Locomotor stimulant effects of nornicotine: role of dopamine.

Nornicotine (NORNIC) is a tobacco alkaloid and behaviorally active nicotine metabolite in vivo. Previous behavioral research has shown that NORNIC has locomotor stimulant and reinforcing effects in rats similar to that of nicotine. Results from the current study showed that a bilateral lesion of the nucleus accumbens decreased the locomotor stimulant effect of NORNIC across repeated injections. Pretreatment with the dopamine (DA) D1 receptor antagonist SCH23390 did not block the locomotor stimulant effect of NORNIC or the initiation of sensitization following repeated NORNIC administration. The D2 receptor antagonist eticlopride, however, blocked both the stimulant effect and the initiation of sensitization following repeated NORNIC. Additionally, NORNIC was found to increase synthesis and metabolism of DA, with a greater effect in the mesolimbic pathway compared to the nigrostriatal pathway. Taken together, these results suggest that expression of NORNIC-induced locomotor activity is dependent upon ascending dopaminergic mesolimbic projections, providing additional evidence that NORNIC plays a contributory role in tobacco dependence.

Measurements and analysis of criteria pollutants in New Delhi, India.

Ambient concentrations of carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), and total suspended particulates (TSP) were measured from January 1997 to November 1998 in the center of downtown [the Income Tax Office (ITO) located on B.S.G. Marg] New Delhi, India. The data consist of 24-h averages of SO2, NOx, and TSP as well as 8 and 24-h averages of CO. The measurements were made in an effort to characterize air pollution in the urban environment of New Delhi and assist in the development of an air quality index. The yearly average CO, NOx, SO2, and TSP concentrations for 1997 and 1998 were found to be 4810+/-2287 and 5772+/-2116 microg/m3, 83+/-35 and 64+/-22 microg/m3, 20+/-8 and 23+/-7 microg/m3, and 409+/-110 and 365+/-100 microg/m3, respectively. In general, the maximum CO, SO2, NOx, and TSP values occurred during the winter with minimum values occurring during the summer, which can be attributed to a combination of meteorological conditions and photochemical activity in the region. The ratio of CO/NOx (approximately 50) indicates that mobile sources are the predominant contributors for these two compounds in the urban air pollution problem in New Delhi. The ratio of SO2/NOx (approximately 0.6) indicates that point sources are contributing to SO2 pollution in the city. The averaged background CO concentrations in New Delhi were also calculated (approximately 1939 microg/m3) which exceed those for Eastern USA (approximately 500 microg/m3). Further, all measured concentrations exceeded the US National Ambient Air Quality Standards (NAAQS) except for SO2. TSP was identified as exceeding the standard on the most frequent basis.

Exposure to novel environmental stimuli decreases amphetamine self-administration in rats.

Researchers examined whether exposure to novel environmental stimuli reduces drug self-administration. Rats were trained to self-administer amphetamine on a fixed ratio (FR) 5 schedule of reinforcement and then were exposed to novel stimuli during the session. Responding was significantly decreased with exposure to novelty but returned to baseline levels on intervening nonexposure sessions. In 2 subsequent experiments, rats were exposed to novel plastic objects prior to the session. Immediately following exposure, rats were allowed to self-administer amphetamine on an FR 1 schedule, which was increased gradually to an FR 5 either using predetermined increments or on the basis of performance criteria. Exposure to the novel objects significantly decreased acquisition of amphetamine self-administration in both situations. Results suggest that exposure to novel environmental stimuli may be effective at reducing drug self-administration.

Nornicotine pretreatment decreases intravenous nicotine self-administration in rats.

RATIONALE: Nicotine has been shown to be effective as a treatment for reducing tobacco dependence. However, few studies have examined the effect of other nicotinic agonists to determine if they can also decrease nicotine self-administration. OBJECTIVE: The present study determined if nornicotine, a tobacco alkaloid and major nicotine metabolite in brain, could reduce nicotine self-administration in rats. METHODS: Each rat was prepared with an indwelling jugular catheter and trained to self-administer intravenous nicotine (0.03 mg/kg per infusion). After nicotine self-administration stabilized, rats were pretreated with either (-)-nicotine (0, 0.1, 0.3, and 1.0 mg/kg free base) or (+/-)-nornicotine (0, 1, 3, 5.6, and 10.0 mg/kg free base) and assessed for nicotine self-administration. A separate group of rats was maintained on sucrose reinforced responding and pretreated with nornicotine to determine the specificity of the pretreatment effect. In another group of rats, the time course of the pretreatment effect of either (-)-nicotine (0.56 and 1.0 mg/kg) or (+/-)-nornicotine (5.6 and 10.0 mg/kg) was examined. RESULTS: Nicotine and nornicotine each produced a dose-dependent decrease in nicotine self-administration. Furthermore, the decrease in nicotine self-administration in response to the 5.6 mg/kg nornicotine pretreatment was specific to nicotine self-administration, as this dose did not decrease sucrose reinforced responding in tolerant animals. In addition, within the dose range tested, the suppressant effect of nornicotine had a two-fold longer duration than that of nicotine (120 versus 60 min). CONCLUSION: These results suggest that nornicotine may be an effective treatment for tobacco dependence.

