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PubMed2006

Injection drug users' perceptions regarding use of a medically supervised safer injecting facility.

BACKGROUND: In recent years, there has been increased interest in supervised safer injecting facilities (SIF) as a strategy to reduce the harms of illicit drug use; however, little work has been done to assess drug users' satisfaction with this service. This study was undertaken to explore injection drug users' experiences and opinions regarding North America's first SIF in Vancouver, Canada. METHODS: Injection drug users (IDU) were randomly recruited from within the Vancouver SIF and invited to enroll in the Scientific Evaluation of Supervised Injecting (SEOSI) cohort. For the present study, participants were then surveyed regarding their experiences and beliefs regarding the SIF. RESULTS: Of 1082 IDU surveyed, 809 (75%) reported that their injecting behavior had changed as a result of using the SIF. Among these individuals, 80% indicated that the SIF had resulted in less rushed injecting, 71% indicated that the SIF had led to less outdoor injecting and 56% reported less unsafe syringe disposal. The three most common features always or usually limiting IDU's use of the SIF were: travel to the SIF (12%), limited operating hours (7%), and waiting times to access the SIF (5%). When asked in what ways the SIF might be improved, the three most common suggestions were: longer hours of operation (53%), addition of a washroom (51%), and reduced waiting times (46%). CONCLUSIONS: Many IDU reported changes in their injecting behaviors that have important implications for community and public health. Addressing a number of programmatic issues related to operating hours and waiting times, and the provision of additional amenities within SIF, may help to further improve their impact.

Adult↗

PubMed2004

A comparison of injection and non-injection methamphetamine-using HIV positive men who have sex with men.

There is a paucity of research on the psychosocial and behavioral characteristics of individuals who inject methamphetamine (meth). The present study compared injection and non-injection users of meth in terms of background characteristics, drug use patterns, health and social problems, sexual risk behavior, and psychosocial factors. The sample consisted of 194 HIV+Men who have Sex with Men (MSM) who were enrolled in a sexual risk reduction intervention for meth users. Men who injected meth were significantly more likely to be Caucasian, bisexual, homeless, divorced/separated, with lower educational attainment as compared to non-injectors. Injectors also reported more years of meth use, greater frequency and amount of meth use, more social and health problems, including higher prevalence of STDs and Hepatitis C, and more sexual risk behaviors. In terms of psychosocial factors, injection users of meth scored significantly higher on measures of impulsivity and experiences of rejection, and lower on a measure of emotional support. A multivariate logistic regression revealed that educational attainment and experiences of rejection were the factors that best discriminated between injection and non-injection users of meth. The unique characteristics of injection meth users are discussed in relation to the development of effective HIV prevention programs for the target population.

Adult↗

PubMed2003

Randomized controlled trial comparing epinephrine injection plus heat probe coagulation versus epinephrine injection plus argon plasma coagulation for bleeding peptic ulcers.

