The Detection of Small-Fiber Neuropathies in Burning Mouth Syndrome and Iatrogenic Lingual Nerve Injuries: Use of Quantitative Sensory Testing.

AIMS: To assess thermal pain perception in patients with burning mouth syndrome (BMS) and lingual nerve injury (LNI) by using a quantitative sensory testing (QST) protocol. METHODS: QST was used to assess cool, warm, cold pain, and heat pain thresholds in healthy control subjects (n = 17) and in patients with BMS (n = 22) and LNI (n = 47). Capsaicin (10 µg/mL) and ethyl chloride-evoked hypersensitivities at the anterior two-thirds of the tongue were measured using a visual analog scale. Data were analyzed using Microsoft Excel with descriptive statistics, scatter graphs, and two-tailed Student t tests with 95% confidence interval and 5% level of significance. RESULTS: Patients with BMS significantly reported the most pain at rest (P < .001) and capsaicin hypersensitivity (P < .01). Despite this increased sensitivity to capsaicin and significantly lower warm threshold than the control subjects (P < .05), these patients did not show heat pain hyperalgesia. There was increased sensitivity to ethyl chloride and cold pain hyperalgesia in patients with BMS (P < .05) compared with reduced or no sensation of cold or heat pain in patients with LNI. CONCLUSIONS: This study has demonstrated that the assessment of capsaicin and ethyl chloride-evoked sensitivities as well as the use of QST to assess thermosensitivity are useful approaches for detecting hyperalgesia or hypoalgesia to heat and cold in patients with BMS and LNI.

Ethyl chloride improves antiseptic effect of betadine skin preparation for office procedures.

To determine if ethyl chloride is an effective disinfectant alone or combined with povidone iodine in a clinical setting, 35 volunteers had different portions of their knees swabbed with sterile cotton-tip applicators after an area of skin was prepared with either ethyl chloride alone, povidone iodine alone, or povidone iodine followed by ethyl chloride. An area with no preparation at all served as the control. Specimens were then cultured on agar plates and bacterial growth assessed. When the data was categorized as colony forming units (CFUs) or no CFUs, both ethyl chloride and povidone iodine used alone had significantly fewer specimens with CFUs (p=0.001) than controls, but were not significantly different from each other (p=0.18). Additionally, the combination of povidone iodine followed by ethyl chloride spray had significantly fewer samples with CFUs than either product used alone (p=0.001). In addition to its local anesthetic properties, ethyl chloride may be an effective disinfectant alone and may improve skin disinfection when used with povidone iodine compared to povidone iodine alone.

Lignocaine is a better analgesic than either ethyl chloride or nitrous oxide for peripheral intravenous cannulation.

BACKGROUND: Peripheral intravenous (i.v.) cannulation is a painful, frequently performed ED procedure. It is common practice in other medical settings to offer analgesia prior to cannulation. OBJECTIVE: The present trial aims to reproduce in the ED studies that found a reduction in the pain of i.v. cannulation after intradermal lignocaine, ethyl chloride topical spray and entonox (50:50 oxygen : nitrous oxide). It also intends to determine which is analgesic most effective and explore the role of entonox for cannulation analgesia. METHODS: Three hundred subjects were randomized into four groups: i.v. cannula inserted with (i) no anaesthesia; (ii) entonox; (iii) ethyl chloride; and (iv) 0.1 mL intradermal 1% lignocaine. Pain was recorded on 100 mm visual analogue scales (VAS) after lignocaine injection or ethyl chloride spray and following i.v. cannulation. A clinically significant reduction in VAS pain score was determined to be 13 mm. RESULTS: Patients cannulated without analgesia reported the most pain. Those cannulated after lignocaine had the least pain (median VAS 20 mm, 95% CI 15-25, vs 1 mm 95% CI 0-6, P < or = 0.001). Ethyl chloride (VAS 11 mm, 95% CI 7-15, P = 0.003) and entonox (VAS 13 mm, 95% CI 8-18, P = 0.047) reduced i.v. cannulation pain but did not reach clinical significance. Neither pain from presenting symptoms (P = 0.3), nor size of cannula (P = 0.8) affected pain scores. VAS scores were independent of sex and age (P = 0.1). Cannulation success was not affected by either the choice of analgesia or cannulation site. CONCLUSIONS: The present trial confirms the findings of Harris and colleagues that lignocaine reduces the pain of cannulation in the ED. Lignocaine reduced the pain of i.v. cannulation more effectively than entonox or ethyl chloride.

A risk-benefit assessment of topical percutaneous local anaesthetics in children.

