Extracellular stimulation of epidermal DNA synthesis

The removal of the topmost cell layers of the epidermal stratum corneum by stripping initiates a series of biochemical events which alters the normal homeostatic control of and results in the acceleration of the cell cycle in basal cells which are ten to twenty cell layers removed from the site of stripping. One measure of accelerated events is a stimulation of thymidine incorporation into epidermal DNA at time intervals following stripping. Two peaks of maximal stimulation occur between 12 and 24 hr and 48 and 54 hr after stripping. Stimulation of thymidine incorporation into epidermal DNA by limited stripping is a useful technique for studying the stripping-initiated signal at the stratum corneum and its subsequent translation at the proliferative cell receptor site.     

Phototherapy of cancer and atheromatous plaque with texaphyrins

The incidence of nonmelanoma skin cancer, including both squamous cell carcinoma and basal cell carcinoma, is a significant health problem in the United States. Actinic keratosis (AK), the precursor of cutaneous squamous cell carcinoma, is a major risk factor for nonmelanoma skin cancer. In addition, AKs are tissue targets for the identification of biomarkers for use in chemopreventive studies. The biomarker addressed in this study is epidermal cell proliferation, as quantitated by proliferating cell nuclear antigen (PCNA). Shave biopsies were obtained from AKs, tissue immediately adjacent to AKs, normal-appearing, upper-medial arm skin, and non-sun-exposed skin from 19 subjects. When any degree of PCNA staining was considered positive (semiquantitative 1-4 scale), there was a significant difference and a progressively increasing mean PCNA labeling index (LI) in the total epidermis (basal and suprabasal layers), beginning with non-sun-exposed buttock skin, with the lowest LI (2.5 + or - 1.6%), followed by upper-medial arm skin (12.3 + or - 7.4%; P = 0.0015), skin adjacent to AKs (19.2 + or - 12.2%; P = 0.0218), and finally, AKs with the highest LI (34.6 + or - 20.1%; P = 0.0017). This same pattern was observed when the epidermis was separated into basal and suprabasal layers, with the exception of a nonsignificant result for upper-medial arm skin compared with adjacent skin in the basal layer (P = 0.3981). PCNA LIs were also analyzed separately by staining intensity (i.e., scores of 1-4). The PCNA LI in skin with varying degrees of sun damage and/or histological atypia is a candidate surrogate end point biomarker for skin cancer chemoprevention studies.     

Wounding alters epidermal connexin expression and gap junction-mediated intercellular communication

We show that connexin expression and in vivo patterns of communication were dramatically altered in response to epidermal wounding. Six hours after injury, Cx26 was up-regulated in the differentiated cells proximal to the wound, but was down-regulated in cells located at the wound edge. In contrast, Cx31.1 and Cx43 were down-regulated in cells both peripheral to and at the wounded edge. These patterns of altered connexin expression were detectable as early as 2 h after wounding and were most pronounced in 24-h old wounds. Increased expression of Cx26 was still evident in the hyperproliferative epidermis of 6-day old wounds. In vivo dye transfer experiments with Lucifer yellow and neurobiotin confirmed that junctional communication patterns were altered in ways consistent with changes in connexin expression. The data thus suggest that intercellular communication is intimately involved in regulating epidermal wound repair.     

Cutaneous malignant melanoma in southern Sweden 1965, 1975, and 1985. Prognostic factors and histologic correlations

