Transcutaneous Research Articles

Voluntary Modulation of Evoked Responses Generated by Epidural and Transcutaneous Spinal Stimulation in Humans with Spinal Cord Injury.

Transcutaneous (TSS) and epidural spinal stimulation (ESS) are electrophysiological techniques that have been used to investigate the interactions between exogenous electrical stimuli and spinal sensorimotor networks that integrate descending motor signals with afferent inputs from the periphery during motor tasks such as standing and stepping. Recently, pilot-phase clinical trials using ESS and TSS have demonstrated restoration of motor functions that were previously lost due to spinal cord injury (SCI). However, the spinal network interactions that occur in response to TSS or ESS pulses with spared descending connections across the site of SCI have yet to be characterized. Therefore, we examined the effects of delivering TSS or ESS pulses to the lumbosacral spinal cord in nine individuals with chronic SCI. During low-frequency stimulation, participants were instructed to relax or attempt maximum voluntary contraction to perform full leg flexion while supine. We observed similar lower-extremity neuromusculature activation during TSS and ESS when performed in the same participants while instructed to relax. Interestingly, when participants were instructed to attempt lower-extremity muscle contractions, both TSS- and ESS-evoked motor responses were significantly inhibited across all muscles. Participants with clinically complete SCI tested with ESS and participants with clinically incomplete SCI tested with TSS demonstrated greater ability to modulate evoked responses than participants with motor complete SCI tested with TSS, although this was not statistically significant due to a low number of subjects in each subgroup. These results suggest that descending commands combined with spinal stimulation may increase activity of inhibitory interneuronal circuitry within spinal sensorimotor networks in individuals with SCI, which may be relevant in the context of regaining functional motor outcomes.

A comparison of transcutaneous, transrectal, and hand-assisted laparoscopic abdominal ultrasonography in standing horses

Objective: The study was designed to compare three imaging modalities transcutaneous (TC), transrectal (TR), and hand-assisted laparoscopic ultrasonography (HALU) for evaluation of the abdominal viscera in the horse, and compared against the gold standard of actual measurements from each organ at post-mortem (PM) examination after 30 days of surgery Methods: Six non-pregnant mares were examined with TC, TR, and HALU. The TC and HALU were performed with the same probe so that a more accurate resolution comparison could be made. Measurements were taken from each of the different ultrasound images. Results: The measurements obtained with HALU were much closer to that obtained with the PM examination and more accurate than those obtained with TC and TR ultrasonography. The measurements obtained with TR are more accurate than those obtained with the TC. This illustrates the accuracy of HALU ultrasound compared to TC and TR ultrasonography. Conclusions and Clinical Relevance: It was obvious via subjective and objective results of image analysis that HALU was far more accurate and had better resolution than TC and TR. TC and TR ultrasonography would be recommended to be used as an initial screening method to evaluate the abdominal viscera, but if more details regarding organ structure are needed, HALU should be performed without reservation.

Transcutaneous Administration of Dengue Vaccines

In the present study, we evaluated the immunological responses induced by dengue vaccines under experimental conditions after delivery via a transcutaneous (TC) route. Vaccines against type 2 Dengue virus particles (DENV2 New Guinea C (NGC) strain) combined with enterotoxigenic Escherichia coli (ETEC) heat-labile toxin (LT) were administered to BALB/c mice in a three-dose immunization regimen via the TC route. As a control for the parenteral administration route, other mouse groups were immunized with the same vaccine formulation via the intradermic (ID) route. Our results showed that mice vaccinated either via the TC or ID routes developed similar protective immunity, as measured after lethal challenges with the DENV2 NGC strain. Notably, the vaccine delivered through the TC route induced lower serum antibody (IgG) responses with regard to ID-immunized mice, particularly after the third dose. The protective immunity elicited in TC-immunized mice was attributed to different antigen-specific antibody properties, such as epitope specificity and IgG subclass responses, and cellular immune responses, as determined by cytokine secretion profiles. Altogether, the results of the present study demonstrate the immunogenicity and protective properties of a dengue vaccine delivered through the TC route and offer perspectives for future clinical applications.

