Concentrations Of Formalin Research Articles

Identification of Oligella ureolytica from Formalin-Embalmed Cadavers

Formalin is a widely used fixative for embalming of cadavers with a well recognized antimicrobial activity. However, with improper preservation techniques some human pathogens such as Oligella ureolytica can overcome this feature of formalin. The current study was performed to detect this microorganism and consequently prevent its risks to medical students and embalmers. Swab and tissue samples were collected from lesions, intact area, and surrounding surfaces of three formalin embalmed cadavers from tutorial anatomy lab in the college of medicine - HMU. Samples were subsequently transferred to nutrient, MacConkey, and blood agar then, purified colonies were subjected to biochemical tests and microscopic observation. Accordingly, advanced automated instrument was applied to confirm identification. The isolated microorganism was then inoculated under increasing formalin concentrations. The genus Oligella ureolytica was identified which appeared as Gram negative, rod shape with singular arrangement under microscopic observation. The biochemical tests revealed positive for urease, oxidase, catalase, and motility with no evidence for hemolysis. The growth of Oligella ureolytica was significant at 1% and 2% and low at 5% and 10% formalin concentration but no growth at higher concentrations.There are many reasons to choose formalin as fixative for embalming. However; it is not totally able to protect cadavers from decomposition by microorganisms like Oligella ureolytica. Thus, possible risk of contamination for medical students and embalmers exists when a fixative of low concentration was used.

Eco-friendly method for the extraction of earthworms: Comparative account of formalin, AITC and Allium cepa as extractant

Earthworms play an important role in ecosystems and act as a soil engineers changing the physico-chemical properties of soil. Eco-friendly methods for the extraction of earthworms are needed to assess earthworm abundance, biomass and their diversity. In this study, a comparison was made to find out the most effective chemical expellants for the extraction of earthworms in different concentrations of Formalin, Allyl isothiocyanate (AITC) (0.25, 0.50, 0.75 and 1.0g/l), Allium cepa solution (50, 100, 150 and 200g/l) and distilled water as a control. Three species of earthworms from the family Megascolecidae have been extracted belonging to two ecological groups: the endogeic species Metaphire posthuma as well as the anecic species Lampito mauritti and Amynthas morissi. The number of extracted individuals across all species and age classes was significantly affected by the type of vermifuge. A. cepa solution was more efficient than Formalin and AITC for extraction of worms and it is also similarly efficient for extracting adult worms and juveniles. Only for the number of extracted juveniles and individuals of A. morissi the effects of formalin and AITC were not significantly different (p>0.05), in all other cases AITC was more efficient than formalin. It was found that A. cepa solution expelled 66.15% and 53.30% more numbers of earthworms than AITC and formalin respectively. We conclude that A. cepa extraction solution is a suitable and eco-friendly alternative to AITC and formalin for sampling of endogeic and anecic earthworms.

Antiparasitic efficacy and blood effects of formalin on Arapaima gigas (Pisces: Arapaimidae)

This study evaluated the in vitro and in vivo antiparasitic efficacy of formalin against Dawestrema cycloancistrium, the effects on the physiological response of Arapaima gigas and the residual action on fish muscle after 96h of exposure. As regards the in vitro assay, 0, 22, 44, 66, 88, 110, 330, 660 and 880 mg L−1 formalin were tested. After 1h of exposure to 660 and 880 mg L−1 formalin, there was a 100% mortality of D. cycloancistrium as well as after 2h of exposure at 330 and 110 mg L−1 and 3h of exposure at 44, 66 and 88 mg L−1. Concerning the in vivo test, when fish were exposed to formalin at 0, 220, 330, 440 and 550 mg L−1, there was 100% survival at all concentrations and exposure times evaluated. Baths of 1h with 440 and 550 mg L−1 formalin showed 93.3% and 99.3% efficacy respectively. However, the baths of 12h with 55 and 66 mg L−1 formalin had the efficacy of 44.5% and 55.5% respectively. In 1h baths with 220, 330, 440 and 550 mg L−1 formalin, hematocrit, hemoglobin, number of total erythrocytes, mean corpuscular volume, mean corpuscular hemoglobin concentration, mean corpuscular hemoglobin, plasma glucose levels, cortisol, total proteins, chloride, calcium, sodium, potassium and magnesium of the fish presented no differences in relation to the control values. However, in baths of 12h with 33, 44, 55 and 66 mg L−1 formalin, there was a decrease in hematocrit, plasma levels of calcium and chloride, and increased levels of glucose and cortisol, depending on the concentration of formalin used. In the fish muscle, the formalin residue decreased after 96h in all concentrations and periods evaluated, returning to values close to the control ones. The results indicate that formalin had its efficacy successfully proved in the treatment against D. cycloancistrium at higher concentrations such as 440 and 550 mg L−1 formalin and shorter exposure time (1h) without compromising fish homeostasis and consumer food safety. Statement of relevanceThe manuscript represents original research on use of formalin in vitro and in vivo for treating infection by monogenoidean Dawestrema cycloancistrium in Arapaima gigas, the giant fish from Amazon. In the fish, muscle the residue levels of formalin after exposure was also investigated. Formalin have efficacy in the treatment against D. cycloancistrium at higher concentrations (440 and 550 mg.L−1) of formalin and shorter exposure time (1h) and without compromising A. gigas homeostasis and consumer food safety.

