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Plasma concentrations and hemodynamic changes after repeated interpleural injections of bupivacaine-epinephrine.

BACKGROUND AND OBJECTIVES: The purpose of this investigation was to study the arterial plasma concentrations of bupivacaine and the hemodynamic changes after interpleural injection of 20 ml 0.5% bupivacaine with epinephrine in patients treated by chest drainage for spontaneous pneumothorax. METHODS: Twenty-two patients with spontaneous pneumothorax planned to be treated by chest drainage were randomly allocated to a bupivacaine group and a control group receiving saline. After introduction of the chest drain and evacuation of the pneumothorax, 10 injections through an interpleural catheter were given at 8-hour intervals in a double-blind fashion. Plasma concentrations were determined at 5, 10, 20, 30, 240, and 480 minutes after the first injection and before and at 15 and 30 minutes after the 4th, 7th, and 10th injections. Heart rate and mean arterial pressure was registered before and at 15 and 30 minutes after each injection. RESULTS: Mean Cmax after the first injection was 1.02 +/- 0.24 microgram/ml at 15 minutes, the highest individual Cmax after 20 minutes being 1.56 micrograms/ml. Mean plasma concentrations increased up to and after the 4th injection but did not rise further after the 7th and 10th injections. The highest individual Cmax was 1.92 micrograms/ml at 15 minutes after the 10th injection. The injections were accompanied by a small but statistically significant reduction in mean arterial blood pressure and a rise in heart rate 15 minutes after injection in the bupivacaine group compared with the control group. CONCLUSIONS: Repeated interpleural bolus injections of 20 ml 0.5% bupivacaine-epinephrine at 8-hour intervals are safe regarding plasma concentrations of bupivacaine. Small but statistically significant hemodynamic changes can be noticed, probably the result of beta- adrenergic stimulation by epinephrine.

Adult↗

Corticosteroid injections for lateral epicondylitis: a systematic overview.

BACKGROUND: Lateral epicondylitis (tennis elbow) is a common complaint, for which corticosteroid injections are a frequently applied therapy. However, there were no up-to-date reviews available that systematically addressed the effectiveness and adverse effects, including questions concerning optimal timing of injections and composition of the injection fluid. AIM: The aim of the study was to assess the effectiveness of corticosteroid injections in the treatment of lateral epicondylitis (tennis elbow) by systematic review of the available randomized clinical trials. DATA SOURCES: The data sources used were randomized clinical trials identified by literature searches of the MedLine (1966-1994) and Embase (Exerpta Medica) (1980-1994) databases for the keywords epicondylitis, tendinitis and elbow, injection. References given in relevant publications were further examined. STUDY SELECTION: The criteria for selecting studies were as follows: randomized clinical trials (treatment allocation in random or alternate order); one of the treatments to include one or more corticosteroid injections (additional interventions were allowed); participants suffering from lateral epicondylitis; and publication in English, German or Dutch. Abstracts and unpublished studies were not included. DATA SYNTHESIS: Methodological quality was assessed by means of a standardized criteria list (range 1-100 points). The extracted outcomes were the general conclusion drawn by the authors of the reports on the trials, and the success rates at the various follow-up points as (re)calculated by us. The success rates were subsequently graphically displayed and statistically pooled. Separate stratified analyses were conducted according to a predetermined analysis plan. RESULTS: Twelve randomized clinical trials were identified. The median methodological score was 40 points, indicating an overall poor to moderate quality. The pooled analysis indicated short-term effectiveness (2-6 weeks): pooled odds ratio (OR) = 0.15 [95% confidence interval (CI) 0.10-0.23], chi 2 [degrees of freedom (df = 5) = 13.3], indicating statistical heterogeneity. At longer term follow-up, no difference could be detected. The studies of better methodological quality indicated more favourable results than those of lesser methodological quality. The most suitable corticosteroid to use as well as dosage, injection interval and injection volume could not be derived from the various trials. CONCLUSION: The existing evidence on corticosteroid injections for the treatment of tennis elbow is not conclusive. Many trials were conducted in a secondary care setting and clearly had serious methodological flaws, and there was statistical heterogeneity among the trials. Corticosteroid injections appear to be relatively safe and seem to be effective in the short term (2-6 weeks). Although the treatment seems to be suitable for application in general practice, further trials in this setting are needed. As yet, questions regarding the optimal timing, dosage, injection technique and injection volume remain unanswered.

