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PubMed2004

Hemifacial spasm: results of treatment with low dose botulinum toxin injection.

BACKGROUND: Hemifacial Sapsm (HFS) is a common movement disorder in Thailand. Botulinum toxin type A (BTA) is an effective and safe treatment for this condition. The success of BTA treatment depends on the experience of the clinician. OBJECTIVE: To study the demographic data, efficacy and safety of low dose BTA injection in HFS patients. SETTING: The Spastic and Dystonia Clinic, Department of Rehabilitation Medicine, King Chulalongkorn Memorial Hospital. DESIGN: Open-label, prospective case-series study. PATIENTS: All patients with HFS referred for BTA injection from December 1st, 1995 to November 30th, 2003. METHOD: Sex, age, side of spasm, onset of symptoms before BTA injection, underlying diseases, sites of BTA injection, dose of each BTA treatment, duration of response, efficacy, and side-effects were analyzed. 3-5 units of BOTOX were intramuscularly injected per site to all muscles that had spasm. After injection, a 20-minute cold compression on the first day was followed by 20-minute warm compression with massage at each injection site per day for 14 days. RESULTS: A total of 112 patients with HFS were treated with 874 BTA treatments. There were 71 females (63.4%) and 41 males (36.6%). The mean age was 45 years. 75 patients (67%) were affected on the left side. Mean duration of symptoms was 3.4 years. The sites of injection were orbicularis occuli and orbicularis oris muscles in all 874 treatments (100%). The mean dose of all treatments was 25 units. The mean initial dose was 30.5 units. The mean dose for subsequent injection was 23 units. The mean duration between treatments was 4.7 months. The mean initial duration was 3.5 months. The mean duration for subsequent injection was 4.8 months. The outcomes of treatment assessed at 4 weeks after injection classified as excellent (>80% improvement) were found in 845 treatments (96.7%). Most treatments had no complication (91.9%). Ptosis, facial paresis and double vision were mild and transient, lasting 1-4 weeks. There were no long-term complications of BTA treatment in the present series. CONCLUSION: Low dose BTA injection is an effective treatment for hemifacial spasm patients. There was a longer duration of response in subsequent injections and a lower complication rate in the present study when compared to others.

Adult↗
PubMed1993

Stability of fluconazole in injectable solutions.

The stability of fluconazole 1 mg/mL in several injectable solutions at 25 degrees C over 72 hours was studied. Fluconazole 2 mg/mL was mixed in a 1:1 ratio with 5% dextrose injection, lactated Ringer's injection, potassium chloride 20 meq/L in 5% dextrose injection, heparin sodium 100 units/mL in 5% dextrose injection, theophylline 0.8 mg/mL in 5% dextrose injection, and morphine sulfate 0.5 mg/mL in 5% dextrose injection. Three 1-mL samples were taken from each admixture at 0, 6, 12, 24, 36, 48, and 72 hours and analyzed for fluconazole concentration by stability-indicating gas chromatography. Fluconazole 2 mg/mL was stable in potassium chloride plus 5% dextrose injection and in theophylline plus 5% dextrose injection for 72 hours. Fluconazole was stable in the other injectable solutions for 24 hours. The stability of theophylline, heparin, or morphine sulfate in the presence of fluconazole was not studied. Fluconazole was stable in potassium chloride 20 meq/L plus 5% dextrose injection and in theophylline 0.8 mg/mL plus 5% dextrose injection for 72 hours and stable in the other injectable solutions for 24 hours.

Drug Interactions↗
PubMed1998

Comparison of long-term outcomes of penile prostheses and intracavernosal injection therapy.