Effects of concentration and vendor specific composition of formalin on postmortem MRI of the human brain.

Formalin fixation prevents tissue autolysis by crosslinking proteins and changes tissue microstructure and MRI signal characteristics. Previous studies showed high variations in MR relaxation time constants of formalin fixed brain tissue, which has been attributed to the use of different formalin concentrations. Our investigations confirmed the influence of formalin concentration on relaxation times and unexpectedly revealed an influence of vendor specific formalin composition, which has not been investigated so far. We systematically analyzed relaxation times of human brain tissue fixed with 4% and 10% formalin compared with unfixed condition at 3 Tesla MRI. Furthermore, we assessed relaxation times of nine formalin solutions from different vendors and performed comparisons of their magnetic susceptibility by SQUID (superconducting quantum interference device) magnetometry. Tissue relaxation times decreased approximately twice as fast using 10% than in 4% formalin fixation. The vendor specific composition of the formalin solutions and concentration dependent paramagnetic effects showed a substantial contribution to differences in relaxation times of formalin. Our study demonstrates that differences of the formalin composition have substantial effects on MRI signal characteristics after fixation, which can explain the divergence of reported relaxation times beyond the effect of differences in formalin concentration. Magn Reson Med 79:1111-1115, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Toxicity of Four Chemotherapeutic Agents to Rabbitfish Siganus rivulatus

AbstractAs aquaculture evolves from extensive pond culture to intensive tank and cage systems, chemical dips and baths are increasingly being used to treat a concomitant increase in ectoparasitic and bacterial infestations. Some of the main disease‐causing agents are ectoparasites on the skin and gills of fish. Consequently, application of chemotherapeutics is increasing in aquaculture industries in order to control outbreaks of parasitic infestations. However, the toxic effect of commonly used chemotherapeutic agents on specific aquacultured fish species is often unknown. The present work was performed to test the effect of four commonly used chemical treatments on rabbitfish, Siganus rivulatus. The lethal concentrations for 50% of population (LC50) of formalin, copper sulfate, potassium permanganate, and hydrogen peroxide for S. rivulatus juveniles treated for 1 h were assessed. Formalin and potassium permanganate tolerance values were determined by calculating 72‐h LC50 values through probit analysis. The 72‐h LC50 values for the formalin toxicity tests were 551.0 and 1.68 mg/L, respectively. LC50 of copper sulfate and hydrogen peroxide could not be determined from the concentrations tested but were found to be >3 and >700 mg/L, respectively. Accordingly, treatment concentrations of formalin and potassium permanganate used for other fish species could be lethal to S. rivulatus, but the species appears to be quite tolerant to copper sulfate and hydrogen peroxide.