Adrenal Cortex Hormones↗

Autogenous fat intracordal injection as treatment for unilateral vocal palsy.

BACKGROUND: Intracordal injection, which is less time-consuming and avoids neck incision, remains an important method to correct glottic insufficiency induced by unilateral vocal palsy. Among the various new materials proposed for intracordal injection, autogenous fat draws our attention for its availability without cost and high bio-compatibility. This article reports our preliminary experiences of intracordal injection using autogenous fat to treat glottic insufficiency induced by unilateral vocal palsy. METHODS: Autogenous fat is collected under local anesthesia by syringe aspiration from femoral or lower abdomen. Precautions to reduce resorption are taken while collecting and processing the fat. Under the guidance of flexible laryngovideostroboscopy, Bruning syringe with a bended needle is inserted transorally to make the intracordal injection. Serial pre-operation and postoperation evaluations by flexible laryngovideostroboscopy, the patient's selfassessment on the voice, the speech pathologist's perceptual ratings on the breathiness and roughness of the patient's voice, maximum phonation time, and mean airflow rate are made. RESULTS: A total of 19 cases were recruited for the treatment, and 17 of them completed the procedure. The clinical applicability was 89.5%. The fat injection had no obvious effect on the posterior glottic gap correction. The postoperative glottic gap estimated by the videostroboscopy, was improved in 15 of the 16 cases two weeks after operation, and in five of the seven cases who has been followed up for three months. Twelve of the 16 cases felt improved voice in two postoperative weeks, and six of the seven cases still felt the improvement three months after operation. The rate and amount of resorption varied greatly among individuals. None of the injected cords showed untoward morphological or vibratory changes up to three months after injection. CONCLUSIONS: Intracordal injection of autogenous fat to treat unilateral vocal palsy by the method we propose is relatively simple with high clinical applicability and no extra-cost. None of the injected cords showed unfavorable changes. Most of the patients were improved after injection, at least for a short period of time. The long-term effectiveness remains to be observed. Repetition of the injection is also simple, if the voice results deteriorate due to resorption of the injected fat.

Adolescent↗

[A study on behavior towards injection among residents and physicians in Kaohsiung & Ping-tung area].

To understand why people in Taiwan preferred iatrogenic injection as their medical therapy, we surveyed the knowledge, attitude, and behavior of iatrogenic injection for people and doctors in Kaohsiung and Ping-tung area by questionnaire. The results of the survey are drawn below: 1. More than 91.7% of the interviewed people would like to receive iatrogenic injection as their medical therapy, and 78.1% of the parents would choose iatrogenic injection for their children. The reason majority were because doctors suggested that and the parents believed iatrogenic injection is a quicker way of recovery. 2. In this study, 72.1% of the people received injection as their usual mode of medical treatment, and 74.9% of them had received injection during the previous month. When they brought their children to the clinics, the percentages of the above two conditions were 60.4% and 59.7% respectively. The factors influencing the reception of injection for people were the efficacy of the injection, education level and medical insurance. The influencing factors for children were the parents' medical behavior and the parents' willingness to accept injection. 3. About 83% of the interviewed doctors preferred iatrogenic injection as treatment for their patients. Almost 60% of them agreed that more patients would receive injection after National Health Insurance. About 72% of the doctors would not change the treatment for their patients, no matter how the system of the medical insurance changes. They would choose the right treatment for the distinct disease.

Adult↗

[Selective segmental necrotizing therapy for hepatocellular carcinoma: an experimental study of an ethanol injection method].

