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PubMed1981

A quantitative regional analysis of protein synthesis inhibition in the rat brain following localized injection of cycloheximide.

Previous work has shown that bilateral injection of as little as 10 microgram of cycloheximide (CHX) into the amygdala, but not into the internal capsule, caused a time-dependent disruption of long-term retention of passive avoidance training. Under these conditions, protein synthesis in the entire brain was inhibited by less than 10%. The present study was undertaken to quantify the resulting inhibition of protein synthesis in various brain regions (amygdala, internal capsule, caudate, cortex, hippocampus, thalamus, hypothalamus and the entire half brain). Rats were subcutaneously injected with L-[14C-methyl]methionine following unilateral administration of CHX via a cannula implanted in either the amygdala or the internal capsule. Regional inhibition of protein synthesis was determined by analysis of autoradiograms from different brain levels using an image analyzing computer to measure the optical densities of microscopic areas corresponding to discrete neuroanatomical structures. Regional patterns of inhibition were assessed: (a) after injection of different doses of CHX (10 or 20 microgram) into the amygdala; (b) after injection of 20 microgram of CHX into the amygdala or internal capsule; and (c) at different times (0.5, 3, 6 and 24 h) after injection of 20 microgram of CHX into the amygdala. Quantitative results are presented for the temporal and spatial patterns of protein synthesis inhibition caused by CHX injection. Since injection of CHX into the amygdala resulted in a profound inhibition of protein synthesis in both the amygdala and internal capsule while injection into the thermal capsule only caused a marked inhibition in the capsule itself, these results provide a possible explanation for our earlier observation that injection of CHX into the amygdala produced a retention deficit while injection into the adjacent internal capsule had no effect on memory function. These observations on protein synthesis inhibition support our earlier hypothesis that CHX injected into the amygdala might impair memory by virtue of its action on amygdaloid function rather than as a result of its effect on the brain as a whole.

Amygdala↗
PubMed1996

Antinociceptive effects of repeated systemic injections of calcitonin in formalin-induced hyperalgesic rats.

Calcitonin (CT) produces long-lasting analgesia in patients suffering from painful diseases following repeated systemic injections, but there have been only a few contradictory reports on the antinociceptive action of systemic injections of CTs in animal experiments. This study was conducted to elucidate an antinociceptive action of systemic CT in rats. An injection of dilute formalin induced hyperalgesia for about 2 h. Single topical injections of 0.12 and 1.2 U, but not 0.012 U, of [Asu1.7] eel CT (eCT) into the same site of formalin injection inhibited the hyperalgesia. Repeated systemic injections of eCT (4 and 40, but not 0.4, U kg-1 day-1) for 7 days inhibited the hyperalgesia, while the single injection was without effects at doses tested. Although the highest dose of eCT (40 U kg-1 day-1) inhibited an increase in body weight following repeated injections, lower doses (0.4 and 4 U kg-1 day-1) were without effects. The suppression of hyperalgesia following repeated systemic injections of eCT (4 U kg-1 day-1) lasted for at least 24 h, and subsided by 3 days following the last eCT injection. These results indicate that the repeated systemic injections of eCT produce a long-lasting inhibition of formalin-induced hyperalgesia in rats. This inhibitory effect is similar to CT analgesia in human subjects in terms of a necessity for repeated administration, effective dose and long-lasting effects.

Analgesics↗
PubMed1984

Deficits in locomotor behaviour and thermoregulation produced by intrahypothalamic dopamine injections.