BACKGROUND: Epinephrine injection with heat probe coagulation is an effective treatment for bleeding peptic ulcer. Few studies have investigated the efficacy of dual therapy with epinephrine injection plus either heat probe or argon plasma coagulation for high-risk bleeding peptic ulcers. This study compared epinephrine injection plus heat probe coagulation to epinephrine injection plus argon plasma coagulation for the treatment of high-risk bleeding peptic ulcers. METHODS: The study design was prospective, randomized, and controlled. Patients with actively bleeding peptic ulcers, ulcers with adherent clots, or ulcers with nonbleeding visible vessels were randomly assigned to epinephrine injection plus heat probe coagulation or epinephrine injection plus argon plasma coagulation. Patients with previous gastric surgery, malignant ulcers, and unidentifiable ulcers because of torrential bleeding were excluded. The primary outcome measure was recurrence of bleeding. Secondary outcome measures were initial hemostasis, endoscopic procedure duration, number of patients requiring surgery, mortality within 30 days, and ulcer status at 8 week follow-up endoscopy. RESULTS: One hundred ninety-two patients were enrolled; 7 with malignant ulcers were excluded after randomization. One hundred eighty-five cases were analyzed, 97 in the heat probe group and 88 in the argon plasma coagulation group. Patient demographics and ulcer characteristics were comparable between the groups. There was no significant difference in terms of initial hemostasis (95.9% vs. 97.7%), frequency of recurrent bleeding (21.6% vs. 17.0%), requirement for emergency surgery (9.3% vs. 4.5%), mean number of units of blood transfused (2.4 vs. 1.7 units), mean hospital stay (8.2 vs. 7.0 days), and hospital mortality (6.2% vs. 5.7%). Sixty (61.8%) patients in the heat probe group and 52 (52.9%) in the argon plasma coagulation group underwent endoscopy at 8 weeks. There was no significant difference between these groups in the relative frequency of nonhealing ulcer at 8 weeks. CONCLUSION: Epinephrine injection plus argon plasma coagulation is as safe and effective as epinephrine injection plus heat probe coagulation in the treatment of patients with high-risk bleeding peptic ulcers.

Adult↗

PubMed2003

Tracking of injected and resident (previously injected) bacterial cells in groundwater using ferrographic capture.

A high-resolution bacterial tracking technique, ferrographic capture, was used to enumerate fluorescent-stained bacterial cells that were injected into groundwater during a field experiment. The goal of the experiment was to investigate whether detachment of previously injected stained resident cells attached to aquifer sediment was enhanced in the presence of the newly injected mobile cells. This injection was an improvement on past experiments in that the attached (resident) cells were stained, allowing their concentrations to be enumerated directly by ferrographic capture (upon detachment). Contrary to expectations based on previous experiments, enhanced detachment of stained resident cells did not occur upon the arrival of injected cells. Consistent with previous experiments, however, was the observation of ephemeral increases in unstained cell concentrations coincident with the arrival of the stained injected cells. The ephemeral pulses of unstained cells were previously speculated to represent enhanced detachment of unstained indigenous cells in response to hydrodynamic collision with injected cells. The lack of enhanced detachment of stained resident cells in the present experiments indicates that increased concentrations of unstained cells may have occurred by mechanisms other than hydrodynamic collision. Visually observed variations in stain intensity indicated that increased unstained cell concentrations may have resulted from cell division at the low-concentration fringe of the injected plume.

Aerobiosis↗

PubMed2005

Injecting shared drugs: an observational study of the process of drug acquisition, preparation, and injection by Puerto Rican drug users.

The practice of injecting shared drugs, in which drug users prepare, divide and inject portions of a drug solution, is a means of transmitting HIV, HCV, and other blood-borne pathogens. This study examined the process of injecting shared drugs among drug users in San Juan, Puerto Rico, through detailed observations of 25 episodes of the injection of shared drugs, and by informal interviewing of episode participants. The ways in which price and packaging of drugs, access to drug preparation materials, and social and economic relations between drug-sharing "partners" influence the process of injecting shared drugs are explored. Because differential power relations, and in turn, injection drug users' exposure to HIV and HCV, are apparent in some drug-sharing partnerships, a key objective of this study was to extend our understanding of contributions or "investments" made by different drug-sharing partners, the benefits and costs that different partners experience, and the extent to which IDUs assume different partner roles. The findings of this small, in-depth qualitative study provide insight into drug users' motivations for injecting shared drugs, and suggest reasons why certain standardized, countrywide HIV/HCV intervention efforts have not been entirely successful in preventing the devastating illnesses that disproportionately affect injection drug users.

Adult↗

PubMed2007

Convergence of HIV seroprevalence among injecting and non-injecting drug users in New York City.