Intranasal civamide for the acute treatment of migraine headache.

The objective of this study was to investigate the safety and efficacy of intranasal civamide for the acute treatment of migraine headache with or without aura. Civamide is a vanilloid receptor agonist and neuronal calcium channel blocker that inhibits the neuronal release of excitatory neurotransmitters (e.g. calcitonin gene-related peptide (CGRP) and substance P (SP)) and depletes the neurones of the trigeminal plexus of their neurotransmitter content. Applied intranasally, the release of neurotransmitters to meningeal and dural blood vessels should be decreased, along with the resultant vasodilatation, plasma extravasation, and histamine/serotonin release. Subsequent migraine headache pain may also be diminished. Thirty-four patients were enrolled into a double-blind study of intranasal civamide, and randomized to receive a single dose of either 20 microg or 150 microg of civamide, for the treatment of a single migraine headache, with or without aura, of moderate to severe pain. At 2 h post-dose, 55.6% of patients treated with either dose had a decrease in pain severity, with 22.2% of patients being pain-free. At 4 h post-dose, 72.7% of patients treated with either dose had a decrease in pain severity, with 33.0% of patients being pain-free. Adverse events were similar for both dosages, with 91.2% of patients experiencing nasal burning and 44.1% of patients experiencing lacrimation. No systemic side-effects were observed. Based upon the results of this study, intranasal civamide may be effective in the acute treatment of migraine headache. Given civamide's proposed mechanism of action, intranasal civamide should be substantially more effective for prophylaxis than acute treatment of migraine. A study evaluating its efficacy in prophylaxis of migraine is currently planned.

D-amphetamine facilitation of morris water task performance is blocked by eticlopride and correlated with increased dopamine synthesis in the prefrontal cortex.

The effect of posttraining D-amphetamine on Morris water task (MWT) performance was analyzed in this study by training rats using a single training trial per day procedure. In addition to acquisition latency, learning was assessed by a probe trial given 24 h after the last training trial. Rats given immediate post-trial D-amphetamine demonstrated improved performance over saline rats on both acquisition and the probe trial. An analysis of the mechanisms underlying facilitation revealed that eticlopride (a D2 antagonist) blocked D-amphetamine's facilitatory effects on the probe trial and dopamine synthesis was increased in the medial prefrontal cortex in the D-amphetamine group relative to controls. These results show that chronic administration of posttraining D-amphetamine facilitated MWT performance, and this facilitation may be mediated by the dopaminergic system and dopamine synthesis in the prefrontal cortex.

Pharmacokinetics of doxepin in subjects with pruritic atopic dermatitis.

BACKGROUND: Doxepin applied topically by itself or in combination with triamcinolone acetonide is a safe and effective treatment for atopic dermatitis. OBJECTIVE: We evaluated the pharmacokinetic profile of doxepin and desmethyldoxepin after topical application of doxepin hydrochloride 5% cream alone or in combination with 0.025% triamcinolone acetonide (doxepin/TAC). METHODS: Twenty-four subjects with atopic dermatitis received either doxepin or doxepin/TAC cream 4 times daily for 7 days in a randomized, double-blind, controlled trial. Serum samples were obtained and pharmacokinetic parameters estimated from the dose-normalized serum concentrations of doxepin and desmethyldoxepin. Efficacy and adverse experiences were determined by physician and subject evaluations. RESULTS: Pharmacokinetic parameters (K(e ), t(1/2 ) and AUC) calculated in 9 subjects (doxepin/TAC = 4 subjects, doxepin = 5 subjects) with detectable serum concentrations were similar for both groups. Pruritus relief and lessening of pruritus severity were significantly greater with doxepin/TAC than doxepin alone. CONCLUSION: Topically applied doxepin is safe and effective therapy for pruritus.