PURPOSE: Intracavernosal injection therapy is one of the most popular therapies for erectile dysfunction today. Yet, most clinicians consider intracavernosal injection a palliative treatment for erectile dysfunction because of the high patient initiated dropout rate. In contrast, penile prostheses appear to offer a more permanent cure for erectile dysfunction. We compare the long-term outcomes of both therapies in contemporaneously treated patients and determine the reasons for failure of each. MATERIALS AND METHODS: Telephone survey and chart review was conducted on the first 115 patients treated with intracavernosal injection and 65 patients undergoing insertion of a penile prosthesis during the same period at our institution. Mean patient age was 57 and 60 years, respectively, and mean followup of all patients was 5.4 years (range of 3.3 to 16). RESULTS: An equal percentage of patients were lost to followup in both groups, including 19% of the intracavernosal injection group and 18% of the penile prosthesis group. Of the intracavernosal injection patients 6 (6%) died during followup and 10 (19%) of the prosthetic patients died (p < 0.05). At the time of contact only 41% of the patients were still using intracavernosal injection. In contrast, 70% of the patients were still sexually active with the prosthesis (p < 0.01). Mean duration of use of the penile prosthetics was 63 months compared to 37 months for intracavernosal injection (p < 0.001). The most common reasons for discontinuing intracavernosal injection were inadequate erections (16 cases), lack of spontaneity (14), side effects (12), lack of partner (10), loss of sexual interest (6) and spontaneous return of normal erections (4). More than half of the patients (61%) who discontinued intracavernosal injection remain sexually active with other therapies, including penile prosthesis in 11, vacuum devices in 4, vascular surgery in 1 and oral medication in 1, and 14 without any therapy. We could not identify any significant clinical parameters that would accurately predict which patients most benefited by the long-term use of intracavernosal injection therapy. In contrast, only 6 patients discontinued use of the implant because of complications (infection, erosion and malfunction) and 7 for reasons independent of the implant (that is lack of partner, loss of sexual interest and co-morbidity). CONCLUSIONS: Intracavernosal injection serves as only a palliative therapy for the majority of patients with erectile dysfunction but there exists a core group who derives long-term satisfaction with its use. The majority of patients who discontinue intracavernosal injection remain sexually active yet do not progress to more invasive or effective therapies. The reason for discontinuing therapies for erectile dysfunction is often unrelated to the actual therapeutic modality. Our findings suggest that further improvements in intracavernosal injection therapy and the development of alternative methods of delivery of vasoactive agents will have only a limited impact on the overall outcome of therapy for erectile dysfunction and that increased attention to issues separate from the erection is warranted.

Adult↗
PubMedDate not supplied

A survey: conscious sedation with epidural and zygapophyseal injections: is it necessary?

BACKGROUND CONTEXT: Substantial variation exists regarding the use of sedation before interventional spine techniques. Patient preference should play an important role in decision making regarding the need for sedation. However, little is known about patients' anxiety levels before spinal injections and their perceptions about the necessity of sedation. PURPOSE: To determine patient perception for need for sedation before epidural steroid injections and zygapophyseal joint injections. STUDY DESIGN/SETTING: Survey of consecutive spinal injection patients in an outpatient spine center. PATIENT SAMPLE: 500 consecutive lumbar, thoracic, and cervical patients receiving spinal injections. OUTCOME MEASURES: A 12-item questionnaire assessing patients' perceived anxiety before to a spinal injection. METHODS: Subjects were given the questionnaire after their spinal injection. Percentages requesting sedation for a first and potential second procedure were assessed. Additionally, anxiety level and pain rating, location of injection, age, sex, and other medication use were analyzed to determine the effect on the request for sedation. RESULTS: 17% of patients questioned requested sedation before an injection, and 28% would request sedation if they were to have a second injection. CONCLUSIONS: Routine sedation before diagnostic and therapeutic injections is not necessary as the majority of patients would not request sedation before the procedure when given the option. However, in some patients sedation is indicated, and all patients would benefit from educational material on sedation before the injection.

Anxiety↗
PubMed1965

THE MECHANISM OF TOLERANCE PRODUCED IN RATS TO SHEEP ERYTHROCYTES. I. PLAQUE-FORMING CELL AND ANTIBODY RESPONSE TO SINGLE AND MULTIPLE INJECTIONS OF ANTIGEN.

