Pigmented melanocytes are protected against ultraviolet-A-induced membrane damage

The dominant skin pigment melanin is believed to protect human skin against several harmful effects of ultraviolet radiation. It is not clear, however, how melanin located inside melanin-producing melanocytes modulates the effect of ultraviolet radiation on melanocytes themselves. We have determined membrane damage in pigmented and unpigmented albino mouse melanocytes after ultraviolet A radiation, which is suspected to induce melanoma. Unpigmented cells were much more susceptible to ultraviolet-A-induced membrane permeability than pigmented cells. Unpigmented cells were also more susceptible to ultraviolet-A-induced lipid peroxidation than strongly pigmented cells. Furthermore, unpigmented cells were much more susceptible to ultraviolet-A-induced depletion of glutathione than pigmented cells. Reduced glutathione is known to be a major antioxidant of unpigmented skin cells such as fibroblasts and keratinocytes. To examine whether or not glutathione is also a major antioxidant in melanocytes, melanocytes were depleted of glutathione by means of buthionine sulfoximine. We found that depletion of glutathione in pigmented melanocytes did not change lipid damage induced by ultraviolet A radiation. In unpigmented melanocytes, however, depletion of glutathione significantly increased lipid damage induced by ultraviolet A radiation. Thus, pigmented melanocytes apparently contain antioxidants more potent than glutathione, protecting them from ultraviolet-A-induced membrane damage.     

Traumatic ulcers and pain in adults during orthodontic treatment

In the present investigation the frequency of oral ulcers and pain in 79 adults orthodontic patients was recorded. Only four of all patients had never had oral ulceration during treatment, but 83% of the patients characterized the trouble as minor. About 47% of the patients said that ulcers caused by the fixed appliance were the most annoying part of the treatment, and 38% said that activation of the appliance caused the most discomfort. In about 63% of the patients there was less pain when the treatment had lasted for some months, and in 24% there was no significant change in the discomfort. The pain following activation lasted for only 2-3 days (71%), but 20% had pain for more than 3 days, and five individuals felt pain constantly. The recurrence of aphthous ulceration (RAU) was not significantly affected during the orthodontic treatment, and in only one case was there an increase in the occurrence of herpes labialis.     

Sedation with nitrous oxide compared with no sedation during catheterization for urologic imaging in children

Background Various strategies to mitigate children’s distress during voiding cystourethrography (VCUG) have been described. Sedation with nitrous oxide is comparable to that with oral midazolam for VCUG, but a side-by-side comparison of nitrous oxide sedation and routine care is lacking. Objective The effects of sedation/analgesia using 70% nitrous oxide and routine care for VCUG and radionuclide cystography (RNC) were compared. Materials and methods A sample of 204 children 4–18 years of age scheduled for VCUG or RNC with sedation or routine care were enrolled in this prospective study. Nitrous oxide/oxygen (70%/30%) was administered during urethral catheterization to children in the sedated group. The outcomes recorded included observed distress using the Brief Behavioral Distress Score, self-reported pain, and time in department. Results The study included 204 patients (99 nonsedated, 105 sedated) with a median age of 6.3 years (range 4.0–15.2 years). Distress and pain scores were greater in nonsedated than in sedated patients (P < 0.001). Time in department was longer in the sedated group (90 min vs. 30 min); however, time from entry to catheterization in a non-imaging area accounted for most of the difference. There was no difference in radiologic imaging time. Conclusion Sedation with nitrous oxide is effective in reducing distress and pain during catheterization for VCUG or RNC in children.     

Secondary dentin in replanted teeth--a histometric study

To quantify the secondary dentin formation in replanted teeth, 16 human premolars with a postoperative observation period of 6, 12 and 24 weeks were studied histometrically. In spite of marked intra- and interindividual variations, a regression analysis revealed a significant correlation (r = 0.70) between observation time and the quantity of secondary dentin in the coronal pulp registered by histometry. A comparison with a previous semiquantitative interpretation of the same material showed that the histometric method was more accurate.     

Comparative absorption of atropine from a metered-dose inhaler and an intramuscular injection.

The inhalation of atropine sulfate from a pressurized metered-dose inhaler was investigated in a nonrandomized four-period rising-dose study. Eight healthy, nonsmoking subjects received 1.7, 3.4, and 5.2 mg of atropine sulfate by inhalation and 1.67 mg of atropine free base (equivalent to 2 mg of atropine sulfate) by intramuscular (i.m.) injection. Serum atropine sulfate concentrations were measured over a 24-h period by gas chromatography/mass spectrometry. Mean serum concentrations increased nonproportionally as the inhaled dose increased. Mean peak concentrations were 4.9, 6.1, and 7.9 ng/ml for the inhaled doses and 8.4 ng/ml for the i.m. dose. Typical anticholinergic effects were seen after all doses.     

Antiarrhythmic and electrophysiologic actions of flecainide in animal models

The results of antiarrhythmic testing in a variety of animal models indicate that flecainide acetate has potent antiarrhythmic activity. In these models it is more potent than lidocaine, procainamide and quinidine, as well as a number of investigational agents, and is active against both ventricular and supraventricular arrhythmias from a number of causes. Studies of its effects on the action potential from various cardiac tissues indicate that its primary effect is to slow the rate of rise of the action potential, placing it among the group of drugs commonly referred to as class I agents. In the intact animal, in accordance with its effects on the action potential, flecainide slows conduction throughout the cardiac conduction system, with the most marked effects on His-Purkinje conduction and ventricular activation.     

Binding of human IgA to HCl-extracted c protein from group B streptococci (GBS).

The c beta protein of group B streptococci obtained by HCl extraction appears as a ladder-like pattern in SDS-PAGE when detected by a rabbit anti-c beta serum, and a similar picture is seen when the crude extract is incubated with human IgA and an anti-human IgA conjugate. Affinity-purified c beta antigen and IgA receptors from GBS gave identical pictures in Western blots using rabbit anti-c beta serum. Both the c beta antigen and the IgA receptor are exposed on the surface of GBS as demonstrated by immunofluorescence.