When nigrostriatal dopamine neurones degenerate, a loss of functional dopamine in the striatum occurs and is accompanied by increased dopamine in the degenerating axons which traverse the hypothalamus. While the behavioural deficits which occur after nigrostriatal degeneration have been attributed to the loss of functional dopamine neurotransmission, evidence produced by us suggests that the increased levels of amines in the degenerating axons may be neuroactive and participate in the production of these behavioural deficits. To test this hypothesis further, albino rats were injected bilaterally with 200 nmol of dopamine in a location just rostral to the diencephalon/mesencephalon border, where amine accumulation is commonly observed following lateral hypothalamic damage. The effect of these injections upon open field performance, thermoregulation and motor reflex control was determined 40 min after dopamine injection. In a second study, pargyline (15 mg/kg. i.p.) was administered 30 min before intracerebral dopamine to determine whether this treatment would increase the severity of motor and thermoregulatory deficits which occurred after dopamine injections alone. Deficits in locomotion, rearing and the ability to regulate body temperature were seen after the dopamine injections while motor reflex control in these animals was similar to that seen in vehicle-injected controls. The behavioural deficits displayed by pargyline pretreated, dopamine injected animals were slightly but not significantly more severe than those displayed by animals receiving dopamine injections alone. Fluorescent histochemical assessment of injection sites revealed that dopamine injection produced an increase in fluorescence or "amine accumulation" at the site of injection but this was considerably less than that seen after catecholamine degeneration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2006

Nuclear and cytoskeletal dynamics during oocyte maturation and development of somatic cell cloned pig embryos injected with membrane disintegrated donor cells.

The objectives of this study were to characterize the nuclear and cytoskeletal changes of pig oocytes during in vitro maturation (IVM) and the development of the reconstructed embryos after injection with membrane intact or disintegrated donor cells. Cumulus-oocyte complexes (COCs) were collected from abattoir ovaries by follicle (2-8mm) aspiration. In Experiment 1, COCs were cultured in NCSU-23 medium for 0, 11, 22, 33, and 44 h. Oocytes were fixed at different time points for nuclear and cytoskeletal labeling. Forty-three percent and 75% oocytes progressed to MII stage at 33 and 44 h after IVM culture, respectively. Dynamic shift of spindle and cytoplasmic microtubules was evident. In Experiment 2, matured oocytes were injected with either the whole cumulus cell with or without intact cell membranes after enucleation. The reconstructed oocytes were fixed at 0, 2, or 4 h after cell injection for nuclear and cytoskeletal evaluation. When an intact cumulus cell was injected, the injected cell remained intact within 4h after injection. When a cell with disintegrated membrane was injected, 59-63% (n=146) of the injected cell underwent premature chromosome condensation (PCC). In Experiment 3, the reconstructed pig oocytes received membrane-disintegrated cumulus cells or fetal fibroblasts were cultured in PZM medium. The blastocyst rate of the fibroblast-injected embryos was 10%, which was lower than the non-cloned parthenotes (33%, P<0.05) but higher than the cumulus cell-injected embryos (2.7%). These results suggest that pig oocytes are subjected to nuclear and cytoskeletal reorganization during maturation. Pig oocytes injected with membrane-disintegrated fibroblast cells support better blastocyst development of the cloned embryos.

Animals↗
PubMed2005

Risk profile of individuals who provide assistance with illicit drug injections.

BACKGROUND: Assisted injection is a common practice among injection drug users (IDU) that carries significant risk for health-related harm. However, little is known about the individuals who provide assistance with injections. METHODS: We evaluated factors associated with providing help injecting among participants enrolled in the Vancouver Injection Drug User Study (VIDUS) using univariate and logistic regression analyses. We also examined self-reported relationships between the provider and the receiver of assisted injection, if compensation was provided for assistance, and what type of compensation was given. RESULTS: Of the 704 IDU eligible for this analysis, 193 (27.4%) had provided help injecting during the last 6 months. Variables independently associated with providing help injecting included: lending one's own syringe (adjusted odds ratio [AOR] = 3.99, p = 0.004); frequent heroin injection (AOR = 3.75, p < 0.001); unstable housing (AOR = 2.15, p < 0.001); binge drug use (AOR = 2.01, p = 0.012); frequent cocaine injection (AOR = 1.95, p = 0.002); and frequent use of crack cocaine (AOR = 1.85, p = 0.002). Help was most often provided to a casual (47.2%) or a close friend (41.5%). Of the 96 (49.7%) individuals who received compensation for providing help, the most common forms of compensation were drugs (89.6%) and money (45.8%). CONCLUSION: Providing help injecting was common among IDU in this cohort and was associated with various high-risk behaviours, including elevated levels of syringe lending. These findings indicate the need for interventions that offset the risks associated with this dangerous practice.

