Benzalkonium Chloride Treatment Research Articles

Effects of myenteric denervation on gastric epithelial cells and gastric emptying.

The influence of myenteric denervation on gastric emptying and epithelial cell population was studied by chemical lesion of myenteric neurons of rat stomach with benzalkonium chloride. Three groups were evaluated: denervated, denervated with pyloroplasty, and control. After three months, the animals were submitted to functional (gastric emptying of liquids) and morphological (neuronal counting; mucosal area, height, and volume; mucous, chief, and parietal cell population; parietal cell area; and gastrin-G and somatostatin-D cell population) studies. After benzalkonium chloride treatment, there was significant delay in gastric emptying of liquids and an increase in mucosal area of all gastric portions, in antral mucosal volume, in parietal cell area, and gastrin-G cell and somatostatin-D cell populations. These changes did not occur when denervation was combined with pyloroplasty, indicating that after denervation, gastric distension and stasis are the major stimuli for parietal cell hypertrophy and G and D cell hyperplasia

Effects of Selected Chemotherapeutants on Nitrification in Fluidized-Sand Bioftlters for Coldwater Fish Production

Four fish chemotherapeutants, formalin, benzalkonium chloride, chloramine-T, and hydrogen peroxide were evaluated for their effect on the nitrification efficiency of fluidized-sand biofilters. The chemotherapeutants were added at conventional concentrations to two small-scale (2,200 L) coldwater recirculating rainbow trout (Oncorhynchus mykiss) culture systems each containing six fluidized-sand biofilters operating in parallel. Nitrification efficiency of biofilters was calculated before and after chemotherapeutant treatments by determining ammonia removal efficiency at ambient conditions, and also when challenged with a sudden increase of ammonium chloride at a concentration four times that of the ambient total ammonia-nitrogen (TAN). Two formalin treatments in recycle bath mode at 167 and 300 ppm were conducted with only the 300 ppm treatment having a significant negative effect on biofilter nitrification efficiency. Four single benzalkonium chloride treatments of one and 2 ppm were conducted; two static bath treatments and two recycle bath treatments. Of these four tests, only the recycle bath treatments caused biofilter nitrification efficiency to be significantly impaired. Two multiple treatments with benzalkonium chloride were conducted: one static bath treatment and one recycle.bath treatment. These treatments caused ammonia removal efficiency to decrease by 18% in the static bath treatment and by 63% in the recycle bath treatment. Of these two tests, only the recycle bath treatment caused a significant impairment of nitrification. Single static bath and recycle bath treatments with 9 ppm of chloramine-T both resulted in significant impairment of nitrification, as did a 12 ppm multiple static bath treatment. A single static bath treatment with 100 ppm of hydrogen peroxide caused almost total failure of nitrification within 24 h of treatment but biofilters were able to remove 23% of TAN within 48 h of treatment.

Factors influencing a suspension test method for antimicrobial activity of disinfectants.

Factors influencing the numbers of Escherichia coli DSM 682 and Staphylococcus aureus ATCC 6538 surviving exposure to disinfectants were evaluated by factorial design. Aerobic conditions during pre-cultivation rendered E. coli more resistant to the lethal activity of benzalkonium chloride (BC) and a disinfectant containing grape fruit extract (GSE), whereas Staph. aureus became more sensitive. The degree of shaking and the pre-growth medium (tryptone soy broth or Mueller-Hinton broth) did not influence the result of the bactericidal test. The number of E. coli surviving BC treatment was significantly lower if the neutralizing broth contained thiosulphate, plate pouring was used instead of plate spreading, or the plates were incubated at 37 instead of 30 degrees C. The negative effect of plate pouring was also found with Staph. aureus. The use of filtration without prior neutralization of the disinfectant decreased the numbers of chlorine-treated, but not BC-treated, E. coli. The results showed that rigorous standardization is necessary to obtain good reproducibility of bactericidal suspension tests.

