The stain removal performance of a new anti-hypersensitivity dentifrice.

OBJECTIVE: To investigate the stain removal potential in vitro of a new anti-hypersensitivity dentifrice. The dentifrice contains a low level of abrasive, the zwitterionic surfactant cocamidopropyl betaine, and potassium nitrate. It has been developed to be as gentle as possible to tooth surfaces and oral soft tissues, while effectively treating dentinal hypersensitivity. METHODOLOGY: The Relative Dentine Abrasivity (RDA) method was used to measure abrasivity. The Pellicle Cleaning Ratio (PCR) and the Natural Extrinsic Stain Removal (NESR) methods were used to test stain removal performance against suitable controls. RESULTS: The RDA value for the formulation was 34 +/- 2 (Mean +/- S.E.). The PCR value was 46 +/- 4, comparable with Elmex Sensitive. The NESR test, which has previously been shown to give better clinical correlation than the PCR, demonstrated that the new formulation gave superior stain removal performance compared with both Sensodyne MultiCare and a conventional nonsensitivity formulation, and similar stain removal performance to Elmex Sensitive. CONCLUSION: The new formulation has been shown, in these studies, to combine low abrasivity with an in vitro stain removal performance comparable with that of benchmark marketed pastes.

Frequency dependent hysteresis of silicone and latex mock arteries used in stent testing.

Mock arteries also called as mock vessels are one of the best alternatives available to researchers in evaluating the mechanical characteristics and durability of intravascular medical products without having to use animal and human clinical studies. The behavior of mock arteries depends on the frequency of loading. This makes it essential to evaluate and analyze the compliance and hysteresis of the mock arteries at different frequencies. Hysteresis, the difference in the pressure-volume curve between the loading cycle and the unloading cycle, plays an important role in determining the mechanical properties of the mock arteries. Six each of silicone and latex mock arteries were tested for this study. Three silicone and three latex mock arteries were tested at room temperature for dynamic internal compliance, and the remaining three each of silicone and latex mock arteries were soaked in distilled water at 37 degrees C for 36 hours and then compliance tested using a dynamic compliance tester. All arteries were tested at four different frequencies: 72, 500, 1000, and 1500 beats per minute.

Human Mast cell progenitors can be infected by macrophagetropic human immunodeficiency virus type 1 and retain virus with maturation in vitro.

Mast cells are critical components of innate and adaptive immunity that differentiate in tissues in situ from circulating committed progenitor cells. We now demonstrate that human cord blood-derived mast cell progenitors are susceptible to infection with macrophagetropic (M-tropic) and dualtropic human immunodeficiency virus type 1 (HIV-1) isolates but not with T-cell-tropic (T-tropic) strains. Mast cell progenitors (c-kit(+) CD13(+) cells with chloroacetate esterase activity) were purified from 4-week-old cultures of cord blood mononuclear cells maintained in stem cell factor, interleukin-6 (IL-6), and IL-10 using a CD14 depletion column. These progenitors expressed CCR3, CCR5, and CXCR4, as well as low levels of CD4. When infected in vitro with viruses pseudotyped with different HIV and simian immunodeficiency virus envelope glycoproteins, only M-tropic and dualtropic, but not T-tropic, viruses were able to enter mast cell progenitors. Both the CCR5-specific monoclonal antibody 2D7 and TAK-779, a nonpeptide inhibitor of CCR5-mediated viral entry, blocked HIV-1 strain ADA infection by >80%. Cultures infected with replication-competent virus produced progressively increasing amounts of virus for 21 days as indicated by p24 antigen detection. Mast cell progenitors that were exposed to an M-tropic, green fluorescent protein-expressing HIV-1 strain exhibited fluorescence indicative of viral entry and replication on a single-cell level and retained virus production during differentiation. The trafficking of mast cell progenitors to multiple tissues, combined with the long life span of mature mast cells, suggests that they could provide a widespread and persistent HIV reservoir in AIDS.

The durability of silicone versus latex mock arteries.