The Safety and Immunogenicity of GTU®MultiHIV DNA Vaccine Delivered by Transcutaneous and Intramuscular Injection With or Without Electroporation in HIV-1 Positive Subjects on Suppressive ART

Previous studies have shown targeting different tissues via the transcutaneous (TC) and intramuscular injection (IM) with or without electroporation (EP) has the potential to trigger immune responses to DNA vaccination. The CUTHIVTHER 001 Phase I/II randomized controlled clinical trial was designed to determine whether the mode of DNA vaccination delivery (TC+IM or EP+IM) could influence the quality and function of induced cellular immune responses compared to placebo, in an HIV positive clade B cohort on antiretroviral therapy (ART). The GTU®MultiHIV B DNA vaccine DNA vaccine encoded a MultiHIV B clade fusion protein to target the cellular response. Overall the vaccine and regimens were safe and well-tolerated. There were robust pre-vaccination IFN-γ responses with no measurable change following vaccination compared to placebo. However, modest intracellular cytokine staining (ICS) responses were seen in the TC+IM group. A high proportion of individuals demonstrated potent viral inhibition at baseline that was not improved by vaccination. These results show that HIV positive subjects with nadir CD4+ counts ≥250 on suppressive ART display potent levels of cellular immunity and viral inhibition, and that DNA vaccination alone is insufficient to improve such responses. These data suggest that more potent prime-boost vaccination strategies are likely needed to improve pre-existing responses in similar HIV-1 cohorts (This study has been registered at http://ClinicalTrials.gov under registration no. NCT02457689).

Combined skin and muscle vaccination differentially impact the quality of effector T cell functions: the CUTHIVAC-001 randomized trial

Targeting of different tissues via transcutaneous (TC), intradermal (ID) and intramuscular (IM) injection has the potential to tailor the immune response to DNA vaccination. In this Phase I randomised controlled clinical trial in HIV-1 negative volunteers we investigate whether the site and mode of DNA vaccination influences the quality of the cellular immune responses. We adopted a strategy of concurrent immunization combining IM injection with either ID or TC administration. As a third arm we assessed the response to IM injection administered with electroporation (EP). The DNA plasmid encoded a MultiHIV B clade fusion protein designed to induce cellular immunity. The vaccine and regimens were well tolerated. We observed differential shaping of vaccine induced virus-specific CD4 + and CD8 + cell-mediated immune responses. DNA given by IM + EP promoted strong IFN-γ responses and potent viral inhibition. ID + IM without EP resulted in a similar pattern of response but of lower magnitude. By contrast TC + IM (without EP) shifted responses towards a more Th-17 dominated phenotype, associated with mucosal and epidermal protection. Whilst preliminary, these results offer new perspectives for differential shaping of desired cellular immunity required to fight the wide range of complex and diverse infectious diseases and cancers.

Transcutaneous PCO2 Monitoring in Newborn Infants During General Anesthesia Is Technically Feasible.

Transcutaneous (TC) measurement of PCO2 (TC PCO2) is a well-established method to monitor assisted ventilation in neonatal intensive care, but its use in the operating room is limited, and the data regarding its performance during general anesthesia of the newborn are lacking. The aim of this study is to evaluate the performance of continuous TC PCO2 monitoring during general anesthesia in newborn infants. Infants (n = 25) with a gestational age of 23 to 41 weeks and a birth weight of 548 to 4114 g were prospectively enrolled. During general anesthesia and surgery, TC PCO2 was measured continuously and recorded at 1-minute intervals. Five-minute mean values were compared with simultaneously obtained blood gas (BG) analyses of PCO2. Only the first paired TC and BG samples were used in this analysis. We defined precision as 2.1 times the standard deviation of the difference of the 2 samples. P < .01 was considered statistically significant. We obtained samples from 25 infants. The difference between TC and BG was 0.3 ± 0.7 kPa (mean ± standard deviation) giving a precision of 1.47 kPa. Nineteen of twenty-five (76%) sample pairs displayed a difference of <1 kPa (99% confidence interval, 48%-92%, P = .016). The difference in paired samples was similar for different gestational and postnatal ages and did not appear to be affected by electrocautery. In this small study, we did not demonstrate that TC CO2 monitoring was accurate at P < .01. This partly reflects the small size of the study, resulting in wide 99% confidence bounds.

Carbon dioxide monitoring during laparoscopic-assisted bariatric surgery in severely obese patients: transcutaneous versus end-tidal techniques.