Optimizing the process of inactivating influenza virus subtype H9N2 by formalin in the production of killed avian influenza vaccine

Avian influenza is one of the most important diseases in avian industry, which also threats human population. Thus, vaccination is necessary for controlling this viral disease. In this study, killed vaccine of avian influenza subtype H9N2 and formalin solution (for virus inactivation) were used. It is necessary to study the effect of different factors such as formalin concentration, as well as incubation temperature and duration on inactivation process. For this purpose, after preparation and measurement of antibody titers of vaccinal strains of avian influenza, 27 experimental samples of H9N2 avian influenza virus were prepared at different formalin concentrations (0.1%, 0.05%, and 0.025%), at different incubation temperatures (4 °C, 25 °C, and 37 °C), and in different incubation durations (12, 18, and 24 h). In addition, three control samples were prepared at three different test temperatures without adding formalin. All the samples were evaluated by inactivation test, hemagglutination assay, and measurement of free formaldehyde. All the experiments were repeated within three consecutive periods. Considering the findings and destructive effects of long incubation durations at 37°C on antigens, the temperature of 25 °C was more suitable. Furthermore, the free formaldehyde amounts at different concentrations at 25 °C were slightly different in comparison with 37 °C. Therefore, formalin concentration of 0.1% at 25 °C completely inactivated the virus within 24 h and was proposed as the optimal condition.

Investigations on the effect of formalin and iodophor on embryo and larvae development in pikeperch, Sander lucioperca

ABSTRACTAn experiment was conducted to evaluate the effects of incubating pikeperch, Sander lucioperca, eggs in formalin and iodophor solutions for 15 min on embryo survival, the hatching rate, as well as on the rate of misshaped larvae, in order to develop methods for egg surface disinfection. Embryos in the morula stage, in the epiboly stage, and at the beginning of heart beat and blood circulation tolerated formalin concentrations up to 1,500 ppm for 15 min. However, they were very susceptible to iodophor treatment, as >0.1% iodophor solution (=13 ppm active iodine) significantly decreased the percentage of ready-to-hatch embryos and the percentage of hatched larvae. These data of this study recommend the use of formalin at a concentration of up to 1,500 ppm to disinfect pikeperch eggs.

Two in vitro methods for screening potential parasiticides against Ichthyophthirius multifiliis using Tetrahymena thermophila.

Ichthyophthirius multifiliis (Ich) is a ciliate parasite that infects many species of freshwater fishes worldwide and causes heavy economic losses in aquaculture. Currently, parasiticides for controlling this parasite are limited, and few pond-practical chemical therapies exist. Hence, the search for new parasiticides is urgently needed. One challenge confronting the screening of potential parasiticides is the difficulty in raising enough parasite for efficacy testing as Ich is an obligate parasite. This study used species of Tetrahymena, Ich-related and cultivable ciliate protozoa, to evaluate two in vitro methods to test parasiticides. Plate counting and MTS assays (CellTiter 96® AQueous Non-Radioactive Cell Proliferation Assay) were used to compare lethal concentrations or median lethal concentrations (LC50) of copper sulphate, formalin and malachite green between T. thermophila and Ich theronts or between T. thermophila and Ich tomonts. The parasiticides that killed T. thermophila have been demonstrated to kill theronts or tomonts. These in vitro methods using T. thermophila can be used to screen novel parasiticides against Ich.

Assessment of Formaldehyde Levels in Local and Imported Fresh Fish in Ghana: A Case Study in the Tamale Metropolis of Ghana

Fish is an important source of protein all over the world, including in Ghana. The fishery sector plays a major role in meeting the domestic need of animal protein and also contributes greatly in foreign exchange earnings. The domestic supply of fish does not meet the demand, so Ghana imports fish and fish products from other countries. Media reports in Ghana have alleged the use of formaldehyde to preserve fish for increased shelf life and to maintain freshness. This research, therefore, sought to establish the levels of formaldehyde in imported and local fresh fish in the Tamale Metropolis by using a ChemSee formaldehyde and formalin detection test kit. Positive and negative controls were performed by using various concentrations of formalin (1, 10, 30, 50, 100, and 300 ppm) and sterile distilled water, respectively. Three times over a 6-month period, different fish species were obtained from five wholesale cold stores (where fish are sold in cartons) and some local sales points (where locally caught fish are sold). A total of 32 samples were taken during three different sampling sessions: 23 imported fish (mackerel, herring, horse mackerel, salmon, and redfish) and 9 local tilapia. The fish were cut, and 50 g was weighed and blended with an equal volume (50 ml) of sterile distilled water. Samples were transferred to test tubes and centrifuged. A test strip was dipped into the supernatant and observed for a color change. A change in color from white to pink or purple indicated the presence of formaldehyde in fish. The study showed that no formaldehyde was present in the imported and local fish obtained. The appropriate regulatory agencies should carry out this study regularly to ensure that fish consumed in Ghana is safe for consumption.

