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Iontophoresis of antibiotics into segmental allografts.

Iontophoresis is a novel technique which may be used to facilitate the movement of antibiotics into the substance of bone using an electrical potential applied externally. We have examined the rate of early infection in allografts following application of this technique in clinical practice. A total of 31 patients undergoing revision arthroplasty or surgery for limb salvage received 34 iontophoresed sequential allografts, of which 26 survived for a minimum of two years. The mean serum antibiotic levels after operation were low (gentamicin 0.37 mg/l (0.2 to 0.5); flucloxacillin 1 mg/l (0 to 1) and the levels in the drains were high (gentamicin 40 mg/l (2.5 to 131); flucloxacillin 17 mg/l (1 to 43). There were no early deep infections. Two late infections were presumed to be haemotogenous; 28 of the 34 allografts were retained. In 12 patients with pre-existing proven infection further infection has not occurred at a mean follow-up of 51 months (24 to 82).

Adolescent↗

Electroosmosis in transdermal iontophoresis: implications for noninvasive and calibration-free glucose monitoring.

Reverse iontophoresis uses a small low electric current to noninvasively extract blood analytes, e.g., glucose, across the skin. The simultaneous quantification of the analyte extracted and of an additional endogenous substance of fixed and known concentration in the body permits the blood level of interest to be found without the need for an invasive calibration procedure. The transport phenomena underlying this approach, applied to glucose monitoring, has been investigated in vitro, using Na+ and neutral model solutes as endogenous "internal standards" (specifically, urea, glycerol, mannitol, and sucrose). The cathodal extracted fluxes of glucose under conditions of modified skin permselectivity were related to those of the different, potential internal standards. Flux ratios depended upon the iontophoretic conditions and the size of the neutral internal standards, whereas high variability was observed with Na+. Constant flux ratios were obtained with mannitol, glycerol, urea, and sucrose for which the mechanism of electrotransport was identical to that of glucose. The advantage of using a neutral internal standard, however, must be weighed against the need to identify and validate the marker under physiological conditions and the additional analytical chemistry necessary for the practical quantification of this substance.

Animals↗

Effectiveness of sodium fluoride on tooth hypersensitivity with and without iontophoresis.

Effectiveness of iontophoresis with and without electric current and sodium fluoride on tooth hypersensitivity was evaluated. In eleven volunteers, teeth received a 2% neutral sodium fluoride solution applied using an electrode phoresor. Test teeth received the solution with current and control teeth received the solution without current. The subjects were tested at Day 0 and 7 by means of a mechanical stimulating device and a temperature probe. The data were then analyzed using X2 analysis. Statistically, the test teeth demonstrated more improvement than the control teeth.

Adult↗

2% sodium fluoride-iontophoresis compared to a commercially available desensitizing agent.

BACKGROUND: Dentin hypersensitivity is a common clinical condition and age-old complaint, presenting problems to both the patient and the dentist. Besides causing discomfort, the condition may deter a person from establishing or maintaining adequate oral hygiene procedures, further complicating oral health. The failure to practice satisfactory plaque control has well-established consequences on gingival and periodontal health. Thus, a cycle of sensitive teeth leading to reduced plaque control, more periodontal disease, and more recession may be established. METHODS: The hypersensitive teeth were identified by the patient and verified by the light stroke of a dental explorer along the cervical area of all teeth present. Subjects fulfilling the inclusion and exclusion criteria were evaluated using tactile, 1-second air blast, and cold water stimuli, and the subject's response was recorded on the verbal rating scale. A total of 425 teeth from 50 patients included in this study were randomly divided into two groups: group 1, who received 2% sodium fluoride-iontophoresis (NaF) and group 2, who received an aqueous solution of hydroxy-ethyl-methacrylate and glutaraldehyde (HEMA-G). The teeth were evaluated immediately after treatment and at 2 weeks, 1 month, and 3 months. In case of failure at the 2-week interval, the affected tooth was retreated with the same drug as before and evaluated further. RESULTS: The results were statistically analyzed, and it was found that group 1 treatment was more effective than group 2 at 1- and 3-month intervals. There was a comparatively greater recurrence of hypersensitivity in group 2. A comparable number of teeth required repeat dosage in both groups. Teeth which required repeat dosage had greater mean discomfort scores at baseline for all three tests than the teeth which did not require a repeat dose. CONCLUSIONS: Both agents showed significant reduction in sensitivity at all time intervals compared to baseline; however, NaF had a comparatively greater effect than HEMA-G at both the 1- and 3-month intervals; an almost equal number of teeth in both groups required repeat doses. Teeth with a higher initial sensitivity score required a repeat dose. Both agents were found to be equally effective immediately after application; the 2% NaF was comparatively better than HEMA-G in providing long-term relief.

