Phosphodiesterase-5 inhibitors help climbers to achieve new heights.
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Altitude Sickness↗
Biomedical subjects
Chris Anderson
Publications and source records attributed to Chris Anderson.
Interferon-gamma secreted from peripheral blood mononuclear cells as a possible diagnostic marker for allergic contact dermatitis to gold.
10% of patch-tested patients have a positive reaction to gold. Most lack clinical symptoms, but allergic contact dermatitis (ACD) to gold is increasing. In this study, 77 dermatological outpatients were divided into 3 groups depending on epicutaneous patch test outcomes: a group positive to gold (EPI+), a group negative to gold (EPI-), and a group with irritant reactions to gold (EPI-IR). Lymphocytes were stimulated in vitro with gold sodium thiosulfate. Proliferation was assessed using the lymphocyte transformation test (LTT), and cytokine secretion was assessed using a multibead array (Luminex; Linco Research Inc., St. Charles, MO, USA), in order to evaluate whether an in vitro method with high diagnostic accuracy could be devised. The EPI+ group showed a significantly increased secretion of interferon (IFN)-gamma, interleukin (IL)-2, and IL-13 and also showed a significantly higher stimulation indexes for LTT, compared to the other 2 subject groups. Sensitivity and specificity were calculated for all methods individually and combined, but IFN-gamma assessment alone was the most accurate method for identifying ACD to gold, with sensitivity and specificity of 81.8% and 82.1%, respectively. This method also identified 87.5% of the EPI-IR subjects as non-allergic. Therefore, assessment of secretion of IFN-gamma should be a valuable complement to patch test for diagnosing gold allergy.
Adult↗
Endoscopic extraperitoneal radical prostatectomy in patients with prostate cancer and previous laparoscopic inguinal mesh placement for hernia repair.
INTRODUCTION: Since laparoscopic inguinal hernia repair has become a frequently performed surgical procedure, it is inevitable that patients who have been candidates for laparoscopic radical prostatectomy (LRP) may have had such prior intervention. The inguinal hernia repair might take the form of either total extraperitoneal hernioplasty (TEP) or transabdominal extraperitoneal hernioplasty (TAPP), with mesh placement. The objective was to show that performing endoscopic extraperitoneal radical prostatectomy (EERPE) in such patients was safe and feasible, and also to suggest modifications of the technique to facilitate the surgery. PATIENTS AND METHODS: There were no specific selection criteria and patients with prior mesh placements were encountered during the management of all consecutive patients undergoing EERPE. Modifications in the port placements were made to accommodate for previous mesh placements on the right and left side. The area of prior mesh placement was excluded from the dissection when creating the extraperitoneal space. The operation was performed, thereafter, using the standard EERPE method. RESULTS: Out of a total of 750 patients operated on with EERPE, 14 had prior TEP or TAPP with mesh placement. In both groups there were no differences found in the mean operative time. There were no major complications or reinterventions in patients with prior mesh placement. In each group (i.e. TEP and TAPP), a small bladder injury was diagnosed and managed intraoperatively with no further complication. One vascular injury to the inferior epigastric vessels was managed intraoperatively without significant blood loss. None of the 14 patients required blood transfusion. The mean catheterization time was 6.9 days. CONCLUSION: Although certain problems were presented by previous TEP/TAPP, it is nevertheless feasible to perform EERPE. By adapting port placements and surgical techniques the operation can be performed safely and with a good operative outcome.
Aged↗
Modular surgical training for endoscopic extraperitoneal radical prostatectomy.
OBJECTIVE: To develop a modular training scheme which enabled the use of individual steps of laparoscopic radical prostatectomy (RP) for teaching and training surgeons with varied experience, including residents with no experience in open RP, as in extending laparoscopic surgery to more complex operations like RP, the proper training of urologists is crucial. SUBJECTS AND METHODS: The technique of endoscopic extraperitoneal RP (EERP) was divided into 12 individual steps of differing complexity. The levels of difficulty were called "modules" and graded according to their requisite skills from module 1 (lowest level of difficulty) to module 5 (highest level). Based on this modular system we established a training programme whereby the trainee learns the procedure in a mentor-initiated schedule. During each training operation the trainee only performs the modules (steps) of the operation, which correspond with his or her actual skill level. The mentor performs all the other steps, with the trainee assisting. Four trainees with different surgical experience participated in the study. RESULTS: After a phase of assisting and camera holding during EERP, the trainees entered the modular training programme and required 32-43 procedures until they were considered to be competent. An analysis of the first 25-50 procedures done independently by the trainee showed mean operative times of 176-193 min and a transfusion rate of 1.3%. Complications during and after EERP requiring re-intervention were one each of recto-urethral fistula, haemorrhage, symptomatic lymphocele and anastomotic leak. The positive margin rate for pT2 disease was 12.2% and for pT3 tumours 37%. CONCLUSION: The modular concept for teaching EERP is an attractive concept, which overcomes many of the problems involved in complex laparoscopic procedures. Based on a highly standardized technique, this concept offers a short learning curve; it enables training on different sites in cooperation with a high-volume centre, and it makes it possible to start with this complex procedure as a beginner or with no experience in open RP.