Previous studies suggested that an active immune response was partially responsible for maintaining immunological unresponsiveness to sheep erythrocytes. Measurement of the plaque-forming (antibody-releasing) cell response proved to be a sensitive indicator of an immune response to sheep erythrocytes in the absence of detectable circulating antibody to the antigen. The present studies were undertaken to determine whether an active immune process, measured by the plaque-forming cell response, was partially responsible for induction and maintenance of tolerance. Rats injected intraperitoneally with large doses of sheep erythrocytes beginning at the day of birth develop tolerance to the antigen. In this paper, the plaque-forming cell and antibody response to sheep erythrocytes was characterized for rats receiving a single antigen injection at various ages and for rats which received repeated antigen injections as adults. The dose of antigen was the same as that used to produce tolerance; the injection schedule for repeated immunizations was also the same as that used to produce tolerance. Rats receiving a single antigen injection on the day of birth or at age 7 days had no measurable response to the antigen. Rats receiving a single antigen injection at age 17 days and sacrificed 4 days later had an unequivocal response to the antigen. The spleens had about one-tenth as many plaque-forming cells as spleens of adult animals immunized similarly, but the antibody titers were as high as titers for adult animals. Presumably the high titers of these young animals resulted from the high ratio of plaque-forming cells to body weight and blood volume. Adult animals receiving a single antigen injection had a peak or near peak plaque-forming cell response 4 days after immunization; at this time, sera contained high titers of 19S antibody and the numbers of plaque-forming cells in spleens correlated reasonably well with circulating antibody titers. 7S antibody appeared in serum 5 or 6 days after immunization. The numbers of plaque-forming cells declined progressively 2 and 3 weeks after immunization. Repeated twice weekly, injections of the antigen in adult rats produced a marked decline and then stabilization of numbers of plaque-forming cells in spleens. Although the numbers of plaque-forming cells were fewer, titers of 19S and 7S antibody stabilized at high levels. A progressive recovery of the plaque-forming cell response and a rise in antibody titer occurred when the interval between the last 2 injections was increased from 3 to 10, 17, or 32 days. These findings suggested that repeated closely spaced antigen injections interfered with either cell division or maturation of antibody-forming cells. As the interval between injections was increased, additional antibody-forming cells matured or were formed through cell division. Thus, relatively constant antigenic stimulation provided a mechanism for controlling or limiting the response of antibody-forming cells. In the following paper, it will be shown that this mechanism operating together with a homeostatic mechanism which prevents induction of new antibody-forming cells serves to regulate the immune response to repeated injections of antigen.

Animals↗
PubMed2001

Injection therapy for subacute and chronic benign low back pain.

STUDY DESIGN: The Medline and Embase databases containing randomized controlled trials of injection therapy published to 1998 were systematically reviewed. OBJECTIVES: To evaluate the effectiveness of injection therapy with anesthetics, steroids, or both in patients with low back pain persisting longer than 1 month. METHODS: Two reviewers independently assessed the trials for the quality of their methods. The primary outcome measure was pain relief. Subgroup analyses were performed between trials with different control groups (placebo and active injections), with different injection sites (facet-joint, epidural, and local injections), and with timing of outcome measurement (short- and long-term). Within the resulting 12 (2 x 3 x 2) subcategories of studies, the overall relative risks and corresponding 95% confidence intervals were estimated, using the random effects model of DerSimonian and Laird. In the case of trials using active injections as a control, the results were not pooled. RESULTS: This review included 21 randomized trials. All the studies involved patients with low back pain persisting longer than 1 month. Only 11 studies compared injection therapy with placebo injections (explanatory trials). The methodologic quality of many studies was low: Only eight studies had a methodologic score of 50 points or more. There were only three well-designed explanatory clinical trials: one on injections into the facet joints with a short-term relative risk of 0.89 (95% confidence interval = 0.65-1.21) and a long-term relative risk of 0.90 (95% confidence interval = 0.69-1.17), one on epidural injections with a short-term relative risk of of 0.94 (95% confidence interval = 0.76-1.15) and a long-term relative risk of 1.00 (95% confidence interval = 0.71-1.41), and one on local injections with a long-term relative risk of 0.79 (95% confidence interval = 0.65-0.96). Within the six subcategories of explanatory studies, the pooled relative risks were as follows: facet joint, short-term: relative risk = 0.89 (95% confidence interval = 0.65-1.21); facet joint, long-term: relative risk = 0.90 (95% confidence interval = 0.69-1.17); epidural, short-term: relative risk = 0.93 (95% confidence interval = 0.79-1.09); epidural, long-term: relative risk = 0.92 (95% confidence interval = 0.76-1.11); local, short-term: relative risk = 0.80 (95% confidence interval = 0.40-1.59); and local, long-term: relative risk = 0.79 (95% confidence interval = 0.65-0.96). CONCLUSIONS: Convincing evidence is lacking regarding the effects of injection therapy on low back pain. Additional well-designed explanatory trials in this field are needed.

