State Readout of a Trapped Ion Qubit Using a Trap-Integrated Superconducting Photon Detector.

We report high-fidelity state readout of a trapped ion qubit using a trap-integrated photon detector. We determine the hyperfine qubit state of a single ^{9}Be^{+} ion held in a surface-electrode rf ion trap by counting state-dependent ion fluorescence photons with a superconducting nanowire single-photon detector fabricated into the trap structure. The average readout fidelity is 0.9991(1), with a mean readout duration of 46 µs, and is limited by the polarization impurity of the readout laser beam and by off-resonant optical pumping. Because there are no intervening optical elements between the ion and the detector, we can use the ion fluorescence as a self-calibrated photon source to determine the detector quantum efficiency and its dependence on photon incidence angle and polarization.

Investigating staff knowledge of safeguarding and pressure ulcers in care homes.

OBJECTIVE: To investigate whether nursing/care home staff regard pressure ulceration as a safeguarding issue; and to explore reporting mechanisms for pressure ulcers (PUs) in nursing/care homes. METHOD: Within one clinical commissioning group, 65 staff members from 50 homes completed a questionnaire assessing their experiences of avoidable and unavoidable PUs, grading systems, and systems in place for referral to safeguarding teams. Understanding of safeguarding was assessed in depth by interviews with 11 staff members. RESULTS: Staff observed an average of 2.72 PUs in their workplaces over the previous 12 months, judging 45.6% to be avoidable. Only a minority of respondents reported knowledge of a grading system (mostly the EPUAP/NPUAP system). Most respondents would refer PUs to the safeguarding team: the existence of a grading system, or guidance, appeared to increase that likelihood. Safeguarding was considered a priority in most homes; interviewees were familiar with the term safeguarding, but some confusion over its meaning was apparent. Quality of written documentation and verbal communication received before residents returned from hospital was highlighted. However, respondents expressed concern over lack of information regarding skin integrity. Most staff had received education regarding ulcer prevention or wound management during training, but none reported post-registration training or formal education programmes; reliance was placed on advice of district nurses or tissue viability specialists. CONCLUSION: Staff within nursing/care homes understand the fundamentals of managing skin integrity and the importance of reporting skin damage; however, national education programmes are needed to develop knowledge and skills to promote patient health-related quality of life, and to reduce the health-care costs of pressure damage. Further research to investigate understanding, knowledge and skills of nursing/care home staff concerning pressure ulcer development and safeguarding will become increasingly necessary, as levels of the older population who may require assisted living continue to rise.

Standardisation of neonatal clinical practice.

The International Fetal and Newborn Growth Consortium for the 21(st) Century (INTERGROWTH-21(st) ) is a large-scale, population-based, multicentre project involving health institutions from eight geographically diverse countries, which aims to assess fetal, newborn and preterm growth under optimal conditions. Given the multicentre nature of the project and the expected number of preterm births, it is vital that all centres follow the same standardised clinical care protocols to assess and manage preterm infants, so as to ensure maximum validity of the resulting standards as indicators of growth and nutrition with minimal confounding. Moreover, it is well known that evidence-based clinical practice guidelines can reduce the delivery of inappropriate care and support the introduction of new knowledge into clinical practice. The INTERGROWTH-21(st) Neonatal Group produced an operations manual, which reflects the consensus reached by members of the group regarding standardised definitions of neonatal morbidities and the minimum standards of care to be provided by all centres taking part in the project. The operational definitions and summary management protocols were developed by consensus through a Delphi process based on systematic reviews of relevant guidelines and management protocols by authoritative bodies. This paper describes the process of developing the Basic Neonatal Care Manual, as well as the morbidity definitions and standardised neonatal care protocols applied across all the INTERGROWTH-21(st) participating centres. Finally, thoughts about implementation strategies are presented.

Probing the high momentum component of the deuteron at high Q2.

