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Biomedical subjects

D Elmore

Publications and source records attributed to D Elmore.

14 recordsLinked to original sources
PubMed2006

Soy isoflavones do not affect bone resorption in postmenopausal women: a dose-response study using a novel approach with 41Ca.

INTRODUCTION: The purpose of this 3-way crossover study was to identify the effective dose of soy protein isolate enriched with isoflavones for suppressing bone resorption in postmenopausal women using a novel, rapid assessment of antibone resorbing treatments. METHODS: Thirteen postmenopausal women (>or=6 yr since menopause) were predosed with 41Ca iv. After a 200-d baseline period, subjects were given 43 g soy protein/d that contained 0, 97.5, or 135.5 mg total isoflavones in randomized order. The soy protein isolate powder was incorporated into baked products and beverages. Each 50-d intervention phase was preceded by a 50-d pretreatment phase for comparison. Serum isoflavone levels and biochemical markers were measured at the end of each phase. Twenty-four-hour urine samples were collected approximately every 10 d during each phase for 41Ca/Ca analysis by accelerator mass spectrometry. RESULTS: Serum isoflavone levels reflected the amount of isoflavones consumed in a dose-dependent manner. None of the isoflavone levels had a significant effect on biochemical markers of bone turnover, urinary cross-linked N teleopeptides of type I collagen and serum osteocalcin, or bone turnover as assessed by urinary 41Ca/Ca ratios. CONCLUSIONS: Soy protein with isoflavone doses of up to 135.5 mg/d did not suppress bone resorption in postmenopausal women. This is the first efficacy trial using the novel technique of urinary 41Ca excretion from prelabeled bone.

Adult↗
PubMed2001

New experimental limits on strongly interacting massive particles at the TeV scale.

We have carried out a search for strongly interacting massive particles (SIMPs) bound to Au and Fe nuclei, which could manifest themselves as anomalously heavy isotopes of these elements. Our samples included gold from the NASA Long Duration Exposure Facility satellite, RHIC at Brookhaven National Laboratory, and from various geological sources. We find no evidence for SIMPs in any of our samples, and our results set stringent limits (as low as approximately 10(-12)) on the abundances of anomalous Au or Fe isotopes with masses up to 1.67 and 0.65 TeV/c(2), respectively.

Journal Article↗
PubMed2001

Aluminum bioavailability from drinking water is very low and is not appreciably influenced by stomach contents or water hardness.

The objectives were to estimate aluminum (Al) oral bioavailability under conditions that model its consumption in drinking water, and to test the hypotheses that stomach contents and co-administration of the major components of hard water affect Al absorption. Rats received intragastric 26Al in the absence and presence of food in the stomach and with or without concomitant calcium (Ca) and magnesium (Mg) at concentrations found in hard drinking water. The use of 26Al enables the study of Al pharmacokinetics at physiological Al concentrations without interference from 27Al in the environment or the subject. 27Al was intravenously administered throughout the study. Repeated blood withdrawal enabled determination of oral 26Al bioavailability from the area under its serum concentrationxtime curve compared to serum 27Al concentration in relation to its infusion rate. Oral Al bioavailability averaged 0.28%. The presence of food in the stomach and Ca and Mg in the water that contained the orally dosed 26Al appeared to delay but not significantly alter the extent of 26Al absorption. The present and published results suggest oral bioavailability of Al from drinking water is very low, about 0.3%. The present results suggest it is independent of stomach contents and water hardness.

Administration, Oral↗
PubMed2001

In vivo degradation of 14C-labeled small intestinal submucosa (SIS) when used for urinary bladder repair.

The rate of in vivo degradation was determined for a naturally occurring biomaterial derived from the extracellular matrix of the small intestinal submucosa (SIS). The SIS was labeled by giving weekly intravenous injections of 10 microCi of 14C-proline to piglets from 3 weeks of age until the time of sacrifice at 26 weeks. The resultant SIS prepared from these pigs contained approximately 10(3) fold more 14C than unlabeled tissues. The labeled SIS was used to repair experimental defects in the urinary bladder of 10 dogs. The animals were sacrificed at post-operative times ranging from 3 days to 1 year and the remodeled urinary bladder tissue was harvested for evaluation of 14C by a combination of liquid scintillation counting and accelerator mass spectrometry. The remodeled tissue contained less than 10% of the 14C (disintegrations per minute/gram tissue wet weight) at 3 months post-surgery compared to the SIS biomaterial that was originally implanted. The SIS scaffold was replaced by host tissue that resembled normal bladder both in structure and function. After implantation, 14C was detected in highest concentrations in the blood and the urine. The SIS bioscaffold provides a temporary scaffold for tissue remodeling with rapid host tissue remodeling, degradation, and elimination via the urine when used as a urinary bladder repair device.