Adult↗
PubMed2004

Displacement and sweep efficiencies in a DNAPL recovery test using micellar and polymer solutions injected in a five-spot pattern.

Soil washing with micellar solutions is a promising alternative for the remediation of DNAPL source zones. As with any flushing technology, the success of soil washing with micellar solutions depends in a very large part on the ability of the solution to contact the contaminant (sweep efficiency) and then on the efficiency of contaminant removal once this contact is made (displacement efficiency). We report here on a field test where a micellar solution was used to recover a DNAPL in an open five-spot pattern in which polymer solutions were also injected before and after the washing solution to improve sweep efficiency. The washing solution formulation was optimised in the laboratory prior to the test to obtain good dissolution capacity. For a high-concentration and low-volume soil flushing remediation test such as the one performed (0.8 pore volumes of actual washing solution injected), slug sizing of the washing solution is critical. It was evaluated by an analytical solution. In a five-spot pattern, the displacement efficiency of the washing solution was observed to vary in the porous medium as a function of the radial distance from the injection well because: (1) the volume of the washing solution flowing through a section of the test cell changes (maximum close to the injection well and minimal at the pumping wells); (2) the in situ velocity changes (maximum at the wells and minimum between the wells) and; (3) the contact time of the washing solution with the NAPL changes as a function of the distance from the injection well. The relative importance of the recovery mechanisms, mobilisation and dissolution, was also observed to vary in the test cell. The reduced velocity increased the contact time of the washing solution with the DNAPL enhancing its dissolution, but the decrease of the capillary number caused less mobilisation. The washing process is much more extensive around the injection well. The use of an injection-pumping pattern allowing a complete sweep of the remediated area is essential. Following a comprehensive characterisation, modeling is an efficient tool to design the injection-pumping scheme and to optimise injection and pumping rates providing the best areal sweep. The vertical sweep can be controlled by using a polymer solution (Xanthan gum). The polymer solution also has a positive effect on front stability between the solutions injected. The injection rate of the polymer solution that follows the washing solution must be kept minimal initially to prevent dilution of the washing solution by fingering.

Kinetics↗
PubMed2005

Injection of innocuous oils to create reactive barriers for bioremediation: laboratory studies.

In situ groundwater remediation may be achieved using stationary permeable barriers created by the injection of a substrate, such as innocuous vegetable oil, into the contaminated aquifer. The oil provides the electron donor stimulating microorganisms to degrade or sequester many contaminants. At present, little is known about the best procedures to use when injecting oil into an aquifer. In this investigation, laboratory column and sand tank studies were used as model systems to explore the effect of different injection parameters on the distribution of oil emulsions into water-saturated sand. The parameters investigated included injection pressures of 70, 1400 and 18,000 KPa; injection times of 15, 30, 60 or 120 s; and the influence of an emulsifier, polyoxyethylenesorbitan monooleate (Tween 80), upon the distribution of the injected oil. The longest injection patterns were achieved at 18,000 KPa. A pattern that was 46+/-1.8 cm long was produced with an 18,000 KPa injection for 60 s. Increasing the injection time to 120 s increased the length of the pattern by only 6.5%. Tween 80 at concentrations of 0.05% increased the width of the injection patterns but did not increase the length of the pattern. A multi-ported injection probe might be used to create in situ permeable barriers approximately 1 m wide.

Bacteria↗
PubMed2006

Field test of a cross-injection scheme for stimulating in situ denitrification near a municipal water supply well.