Efficacy of formalin, iodine and sodium chloride in improvement of egg hatching rate and fry survival prior to the onset of exogenous feeding in yellow perch

Egg disinfection is considered the most important routine work in hatcheries to avoid fungal and/or bacterial infection of fish eggs. The aim of this study was to determine the effectiveness of three disinfectants: formalin, iodine and sodium chloride on the hatching success of yellow perch eggs. The disinfectants were tested in triplicate at different concentrations for 15 and 30 min bath treatments. Two experiments were conducted; formalin at five concentrations (25, 50, 100, 150 and 200 mg L−1) and 25 mg L−1 iodine were tested in the first experiment. The second experiment involved formalin at three concentrations (250, 500 and 1000 mg L−1), iodine at three concentrations (50, 100 and 250 mg L−1) and sodium chloride at three concentrations (500, 1000 and 3000 mg L−1) were used. Iodine and sodium chloride-treated eggs hatched earlier than formalin-treated eggs. The highest mean percentage of eyed stage, hatching rate and survival to first feeding fry was observed at 200 mg L−1 formalin for 30 min, 50 mg L−1 iodine for 15 min and 500 mg L−1 sodium chloride for 30 min. High concentrations of formalin (1000 mg L−1), iodine (250 mg L−1) and sodium chloride (1000 and 3000 mg L−1) showed toxicity to yellow perch eggs, resulting in low hatching rate and survival to first feeding fry. We recommended formalin at a concentration of 150–200 mg L−1 for 30 min as an effective, easily available and low-cost disinfectant for routine use to improve yellow perch hatchability.

Gonadal hormones modulate the responsiveness to local β-blocker-induced antinociception in the temporomandibular joint of male and female rats.

We have previously demonstrated that blockade of β-adrenoreceptors (β-AR) located in the temporomandibular joint (TMJ) of rats suppresses formalin-induced TMJ nociceptive behaviour in both male and female rats, but female rats are more responsive. In this study, we investigated whether gonadal hormones modulate the responsiveness to local β-blocker-induced antinociception in the TMJ of rats. Co-administration of each of the selective β1 (atenolol), β2 (ICI 118.551) and β3 (SR59230A)-AR antagonists with equi-nociceptive concentrations of formalin in the TMJ of intact, gonadectomized and hormone-treated gonadectomized male and female rats. Atenolol, ICI 118.551 and SR59230A significantly reduced formalin-induced TMJ nociception in a dose response fashion in all groups tested. However, a lower dose of each β-AR antagonist was sufficient to significantly reduce nociceptive responses in gonadectomized but not in intact and testosterone-treated gonadectomized male rats. In the female groups, a lower dose of β1 -AR antagonist was sufficient to significantly reduce nociceptive responses in gonadectomized but not in intact or gonadectomized rats treated with progesterone or a high dose of oestradiol; a lower dose of β2 -AR antagonist was sufficient to significantly reduce nociceptive responses in gonadectomized but not in intact and gonadectomized rats treated with low or high dose of oestradiol. Gonadal hormones may reduce the responsiveness to local β-blocker-induced antinociception in the TMJ of male and female rats. However, their effect depends upon their plasma level, the subtype of β-AR and the dose of β-blockers used.

In vitro inactivation of two Egyptian A/H5N1 viruses by four commercial chemical disinfectants.