Anesthetics, Local↗
PubMed1991

Intraperitoneal injections of prostaglandin E2 attenuate hyperthermia induced by restraint or interleukin-1 in rats.

1. The purpose of this study was to investigate the effect of the intraperitoneal (I.P.), intravenous (I.V.) or intrapreoptic area (POA) injection of prostaglandin E2 (PGE2) on the body temperature of restrained and unrestrained rats. The effect of I.P. PGE2 on the body temperature of rats during fever induced by I.P. injection of interleukin-1 beta (IL-1 beta) was also investigated. 2. Prior to injection, restrained rats had body temperatures of approximately 1 degree C higher than unrestrained rats. The I.P. injection of PGE2 (0.05 and 0.5 mg kg-1) caused body temperature to fall towards the pre-restraint levels in a dose-dependent manner. This fall in body temperature was preceded by a sharp increase in tail skin temperature that was also dependent on dose. The I.P. injection of PGE2 had no effect on the body temperature of unrestrained animals. 3. The I.V. injection of PGE2 caused very little change in the body temperature of restrained rats. However, when injected I.V. into unrestrained animals, PGE2 caused dose-dependent fevers. The injection of PGE2 (50 ng) into the POA resulted in fever in both restrained and unrestrained animals. 4. The I.P. injection of IL-1 beta (10 micrograms kg-1) caused a biphasic fever that lasted at least 420 min. The I.P. injection of PGE2 180 min after the injection of IL-1 beta caused a transient decrease in the rats' body temperature. This drop in body temperature was not associated with a decrease in metabolic rate. 5. These data support the hypothesis that during restraint stress hyperthermia and IL-1 beta fever, the I.P. injection of PGE2 acts peripherally to lower the body temperature of rats.

Animals↗
PubMed1978

In situ injection of kainic acid: a new method for selectively lesioning neural cell bodies while sparing axons of passage.

The morphologic sequelae following stereotaxic injection into the rat striatum of kainic acid, a conformationally restricted analogue of glutamate, were examined by means of bright field, histofluorescence and electron microscopic techniques. The neuropathologic response to kainate injection occurs in two distinct phases. First, the intrinsic neurons of the striatum undergo a rapid degeneration during the first 48 hours after injection; this is characterized by the sequential loss of cytoplasmic Nissl-substance (chromatolysis), shrinkage of the perikarya, clumping of the nuclear chromatin and finally disruption of the nuclear membrane. Between one and three weeks after injection, a marked proliferation of astrocytes in the gray matter formerly populated by neurons characterizes the second phase. The region of several neuronal loss in the kainate injected striatum is approximately spherical in shape, and its extent is non-linearly related to the amount of kainate injected. The neuropil of the injected striatum is markedly disrupted due to the death of intrinsic neurons and loss of their processes. Yet, histofluorescence microscopy demonstrates that the dopaminergic axons projecting from the substantia nigra do not degenerate in the kainate injected striatum; electron microscope studies indicate that corticofugal fibers traversing the striatum are also unaffected by kainate. Many presynaptic boutons, presumably of extrinsic origin, are intact up to ten days after injection; osmophilic vestiges of postsynaptic elements remain adherent to these boutons. Numerous phagocytic astrocytes are observed throughout the lesioned area. These morphologic studies provide (direct) evidence that in situ injection of kainic acid in brain causes a selective degeneration of neurons with cell bodies in the area of the injection but spares axons that arise from perikarya outside the region but pass through or terminate in the injected area. Thus, in situ injection of kainic acid is a new technique for making selective brain lesions that will be useful for examining neuronal connectivity.

Animals↗
PubMed1988

Profiles of plasma androgens in quail following testosterone injection at two different times of day.