A pilot-scale test of an in situ denitrification scheme was undertaken to assess an adaptation of the nutrient injection wall (NIW) technology for treating a deep (30-40 m) nitrate contamination problem (N-NO(-)(3) ~ 10-12 mg/L). The adaptation is called the Cross-Injection Scheme (CIS). It duplicates the NIW method without a wall; wells are installed and operated directly in the aquifer and high-flux zones of the aquifer are preferentially targeted for treatment. The test was conducted on the site of a municipal water supply well field, with the supply well pumping between 15-80 m(3)/h. Acetate was periodically injected into the aquifer between an injection-extraction well pair positioned across the normal direction of flow. The injected pulses were then permitted to move with the water toward the municipal wells, providing a carbon supply to drive the desired denitrification. The fate of nitrate, nitrite, acetate and sulphate were monitored at multilevel wells located between the injection location and the municipal wells. The acetate pulsing interval was approximately weekly (9 h injections), so that the system was operating passively 95% of the time. Previous work on the site has established that the highest solute fluxes were associated with a 1-3 m thick zone about 35 m below surface. This zone was found to respond to the acetate additions as a function of the municipal pumping rate and the carbon-to-nitrogen ratio (i.e., determined by the injected acetate concentration). Initially, acetate was injected just below the theoretical stoichiometric requirement for complete denitrification and nitrate disappearance was accompanied by nitrite production. Increasing the C:N ratio (doubling the acetate injection concentration) increased the removal of nitrate and diminished the occurrence of nitrite. Slowing the municipal pumping rate, with a C:N ratio of 1.2-1.6, resulted in complete nitrate attenuation with no nitrite production and no sulfate reduction. The experiment demonstrated that the CIS injection scheme is a viable option for the treatment of nitrate contamination in situ near high-capacity wells.

Acetates↗
PubMed1999

Delayed behavioral effects following intrahippocampal injection of aggregated A beta (1-42).

Beta amyloid protein (A beta) is the major extracellular component of Alzheimer's disease (AD) plaques. In the current study, A beta (1-42) was aggregated in vitro using a method which produces A beta aggregates similar to those found in the AD brain. Twelve male Sprague-Dawley rats were trained in two-lever operant chambers under an alternating lever cyclic-ratio (ALCR) schedule. When performance was stable on the ALCR schedule, six subjects were injected (bilaterally into the CA3 area of the dorsal hippocampus) with 5.0 microliters aggregated A beta in suspension, and the remaining six subjects were injected with 5.0 microliters sterile water. Behavioral testing resumed 5 days after surgery and continued for 90 days post-injection. Aggregated A beta injection did not affect the number of lever switching errors made in a daily session but did affect the number of incorrect lever response perseverations. After approximately 30 days post-injection, aggregated A beta injection detrimentally affected ability to track the changing parameters of the schedule, and decreased the efficiency by which subjects obtained reinforcers. From approximately day 50 post-injection onward, A beta-injected subjects demonstrated significantly higher numbers of incorrect lever response perseverations than did sterile water-injected subjects. These effects appeared to be central rather than peripheral, as A beta injection did not decrease running response rates under the ALCR schedule. The delayed onset of behavioral effects seen in this and other behavioral studies may be a result of a cascade of potentially harmful responses induced through glial activation following aggregated A beta injection.

Amyloid beta-Peptides↗
PubMedDate not supplied

Hemostatic effect of local intramural injection of dehydrated ethanol in the canine gastrointestinal tract.

The relative value of a subserosal injection of 98% ethanol (0.2 ml x 4) in controlling acute and chronic bleeding from serosal vessels was assessed in 17 dogs. Blood flow was measured from gastric serosal vessels (average diameter, 1.6 mm) severed immediately after, 24 hours after, and 48 hours after ethanol injection. Blood flow from severed colonic serosal vessels (averaging diameter, 1.0 mm) was measured before and immediately after ethanol injection. The safety of ethanol injection was tested by endoscopically guided submucosal injections which were sequentially observed by endoscopy at 1 hour, 24 hours, and weekly for 4 weeks after injection. Ethanol injection had no effect on bleeding from larger gastric vessels unless the injection was made 24 or 48 hours prior to vessel severence. Ethanol injection was effective in reducing bleeding from the smaller colonic vessels when done immediately prior to vessel severence. Gastric submucosal injections led to ulcers which extended into the muscle layer at 1 week and were completely healed by 3 weeks; none perforated or bled. These data support the potential efficacy of therapeutic ethanol injection for the control of small vessel (1.0 mm in diameter) bleeding and the potential prophylactic value against rebleeding from larger vessels. Further studies are needed to determine whether these findings are organ related as opposed to being diameter specific.