An in vitro model was established to investigate factors underlying the sensory hyperinnervation of neonatal rat skin wounds that has been observed in vivo (Reynolds and Fitzgerald, J. Comp. Neurol. 358 (1995) 487-489). Explants of normal and wounded rat dorsal foot skin were co-cultured with explants of embryonic chick or newborn rat dorsal root ganglia for 24 h and the number of sensory neurites counted. Explants of skin surrounding a wound made at birth were taken 3 (P3) or 10 (P10) days later and compared with normal skin of the same age. In addition, explants were taken from adult skin wounded 3 and 10 days earlier. At P3, normal skin induced weak neurite outgrowth (mean 13.1 +/- 2.1 neurites per ganglion explant) but skin that had been wounded 3 days earlier, at birth, induced three times more neurite outgrowth (37.8 +/- 3.3). Ten days after wounding at birth, neurite outgrowth was still substantial (40.9 +/- 3.3) although at that age (P10), even normal skin stimulates substantial growth (37.4 +/- 2.9). Normal adult skin also stimulated neurite outgrowth (28.7 +/- 0.45) but this was not increased by wounding 3 or 10 days earlier, and this was enhanced 3 days but not 10 days after wounding. Anti-NGF (nerve growth factor) added to the culture medium blocked the constitutive neurite stimulating activity from normal P10 and adult skin but was ineffective in blocking the neurite stimulating activity produced by neonatal wounding. It is concluded that skin wounding at birth results in release of one or more sensory neurotrophic factors that stimulate rat and chick dorsal root ganglia neurite outgrowth for at least 10 days, but which do not include NGF.     

Cell kinetics of head and neck cancers

We measured the tumor cell proliferative rate in 26 patients with head and neck cancer, 22 of which were squamous cell carcinomas (SCCs). Patients received sequential infusions of iododeoxyuridine and bromodeoxyuridine, after which the tumor was biopsied and studied. The percentage of labeled cells [labeling index (LI)] in well-differentiated SCCs was 20.4 +/- 2.7% (mean +/- SE) and 23.8 +/- 2.1% in moderately differentiated SCCs (P = 0.135). The LIs of two poorly differentiated SCCs were 39.4 and 55.9%. The LI was 2.5% in a high-grade lymphoepithelioma and 24.8% in a malignant lymphoma. In one well-differentiated and one poorly differentiated mucoepidermoid tumor, the LIs were 3.0% and 29.1%, respectively. S-phase duration time measurements ranged from 5.1-21.5 h (12.8 +/- 1.5). The calculated potential doubling times ranged from 18.8-84.5 h (47.3 +/- 6.7). The duration of G2 was between 90 and 180 min. To track the fate of labeled cells, in four patients a repeat biopsy was obtained 7-14 days after the iododeoxyuridine/bromodeoxyuridine infusion. These patients did not receive treatment between the biopsies. Due to the dilution of the label, most labeled cells in the second biopsy demonstrated a "fragmented" pattern resulting from repeated cell divisions. In two patients, however, 25% of cells in the second biopsy had undiluted label, suggesting that these cells had not divided after incorporating iododeoxyuridine/bromodeoxyuridine. On Day 7 labeled cells migrated to keratinized parts of tumors and to necrotic foci. Thus, the arrest of cell cycle transition, tumor cell differentiation, and cell death may be major routes of tumor cell loss from the proliferative compartment. This may explain the difference between very short potential doubling times and the actual rate of tumor growth.     

Strong induction of activin expression after injury suggests an important role of activin in wound repair

Activins are members of the transforming growth factor beta (TGF beta) superfamily, which comprises a growing group of dimeric proteins. TGF beta and several other members of this superfamily are known to play an important role in wound healing. However, expression of activin during wound healing has not been demonstrated so far. In this study we have analyzed the expression pattern of activin and activin receptors in normal and wounded skin. We found a large induction of activin A and a minor induction of activin B mRNA expression 1 day after skin injury and high expression levels of activin A and B were found within the first 7 days after wounding. At 13 days after injury, expression of activin A mRNA had returned to the basal level, whereas high levels of activin B persisted. In situ hybridization studies revealed expression of activin A in the granulation tissue below the wound and activin B in the hyperproliferative epithelium at the wound edge and in the migrating epithelial tongue. All known types of activin receptors as well as the activin binding protein follistatin were expressed in normal and wounded skin. However, no significant induction of receptor gene expression was seen during the repair process. The distribution of activins and activin receptors in the wound suggests multiple autocrine and paracrine activities of the ligands during wound healing. Our data provide evidence for a novel function of activin and indicate that--besides TGF beta s themselves--other members of this superfamily might also play an important role in tissue repair.     