Since its introduction, eutectic lidocaine-prilocaine cream ('EMLA')1 has been found to be an effective topical anaesthetic agent, with a high degree of efficacy, particularly for venepuncture and venous cannulation, and an impressive tolerability profile. Reports of adverse effects are remarkable for their rarity. The only problems that are likely to be encountered are oral ingestion of the cream (which may lead to anaesthesia of the oropharynx and possible toxicity secondary to rapid absorption of local anaesthetic from oral mucous membranes) and methaemoglobinaemia following repeated applications in neonates and infants. Analysis of the risks and benefits associated with its use comes down heavily in favour of the preparation. More recently, a preparation of tetracaine (amethocaine) has been marketed as a gel. Its advantages are a faster onset, and longer duration, of action than 'EMLA'. Although less widely used, it too has an impressive tolerability record. Concerns over the potential for anaphylactic type reactions due to its ester structure have not been realised in clinical practice. Of the other available preparations, lidocaine (lignocaine), applied iontophoretically, is unlikely to become popular because of the complexity of administration. A paste made of tetracaine, epinephrine (adrenaline) and cocaine (TAC) appears to be a far more toxic preparation on theoretical grounds, and this has been borne out in clinical practice; it is not as well tolerated as 'EMLA' or tetracaine gel. Ethyl chloride, although not a local anaesthetic, can safely provide cutaneous analgesia in children in circumstances when it is impractical to wait for a local anaesthetic preparation to take effect.

Human epidermal Langerhans' cells are sensitive to rapid cooling by ethyl chloride.

Topical anesthesia with ethyl chloride spraying generates some remarkable reactive events in the human Langerhans' cell (LC) system. Many LC retract their dendrites and a considerable number move to the innermost layers of the epidermis within 15 minutes. This rapid motility supports the view that the interstices between cells in living epidermis are large. The LC cytomembrane is very susceptible to cold shock which causes the cytomembrane to superimpose upon itself forming abnormally shaped Birbeck granules. This process may consume too much of the cytomembrane to be compatible with cell survival.

Ethyl chloride: an ineffective bacteriostatic or cidal agent for arthrocentesis.

The local and general anesthetic properties of ethyl chloride have been well delineated. The purpose of this study was to determine if ethyl chloride, when used as a local anesthetic, had any bacteriostatic or cidal effects on the normal array of skin flora. Fifteen different aerobic bacteria or fungi were collected from pure cultures. A total of 30 specimens were sprayed; 2 specimens of each of the 15 bacteria were sprayed with ethyl chloride for both 5 and 10 seconds. These specimens then were restreaked once the ethyl chloride had evaporated, and were incubated for 24 hours. At 24 hours the cultures were checked and found to have no significant growth inhibitions. It is thus concluded that ethyl chloride alone does not have any bacteriostatic or cidal effects on these commonly found skin flora.

Effects of local anesthetics on phorbol ester-induced ornithine decarboxylase activity in mouse and human skin.

In preparation for experiments to determine the effects of various orally administered compounds on human skin ornithine decarboxylase (ODC) activity, it was observed that intradermal lidocaine hydrochloride inhibited 12-0-tetradecanoylphorbol-13-acetate (TPA)-induced ODC. Topically applied ethyl chloride had variable and unpredictable effects on ODC induction. Adequate local anesthesia can be obtained by using intradermal 1.0% procaine hydrochloride or normal saline; neither of these agents inhibited TPA induction of epidermal ODC activity in incubated human skin punch biopsies.

Pharmacology of chlorozotocin Nsc-178248), a new nitrosourea antitumor agent.

Structure-activity studies of nitrosourea pharmacology have resulted in the synthesis of a new water-soluble agent,chlorozotocin, which has significant antitumor activity against the L1210 leukemia system and produces only a minor degree of inhibition of mouse and human bone marrow DNA synthesis compared to BCNU. It is important to emphasize that the bone marrow sparing feature of chlorozotocin is relative and that if the drug is administered at lethal dose levels in mice, myelosuppression is observed. The potential importance of these studies is the identification of a new and active nitrosourea antiumor agent with modified bone marrow toxicity. If aminoglucose modification of nitrosourea bone marrow toxicity can be confirmed in man without significant loss of antitumor activity, the use of such a compound could facilitate treatment of patients with neoplastic disease who have pre-existing abnormal bone marrow function. It would also allow the more effective use of a nitrosourea agent in combination with anticancer agents possessing more potent myelosuppressive properties.

Carcinogenic potential of chlorinated ethylenes tentative molecular rules.

Chlorinated ethylenes are activated in mammalian metabolism to oxiranes. Only those with asymmetric chlorine substitution are mutagenic (trichloroethylene, vinylidence chloride and vinyl chloride) whilst the symetric molecules (tetrachloroethylene, cis- and trans-1.2-dichloroethylene) are inactive in this respect. Thus, stability of the oxirances (higher in the symmetric molecules, lower in the asymmetric ones) seems to be the important feature for the mutagenic, and possibly carcinogenic potential.

[Effect of Ethrel on the ultrastructure of some internal organs in rats. II. Kidneys]. / Wplyw Ethrelu na ultrastrukture niektórych narzadów miazszowych. II. Nerka

The ultrastructure of the epithelial cells of the proximal tubules of the kidneys was analyzed. Rats were treated with water solutions of Ethrel (AmChem 68-240) at 10, 100 and 200 mg per kg of body weight for seven days. An increase of thickness of the basic epithelial membranes and smoothing of the folds of the capsule at its base were observed in this study, as well as an increase of the number of the apical vesicles, lisosomes and microbodies. Lipid droplets appeared in the cytoplasm of the cells. These data proved the occurrence of some disturbances in the action of the cells studied. This was supported by the changes observed in the urine of the experimental animals. There were no toxic injuries to the epithelial cells of the proximal tubules of the kidneys which might be caused by Ethrel.