Latex mock arteries used in medical device testing allow researchers to evaluate mechanical characteristics of intravascular medical products without using animal or human clinical studies for this data. Such intravascular situations include determining properties such as drag and steerability of catheters, recoil of vascular stents, and clinician training. In fatigue testing, the latex mock arteries are used to receive deployed products and are then repeatedly pressurized at biologically relevant pressures to determine the long term durability of the product. By matching dimensions and pressure-volume relationships (compliance) of these latex tubes, researchers have a reliable means to evaluate and predict product lifetimes. The problem with latex mock arteries is two-fold: First, they are opaque so the product inside the artery cannot be seen during evaluation of the integrity of the product or during clinical training sessions. Second, latex tubes fatigue; therefore, the loading that they place on the internalized products varies with time. During long term durability studies, latex tubes may have to be replaced as often as every 100 million cycles. This can be problematic with products that are difficult to redeploy. We have developed a clear silicone mock artery system that allows us to fabricate three-dimensional objects, including tubes with precise geometric and mechanical properties. Our evaluations show that the mock arteries can be stressed up to 400 million cycles with little or no change in mechanical properties. We are in the process of continuing evaluations to determine long term durability.

The high frequency testing of vascular grafts and vascular stents: influence of sample dimensions on maximum allowable frequency.

There are over four dozen companies developing new products for the lucrative vascular graft and vascular stent markets. We have been studying the procedures used to pre-test vascular grafts, vascular stents, and mock arteries into which vascular stents are placed, so that appropriate high frequency durability/fatigue studies can be done in as short a time as possible, but also in a manner in which the data are highly reliable and dependable. In the past, we have evaluated the testing of the natural frequency response of the grafts, mock arteries, and stents in order to determine the frequencies that can be used for long-term life testing. In this paper, we present experiments that evaluate how product geometry affects product frequency response at various loading pressures. Results show that changing the dimensions of the device to be tested such that less fluid has to be injected (in the case of hydrodynamically driven experiments) results in the ability to test these products at a higher frequency.

Localized unilateral periorbital edema induced by aspirin.

BACKGROUND: Aspirin intolerance manifested as bronchospasm or urticaria/angioedema has been observed since the beginning of this century. OBJECTIVE: To report a novel case of intolerance to aspirin ingestion. METHODS: Case report; routine skin testing; pulmonary function testing; aspirin challenge. RESULTS: A 30-year-old man with a history of left ocular trauma at the age of 10 noted a 3-year history of left periorbital angioedema after aspirin but not other nonsteroidal anti-inflammatory drugs. Incremental oral aspirin challenge resulted in this unilateral symptomatology at a dose of 673 mg. CONCLUSION: To the best of our knowledge, this is the first reported case of unilateral periorbital edema following aspirin ingestion.

Progressive accumulation of bacterial lipopolysaccharide in vivo during murine acute graft-versus-host disease.

In a previous report the authors demonstrated that acute graft-versus-host disease (GVHD) was associated with pathologic amounts of tumour necrosis factor alpha (TNF-alpha) and the appearance of lipopolysaccharide (LPS) in the blood of GVH reactive mice just prior to death. In this study the authors have investigated the kinetics of LPS accumulation in different organs during the course of acute GVHD using a murine model. Unirradiated C57BL/6 x AF1 (B6AF(1)) mice were transplanted with C57BL/6 (B6) lymphoid cells and killed at predetermined times after transplantation for LPS analysis. Control animals were injected with either 60 x 10(6) B6AF1 lymphoid cells (syngeneic) or 60 x 10(6) irradiated (2000 rad) CBA lymphoid cells (allogeneic). Lipopolysaccharide began to appear in the liver and the spleen of GVH reactive mice from day 2 post-transplant and by day 10 all GVH reactive mice tested positive for hepatic and splenic LPS. Low levels of LPS were detected in some control mice from days 2 to 10 post-transplant but LPS was never detected after day 10 in control groups. Total hepatic and splenic LPS in acute GVH reactive mice peaked at a time coincident with the appearance of LPS in the serum and with the onset of mortality. These results demonstrate that tissue levels of LPS increase throughout the course of acute GVHD and are sufficient to trigger the release of pathologic amounts of TNF-alpha from primed macrophages resulting in the cachexia and mortality associated with acute GVHD in this model.