The (2)H(e,e'p)n cross section at a momentum transfer of 3.5 (GeV/c)(2) was measured over a kinematical range that made it possible to study this reaction for a set of fixed missing momenta as a function of the neutron recoil angle θ(nq) and to extract missing momentum distributions for fixed values of θ(nq) up to 0.55 GeV/c. In the region of 35°≤θ(nq)≤45° recent calculations, which predict that final-state interactions are small, agree reasonably well with the experimental data. Therefore, these experimental reduced cross sections provide direct access to the high momentum component of the deuteron momentum distribution in exclusive deuteron electrodisintegration.

Socio-economic and ethnic inequalities in diabetes retinal screening.

OBJECTIVE: We aimed to quantify socio-economic and ethnic inequalities in diabetes retinal screening. METHODS: Data were analysed for the retinal screening programme for three South London boroughs for the 18-month period to February 2009. Sight-threatening diabetic retinopathy (STDR) was defined as the occurrence of diabetic maculopathy, severe non-proliferative or proliferative diabetic retinopathy. Odds ratios were adjusted for sex, age group, duration and type of diabetes, self-reported ethnicity and deprivation quintile by participant postal code. RESULTS: There were 76 351 records obtained but, after excluding duplicate and ineligible records, data were analysed for 59 495 records from 31 484 subjects. There were 7026 (22%) subjects called for appointments who were not screened in the period, with 24 458 (78%) having one or more screening episodes. Non-attendance for screening was highest in young adults aged 18-34 years (32%) and in those aged 85 years or greater (28%). In the most deprived quintile, non-attendance was 23% compared with 21% in the least deprived quintile [odds ratio (OR) 1.37, 95% confidence interval (CI) 1.16-1.61, P < 0.001]. There were 2819 (11.5%) participants with STDR, including 10.8% in the least deprived quintile and 12.2% in the most deprived quintile (OR 1.10, 95% CI 0.95-1.16, P = 0.196). Compared with white Europeans (9.4%), STDR was higher in Africans (15.2%) and African Caribbeans (14.7%), resulting from a higher frequency of diabetic maculopathy. CONCLUSION: Socio-economic inequality in diabetes retinal screening may be smaller than reported in earlier studies. This study suggested an increased frequency of diabetic maculopathy among participants of African origins.

Scottish Stroke Research Network: the first three years.

Research networks were introduced in the UK to facilitate and improve clinical research and stroke was seen as a priority topic for local research network development. The Scottish Stroke Research Network (SSRN) is one of 11 stroke research networks in the UK. In this article we review the progress of the Scottish Stroke Research Network in the three years since inception. Between 2006-2009 the number of active hospital research sites has increased from 10 to 22 expanding to involve 20 stroke research nurses. There was a corresponding 58% increase in recruitment of participants into stroke studies, from 376 in 2006/07 to 594 in 2008/09. The majority (17/20) of our current studies are interventional. Data from one of these, the CLOTs trial (Clots in Legs Or sTocking after Stroke), demonstrates that the annual recruitment in Scotland increased from a median of 94 (range 6-122) patients per year in the six years before the SSRN, to 140 (135-158) patients per year after SSRN involvement. We currently screen about 50% of Scottish stroke patients and approximately 5% of Scottish stroke patients are participating in research studies that we support. The SSRN has made good progress in the first three years. Increasing the recruitment of screened patients remains a challenge.

Epithelial-mesenchymal interactions in prostatic development. II. Biochemical observations of prostatic induction by urogenital sinus mesenchyme in epithelium of the adult rodent urinary bladder.