OBJECTIVE: To compare HIV prevalence among injecting and non-injecting heroin and cocaine users in New York City. As HIV is efficiently transmitted through the sharing of drug-injecting equipment, HIV infection has historically been higher among injecting drug users. DESIGN: Two separate cross-sectional surveys, both with HIV counseling and testing and drug use and HIV risk behavior questionnaires. METHODS: Injecting and non-injecting heroin and cocaine users recruited at detoxification and methadone maintenance treatment from 2001-2004 (n = 2121) and recruited through respondent-driven sampling from a research storefront in 2004 (n = 448). RESULTS: In both studies, HIV prevalence was nearly identical among current injectors (injected in the last 6 months) and heroin and cocaine users who had never injected: 13% [95% confidence interval (CI), 12-15%] among current injectors and 12% (95% CI, 9-16%) among never-injectors in the drug treatment program study, and 15% (95% CI, 11-19%) among current injectors and 17% (95% CI, 12-21%) among never injectors in the respondent driven sampling storefront study. The 95% CIs overlapped in all gender and race/ethnicity subgroup comparisons of HIV prevalence in both studies. CONCLUSIONS: The very large HIV epidemic among drug users in New York City appears to be entering a new phase, in which sexual transmission is of increasing importance. Additional prevention programs are needed to address this transition.

Adult↗

PubMed2001

Large decline in injecting drug use in Amsterdam, 1986-1998: explanatory mechanisms and determinants of injecting transitions.

OBJECTIVES: To study community wide trends in injecting prevalence and trends in injecting transitions, and determinants. DESIGN: Open cohort study with follow up every four months (Amsterdam Cohort Study). Generalised estimating equations were used for statistical analysis. SETTING: Amsterdam has adopted a harm reduction approach as drug policy. PARTICIPANTS: 996 drug users who were recruited from 1986 to 1998, mainly at methadone programmes, who paid 13620 cohort visits. MAIN RESULTS: The prevalence of injecting decreased exponentially (66% to 36% in four to six monthly periods). Selective mortality and migration could maximally explain 33% of this decline. Instead, injecting initiation linearly decreased (4.1% to 0.7% per visit), cessation exponentially increased (10.0% to 17.1%), and relapse linearly decreased (21.3% to 11.8%). Non-injecting cocaine use (mainly pre-cooked, comparable to crack) and heroin use strongly increased. Trends were not attributable to changes in the study sample. CONCLUSIONS: Harm reduction, including large scale needle exchange programmes, does not lead to an increase in injecting drug use. The injecting decline seems mainly attributable to ecological factors (for example, drug culture and market). Prevention of injecting is possible and peer-based interventions may be effective. The consequences of the recent upsurge in crack use requires further study.

Adult↗

PubMed2006

Comparing injecting and non-injecting illicit opioid users in a multisite Canadian sample (OPICAN Cohort).

Illicit opioid use in Canada and elsewhere increasingly involves a variety of opioids and non-injection routes of administration. Injection and non-injection opioid users tend to differ in various key characteristics. From a public health perspective, non-injection routes of opioid use tend to be less harmful due to lesser morbidity and mortality risks. Our study compared current injectors (80%) and non-injectors (20%) in a multi-site sample of regular illicit opioid users from across Canada ('OPICAN' study). In bivariate analysis, injectors and non-injectors differed by prevalence in social and health characteristics as well as drug use. Logistic regression analysis identified city, drug use, housing status and mental health problems as independent predictors of injection status. Further analysis revealed that the majority of current non-injectors had an injection history. Our results reinforce the need to explore potential interventions aimed at preventing the transition from non-injectors to injecting, or facilitating the transition of injectors to non-injecting, as initiated in several other contexts.

Adult↗

PubMedDate not supplied

My place, your place, or a safer place: the intention among Montréal injecting drug users to use supervised injecting facilities.