Animals↗
PubMed2001

A preliminary study of the dermal absorption of aluminium from antiperspirants using aluminium-26.

Aluminium chlorohydrate (ACH), the active ingredient in many antiperspirants, was labeled with the radioisotope 26Al. The labeled ACH was then fractionated into about 100 samples using gel filtration chromatography. Each fraction was analyzed for 26Al and total aluminium content. Aluminium-26 was only detected in the fractions that also contained aluminium, which verified that the ACH was uniformly labeled. 84 mg of the labeled ACH was then applied to a single underarm of two adult subjects with blood and urine samples being collected over 7 weeks. Tape-stripping and mild washings of the skin were also collected for the first 6 days. Results indicate that only 0.012% of the applied aluminium was absorbed through the skin. At this rate, about 4 microg of aluminium is absorbed from a single use of ACH on both underarms. This is about 2.5% of the aluminium typically absorbed by the gut from food over the same time period. Therefore, a one-time use of ACH applied to the skin is not a significant contribution to the body burden of aluminium.

Administration, Topical↗
PubMed2001

Entry, half-life, and desferrioxamine-accelerated clearance of brain aluminum after a single (26)Al exposure.

The objectives of our study were to estimate the percentage of aluminum (Al) that enters the brain, the half-life of brain Al, and the ability of an Al chelator to reduce brain Al. Rats received an iv infusion of Al transferrin, the primary Al species in plasma, or Al citrate, the predominant small molecular weight Al species in plasma. The infusion contained approximately 0.2-0.3 nCi (0.4-0.6 nmol) (26)Al, enabling the study of Al distribution into and retention by the brain at physiological Al concentrations. Some Al transferrin-infused rats received ip injections of the Al chelator desferrioxamine (DFO), 0.15 mmol/kg, three times weekly. The others received saline injections. The rats were euthanized from 4 hr to 4 days (Al citrate) or 256 days (Al transferrin) later. Brain (26)Al was determined by accelerator mass spectrometry. Peak brain (26)Al concentration was approximately 0.005% of the (26)Al dose in each gram of brain, irrespective of Al species administered. In the absence of DFO treatments, brain (26)Al concentration decreased with a half-life of approximately 150 days. The brain Al half-life in the DFO-treated rats was approximately 55 days. The results show a small fraction of Al in blood enters the brain, where it persists for a long time. The ability of repeated DFO treatments to modestly accelerate the reduction of brain Al is consistent with the necessity of prolonged DFO therapy to significantly reduce Al-induced dialysis encephalopathy.

Aluminum↗
PubMed2000

New experimental test of the pauli exclusion principle using accelerator mass spectrometry

We report the results of a new experimental search for the Pauli-forbidden 1s(4) state of Be, denoted by Be ('). Using the Accelerator Mass Spectrometer facility at Purdue University, we set limits on the abundance of Be (') in metallic Be, Be ore, natural gas, and air. Our results improve on those obtained in a previous search for Be (') by a factor of approximately 300.

Journal Article↗
PubMed2000

Direct measurement of aluminum uptake and distribution in single cells of Chara corallina.

Quantitative information on the uptake and distribution of Al at the cellular level is required to understand mechanisms of Al toxicity, but direct measurement of uptake across the plasma membrane has remained elusive. We measured rates of Al transport across membranes in single cells of Chara corallina using the rare (26)Al isotope, an emerging technology (accelerator mass spectrometry), and a surgical technique for isolating subcellular compartments. Accumulation of Al in the cell wall dominated total uptake (71-318 microgram m(-2) min(-1)), although transport across the plasma membrane was detectable (71-540 ng m(-2) min(-1)) within 30 min of exposure. Transport across the tonoplast was initially negligible, but accelerated to rates approximating uptake across the plasma membrane. The avacuolate protoplasm showed signs of saturation after 60 min, but continued movement across the plasma membrane was supported by sequestration in the vacuole. Saturation of all compartments was observed after 12 to 24 h. Accumulation of Al in the cell wall reflected variation in [Al(3+)] induced by changes in Al supply or complexing ligands, but was unaffected by pH. In contrast, transport across the plasma membrane peaked at pH 4.3 and increased when [Al(3+)] was reduced by complexing ligands. Cold temperature (4 degrees C) reduced accumulation in the cell wall and protoplasm, whereas 2,4-dinitrophenol and m-chlorocarbonylcyanidephenyl hydrazone increased membrane transport by 12- to 13-fold. Our data suggest that the cell wall is the major site of Al accumulation. Nonetheless, membrane transport occurs within minutes of exposure and is supported by subsequent sequestration in the vacuole. The rapid delivery of Al to the protoplasm suggests that intracellular lesions may be possible.

