II, may occur in children with the SRS and should be looked for and treated in all patients. © 1995 Wiley-Liss, Inc.     

Calcitriol oral pulse therapy in children with renal osteodystrophy

A 6-month protocol of oral pulse calcitriol was used in nine uraemic children (2–14 years old) on dialysis who presented with renal osteodystrophy. Calcitriol was administered twice a week, 4 g per dose for patients over 30 kg and 3g for patients less than 30 kg. Plasma levels of parathyroid hormone, calcium, phosphorus and alkaline phosphatase were carefully controlled during the study. Parathyroid hormone levels decreased by 68% and 56% by the 2nd and 6th months of treatment in seven patients, while they remained unchanged in two patients with focal segmental glomerulosclerosis and massive proteinuria. Eight hypercalcaemic episodes from 77 determinations were observed, all of them recovered after 1 week of vitamin D withdrawal. We conclude that oral calcitriol pulse therapy is a good alternative for renal osteodystrophy in uraemic children. Careful monitoring of plasma parathyroid hormone and calcium is needed during follow-up when using this approach in paediatric patients.     

Unhealthy eating behaviour in adolescents

In recent years, eating disorders (Anorexia and Bulimia Nervosa) have increased and are appearing at increasingly younger ages. They affect predominantly adolescent females 12 to 25 years of age. The objective of this study of adolescents is to detect and discuss unhealthy eating behaviour, defined by either of two factors: (1) following a slimming diet not advised or supervised by any person trained in health care; or (2) eating very large quantities at irregular times, not related to anxiety or stress. A transversal study has been undertaken of 630 school children of 14–18 years of age (average: 15.9 years) in Cádiz (Andalucia, Spain), using an anonymous self-reporting questionnaire to collect data on personal and educational situation, on eating habits, on nutritive intake and knowledge of nutrition, and on dieting and physical exercise. The study has considered averages, ratios, statistical significance (x ²) and, as a measure of risk, the Disequality Ratio of Prevalence (DRP). Anomalous eating behaviour was detected in 46.3% (292), with females predominant by a ratio of 2:1. Comparing groups with anomalous and with normal eating habits, significant differences were detected in respect of: perception of body image (p<0.001), frequency of weighing oneself (p<0.05), periods of abstinence from eating (DRP 1.66; 95% confidence interval (CI): 1.66–2.37), provocation of vomiting (DRP 2.02; 95% CI: 1.13–3.65), use of laxatives (DRP 4.25; 95% CI: 1.08–9.63), and the exclusion of certain meals and types of food, mainly bread and cereals, fats and sugars. Conclusions are drawn on the substantial scale of unhealthy eating behaviour among adolescents in Cadiz. More adequate education on personal health and related social issues should be provided.     

Biomechanics and Classification of the Cartilaginous Structures to Project the Nasal Tip

The present paper is the long-term conclusion of our preliminary presentation at the 1992 ISAPS Congress (Guadalajara, Mexico). This is the result of 29 cadaver dissections of different ages and both sexes. We have observed that length, thickness, and resistance correlate with the possibility to project the nasal tip with the mere structure of the alar cartilage and its medial crurae. We also demonstrated the existence and antagonistic action of Pitanguy's ligament as well as the depressing ligament to project the nasal tip. In this study, besides focusing on classifying the medial crus according to its thickness, length, and resistance, which is already different from any previous classification, we also focused on its surgical utility, and its interaction with other anatomic elements, to achieve the desired projection. Clinically, we present a 12-year experience with 1653 cases operated under this premise.     

Imatinib inhibits proliferation of Ewing tumor cells mediated by the stem cell factor/KIT receptor pathway, and sensitizes cells to vincristine and doxorubicin-induced apoptosis.

PURPOSE AND EXPERIMENTAL DESIGN: The stem cell factor/KIT receptor loop may represent a novel target for molecular-based therapies of Ewing tumor. We analyzed the in vitro impact of KIT blockade by imatinib in Ewing tumor cell lines. RESULTS: KIT expression was detected in 4 of 4 Ewing tumor cell lines and in 49 of 110 patient samples (44.5%) by immunohistochemistry and/or Western blot analysis. KIT expression was stronger in Ewing tumors showing EWS-FLI1 nontype 1 fusions. Despite absence of c-kit mutations, constitutive and ligand-inducible phosphorylation of KIT was found in all tumor cell lines, indicating an active receptor. Treatment with KIT tyrosine kinase inhibitor imatinib (0.5-20 micro M) induced down-regulation of KIT phosphorylation and dose response inhibition of cell proliferation (IC(50), 12-15 micro M). However, imatinib administered alone at doses close to IC(50) for growth inhibition (10 micro M) did not induce a significant increase in apoptosis. We then analyzed if blockade of KIT loop through imatinib (10 micro M) was able to increase the antitumor in vitro effect of doxorubicin (DXR) and vincristine (VCR), drugs usually used in Ewing tumor treatment. Addition of imatinib decreased in 15-20 and 15-36% of the proliferative rate of Ewing tumor cells exposed to DXR and VCR, respectively, and increased in 15 and 30% of the apoptotic rate of Ewing tumor cells exposed to the same drugs. CONCLUSIONS: Inhibition of Ewing tumor cell proliferation by imatinib is mediated through blockade of KIT receptor signaling. Inhibition of KIT increases sensitivity of these cells to DXR and VCR. This study supports a potential role for imatinib in the treatment of Ewing tumor.