Graft-like plantar lesion secondary to possible dorsal-to-ventral cutaneous transposition.

We describe a 3-year-old male patient with an unusual congenital lesion on the plantar surface of the left foot that had been asymptomatic until shortly before presentation. Histologic examination of the plaque revealed a thinner keratin layer, increased pigmentation, and a pilosebaceous unit with a visible vellus hair. We tentatively hypothesize from this single case that a disruption in the normal sequence of events of morphogenesis, and particularly in dorsal-to-ventral orientation, may have occurred in this patient.

Fluorescence photography in the evaluation of hyperpigmentation in photodamaged skin.

BACKGROUND: Treatment-related changes in hyperpigmentation are difficult to quantify with visible light photography, especially when the changes are subtle. OBJECTIVE: Our purpose was to determine the utility and reliability of fluorescence photography to measure changes in mottled and diffuse hyperpigmentation. METHODS: Thirty-two subjects, with mildly to moderately photodamaged skin, completed a 36-week, double-blind, vehicle-controlled study of tretinoin cream 0.025%. Clinical evaluation of hyperpigmentation as well as standard flash photographs and fluorescence photographs were obtained at baseline and week 36. RESULTS: The fluorescence photographs were evaluated blindly and yielded macule counts that decreased significantly from baseline in tretinoin-treated subjects compared with vehicle-treated subjects (31% vs 11% decrease; p = 0.02). Diffuse hyperpigmentation, as evaluated from the fluorescence photographs, decreased 16% from baseline for tretinoin-treated subjects and increased 5% for vehicle-treated subjects (p < 0.01). No significant differences in mottled or diffuse hyperpigmentation were observed between groups through clinical evaluation. CONCLUSION: Fluorescence photography is a noninvasive method that is sensitive in the evaluation and quantification of distribution and changes of mottled and diffuse hyperpigmentation.

Oxyhemoglobin is a quantifiable measure of experimentally induced chronic tretinoin inflammation and accommodation in photodamaged skin.

Chronic exposure to a weak irritant leads to inflammatory changes which may be followed by pigmentary changes and accommodation. The inflammatory responses to acute exposure to an irritant have been extensively studied. This study investigated quantitatively the inflammatory reactions produced in photodamaged skin with chronic application of a weak chemical irritant (tretinoin cream 0.025%) over a period of 9 months (36 weeks). Forty-eight subjects with moderately to severely photodamaged skin were enrolled in a 36-week, double-blind placebo-controlled study. Tretinoin cream was applied nightly on the distal two thirds of one dorsal forearm and placebo on the other. The proximal third of each dorsal forearm received no treatment and served as control. Clinical assessments and diffuse reflectance measurements were made at 7 time points during treatment. Apparent concentrations of oxyhemoglobin (HbO2), deoxyhemoglobin (Hb) and melanin were estimated by analysis of the diffuse reflectance spectra. No changes were observed in the apparent HbO2 or the Hb concentration of the placebo-treated or control sites, thus establishing a reliable baseline. The apparent HbO2 concentration of the tretinoin-treated sites increased significantly from baseline to a maximum at 12-18 weeks of treatment, then returned to baseline with continued applications. The changes in HbO2 concentration agreed closely with clinical assessments of erythema. The apparent melanin concentration, corresponding to diffuse hyperpigmentation, showed a large seasonal decrease in both the control and the treated sites, with an additional decrease in the treated sites between 12 and 18 weeks. Erythema appeared after repeated applications and eventually resolved under continuous treatment. The maximum decrease in hyperpigmentation occurred simultaneously with the maximum increase in erythema.

Polarized light photography enhances visualization of inflammatory lesions of acne vulgaris.

BACKGROUND: Polarized light photography has been used to selectively differentiate surface from subsurface features of photoaged skin. OBJECTIVE: Our purpose was to compare acne assessments obtained from clinical evaluations with assessments from photographs obtained with flash photography and with perpendicular polarized light photography. METHODS: Assessments of acne with the Cunliffe scale were made of 32 subjects. Retrospective evaluations of standard and perpendicular polarized light photographs were made in a blinded fashion by a panel of evaluators. RESULTS: Visualization of inflammatory acne lesions was enhanced with perpendicular polarized light photography, with clear delineation of erythematous borders. Acne assessments with the use of a Cunliffe scale were significantly higher (p = 0.001) from perpendicular polarized light photographs than for clinical evaluations. CONCLUSION: Polarized light photography enhances visualization of inflammatory acne lesions in a manner not possible with conventional flash photographs, permitting accurate evaluation of the extent of disease and the effectiveness of therapy.