The bone marrow stromal environment is a major factor in myeloma cell resistance to dexamethasone

The expression of several markers of epithelial cell proliferation was analyzed to establish baseline data for future chemoprevention studies of oral premalignant lesions. Punch biopsies (n = 60) from three different sites of oral mucosa (bucca, lateral tongue, and the floor of the mouth) were obtained from 20 normal donors of both sexes. After formaldehyde fixation and paraffin embedding, immunohistochemistry was used to detect the proliferation markers Mib-1, cyclin D1, and centromere-associated protein CENP-F. Analysis of sections stained for the three markers showed similar patterns, i.e., a low labeling index (LI) in the basal layer and a high LI in the parabasal layer at all three intraoral sites. No proliferative activity was seen above the parabasal layer (superficial layer). All sites showed similar Mib-1 LI values for the proliferative markers. The tongue epithelium exhibited higher parabasal LIs of cyclin D1 and CENP-F than did the other two sites. No significant differences were detected between smokers and nonsmokers. The data from normal mucosa were compared with those from low (n = 30)- and high (n = 17)-grade dysplastic leukoplakias. The Mib-1 LI showed a very significant change, with a 9-fold increase in the basal layer LI in dysplastic leukoplakias. Cyclin D1 and CENP-F showed similar trends with increments of up to 7-fold in the basal layer of high-grade dysplasia. Although the proliferative activity of the parabasal layer was similar in normal and leukoplakic epithelia, the superficial layer showed a significant increment in proliferative activity mainly in high-grade leukoplakia. These studies suggest that proliferation markers in the basal and superficial cells of premalignant lesions may serve as surrogate end point biomarkers for chemoprevention trials.     

Focal transgene expression associated with papilloma development in v-Ha-ras-transgenic TG.AC mice

The homozygous transgenic mouse line TG.AC contains a v-Ha-ras transgene and rapidly develops epidermal papillomas in response to either wounding or treatment with tumor promoters such as 12-O-tetradecanoylphorbol-13-acetate (TPA). The transgenic v-Ha-ras protein product was detected in all papillomas removed from TPA-treated TG.AC mice but not in vehicle- or TPA-treated TG.AC skin without tumors. In situ hybridization demonstrated that focal expression of the transgene was limited to regions of papilloma development and further localized the expression of the transgene message to the epidermal component of the papillomas, with the strongest signal in the basal epidermoid cells. Cellular proliferation, as indicated by immunohistochemical staining for proliferating-cell nuclear antigen (PCNA), was similarly localized primarily to basal epidermoid cells and, to a lesser extent, stratum spinosum cells in all papillomas analyzed. Cells that stained positively for PCNA were much more common in the papillomas than in the surrounding, normal-appearing skin. The focal nature of papilloma development was also evidenced by protein kinase C activity and hyperplasia after TPA treatment. As early as 18 d after the start of TPA treatment, focal hyperplasias associated with the follicular epidermis were observed in TG.AC but not nontransgenic FVB/N skin; these hyperplasias were assumed to be the precursors of the epidermal papillomas. To explain the development of transgene-expressing tumors from apparently transgene-negative, normal-appearing skin, we hypothesize that the papillomas arise from the clonal expansion of focal areas of epidermal cells that overexpress the transgene. We also propose that the TG.AC line is an excellent model for studying very early events in papillomagenesis.     

