Increase In Optical Density Research Articles

Enzyme-mediated precipitation of parent drugs from their phosphate prodrugs

Many oral phosphate prodrugs have failed to improve the rate or extent of absorption compared to their insoluble parent drugs. Rapid parent drug generation via intestinal alkaline phosphatase can result in supersaturated solutions, leading to parent drug precipitation. The purpose was to (1) investigate whether parent drugs can precipitate from prodrug solutions in presence of alkaline phosphatase; (2) determine whether induction times are influenced by (a) dephosphorylation rate, (b) parent drug supersaturation level, and (c) parent drug solubility. Induction times were determined from increases in optical densities after enzyme addition to prodrug solutions of TAT-59, fosphenytoin and estramustine phosphate. Apparent supersaturation ratios ( σ) were calculated from parent drug solubility at intestinal pH. Precipitation could be generated for all three prodrugs. Induction times decreased with increased enzyme activity and supersaturation level and were within gastrointestinal residence times for TAT-59 concentration≥21 μM ( σ≥210). Induction times for fosphenytoin were less than the GI residence time (199 min) for concentrations of approximately 352 μM ( σ=4.0). At approximately 475 μM ( σ=5.3) the induction times were less than 90 min. For estramustine-phosphate, no precipitation was observed within GI residence times. Enzyme-mediated precipitation will depend on apparent supersaturation ratios, parent drug dose, solubility and solubilization by the prodrug.

Evaluation of the post-antifungal effect (PAFE) of amphotericin B and nystatin against 30 zygomycetes using two different media.

The post-antifungal effect (PAFE) of amphotericin B and nystatin against 30 clinical zygomycetes was evaluated using two different media. PAFE is a suppression of fungal growth after limited drug exposure. The MICs of both drugs were determined using NCCLS M38-P guidelines. A spectrophotometric method was used to determine PAFE in vitro. Spores were exposed to amphotericin B and nystatin in RPMI-1640 or AM3 at concentrations of 4 x and 1 x MIC for 4 h for Absidia sp. and at 1 x and 0.5 x MIC for 1 h for the other strains. Drugs were eliminated by washing. Exposed and control spores were cultured in microtitre wells and incubated for 48 h. PAFE was calculated as T - C (Delta t) between the control and the exposure fungi. The first increase in optical density (OD0) was used to calculate PAFE and was considered significant when the value of the lower 95%CI of the exposed strain was greater than the upper 95%CI of the control. MIC ranges in RPMI-1640 were: 0.06-4 mg/L for amphotericin B and 0.5-8 mg/L for nystatin; MIC ranges in AM3 were: 0.06-2 mg/L for amphotericin B and 0.5-4 mg/L for nystatin. Killing was not observed at the concentration and exposure time used. In RPMI-1640, for amphotericin B the rank order for PAFE was Absidia corymbifera (5.6 h) > Rhizopus oryzae (5.2 h) > Mucor spp. (3.5 h) > Rhizopus microsporus (3 h), and for nystatin the rank order was Mucor spp. (5.8 h) > R. oryzae (3.3 h) > A. corymbifera (2.9 h) > R. microsporus (1.7 h). PAFE was not induced in Rhizomucor spp. PAFE was dependent on drug concentration.

Upregulation of calretinin immunostaining in the ferret inferior colliculus after cochlear ablation.