Macrophage priming and lipopolysaccharide-triggered release of tumor necrosis factor alpha during graft-versus-host disease.

In this report we have investigated macrophage (M phi) activity and tumor necrosis factor alpha (TNF-alpha) production during graft-vs.-host disease (GVHD). TNF-alpha production by M phi requires two signals: priming of M phi by interferon followed by triggering of TNF-alpha production and release by lipopolysaccharide (LPS). The state of M phi activation was examined in nonirradiated B6AF1 recipient mice injected with either 60 x 10(6) (acute GVHD) or 30 x 10(6) (nonlethal GVHD) parental B6 lymphoid cells. During the early phase of acute GVHD, administration of normally sublethal amounts of LPS-triggered release of significant amounts of TNF-alpha into the serum resulting in death of the animals within 36 h. Normal animals treated with the same dose of LPS neither died nor produced detectable amounts of serum TNF-alpha. In vitro studies demonstrated that M phi were primed during GVHD. The level of M phi priming was greater during acute GVHD than nonlethal GVHD since 100-fold less LPS was required to trigger killing of a TNF-alpha-sensitive cell line by M phi from acute GVHD animals. The amount of TNF-alpha released into the serum after LPS injection increased during the course of the GVHD and was significantly greater in acute GVH-reactive mice. Endogenous LPS was detected in the serum of acute GVH-reactive animals coincident with the onset of mortality. The data provide evidence that during GVHD M phi are primed as a result of the allogeneic reaction and that endogenous LPS therefore triggers M phi production of TNF-alpha resulting in the symptoms characteristic of acute GVHD.

Considerations for selecting nutrient-calculation software: evaluation of the nutrient database.

With the growing number of nutrient-calculation software packages on the market, potential users are faced with the increasingly difficult task of determining which system best meets their needs. Most published reviews of nutrient-calculation software focus on program features rather than on the quality of the nutrient database on which all calculations are based. This is unfortunate because program features are of little consequence if the nutrients calculated are not of acceptable quality. The purpose of this paper is to focus on the evaluation of the nutrient database as the foremost consideration in selecting nutrient-calculation software. Six questions that may be used as a guide for evaluating a nutrient database are presented and discussed.

Busulfan-induced suppression of natural killer cell activity.

The effect of repeated injections of busulfan, an alkylating agent, on immune response of CAF1 mice was studied. A single injection of busulfan or acetone (vehicle to solubilize busulfan) acutely suppressed mitogenic and allogenic responses that normalized at two weeks. Repeated injections of busulfan (four injections), on the other hand, showed a transient suppression of the mitogenic responses. Natural killer (NK) activity during the first ten days after busulfan or acetone injections remained normal. NK activity diminished significantly after two injections of busulfan, remained low after four injections, and did not recover within four months of rest. Prolonged suppression of NK activity may be implicated as playing a role in the emergence of T-cell lymphomas in mice injected with busulfan.

Norepinephrine in chronic paranoid schizophrenia: above-normal levels in limbic forebrain.

In postmortem examination of brains of four patients with chronic paranoid schizophrenia, above-normal norepinephrine levels were measured in the ventral septum, the bed nucleus of the stria terminalis, the nucleus accumbens, and the mammillary bodies. No changes were detected in other limbic forebrain regions, including the hypothalamus and the medial olfactory (preoptic) area. The results point to the possibility of a malfunction of limbic noradrenergic mechanisms in schizophrenia, especially the paranoid variety.

Dopamine in thelimbic regions of the human brain: normal and abnormal.

