Purified murine hematopoietic stem cells function longer on nonirradiated W41/Wv than on +/+ irradiated stroma

Mouse bone marrow (BM) was separated into low-density, lineage- negative, wheat germ agglutinin-positive (WGA+), Rhodamine-123 bright (Rhbright) or dim (Rhdim) cells to obtain populations that were highly enriched for committed progenitors (Rhbright cells) or for more primitive stem cells (Rhdim). When 2,500 Rhbright or Rhdim cells were seeded onto 6-week-old irradiated (20 Gy) long-term BM cultures (LTBMC), the nonadherent cell production from Rhbright cells was transient and ended after 5 weeks. Production from Rhdim cells did not begin until week 3, peaked at week 5, and ended at week 8, when the irradiated stroma seemed to fail. Termination of cell production from Rhdim cells did not occur in nonirradiated LTBMC from W41/Wv mice. During peak nonadherent cell production, 25% to 30% of the cells in the nonirradiated LTBMC from W41/Wv mice had donor cell markers. Two approaches were tested to try to enhance the proportion or number of donor cells. Addition of Origen-HGF at the time of seeding Rhdim cells caused a nonspecific increase in both host and donor cell production, but a specific increase in production of donor cells was obtained by seeding the cultures at 2 weeks rather than 6 weeks. Limiting dilution of Rhdim cells gave the same frequency of wells producing cells on both irradiated +/+ and nonirradiated W41/Wv or W/Wv cultures.     

Detection of dimeric inhibin throughout the human menstrual cycle by two-site enzyme immunoassay

OBJECTIVE We have developed and validated a two-site immunoassay for the measurement of dimeric inhibin in plasma and subsequently measured dimeric inhibin levels in plasma through the normal female menstrual cycle. DESIGN Recombinant inhibin added to plasma samples was quantitatively recovered in both follicular and luteal phase, and serial dilutions of samples were tested for parallelism to similar dilutions of recombinant 32kDa inhibin. Daily samples were assayed from four women through a menstrual cycle. PATIENTS (a) Four groups of six women who (i) were in the follicular phase of a normal menstrual cycle, (ii) were in the luteal phase of a normal menstrual cycle, (iii) were post-menopausal and (iV) who had received hMG to induce superovulation. (b) Four healthy female volunteers aged 25–33. RESULTS Post-menopausal women had less than 2ng/l of inhibin whereas six women treated with hMG had dimeric inhibin concentrations up to 1125ng/l. During the early follicular phase, at the time of onset of menstruation, extremely low levels of dimeric inhibin were found (3-4ng/l (CI 2.2-5.0)) while in the late follicular phase, there was a marked increase in dimeric inhibin concentration. The concentration of dimeric inhibin was maximal (65.6 ng/l (CI 53.1-81,1)) in the mid-luteal phase. The overall pattern of dimeric inhibin concentration during the menstrual cycle was similar to that observed with previous inhibin assays although the magnitude of change was considerably greater. CONCLUSION The human ovary, In particular the corpus luteum, secretes significant amounts of dimeric and therefore biologically active inhibin.     

Antibodies against oxidized low-density lipoproteins in systemic sclerosis

OBJECTIVE: To investigate whether circulating concentrations of antibodies against oxidized low-density lipoproteins (LDL) are increased in patients with systemic sclerosis (SSc). METHODS: Oxidation of LDL and anti-oxidized LDL antibodies were measured in 26 patients with limited cutaneous SSc (LCSSc), in eight patients with diffuse cutaneous SSc (DCSSc) and in 24 healthy control subjects. Results were adjusted for age, sex and smoking. RESULTS: Binding to oxidized LDL was increased in patients with both limited and diffuse cutaneous disease (geometric mean 0.35 and 0.39 optical density units respectively) compared with controls (0.28) (P=0.03 and P=0.01 respectively). Circulating concentrations of anti-oxidized LDL were increased only in patients with diffuse SSc (geometric mean 0.22 optical density units) compared with controls (geometric mean 0.16, P=0.02). CONCLUSION: These preliminary findings lend further weight to the concept that oxidation of LDL contributes to the vascular pathology of SSc, particularly in patients with diffuse cutaneous disease. Prospective longitudinal studies are required to investigate whether anti-oxidized LDL antibodies may be a marker of vascular damage in SSC.     