Adult castrated male Japanese quail (Coturnix japonica) housed on an 8L:16D light-dark cycle (lights on at 0700 hr) were given a single injection of either 100 or 500 micrograms testosterone (T) at either 0800 or 1430 hr. Blood samples were taken 1, 3, 5, 7, or 24 hr after injection and assayed for androgens. Additional samples were taken from intact males housed on a 16L:8D light-dark cycle and from castrated males housed on 8L:16D and injected with the oil vehicle. With the 100-micrograms dosage, T and total androgen fell to the level of the intact males by 3 hr after injection and fell to the level of oil-injected castrates by 5 to 7 hr. With the 500-micrograms dosage, T and total androgen, though initially quite high, reached intact levels by 3 hr when birds were injected at 0800 hr but not until 5 hr when injected at 1430 hr, and T reached castrate levels by 5 hr following injection at 0800 hr but not until 24 hr following injection at 1430 hr. T levels after a 500-micrograms injection at 0800 hr were significantly higher 3, 5, and 7 hr later than T levels after the same injection at 1430 hr. Thus changes in plasma T levels over time following an injection of T depend on the time of injection, and plasma T remains above castrate levels for a shorter time when T is given in the bird's morning than when given just before lights-off. This can probably be explained by a greater rate of metabolism during lights-on compared with lights-off.

Androgens↗
PubMed2006

Galanin treatment offsets the inhibition of bone formation and downregulates the increase in mouse calvarial expression of TNFalpha and GalR2 mRNA induced by chronic daily injections of an injurious vehicle.

We have previously shown that after bone fracture, galanin (GAL) and GAL receptor expression is increased in osteoblast-like cells of callus; however, the role of elevated GAL/GAL receptors in this instance of bone injury is not known. We hypothesize that in injury, GAL may facilitate bone formation by suppressing the production of cytokines such as TNFalpha and IL-1alpha, thereby affecting bone collagen formation and collagenolysis by key matrix metalloproteinases (MMPs). In studies to explore this hypothesis, we used a mouse calvarial injection model to (1) investigate whether mild injury caused by a daily subcutaneous injection of a glycerol-containing vehicle onto calvaria affected osteoblast/bone formation-associated histomorphometric parameters and gene expression (mRNA encoding GAL, GAL receptors, TNFalpha, IL-1beta, collagen type I, MMP-2 and -13) compared to non-injected, control mice and (2) determine the effect of GAL+vehicle treatment on these entities. Five groups of 4-week-old mice were used: a non-injected control group; a vehicle (50/50 solution of 10 mM PBS+0.025% BSA/5.4 M glycerol)-treated group; and 3 GAL-treated groups (0.2, 2 and 20 ng doses). Solutions were injected subcutaneously onto calvaria in a 10 mul volume, every day for 2 weeks. Vehicle injection reduced calvarial periosteal osteoblast cell height (P<0.001), osteoblast number (P<0.001) and osteoid thickness (P<0.01), relative to values in non-injected animals at 2 weeks. Vehicle injection also inhibited BFR in this periosteal bone relative to values in non-injected animals at both 1 and 2 weeks (P<0.05 and P<0.001, respectively). Increasing concentrations of GAL reversed the above-listed inhibitory effects caused by vehicle. This reversal was demonstrated by a dose-dependent effect of GAL on osteoblast cell height (Pearson's r=0.330; P<0.05), osteoblast number (Pearson's r=0.715; P=0.000), osteoid thickness (Pearson's r=0.516; P=0.000) and BFR (Pearson's r=0.525; P<0.05) after 2 weeks of GAL+vehicle treatment; with the 20 ng/day GAL+vehicle injection schedule returning these measured parameters toward non-injected control values. All GAL+vehicle treatments had no effect on calvarial expression of GAL, GALR1, GALR3, collagen type 1 and MMP-2 mRNAs compared to levels in vehicle-injected controls. GAL treatment did, however, produce dose-dependent effects on calvarial expression of GALR2 (Pearson's r=0.763; P=0.000), MMP-13 (Pearson's r=0.806; P=0.000), IL-1beta (Pearson's r=0.807; P=0.000) and TNFalpha (Pearson's r=0.542; P=0.000) mRNAs with 20 ng/day of GAL+vehicle producing the strongest reversal of vehicle-associated changes. Thus, the 20 ng/day GAL+vehicle regimen offset the inhibition of osteoblastic activity, and therefore bone formation caused by daily glycerol-containing vehicle injection. This effect on bone formation may be due in part to the peptide suppressing the formation and associated activity of TNFalpha, IL-1beta and MMP-13, as TNFalpha and IL-1beta are known inhibitors of bone formation and MMP-13 is involved in collagenolysis. Furthermore, these effects may be due to the action of GAL via GALR2, as it was the only GAL receptor affected by this GAL treatment regimen. These results indicate that GAL can facilitate bone formation associated with injury and reveal potential efficacy for GAL in treating osseous conditions where bone formation may be inhibited due to excess TNFalpha and IL-1beta production.