Adult bladder epithelium (BLE) is induced to differentiate into glandular epithelium after association with urogenital sinus mesenchyme (UGM) and subsequent in vivo growth in syngeneic male hosts. Alteration of epithelial cytodifferentiation is associated with the expression of prostate-specific antigens, histochemical and steroid metabolic activities. These observations suggest that the inductive influence of the UGM has reprogrammed both the morphological and functional characteristics of the urothelium. In this report, differences regarding the mechanisms and effects of androgenic stimulation of prostate and bladder are exploited to determine the extent to which UGM plus BLE recombinants express a prostatelike, androgen-dependent phenotype. Results from cytosolic and autoradiographic binding studies suggest that androgen binding is induced in UGM plus BLE recombinants and that this activity is accounted for by the induced urothelial cells. In UGM plus BLE recombinants, androgen-induced [3H]thymidine or [35S]-methionine uptake analyzed by two-dimensional gel electrophoresis was qualitatively and quantitatively similar to that of prostate as opposed to bladder. These studies indicate that expression within BLE of prostatic phenotype is associated with a loss of urothelial characteristics and that androgen sensitivity is presumably a function of the inductive activities of the stroma.

A sodium channel signaling complex: modulation by associated receptor protein tyrosine phosphatase beta.

Voltage-gated sodium channels in brain neurons were found to associate with receptor protein tyrosine phosphatase beta (RPTPbeta) and its catalytically inactive, secreted isoform phosphacan, and this interaction was regulated during development. Both the extracellular domain and the intracellular catalytic domain of RPTPbeta interacted with sodium channels. Sodium channels were tyrosine phosphorylated and were modulated by the associated catalytic domains of RPTPbeta. Dephosphorylation slowed sodium channel inactivation, positively shifted its voltage dependence, and increased whole-cell sodium current. Our results define a sodium channel signaling complex containing RPTPbeta, which acts to regulate sodium channel modulation by tyrosine phosphorylation.

Skeletal muscle satellite cells.

Evidence now suggests that satellite cells constitute a class of myogenic cells that differ distinctly from other embryonic myoblasts. Satellite cells arise from somites and first appear as a distinct myoblast type well before birth. Satellite cells from different muscles cannot be functionally distinguished from one another and are able to provide nuclei to all fibers without regard to phenotype. Thus, it is difficult to ascribe any significant function to establishing or stabilizing fiber type, even during regeneration. Within a muscle, satellite cells exhibit marked heterogeneity with respect to their proliferative behavior. The satellite cell population on a fiber can be partitioned into those that function as stem cells and those which are readily available for fusion. Recent studies have shown that the cells are not simply spindle shaped, but are very diverse in their morphology and have multiple branches emanating from the poles of the cells. This finding is consistent with other studies indicating that the cells have the capacity for extensive migration within, and perhaps between, muscles. Complexity of cell shape usually reflects increased cytoplasmic volume and organelles including a well developed Golgi, and is usually associated with growing postnatal muscle or muscles undergoing some form of induced adaptive change or repair. The appearance of activated satellite cells suggests some function of the cells in the adaptive process through elaboration and secretion of a product. Significant advances have been made in determining the potential secretion products that satellite cells make. The manner in which satellite cell proliferative and fusion behavior is controlled has also been studied. There seems to be little doubt that cellcell coupling is not how satellite cells and myofibers communicate. Rather satellite cell regulation is through a number of potential growth factors that arise from a number of sources. Critical to the understanding of this form of control is to determine which of the many growth factors that can alter satellite cell behavior in vitro are at work in vivo. Little work has been done to determine what controls are at work after a regeneration response has been initiated. It seems likely that, after injury, growth factors are liberated through proteolytic activity and initiate an activation process whereby cells enter into a proliferative phase. After myofibers are formed, it also seems likely that satellite cell behavior is regulated through diffusible factors arising from the fibers rather than continuous control by circulating factors.(ABSTRACT TRUNCATED AT 400 WORDS)

Tumor-specific transplantation antigen(s) of bovine adenoviruses.