Morphological and functional changes after benzalkonium chloride treatment of the small intestinal thiry-vella loop in rats

The aim of this work was to study the effects of benzalkonium chloride (BAC) treatment on the small intestine and its functioning in rats surgically prepared with Thiry-Vella intestinal loop. The loops were treated with either BAC, which ablated much of the myenteric plexus and extrinsic innervation, or with physiological saline (SAL). In vivo drinking experiments were performed to examine the effect on fluid intake and behavioral indices of distending the loop with a balloon. Spontaneous motility and its changes induced by acetylcholine (ACh) and histamine (His) were studied on isolated stripes in vitro. Finally, samples from the loops were examined histologically. Though reduction of the cell number was less than expected and no differences of the thickness of the muscular layer between the two groups was observed, BAC treatment altered the pattern of spontaneous activity and also the sensitivity to ACh and His in isolated stripes. In vivo distension of the SAL-treated loops reduced fluid intake and produced signs of aversivity; these effects were absent in the BAC-treated group. Our results show that despite the differences in the degree of ablation from those obtained by others, BAC treatment can be used to study the mechanisms underlying the effects of the enteral stimuli on the behavior.

Effect of intracolonic benzalkonium chloride on trinitrobenzene sulphonic acid‐induced colitis in the rat

We investigated the effects of benzalkonium chloride (BAC) on trinitrobenzene sulphonic acid (TNBS)-induced colitis in rats. TNBS was administered intrarectally before and/or after BAC treatment. In the first study, the effects of treatment with BAC 6, 12 or 24 h after TNBS were examined. In the second study, animals were treated with BAC before, after or before and after TNBS, and were examined 7 days later. The severity of colitis was assessed by macroscopic and histological scoring of the colonic damage and by determination of colonic myeloperoxidase (MPO) activity. Macrophages and CD4+ and CD8+ T cells were examined by immunohistochemistry. When BAC was instilled into the colon 6, 12 or 24 h after TNBS, weight loss and macroscopic and histological features of the colon were similar to that of controls (TNBS alone). In contrast, MPO activity was significantly reduced in all three groups post-treated with BAC. In the groups examined 7 days after TNBS treatment, rats post-treated with BAC exhibited increased weight gain and significantly reduced macroscopic damage and MPO activity compared to the TNBS control group. Rats pre-treated with BAC exhibited less macroscopic damage of the colon than rats receiving only TNBS, but histological damage, MPO and weight gain were unchanged from TNBS controls. Immunohistochemistry revealed that BAC pre-treatment increased the numbers of macrophages and T cells in the colon. After TNBS treatment, macrophage accumulation was evident in the colon, but T cells were scarce. However, these cells were preserved or enhanced in the colonic mucosa in TNBS-treated rats that had been pre-treated with BAC. Treatment with BAC, particularly after induction of colitis, produces a significant reduction in the severity of tissue injury and inflammation through mechanisms that are not fully understood.

Multiple mechanisms contribute to myenteric plexus ablation induced by benzalkonium chloride in the guinea-pig ileum.

Ablation of rat myenteric plexus with benzalkonium chloride has provided a model of intestinal aganglionosis, but the degenerative responses are not well understood. We examined the effects of this detergent on neurons and glia, including expression of c-Myc, c-Jun, JunB, and c-Fos, and on immunocytes in the guinea-pig ileum. Benzalkonium chloride (0.1%) or saline was applied to the serosal surface of distal ileum. Tissues were analyzed 2, 3, or 7 days later and compared with cyclosporine-treated and untreated animals. More than 90% of myenteric neurons were destroyed in ileal segments 3-7 days after benzalkonium-chloride treatment. Glia withdrew processes from around neurons after 2 days and were mostly gone after 3 days. Neuronal c-Myc began to disappear while c-Fos, c-Jun, and JunB were evident in some neuronal nuclei after 2 or 3 days. After 3 days, widespread apoptosis was evident in the myenteric plexus. Populations of T cells, B cells, and macrophage-like cells in untreated and saline-treated myenteric plexuses were substantially increased 3 and 7 days after benzalkonium-chloride treatment. Cyclosporine delayed significant neuronal loss. We conclude that a variety of degenerative mechanisms may be active in this model, including an immune response which may actively contribute to tissue destruction.