The highly pathogenic H5N1 avian influenza virus (A/H5N1) devastated the poultry industry and posed a serious health threat. Cleaning and disinfection are essential parts of preventative and postoutbreak management of A/H5N1 infections in poultry. In this preliminary study, we used suspension and carrier tests to evaluate the impact of concentration, time of exposure, surface porosity, and organic matter on the ability of four commercial chemical disinfectants to inactivate two A/H5N1 viruses of clade 2.2.1 isolated in 2006 and 2010 from broiler flocks in Egypt. Viruses were incubated with 0.5%, 1%, and 2% of formalin, glutaraldehyde, TH4, and Virkon S for 15, 30, 60, and 120 min at room temperature (22 +/- 2 C). In suspension tests, in the absence of organic matter, all disinfectants, at each concentration, except Virkon S 0.5%, effectively inactivated virus suspensions after a 15-min exposure time. In the presence of organic matter, the use of low concentrations of formalin (0.5%), glutaraldehyde (0.5%), or Virkon S (0.5%) was not sufficient to inactivate the viruses after 15 min. In gauze carrier tests, only formalin at any concentration for 15 min was sufficient to inactivate the viruses, whereas different concentrations or exposure times were required for glutaraldehyde (0.5% for 60 min), TH4 (0.5% for 30 min), and Virkon S (0.5% for 60 min or 1% for 30 min). In wood carrier tests, total inactivation of the virus was obtained at concentrations of 0.5% for 30 min (formalin and TH4) or 60 min (glutaraldehyde and Virkon S). This study emphasizes the need to use high concentrations of and/or extended time of exposure to disinfectants for efficient inactivation of A/H5N1, particularly in the presence of organic matter or different surfaces, which are common in poultry operations. In addition, it seemed that the virus isolated in 2010 was more resistant to disinfectants than the isolate from 2006 when wood was used as a carrier.

Effects of Sublethal Concentrations of Formalin on the Growth of Clarias gariepinus Fingerlings

Effects of Sublethal Concentrations of Formalin on the Growth of Clarias gariepinus Fingerlings

Influence of copper and formalin on the mycorrhiza of pine (Pinus kesiya Royle ex Gordon)

Various concentrations of copper sulphate and formalin were tested for their effect on the efficiency of mycorrhizal functioning in pine seedlings. Low and higher doses of copper applied to the container grown seedling exhibited a less stimulatory effect than nedium doses. When applied in higher concentrations, the formalin caused mortality in young pine seedlings. The seedling yield and phosphate uptake was found maximum in 100 ppm applied concentration of copper. while słów growth and lower phosphate concentration was observed in the seedlings not given any copper treatment. Formalin at 50 ppm concentration slightly improved the seedling growth and phosphate uptake in mycorrhizal seedling as compared with untreated ones. Variation in the development and spread of ectomycorrhiza on the surface of roots of pine seedlings was also recorded in responses to copper and formalin treatments.

On the suitability of Thiel cadavers for natural orifice transluminal endoscopic surgery (NOTES): surgical training, feasibility studies, and anatomical education.

Surgical training in virtual, animal and cadaver models is essential for minimally invasive surgery. Thiel cadavers are suitable for laparoscopy, but there are few data about the use of embalmed (Tutsch method) and slightly embalmed (Thiel method) cadavers in procedures of Natural Orifice Transluminal Endoscopic Surgery (NOTES), which are usually developed and learned on swine models and fresh frozen cadavers. The aim of this study was thus to assess the use of these cadavers for NOTES approaches. The following surgical procedures were evaluated: transanal total mesorectal excision (four cadavers: one Tutsch, two Thiel, one fresh frozen), transanal ileorectal bypass (five cadavers: one Tutsch, three Thiel, one fresh frozen), and transvaginal appendectomy (two Tutsch cadaver). The Thiel method ensured tissue flexibility and consistency suitable for performing the above surgical procedures with good results and without complications, with only a small increase in rigidity with respect to fresh specimens. Cadavers embalmed with higher formalin concentrations (Tutsch method) were more difficult to use, due to high tissue rigidity and resistance of the abdominal wall to pneumoperitoneum, although NOTES accesses were possible. Thiel cadavers are suitable for transanal/transrectal and transvaginal NOTES approaches, for training surgical residents/specialists and also for surgical research. In minimally invasive surgery (and particularly in NOTES), integration between cadaver (fresh frozen and/or Thiel) and animal models would represent the gold standard, allowing guaranteed knowledge of and respect for human surgical anatomy and correct management of surgery on living subjects. NOTES approaches to human cadavers may also be proposed for the anatomical education of medical students.

Minimum effective concentrations of formalin and sodium percarbonate on the free-living stages of an Australian isolate of Ichthyophthirius multifiliis.