In many systems, including ascending auditory pathways, calcium-binding proteins are markers of specific neuronal circuits. Previous studies suggest that calretinin immunostaining may be a specific marker for circuits in the inferior colliculus (IC) that code timing information. We undertook experiments to determine the changes in calretinin immunostaining in the IC that take place in response to cochlear ablation. Cochlear ablation was performed unilaterally in ferrets just after hearing onset. Animals survived for 2-3 months after ablation and brains were then processed for calretinin immunocytochemistry. The mean optical density and stained area of the calretinin immunopositive plexus in the IC were determined for five coronal sections through the right and left IC. In controls (n = 3), measurements of these parameters in the central nucleus of the IC showed symmetry between the two sides. In experimental animals (n = 8) the calretinin immunopositive plexus contralateral to the cochlear ablation was denser and larger than that in either the ipsilateral IC or in the IC of control animals. The calretinin plexus in the ipsilateral IC was slightly less dense and smaller than in controls but the differences did not reach statistical significance. IC volume measurements and synaptophysin immunostaining analysis in the central nucleus of the IC revealed no statistical differences between ablated and control animals or between the two sides in ablated animals. The significant increase in both mean optical density and immunostained area of the calretinin plexus in the IC contralateral to the cochlear ablation may reflect an upregulation in calretinin expression in the nuclei that contribute to this plexus.

A Search for Intraday Variability in the Blazar PKS 2005-489

Rapid, multicolor optical monitoring carried out for a multiwavelength campaign during 2000 August 22–27 is presented for the bright and variable BL Lac object PKS 2005-489. Previous multiwavelength monitoring campaigns of PKS 2005-489 have found complex variability behavior both in flux density and in broadband spectrum, with different modes and timescales from days to hours. During this campaign PKS 2005-489 was observed to be in an unusual state, bright in the optical but faint in the X-ray, just prior to an X-ray flare that began on 2000 September 2. PKS 2005-489 was also observed to have a flatter optical spectrum than in prior epochs. A linear increase in optical flux density was observed during the first 5.2 days of the campaign. However, intraday and color variability were not detected. The large discrepancy between the ratio of X-ray to optical flux density observed during this campaign and that observed in prior epochs indicates a lack of long-term correlation between the two wave bands, and it illustrates that simple particle injection events in the jet are insufficient to explain the long-term variability behavior of this object. Twenty-three in-field standard stars are identified for future optical monitoring programs.

Grain growth of zircon pigment in tile glaze

Glazes for ceramic materials are often opacified by a zircon pigment. The increase in optical density is related to the number and size of pigment particles, which are well dispersed in the glass. Mechanical dispersion by grinding of a fine zircon powder in a raw glaze mixture results in an unoptimised pigment dispersion in the melted glassy phase at high temperature. A significant reduction in the number of particles and a simultaneous large increase in their size is observed. In this case the optical glaze density does not attain the expected value and a very large quantity of zircon must be added. In the present work it is shown that a large part of the zircon reacts with the glass phase during firing. Simultaneously, the remaining zircon grains undergo a large increase in grain size by Ostwald ripening through the liquid phase. This process is characterised by a low activation energy (79 ± 1 kJ mol-1) and a short diffusion path for Zr through the liquid phase between neighbouring grains. The path length is shorter than the size of the larger grains. In the usual firing range, both populations of smaller and larger grains vary in size, the smaller grains favouring growth of the larger grains.

Use of an ELISA for detection of antibody responses in Argentine boa constrictors (Boa constrictor occidentalis)

To develop mouse monoclonal and rabbit polyclonal antibodies against immunoglobulin of Argentine boa constrictors and to demonstrate the ability of these reagents to detect antibody responses in boa constrictors by use of an ELISA and western blot analysis. Two 3-year-old Argentine boa constrictors. Procedure-Boa constrictors were immunized with 2,4-dinitrophenylated bovine serum albumin (DNP-BSA). Each snake received biweekly inoculations of 250 microg of DNP-BSA (half SC, half IP) for a total of 6 inoculations followed by monthly inoculations for 3 months. Preimmune blood samples were collected. Subsequently, blood was collected immediately prior to each booster inoculation. Anti-DNP antibodies were isolated from immune plasma samples by affinity chromatography. Affinity-purified boa anti-DNP immunoglobulin was used for production of polyclonal and monoclonal antibodies. An ELISA and western blot analysis were used to monitor immune responses, for purification of boa anti-DNP immunoglobulin, and for assessment of polyclonal and monoclonal antibody specificity. A 6-fold increase in optical density (OD405) of immune boa plasma, compared with preimmune plasma, was detected by the polyclonal antibody, and a 12- and 15-fold increase was detected by monoclonal antibodies HL1787 and HL1785, respectively, between weeks 4 and 8. Results of western blot analysis confirmed anti-DNP antibody activity in immunized boa plasma and in affinity column eluates. Polyclonal and monoclonal antibodies detected specific anti-DNP antibody responses in immunized boas. Polyclonal and monoclonal antibodies recognized boa constrictor immunoglobulin. These antibodies may be useful in serologic tests to determine exposure of snakes to pathogens.