Aged↗
A microdialysis technique for routine measurement of macromolecules in the injured human brain.
OBJECTIVE: To evaluate a new intracerebral microdialysis catheter with a high-cutoff membrane and its potential for the study of macromolecules in the human brain. METHODS: Paired intracerebral microdialysis catheters were inserted in 10 patients who became comatose after subarachnoid hemorrhage or traumatic brain injury and were then treated in our neurosurgical unit. The only differences from the routine use of microdialysis in our clinic were the length (20 mm) and cutoff properties of the catheter membranes (100 kD) and the perfusion fluids used (standard perfusion fluid, 3.5% albumin, or Ringer-dextran 60). Samples were weighed (for net fluid fluxes) and analyzed at bedside (for routine metabolites) and later in the laboratory (for total protein and interleukin-6). The in vitro recovery of glucose, glutamate, and glycerol were also investigated under different conditions. RESULTS: Even brief perfusion with standard perfusion fluid resulted in a significant loss of volume from the microdialysis system. For albumin and Ringer-dextran 60 fluid, recovery was comparable to standard settings. Interleukin-6 (highest value close to 25,000 pg/ml) was sampled from all catheters, and total protein was analyzed from catheters perfused with Ringer-dextran 60 (average concentration, 234 mug protein/ml). There were detectable patterns of variations in the concentration of interleukin-6, seemingly related to concomitant variations in intracerebral conditions. In the present study, no direct comparison was made with the standard CMA 70 catheter (CMA Microdialysis, Stockholm, Sweden), but in vivo, the measured mean concentrations of glucose, glycerol, lactate, and pyruvate were comparable to those previously reported from standard catheters. In vitro, the recovery of metabolites was better when using Ringer-dextran 60 compared with albumin. CONCLUSION: Microdialysis catheters with high-cutoff membranes can be used in routine clinical practice, allowing for sampling and analysis of cytokines and other macromolecules.
Brain Chemistry↗
A prospective study of the use of cryosurgery for the treatment of actinic keratoses.
BACKGROUND: Actinic keratoses are the most common actinic lesions on Caucasian skin. Cryosurgery with liquid nitrogen is commonly used to treat actinic keratoses, but there have been few studies examining the true rate of cure in everyday dermatologic practice. AIM: To determine prospectively the true efficacy of cryosurgery as a treatment for actinic keratoses in everyday dermatologic practice. METHODS: A prospective, multicentered study (a subsidiary study of a photodynamic therapy trial) was performed. Patients with untreated actinic keratoses greater than 5 mm in diameter on the face and scalp were recruited. Eligible lesions received a single freeze-thaw cycle with liquid nitrogen given via a spray device and were reviewed 3 months thereafter. Each center used their preferred freeze time. The only treatment criterion was complete freezing of actinic keratoses and a 1-mm rim of normal skin. Treated lesions were assessed as complete response or noncomplete response. The influence of the duration of freeze, cosmetic outcomes, and adverse events were examined. RESULTS: Ninety adult patients from the community with 421 eligible actinic keratoses were recruited. The overall individual complete response rate was 67.2%[SEM = +/-3.5%; 95% confidence interval (CI) = 60.4-74.1%]. Complete response was 39% for freeze times of less than 5 s, 69% for freeze times greater than 5 s, and 83% for freeze times greater than 20 s. Cosmetic outcomes were good to excellent in 94% of complete response lesions. The main adverse events were pain, stinging, and burning during treatment, and hypopigmentation after healing. CONCLUSIONS: Cryosurgery is an effective treatment for actinic keratoses. The true complete response rate is significantly lower than that previously reported. The freeze duration influences successful treatment. Adverse events are mild and well tolerated.
Adult↗
Malassezia yeasts in the pathogenesis of atopic dermatitis.