"Born from the flank"--discussion concerning "cesarean section" in animals in the Talmud

We determined growth hormone (GH) and insulin-like growth factor I (IGF-I) levels after a 3 h infusion of escalating doses of growth hormone-releasing hormone (GHRH(1-29)) followed by a bolus injection in hypopituitary patients with marked differences in pituitary features at magnetic resonance imaging (MRI) in order to evaluate further the contribution of MRI in the definition of pituitary GH reserve in GH-deficient patients. Twenty-nine patients (mean age 14.5 +/- 4.0 years) were studied. Group I comprised 13 patients: seven with isolated GH deficiency (IGHD) (group Ia) and six with multiple pituitary hormone deficiency (MPHD) (group Ib) who had anterior pituitary hypoplasia, unidentified pituitary stalk and ectopic posterior pituitary at MRI, Group II consisted of eight patients with IGHD and small anterior pituitary/empty sella, while in group III eight had IGHD and normal morphology of the pituitary gland. Growth hormone and IGF-I levels were measured during saline infusion at 08.30-09.00 h, as well as after infusion of GHRH (1-29) at escalating doses for 3h: 0.2 micrograms/kg at 09.00-10.00 h, 0.4 micrograms/kg at 10.00-11.00 h, 0.6 micrograms/kg at 11.00-12.00 h and an intravenous bolus of 2 micrograms/ kg at 12.00 h. In the group I patients, the peak GH response to GHRH(1-29) was delayed (135-180 min) and extremely low (median 2mU/l). In group II it was delayed (135-180 min), high (median 34.8 mU/l) and persistent (median 37.4 mU/l at 185-210 min). In group III the peak response was high (median 30.8 mU/l) and relatively early (75-120 min) but it declined rapidly (median 14.4 mU/l at 185-210 min). In one group I patient, GH response increased to 34.6 mU/l. The mean basal value of IGF-I levels was significantly lower in group I (0.23 +/- 0.05 U/ml) than in groups II (0.39 +/- 0.13U/ ml, p < 0.01) and III (1.54 +/- 0.46 U/ml, p < 0.001) and did not vary significantly during the GHRH(1-29) infusion. The present study demonstrates that the impaired GH response to 3 h of continuous infusion of escalating doses of GHRH(1-29) was strikingly indicative for pituitary stalk abnormality, strengthening the case for use of GHRH in the differential diagnosis of GH deficiency. The low GH response, more severe in MPHD patients, might be dependent on the residual somatotrope cells, while the better response (34.6 mU/l) in the group Ia patients might suggest that prolonged GHRH infusion could help in evaluating the amount of residual GH pituitary tissue. Pituitary GH reserve, given the GH response to GHRH infusion in GH-deficient patients with small anterior pituitary/empty sella, seems to be maintained.     

Basal membrane heparan sulphate proteoglycan expression during wound healing in human skin

Heparan sulphate proteoglycans (HSPGs) are integral components of the basement membrane (BM) in various tissues. HSPGs are important in the assembly and structure of the BM, and their putative functions include regulation of basement membrane permeability, binding of growth factors, and a role in cellular adhesion. In this study the expression of HSPG was examined during wound healing in human skin, using monoclonal antibodies (MAbs) that recognize the HSPG core protein and two different heparan sulphate (HS) epitopes, and the dynamics of HSPG expression were investigated in relation to epidermal cellular proliferation and permeability of the BM. Healing of excisional wounds in healthy volunteers was studied from day 0 up to 1 year. Intact human skin showed strong continuous staining of the dermo-epidermal BM and the vascular BM with all MAbs. Up to day 4 after wounding, staining for HSPG was absent under the ingrowing epidermis, with any of the MAbs, indicating that no complete BM was present. From day 7 onwards, the BM of the neo-epidermis showed positive staining for the HSPG core protein and a low sulphated HS epitope, and after day 14, the staining intensity was similar to normal skin. The staining patterns of these HSPG epitopes were similar to that of laminin. The staining pattern with a MAb against an epitope in the highly sulphated part of HS was found to be distinct from the other BM markers studied. This epitope was absent under the neo-epidermis up to 2 months after wounding. One year after wounding, the epitope was found to be present again. We observed that only in the time period between 2 months and 1 year had the epidermis normalized with respect to the number of cycling cells and the absence of high molecular weight plasma proteins. These findings suggest a correlation between normalization of epidermal proliferation, BM permeability, and regeneration of BM HS. It is proposed that complete BM maturation following skin wounding is a slow process and may account for the epidermal abnormalities that persist for a considerable period of time after wound healing.     