Lutein and Zeaxanthin Dietary Supplements Raise Macular Pigment Density and Serum Concentrations of these Carotenoids in Humans

Age-related macular degeneration (AMD) is thought to be the result of a lifetime of oxidative insult that results in photoreceptor death within the macula. Increased risk of AMD may result from low levels of lutein and zeaxanthin (macular pigment) in the diet, serum or retina, and excessive exposure to blue light. Through its light-screening capacity and antioxidant activity, macular pigment may reduce photooxidation in the central retina. Lutein supplements, at 30 mg/d, were shown previously to increase serum lutein and macular pigment density in two subjects. In this study, we compared the effects of a range of lutein doses (2.4- 30 mg/d), as well as a high zeaxanthin dose (30 mg/d), on the serum and macular pigment in a series of experiments. Serum carotenoids were quantified by HPLC. Macular pigment densities were determined psychophysically. Serum lutein concentrations in each subject reached a plateau that was correlated with the dose (r = 0.82, P < 0.001). Plateau concentrations ranged from 2.8 x 10(-7) to 2.7 x 10(-6) mol/L. Zeaxanthin was less well absorbed than an equal lutein dose, resulting in plateaus of approximately 5 x 10(-7) mol/L. The rate of increase in macular pigment optical density was correlated with the plateau concentration of carotenoids in the serum (r = 0.58, P < 0.001), but not with the presupplementation optical density (r = 0.13, P = 0.21). The mean rate of increase was (3.42 +/- 0.80) x 10(5) mAU/d per unit concentration (mol/L) of carotenoids in the serum. It remains to be demonstrated whether lutein or zeaxanthin dietary supplements reduce the incidence of AMD.

Non-hydroscopic vanilla doped dichromated gelatin holographic material

Abstract Dichromate gelatins are well-known holographic materials. By doping this material with synthetic vanilla a change in the spectral response from regular dichromate gelatin is observed as an increase in optical density. This mixture presents an unusual high humidity resistance. It was possible to record holographic diffraction gratings using an argon ion laser ( λ =488 nm). These gratings exhibit good diffraction efficiency in transmission, on the order of 60% at Bragg angle, with more than 1700 lines/mm spatial resolution. The material development process consists simply of dipping it into using a solution of water and isopropyl alcohol. A hypothesis on the hydroscopic response of this new photosensitive material is also presented.

Prenatal elevation of endocannabinois corrects the unbalance between dopamine systems and reduces activity in the Naples High Excitability rats

Several evidences suggest that endocannabinoids exert a neurotrophic effect on developing mesencephalic dopamine neurons. Since an altered mesocorticolimbic system seems to underlie hyperactivity and attention deficit in clinical and animal studies of attention deficit hyperactivity disorder (ADHD), prenatal elevation of anandamide has been induced in Naples high excitability (NHE) rats by inhibition of its reuptake. To this aim, pregnant NHE and random-bred females received a subcutaneous injection of AM-404 (1 mg/kg) or vehicle daily from E11 until E20. Young adult male offsprings were exposed to a spatial novelty (Làt-maze) for 30 min and the behavior was videotaped and analysed for indices of activity (travelled distance, rearing frequency) and attention (rearing duration). Moreover, morphological analysis of the brains was carried out that pertained to cytochrome oxydase as marker of metabolic activity and thyrosine hydroxylase as marker of the dopamine systems. The results indicate that prenatal AM-404 treatment significantly reduces activity by about 20% during the entire testing period and modifies the distribution of scanning times towards short duration episodes in the first part of the test only in NHE-treated rats. In addition, image analysis revealed a significant increase in relative optical density of TH+terminals in the dorsal striatum and substantia nigra of AM-404 treated NHE rats and minor changes in the dorsal cortex of AM-404 treated NRB rats. The data suggest a corrected unbalance between the two dopamine systems that apparently leads to reduced hyperactivity and modified scanning times in this animal model of ADHD. This, in turn, might open new strategies in the treatment of a subset of ADHD cases.