Animals↗
PubMed1981

Comparison of once daily and twice daily FSH injections for superovulating beef cattle.

Twelve cycling Angus-based crossbred cows were used in a crossover experimental design to evaluate two different injection schedules using Follicle Stimulating Hormone (FSH) for superovulating donor cattle. Females randomly assigned to Treatment (A) were given twice daily FSH injections of 5 mg each (12 hours apart) for five consecutive days starting on day 10 of the estrous cycle while those in Treatment (B) received the same daily dose level of FSH, except it was given in a 3.2% protein gelatin carrier vehicle and administered on a once daily injection schedule. Animals in both Treatments (A) and (B) were each given a 30 mg dose of commercially available prostaglandin-F(2alpha) agent 48 hours after the first FSH injection. Cows in estrus were initially handmated to a fertile bull then artificially inseminated 12 hours later with two units of frozen semen. All 12 animals (100%) given twice daily FSH injections and 11 of the females (91.6%) administered once daily FSH injections exhibited standing estrus within 5 days following injection of the luteolytic agent. On day 7 or 8 after the onset of standing estrus a laparotomy was performed to observe ovarian structures. When the superovulation response was evaluated, the mean number of corpora lutea per ovary ranged from 2.9 in the twice daily injection group to 4.1 in the once daily injected group. Unexpectedly, the once daily treated group had significantly more corpora lutea per animal (8.1 vs. 6.4) than those in the twice daily treated group. In addition, mean ovarian size score per animal increased significantly when pre-treatment scores were compared to those recorded following FSH treatment (laparotomy) in both Treatment (A) and (B), however, the post-treatment ovarian size scores were not different between these groups. When evaluating post-treatment follicular development, the once daily injection group had significantly more smaller follicles (<10 mm) and a greater number of ovulatory size follicles (>10 mm) than the twice daily injection group. Furthermore, viable appearing embryos were recovered from both treatment groups and no adverse reactions were observed with the gelatin carrier vehicle in Treatment (B). Since the once daily FSH injection schedule resulted in a superovulatory response equal to or greater than the twice daily FSH injection schedule, this approach to superovulation should not be overlooked by those involved in bovine embryo transplantation.

Journal Article↗
PubMed1998

Intracytoplasmic sperm injection in the rat.

We applied intracytoplasmic sperm injection (ICSI) to the rat comparing three different sperm injection techniques: conventional setup with a sharp needle bearing a spike (method 1), combination of partial zona dissection (PZD) needle and blunt pipette (method 2) and piezo-injection using a blunt pipette (method 3). We also investigated the timing of sperm pronuclear formation after injection. Survival rates after injection were 8%, 24% and 71% for the methods 1, 2 and 3, respectively. All surviving oocytes formed pronuclei by about 6 h after injection. Although the survival and activation rates following sperm injection using piezo-injection were high, the incidence of normal fertilisation, as evidenced by second polar body extrusion and formation of two pronuclei, was only 10%. The vast majority of the zygotes were multinucleated, although most of them subsequently underwent cleavage. Fixation and staining of injected oocytes at different times after injection revealed that replacement of sperm nuclear protamines by histones takes place by 15 min after injection, sperm head swelling occurs within 0.5-1 h after injection and pronuclei become fully developed by 7 h after injection. Although the rate of normal fertilisation in the rat following ICSI was low under the present experimental conditions, the results indicated that direct ICSI using a piezo-driven pipette would be a potentially valuable method of producing rat offspring.

Animals↗
PubMedDate not supplied

Seroconversion issues among out-of-treatment injection drug users.

