Benzyl alcohol attenuates the pain of lidocaine injections and prolongs anesthesia.

BACKGROUND: Benzyl alcohol is reported to be painless on injection and to provide limited dermal anesthesia. Benzyl alcohol has also been recommended as an adjuvant to lidocaine to reduce lidocaine's injection pain. There is insufficient data on pain of injection and duration of anesthesia for lidocaine containing benzyl alcohol. OBJECTIVE: We conducted a randomized, placebo-controlled, double-blinded comparison of intradermal 1% lidocaine with 0.86% benzyl alcohol and plain 1% lidocaine for pain of injection and duration of anesthesia. METHODS: Twenty subjects received the above two agents plus normal saline with and without 0.9% benzyl alcohol, with all solutions adjusted to 375 +/- 13 mosm/L. RESULTS: Lidocaine containing benzyl alcohol was 27% less painful upon injection and provided anesthesia 29% longer than plain lidocaine. CONCLUSION: Benzyl alcohol is itself an effective anesthetic and can reduce the pain of injection for lidocaine without adversely affecting its anesthetic properties.

Pain of injection and duration of anesthesia for intradermal infiltration of lidocaine, bupivacaine, and etidocaine.

BACKGROUND: Bupivacaine and etidocaine are local anesthetics said to be long acting based on nerve block data. There are insufficient data on pain of infiltration and duration of anesthesia when either is used for dermal infiltration to assess suitability for skin surgery. OBJECTIVE: We conducted a randomized, placebo-controlled, double-blinded comparison of intradermal 1% etidocaine, 0.5% bupivacaine, and 2% lidocaine for pain of injection and duration of anesthesia. METHODS: Twenty subjects received the above three agents plus normal saline, each with and without epinephrine 1:200,000, with all solutions adjusted to pH 5.95 +/- 0.15. RESULTS: Lidocaine hurt least and etidocaine hurt most. Adrenalized solutions were more painful than plain. For plain solutions bupivacaine lasted longest and lidocaine lasted shortest by far. For adrenalized solutions bupivacaine lasted 27% longer than lidocaine and 45% longer than etidocaine. CONCLUSION: Where epinephrine is contraindicated and long anesthesia matters, use plain bupivacaine. When epinephrine can be used, lidocaine lasts almost as long as bupivacaine and hurts less.

Dilated pore nevus. A histologic variant of nevus comedonicus.

Histology of a nevus comedonicus showed aggregates of dilated follicular cysts reminiscent of dilated pore of Winer. This finding has not been previously reported. We propose the term dilated pore nevus for this lesion, which we conceive to be a histologic variant of nevus comedonicus, similar to porokeratotic eccrine ostial and dermal duct nevus.

Surgical anatomy of the nail unit.

A gross anatomic exploration of the nail unit was performed. The characteristic gross components of the nail unit and its relationship to the digital anatomy are described and presented in detail. Each segment of the nail unit is illustrated both photographically and with artistic illustration. It is our intention that through a simple gross dissection the nail structural unit may be better understood.

Daily observations during healing of a full-thickness human surgical wound by second intention.

After his preauricular basal cell carcinoma had been excised by Mohs micrographic surgery, a patient took daily photographs of his 6 x 3-cm full-thickness wound as it healed by second intention over the next 44 days. Wound contraction produced a linear decrease in wound area between postoperative days 3 and 40 that accounted for 57% of the area of the original wound. The remainder of the wound was resurfaced by new epithelium, beginning on day 16. Few comparable reports address the contributions of contraction and re-epithelialization in large full-thickness human wounds.

Squamous cell carcinoma presenting as subcutaneous nodules.

Four patients with squamous cell carcinomas (SCCs) presenting as subcutaneous nodules of the head were referred for Mohs micrographic surgery. In each case initial histologic sections showed no connection between the tumor and epidermis, raising the possibility that each was a metastasis from an occult SCC. Careful searches for occult SCCs were unrevealing. Subsequent step sections through the entire tumors revealed narrow connections to the overlying epidermis in three of the four cases.

Squamous cell carcinoma of the sole in a patient with chronic graft-vs-host disease.