Manifestation of behavioural and physiological functions of Synechococcus sp. Miami BG 043511 in a photobioreactor

Synechococcus sp. Miami BG 043511, a unicellular marine cyanobacterium, offers possibilities for biotechnological purposes. It was tested for the first time in the present work as a component of specially designed biosolar system. The testing was carried out using a 4.35-l helical tubular photobioreactor. The cell culture of this cyanobacterium was found to exhibit persistent cyclic oscillations in O2 evolution and CO2 consumption during the growth in the photobioreactor under N2-fixing autotrophic conditions and continuous illumination. The cycles of these two activities during bubbling of the culture with air + 2% CO2 lasted for 23.5 h and were of the same pattern and phase. The cycles consisted of two phases: a short (8.3 h) and a long (15.2 h) phase, with a minor and a major peak of gas exchange, respectively. Additionally, the culture exhibited transient increase in optical density at each major peak of O2 evolution. The growth rate of the continuous culture (4 µg chl a ml–1) of the cyanobacterium, sparged with CO2-enriched air under light of 150 µE m–2 s–1, was 0.024 h–1. The culture in the photobioreactor produced an appreciable amount of H2 under argon + 2% CO2. However, it produced no H2 under air + 2% CO2. The activation of H2 production in the cyanobacterium by CO2-enriched argon was accompanied by frequent oscillations in the optical density, essential elongation of the cycle of O2 evolution and inhibition of the growth rate of the culture. H2 and O2 evolution changed with time in very similar oscillatory patterns, but inversely to each other. The results showed that Synechococcus sp. Miami BG 043511 could be successfully cultivated in the helical tubular type of biosolar system. It is also clear that further efforts should be made to extend our knowledge of this cyanobacterium.

SPONTANEOUSLY BEATING NEONATAL RAT HEART MYOCYTE CULTURE—A MODEL TO CHARACTERIZE ANGIOTENSIN II AT1 RECEPTOR AUTOANTIBODIES IN PATIENTS WITH PREECLAMPSIA

This report focuses on angiotensin II AT(1) receptor autoantibodies (anti-AT(1)-AABs) in preeclamptic women. An enzyme-linked immunosorbent assay was described. Biotinylated peptide was incubated with anti-AT(1)-AABs. Streptavidin-coated magnetic particles bind the protein-autoantibody complex. Detection of anti-AT(1)-AABs was performed using anti-human IgG3 peroxidase-coupled antibody. The color reaction of tetramethylbenzidine solution was stopped by adding 0.5 M H(2)SO(4). Optical density was measured at 450 nm (620 nm reference filter). Seventy-nine percent of anti-AT(1)-AAB-positive patients (measured by bioassay) showed an increase in optical density (>145%). The same biotinylated peptide was successfully used for purification of 6/6 anti-AT(1)-AABs. Chronotropic effects of purified antibodies were registered on primary cultured neonatal rat cardiomyocytes with the computer imaging system IMAGOQUANT. Western blot of coimmunoprecipitation of angiotensin II AT(1) receptor shows one band (molecular weight >40.0 kDa) in potassium thiocyanate eluate.

Spectral luminous efficiency as a function of age.