Various factors including severe obesity or increases in intra-abdominal pressure during laparoscopy can lead to inaccuracies in end-tidal carbon dioxide (PETCO2) monitoring. The current study prospectively compares ET and transcutaneous (TC) CO2 monitoring in severely obese adolescents and young adults during laparoscopic-assisted bariatric surgery. Carbon dioxide was measured with both ET and TC devices during insufflation and laparoscopic bariatric surgery. The differences between each measure (PETCO2 and TC-CO2) and the PaCO2 were compared using a non-paired t test, Fisher's exact test, and a Bland-Altman analysis. The study cohort included 25 adolescents with a mean body mass index of 50.2 kg/m2 undergoing laparoscopic bariatric surgery. There was no difference in the absolute difference between the TC-CO2 and PaCO2 (3.2±3.0 mmHg) and the absolute difference between the PETCO2 and PaCO2 (3.7±2.5 mmHg). The bias and precision were 0.3 and 4.3 mmHg for TC monitoring versus PaCO2 and 3.2 and 3.2 mmHg for ET monitoring versus PaCO2. In the young severely obese population both TC and PETCO2 monitoring can be used to effectively estimate PaCO2. The correlation of PaCO2 to TC-CO2 is good, and similar to the correlation of PaCO2 to PETCO2. In this population, both of these non-invasive measures of PaCO2 can be used to monitor ventilation and minimize arterial blood gas sampling.

Immunity against a Chlamydia infection and disease may be determined by a balance of IL‐17 signaling

Most vaccines developed against Chlamydia using animal models provide partial protection against a genital tract infection. However, protection against the oviduct pathology associated with infertility is highly variable and often has no defining immunological correlate. When comparing two adjuvants (CTA1-DD and a combination of Cholera toxin plus CpG-oligodeoxynucleotide-CT/CpG) combined with the chlamydial major outer membrane protein (MOMP) antigen and delivered via the intranasal (IN), sublingual (SL) or transcutaneous (TC) routes, we identified two vaccine groups with contrasting outcomes following infection. SL immunization with MOMP/CTA1-DD induced a 70% reduction in the incidence of oviduct pathology, without significantly altering the course of infection. Conversely, IN immunization with MOMP/CT/CpG prevented an ascending infection, but not the oviduct pathology. This anomaly presented a unique opportunity to study the mechanisms by which vaccines can prevent oviduct pathology, other than by controlling the infection. The IL-17 signaling in the oviducts was found to associate with both the enhancement of immunity to infection and the development of oviduct pathology. This conflicting role of IL-17 may provide some explanation for the discordance in protection between infection and disease and suggests that controlling immunopathology, as opposed to the rapid eradication of the infection, may be essential for an effective human chlamydial vaccine that prevents infertility.

Immunization with a MOMP-Based Vaccine Protects Mice against a Pulmonary Chlamydia Challenge and Identifies a Disconnection between Infection and Pathology

Chlamydia pneumoniae is responsible for up to 20% of community acquired pneumonia and can exacerbate chronic inflammatory diseases. As the majority of infections are either mild or asymptomatic, a vaccine is recognized to have the greatest potential to reduce infection and disease prevalence. Using the C. muridarum mouse model of infection, we immunized animals via the intranasal (IN), sublingual (SL) or transcutaneous (TC) routes, with recombinant chlamydial major outer membrane protein (MOMP) combined with adjuvants CTA1-DD or a combination of cholera toxin/CpG-oligodeoxynucleotide (CT/CpG). Vaccinated animals were challenged IN with C. muridarum and protection against infection and pathology was assessed. SL and TC immunization with MOMP and CT/CpG was the most protective, significantly reducing chlamydial burden in the lungs and preventing weight loss, which was similar to the protection induced by a previous live infection. Unlike a previous infection however, these vaccinations also provided almost complete protection against fibrotic scarring in the lungs. Protection against infection was associated with antigen-specific production of IFNγ, TNFα and IL-17 by splenocytes, however, protection against both infection and pathology required the induction of a similar pro-inflammatory response in the respiratory tract draining lymph nodes. Interestingly, we also identified two contrasting vaccinations capable of preventing infection or pathology individually. Animals IN immunized with MOMP and either adjuvant were protected from infection, but not the pathology. Conversely, animals TC immunized with MOMP and CTA1-DD were protected from pathology, even though the chlamydial burden in this group was equivalent to the unimmunized controls. This suggests that the development of pathology following an IN infection of vaccinated animals was independent of bacterial load and may have been driven instead by the adaptive immune response generated following immunization. This identifies a disconnection between the control of infection and the development of pathology, which may influence the design of future vaccines.