Chronic graft-vs-host disease (GvHD) is a common, severe complication of bone marrow transplantation that often results in sclerodermoid skin changes with chronic and recurrent skin ulceration. We describe a case of cutaneous squamous cell carcinoma presenting as an ulcer on the sole of a 20-year-old woman with chronic GvHD. Although such an association has not been previously described, we discuss why features of chronic GvHD could be expected to place affected patients at increased risk for cutaneous squamous cell carcinoma.

Electric shock does not save snakebitten rats.

A team of missionary doctors from Ecuador recently described striking success in the treatment of venomous snakebites with a series of brief, high-voltage, low-current electric shocks applied to the bit site. We designed a randomized, controlled, blinded test of their methods in laboratory rats. Venom of the fer-de-lance, Bothrops atrox, was injected subcutaneously into rats in a series of increasing doses. Half of each dose group then was shocked with a device used by the Ecuadoran group. Envenomated animals developed hemorrhagic ulcers at the injection sites, the size of which was strongly related to venom dose. Electric shock did not influence the development of morbidity or the eventual ulcer size in sublethally envenomated animals, nor did shocks reduce mortality in lethally envenomated animals. We conclude that shocks are without effect on snakebitten rats, and we discuss implications of our findings for the treatment of snakebitten human beings.

Behavioral treatment of the traumatically brain-injured: a case study.

The present case illustrates the application of behavioral modification methodology with a traumatically brain-injured adult. Such a treatment regime utilizing a report-card system and a response-cost procedure was implemented to decrease behaviors of using foul language and biting staff members. Dramatic improvement was demonstrated.

Partial molting synchrony in the giant Malaysian prawn,Macrobrachium rosenbergii: A chemical communication hypothesis.

Groups of 50 juvenile specimens ofM. rosenbergii were observed daily for the occurrence of molting for periods up to 50 days. Each animal in a group was physically isolated from the others in one of 50 chambers assembled in a flat chamber array that was immersed in a recirculated bath of fresh water (28 ° C). While an average of 6.4% of the animals molted each day in each of three separate trials, molting occurred in significantly nonrandom peaks and valleys. There was no evidence that peaks in molting frequency occurred at regular intervals, nor were animals of the same size molting synchronously, although weight and molting frequency were significantly correlated. Based on intervals between molts predicted from animal weights, animals molting during a peak molted sooner than animals molting with few others. Molting frequency in a group of animals tended to rise until water was changed, at which time molting frequency dropped significantly. Within each array of animal chambers, animals molted in significant spatial aggregations that coincided with the measured pattern of water flow among chambers in the array. Those spatial aggregations were most pronounced during peaks in molting frequency. These results suggest that some waterborne stimulus, perhaps released by molting animals, is responsible for partial molting synchrony in groups ofM. rosenbergii. The potential advantage of molting synchrony is discussed in connection with the behavioral ecology ofM. rosenbergii.

Proline inhibition of a sea anemone alarm pheromone response.

1. L-proline, by itself or in animal tissue extracts, inhibits the response of the sea anemone Anthopleura elegantissima to the alarm phermone, anthopeurine. 2. The effect of proline is mediated by a receptor that is specific for the structure and configuration of the part of the L-proline molecule containing the carboxyl and imino groups. 3. Proline inhibition is competitive, in the sense that the effects of a given proline concentration can be overridden by an increase in anthopeurine concentration. 4. The magnitude of proline inhibition increases with proline concentration and decreases as the duration of exposure to proline increases. 5. Neither the final conducting system mediating the alarm response nor the responding muscles are inhbited by proline. Inhibition presumably occurs at or soon after the level of anthopleurine receptors. 6. Proline inhibition may resolve the potential conflict between Anthopleura's mutually exclusive feeding and alarm pheromone responses.

Anthopleurine: a sea anemone alarm pheromone.

The sea anemone Anthopleura elegantissima responds with characteristic contraction to a pheromone released by wounded conspecifics. The alarm pheromone was isolated by ion-exchange chromatography and identified by chemical and spectroscopic methods as the quaternary ammonium ion (3-carboxy-2, 3-dihydroxy-N, N, N-trimethyl)-1-propanaminium. Median effective concentration of the crystalline pheromone is 3.5 X 10-minus 10 mole per liter of seawater.