Selective segmental necrotizing therapy (SSN), which necrotizes the hepatic segment by ethanol injection through the intrahepatic portal vein under balloon occlusion, is a new treatment for hepatocellular carcinoma. To better perform this therapy safely and completely, the author examined an ethanol injection method using rabbits. A discolored area immediately formed in the injected area following rapid injection (injection speed > or = 1.0 ml/s) of absolute ethanol. This area became larger with increasing ethanol volume until it reached a plateau. The author defined the minimal volume as the minimal ethanol volume needed to form the maximal discolored area. The minimal volume correlated with the portal branch diameter of the injected area. A discolored area also formed when 50% or 25% ethanol was given by slow injection (injection speed < or = 0.1 ml/s), similar to the case of using absolute ethanol by rapid injection. The area was recognized as a necrotic area on histological examinations 14 days after SSN. The blood ethanol level in the right atrium showed the slightest elevation when 25% ethanol was given by slow injection. GPT showed the highest elevation 1 day after SSN, but it returned to normal 7 days after SSN in all ethanol injection methods. From these results, the author concluded that SSN should be performed using 25% ethanol by slow injection.

Animals↗

Vaccination against cutaneous leishmaniasis in mice using nonpathogenic cloned promastigotes of Leishmania major and importance of route of injection.

In vaccination studies, mice have been injected by different routes with living promastigotes of nonpathogenic leishmania followed by cutaneous challenge with pathogenic promastigotes. Parasites used for vaccination have been promastigotes of the cloned parasite lines A12 and A52 derived from Leishmania major isolate L137, or long-term cultured promastigotes of the leishmaniasis recidiva isolate, L32 (L.t.tropica). None of these protozoa causes lesions after cutaneous injection to mice. Disease in previously injected mice has been monitored after cutaneous challenge with promastigotes of a virulent cloned line, V121, derived from isolate L137. Mice used were C57BL/6 (genetically resistant), BALB/c and BALB/c.H-2b (genetically susceptible) and BALB/c.H-2k (also genetically susceptible but sometimes less so than BALB/c). C57BL/6 mice were almost completely resistant to subsequent cutaneous disease when challenged after intraperitoneal injection of viable nonpathogenic cloned promastigotes. In contrast, BALB/c, BALB/c.H-2b and BALB/c.H-2k mice challenged after intravenous or intraperitoneal injection were only protected partially against cutaneous leishmaniasis. These vaccinated mice generally showed persistent low grade cutaneous disease for many months after challenge. High doses of viable L32 promastigotes injected intraperitoneally were also able to induce a degree of resistance to subsequent cutaneous leishmaniasis. Using any protocol, subcutaneous injections have been totally without protective effects as have been killed promastigotes injected by any route to mice. Subcutaneous injections appear to be ineffective rather than counterproductive in that mice injected by both the intravenous and subcutaneous routes with nonpathogenic living cloned promastigotes resemble mice injected by the intravenous route in their disease status following challenge.

Animals↗

Intracytoplasmic injection of porcine, bovine, mouse, or human spermatozoon into porcine oocytes.

We determined the incidence of activation, male pronuclear formation, and apposition of pronuclei in porcine oocytes following intracytoplasmic injection of various porcine sperm components and foreign species spermatozoa, such as that of cattle, mouse or human. The porcine oocytes were activated by injection of a spermatozoon or an isolated sperm head. In contrast, injection of either sperm tail or a trypsin- or NaOH-treated sperm head failed to induce oocyte activation. Because injection of mouse, bovine, or human spermatozoon activated porcine oocytes, the sperm-borne activation factor(s) is not strictly species-specific. Male pronuclear formation and pronuclear apposition were observed in porcine oocytes following injection of porcine, bovine, mouse or human spermatozoa. Electrical stimulation following sperm cell injection did not enhance the incidence of male pronuclear formation or pronuclear apposition compared with sperm cell injection alone (P > 0.1). Following porcine sperm injection, the microtubular aster was organized from the neck of the spermatozoon, and filled the whole cytoplasm. In contrast, following injection of bovine, mouse, or human spermatozoon, the maternal-derived microtubules were organized from the cortex to the center of the oocytes, which seems to move both pronuclei to the center of oocytes. Cleavage to the two-cell stage was observed at 19-21 hr after injection of porcine spermatozoon. However, none of the oocytes following injection of mouse, bovine, or human spermatozoa developed to the mitotic metaphase or the two-cell stage. These results suggested that the oocyte activating factor(s) is present in the perinuclear material and that it is not species-specific for the porcine oocyte. Self-organized microtubules seemed to move the pronuclei into center of oocytes when foreign species spermatozoa were injected into porcine oocytes.