Fluorescence photography in the evaluation of acne.

BACKGROUND: Quantification of acne remains a challenge. It may be difficult to identify lesions by standard flash photography. Previous studies have shown that foci of light in fluorescence photographs correspond to high protoporphyrin IX production by Propionibacterium acnes in open comedones, follicles, and inflammatory lesions. OBJECTIVE: Our purpose was to study the utility of fluorescence photography for evaluation of acne. METHODS: Forty subjects with mild to moderate acne vulgaris were randomly selected to apply either clindamycin 1% topical solution or vehicle twice daily. Counts of acne lesions and flash and fluorescence photographs were obtained at baseline, and at 4, 8, and 12 weeks. RESULTS: At 12 weeks, the treatment group had a larger percentage change in open comedones, less fluorescence in all areas assessed, and a larger percent decrease in fluorescence than the vehicle group. CONCLUSION: Fluorescence photography appears to be a useful tool to chart the course of acne treatment.

Evaluation of cutaneous reactivity to recently marketed dermatologic products.

BACKGROUND: Reports of purported sensitization reactions to widely used prescription dermatologicals have raised questions concerning the clinical significance of these reports. The current study was designed to compare irritant and sensitization potentials of such marketed products and to evaluate the risks involved in their usage. METHODS: One hundred and eight healthy adult volunteers were evaluated for primary irritation and hypersensitivity following application under a double-blind paradigm of eight leading prescription dermatologic products and the vehicle cream of one product according to an intensified version of the Shelanski and Shelanski "Repeated Insult Patch Test." RESULTS: No clinically significant irritant or sensitization reactions were associated with applications of topical formulations containing clobetasol propionate, doxepin hydrochloride, metronidazole, mupirocin, oxiconazole nitrate, and terbinafine hydrochloride. The doxepin hydrochloride cream vehicle was also found to be nonirritating and nonsensitizing. Both calcipotriene and ketoconazole were moderate irritants and possible sensitization reactions were also associated with ketoconazole. CONCLUSION: Although every topically applied chemical has the potential to cause an adverse response in some individuals, the data obtained in this study for eight commercially available prescription dermatologic products indicate that most are quite safe and have very low risks of clinically significant irritation or sensitization.

Polarized light photography in the evaluation of photoaging.

BACKGROUND: The clinical characteristics of photodamaged skin, such as coarse and fine wrinkling, sallowness, hyperpigmentation, tactile roughness, laxity, and erythema, are not accurately evaluable from photographic records. OBJECTIVE: The purpose of this study was to develop accurate and reproducible photographic techniques that generate an evaluable record of the characteristics of photodamaged skin. METHODS: The method used involved illumination and photography through polarizing filters (polarized light photography). RESULTS: Polarized light photography generates images that selectively enhance either the surface features or the subsurface features of the skin, providing an accurate and evaluable record for evaluation of photodamaged skin. CONCLUSION: Polarized light photography, when coupled with precise framing and mapping, yields an accurate and evaluable record of photodamaged skin.

A single parameter, oxygenated hemoglobin, can be used to quantify experimental irritant-induced inflammation.

To quantify the dose-response relation of irritant-induced erythema, we examined inflammation in human skin after application of an irritant, using perpendicular polarized photography and diffuse reflectance spectroscopy as compared to clinical visual scoring. The ventral forearms of 11 healthy subjects were patch-tested for 24 h under occlusion in finn chambers with five concentrations of the irritant sodium lauryl sulfate. The tested sites and three control sites were evaluated clinically for erythema at 24, 48, and 72 h after occlusion, photographed using standard and perpendicular polarized photography, and measured by diffuse reflectance spectroscopy. All photographs were evaluated for erythema by three investigators. Diffuse reflectance spectra were analyzed, and changes in apparent oxyhemoglobin and deoxyhemoglobin concentrations were estimated. Clinical and photographic assessments of erythema yielded similar linear dose-response relations. A linear dose-response relation, with no minimum threshold, also was obtained for changes in the apparent oxyhemoglobin concentration with increasing irritant dose, whereas the apparent deoxyhemoglobin concentrations were unchanged with increasing dose. These results show that diffuse reflectance spectroscopy permits the characterization of irritant-induced inflammation in terms of a single parameter, the apparent concentration of oxyhemoglobin, and that irritant-induced inflammation primarily involves the capillaries and the superficial arterial plexus.