1. In the human brain, DA was found in appreciable amounts in most of the examined basal telencephalic limbic regions, with the nucleus accumbens having the highest mean level (3.38 microgram/g). In the cortical areas of the limbic lobe of Broca, DA could be measured with certainty only in the parolfactory gyrus (0.35 microgram/g). 2. In patients with Parkinson's disease, the DA concentration in the parolfactory gyrus and nucleur accumbens was markedly reduced, whereas little change was seen in the olfactory areas. Quantitatively, the DA decrease in the nucleus accumbens was of the same magnitude as in the caudate nucleus, being, in both regions, distinctly less severe than in the putamen. 3. In three cases of paranoid schizophrenia, there were no statistically significant changes of the mean levels of DA or HVA in the nucleus accumbens. However, the DA/HVA ratio was shifted noticeably in favor of HVA, possibly indicating an increase in DA turnover. This change was less pronounced in the putamen of these cases and was absent in the caudate nucleus. 4. The possibility of the substantia nigra contributing to the dopaminergic innervation of the human nucleus accumbens, as well as the significance of the observations on DA metabolism in the schizophrenic cases, is discussed.

Spinal reflexes and the concentrations of 5-HIAA, MHPG, and HVA in lumbar cereborspinal fluid after spinal lesions in man.

Descending bulbospinal pathways that employ specific neurotransmitter substances are known to be capable of modulating segmental reflex activity in the experimental animal. To determine whether this might also occur in man correlations have been sought between the activity in spinal reflex pathways and the lumbar cerebrospinal fluid (CSF) concentrations of 5-hydroxyindolacetic acid (5-HIAA), 3 methoxy-4-hydroxyphenylglycol (MHPG), and homovanillic acid (HVA) in 12 patients with complete or virtually complete spinal lesions. The concentrations of 5-HIAA and MHPG in lumbar CSF ARE REDUCED AFTER COMPLETE OR VIRTUALLY COMPLETE SPINAL LESIONS IN MAN. This may occur within 18 days of the lesion. MHPG concentrations appear to be inversely related to the level of the lesion. The HVA concentration in lumbar CSF is reduced when there is obstruction of the CSF pathways. No relationship could be demonstrated between the concentrations of 5-HIAA or MHPG in lumbar CSF and the activity in the spinal monosynaptic pathway (estimated from the proportion of the motoneurone pool activated by the Achilles tendon reflex or H reflex) or the activity of a spinal inhibitory mechanism (estimated by the degree of vibratory inhibition of the monosynaptic reflex). Patients with a tonic vibration reflex (TVR) tended to have higher MHPG levels. There appeared to be an association between low CSF HVA and enhanced vibratory inhibition of the monosynaptic reflex in the nine patients whose spinal lesions were complete.

The mechanism of adenosine diphosphate induced platelet aggregation: binding to platelet receptors and inhibition of binding and aggregation by prostaglandin E 1 .

1. Normal human blood platelets in stirred plasma were incubated with [(14)C]ADP for 10-360 sec and the aggregation responses were correlated with platelet bound radioactivity, the platelets being separated from the plasma within 25 sec of the end of the experiment.2. The platelet aggregation response, measured as a change in light transmittance through platelet-rich plasma, was related to the plasma [(14)C]ADP concentration and linearly related to the log platelet bound [(14)C]ADP 60-120 sec after addition of nucleotide to plasma.3. Thin layer chromatography of the platelet bound radioactivity showed that 78-90% was unmetabolized ADP, the remainder being AMP. Plasma radioactivity consisted of ADP, AMP and adenosine. There was no detectable radioactive cyclic AMP in either platelets or plasma.4. Further accumulation of radioactivity occurred after 180 sec but was not related to the aggregation response.5. Prostaglandin E(1) inhibited aggregation and platelet [(14)C]ADP accumulation when added to platelet-rich plasma 60 sec before [(14)C]ADP. There was a significant correlation between inhibition of aggregation and inhibition of [(14)C]ADP accumulation.6. Prostaglandin E(1) also reversed ADP aggregation when added to platelet-rich plasma after the nucleotide, with an accompanying decrease in platelet bound [(14)C]ADP.7. It is concluded that ADP induces platelet aggregation by binding to specific receptors probably located on the plasma membrane, and that prostaglandin E(1) inhibits this effect by interfering with the ADP binding.