Co-ordination between localized wound-induced Ca2+ signals and pre-wound serum signals is required for proliferation after mechanical injury

The signals which initiate proliferation of endothelial cells after injury are important for selective blood vessel growth during wound healing or tumour growth. Upon mechanically wounding quiescent cells, a transient [Ca2+]i increase was induced in cells at the wound edge. These same cells proliferated 18-24 h post wounding, as measured by bromodeoxyuridine incorporation. The localized Ca2+ signal was required specifically during wounding since blocking Ca2+ influx reduced proliferation by 40-50%. Proliferation also required serum since starvation reduced proliferation by 80%. Serum-starved cells proliferated if briefly primed with serum prior to wounding. The signals derived from serum and [Ca2+]i combined at least additively to induce proliferation. Therefore, serum priming followed by a single, transient Ca2+ signal induced by mechanical injury must occur in a temporally and spatially regulated manner for normal proliferation. Co-ordination between signalling cascades induced by growth factors and release from contact inhibition might be obligatory for localized re-endothelialization after injury.     

Accuracy of histone H3 messenger RNA in situ hybridization for the assessment of cell proliferation in human tissues

Histone H3 mRNA in situ hybridization was compared to a reference method, iododeoxyuridine (IdUrd) immunohistochemistry of tissues labeled in vivo, as a means for assessing the proportion of S-phase cells (labeling index, LI) in oral tumor and normal mucosa. Paraffin sections from 16 patients with oral squamous cell carcinoma were studied. Patients received an IdUrd infusion before the biopsy was taken. Tissue sections were coded before counting the percentages of S-phase cells. A high correlation was found between the results obtained by the two techniques. The average histone H3 and IdUrd LIs of the tumors were 28.5 +/- 2.4% and 29.2 +/- 2.7%, respectively (P = 0.85), with a Spearman correlation coefficient r = 0.95 (P < 0. 0001). The histone H3 LI of the basal layer of normal mucosa was 3.1 +/- 0.8%, whereas the IdUrd LI was 2.7 +/- 0.9% (P = 0.74), with r = 0.78 (P = 0.004). In the suprabasal layers, these parameters were 21. 3 +/- 2.3% and 23.9 +/- 3.2%, respectively (P = 0.56), with r = 0.93 (P < 0.0001). In sections stained for both histone H3 and IdUrd, most cells were double labeled, with very few cells containing only one of the labels. In some specimens, large areas of H3-stained cells did not contain IdUrd-labeled cells, suggesting that during the IdUrd infusion, the precursor did not reach these areas. Two specimens were histone H3 negative. They were also negative when hybridized with beta-actin probe, indicating degradation of mRNAs in these samples. The results of this study demonstrate that the histone H3 mRNA in situ hybridization performed in human formalin-fixed, paraffin-embedded tissues provides the same data as does labeling the tumors in vivo with halogenated pyrimidine.     