Protection against bovine adenovirus type 3-induced primary or transplantable tumors was studied in hamsters immunized with bovine adenoviruses, human adenovirus type 12 (A-12), simian adenovirus type 7 (SA7), or chicken-embryo-lethal-orphan (CELO) virus. Newborn hamsters inoculated with 2.3 times 10-5 plaqueforming units of bovine adenovirus type 3 were given injections of bovine serotypes 1, 2, or 3 during the latent period of tumor development. No hamsters immunized with type 3 and only 47% of those inoculated with types 1 or 2 developed tumors as compared to a control incidence of 90%. Primary tumors were not prevented when hamsters inoculated at birth with bovine adenovirus type 3 were immunized during the latent period with A-12, SA7, or CELO, even though 10-100 times more infectious virus was used. When adult hamsters were given injections of the bovine adenoviruses on 3 successive weeks and then challenged with graded doses of tumor cells, the three serotypes produced a 20-fold to 200-fold increase in the 50% tumor-producing dose of tumor cells. These studies indicate that bovine adenoviruses types 1, 2, and 3 induce cross-reactive transplantation antigens which, however, do not cross-react with those induced by oncogenic adenoviruses of either avian, simian, or human origin.

Virus-specific markers and virus-like particles in cell lines of tumors produced by CELO virus in Syrian golden hamsters.

Cell lines were established from 2 primary hepatocellular carcinomas (HC's) and 3 sarcomas produced in Syrian golden hamsters inoculated as newborns with chicken embryo lethal orphan (CELO) virus. Cell lines from 2 sarcomas (COT, CMT) and 1 HC (CEHEP) produced CELO virus-specific T-antigen. The antigen was not detected in cells of the third sarcoma line (RCT) until they had undergone more than 34 passages in vitro. Although 5-10% of cells in the second HC line (CILT/2) contained T-antigen during early passages, it was not demonstrable after the fifth subculture. Nevertheless, cells of both HC lines possessed CELO virus tumor-specific transplantation antigen. All 5 cell lines also contained hamster type R particles, and both HC lines had type C and intracytoplasmic type A particles. The percentage of carcinoma cells producing type R particles increased during cultivation in vitro, whereas the number of cells with type A particles decreased. Treatment with dibutyryl cyclic AMP and theophylline enhanced the number of cells producing type C particles in 1 HC line and type R particles in 2 sarcoma lines.

RNA type C virus antigens in hamster cells transformed by carcinogenic DNA viruses and chemicals.

The passive hemagglutination inhibition technique was used to test serologically for the presence of Syrian hamster type C virus antigen(s) (SHCVA) in a wide variety of normal and transformed hamster cells and tissues. SHCVA could not be detected in normal tissues or nonneoplastic tissues of tumor-bearing Syrian hamsters. Normal hamster embryo cells or cells transformed in vitro by simian adenovirus, by chemical alone, or doubly transformed by simian adenovirus and chemical did not contain SHCVA; however, SHCVA was found in a majority of tumors resulting from transplantation of these in vitro-transformed cells. No consistent pattern was observed in the capacity of individual transformed cell lines to produce SHCVA-positive or -negative tumors. When cells of a given transformed line were inoculated at 4 sites on each of 8 hamsters, SHCVA-positive tumors were found not to be randomly distributed but rather to be clustered on a few animals. SHCVA could be detected in only a few primary tumors induced by inoculation of carcinogenic DNA viruses; however, both the incidence and titer of SHCVA were significantly increased in a variety of transplanted tumors. These data suggest that SHCVA may be introduced into transplanted, transformed hamster cell tumors during passage in the host animal. Alternatively, in vivo conditions may allow expression of viral antigens not found under in vitro conditions; however, if this is true, only certain animals appear to be capable of activating SHCVA.

Potentiation of hamster tumors by normal cells or charcoal.

