Computer-assisted visualization of the rat epididymis: a methodological study based on paraffin sections autometallographically stained for zinc ions.

A concept for the computer-assisted visualization of tubular organs is presented. Unmarked histological zinc-stained serial sections from the epididymis of the Wistar rat were aligned to demonstrate the concept. Virtual images were made through the aligned sections and served as controls for the alignment process. Animation of the serial sections and the virtual images revealed new information about the structure of the organ under investigation. The analysis was used to upgrade the anatomical knowledge of rat epididymis by describing how the epididymal duct runs through the structure. The proximal parts of the epididymis contain large communicating septa of connective tissue dividing the caput and the upper part of the corpus epididymidis into segments. The tortuousness was high in the caput with many turns within a small area of the epididymis, whereas longer loops were found in the lower part of the corpus and cauda epididymidis. The tube of the vas deferens was found to become an integrated part of the ductal system in the cauda epididymidis, although it was histologically easy to distinguish from the epididymal duct. The total number of cross-sections of the ductus epididymidis in the 2254, 15-microm-thick, tissue sections analysed was 104700, giving a minimum length of the ductal system of 1.5 m.

Impact of epidermal thickness on purpura from the pulsed dye laser.

BACKGROUND AND OBJECTIVE: To clarify whether epidermal thickness is of importance to the purpuric reaction from treatment with the pulsed dye laser (PDL). STUDY DESIGN/MATERIALS AND METHODS: Fifteen fairly pigmented volunteers were laser treated in two test regions of varying epidermal thicknesses: normal buttock skin and ultraviolet B (UVB)-exposed buttock skin. Laser treatments were performed with the flashlamp-pumped PDL (585 nm). Fluences ranged from 3-6.5 J/cm2, spot size was 7 mm, and each volunteer received at least six fluences in each treatment region. Assessment of the response was based on clinical evaluation (threshold dose to purpura 10 minutes and 1 day after treatment) and skin reflectance-evaluated redness (1 and 6 days, 2 and 6 weeks after treatment). RESULTS: The total epidermal thickness differed between the unexposed buttock skin (median, 72.7 microm) and the UVB-exposed buttock skin (87.2 microm) (P < 0.01). There was no correlation between the epidermal thickness and the threshold dose to induce purpura 10 minutes and 1 day after laser exposure. Skin reflectance revealed no correlation between the epidermal thickness and the skin reflectance evaluated redness on 1, 6 days, and 2 weeks postoperatively. A dose-response relation was seen within the two test regions; 6 weeks after laser exposure, there was no remaining laser-induced skin redness. CONCLUSION: The epidermal thickness is unimportant to the purpuric reaction after PDL treatment.

Epidermal thickness measured by light microscopy: a methodological study.

BACKGROUND/AIMS: Epidermal thickness is frequently measured by light microscopy. The preservation and staining methods may alter the proportions of the specimens and thereby influence the measurements. The aim of the present study was to describe: 1) a standardized light microscopic method to quantify the thicknesses of the stratum corneum and the cellular epidermal layers, 2) the variations according to preparation and staining techniques, and 3) the observer variability. METHODS: One hundred and sixty skin biopsies from 67 human volunteers were included. The cellular epidermis and the stratum corneum were estimated in sections preserved by freezing and subsequent preparation with cryostat or formalin-paraffin techniques. The slides were stained with haematoxylin-eosin or er-ythrocin, and thicknesses of the stratum corneum and the cellular epidermis were measured by a calibrated ruler and an ocular grid, respectively. RESULTS: The formalin fixation gave slightly higher values for the cellular epidermis than the cryostat technique. In comparison to erythrocin staining, haematoxylin-eosin gave a significantly thinner stratum corneum. No significant inter- or intra-observer variation was found for the thickness of the stratum corneum assessed twice by two experienced observers. However, the two observers differed slightly from each other on the thickness of the cellular epidermis. CONCLUSION: It is found that thickness measurements of the stratum corneum and the cellular epidermis are reliably performed on cryostatic cut sections stained with haematoxylin-eosin.