Relation between cholecystokinin and antral innervation in the control of gastric emptying in the rat.

BACKGROUND: Antral motility and the hormone cholecystokinin (CCK) are major determinants of the rate of gastric emptying. The relation between CCK and antral neurons in regulating gastric emptying is uncertain....

The relationship between myenteric neuronal denervation, smooth muscle thickening and epithelial cell proliferation in the rat colon.

The effects of myenteric neuronal denervation on smooth muscle thickening and epithelial cell proliferation were studied in the descending colon of rats treated by serosal application of 2 mM benzalkonium chloride (BAC) for 30 min. Control animals were treated with saline (0.9% NaCl). The animals were divided into six groups of 13 animals each and killed 10, 45 and 120 days after BAC treatment. A significant reduction in neuron number was observed in the myenteric plexus of animals treated with BAC, as well as smooth muscle thickening and an increase in crypt cell population, crypt cell production per crypt and a decrease in cell cycle time. These findings permit us to conclude that a relationship may exist between the increase of epithelial cell proliferation, smooth muscle thickening and myenteric neuron denervation in the descending colon caused by BAC, the latter probably playing an important role in the integration of the other two.

Benzalkonium chloride treatment induces programmed cell death in myenteric neurons of the guinea pig ileum: [formula omitted], M.J.S. Miller∗, W. Ho and K.A. Sharkey. Depts. of Medical Physiology, The University of Calgary, Alberta, Canada and ∗Pediatrics, Louisiana State University Medical Center, New Orleans, LA, USA

Benzalkonium chloride treatment induces programmed cell death in myenteric neurons of the guinea pig ileum: [formula omitted], M.J.S. Miller∗, W. Ho and K.A. Sharkey. Depts. of Medical Physiology, The University of Calgary, Alberta, Canada and ∗Pediatrics, Louisiana State University Medical Center, New Orleans, LA, USA

Myenteric plexus destruction alters morphology of rat intestine

Background: It has been shown previously that myenteric plexus destruction by benzalkonium chloride (BAC) increased villus height, crypt depth, and muscle thickness, suggesting that these neurons influence intestinal morphology. A nonspecific trophic effect of BAC, intraluminal stasis, and inflammation resulting from the chemical treatment could also be causes for these changes. Our goals were to (1) show that the morphological sequelae of BAC treatment are caused by myenteric plexus removal and not the factors listed above, and (2) determine whether segmental myenteric plexus removal alters morphology elsewhere in the small intestine. Methods: Six groups of rats were studied: control, chemical denervation (3 mmol/L BAC), surgical denervation, intraluminal stasis produced by partial obstruction, chemical inflammation (5% acetic acid), and surgical inflammation (serosa removal only). Tissue for histological study was taken from the treated segment, 15–20 cm proximal to the treated segment, and 5–10 cm distal to the treated segment 28 days after treatment. Results: Chemical and surgical denervation reduced the number of myenteric neurons by 94% and 98%, respectively. Denervation had a direct effect on morphology; it increased villus height, crypt depth, and muscle thickness in the treated and proximal segments, but only muscle thickness was increased in the distal segment. The other treatments had minimal morphological sequelae. Conclusions: Segmental myenteric plexus removal alters the mucosa in the treated and proximal segments but influences muscle thickness throughout the intestine.