Many risk factors for HIV incidence among drug users have been reported in the literature. However most of these studies have been with local samples, and typically have had limited sample sizes. The National Institute on Drug Abuse (NIDA) funded a Cooperative Agreement for AIDS Community-Based Outreach/Intervention Research (CA) since 1991 that produced a national database. Associations found in the literature were tested to determine whether they were replicated on this national database. The CA national database had complete data, including blood draws six months apart, on 6,970 drug users who were seronegative at baseline. Sites that had no seroincident cases were excluded from the analysis. Twenty-nine risk factors identified in the literature were tested on the national database on a bivariate basis. There were 56 seroincident cases (those who were HIV-seronegative at baseline and HIV-seropositive at follow-up) out of 3752 person years at risk, for a seroconversion rate of 1.49 (CI 1.05, 1.94) per 100 person years at risk. Data were analyzed both as a whole dataset and with the sites stratified by high and low prevalence. In the overall analysis, risk factors associated with seroconversion were times injected any drug, ever injected any drug, days injected cocaine, times injected cocaine, and times injected speedball (these variables had a 30-day time referent). Also significant was how recently formerly-used injection equipment was used. High-prevalence sites revealed associations for times injected any drug, days injected cocaine, and times injected speedball. Low-prevalence sites revealed associations for injected any drug and days injected cocaine. These findings highlight the importance of injection drug use, especially cocaine injection, as a major risk factor in recent seroconversion.

Adult↗
PubMed1975

Effects of intracellular injection of calcium buffers on light adaptation in Limulus ventral photoreceptors.

The calcium sequestering agent, EGTA, was injected into Limulus ventral photoreceptors. Before injection, the inward membrane current induced by a long stimulus had a large initial transient which declined to a smaller plateau. Iontophoretic injection of EGTA tended to prevent the decline from transient to plateau. Before injection the plateau response was a nonlinear function of light intensity. After EGTA injection the response-intensity curves tended to become linear. Before injection, bright lights lowered the sensitivity as determined with subsequent test flashes. EGTA injection decreased the light-induced changes in sensitivity. Ca-EGTA buffers having different levels of free calcium were pressure-injected into ventral photoreceptors; the higher the level of free calcium, the lower the sensitivity measured after injection. The effects of inotophoretic injection of EGTA were not mimicked by injection or similar amounts of sulfate and the effects of pressure injection of EGTA buffer solutions were not mimicked by injection of similar volumes of pH buffer or mannitol. The data are consistent with the hypothesis that light adaptation is mediated by a rise of the intracellular free calcium concentration.

Adaptation, Ocular↗
PubMed1997

Intracytoplasmic injection of spermatids retrieved from testicular tissue: influence of testicular pathology, type of selected spermatids and oocyte activation.

Spermatid microinjection into oocytes has proven to be a successful assisted reproduction procedure in the animal model and in the human species, since in the latter a few full-term pregnancies were actually obtained. Patients entering our spermatid injection study included those with a total absence of spermatozoa in the testicular tissue notwithstanding previous positive biopsies (n = 29): an obstructive problem (n = 3), secretory azoospermia (n = 26), and those with total arrest at the spermatogenesis level in previous explorative biopsies (n = 15). In the latter group, absence of spermatids was recorded in four cases. Mature, elongated, elongating and round spermatids (ROS) were injected in respectively 3, 2, 3, and 32 attempts. A total of 260 metaphase II oocytes were injected with ROS, 36 oocytes with spermatids at other stages of maturity. The rates of oocytes showing two pronuclei (2PN) and two polar bodies reached 22% and 64% respectively after injection of round or elongated-mature spermatids. The fertilization rate after ROS injection was influenced by the percentage of spermatozoa observed in a previous biopsy. Patients with a positive preliminary biopsy had significantly more 2PN (33%) when compared to those with a severe spermatogenic dysfunction and in whom no spermatozoa were found (only 11%) (P < 0.05). Incubation of oocytes in calcium ionophore after ROS injection had a positive effect on the rate of 2PN formation (36 versus 16%). Ninety per cent of all the normally fertilized oocytes cleaved. The percentage of grade A and B embryos depended on the type of injected cells: 12% after ROS and 30% with the other types of haploid cells. A total of 39 transfers resulted in five pregnancies: three full term with healthy babies delivered (one after ROS injection, and two after injection of an elongating and a mature spermatid), one 4 months ongoing (after elongating spermatid injection) and one miscarriage at 4 weeks (after elongated cell injection). Compared to our conventional intracytoplasmic sperm injection-testicular sperm extraction (ICSI-TESE) programme, the implantation rate after ROS injection was very low (5.5 versus 10.5%).

Animals↗
PubMed2001

The effects of single or multiple injections on the volume of 0.5% ropivacaine required for femoral nerve blockade.