Transcutaneous DNA immunization following waxing-based hair depilation elicits both humoral and cellular immune responses

Previously, we showed that transcutaneous (TC) DNA immunization by applying plasmid DNA onto a mouse skin area wherein the hair follicles were induced into growth stage by plucking the hair using warm waxing induced strong and functional antigen-specific antibody responses. In the present study, using plasmids that encode β-galactosidase gene or ovalbumin (OVA) gene, we showed that this mode of TC DNA immunization not only induced specific antibody responses, but also induced antigen-specific cytotoxic T lymphocyte responses. In fact, TC DNA immunization using a plasmid that encodes OVA gene prevented the growth of OVA-expressing B16-OVA tumor cells in the immunized mice. Moreover, we provided additional evidence supporting that hair follicles are essential for this mode of TC DNA immunization.

Targeting of HIV-p24 particle-based vaccine into differential skin layers induces distinct arms of the immune responses

Skin routes of immunization such as subcutaneous (SC), intradermal (ID) and transcutaneous (TC) administration are utilized for vaccination against various pathogens, without understanding their potential impact on the outcome of immune responses. We demonstrated that SC immunization induced HIV-1 p24 specific IgG in absence of antigen-specific CD8 T cells, whereas the ID route induced both cellular and humoral responses. Interestingly, TC application through empty hair follicular ducts, targeting epidermal Langerhans Cells (LCs), induced major CD8 effector cells, in the absence of IgG. However, high levels of mucosal IgA, were localized in the stratified epithelium of the vagina after TC prime. We propose that re-directing the immune responses by targeting differential skin immunization routes, offers enormous potential for innovative vaccination strategies, especially against HIV.

Preferential Amplification of CD8 Effector-T Cells after Transcutaneous Application of an Inactivated Influenza Vaccine: A Randomized Phase I Trial

BackgroundCurrent conventional vaccination approaches do not induce potent CD8 T-cell responses for fighting mostly variable viral diseases such as influenza, avian influenza viruses or HIV. Following our recent study on vaccine penetration by targeting of vaccine to human hair follicular ducts surrounded by Langerhans cells, we tested in the first randomized Phase-Ia trial based on hair follicle penetration (namely transcutaneous route) the induction of virus-specific CD8 T cell responses.Methods and FindingsWe chose the inactivated influenza vaccine – a conventional licensed tetanus/influenza (TETAGRIP®) vaccine – to compare the safety and immunogenicity of transcutaneous (TC) versus IM immunization in two randomized controlled, multi-center Phase I trials including 24 healthy-volunteers and 12 HIV-infected patients. Vaccination was performed by application of inactivated influenza vaccine according to a standard protocol allowing the opening of the hair duct for the TC route or needle-injection for the IM route. We demonstrated that the safety of the two routes was similar. We showed the superiority of TC application, but not the IM route, to induce a significant increase in influenza-specific CD8 cytokine-producing cells in healthy-volunteers and in HIV-infected patients. However, these routes did not differ significantly for the induction of influenza-specific CD4 responses, and neutralizing antibodies were induced only by the IM route. The CD8 cell response is thus the major immune response observed after TC vaccination.ConclusionsThis Phase Ia clinical trial (Manon05) testing an anti-influenza vaccine demonstrated that vaccines designed for antibody induction by the IM route, generate vaccine-specific CD8 T cells when administered transcutaneously. These results underline the necessity of adapting vaccination strategies to control complex infectious diseases when CD8 cellular responses are crucial. Our work opens up a key area for the development of preventive and therapeutic vaccines for diseases in which CD8 cells play a crucial role.Trial RegistrationClinicaltrials.gov NCT00261001

Appropriateness of hospitalization for CAP-affected pediatric patients: report from a Southern Italy General Hospital