Changes in the structure and regeneration mode of the rat small intestinal mucosa following benzalkonium chloride treatment

Tritiated thymidine was administered IP to rats that had been exposed to benzalkonium chloride in the duodenum, jejunum, and ileum, resulting in neuronal ablation. Epithelial cell proliferation and migration were studied 21 and 7 days after treatment. Significant hyperplasia and hypertrophy of the villi and crypts was seen from day 7 on. This was half as pronounced as that of the muscle layer, whose maximal percent increase was not seen until day 21. In the crypt, the proliferation had increased significantly (65% 3H index corrected) and its zone had expanded proportionally to the total crypt depth. After an average of 36 hours in the ileum (48 hours in normal rats), labeled cells reached the tip of the lengthened villi, reflecting significantly accelerated migration. Concerning the distributional pattern of the labeled cells in the crypt, a nonsignificant shift to the lower two thirds of the crypt could be distinguished. From this the author concludes that treatment with benzalkonium chloride influences the proliferation and migration of the epithelial cells in the treated area. These alterations may result from loss of the myenteric plexus, but other factors cannot be excluded.

The chronological relationship between the thickening of smooth muscle, epithelial cell proliferation and myenteric neural denervation in the rat jejunum

The jejunum of rats was treated by serosal application of a 0.2% solution of benzalkonium chloride (BAC) for 30 min. Control animals were treated with saline (0.9% NaC1). The animals were allocated to eight groups of 10 rats each and sacrificed 15, 30, 45, 60 days after BAC treatment. Segments were removed from the jejunum for neuronal counting, measurement of the smooth muscle area and morphokinetic study of the epithelium. There was a significant reduction in neuron number in the myenteric plexus 30 days after BAC treatment, thickening of smooth muscle 15-60 days after BAC treatment, but no change in epithelial cell proliferation in the jejunum at either time.

Effect of chemical ablation of myenteric neurons on neurotransmitter levels in the rat jejunum

We have quantified neurotransmitter changes in the rat jejunum in which the myenteric neurons were ablated by serosal application of benzalkonium chloride. Within 2 days after benzalkonium chloride treatment, there was a 40% reduction in the activity of choline acetyltransferase, a specific marker for cholinergic neurons, and a 25% reduction in the amount of vasoactive intestinal peptide per centimeter length of jejunum. By 15 days, levels were comparable to those in control segments, and by 45 days after myenteric neuronal ablation, levels in treated tissues were twice those in controls. In contrast, we observed no reduction in the amount of leucine-enkephalin per centimeter length of jejunum at early times after benzalkonium chloride treatment, although by 45 days, levels of this neurotransmitter in treated segments of jejunum were more than twice those in controls. Significant increases in muscle thickness and tissue weight were also observed at 15, 30, and 45 days after myenteric neuronal ablation. Thus we have observed that in response to chemical ablation of myenteric neurons in the rat jejunum, there is a thickening of the smooth muscle layers and a compensatory increase in the production of certain neurotransmitters by the surviving neuronal elements in the gut.

Differentiation between myenteric plexus and longitudinal muscle of the rat jejunum as the site of action of putative enteric neurotransmitters

The contribution of the myenteric plexus in the mechanical responses of rat jejunal longitudinal muscle produced by several enteriic nerve substances was evaluated. The myenteric plexus of a segment of rat jejunum was destroyed by serosal application of benzalkonium chloride (BAC). Fifteen days after BAC treatment, both the BAC-treated and an orad control jejunal segment were removed and the mechanical responses of the longitudinal muscle producde by the following substances were examined: substance P, acetycholine (ACh), 5-hydroxytryptamine (5-HT), cholecystokinin octapeptide (CCK-8), norepinepgrine, vasoactive intestinal peptide (VIP), bombesin, [Leu 5]enkephalin and somatostatin. Our results indicate that: (1) substance P and norepinephrine produce their mechanical responses by acting predominatly on the longitudinal smooth muscle; (2) 5-HT, CCK-8, ATP, VIP and neurotensin act lpredominantly through the myenteric plexus; (3) ACh prossesses both direct annd indirect actions; and (4) because the responses to [Leu 2]enephalin, bombesin and somatostatin were equivocal, a conclusion as to their site of action could not be made with this preparation.