Urocanic acid isomers: relation to body site, pigmentation, stratum corneum thickness and photosensitivity.

Urocanic acid (UCA), present in the stratum corneum as trans-UCA, absorbs ultraviolet (UV) radiation and isomerizes to cis-UCA. Cis-UCA has been demonstrated to initiate suppression of selected immune responses in several experimental systems. Topical application of UCA-containing products reduces UV-induced erythema, but a role for endogenous UCA in photoprotection has not been reported. In this study the relationship between UCA isomers, pigmentation, minimal erythema dose (MED), and stratum corneum thickness was investigated. Pigmentation, concentration of total UCA, and the percentage present as the cis-isomer was measured in 36 healthy subjects, skin type I-IV, at six UV-exposed and nonexposed body sites: forehead, chest, back, outer upper arm, inner upper arm, and buttock. The MED was determined by phototesting on buttock skin, and a punch biopsy for measurement of stratum corneum thickness was taken adjacent to the site of the phototest. The percentage of cis-UCA was significantly higher in UV-exposed than on nonexposed areas. A small intraindividual variation in total UCA was found, being high on the buttock and the arm, lowest on the forehead. The subject to subject variation of total UCA was considerable at all body sites. No correlation was found between total UCA and MED, skin type, pigmentation, or stratum corneum thickness.

Epidermal thickness, skin pigmentation and constitutive photosensitivity.

The important factors for UV sensitivity in humans are considered to be the skin pigmentation and the epidermal thickness. In this study on 73 Caucasians (age 20-85 years), we investigated in UV unexposed buttock skin the relationship between the UV sensitivity and constitutive skin pigmentation and thickness of the stratum corneum and the cellular part of the epidermis, in 34 normal people and in 39 skin cancer patients (20) patients with cutaneous malignant melanoma and 19 patients with basal cell carcinoma of the skin). Skin pigmentation was measured by skin reflectance spectroscopy, and UV sensitivity by phototest with a solar simulator. Thicknesses of the stratum corneum and the cellular part of the epidermis were determined by light microscopic evaluation of skin biopsies from the phototest areas. We found that epidermal thickness was independent of skin type and was not correlated to constitutive skin pigmentation. Thickness of the stratum corneum was statistically not different in normal persons and in skin cancer patients (P = 0.41) and was independent of gender (P = 0.61) and age (P = 0.56), while thickness of the cellular epidermis decreased with age (P < 0.01). Stratum corneum thickness was found to be of minor importance for the constitutive UV sensitivity (accounting for on average 11% of the total photoprotection), which was mainly determined by the constitutive skin pigmentation (goodness-of-fit for correlation r = 0.83). A theoretical model for the relationship of UV dose to induction of clinical erythema grade and skin pigmentation and thickness of the stratum corneum was developed. Objective measurements of skin pigmentation in UV unexposed skin by skin reflectance spectroscopy in Caucasians, normal people and people with cutaneous malignant melanoma and basal cell carcinoma of the skin predicts the constitutive UV sensitivity with a high degree of precision.

Side effects from dermatological laser treatment related to UV exposure and epidermal thickness: a murine experiment with the copper vapor laser.