Administration, Topical↗

Evaluation of a combined laser Doppler flowmetry and iontophoresis technique for the assessment of equine cutaneous microvascular function.

A combined laser Doppler flowmetry and iontophoresis (LDFI) technique, used routinely to assess human microvascular function, was evaluated as a noninvasive technique for assessment of equine microvascular function, to facilitate the study of diseases such as laminitis. Baseline and vasoactive agonist-induced (acetylcholine and nitroprusside) microvascular flux was quantified at 2 sites (on the dorsal pastern adjacent to the coronary band and over the gluteals) in 6 clinically normal horses on 5 or 6 separate occasions under standardised conditions. Both agonists significantly increased microvascular flux. Skin pigmentation significantly attenuated the baseline flux, but not the magnitude of the agonist-mediated vasodilatory response. While LDFI was simple to perform, its value as a clinical and research tool for assessing the equine cutaneous microcirculation is limited by its poor reliability, as indicated by the marked intra- and intersubject variability in baseline and agonist-mediated microvascular flux.

Acetylcholine↗

Recovery of a latent HSV-1 thymidine kinase negative strain following iontophoresis and co-cultivation in the ocularly-infected rabbit model.

Previous studies in the mouse and guinea pig have reported little or no colonization of sensory ganglia by strains of herpes simplex type 1 failing to express the enzyme, thymidine kinase (TK). The current study in the rabbit demonstrated trigeminal ganglionic colonization and reactivation of a latent thymidine kinase negative strain of HSV-1 by two independent methods: iontophoresis-induced ocular shedding and co-cultivation. Treatment with topical steroids during the acute infection did not enhance the latency rate. Following reactivation, back mutation with phenotypic reversion to thymidine kinase positive was demonstrated in a few recovered isolates. The current study also emphasized the importance of species differences to explain differing experimental results in studies of HSV-1 TK negative latency.

Animals↗

Cystic fibrosis in Korean children:a case report identified by a quantitative pilocarpine iontophoresis sweat test and genetic analysis.

Cystic fibrosis (CF) is inherited as an autosomal recessive trait, and the mutations in cystic fibrosis transmembrane conductance regulator (CFTR) gene contributes to the CF syndrome. Although CF is common in Caucasians, it is known to be rare in Asians. Recently, we experienced two cases of CF in Korean children. The patients were girls with chronic productive cough since early infancy. Chest computed tomography showed the diffuse bronchiectasis in both lungs, and their diagnosis was confirmed by the repeated analysis of a quantitative pilocarpine iontophoresis test (QPIT). The sweat chloride concentrations of the first patient were 108.1 mM/L and 96.7 mM/L. The genetic analysis revealed that she was the compound heterozygote of Q1291X and IVS8 T5-M470V. In the second case, the sweat chloride concentrations were 95.0 mM/L and 77.5 mM/L. Although we performed a comprehensive search for the coding regions and exon-intron splicing junctions of CFTR gene, no obvious disease-related mutations were detected in the second case. To our knowledge, this is the first report of CF in Korean children identified by a QPIT and genetic analysis. The possibility of CF should be suspected in those patients with chronic respiratory symptoms even in Korea.

Blood Pressure↗

Iontophoresis: an alternative drug-delivery system.

Iontophoresis expands the range of drugs that are available for transdermal drug delivery. This article looks at the important advantages this technology offers, such as the ability to rapidly deliver large quantities of large-molecule and water-soluble drugs. Its potential is illustrated in a review of ideal drug candidates and results of trials conducted to date.

Administration, Cutaneous↗

The history of electrically-assisted transdermal drug delivery ("iontophoresis").