BACKGROUND: Supervised injection facilities (SIF), a harm reduction intervention, may reduce several risks of public injection drug use. The prospect of conducting a scientific, multi-site pilot project of these facilities is being explored at federal and local levels in Canada. Experiences with SIF in Europe and Australia indicate that successful outcomes for the community ultimately hinge upon the responsiveness and relevance of the facilities to the needs of their primary target group: people who inject drugs in public places. Consideration of the factors and conditions found to influence a potential user's uptake of SIF, therefore, is imperative. This study sought to assess the acceptability of SIF and to determine factors associated with willingness of injecting drug users (IDU) to use SIF in a city considering their establishment. METHODS: From April 2001 to February 2002, following key informant interviews, a cross-sectional study was conducted among publicly injecting IDU participating in an ongoing HIV surveillance study in Montréal. Univariate and bivariate analyses preceded logistic regression. RESULTS: Participants were 11 key informants and 251 publicly injecting IDU. Key informants generated the Montréal-specific SIF model subsequently presented to IDU. 76% of IDU were willing to use at least one of three proposed SIF sites. Exploratory multivariable models indicated drug-use characteristics and SIF attributes as determinants of outcome: predominant cocaine injection, history of overdose, knowing about SIF, relieving and empowering feelings toward using SIF, and comfort with disclosure of one's injecting drug use. CONCLUSION: User consultations are essential to assess relevance and plan SIF acceptable to IDU.

Chi-Square Distribution↗

PubMed1995

Changes in the injecting risk behaviour of injecting drug users in London, 1990-1993.

OBJECTIVE: To describe changes in the injecting risk behaviour of injecting drug users (IDU) in London between 1990 and 1993. DESIGN: Injecting risk behaviour was measured over 4 years (1990-1993) in a serial point HIV prevalence study of 2062 IDU recruited in both drug treatment and non-treatment community-based settings within greater London. The study used a structured questionnaire and common sampling and interview strategy developed by a World Health Organization technical group and implemented in 13 cities. METHODS: Log-linear models were used to assess patterns of change over years and of differences in injecting risk behaviour, including syringe sharing and syringe hygiene between 1990 and 1993. The log likelihood chi 2 statistic, G2, was used to test statistical significance. Changes in the mean values were assessed first using parametric tests assuming normality and the results were compared with Kruskal-Wallis (non-parametric) tests. Pearsons chi 2 was used to measure differences in frequency of sharing occasions and partner selectivity. RESULTS: An overall reduction in injecting risk behaviour was observed during the first 2 years of this study, including a decline in syringe sharing (both accepting and passing on used syringes), the number of sharing partners and the frequency of sharing occasions. Most sharers restricted sharing to sexual partners and close friends. The majority of sharers reported always cleaning injecting equipment. Main source of sterile equipment was pharmacies and syringe exchanges. Indirect sharing (of spoons, filters, and by front- or backloading) was reported. Since 1991 there has been a stabilization in risk behaviour. CONCLUSIONS: The data indicate that IDU in London have made positive reductions in risk behaviour. Levels of syringe sharing were substantially lower than those reported up to 1987 before AIDS awareness and the introduction of HIV prevention measures. The majority did not share syringes or confined their sharing to close friends and sexual partners, and if shared, cleaned their syringes. Continuation of indirect sharing indicates the need for more detailed prevention messages. While the initial decline in syringe-sharing rates may be attributed to the wide availability of sterile injecting equipment and other preventive measures, it may now be necessary to look beyond current intervention initiatives to develop interventions which seek to change the social etiquette of sharing and move towards the long-term maintenance of low levels of injecting risk behaviour.

Adult↗

PubMed1998

Injecting behaviours and prevalence of hepatitis B, C and D markers in New Zealand injecting drug user populations.