UNLABELLED: We compared the effects of using a single- or multiple-injection technique on the volume of 0.5% ropivacaine required to block the femoral nerve, in a prospective, randomized, blinded fashion in which 50 premedicated patients received a femoral nerve block with 0.5% ropivacaine by use of a nerve stimulator and either a single- (n = 25) or multiple- (n = 25) injection technique. Muscular twitches were elicited at < or =0.5 mA before anesthetic injection. The designated volume of local anesthetic was equally divided among contraction of the vastus medialis, vastus intermedius, and vastus lateralis for the multiple injections, or it was injected at the contraction of the vastus intermedius with motion of the patella for the single injection. The local anesthetic volumes were varied for consecutive patients by using an up-and-down staircase method; a blinded observer determined the adequacy of nerve blockade (loss of pinprick sensation in the medial, patellar, and lateral portions of the knee, with concomitant block of the quadriceps muscle) 20 min after injection. The mean (95% confidence interval) volume required for blocking the femoral nerve with the multiple-injection technique (14 [12-16] mL) was significantly smaller than that observed with the single injection (23 [20-26] mL) (P = 0.001). According to logistic regression analyses, the 95% effective volumes of ropivacaine required to block the femoral nerve within 20 min after injection were 29 and 21 mL with a single or multiple injection, respectively. We conclude that searching for multiple muscular twitches reduces the volume of 0.5% ropivacaine required to produce blockade of the femoral nerve. IMPLICATIONS: We evaluated the effects of using a single- or multiple-injection technique on the volume of 0.5% ropivacaine required to block the femoral nerve. The 95%effective concentration values for producing the same degree of sensory and motor blockade of the femoral nerve within 20 min after injection were 29 mL after elicitation of a patella twitch and 21 mL when the three main branches of the femoral nerve were identified, potentially leading to an important benefit for patients receiving peripheral nerve blocks.

Adolescent↗
PubMed1989

Subarachnoid injection--a potential complication of retrobulbar block.

This study was undertaken to illustrate the potential for subarachnoid injection during retrobulbar block as a cause of respiratory arrest. Cadaver orbits were used to document the connection between the optic nerve sheath and the subarachnoid space. Following dissections of the orbits on one side of 24 cadavers, the optic nerve sheaths were identified and injected with 0.5 ml of water for measurement of pressure generated during injection. This was followed by intrasheath injection of equal volume of methylene blue for demonstrating the subarachnoid space surrounding the optic nerves. All injections were performed with a 1-ml syringe with a one-and-one-half-inch 22-G needle over a period of 10 s. The blue dye was found to track along the subarachnoid space of the optic nerve sheath to the chiasmatic cistern in the middle cranial fossa. Retrobulbar injections were performed on the contralateral undissected orbits and intrascleral injections were performed on undissected eyes. The size of the syringes, the gauge of the needles, and the speed of injection were uniform for all injections. The pressure generated by injection into the optic nerve sheath or intrascleral injection (approximately 138 mmHg) was three- to fourfold that produced by injection into the retrobulbar adipose tissue (approximately 35 mmHg) (P less than 0.05). The authors conclude that any resistance encountered during retrobulbar block should serve as a warning signal, mandating redirection of the needle, in order to prevent subarachnoid injection.

Anesthetics, Local↗
PubMed1995

Correlates of hepatitis C virus infections among injection drug users.

Injection drug users are at high risk for hepatitis C virus (HCV) infection. In Baltimore, Maryland, the prevalence of anti-HCV is greater among injection drug users who are black, human immunodeficiency virus (HIV) infected, have injected longer, have injected more frequently, and have injected cocaine than among other injection drug users. HCV infection occurs quickly after the initiation of injecting illicit drugs, with 78% of study participants anti-HCV positive after 2 years of injecting. The prevalence of anti-HCV among injection drug users does not appear to be related to socioeconomic factors or sexual practices. Some injection drug users remain free of anti-HCV even after years of injecting and serologic evidence of other bloodborne pathogens. Some of these injection drug users have HCV infection, demonstrated by HCV RNA in their sera. However, the basis for viral persistence in the absence of anti-HCV and for the absence of HCV infection in long-term drug users is not known. Further studies are indicated to determine the mechanism or mechanisms for the absence of anti-HCV in persons exposed to the virus, because the biologic basis for this condition may elucidate the elements missing in the immune response of the majority of HCV-exposed persons who acquire persistent infection. In addition, interventions to prevent HCV infections should be applied in populations at risk for injection drug use early or before drug use begins.

Adolescent↗