Characterization of sciellin, a precursor to the cornified envelope of human keratinocytes.

The cornified envelope, located beneath the plasma membrane of terminally differentiated keratinocytes, is formed as protein precursors are cross-linked by a membrane associated transglutaminase. This report characterizes a new precursor to the cornified envelope. A monoclonal antibody derived from mice immunized with cornified envelopes of human cultured keratinocytes stained the periphery of more differentiated cells in epidermis and other stratified squamous epithelia including hair and nails. The epitope was widely conserved among mammals as determined by immunohistochemical and Western analysis. Immunoelectron microscopy localized the epitope to the cell periphery in the upper stratum spinosum and granulosum of epidermis. In the hair follicle, the epitope was present in the internal root sheath and in the infundibulum, the innermost aspect of the external root sheath. The antibody recognized a protein of relative mobility (M(r)) 82,000, pI 7.8. The protein was a transglutaminase substrate as shown by a dansylcadaverine incorporation assay. Purified cornified envelopes absorbed the reactivity of the antibody to the partially purified protein and cleavage of envelopes by cyanogen bromide resulted in release of immunoreactive fragments. The protein was soluble only in denaturing buffers such as 8 M urea or 2% sodium dodecyl-sulfate (SDS). Partial solubility could be achieved in 50 mM TRIS pH 8.3 plus 0.3 M NaCl (high salt buffer); the presence of a reducing agent did not affect solubility. Extraction of cultured keratinocytes in 8 M urea and subsequent dialysis against 50 mM TRIS pH 8.3 buffer resulted in precipitation of the protein with the keratin filaments. Dialysis against high salt buffer prevented precipitation of the protein. The unique solubility properties of this protein suggest that it aggregates with itself and/or with keratin filaments. The possible role of the protein in cornified envelope assembly is discussed. We have named this protein Sciellin (from the old english "sciell" for shell).

Involucrin-like proteins in non-primates.

A monoclonal and two polyclonal antibodies to human involucrin were used to look for involucrin epitopes in other species. All antibodies react strongly with the same proteins of monkey, and both polyclonal antibodies react with specific proteins of cow and dog. One of the polyclonal antibodies also reacts with proteins of sheep, guinea pig, rat, and finback whale. The immunoreactive proteins from cow and dog could be purified using a procedure developed for human involucrin. The reaction with the purified dog protein could be blocked by purified human involucrin. The results suggest that involucrin-like proteins have a wider species distribution than originally appreciated.

The pancornulins: a group of basic low molecular weight proteins in mammalian epidermis and epithelium that may function as cornified envelope precursors.

1. A monoclonal antibody (HCE-2) to human epidermal and epithelial cornified envelopes identified a group of soluble basic protein precursors. 2. Using HCE-2, envelope-like staining was observed in the epidermis and stratified squamous epithelium of a number of mammalian species. 3. Basic polypeptides reactive to HCE-2 varied in size and number among the different animals. 4. In those species studied, HCE-2-reactive peptides were substrates for transglutaminase and protease treatment of cornified envelopes released HCE-2-reactive degradation products. 5. These results suggest a new family of proteins in mammalian epidermis that may function as cornified envelope precursors.

NM1 keratinocyte line is cytogenetically and biologically stable and exhibits a unique structural protein.

We have previously described a human keratinocyte line, NM1, which had been carried for more than 400 doublings, was trisomic for chromosome 8, and appeared to make a number of structural proteins characteristic of keratinocytes. This line has now been carried for more than 800 doublings and grows with the same vigor. It reaches confluence in 7 to 10 days and can be grown without a feeder layer for more than 15 passages. Its karyotype has remained 47,XY, +8. The current NM1 cells make readily detectable amounts of 67 kd and 48 kd keratins, and it has been established that the previously poorly resolved 58 kd band actually consists of 58 kd and 59 kd bands. We have also found that the apparent 56 kd band consists of the 56 kd and 56.5 kd bands. A unique basic polypeptide precursor of the cornified envelope has been discovered in the NM1 line. Although similar in charge to one in normal cells it is lower in molecular weight.