Animals↗

Effect of muscle activity immediately after botulinum toxin injection for writer's cramp.

Animal and human studies have shown that nerve stimulation enhances some effects of botulinum toxin (btx A) injection. Voluntary muscle activity might work similarly and would focus the effect of an injection into the active muscles. We studied the effects of exercise immediately after btx A injection in eight patients with writer's cramp with established response to btx A over two injection cycles with a single-blinded, randomized, crossover design. Immediately after the first study injection, they were randomly assigned to write continuously for 30 min or have their hand and forearm immobilized for 30 min. Following the second injection, they were assigned the alternate condition. Patients were assessed just before each injection, and at 2 weeks, 6 weeks, and 3 months post-injection. Assessment included objective strength testing, self-reported rating of benefit and weakness, and blinded evaluation of videotapes and writing samples of the patients writing a standard passage. Strength testing showed that the maximum weakness occurred at 2 weeks post-injection, but the benefit was maximum at 6 weeks post-injection. The "write" condition resulted in greater reduction in strength than the "rest" condition. Btx A treatment led to improvement in self-reported ratings, writer's cramp rating scale scores by blinded raters, and reduction in writing time, but the differences between the "write" and "rest" conditions were not significant. We conclude that voluntary muscle activity immediately after btx A injection leads to greater reduction in muscle strength. Our findings raise the possibility that voluntary muscle activation may allow reduction of btx A doses and favorably alter the balance of benefit and side effects of btx A injections.

Adult↗

Intrathymically injected hemopoietic stem cells can differentiate into all lineage cells in the thymus: differences between c-kit+ cells and c-kit < low cells.

To investigate whether hemopoietic stem cells (HSCs) can differentiate into all lineage cells even in the thymus, we injected two types of HSCs (c-kit+ and c-kit < low cells) obtained from C57BL/6 Ly5.1 mice directly into the thymus of 7.5 Gy-irradiated C57BL/6 Ly5.2 mice. When c-kit < low cells (low density/lineage-/CD71-/major histocompatibility complex class I high/Sca-1+/Thy-1low/ c-kit < low) were injected, donor-derived (Ly5.1) cells were detected on day 8 after intrathymic (i.t.) injection, and the number reached a maximum on day 24 after injection. Granulocytes and macrophages were also detected on day 8 after injection. However, B220+ B cells were observed on day 13. Eighteen days after i.t. injection, the injected lobes showed red color due to the synchronous development of erythroid cells. Histological studies revealed the development not only of erythroid lineage cells but also of megakaryocytes in the thymus. In contrast, when c-kit+ cells were injected, a significant number of donor-derived cells were detected on day 5 after i.t. injection (three days earlier than in the case of c-kit < low cell injection). The differentiation into erythroid lineage cells was also observed six days earlier than when c-kit < low HSCs were injected. These findings suggest that c-kit < low HSCs are more primitive than c-kit+ HSCs, although both can differentiate into all lineage cells after i.t. injection.

Animals↗

Epidural administration and analgesic spread: comparison of injection with catheters and needles.

This study was designed to investigate differences in epidural analgesic spread between catheter and needle injections in 48 patients with comparable physical characteristics. The spread of analgesia in the catheter injection group with a 0.24 ml.sec(-1) injection rate (n = 16) was 16.8 +/- 1.5 spinal segments and that in the needle injection group at the same injection rate (n = 16) was 12.5 +/- 1.8 spinal segments ( P < 0.01). Needle injection at the faster rate of 1.2 ml.sec(-1) (n = 16) produced a significantly greater spread of analgesia than with the 0.24 ml.sec(-1) rate through the needle (16.2 +/- 1.6 vs 12.5 +/- 1.8 spinal segments, P < 0.01). Thirteen of 16 patients receiving the fast needle injection complained of back compression or discomfort during the injection. The injection through an epidural catheter and the fast (1.2 ml.sec(-1)) injection through a needle produced extensive and equivalent epidural analgesic spread. However, because of patients discomfort with fast injection through the needle, the authors conclude that when using continuous epidural anesthesia, the initial injection of local anesthetic should be administered through the epidural catheter not the needle.