AIM: To determine the seroprevalence of hepatitis C virus (HCV), hepatitis B virus (HBV) & hepatitis D virus (HDV) markers of infection among injecting drug user populations in New Zealand and to examine the relationship between demographic features, risk behaviours and infection. METHODS: A total of 323 current injecting drug users completed a questionnaire that explored their needle and syringe using behaviours. Information was collected on injection pattern, sharing behaviours and methods of cleaning needles and syringes. Two hundred and forty-one respondents gave blood samples which were tested for hepatitis B, C and D markers. RESULTS: Over half the respondents (59%) were male and 41% were female. Most (89%) identified as European. Sixty-four percent were anti-HCV positive. The likelihood of infection increased with age and duration of injecting. Forty-one percent (33/81) of those aged 25 or under, sixty-four percent (45/70) of those aged 26-30 and eighty-seven percent (78/90) over 30 were anti-HCV positive. Those who tested anti-HCV positive had been injecting for an average of 12.0 years compared to 6.0 years for those were anti-HCV negative. The results for hepatitis B are to be reported fully at a later date. Sharing behaviour was also a factor although this was less important as an independent factor. Comparisons with earlier surveys suggested that there has not been a significant decline in the rate of sharing needles and syringes since the initial period following introduction of the needle exchange programme. CONCLUSION: The prevalence of hepatitis C infection is common among injecting drug users of all ages. Without a significant reduction in sharing behaviour, particularly among younger injecting drug users, it is unlikely that the prevalence of hepatitis C among injecting drug users will decline in the future. Evidence suggests that the carriage of hepatitis C is higher than that of hepatitis B which would help explain the differing rates of prevalence. However, the risk of future transmission of other parenterally transmitted diseases remains high without a further significant decline in sharing behaviour.

Adolescent↗

PubMed1995

A multicentred phase III comparative clinical trial of Mesigyna, Cyclofem and Injectable No. 1 given by intramuscular injection to Chinese women. II. The comparison of bleeding patterns.

Between 1988 and 1992, a randomized phase III clinical trial was conducted in China to compare three monthly injectable contraceptives: Mesigyna, Cyclofem and Injectable No. 1. This paper presents a detailed analysis of the menstrual diaries provided by 5098 (89%) of the subjects. In total, 902, 903 and 913 diaries were analyzed to compare bleeding patterns induced by Mesigyna, Cyclofem and Injectable No. 1. The first withdrawal bleeding usually occurs 14-20 days after the first injection for all three of these preparations. Thereafter, 50% of Mesigyna users had precisely 3 bleeding/spotting episodes every 90 days, 50% of Cyclofem users had 2-3 and 50% of Injectable No. 1 users had 3-4 episodes every 90 days. Relative to users of Mesigyna or Cyclofem, Injectable No. 1 users had 2-3 more bleeding/spotting days, and a shorter length of bleeding/spotting-free intervals in each period. 63.7%, 41.4% and 60.6% of subjects using Mesigyna, Cyclofem and Injectable No. 1, respectively, had bleeding patterns similar to their untreated patterns in the first 90-day period. The percentages increased to 82.2% 67.8% and 75.0% in the fourth 90-day period. A total of 1815 diaries for Mesigyna and 1802 for Cyclofem were analyzed for more in depth comparison of these two methods. The number of bleeding/spotting days over four periods showed little difference between the two group, but there were more spotting days and there was greater individual variability among Cyclofem users.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Influence of concentration and injection volume on the bioavailability of subcutaneous growth hormone: comparison of administration by ordinary syringe and by injection pen.

In order to study whether the bioavailability of subcutaneously injected growth hormone (GH) is dependent on the concentration/volume injected, the relative GH bioavailability was evaluated in 14 GH-deficient patients. In a cross-over study the patients received, in random order two separate subcutaneous GH injections (Norditropin) 4 IU administered by means of an ordinary syringe (4 IU ml) and an injection pen with cartridge (Nordiject 24) (12 IU/ml). Blood samples were drawn over a 14 hr period and assayed for serum concentrations of GH and IGF-I. The mean value (+/- S.D.) of the relative absorption fraction (Fpen/sy) was 1.09 +/- 0.39. Mean values of Cmax were 8.6 ng/ml +/- 4.8 and 8.3 ng/ml +/- 7.5 for syringe and pen respectively. Corresponding values for Tmax were 311 min. +/- 131 for syringe and 309 min. +/- 104 for pen. Although a considerable interindividual variation was seen, the relative absorption fraction did not differ significantly from 1 (2 P = 0.78). Further there was no significant difference in neither Cmax (2 P = 0.39) nor Tmax (2 P = 0.55). IGF-I serum profiles tended to be higher following syringe compared to pen injection (2 P = 0.054). On the basis of this study we conclude that in this dosage regimen. GH bioavailability following pen injection equals that of injection by syringe (i.e. no effect of a three fold increase/decrease in GH concentration/volume respectively).