Interleukin 2 in the treatment of acute leukemia

Recent immunohistochemical analysis of cell cycle-related proteins such as p27, a cell cycle inhibitory protein, and Ki-67, a proliferation marker, indicated their possible values in predicting the biologic behavior of various human neoplasms. In this study, we performed an immunohistochemical analysis of p27 and Ki-67 in 42 adrenocortical neoplasms (12 adrenocortical carcinomas, 24 adrenocortical adenomas) and 6 normal adrenal glands to evaluate their possible values in diagnosing adrenocortical malignancy and in predicting the biologic behavior of carcinomas. We detected Ki-67 and p27 immunoreactivity in the nuclei of all of our cases, and we observed a significant negative correlation (r = -0.572, P < .001) between the p27 and Ki-67 labeling indexes (LIs). The LIs of p27 and Ki-67 were 61.7+/-2.6 and 0.28+/-0.08 in the normal adrenal cortex and 59.4+/-6.5 and 0.33+/-0.11 in the adenomas, respectively, with no significant differences between the LIs of the adenomas and normal adrenals. The LIs of p27 and Ki-67 in the carcinomas were 48.9+/-7.5 and 630+/-6.21, respectively. The LI of p27 in the carcinomas was significantly lower than that in the adenomas. The LI of Ki-67 in the carcinomas was significantly higher than that in the adenomas (P < .01). Among carcinoma cases, the Ki-67 LI in living cases tended to be lower than that in deceased cases, and the p27 LI in living cases tended to be higher than that in deceased cases, but these differences did not reach statistical significance. These results indicated that decreased p27 protein expression might cause increased cell proliferation in adrenocortical carcinoma cells in combination with other positive and/or negative regulators of the cell cycle. These results also suggested that immunohistochemical analysis of p27 and Ki-67 might be useful in distinguishing between adrenocortical adenoma and carcinoma     

Hexokinase, glucose-6-phosphate dehydrogenase and antioxidant enzymes in diabetic reticulocytes: effects of insulin and vanadate

Growth factors of the transforming growth factor-beta superfamily are involved in cutaneous wound healing. In this study we analyze the expression of the bone morphogenetic protein-6 (BMP-6) gene, a transforming growth factor-beta related gene, in skin wounds. In normal mouse skin high levels of BMP-6 mRNA and protein are expressed by postmitotic keratinocytes of stratified epidermis until day 6 after birth. BMP-6 expression is strongly reduced in adult epidermis with diminished mitotic activity. After skin injury we found large induction of BMP-6-specific RNA and protein in keratinocytes at the wound edge and keratinocytes of the newly formed epithelium as well as in fibroblast shaped cells in the wound bed. BMP-6-specific RNA was induced within 24 h after injury, whereas significant upregulation of BMP-6 on the protein level was detected only 2-3 d after injury. Protein was confined to outermost suprabasal epidermal layers, whereas BMP-6-specific RNA was distributed throughout all epidermal layers including basal keratinocytes and the leading edge of the migrating keratinocytes. We also detected high levels of BMP-6-specific RNA and protein in chronic human wounds of different etiology. In contrast to the overall distribution pattern of BMP-6-specific RNA, the protein was not detected in keratinocytes directly bordering the wound. In order to test the influence of BMP-6 abundance on the progress of wound healing, we analyzed the wound response of transgenic mice overexpressing BMP-6 in the epidermis. In these mice, reepitheliazation of skin wounds was significantly delayed, suggesting that strict spatial and temporal regulation of BMP-6 expression is necessary not only for formation but also for reestablishment of a fully differentiated epidermis.     

Immunity at the surface: homeostatic mechanisms of the skin immune system

The coordinated function of multiple epidermal and dermal cell populations allows the skin immune system to respond rapidly and effectively to a wide variety of insults occurring at the interface of the organism and its environment. Keratinocytes are the first line of defense in the skin immune system, and keratinocyte-derived cytokines are pivotal in mobilizing leukocytes from blood and signaling other cutaneous cells. Cytokine-mediated cellular communication also enables dermal fibroblasts and endothelial cells lining the cutaneous vasculature to participate in immune and inflammatory responses. Skin is an important site for antigen presentation, and both epidermal Langerhans cells and dermal dendritic cells play pivotal roles in T cell-mediated immune responses to antigens encountered in skin. Proinflammatory signaling pathways are necessarily balanced by a variety of regulatory pathways that help maintain the homeostatic functioning of the skin immune system.     