Spectral luminous efficiency function for a 2-deg field at a photopic level (100 Td) was measured for 91 observers by flicker photometry (FP) and for 97 observers by direct brightness matching (DBM), to find age-related change in the efficiency function as well as to obtain a reliable data set to be used in photometry. Observers ranged in age from 11 to 78 years. A gradual reduction of luminous efficiency with age was observed for both functions by FP and by DBM in the short-wave region, which was expected because of the age-related increase of optical density of eye lens. A similar age-related reduction of efficiency was observed in the long-wave region for the function obtained by DBM; this reduction was regarded as being due to reduced chromatic contribution to brightness with age. Principal components analysis on the spectral efficiency data and an analysis of the efficiency difference between the data obtained by DBM and FP confirmed this conclusion. Assuming a log-linear change in efficiency with age for any wavelength throughout the life span, spectral luminous efficiency function at any age was derived for photometric use.

Femtosecond UV Pump/Near-IR Probe Studies of the Solvent-Dependent Excited-State Decay Dynamics of Chlorine Dioxide

The excited-state decay and geminate-recombination dynamics of chlorine dioxide (OClO) are investigated using UV pump/near-IR probe spectroscopy. Experiments are performed with 200-fs time resolution on OClO dissolved in water, cyclohexane, acetonitrile, and chloroform. In all solvents, a reduction in optical density is observed at early times and is attributed to stimulated emission from the optically prepared 2A2 surface. The emission decays on the subpicosecond time scale to reveal an increase in optical density corresponding to the production of vibrationally hot ground-state OClO formed by geminate recombination of the primary photoproducts. Kinetic analysis of these data reveals that the excited-state decay time constant increases from ∼200 fs in water and cyclohexane to ∼400 fs in acetonitrile and chloroform. The vibrational-relaxation dynamics of OClO are also found to be solvent dependent in agreement with earlier work. Pump−probe anisotropy experiments on aqueous OClO are presented. In these stu...

Increased acid-sensing ion channel ASIC-3 in inflamed human intestine.

Acid-sensing ion channels (ASICs) are expressed by rat sensory neurons and may mediate pain associated with tissue acidosis after inflammation or injury. Our aim was to examine the molecular forms and localization of ASICs in human intestine and dorsal root ganglia using immunochemical techniques, and to measure the effects of inflammation and injury. Inflamed Crohn's disease intestine and injured human dorsal root ganglia, with appropriate controls, were studied by Western blotting and immunohistochemistry, using specific affinity-purified ASIC antibodies. In the Western blot, there was a significant three-fold increase in the mean relative optical density of the ASIC-3 55-kDa band (but not ASIC-1 or ASIC-2) in full-thickness inflamed intestine, as well as in separated muscle and mucosal layers. There was a corresponding trend for an increased immunoreactive density and increased number of ASIC-3-positive neurons in the myenteric and sub-mucous plexus of inflamed intestine. In dorsal root ganglia, immunoreactivity for all ASICs was restricted to a sub-population (about 50%) of small-diameter (nociceptor) sensory neurons, and was generally less intense after injury. Increased ASIC-3 in inflamed intestine suggests a role in pain or dysmotility, for which ASICs represent new therapeutic targets.

Induction of a lag phase by chiller temperatures in Escherichia coli growing in broth or on pork

When log phase cultures of Escherichia coli in brain–heart infusion (BHI) were cooled from 12°C to temperatures below 7°C (the minimum required for growth), the optical densities of cultures increased at declining rates for up to 6 days during incubation at temperatures between 6 and 3°C inclusive, but did not increase at temperatures ≤2°C. However, the numbers of E. coli recovered from cultures on selective or non-selective agars were similar at all times of incubation up to 8 days at temperatures below the minimum for growth. From optical density measurements it appeared that when log phase cultures were cooled to 2°C, then returned to 15°C, a lag developed with time at 2°C to reach a maximum of about 1 h after about 4 h. When cultures were returned to 12°C after times at 2°C between 0·5 and 8 days, the time during which optical densities did not increase was constant at about 2 h, but the initial rate of optical density increase declined with time at 2°C. On pork fat tissue the lag time, determined by increases in the numbers of E. coli cfu on tissues inoculated with cells returned from incubation at 2°C for 16 h to a growth permitting temperature between 7 and 30°C, was longer than the lag time determined from optical density measurements of broth cultures subjected to the same temperature regime. Lag times for E. coli adapted to and growing on normal pH pork lean tissue were longer than for E. coli on fat tissue, while unadapted E. coli did not initiate growth on lean tissue, after incubation at 2°C, at 12°C or lower temperatures. The observations indicate that lag phase development in log phase E. coli subjected to chiller temperatures is complex, and that prediction of lag resolution in log phase cells exposed to temperatures that fluctuate around the minimum for growth will require modeling of lag induction as well as lag resolution.