Selective myenteric neuronal denervation of the rat jejunum: Differential control of the propagation of migrating myoelectric complex and basic electric rhythm

Serosal application of benzalkonium chloride (BAC), a cationic surfactant, was used to selectively ablate the myenteric neurons of the rat jejunum. The myoelectric activity of the BAC-treated area and the areas both orad and caudad to it were assessed. In the jejunal segment devoid of myenteric neurons, the basic electric rhythm (BER) pattern was erratic and the amplitude of the BER was attenuated. The BER frequency of the jejunal area caudad to the BAC-treated area was 30.7 ± 0.73 cycles/min, which was significantly reduced from the normal BER frequency (37.7 ± 0.64 cycles/min). Spike activity was normal in areas both orad and caudad to the treated area, existing in regular cycling bursts (migrating myoelectric complex). Spiking in the treated area did not appear until ~13–17 days after BAC treatment. These spikes, though of greater duration and lower frequency than the adjacent areas, always appeared after an orad burst and were followed by a caudad burst. In addition, the following motility parameters of the regions orad and caudad to the treated area were not significantly different from control animals: burst duration, period, and burst propagation velocity. In conclusion, the present investigation has demonstrated that BAC-induced ablation of the myenteric neurons in the rat jejunum disrupts the BER but not the migrating myoelectric complex propagation. This suggests that the myenteric neurons play a modulatory role in the generation and propagation of the BER, whereas humoral factors or the submucosal neurons may be more important in the control of the migrating myoelectric complex.

Studies on a new proteolytic enzyme from Achromobacter lyticus M497-1 I. Purification and some enzymatic properties

Achromobacter lyticus M497-1 produces three kinds of alkaline proteases (protease I, II and III) in culture medium along with the bacteriolytic enzyme (Masaki, T., Nakamura, K., Isono, M. and Soejima, M. (1978) Agric. Biol. Chem. 42, 1443–1445). Among these three proteases, Achromobacter protease I (EC 3.4.21.-) shows strict splitting for lysine residues at the carboxyl side of the splitting point. This enzyme was purified through a sequence of benzalkonium chloride treatment, acetone fractionation, CM-cellulose and DEAE-cellulose treatment, chromatography on AH-Sepharose 4B and isoelectric focusing method. This form was shown to be homogeneous by polyacrylamide gel electrophoresis and ultracentrifugation analysis. The physicochemical properties of the enzyme were: M r 30 500; partial specific volume ( ν ), 0.717 ml/g; intrinsic viscosity (η), 0.0385 dl/g; isoelectric point (p I) 6.9; and E 1cm 1% at 280 nm, 18.77. The enzyme was composed of 294 residues of amino acid per molecule, with glycine as NH 2-terminal and lysine as COOH-terminal amino acids. The optimum pH values with casein, Bz-Lys-pNA and Tos-Lys-OMe were 8.5–10.7, 9.0–9.5 and 7.8–8.2, respectively. The enzyme was inhibited by iPr 2P-F, PhCH 2SO 2F and Tos-LysCH 2Cl but not by Tos-ArgCH 2Cl, EDTA, o-phenanthroline and PCMB.

Inactivation of Mycobacterium bovis in meat products.

The time-temperature combinations necessary to destroy Mycobacterium bovis in meat products were determined. In any given time, M. bovis was destroyed at temperatures 6 to 7 degrees C (ca. 12 degrees F) lower than those necessary for destruction of members of the Mycobacterium avium-Mycobacterium intracellulare complex. Hence, any processing heat adequate to kill M. avium-M. intracellulare-complex organisms will provide a very large safety factor with respect to M. bovis. Benzalkonium chloride treatment of wiener specimens for cultural examination effectively destroyed the normal flora of wiener emulsion without reducing the numbers of M. bovis. Treatment with a phenolic disinfectant followed by formaldehyde vapor was effective in disinfecting equipment contaminated with meat emulsion containing M. bovis.