Epidermal cells on stubs used for detection of GSR with SEM-EDX: analysis of DNA polymorphisms

DNA from epidermal cells attached to the adhesive tape of stubs employed to collect and identify gunshot residue (GSR) with scanning electron microscope (SEM) was extracted, amplified with PCR and typed. The method allowed identification of specimens when attribution to a definite person was uncertain. These results also suggest that adhesive tape could be used as a non invasive method for obtaining biological material suitable for DNA analysis from the skin surface.     

MIB-1 labeling indices in benign, aggressive, and malignant meningiomas: a study of 90 tumors

Predicting tumor behavior in meningiomas based on histology alone has been problematic. This study retrospectively compares histology and MIB-1 (cell proliferation marker) labeling indices (LI) in benign, aggressive, and malignant meningiomas. Six histological features, including mitoses, necrosis, loss of pattern, hypervascularity/hemosiderin deposition, prominent nucleoli, and nuclear pleomorphism, were compared in 90 meningiomas (Fisher's exact test). Tumors with two or more of the above features were designated as aggressive meningiomas. Malignant meningiomas were characterized by brain invasion or metastasis. The MIB-1 LIs (% positive tumor cell nuclei) were compared between the three groups (Kruskal-Wallis test, Wilcoxon two-sample test). Of the benign meningiomas (n=37; mean age, 54 years), 41% had one of the six histological features, with nuclear pleomorphism (n=10) being the most frequent. The aggressive tumors (n=29; mean age, 61 years) were characterized by nuclear pleomorphism (n=28), mitoses (n=20), necrosis (n=16), loss of pattern (n=16), prominent nucleoli (n=6), and hypervascularity/hemosiderin deposition (n=5). Malignant tumors (n=24; mean age, 59 years) were characterized by nuclear pleomorphism (n=22), mitoses (n=21), loss of pattern (n=21), necrosis (n=21), nucleoli (n=17), and hypervascularity/hemosiderin deposition (n=3). Significant differences were found between the aggressive and malignant groups with regard to loss of pattern, necrosis, and nucleoli (P=.0043, .011, and .00029, respectively). Mean MIB-1 LIs for the benign, aggressive, and malignant groups were 1.0% (range, 0 to 5.5%),5.5% (range, 0.1 to 32.5%), and 12.0% (range, 0.3 to 32.5%), respectively. Differences in the mean MIB-1 LI between groups were statistically significant, with P values of <.0001 (benign v aggressive) and .0012 (aggressive v malignant). Mean MIB-1 LIs for recurrent versus nonrecurrent tumors were 7.1% (range, 0 to 32.5%) versus 3.8% (range, 0 to 20.9%) (P=.32). The mean MIB-1 LI for patients who were alive with or without tumor was 6.2% (range, 0 to 32.5%) versus a mean MIB-1 LI of 14.2% (range, 2.8% to 32.5%) for patients who died of or with tumor (P=.0013). In conclusion, (1) There is a statistically significant difference in the increasing MIB-1 LI means between benign, aggressive, and malignant meningiomas and between patients who were alive versus those who died; (2) there is some overlap in MIB-1 LI ranges between groups, which warrants caution in interpreting an individual MIB-1 LI in a given tumor.     

Tri-iodothyronine regulates the production of interleukin-6 and interleukin-8 in human bone marrow stromal and osteoblast-like cells