2,4-Dinitrophenol↗
PubMed1997

Dendrite cell-T cell mixtures, isolated from the skin and mucosae of macaques, support the replication of SIV.

Previous studies have shown that HIV-1 exploits dendritic cells (DCs) to replicate and spread among CD4+ T cells. The DCs within mucosal surfaces may be especially important, but these are more difficult to access. To study more extensively the properties of DCs and other leukocytes from skin and different mucosae, DCs were isolated from uninfected macaques and their sensitivity assessed to infection with SIV in vitro. Dendritic cells and T cells readily emigrated from organ cultures of macaque skin, as described previously for humans. In addition, characteristic cells emigrated from explants of mucosae, both nasopharyngeal (adenoid and tonsil) and genital (vagina and cervix). The macaque DCs reacted with the monoclonals that are used to study human DCs, such as MAbs to CD40, CD86, CD83, and the p55 protein. When SIV was added to the DC-T cell mixtures from these different organs, extensive replication was observed in all but the cervical leukocytes. SIV replication occurred without the use mitogens, and with virus that had been grown in a cell line in the absence of mitogens and IL-2. Most of the newly synthesized viral protein is observed in syncytia. Therefore, mixtures of DCs and T cells isolated from mucosal surfaces served as a naturally permissive environment for SIV replication.

Animals↗
PubMed1997

Cutaneous dendritic cells promote replication of immunodeficiency viruses.

The cutaneous or mucosal DC-T cell environments seem extremely supportive of immunodeficiency virus replication. Apart from very early after SIV infection, similar virus producing cells have been difficult to detect in the lymphoid tissues where DCs and T cells are also known to interact. Large amounts of virus can be visualized in the germinal centers of the lymph nodes, much of which represents immune complexed virus that is trapped on the follicular dendritic cell surface. However, whether these virus-carrying cells actually make virus or even virus proteins requires further investigation. We believe that once an individual is systemically infected, free virus and/or virus-infected cells will seed peripheral tissues and when encountering similar DC-T cell environments as described in the oral mucosae, can set up sites of chronic virus replication. For instance, a virus-carrying T cell that migrates to the periphery would, on entering this milieu, interact with the mature DCs and activate virus production. This likely occurs at similar sites around the body, such as the mucosal associated lymphoid tissue of the gut, and is probably independent of the route of infection.

Animals↗
PubMed1997

Aluminum (26AI) metabolism in rats.

Because of the lack of a suitable isotope and a sensitive technique of analysis, aluminum has been studied indirectly using analogs such as 67Ga (t1/2 = 78 hr). Recently, with the development of accelerator mass spectrometry (AMS), it has become possible to use the artificially produced radionuclide of aluminum, aluminum 26 (26AI), (t1/2 = 7.16 x 10(5) years). AMS is used for measuring long-lived and stable isotopes with the sensitivity of an attomole (10(-17) mol). To study aluminum metabolism, 26AlCl3 was administered to rats intraperitoneally (ip) by injection and orally by gavage (n = 3/group). Blood was collected periodically. On Day 8 following perfusion, blood, liver, kidney, femur, brain, and spleen were collected and analyzed for 26AI. Of all the tissues studied, 26AI accumulation was greatest in the bone. 26AI accumulated in tissues as: bone > spleen > kidney approximately liver > brain, but absorption was low (0.97% of dose). AMS offers great potential in AI research as it is the only technique available for tracer aluminum study.

Absorption↗
PubMedDate not supplied

In vivo absorption of aluminium-containing vaccine adjuvants using 26Al.

Aluminium hydroxide (AH) and aluminium phosphate (AP) adjuvants, labelled with 26Al, were injected intramuscularly (i.m.) in New Zealand White rabbits. Blood and urine samples were collected for 28 days and analysed for 26Al using accelerator mass spectrometry to determine the absorption and elimination of AH and AP adjuvants. 26Al was present in the first blood sample (1 h) for both adjuvants. The area under the blood level curve for 28 days indicates that three times more aluminium was absorbed from AP adjuvant than AH adjuvant. The distribution profile of aluminium to tissues was the same for both adjuvants (kidney > spleen > liver > heart > lymph node > brain). This study has demonstrated that in vivo mechanisms are available to eliminate aluminium-containing adjuvants after i.m. administration. In addition, the pharmacokinetic profiles of AH and AP adjuvants are different.

Absorption↗