Adult↗

PubMed2003

[Methotrexate administration in the treatment of unruptured tubal pregnancy. Prospective non-randomized study: intramuscular injection versus transvaginal sonography-guided injection].

OBJECTIVES: The aim of this study was to compare in a prospective non-randomized study, the efficacy of two methods of administering methotrexate (MTX) in the treatment of ectopic pregnancy (EP): transvaginal injection under sonographic control or intramuscular injection (IM). METHODS: Patients with EP who met specific inclusion criteria for medical treatment were treated by MTX: 73 patients (group 1) were treated by IM and 47 patients (group 2) by transvaginal local injection. MATERIALS AND METHODS: In group 1,50 mg/m(2) of MTX was injected intramuscularly; in group 2,1 mg/kg of MTX was injected transvaginally into the ectopic sac under sonographic guidance. Choice of the route depended on the physician's experience. RESULTS: The overall success rate, defined by a normal post-treatment hCG level (<10 mUI/mL) was 71.4% in group 1 versus 91.5% in group 2 (p<0.01); for patients with hCG levels<2,000 mUI/mL, 83% and 96% respectively (not significant); for patients with hCG 2,000 mUI/mL, 37.5% and 86.4% respectively (p<0.01). CONCLUSION: For medical treatment of EP, the efficacy of MTX is greater when administered by local transvaginal injection than by IM injection. We propose local treatment whenever the EP can be punctured, especially when hCG levels are 2,000 mUI/mL.

Abortifacient Agents, Nonsteroidal↗

PubMed2005

Areolar-cutaneous junction injection boosts activity in sentinel node by more than 50 times compared to perilesional injection: implications for morbidity reduction.

The combination of concurrently administered perilesional radiotracer injections and areolar-cutaneous junction radiotracer injections during one imaging session in the detection of sentinel nodes (SN) in breast cancer is new. A case is presented where the perilesional injections of radiotracer produced a faint node. Subsequently, 45 minutes later, the same patient received an injection of radiotracer at the areolar-cutaneous junction, which "boosted" the activity in the original SN by more than 50 times. This case illustrates the marked improvement in SN counts that can occur with the addition of areolar-cutaneous junction injections to perilesional injections. The perilesional component of this hybrid injection technique maintains the ability to visualize internal mammary and extra-axillary SN. Even more importantly, these "hotter" nodes have significant implications for morbidity reduction, the main goal of sentinel lymph node biopsy in itself.

Adult↗

PubMed2003

Subareolar subcutaneous injection of blue dye versus peritumoral injection of technetium-labeled human albumin to identify sentinel lymph nodes in breast cancer patients.