Animals↗
PubMed1998

Randomized controlled studies of injection Gold Probes compared with monotherapies for hemostasis of bleeding canine gastric ulcers.

BACKGROUND: There is a significant interest in combination therapy using endoscopic epinephrine injection and thermal coagulation for nonvariceal hemostasis. The purpose of the study was to compare the relative effectiveness, ease of use, and safety of new Injection Gold Probes to other hemostasis techniques in three randomized, controlled laboratory studies of bleeding canine gastric ulcers. METHODS: Fifteen dogs with prehepatic portal hypertension were heparinized and bleeding gastric ulcers were induced with jumbo biopsy forceps. Three different prototypes of Injection Gold Probes were compared with monotherapy (thermal, electrocoagulation, or epinephrine injection alone), control, or combination therapy with separate injector and thermal probes. The treatment times, total number of pulses or injections, volume of epinephrine injected, and ease of applications were recorded. Gastric ulcer size, ulcer healing, and complications were evaluated at 1 and 4 weeks. RESULTS: All endoscopic treatments were effective for acute hemostasis compared with control. Thermal coagulation alone was the fastest treatment to perform. The performance of the first Injection Gold Probe prototype was restricted by its small-gauge needle. The second and third Injection Gold Probe prototypes had a larger-gauge needle and irrigation channel which made them faster and easier to use than separate injection catheters and thermal probes. CONCLUSIONS: The advantages of Injection Gold Probes were the ability to irrigate, inject, and coagulate without probe removal. Combination therapy did not increase treatment-related complications compared with monotherapies.

Animals↗
PubMed2001

Performance of programmed temperature vaporizer, pulsed splitless and on-column injection techniques in analysis of pesticide residues in plant matrices.

A programmed temperature vaporizer (PTV) injection technique has been recently implemented in our laboratory. In present paper its performance is compared with other GC injection techniques commonly used in trace analysis of organic contaminants. Twenty-six pesticides representing different chemical classes were selected for the study. This group comprised compounds typically subjected to discrimination in the injection port of the gas chromatograph, e.g., polar organophosphorus pesticides and thermolabile carbamates. In the first set of experiments standards in pure solvent were injected into GC systems employing different types of injection, i.e., (i) on-column, (ii) pulsed splitless, (iii) PTV solvent split, (iv) PTV splitless, and the responses of analytes were compared. Discrimination of troublesome compounds was significantly decreased with the application of PTV solvent split injection. In the second set of experiments repetitive injections of purified wheat samples were performed, with aims to evaluate the long-term stability of responses, as well as matrix effects in different stages of system contamination for each injection technique. The tolerance of the GC system to co-injected matrix components was increased in the order: on-column<pulsed splitless<PTV solvent split technique. As regards matrix effects, these were suppressed considerably with the PTV solvent split technique in comparison with pulsed splitless injection. With the latter technique after 66 injections of wheat samples relative responses (apparent recovery) reached as much as 450% for some compounds, while with the application of PTV matrix effects did not exceed 200% under the same conditions.

Chromatography, Gas↗
PubMed2003

Unilateral carrageenan injection into muscle or joint induces chronic bilateral hyperalgesia in rats.