Plasma TGF beta in systemic sclerosis: a cross-sectional study.

OBJECTIVES--To determine whether the active 25 kDa form of the fibrogenic cytokine transforming growth factor beta (TGF beta) can be detected in plasma from patients with systemic sclerosis and to examine the relationship between plasma TGF beta and clinical markers of disease severity and serum concentrations of the aminoterminal peptide of type III procollagen (PIIINP) (a laboratory marker of the fibrotic process). METHODS--A cross sectional study was made of 39 patients with systemic sclerosis (11 diffuse and 28 limited), nine patients with primary Raynaud's disease and 60 healthy controls. TGF beta 1 and TGF beta 2 were measured by enzyme linked immunosorbent assay (ELISA) (sensitivity 100 pg/ml) and PIIINP by radioimmunoassay. RESULTS--TGF beta 1 was detected in plasma from six of 39 patients with systemic sclerosis but not in any patient with primary Raynaud's disease or healthy controls. TGF beta 2 was not detected in plasma from patients or controls. No clear relationship was demonstrated between TGF beta 1, clinical features or PIIINP concentrations. CONCLUSIONS--The 25 kDa form of TGF beta 1 can be detected in the plasma of some patients with systemic sclerosis. This provides limited support for the hypothesis that this cytokine plays a role in the pathogenesis of this disease. However, longitudinal studies, particularly in early diffuse disease, are required to clarify the relationship between circulating TGF beta 1 and disease activity.     

Tolerance of Larger Body Sizes by Young Adults Living in Australia and Hawaii

Identifying the barriers to achieving an appropriate body size is important for health. This study investigated young adults' tolerance of excess weight in other adults. Participants were 172 students (65 male, 107 female) with a mean age of 22.24 years (SD = 1.61). Half the participants resided in Australia, and half in Hawaii. Students from both countries were found to be tolerant of body sizes larger than those recommended for good health. These results help inform our understanding of the factors that may influence weight gain, and have important implications for the worldwide obesity problem and related health issues.     

[11C]5-HTP and microPET are not suitable for pharmacodynamic studies in the rodent brain

The PET tracer [¹¹C]5-hydroxytryptophan ([¹¹C]5-HTP), which is converted to [¹¹C]5-hydroxytryptamine ([¹¹C]5-HT) by aromatic amino acid decarboxylase (AADC), is thought to measure 5-HT synthesis rates. But can we measure these synthesis rates by kinetic modeling of [¹¹C]5-HTP in rat? Male rats were scanned with [¹¹C]5-HTP (60 minutes) after different treatments. Scans included arterial blood sampling and metabolite analysis. 5-HT synthesis rates were calculated by a two-tissue compartment model (2TCM) with irreversible tracer trapping or Patlak analysis. Carbidopa (inhibitor peripheral AADC) dose-dependently increased [¹¹C]5-HTP brain uptake, but did not influence 2TCM parameters. Therefore, 10 mg/kg carbidopa was applied in all subsequent study groups. These groups included treatment with NSD 1015 (general AADC inhibitor) or p-chlorophenylalanine (PCPA, inhibitor of tryptophan hydroxylase, TPH). In addition, the effect of a low-tryptophan (Trp) diet was investigated. NSD 1015 or Trp depletion did not affect any model parameters, but PCPA reduced [¹¹C]5-HTP uptake, and the k₃. This was unexpected as NSD 1015 directly inhibits the enzyme converting [¹¹C]5-HTP to [¹¹C]5-HT, suggesting that trapping of radioactivity does not distinguish between parent tracer and its metabolites. As different results have been acquired in monkeys and humans, [¹¹C]5-HTP-PET may be suitable for measuring 5-HT synthesis in primates, but not in rodents.