Admixed spleen cells from normal animals or from animals given injections of Syrian hamster type C virus significantly potentiated the growth of the transplanted D9 lymphoma of random-bred hamsters. Potentiation was measured by an increase in incidence of tumors, a shortened latent period, and a decreased 50% tumor-producing dose of tumor cells. Intermediate doses of spleen cells (10 to 100 spleen cells per tumor cell) produced the greatest potentiation. Preincubation of admixed spleen and tumor cell suspensions in vitro was unnecessary. Immunization to isoantigens was not responsible for potentiation, since growth of a transplantable carcinoma of inbred hamsters was also facilitated by normal spleen cells. In addition, normal kidney or liver cells increased the incidence of tumors transplanted by a small number of tumor cells. Potentiation did not occur when spleen cells were injected at a site remote from the tumor cells. Since the potentiating cells might act eigher as a physical barrier to host response, or by blocking normal macrophage function, we injected charcoal with tumor cells. Simultaneous treatment with charcoal facilitated the growth of the lymphoma but not that of the carcinoma. Treatment with some doses of charcoal was also effective at distant sites. Although potentiation of tumor growth by cells or charcoal may operate through different mechanisms, these phenomena should be explored in regard to outgrowth of primary tumors, tumor immunity, or enhancement of tumor growth.

"Hidden" cytotoxic antibodies that react with allogeneic cultured fetal and tumor cells contained in soluble immune complexes from normal human sera.

Hidden complement-dependent cytotoxins were demonstrated in normal donor sera after removing anti-immunoglobulins that normally block the ability of these immunoglobulin Gs to react with surface antigens on tumor cells. The blocking antibodies had certain properties of anti-idiotypes. Immunoglobulin G from Cohn Fraction II, after removing these anti-immunoglobulins, was cytotoxic for cultured fetal cells and for malignant melanoma, breast, lung, colon, and other tumor cells maintained either in tissue culture or by serial passage in nude mice. The cytotoxins were not adsorbed by extracts from normal lymphoid, liver, skin, or red blood cells. These results suggest that a heterogeneous group of natural antibodies reactive with antigens expressed on a variety of neoplastic and fetal cells circulate in normal donor sera as part of a soluble immune complex, together with a blocking anti-immunoglobulin.

Antitumor effects of alpha-interferon and gamma-interferon on a murine renal cancer (Renca) in vitro and in vivo.

Previous studies have shown that established murine renal cancer (Renca) can be successfully treated with the investigational drug flavone acetic acid (FAA) used in combination with recombinant interleukin 2 (IL-2). Additional experiments demonstrated that the in vivo administration of FAA rapidly induced the expression of the genes, as well as the biologically active proteins, for alpha- and beta-interferons (IFNs) as well as tumor necrosis factor alpha. Both IFN-alpha and IFN-gamma have been shown to have direct antiproliferative effects against some tumors, as well as being potent immunodulators for the induction of antitumor effector cells. Thus, the present study was designed to investigate the ability of IFN-alpha and/or IFN-gamma to mediate direct antiproliferative effects against Renca in vitro as well as to cause regression of Renca in vivo. The present study confirms that RAA and/or IL-2 are inactive against Renca in vitro, further suggesting an indirect mechanism for FAA-induced antitumor effects in vivo. However, the exposure of Renca in vitro to recombinant human IFN-alpha A/D, murine IFN-alpha or murine IFN-beta resulted in a dose dependent growth inhibition of Renca as assessed by the microculture tetrazolium dye incorporation assay. Very little growth inhibition was induced by recombinant murine IFN-gamma. Interestingly, IFN-alpha (100-1000 units/ml) when combined with very low doses of recombinant murine IFN-gamma (1-10 units/ml) yielded significantly more pronounced growth inhibition than either cytokine alone. This effect was most evident by 5 days of culture where combinations of 100-1000 units/ml recombinant human IFN-alpha A/D with 1-5 units/ml recombinant murine IFN-gamma yielded growth inhibition in the range of 45-99%. In order to determine whether the mechanisms for the antitumor activity of recombinant human IFN-alpha A/D and recombinant murine IFN-gamma was due to their direct antiproliferative effects, we also studied the efficacy of these combinations against i.p. Renca in athymic mice. In contrast to the potent antitumor effects observed in euthymic mice, the combination of IFN-alpha and IFN-gamma only slightly increased mean survival times in athymic mice and no long term survivors were obtained. Subsequent studies demonstrated that most mice (77%) cured of peritoneal Renca by recombinant human IFN-alpha A/D plus recombinant murine IFN-gamma were immune to rechallenge. Therefore the combination of IFN-alpha and IFN-gamma may directly inhibit the growth of Renca, but a major effect of IFNs in vivo must be to contribute to the induction of an anti-Renca immune response.