Journal Article↗

Activation of osmotically-activated potassium transporters after injection of mRNA from A6 cells in Xenopus oocytes.

The different potassium pathways, under iso-osmotic or hypo-osmotic conditions, were examined in Xenopus oocytes that were micro-injected with mRNA from A6 cells. Hypo-osmotically stimulated 86Rb (K+) effluxes could be measured from intact oocytes 1-4 days after injection of 25 ng of poly (A)+ RNA isolated from A6 cells. 86Rb (K+) effluxes were 2.2 times higher from oocytes micro-injected with 25 ng of poly(A)+ RNA, than from water injected control oocytes. Water-injected oocytes themselves, however, were 7-fold more responsive to a hypo-osmotic shock than non-injected Xenopus oocytes. There was no significant effect of the different K+ transport blockers tested (TEA, bumetanide, glybenclamide or quinidine) on the endogenous 86Rb (K+) effluxes from non-injected oocytes in either iso- or hypo-osmotic media. The 86Rb (K+) effluxes from water-and mRNA-injected oocytes in hypo-osmotic media were both inhibited by TEA. In mRNA-injected oocytes the increase in 86Rb (K+) transport following a medium dilution was also inhibited in the presence of glybenclamide or bumetanide. The present study reports that the activation of hypo-osmotically-activated potassium transporters in the oocytes of Xenopus laevis. after injection of mRNA from A6 cells differs quantitatively and in part qualitatively (glybenclamide-sensitivity) from the endogenous K+ pathways of non-injected and of water-injected Xenopus oocytes.

Animals↗

Defective DNA injection by alkylated and nonalkylated bacteriophage T7.

DNA injection by alkylated and nonalkylated bacteriophage T7 has been analyzed by a physical method which involved Southern hybridization to identify noninjected regions of DNA. Treatment of phage with methyl methanesulfonate reduced the amount of DNA injected into wild-type Escherichia coli cells. This reduction was correlated with a decreased injection of DNA segments located on the right-hand third of the T7 genome. An essentially identical injection defect was observed when alkylated phage infected E. coli mutant cells unable to repair 3-methyladenine. Furthermore, untreated phage particles were discovered to be naturally injection-defective. Some injected all their DNA except those segments located in the rightmost 15% of the T7 genome, while other injected no DNA at all. In the presence of rifampicin, untreated phages injected only segments from the left end of the genome. These results provide direct physical evidence that T7 DNA injection is strictly unidirectional, starting from the left end of the T7 genome. The injection defect quantified here for alkylated phage is probably partially, if not totally, responsible for phage inactivation, when that inactivation is measured in wild-type E. coli cells. Since alkylated phage injected the same DNA sequences into both wild-type and repair-deficient cells, we conclude that DNA injection is independent of the host-cell's capacity for repair of 3-methyladenine residues.

Adenine↗

Moxonidine and rilmenidine injected into the medial septal area reduces the salivation induced by pilocarpine.

We determined the effects of moxonidine and rilmenidine 20 nmol (alpha(2)-adrenergic and imidazoline receptor agonists) injected into the medial septal area (MSA) on the pilocarpine-induced salivation, when injected intraperitoneally (i.p.), of male Holtzman rats weighing 250-300 g, with stainless-steel cannula implanted into the MSA. The rats were anesthetized with zoletil 50 mg kg(-1) b.wt. (tiletamine chloridrate 125.0 mg and zolazepan chloridrate 125.0 mg) into quadriceps muscle intramuscularly (IM), saliva was collected using pre-weighed small cotton balls inserted in the animal's mouth. The pre-treatment with moxonidine injected into the MSA reduced the salivation induced by pilocarpine (1 mg kg(-1)) injected i.p. (12+/-3 mg min(-1)) vs. control (99+/-9 mg min(-1)). The pre-treatment with rilmenidine 40 nmol also reduced the salivation induce by pilocarpine injected i.p. (20+/-5 mg min(-1)) vs. control (94+/-7 mg min(-1)). Idazoxan 40 nmol (imidazoline receptor antagonist) injected into the MSA previous to moxonidine and rilmenidine partially blocked the effect of moxonidine and totally blocked the rilmenidine effect in pilocarpine-induced salivation injected i.p. (60+/-8 and 95+/-10 mg min(-1), respectively). Yohimbine 40 nmol (alpha(2)-adrenergic receptor antagonist) injected into the MSA previously to moxonidine and rilmenidine partially blocked the moxonidine effect but produced no change on the rilmenidine effect on i.p. pilocarpine-induced salivation (70+/-6 and 24+/-6 mg min(-1), respectively). Injection of these alpha(2)-adrenergic and imidazoline agonists and antagonists agents i.p. produced no change on i.p. pilocarpine-induced salivation. These results show that central, but not peripheral, injection of alpha(2)-adrenergic and imidazoline agonists' agents inhibit pilocarpine-induced salivation. Idazoxan, an imidazoline receptor antagonist, totally inhibits the rilmenidine effect and partially inhibits the moxonidine effect on pilocarpine-induced salivation. Yohimbine produced no change on rilmenidine effect but partially inhibited the moxonidine effect. Both of these antagonists when injected into the MSA previous to pilocarpine i.p. potentiated the sialogogue effect of pilocarpine. The results suggest that alpha(2)-adrenergic/imidazoline receptor of the MSA when stimulated blocked pilocarpine-induced salivation in rats when injected intraperitonially. These receptors of the medial septal area have an inhibitory mechanism on salivary secretion.