Atopic dermatitis is a common skin condition, the aetiology of which is multifactorial, involving genetic, immunological and environmental factors. In recent years, it has been suggested that various microbial organisms may also be involved in the pathogenesis of the disease. Yeasts belonging to the Malassezia genus have received particular attention. These yeasts, known to be a part of the normal skin flora, have been shown to be capable of inducing immunoglobulin (Ig)E-mediated and T-cell mediated immune responses postulated to contribute to chronic inflammation in the skin, particularly in the head and neck region, where colonization with Malassezia is the greatest. Considerable evidence now exists to support this idea, raising the possibility that specific antifungal therapy may be a useful treatment measure in some atopic patients who have a head and neck pattern of dermatitis.
Antifungal Agents↗
Phototesting with a divergent UVB beam in the investigation of anti-inflammatory effects of topically applied substances.
BACKGROUND: Phototesting based on a single exposure to a divergent ultraviolet B (UVB) beam with radially decreasing UVB doses can be used to determine an individual's minimal erythema dose (MED). Laser Doppler perfusion imaging (LDPI) data can be combined with dosimetry data to produce objective dose-response plots in addition to the MED. The aim of this study was to investigate whether the divergent beam protocol could be used to demonstrate and quantify the anti-inflammatory effects of clobetasol diproprionate (Dermovate), pharmaceutical-grade acetone and a gel vehicle, applied after skin provocation by UVB. METHOD: Sixteen Caucasian subjects were illuminated with the divergent beam on three areas close together on the left side of their upper backs. Two of the provoked areas on each subject were treated with acetone, gel vehicle or Dermovate, and one area was left untreated as a control. Skin blood perfusion was assessed 6 and 24 h after UVB illumination using LDPI. The reaction diameter, the mean perfusion, and the average dose-response plots for each group and treatment were extracted from the LDPI data. RESULTS: Application of the topical steroid clobetasol diproprionate after UVB provocation markedly decreased the inflammatory response. Acetone and the gel vehicle also showed mild anti-inflammmatory effects in two of the parameters but not for the mean perfusion response. The mean diameter differences between controls and treated reactions had predominantly positive 99% confidence intervals. Analysis of the dose-response data at doses higher than the MED showed a linear relationship (0.89<or=R2<or=0.98) for all reactions but with lower gradients in treated reactions, mostly marked for clobetasol diproprionate. CONCLUSIONS: The divergent beam protocol can be used to demonstrate and quantify the effects of topical agents on the UVB reaction, in terms of reaction diameter, mean perfusion and changes in dose-response characteristics. The dose-response approach seems to be applicable even in diagnostic testing of an individual patient's response to UVB.
Acetone↗
A double-blind study comparing the effect of glycerin and urea on dry, eczematous skin in atopic patients.
Moisturizing creams have beneficial effects in the treatment of dry, scaly skin, but they may induce adverse skin reactions. In a randomized double-blind study, 197 patients with atopic dermatitis were treated with one of the following: a new moisturizing cream with 20% glycerin, its cream base without glycerin as placebo, or a cream with 4% urea and 4% sodium chloride. The patients were asked to apply the cream at least once daily for 30 days. Adverse skin reactions and changes in skin dryness were assessed by the patient and a dermatologist. Adverse skin reactions such as smarting (a sharp local superficial sensation) were felt significantly less among patients using the 20% glycerin cream compared with the urea-saline cream, because 10% of the patients judged the smarting as severe or moderate when using glycerin cream, whereas 24% did so using urea-saline cream (p < 0.0006). No differences were found regarding skin reactions such as stinging, itching and dryness/irritation. The study showed equal effects on skin dryness as judged by the patients and the dermatologist. In conclusion, a glycerin containing cream appears to be a suitable alternative to urea/sodium chloride in the treatment of atopic dry skin.
Administration, Topical↗
Is vascular reactivity in skin predictable?
BACKGROUND/AIMS: Cutaneous microdialysis can be used to follow the pharmacology and metabolism of an inflammatory reaction. It is assumed that an equilibration period compensates for the trauma of catheter insertion. METHODS: In the present paper, the vascular reactivity of the skin to histamine was tested using assessment by laser Doppler perfusion imaging. In a group of six subjects, the provocation was preceded by insertion of a microdialysis catheter. In a second control group, histamine provocation alone was performed (six subjects). RESULTS: The vascular response to histamine was greater in the microdialysis catheter group than the control group. The histamine provocation caused a greater response than catheter insertion. Further, there was a correlation between the response to catheter insertion and the histamine provocation. CONCLUSION: It appears that the insertion and/or presence of a microdialysis catheter increases vascular reactivity to subsequent provocation. The response to catheter insertion may predict skin reactivity in general in the individual subject.
Journal Article↗