Selective stimulation of in situ intermediary metabolism by free calcium in permeabilized rat adipocytes.

The hypothesis that ionized calcium [Ca2+]i may stimulate in situ rat adipocyte intermediary metabolism distal to glucose transport was tested. A metabolically active porous adipocyte model was employed in which pathway metabolism is exclusively pore-dependent using glucose 6-phosphate (G6P) as substrate. Cellular [Ca2+]i was, furthermore, directly adjusted to between 0-2.5 microM via the membrane pores. Three metabolic fluxes were examined, (1) glycolysis-Krebs ([6-14C]G6P oxidation), (2) glycolysis to lactate ([U-14C]G6P to [14C]lactate) and (3) pentose pathway ([1-14C]G6P oxidation). Glycolysis-Krebs oxidation was was found to be selectively (33% above basal P less than 0.001) stimulated by 0.625 microM free calcium. In contrast, there was no effect of [Ca2+]i on the other, exclusively cytoplasmic, pathways. The stimulation of glycolysis-Krebs by [Ca2+]i was inhibited by a mitochondrial calcium channel blocker (Ruthenium red) and persisted over a range of ATP/ADP ratios. Separate studies demonstrated that 2-[1-14C]ketoglutarate oxidation was also calcium-stimulated in the porous adipocytes (160% over baseline at 1 microM [Ca2+]i). These studies thus demonstrate that physiologically relevant increments in porous adipocyte [Ca2+]i enhance overall in situ glycolytic-Krebs pathway oxidation by a mechanism which entails mitochondrial calcium uptake. Methodologically, this metabolically active porous adipocyte model presents a novel experimental approach to investigations regarding the effects of ionized calcium on intermediary metabolism beyond glucose transport.

Inhibition of leptin secretion by insulin and metformin in cultured rat adipose tissue.

Leptin's role in the regulation of food intake, energy expenditure and weight control are widely recognized, especially in rodents. Likewise, the potential regulation of leptin secretion by insulin (and vice versa) has been of particular interest insofar as these nutrient signals may have meaningful, even adverse (inter)actions, in diabetes. We used a freshly isolated rat adipose tissue culture model to examine the effect of insulin, metformin and glibenclamide on basal and steroid-stimulated leptin secretion. This model was selected because of its physiologic rates of leptin formation and preservation of potentially significant cell-cell interactions compared to isolated cells. The basal rate of leptin secretion was 3. 4+/-1.2 ng/100 mg tissue/24 h. The addition of 100 nM dexamethasone or 400 nM hydrocortisone stimulated leptin secretion by 3-4 fold over basal (no steroid). Insulin inhibited both basal and steroid-activated leptin secretion by 35-50%. This inhibition was present with either 1 mM pyruvate or 5 mM glucose as a substrate suggesting that glycolysis was not required. Metformin inhibited basal and dexamethasone-stimulated leptin secretion in a dose dependent manner (50% inhibition occurred at 1 mM metformin) while glibenclamide was ineffective. The effect of insulin on isolated fat cells versus fat tissue was tested in parallel. After 24 h in culture, insulin inhibited leptin secretion similarly in both adipose preparations. The addition of 200 nM (-)N6-(2-phenylisopropyl)-adenosine did not alter the results.

Persistence of disturbed adipocyte metabolism in streptozocin-induced diabetic rats despite near-euglycemia with phlorizin.