Lymphatic mapping in breast cancer patients is a widely used technique for axillary staging, though the optimal technique is not yet established. The purpose of this study was to show that subareolar and subcutaneous injection of blue dye drains to the same sentinel lymph node (SLN) in the axillary basin as does peritumoral injection of technetium (Tc)-labeled albumin. Two injection methods were compared in 154 consecutive patients with newly diagnosed pT1 or pT2 breast cancers (tumor size 5-45 mm). The diagnosis of invasive breast cancer was confirmed by core needle biopsy. Peritumoral injection of 40 to 60 MBq 99Tc-labeled colloidal albumin was performed 18 to 20 hours prior to surgery. In addition, 2 ml of blue dye was injected subcutaneously into the subareolar plexus of the same patients exactly 5 minutes prior to incision and dissection of the SLNs. The blue and hot SLNs were identified by searching for the blue lymphatic vessel and the blue lymph node and by counting the radioactivity with a gamma probe. The correlation between the blue nodes and the hot nodes was examined. Altogether, 154 patients were enrolled in the study. Three patients had bilateral breast cancer, and a total of 157 sentinel lymph node biopsies (SLNBs) were performed. The SLNs could be identified in 155 of the 157 SLNBs (98.7%), and the hot node clearly corresponded to the blue node in 151 of the 155 SLNBs (97.4%). Neither a hot node nor a blue node could be identified in 2 of the 157 SLNBs (1.3%). No concordance between the blue node and the hot node could be achieved in 4 of the 155 SLNBs (2.6%). Injection of blue dye into the subareolar lymphatic plexus shows excellent correlation with peritumoral injection of technetium-labeled albumin concerning the identification of SLNs. Our results support the hypothesis that the lymphatic drainage of the breast parenchyma and the subareolar plexus leads to the same sentinel lymph node. It is a rapid, reliable method for identifying SLNs in breast cancer patients. It is easy to perform, especially in nonpalpable tumors, and it does not disturb surgery by discoloring peritumoral tissue.

Adult↗

PubMed2003

Effect of contrast injection protocol with dose tailored to patient weight and fixed injection duration on aortic and hepatic enhancement at multidetector-row helical CT.

The aim of this study was to investigate the effect of a contrast material injection protocol with dose and injection rate of contrast material tailored to patient weight (dose tailored to patient weight and fixed injection duration). Hepatic helical CT was performed in 92 patients with chronic liver damage with a dose of 1.4 ml (518 mgI) at a rate of 0.056 ml/s per kilogram body weight of Iopamidol 370. Attenuation values of liver and aorta were measured for calculation of maximum aortic and hepatic enhancement, time to maximum hepatic enhancement, and end of hepatic arterial phase. Correlation coefficients between the injection rate and the four parameters were r=0.008, 0.057, 0.167, and 0.036, and there were no statistically significant correlations between the injection rates and the four parameters. In our injection protocol, uniform temporal scan window may be achieved and the injection rate can be reduced in lighter patients without reducing the degree of enhancement in the aorta and the liver.

Aged↗

PubMedDate not supplied

Prolongation of cardiac allograft survival by intraportal injection of donor antigens--differential mechanisms according to the timing of injection.

Recently, we reported that intraportal (IP) injection of donor spleen cells (SPCs) before transplantation as well as at the time of transplantation significantly prolongs cardiac allograft survival in rats (7). Long-term establishment of chimerism induced by intraportal administration of SPCs could be a part of this prolongation. In this study, we examined the effect of irradiation of SPCs as a source of donor antigens on cardiac allograft survival. Experiments were carried out using DA (RT1a) as the donor and BUF (RT1b) as the recipient strain. Fifty million irradiated or nonirradiated SPCs were injected either intravenously (i.v.) or intraportally (i.p.) on day -10 or day 0, the day of cardiac allografting. Untreated animals rejected allografts within a mean survival time (MST) of 7.2 +/- 0.8 days (n = 5). Injection (i.p.) of SPCs on both day -10 (n = 4) and day 0 (n = 6) induced significant prolongation of MST over the control (19.0 +/- 4.7, 14.2 +/- 2.1 days; p < 0.001 vs. control), while i.v. injection of SPCs on either day -10 (n = 4) or day 0 (n = 4) failed to do so (9.2 +/- 1.0, 8.5 +/- 0.6 days). Significant prolongation was still observed when irradiated SPCs were injected on day -10 (n = 4; MST: 19.0 +/- 5.4 days, p < 0.002 vs. control), but not when injected on day 0 (n = 5; MST: 9.4 +/- 2.1 days). These data suggest that the immunosuppressive effect of i.p. injection of donor SPCs could be induced by differential mechanisms according to the timing of inoculation of donor antigens.

Animals↗