Chronic musculoskeletal pain is a major clinical problem and there is a general lack of animal models to study this condition. Carrageenan is commonly used to produce short-lasting acute inflammation and hyperalgesia in animal models. However, the potential of carrageenan to produce chronic, long-lasting hyperalgesia has not been evaluated. In the present study, we investigated the long-term effects of carrageenan injected into joint or muscle in rats. Rats were injected with 0.3, 1 or 3% carrageenan in one knee joint or gastrocnemius muscle and hyperalgesia to mechanical (measured as decreased withdrawal threshold) and heat (measured as decreased withdrawal latency) stimuli of both paws assessed before and at varying times after injection, through 8 weeks. Histological changes were examined only after injection of 3% carrageenan. Three percent carrageenan injected in the muscle or knee produced hyperalgesia to mechanical and heat stimuli ipsilaterally, which lasted 7-8 weeks and spread to the contralateral side 1-2 weeks after injection. One percent carrageenan injected to the knee joint or gastrocnemius muscle, produced hyperalgesia that was shorter-lasting and remained ipsilateral; 0.3% carrageenan injected into the knee joint or gastrocnemius muscle had no effect. Three percent carrageenan injected into the skin surrounding the knee joint did not produce hyperalgesia. A similar pattern of inflammatory changes was observed histologically for both the joint and muscle tissues. Acute inflammation was observed for the first 24 h with edema and neutrophilic infiltration evident as early as 4 h. At 1 week, the inflammation converted to primarily a macrophage response with scattered mast cells. The data suggest that animals injected with 1 or 3% carrageenan in the knee joint or gastrocnemius muscle could be used as models of acute inflammation through 24 h and chronic inflammation after 1 week. Furthermore, 3% carrageenan injected into deep tissues produces hyperalgesia that spreads to the contralateral side, at the same time period as the inflammation transforms from acute to chronic.

Animals↗
PubMed2001

Correlation of increased grooming behavior and motor activity with alterations in nigrostriatal and mesolimbic catecholamines after alpha-melanotropin and neuropeptide glutamine-isoleucine injection in the rat ventral tegmental area.

1. We wished to further study the behavioral effects of alpha-melanotropin (alpha-MSH), melanin-concentrating hormone (MCH), and neuropeptide glutamine-isoleucine (NEI). 2. To this effect we administered alpha-MSH, MCH, and NEI in the ventral tegmental area of the rat, a structure where these neuropeptides are highly concentrated. To further elucidate the biochemical mechanisms of the behavioral effect of these neuropeptides, we determined the degree of grooming behavior and the levels of catecholamines. after neuropeptide administration. 3. We preselected those animals responding to the central injection of alpha-MSH with excessive grooming behavior. We administered the neuropeptides at the dose of 1 microg/0.5 microL, in each side of the ventral tegmental area, bilaterally. We studied grooming behavior, locomotor activity, and total behavior scores, 30 and 65 min after administration of the peptides. 4. Three groups of animals were decapitated immediately after the injection of the neuropeptides, and 30 or 65 min after injection. We measured dopamine (DA), noradrenaline (NA), and the dopac/dopamine ratio (DOPAC/DA) to determine steady state levels of catecholamines and an indirect measure of DA release and metabolism, respectively. 5. Injections of alpha-MSH produced significant elevations in grooming behavior, locomotor activity, and total behavior scores, both 30 and 65 min after peptide administration. This was correlated with significant decreases in DA content, increases in DOPAC content, and increases in the DOPAC/DA ratio. In the caudate putamen, changes in catecholamines occurred both at 30 and 65 min after injection. In the nucleus accumbens, changes were present at 65 min after injection. Conversely, there were no alterations in NA content, either in the caudate putamen or in the nucleus accumbens, at any time after the injection. 6. Injections of NEI resulted in significant elevations in grooming behavior, locomotor activity, and total behavior scores, both 30 and 65 min after peptide administration. This was correlated with increased DOPAC/DA ratio in the nucleus caudatus but not in the nucleus accumbens. Conversely, NEI produced increased NA concentrations in the nucleus accumbens, but not in the nucleus caudatus. 7. Injections of MCH did not produce significant changes in behavior or significant changes in nucleus caudatus or nucleus accumbens catecholamines. 8. Our results indicate (a) There is a correlation with alterations in behavior as induced for the neuropeptides injected here, and changes in extrapyramidal catecholamines. (b) There is a correlation between alterations in behavior and increases in DOPAC/DA ratio in the nucleus caudatus. (c) There is a correlation between alterations in behavior and alterations in catecholamines in the nucleus accumbens. In the nucleus accumbens, DOPAC/DA ratio is changed after alpha-MSH, and NA ratio is changed after NEI injection. (d) Absence of alterations in extrapyramidal catecholamines, and in particular in catecholamines in the nucleus accumbens, correlates with absence of behavioral alterations after neuropeptide administration to the ventral tegmental area. 9. In conclusion, the behavioral effect of exogenous administration of neuropeptides in the ventral tegmental area is peptide-specific, and is probably associated with alterations in catecholamine metabolism and release in the nucleus caudatus and the nucleus accumbens. Both alpha-MSH and NEI seem to stimulate the nigrostriatal DA system. While alpha-MSH appears to stimulate the mesolimbic DA system as well, NEI may exert its actions not through the DA, but through the NA mesolimbic system. The precise contribution of DA and NA, and the relative role of the nucleus caudatus and nucleus accumbens in these behaviors remain to be elucidated.