Adrenergic alpha-Agonists↗

Prevalence of injecting drug use and associated risk behavior among regular ecstasy users in Australia.

BACKGROUND: The aim of the study was to investigate the prevalence of injecting drug use and associated risk behaviour among a sentinel sample of ecstasy users. METHODS: Cross-sectional surveys were conducted with regular ecstasy users as part of an annual monitoring study of ecstasy and related drug markets in all Australian capital cities. RESULTS: Twenty-three percent of the sample reported having ever injected a drug and 15% reported injecting in the 6 months preceding interview. Independent predictors of lifetime injection were older age, unemployment and having ever been in prison. Completion of secondary school and identifying as heterosexual was associated with a lower likelihood of having ever injected. Participants who had recently injected typically did so infrequently; only 9% reported daily injecting. Methamphetamine was the most commonly injected drug. Prevalence of needle sharing was low (6%), although half (47%) reported sharing other injecting equipment in the preceding 6 months. CONCLUSIONS: Ecstasy users who report having injected a drug at some time appear to be demographically different to ecstasy users who have not injected although neither are they typical of other drug injectors. The current investigation suggests that ongoing monitoring of injecting among regular ecstasy users is warranted.

Adult↗

Subareolar injection is a better technique for sentinel lymph node biopsy.

BACKGROUND: Numerous techniques and materials show accuracy in localizing the sentinel lymph node (SLN). We hypothesized that subareolar injection of material would localize the SLN as effectively as peritumoral injection. METHODS: Thirty-eight patients were injected with technetium-99 sulfur colloid either peritumorally or subareolarly in addition to the injection of blue dye around the tumor. Radioactive SLNs were localized using a hand-held gamma probe. RESULTS: Nineteen patients were included in each of the two groups, peritumoral and subareolar. SLNs were found in all patients injected subareolarly and in 18 of 19 injected peritumorally. The false-negative rate was 20% for peritumoral injection and 0% for subareolar injection. CONCLUSION: The results suggest that subareolar injection was as accurate, if not more accurate, than peritumoral injection for localizing the SLN. This technique is simpler than peritumoral injection and does not require injection under image guidance for nonpalpable lesions.

Adult↗

Differential effector functions of central and peripheral compartments of immune response system: characterization of immune responses in the spleen and mesenteric lymph nodes to directly injected sheep red blood cells.