Exposure to irritants may cause chronic irritant contact dermatitis (ICD), characterized by irregular epidermal thickening and a predominantly dermal mononuclear cell infiltrate. The mechanisms involved, and why only certain individuals are affected, are not clearly understood. Different irritants may trigger different cellular and molecular interactions between resident skin cells and recruited inflammatory cells. In some individuals these interactions may become self-perpetuating resulting in persistent inflammation in the absence of continued exposure. This study examined Langerhans cell (LC) density in clinically normal skin of 46 patients with chronic ICD and 10 healthy individuals, and compared the action of the two irritants nonanoic acid (NA) and sodium lauryl sulphate (SLS) on the LCs and keratinocytes of clinically normal skin in patients with chronic ICD. There was a higher number of LCs/mm basement membrane in patients compared with controls, although there was no difference in the number of dendrites/LC nor in dendrite length. SLS induced keratinocyte proliferation after 48 h exposure, had no effect on LC number or distribution, and induced keratinocyte apoptosis after 24 and 48 h exposure. In contrast, NA decreased keratinocyte proliferation after 24 h exposure but this returned to basal levels after 48 h, and induced epidermal cell apoptosis after only 6 h exposure. NA dramatically decreased LC number after 24 and 48 h exposure, which was accompanied by basal redistribution and decreased dendrite length. Most significantly, NA induced apoptosis in over half of the LCs present after 24 and 48 h exposure.     

Analysis of proliferative activity of the parathyroid glands using proliferating cell nuclear antigen in patients with hyperparathyroidism

To elucidate the cellular proliferative kinetics of the parathyroidal gland in patients with hyperparathyroidism, we investigated the expression of proliferating cell nuclear antigen (PCNA) in parathyroidal tissues using an immunohistochemical procedure. The PCNA labeling index (LI; maximum LI, maximal stained area; average LI, evenly distributed stained area) indicating cellular proliferative activity was defined as the number of PCNA-positive cells per 1000 parathyroid cells in the region of interest. We used these indexes to compare and investigate the proliferative activity of parathyroid cells under various conditions. The specimens used for the study were 42 parathyroid glands from 21 patients with primary hyperparathyroidism (19 cases of adenoma and 2 cases of primary hyperplasia due to multiple endocrine neoplasia type 1) and 129 parathyroid glands from 32 patients with secondary hyperparathyroidism. An additional 40 parathyroid glands resected during thyroid surgery of 30 normocalcemic patients were used as normal controls. In normally functioning parathyroids, a small number of cells in the growth phase were found. In primary hyperparathyroidism, proliferative activity was highest in the adenoma followed by primary hyperplasia. In contrast, the PCNA LIs showed a low value in the normal rim of the adenoma and normal glands resected as biopsy specimens from adenoma patients. We, therefore, assumed that proliferative activity was suppressed in these cells compared with that in normally functioning glands. In secondary hyperparathyroidism, when the cell component of the parathyroid tissues was divided into five types, PCNA immunoreactivity was lowest in the dark chief cells. Proliferative activity in cells of the oxyphil series was the same or higher than that in the clear chief cells or vacuolated chief cells. When classified according to the structure of the parathyroid glands, cell proliferation was significantly higher in the nodular type than in the diffuse type (maximum LI, 176 +/- 231 vs. 38.3 +/- 55.7; average LI, 120 +/- 188 vs. 24.8 +/- 43.5; mean +/- SD; P < 0.001). More PCNA-immunoreactive cells were found in autotransplanted glands with recurrence than in glands resected during the initial surgery. To summarize the PCNA expression classified according to the pathological types of hyperparathyroidism, the PCNA LIs were highest in secondary hyperplasia (maximum LI, 144 +/- 212; average LI, 96.0 +/- 169) and adenoma (maximum LI, 102 +/- 81.7; average LI, 67.5 +/- 67.7), followed by primary hyperplasia (maximum LI, 25.0 +/- 25.4; average LI, 19.2 +/- 22.2) and normal glands (maximum LI, 13.6 +/- 23.9; average LI, 4.40 +/- 8.90). These findings suggest that the cellular proliferative kinetics of the parathyroid gland differ depending on the type of hyperparathyroidism, glandular structure, and cell components. As the detection method of intranuclear expression of PCNA in cells is too sensitive, we should be careful not to overestimate the number of cells in the proliferative cycle. However, these results could not have been obtained using a conventional method such as DNA analysis by flow cytometry.