Ichthyophthirius multifiliis Fouquet, 1876, a ciliate protozoan, is a common cosmopolitan parasite of freshwater teleosts and is a recurring problem during the summer months on Australian rainbow trout Oncorhynchus mykiss (Walbaum, 1792) farms. Preventative strategies include increasing water flow and filtration, but when an infection is established, chemical intervention is often required. Formalin (FOR) has been traditionally used on Australian trout farms as a treatment for I. multifiliis. Treatment using sodium percarbonate (SPC) that releases hydrogen peroxide when dissolved is being implemented on a number of farms. To assess anecdotal reports of low efficacy we evaluated 1 h exposures of FOR and SPC at 12 °C and 17 °C in both hard and soft water against free-living stages of I. multifiliis. Each free-living stage were exposed to FOR and SPC in vitro; theronts were exposed to 8, 16, 32 or 64 mg/l SPC or FOR every 15 min, for a maximum of 6 h, and the number of live theronts at each time point was recorded. Prototomonts and tomocysts were exposed to 64, 128, 256 and 512 mg/l SPC and 16, 32, 64 and 128 mg/l FOR for 1 h, incubated, with the percentage viability and the number of theronts produced recorded. Theronts were more sensitive to treatment than tomonts, and prototomonts were more sensitive to treatment than tomocysts. FOR and SPC killed all theronts within 15 min at 64 mg/l at both temperatures. FOR was effective against all prototomonts at ≥64 mg/l at both temperatures and was effective against all tomocysts at 128 mg/l at 17 °C but did not achieve complete mortality in any doses tested at 12 °C. SPC was effective against prototomonts and tomocysts at 64 m/l at 17 °C but required ≥256 mg/l at 12 °C. These results can be used to aid development of specific treatment strategies for the management of I. multifiliis on Australian rainbow trout farms.

Gill histopathological characteristics of Caspian roach (Rutilus rutilus caspicus) fingerlings treated with potassium permanganate and formalin

The aim of this study was to determine the gill histopathological characteristics of Caspian roach (Rutilus rutilus caspicus) fingerlings exposed to different concentrations of potassium permanganate (PM) and formalin (FO). The fish were exposed to different PM and FO concentrations over different periods: 1 ppm PM for 24 h (1-P24), 2 ppm PM for 24 h (2-P24), 5 ppm PM for 0.5 h (5-P0.5), 10 ppm PM for 0.5 h (10-P0.5), 10 ppm FO for 24 h (10-F24), 20 ppm FO for 24 h (20-F24), 40 ppm FO for 0.5 h (40-F0.5) and 80 ppm FO for 0.5 h (80-F0.5). After exposure, gill samples were collected for histological examination. The most frequent gill histopathological symptoms were hyperplasia and epithelial lifting. The order of the gill injury index (Ig.i) among the treatments was as follow: 1-P24, 2-P24 < 5-P0.5, 40-F0.5 < 10-F24 < 10-P0.5, 20-F24, 80-F0.5. Comparing the two agents, it is concluded that there is no significant difference in the gill damages between the agents during the short-bath treatments. However, PM causes less pathological symptoms than FO during the long-bath treatments. Comparing the bath durations, the agents showed different behaviours. PM-treated fish showed significantly lower gill damage during the long-bath compared to the short-bath treatment; whereas, pathological symptoms of FO-treated fish was dose-dependent for each exposure period, separately. Overall, exposure of Caspian roach to PM, at the concentrations recommended for long bath, resulted in milder gill damages compared to FO.

Development and Preclinical Evaluation of a Trivalent, Formalin-Inactivated Shigella Whole-Cell Vaccine