The first proposals for the use of electric current in drug delivery date from the mid 18th century. Serious progress was made in the 19th century notably by Benjamin Ward Richardson (1828-1896), Hermann Munk (1839-1912), William James Morton (1846-1920), Stéphane Leduc (1853-1939) and Fritz Frankenhäuser (born 1868). Administration of metal ions as well as alkaloids was tried at that time. Until the early 20th century, current mediated drug delivery was known as "cataphoresis"; Frankenhäuser is said to have introduced the term "iontophoresis" before 1908. Recently, researchers talk about "electrically-assisted transdermal drug delivery". The technique was never widely adopted but always proved useful to some extent in solving particular drug delivery problems. At the dawn of the 21st century, attempts are being made to achieve iontophoretic delivery of peptides and proteins.

Administration, Cutaneous↗

Iontophoresis in vivo demonstrates a key role for GABA(A) and glycinergic inhibition in shaping frequency response areas in the inferior colliculus of guinea pig.

The processing of biologically important sounds depends on the analysis of their frequency content by the cochlea and the CNS. GABAergic inhibition in the inferior colliculus shapes frequency response areas in echolocating bats, but a similar role in nonspecialized mammals has been questioned. We used the powerful combination of iontophoresis with detailed analysis of frequency response areas to test the hypothesis that GABAergic and glycinergic inhibition operating in the inferior colliculus of a nonspecialized mammal (guinea pig) shape the frequency responses of neurons in this nucleus. Our analysis reveals two groups of response areas in the inferior colliculus: V-shaped and non-V-shaped. The response as a function of level in neurons with V-shaped response areas can be either monotonic or nonmonotonic. Application of bicuculline or strychnine in these neurons, to block inhibition mediated by GABA(A) or glycinergic receptors, respectively, increases firing rate primarily within the boundaries of the control response area. In contrast, neurons in the non-V-shaped group have response areas that include narrow, closed, tilted, and double-peaked types. In this group, blockade of GABA(A) and glycine receptors increases firing rate but also changes response area shape, with most becoming more V-shaped. We conclude that (1) non-V-shaped response areas can be generated by GABA and glycinergic synapses within the inferior colliculus and do not simply reflect inhibition acting more peripherally in the pathway and (2) frequency-dependent inhibition is an important general feature of the mammalian inferior colliculus and not a specialization unique to echolocating bats.

Acoustic Stimulation↗

Ocular aspirin distribution: a comparison of intravenous, topical, and coulomb-controlled iontophoresis administration.

PURPOSE: To evaluate the pharmacokinetics and safety of aspirin delivered by a single, noninvasive, transscleral, coulomb-controlled iontophoresis (CCI) treatment; topical application; or by one intravenous (IV) injection. METHODS: Forty-one adult New Zealand White rabbits received either a single IV injection, topical, or CCI administration of aspirin at a concentration of 10 mg/mL. Histologic evaluation was performed in four CCI-treated eyes to assess safety. Pharmacokinetic distribution in all ocular tissues and fluids was studied at 0.5, 1, 2, 4, 6, and 8 hours after the treatments. Immediately after death, the eyes were dissected and salicylic acid (SA) concentration was determined by HPLC analysis. Blood was sampled at 0.5, 1, 2, 4, 6, and 8 hours, and plasma SA levels for systemic distribution were measured by HPLC analysis. RESULTS: No tissue damage was observed clinically or histologically. SA was found in all tissues and fluids throughout the study period of 8 hours. The highest concentrations of SA were observed with CCI immediately after treatment for all tissues and were the highest SA tissue peaks obtained by the studied delivery methods. IV administration demonstrated a delayed tissue peak of salicylate at 2 hours after administration. At 8 hours, ocular SA concentrations were in the same range for CCI and IV administration. IV injection resulted in blood plasma levels up to 28 times higher than CCI and remained significantly elevated until 8 hours after the treatments. CONCLUSIONS: CCI is a safe and effective method of administering aspirin to the eye while avoiding the systemic side effects associated with IV injection.

Administration, Topical↗

[Effects of beta blocking agent iontophoresis by modulated sinusoidal current].