BackgroundCommunity-acquired pneumonia (CAP) is a common disease, responsible for significant healthcare expenditures, mostly because of hospitalization. Many practice guidelines on CAP have been developed, including admission criteria, but a few on appropriate hospitalization in children. The aim of this study was to evaluate appropriate hospital admission for CAP in a pediatric population.MethodsWe evaluated appropriate admission to a Pediatric Unit performing a retrospective analysis on CAP admitted pediatric patients from a Southern Italy area. Diagnosis was made based on clinical and radiological signs. Appropriate hospital admission was evaluated following clinical and non-clinical international criteria. Family ability to care children was assessed by evaluating social deprivation status.ResultsIn 2 winter seasons 120 pediatric patients aged 1-129 months were admitted because of CAP. Median age was 28.7 months. Raised body temperature was scored in 68.3% of patients, cough was present in 100% of cases, and abdominal pain was rarely evidenced. Inflammatory indices (ESR and CRP) were found elevated in 33.3% of cases. Anti-Mycoplasma pneumoniae antibodies were found positive in 20.4%. Trans-cutaneous (TC) SaO2 was found lower than 92% in 14.6%. Dyspnoea was present in 43.3%. Dehydration requiring i.v. fluid supplementation was scored in 13.3%. Evaluation of familial ability to care their children revealed that 76% of families (derived from socially depressed areas) were "at social risk", thus not able to appropriately care their children. Furthermore, analysis of CAP patients revealed that "at social risk" people accessed E.D. and were hospitalized more frequently than "not at risk" patients (odds ratio = 3.59, 95% CI: 1,15 to 11,12; p = 0.01), and that admitted "at social risk" people presented without clinical signs of severity (namely dyspnoea, and/or SaO2 ≤ 92%, and/or dehydration) more frequently than "not at risk" population (p = 0.005).ConclusionDyspnoea was found to be the main clinical criterion to define an appropriate children admission for CAP. Other more objective evaluation (i.e. oxygen pulse oxymetry) could underestimate the necessity of hospitalization as patients discomfort could be more severe then indicated by TC SaO2. Furthermore, family inability to children care represents the main criterion for hospital admission in our geographic area. It reflects social deprivation status and it should be strongly considered in deciding for children hospital admission.

Transcutaneous Anti-Influenza Vaccination Promotes Both CD4 and CD8 T Cell Immune Responses in Humans

Induction of T cell responses has become one of the major goals in therapeutic vaccination against viral diseases and cancer. The use of the skin as target organ for vaccine has been spurred by recent implication of epithelial dendritic cells in CD8 cell cross-priming and suggests that vaccination via the transcutaneous (TC) route may be relevant in the induction of cellular immune responses. We have previously shown that TC application of nanoparticles, on human skin explants, allows targeting of epidermal dendritic cells, possibly via hair follicles. In this study, we have investigated cellular immune responses against an influenza protein-based vaccine by TC vaccination, compared with i.m. vaccination in humans. In this study on 11 healthy volunteers, we found that a newly developed protocol based on cyanoacrylate skin surface stripping induced a significant increase in IFN-gamma-producing T cells specific for influenza vaccine by ELISPOT assays. Interestingly, TC vaccination induced both effector CD4 and CD8 T cell responses, whereas i.m. injection induced strong effector CD4 in the absence of CD8 T cells, as assessed by intracellular cytokine staining and tetramer analyses. This study proposes new perspectives for the development of vaccination strategies that trigger T cell immune responses in humans.

Effect of adjuvants and route of immunizations on the immune response to recombinant plague antigens

In this study, we compare four different adjuvants, LT(R192G), CpG ODN, MPL ®TDM, and alum, for their ability to affect the magnitude, distribution, and duration of antibody responses against F1-V, the lead-candidate antigen for the next generation vaccine against plague, in a murine model. In addition, three different routes of immunization—intranasal (IN), transcutaneous (TC), and subcutaneous (SC) were compared with each adjuvant. Since aerosol exposure to biological warfare agents is of primary concern, both serum and bronchioalveolar lavage (BAL) were analyzed for antigen-specific antibody responses. The most significant findings of the study reported here are that (1) the adjuvant influences the Type 1/Type 2 balance of the antibody response in both the serum and BAL, (2) mucosal immunization is not necessary to obtain F1-V-specific BAL responses, (3) non-traditional adjuvants such as LT(R192G) work when delivered subcutaneously, (4) the route of immunization affects the magnitude of the immune response, and (5) F1-V is highly immunogenic by some routes even in the absence of an exogenously applied adjuvant. These studies provide important insights into the influence of different classes of adjuvants on the immune outcome in biodefense vaccines and for development of new-generation vaccines against other pathogens as well.