It is widely accepted that hyperglycemia per se incites and perpetuates the diabetic state by adverse effects on beta cell insulin secretion and peripheral insulin action. Examination of the latter locus has revealed glucose-related abnormalities in facilitated glucose transport. Beyond the plasma membrane, however, there is scant data examining whether hyperglycemia influences important intracellular metabolic events. We recently described a sizable reduction in post-transport, in situ metabolism in permeabilized fat cells from streptozocin-induced diabetic rats. Of importance, the diabetes-related deficit was entirely ameliorated by insulin therapy. In this study we examined whether hyperglycemia per se contributes to this altered intracellular metabolic effect. By infusing phlorizin, near euglycemia was achieved for at least four days in streptozocin-induced diabetic rats. The phlorizin-treated diabetic rats had improved (intact cell) rates of insulin-stimulated 2-deoxyglucose uptake. Despite this, permeabilized fat cell studies revealed no improvement or deterioration in diabetic intracellular metabolism as measured by both the oxidation of [6-14C]glucose-6-phosphate via the citric acid cycle or its incorporation into triglyceride. We conclude that hypoinsulinemia, and not hyperglycemia, mediates the disturbance in porous diabetic adipocyte cellular metabolism.

Activation of in situ glycolytic flux by bisphosphorylated compounds: studies in porous rat adipocytes.

By carefully permeabilizing eukaryotic cells such that intracellular enzymes are largely retained, an opportunity is created to explore the regulation of in situ flux. This is particularly important since the latter may not be accurately represented by kinetic measurements of isolated, solubilized enzymes from disrupted cells. In this study the action of fructose 2,6-diphosphate (F2,6DP) and other bisphosphorylated sugars which purportedly activate phosphofructokinase-1 (PFK-1; EC 2.7.1.11) were studied. Using porous adipocytcs and initiating flux with radiolabeled glucose 6-phosphate, the regulation of lactate production under both 0.1 and 1.0 mM ATP conditions by F2,6DP, glucose 1,6-diphosphate (G1,6DP), ribulose 1,5-diphosphate (R1,5DP), 2,3 diphosphoglycerate (2,3DPG), and mannose 6-phosphate (M6P) was examined. Studied at 1, 5, and 25 microM concentrations, F2,6DP and 2,3DPG significantly (and to the same extent) augmented glycolysis compared to control (at 0.1 mM ATP, the respective glycolytic rates--as % above control--at these three above-mentioned concentrations for F2,6DP were 60, 84, and 77%, whereas for 2,3DPG they were 84, 105, and 179%; at 1 mM ATP, the F2,6DP effect was 88, 99, and 121%, and for 2,3DPG it was 52, 89, and 96%). Stimulation by these compounds was less obvious at higher glycolytic flux rates (saturating amounts of G6P). Amongst this group, and only at 1.0 mM ATP, the sole other positive effector was 25 microM R1,5DP. The measured fat cell content of G1,6DP was 24 +/- 4 microM (n = 3); at this concentration no significant effect on glycolysis was observed. Examining the effects of 2,3DPG (25 microM) on proximal glycolysis (to triose phosphates) revealed there was a modest, but significant, 41% increase over basal; in contrast, under the exact same conditions, F2,6DP caused a 123% increase. Separate experiments also examined the effect of F2,6DP, 2,3DPG, and G1,6DP on glycolysis at 5 and 25 microM in the presence of a physiologic cytosolic ATP/ADP ratio and free cation concentrations. Under these conditions, F2,6DP and 2,3DPG remained pre-eminent in their stimulatory prowess, inducing 27-71% increases over control, while G1,6DP remained ineffectual. These studies support a locus of action of 2,3DPG on overall glycolysis which is distal to the triose phosphates. M6P was ineffective at all concentrations. In conclusion, F2,6DP is the pre-eminent in situ regulator of in situ adipocyte glycolysis, especially at higher ATP levels, although other sugars containing two phosphoryl groups may under certain conditions cause activation.