The action of the transcutaneous application of propranolol using modulated sinusoidal current iontophoresis was studied. When this way of administration is used, the drug, while maintaining its negative chronotropic effect, loses the negative inotropic one. Investigations were performed on 58 men aged 32 to 62 who underwent an aortocoronary bypass for myocardial ischemia. Thirty-four patients had already had myocardial infarction. The drug reduced the heart rate and increased cardiac contractility. Moreover, the study showed that only the levogyral isomer of propranolol (the only active one) passes through the skin.

Adrenergic beta-Antagonists↗

An improved apparatus for transscleral iontophoresis of gentamicin.

The authors previously found that positively charged substances are less well-transported into the vitreous humor by transscleral iontophoresis than are negatively charged substances. There was more bubble formation in the eye cup with positively charged than with negatively charged substances. The authors hypothesized that these bubbles might account for the poorer conductance of the positively charged species by causing interruptions of the current. Therefore, the authors developed a modified eye cup in which the diameter of the fluid column was larger than that in the old device (1.0 rather than 0.5 mm). This modification allowed larger voltage to be applied than with the older device, because bubbles could be more easily cleared from the conjunctiva than with the narrower-bore eye cup. Although the efficiency of the apparatus was the same with the two eye cups (micrograms per milliliter in vitreous humor divided by milliampere minutes of current applied), vitreal concentrations of gentamicin with the modified eye cup were fourfold higher than with the older eye cup (83 versus 19 micrograms/ml; P < 0.001). These studies suggest that modifying the eye cup to permit easier removal of bubbles resulted in improved delivery of gentamicin into the ocular humors.

Animals↗

[Iontophoresis of tenoxicam in the therapy of osteoarthrosis].

After a brief physiopathological research about iontophoresis applications, the authors examine this treatment by two drugs (Tenoxicam and acetylsalicylic acid) in a group of patients suffering from painful osteoarthritis. They came to the conclusion that the treatment is efficacious with both substances though realising a quicker analgesic result in the group treated with tenoxicam.

Aged↗

[Influence of calcium channel blockers and beta-blockers on pain relief with iontophoresis].

We studied usefulness of iontophoresis on pain relief using several Ca channel blockers, propranolol and guanethidine. Subjects were 18 healthy adult volunteers. We used 4% lidocaine with/without several drugs (2 mg of nicardipine, verapamil, diltiazem, propranolol and 10mg of guanethidine), and evaluated the pain relief effect with Nakahama's algesimeter. In all groups except for propranolol group, the pain recognition time was elongated significantly in comparison with control. In making comparison between each Ca channel blocker, we did not observe any significant differences, but, in propranolol group, elongation of pain threshold time was observed in some subjects. During these processes, systemic blood pressure and heart rate showed no remarkable changes. Our results suggest that it is possible to achieve more prolonged analgesic effect by the Ca channel blockers.

Adult↗

[The treatment of neuralgiform facial pains with the combined therapy of transcutaneous electric nerve stimulation (TENS) and the iontophoresis of nonsteroidal antiphlogistics].

In a prospective study, 46 patients suffering from facial pain were treated by transcutaneous electrical nerve stimulation (TENS). In case of insufficient pain relief the combined use of TENS and iontophoresis of non-steroidal antiphlogistics was employed. Benzydamine was applied to the anode and diclofenac to the cathode instead of the contact gel, reducing average pain intensity to a marked 18%, compared to 81% to 63% by TENS only. Furthermore, the consumption of analgetics declined considerably with combined therapy. Severe side effects could not be registered. Therefore, this new combined therapy must be considered to be an alternative treatment before using systemic medication.

Adult↗

[Treatment of tinnitus by Neolidocatone administered by iontophoresis into the middle ear].

The authors describe a possible therapeutic approach mitigating tinnitus. It is not causal treatment but only symptomatic and extends the group of methods which influence tinnitus. The authors describe their own experience with iontophoresis of the middle ear with Neolidocatone-a derivate of Lidocaine which was done with a SANOMATIC apparatus, using galvanic current 1.5 mA. In one third of the patients it proved possible to mitigate the tinnitus permanently, in the remaining patients it persisted in the original intensity. The group of patients was heterogeneous from idiopathic tinnitus without impaired hearing, patients with otosclerosis, cervicocranial syndrome to those with Ménière's disease. The cause of tinnitus did not influence the therapeutic results.

Ear, Middle↗