An Evaluation of Acid–Base Changes Following Aortic Cross-Clamping Using Transcutaneous Carbon Dioxide Monitoring

To investigate the cause of acidosis following release of an aortic cross-clamp, we measured tissue PCO2 using a transcutaneous (TC) CO2 monitor placed below the level of the cross-clamp in 10 patients undergoing aortic arch surgery. Following placement of the aortic cross-clamp, the TC CO2 value from the lower extremity increased from 41 +/- 4 to 92 +/- 41, whereas there was no change in the TC CO2 value from the upper extremity. With release of the cross-clamp, end-tidal CO2 increased by 6.2 +/- 1.9 mmHg, the upper TC CO2 increased by 8.4 +/- 4.8 mmHg, and the lower extremity TC CO2 value returned to baseline. During cross-clamping, there was an increase in the base deficit of 4.3 +/- 2.9 when comparing the baseline arterial blood gas value with the one obtained after cross-clamp release (p = 0.0004). These data demonstrate that the acidosis occurring during aortic cross-clamping is a mixed metabolic and hypercarbic acidosis. Appropriate treatment includes the provision of adequate minute ventilation to ensure CO2 removal and the use of sodium bicarbonate based on the degree of metabolic acidosis demonstrated by arterial blood gas analysis.

Anesthetic Care During Modified Fontan Procedure Without Cardiopulmonary Bypass

The purpose of this study was to report the anesthetic care of patients during performance of a Fontan procedure without cardiopulmonary bypass (CPB). Retrospective chart review. Operating room of a university hospital. Seven pediatric-patients undergoing inferior vena cava (IVC)-to-pulmonary artery (PA) anastomosis for completion of the Fontan procedure. Charts were reviewed for anesthetic technique, hemodynamic and ventilatory changes occurring during the procedure, and anesthetic interventions that were provided. The off-bypass Fontan procedure was attempted in 7 patients (age: 26 months-7 years, weight: 13 to 28 kg). Exposure of the PA was not feasible in 1 patient because of a markedly enlarged right atrium. In the remaining 6 patients, before cross-clamping of the PA to allow for the proximal anastomosis between the PA and the conduit, alkalosis (pH > or =7.5) was maintained by the administration of sodium bicarbonate. After PA cross-clamping, fluid administration was necessary in 5 patients and dopamine (3-7 microg/kg/min) was necessary in 4 patients. The minute ventilation was increased by 18 +/- 7% to maintain baseline PaCO2 values. Before the placement of the PA cross-clamp, the end-tidal PaCO2 difference was 7 +/- 4 mmHg and the transcutaneous (TC)-PaCO2 difference was 3 +/- 2 mmHg. The end-tidal PaCO2 difference increased to 14 +/- 6 mmHg during cross-clamping of the PA, whereas no change was noted in the TC-PaCO2 difference. Once the proximal anastomosis was completed, a bridge was placed to redirect blood from the IVC to the right atrium while the IVC was clamped and attached to the distal end of the conduit. After placement of the distal end of the bridge into the IVC, fluid administration to maintain the blood pressure was necessary in 3 patients. In 1 patient, 20 minutes after placement of the bridge, the authors noted a progressive increase in the central venous pressure reading measured from the left femoral vein and the need for the administration of volume to maintain the mean arterial pressure. Examination of the bridge revealed occlusion with thrombus despite an activated coagulation time value of 250 to 300 seconds. The tracheas of 3 of the 6 patients were extubated in the operating room, whereas the other 3 were extubated in the pediatric intensive care unit within 4 hours of completion of the procedure. The 1 patient who required the use of CPB required reintubation and had a protracted intensive care unit course. The other 6 patients were discharged home on postoperative days 7 to 12. With alteration of the anesthetic technique, the Fontan procedure can be performed in selected patients without the need for CPB.