Animals↗
PubMed2000

Thinner needles do not influence injection pain, insulin leakage or bleeding in children and adolescents with type 1 diabetes.

AIMS: To investigate pain, leakage and bleeding when injecting insulin with different diameters of needles. METHODS: Sixty children and adolescents aged 9-21 yrs participated in study A and 40 aged 8-20 yrs in study B. Both were double-blind and randomized. In study A, we evaluated the pain when injecting with three needles [Novo 27G/13 mm (N27), B-D MicroFine IV 28G/13 mm (B28), NovoFine 28G/12 mm (N28)] and in study B, with three needles [NovoFine 28G/12 mm (N28), B-D MicroFine+ 29G/13 mm (B29), NovoFine 30G/8 mm (N30)] and one placebo injection (no needle mounted). Abdominal and thigh injections were given in a 45 degrees angle with a lifted two-finger skinfold on two different visits, scoring pain on a 10-cm visual analog scale (VAS), and in study B faces were added to the scale. RESULTS: The median VAS scores in study A were 1.2 cm (N27), 1.2 cm (B28) and 1.0 cm (N28) for abdominal injections, and 1.2 cm (N27), 0.7 cm (B28) and 1.1 cm (N28) (n.s.) for thigh injections. The median VAS scores in study B were 2.5 cm (N28), 2.3 cm (B29) and 2.8 cm (N30) (n.s.) for abdominal injections, and 2.0 cm (N28), 1.5 cm (B29) and 1.9 cm (N30) (n.s.) for thigh injections. The overall median score of placebo injections was 0.1 cm (p=0.0001). Bleedings were less common with the B29 needle (35.5%) than with the N28 needle (48.1%) (p=0.028) but with no difference compared to the N30 needle (39.2%). Leakage of insulin was found in 14% of abdominal and 25% of thigh injections (p=0.0001) with no difference between the needles. VAS scores were higher in study B which may be explained by the facial VAS scale increasing the range of answers. CONCLUSIONS: We found no difference in injection pain, preference, bleeding or insulin leakage between the needles. Decreasing the needle diameter from 0.4 to 0.3 mm (27-30G) does not seem to decrease pain perception in this age group.

Clinical Trial↗
PubMed2001

Unsafe injecting practices among attendees of syringe exchange programmes in France.

AIMS: To describe syringe exchange programme attendees and their injection practices. DESIGN: Cross-sectional study (one week in 1998). Data were collected through a standardized questionnaire. SETTING: 60/74 syringe exchange programmes (SEPs) in France. PARTICIPANTS: Clients requesting syringes in 60 SEPs. MEASUREMENTS: Self-reports of drug use, injecting behaviour, sexual behaviour, serological status (HIV, HBV, HCV). Prevalence of unsafe injecting practices in the previous month such as: syringe sharing; and sharing other injection paraphernalia. FINDINGS: 1004 questionnaires were collected (response rate: 50%). The mean age of respondents was 30 years, and 70% were males. Among individuals tested, HIV reported prevalence was 19.2%, HCV 58.4% and HBV 20.8%. The mean duration of drug use was 11 years. Eighty-five percent were polydrug users and buprenorphine high-dosage was the substance most used (73%). In the previous month, 45% of the participants had re-used a syringe, 93% injected at least daily (mean 3.6 injections per day), 18% shared a syringe and 71% shared injection paraphernalia. In multivariate analyses, unsafe injecting practices were associated with heroin and cocaine use and with living in a couple. The cluster analysis identified five categories of IDUs: users of buprenorphine-HD (45% of the responders), morphine-sulphate (17%), benzodiazepines and other legal drugs (13%), methadone associated with other legal drugs (13%) and crack-cocaine (13%). The buprenorphine-HD group had better social status and safer injection practices. CONCLUSIONS: In France, despite an increase in the accessibility to syringes and substitution treatments, unsafe injecting practices persist among SEP attenders. Interventions should stress the importance of using sterile material for each injection, even with a steady sex partner.