Studies were undertaken to manufacture a multivalent Shigella inactivated whole-cell vaccine that is safe, effective, and inexpensive. By using several formalin concentrations, temperatures, and incubation periods, an optimized set of inactivation conditions was established for Shigella flexneri 2a, S. sonnei, and S. flexneri 3a to produce inactivated whole cells expressing a full repertoire of Ipa proteins and lipopolysaccharide (LPS). The inactivation conditions selected were treatment with 0.2% formalin (S. flexneri 2a and 3a) or 0.6% formalin (S. sonnei) for 48 h at 25°C. Vaccine formulations prepared under different inactivation conditions, in different doses (10E5, 10E7, and 10E9 cells), and with or without the inclusion of double-mutant heat-labile toxin (dmLT) were evaluated in mice. Two intranasal immunizations with ≥10E7 inactivated whole cells resulted in high levels of anti-Invaplex and moderate levels of LPS-specific IgG and IgA in serum and in lung and intestinal wash samples. Addition of dmLT to the vaccine formulations did not significantly enhance humoral immunogenicity. Minimal humoral responses for IpaB, IpaC, or IpaD were detected after immunization with inactivated whole Shigella cells regardless of the vaccine inactivation conditions. In guinea pigs, monovalent formulations of S. flexneri 2a of 3a or S. sonnei consisting of 10E8, 10E9, or 10E10 cells were protective in a keratoconjunctivitis assay. A trivalent formulation provided protection against all three serotypes (S. flexneri 2a, P = 0.018; S. flexneri 3a, P = 0.04; S. sonnei, P < 0.0001). The inactivated Shigella whole-cell vaccine approach incorporates an uncomplicated manufacturing process that is compatible with multivalency and the future development of a broadly protective Shigella vaccine.

Low Formalin Concentrations Induce Fine-Tuned Responses That Are Sex and Age-Dependent: A Developmental Study

The formalin test is increasingly applied as a model of inflammatory pain using high formalin concentrations (5–15%). However, little is known about the effects of low formalin concentrations on related behavioural responses. To examine this, rat pups were subjected to various concentrations of formalin at four developmental stages: 7, 13, 22, and 82 days of age. At postnatal day (PND) 7, sex differences in flinching but not licking responses were observed with 0.5% formalin evoking higher flinching in males than in females. A dose response was evident in that 0.5% formalin also produced higher licking responses compared to 0.3% or 0.4% formalin. At PND 13, a concentration of 0.8% formalin evoked a biphasic response. At PND 22, a concentration of 1.1% evoked higher flinching and licking responses during the late phase (10–30 min) in both males and females. During the early phase (0–5 min), 1.1% evoked higher licking responses compared to 0.9% or 1% formalin. 1.1% formalin produced a biphasic response that was not evident with 0.9 or 1%. At PND 82, rats displayed a biphasic pattern in response to three formalin concentrations (1.25%, 1.75% and 2.25%) with the presence of an interphase for both 1.75% and 2.25% but not for 1.25%. These data suggest that low formalin concentrations induce fine-tuned responses that are not apparent with the high formalin concentration commonly used in the formalin test. These data also show that the developing nociceptive system is very sensitive to subtle changes in formalin concentrations.

Plastinated knee specimens: a novel educational tool.

During the routine dissection of knee joints in an anatomy dissection hall, it was observed that the specimens had deteriorated overtime, due to their repeated handling and the use of high concentrations of formalin for their fixation. In order to stop their further deterioration, we decided to plastinate these specimens. Thus, the present study was undertaken to prepare plastinated knee specimens from old embalmed cadavers and to compare them with freshly fixed, plastinated specimens. 1. To plastinate old embalmed and fresh formalin fixed knee regions.2. To demonstrate the extra and the intracapsular structures around both the plastinated knee regions.3. To compare their morphological features in terms of their colours, dilatation and flexibility. A total of 15 knee joint specimens from among fresh formalin (5-8%) fixed (group I) and old embalmed bodies (group II) were collected, washed and plastinated by using the standard S-10 silicon technique and they were compared for their colours, dilatation and flexibility. All the plastinated specimens showed an accurate reproduction of the tissue details that were comparable to those of the natural unfixed specimens. A comparison among the two groups showed a significant difference in terms of the colour, dilatation and the flexibility of the specimens. The plastinated knee joint specimens from group I were of good quality, with negligible shrinkage, more flexibility and well preserved morphologies. Plastinated knee specimens can serve as an excellent educational tool for the undergraduate and postgraduate students of anatomy, radiology and orthopaedics, as they are dry, odourless and nontoxic, with a good structural preservation and a higher instructional value. The fresh knee regions, when they were plastinated, were aesthetically superior in terms of their colours, dilatation and flexibility, thus making them ideal for teaching and hands-on experiences.