BACKGROUND AND OBJECTIVE: The intention of the present study was to clarify whether UV-exposure prior to laser treatment of albino mouse skin may influence laser-induced side effects and if a possible influence may be explained by epidermal thickening. STUDY DESIGN/MATERIALS AND METHODS: Albino, hairless mice were irradiated 0, 8, and 22 consecutive times with simulated solar UV (1.4 J/cm2 per treatment). Subsequently, two areas on the back of the mice (1.26 cm2 each) were treated with a copper vapor laser that was connected to a Hexascan. The beam diameter was 1 mm, pulse duration 200 msec, and intensities 0.6 W, 0.8 W, and 1.0 W. Laser-induced wounds, scars, and histologically evaluated fibrosis were evaluated. RESULTS: We found that mice irradiated with UV before laser treatment developed smaller wounds, smaller texture change areas, and less fibrosis as compared with nonirradiated control groups, and significant, negative correlations were demonstrated between epidermal thicknesses (stratum corneum, the cellular part of epidermis, and the entire epidermis) and laser-induced skin reactions. A dose response was obtained between laser intensities and laser-induced skin reactions, which tended to be more severe in the cranial back location as compared with the caudal back location. Epidermal layers increased significantly after eight consecutive times of UV irradiation and increased to a steady level after 22 times of irradiation. CONCLUSION: We conclude that UV exposure prior to laser treatment of albino mice reduced laser-induced side-effects, which could be explained by increased epidermal thickening. Variations in epidermal thickness might thus contribute to variations in clinical response to dermatological laser treatment with the copper vapor laser.

Presynaptic modulation of sympathetic nerve transmission--an element in vasomotor control.

We have earlier presented evidence that adenosine may create vasodilation via presynaptic inhibition of sympathetic nerve fibers to muscle arterioles. In the present study the effect of selective adenosine antagonists on arteriolar diameter was investigated, using an autoperfused frog muscle (m. cutaneus pectoris). During application of the antagonists arteriolar diameter reductions were observed in the transparent, transilluminated muscle. The sulfonylated xanthine derivatives 8-(p-sulfo)phenyltheophylline (8-PS phi T), 8-(m-sulfo)phenyltheophylline (8-MS phi T) and 1,3-dipropyl-8-p-sulfonphenylxanthine (DPSPX) are all considered to be selective competitive adenosine antagonists without unspecific intracellular effects. Topical application of each of these compouns on resting muscle resulted in a dose-dependent arteriolar contraction. The constriction was immediately reversed by addition of the adrenergic alpha-receptor blocker phentolamine (7.1 x 10(-5) M), indicating that the arteriolar contraction was due to activation of postjunctional alpha-receptors present in vascular smooth muscle. Also, the A1-selective adenosine agonist (-)-N6-(R-phenylisopropyl)-adenosine (R-PIA) eliminated the arteriolar constriction. These effects suggest, that the xanthine derivatives release the sympathetic nerve terminals from inhibition by endogenous adenosine. When nerve fibers were blocked by tetrodotoxin (TTX), 3 x 10(-6)M or when the frogs had been chemically sympathectomized with 6-hydroxydopamine (6-OHDA), no significant arteriolar contraction was observed during adenosine antagonist administration, complying with the view that in resting muscle endogenous adenosine acts presynaptically to inhibit sympathetic nerve terminals. These results suggest that presynaptic adenosine effects are not only involved in regulation of frog skeletal muscle blood flow in response to activity, but also play a role in the control of arteriolar tone in resting muscle.

Antifibrinolytic prevention of alveolitis sicca dolorosa.

In a double-blind study dental cones containing the antifibrinolytically active propylic ester of p-hydroxybenzoic acid (PEPH), sulfanilamide and sulfathiazol or placebo were placed in dental sockets following removal of impacted mandibular third molars on 95 consecutive patients, 50 women and 45 men. The duration of the operation, the type of surgeon, preoperative symptoms and the use of peroral anticonception were recorded. The patients were asked to return to the clinic on the seventh postoperative day, and it was then noted whether the healing was disturbed by Alveolitis Sicca Dolorosa (ASD) or not. Statistical analysis showed a significantly prophylactic effect of PEPH against ASD. The prophylactic effect was most pronounced in the group of male patients without preoperative symptoms and in the group of patients operated by dental students. It could not be demonstrated that the sulfa drugs in the cones were of any benefit to the healing of the socket.

A simplified model for teaching minor oral surgery.

A teaching model, specially constructed for the purpose of training senior dental students in the use of surgical instruments, is described. The advantages of this model are inexpensiveness and reproducible simulated surgical situations securing a uniform teaching objective.