When sheep red blood cells (SRBC) were injected intraperitoneally (i.p.), intravenously (i.v.), or into the Peyer's patches, definite plaque-forming cell (PFC) and rosette-forming cell (RFC) responses were induced in the spleen but not in the mesenteric lymph nodes (MLN). When SRBC were injected directly into the spleen or MLN, stronger PFC and RFC responses were induced in the spleen or MLN, respectively, than when injected i.p. or i.v. PFC response induced in MLN by injecting SRBC into MLN with or without the polysaccharide of Klebsiella pneumoniae type 1 Kasuya strain (CPS-K) as an immunological adjuvant was weaker than that induced in the spleen by injecting the antigen into the spleen. Direct PFC (PFC of IgM type) and RFC responses induced in the spleen by injecting SRBC into MLN were rather stronger than those induced in the spleen by injecting the antigen into the spleen. In contrast, no significant responses were induced in MLN by injecting SRBC into the spleen, and no definite indirect PFC (PFC of IgG type) response was induced in the spleen by injecting the antigen into MLN. The levels of whole immunological memory as well as isolated B- or T-cell memory in the spleen and MLN of mice injected with SRBC directly into the spleen or MLN were determined by using an in vitro assay system. Definite amounts of either B- or T-cell memory were detected in the spleen of mice injected with SRBC directly into the spleen of MLN. Smaller amounts of memory were detected in MLN injected with SRBC directly into the spleen. Moreover, the amounts of whole memory detected in MLN were much less than compared with those of isolated T- and B-cell memories in MLN. Further experiments showed that in vitro expression of the memories preserved in MLN required supplement of glass non-adherent cells from normal spleen. Based on these results, we discussed the possible differential and collaborative functions of the central (spleen) and peripheral (MLN) immune response systems in antibody responses.

Animals↗

The histologic fate of autologous collagen injected into the canine vocal fold.

Collagen is a functionally essential component of the five-layered structure of the vocal fold. Soluble bovine collagen has previously been shown to be an effective injectable bioimplant for vocal fold defects, paralysis, and, especially, scarred larynges. Although bovine collagen appears to be well tolerated, the concern for possible adverse immunologic responses has deterred approval from the Food and Drug Administration for its clinical use in the larynx. Currently we are investigating the use of injectable autologous collagen for vocal fold augmentation. The purpose of this study is to examine the histologic fate of autologous collagen injected into the canine vocal fold at multiple intervals after injection. An ellipse of skin measuring 3 x 6 cm was harvested from each of three dogs and processed into a naturally cross-linked injectable solution of collagen (Autologen). This autologous collagen was injected into one vocal fold and a control injection of buffer solution was injected contralaterally. The injections were well tolerated and no dog appeared to suffer any immediate or delayed ill effects. The dog larynges were harvested 1, 3, and 6 months after collagen injection and examined grossly and histologically. Injected autologous collagen material persisted in these experimental animals and appeared to be well tolerated. Based on this preliminary study, we anticipate autologous collagen to be at least as suitable as bovine chemically cross-linked collagen as an injectable bioimplant for vocal fold augmentation. It may also have the advantage of added safety and stability.

Animals↗

Electrokinetic injection for stacking neutral analytes in capillary and microchip electrophoresis.

An on-column mechanism for electrokinetically injecting long sample plugs with simultaneous stacking of neutral analytes in capillary electrokinetic chromatography is presented. On-column stacking methods allow for the direct injection of long sample plugs into the capillary, with narrowing of the analyte peak width to allow for an increase in the detected signal. Low-pressure injections (approximately 50 mbar) are commonly used to introduce sample plugs containing neutral analytes. We demonstrate that injection can be accomplished by applying an electric field from the sample vial directly into the capillary, with neutral analytes injected by electroosmotic flow at up to 1 order of magnitude faster than the corresponding pressure injections. Since stacking occurs simultaneously with electrokinetic injection, stacking is initiated at the capillary inlet, resulting in an increased length of capillary remaining for separation. Reproducibility obtained for peak height and peak area with electroosmotic flow injection is comparable to that obtained with the pressure injection mode, while reproducibility of analysis time is markedly improved. Electrokinetic stacking of neutral analytes utilizing electroosmotic flow is demonstrated with discontinuous (high conductivity, high mobility) as well as continuous (equal conductivity, equal mobility) sample electrolytes. Injecting neutral analytes by electroosmotic flow affords a 10-fold or greater decrease in analysis times when capillaries of 50-microm i.d. or smaller are used. This stacking method should be exportable to dynamic pH junction stacking and electrokinetic chromatography with capillary arrays. Equations describing this electrokinetic injection mode are introduced and stacking of a neutral analyte on a microchip by electrokinetic injection using a simple cross-T channel configuration is demonstrated.

Journal Article↗