Adult↗
PubMed2001

Long-lasting inflammation and long-term hyperalgesia after subcutaneous formalin injection into the rat hindpaw.

Subcutaneous formalin injection is widely used as a nociceptive stimulus in the rat. This procedure evokes overt behaviors that last about 90 minutes. However, little is known about the duration of paw inflammation and alterations in pain sensitivity to noxious stimuli after 2 hours. We studied the nociceptive responses to thermal and mechanical stimuli 2 hours to 4 weeks after formalin injection into the dorsal or plantar side of the hindpaw. Thirty-two adult male Sprague-Dawley rats were divided into 3 groups: In group I, 50 microL of 5% formalin was injected into the plantar side (n = 12); in group II, 50 microL of 5% formalin was injected into the dorsal side (n = 12); in group III, 50 microL saline was injected into the dorsal or plantar side of the hindpaw (n = 8). Nociceptive responses to thermal and mechanical stimuli applied to the dorsal or plantar surfaces of the injected and the contralateral hindpaws were recorded. The injection of formalin into the rat's hindpaw produced a hypoalgesic region around the injection site. In contrast, hyperalgesic responses to thermal and mechanical stimulation were induced on the opposite surface of the injected hindpaw as well as in the contralateral noninjected hindpaw. The hyperalgesic responses, which were observed 2 hours after formalin administration, were enhanced 1 to 3 days after injection and lasted 3 to 4 weeks. These results suggest that peripheral inflammation after subcutaneous formalin injection produces a long-lasting sensitization. Possible mechanisms for these changes in nociception are discussed.

Journal Article↗
PubMed1996

"Just using old works": injecting risk behaviour in prison.

A minority of injecting drug users engage in high risk injecting behaviours when in prison. In the United Kingdom between a quarter and a third of injectors who enter prison inject when in prison, and of these about three-quarters share needles and syringes. In the present study, 44 drug injectors who had been released from prison for no longer than 6 months were recruited and interviewed in three geographical areas in England. Interviewees were asked to recount their experiences of drug use during their most recent period of imprisonment. The majority of interviewees were male (38/44), had a mean age of 28 years, with a mean age of 16 years at first drug use, were primarily opiate users (39) and had multiple imprisonments. All respondents reported drug use when imprisoned and drug injecting was reported by 16 interviewees. Most injected at irregular intervals and at a reduced level, compared with injecting when in the community. Nine reported using needles and syringes that others had previously used. When considering other injecting equipment, more sharing occurred than was actually reported. Much re-use of equipment was viewed simply as "using old works". The sharing of "cookers" and "filters", and drug sharing by "backloading" and "frontloading" were common. The concept of "sharing" tended to be understood by respondents as related to the use of tools of injection (needles and syringes rather than other equipment); the use of tools in the act of injection (rather than for mixing drugs); proximity (multiple use of needles and syringes in the presence of others); temporality (shorter time elapse between consecutive use of needles and syringes previously used by another) and source (hired rather than borrowed or bought). We conclude that syringe sharing is an integral part of drug use and drug injecting in prison. Many of those interviewed displayed a restricted understanding of what denotes syringe sharing. Our data reinforce the need for interventions and initiatives to be developed within prisons to deal with the considerable risk posed by continued injecting drug use.

Journal Article↗