Noninvasive Monitoring of Carbon Dioxide in Infants and Children With Congenital Heart Disease: End-Tidal Versus Transcutaneous Techniques

End-tidal CO2 (ET(CO2)) monitoring and transcutaneous (TC) CO2 monitoring were prospectively compared in 53 patients, 1 month to 16 years of age, with congenital heart disease (CHD). There were 32 patients with cyanotic CHD and 21 with acyanotic CHD. The TC-Pa(CO2) difference was 2 +/- 1 mm Hg and the ET-Pa(CO2) difference was 5 +/- 3 mm Hg (P < .0001). The TC-Pa(CO2) difference was < or = 2 mm Hg in 30 of 53 patients and < or = 5 mm Hg in 53 of 53 patients. The ET-Pa(CO2) difference was < or = 2 mm Hg in 9 of 53 patients and < or = 5 mm Hg in 30 of 53 patients (P < .001). No variation in the TC-Pa(CO2) difference was noted based on the type of CHD (acyanotic vs cyanotic) or age. The ET-Pa(CO2) difference was greater in patients with cyanotic versus acyanotic CHD (7 +/- 3 mm Hg vs 4 +/- 2 mm Hg, P < .0001) and in patients < or = 1 year of age versus patients > or = 1 year of age (6 +/- 3 mm Hg vs 4 +/- 2, P = .008). In infants and children with CHD, TC monitoring provides a more accurate estimation of Pa(CO2) than ET monitoring.

Immunisation against plague by transcutaneous and intradermal application of subunit antigens

We have investigated immunological responses in BALB/c mice following transcutaneous (TC) delivery of fraction 1 (F1) and V subunits from Yersinia pestis in conjunction with an enterotoxin-derived adjuvant (cholera toxin, CT). It was found that two or more TC applications of F1 and V subunits (admixed with cholera toxin) served to elicit significant levels of anti-F1 and V antibodies in the serum of immunised mice. IL-6 secretion from cultured splenocytes derived from immunised mice indicated that a single TC application of F1 and V subunits (admixed with cholera toxin) conferred a cell-mediated response. As compared with intranasal or direct intradermal injection of F1 and V, the numbers of F1/V-specific antibody-forming cells in the spleens of animals immunised by TC application of F1 and V (admixed with CT) was relatively low. It was noted that TC application of F1 and V admixed with CT was very effective for priming responses that were boosted by intranasal or intradermal routes. Similarly, it was found that TC application of F1 and V admixed with CT could be used to efficiently boost pre-existing responses engendered by intradermal injection or intranasal instillation of F1 and V. In order to assess if TC application of F1 and V admixed with CT could protect experimental animals from plague, immunised mice were injected with a virulent strain of Y. pestis. It was found that two TC applications of F1 and V admixed with CT conferred only limited protection against 10 2 MLDs. However, three TC applications of F1 and V admixed with CT conferred solid protection against 10 2 MLDs. Hence we have shown, for the first time, that TC application of F1 and V admixed with CT can protect animals against challenge with a virulent strain of plague causing bacteria. These data suggest that transcutaneous immunisation may be a simple and non-invasive method for immunising individuals against plague.

Changes in transcutaneous carbon dioxide, oxygen saturation, and respiratory rate after interscalene block.

We used transcutaneous (TC) carbon dioxide (CO2) monitoring to prospectively evaluate changes in respiratory status after interscalene anesthesia in 45 adults (40 successful and 5 unsuccessful blocks). TC-CO2 oxygen saturation and respiratory rate were recorded every minute for 5 minutes before block and every 2 minutes for a total of 30 minutes (15 data sets) after injection of the local anesthetic solution. After successful block, TC-CO2 increased from 41 +/- 5 mm Hg to a maximum value of 44 +/- 6 mm Hg (P < 0.0001) and the respiratory rate increased from 14 +/- 2 breaths/min to a maximum of 20 +/- 4 breaths/min (P < 0.001). The increase in TC-CO2 was > or = 5 mm Hg in 11 patients and > or = 10 mm Hg in 4 patients, with a maximum increase of 12 mm Hg. Of the 600 TC-CO2 data points recorded (15 each from the 40 patients with a successful block), 62 (10.3%) showed a TC-CO2 value of 50 mm Hg or greater, with a maximum value of 57 mm Hg. No significant change in TC-CO2 or respiratory rate was seen in the five patients with unsuccessful block. After interscalene blockade, we found an increase in respiratory rate and hypercarbia that resulted in no clinically significant effect.