Cryptogenic epilepsy: an infectious etiology?

Cryptogenic epilepsy, the group of epilepsy syndromes for which an etiology is unknown, comprises approximately 20% of all epilepsy syndromes. We selected patients in this subgroup of epilepsy and tested them for evidence of Toxoplasma gondii IgG antibodies by the enzyme-linked immunosorbent assay. T. gondii is found in up to 20% of the U.S. population forming dormant brain cysts in the latent bradyzoite form. We investigated the hypothesis that dormant T. gondii infection might be associated with cryptogenic epilepsy. We selected patients with cryptogenic epilepsies and tested them for evidence of T. gondii IgG antibodies by the enzyme-linked immunosorbent assay. A control group was also tested for comparison. We have found a statistically-significant elevation of T. gondii antibodies among cryptogenic epilepsy patients as compared to controls [59% increase in optical density (OD), p = 0.013]. This association persisted after adjustment for subjects' gender and age in a multiple logistic regression model; however, it was no longer as statistically significant. Our results suggest that chronic T. gondii infection with brain cysts may be a cause of cryptogenic epilepsy.

Study of mandibular fracture repair using quantitative radiodensitometry: A comparison between maxillomandibular and rigid internal fixation

Purpose: This prospective study evaluated mandibular fracture repair after either maxillomandibular fixation (MMF) or rigid internal fixation (RIF) using the computer-assisted densitometric image analysis (CADIA) system. Patients and Methods: Fifty-two patients, 32 treated by MMF and 20 by RIF, were studied. Five postoperative panoramic radiographs were performed on each patient (immediately postoperatively and at 15, 30, 60, and 90 days) and the changes occurring in the optical density of the bone at and around the fracture line were analyzed. Results: An increase in optic density was observed in both groups at 15 days after treatment. At 30 days, a decrease in optical density was observed in both groups, being significantly greater in the MMF group. In the measurements performed at 60 days, an increased density was found in the RIF group, but the rate of optical density increase was more rapid in the MMF group. During the third month, the rates of optical density increase were similar in the 2 groups. Conclusions: The use of RIF results in more rapid bone mineralization than the use of MMF. © 2000 American Association of Oral and Maxillofacial Surgeons

Modification of Autolysis by Synthetic Peptides Derived from the Presumptive Binding Domain of Staphylococcus aureus Autolysin

The autolytic cell wall hydrolase of Staphylococcus aureus, Atl, contains three highly cationic repeats in the central region of the amino acid sequence, and the repeats are presumed to have the role of binding the enzyme to some components on the cell surface. To explain the possible function of the repeats, we synthesized a number of 10- to 30-mer oligopeptides based on the Atl amino acid sequence (Thr432-Lys610) containing repeat 1, and examined their effects on the autolysis of S. aureus cells. When the peptides were added to a cell suspension of S. aureus under low ionic strength conditions, five peptides, A10, A11, A14, A16 and B9, showed immediate increases in optical density (OD) of the cell suspension accompanied by decreases in viable cell counts. After the immediate increases, the ODs for A10 and A14 changed little in the first 2 hr. In contrast, the ODs for A11 and A16 decreased rapidly. When peptide A10 was added to suspensions of heat-killed whole cells, crude cell walls and a crude peptidoglycan preparation, their ODs were increased approximately 2-fold. In contrast, the OD was not increased when the peptide was added to a suspension of pure peptidoglycan from which anionic polymers had been removed. Light microscopic and transmission electron microscopic study showed that A10 and A14 inhibited autolysis and that A11 and A16 induced autolysis earlier than the control. These results suggest strongly that the peptides adsorb to and precipitate on the anionic cell surface polymers such as teichoic acid and lipoteichoic acid via ionic interaction. The effects of peptides on the autolysis may be the results of the modification of S. aureus autolysin activities. These peptides, especially the 10-mer peptide B9 (PGTKLYTVPW) that represents the C-terminal half of A10 and N-terminal half of A11, may be important segments for Atl to bind to the cell surface.

Glutamine synthetase in experimental meningitis: increased ratio of the subunits 3 and 2 may indicate enhanced activity

Glutamine synthetase (GS) activity is higher in the neocortex but not in the hippocampal formation of rabbit brain during Streptococcus pneumoniae meningitis compared to the respective brain region of uninfected control animals. One-dimensional polyacrylamide gel electrophoresis (1D-SDS-PAGE) revealed an apparent molecular mass ( M r) of 44 000 Dalton (Da) for GS from rabbit brain. After two-dimensional gel electrophoresis (2D-PAGE), followed by Coomassie-blue staining, GS separated into three distinct spots (S1, S2, S3). One additional spot (S4) occurred on the immunoblot. All four GS spots exhibited the same M r (44 000 Da), but differed in their isoelectric points. Densitometric evaluation of the two-dimensional maps revealed a strong increase of optical density (OD) of S3 in the frontal cortex of infected animals. The calculated OD ratio S3/S2 in the frontal cortex from rabbits with meningitis was 1.75±0.68 (mean±standard deviation). Compared to controls (0.85±0.39), this value was significantly increased ( p=0.0006). In the hippocampal formation, the ratio S3/S2 was nearly unchanged during meningitis. It is suggested that the ratio S3/S2 may indicate a neuroprotective feature of rabbit brain during meningitis since neuronal apoptosis occurs only in the dentate gyrus and not in the frontal cortex.

Effect of Cigarette Smoking on Oral Elastase Activity in Adult Periodontitis Patients

We have previously reported that elastase activity in oral fluids is significantly increased in most adult periodontitis patients. In some patients, however, elastase levels remain low despite the presence of deep periodontal pockets. In this study we explored whether or not smoking is related to the unexpected low elastase values in these patients. We determined what proportion of the periodontitis patients that showed low oral elastase values were smokers. Paraffin-stimulated saliva or oral rinse samples (3 ml of water, 30 second rinse) were assayed for elastase activity by incubating with 1 mM succinyl-alanyl-alanyl-valine-p-nitroanilide for 20 hours at 37 degrees C, and the color formation read with a spectrophotometer. Neutrophil numbers were analyzed by staining the cells in the oral rinse smear samples. In 2 patient groups, one in Helsinki, Finland (n = 46) and the other in Vancouver, British Columbia (n = 25), 63% and 83%, respectively, of the adult periodontitis patients who had one or more pockets > or =6 mm and had low oral elastase values (increase of optical density <0.5) were smokers. Non-smoking periodontitis patients had elevated neutrophil numbers compared to healthy subjects, while the smoking patients showed no significant change. Next we analyzed elastase levels in stimulated whole saliva in a group of smokers (n = 300) and those who had quit smoking (n = 102). Smokers had significantly lower oral elastase levels than former smokers in both advanced and moderate periodontitis groups. In this subject group, 56% of all smokers with periodontitis (at least one pocket > or =6 mm) had oral elastase values less than 0.5 U while only 31% of those patients who had quit smoking had low values. Cigarette smoking leads to lowered elastase and neutrophil levels in the oral cavity. The oral neutrophil elastase assay, therefore, cannot be used to measure the periodontal status of smokers.