Epithelium Of Man Research Articles

The number of the intraepithelial T cells correlate with the proliferation index in human bulbourethral gland epithelium

BackgroundOur study has immunohistochemically examined T cells localization and number as well as proliferative activity level for the bulbourethral gland epithelium in men of different ages, using monoclonal antibodies against CD45RO and proliferating cell nuclear antigen (PCNA). ResultsWe have found that the T cells have been localized mainly in excretory ducts epithelium of the glands in any age group, meanwhile their relative number varies with age. The excretory ducts epithelium has shown a high proliferative activity when in acini the PCNA index has been low. Postnatal dynamics of the epithelium proliferative activity positively correlates with age-related density fluctuations in lymphocytic infiltration of the glands. ConclusionsWe consider that intraepithelial T cells may contribute to the regulation of epithelial cells proliferation in the bulbourethral glands.

Saw palmetto herbal blend causes involution of the prostatic epithelium in men with symptomatic benign prostatic hyperplasia

Focus on Alternative and Complementary TherapiesVolume 5, Issue 4 p. 271-272 Saw palmetto herbal blend causes involution of the prostatic epithelium in men with symptomatic benign prostatic hyperplasia First published: 14 June 2010 https://doi.org/10.1111/j.2042-7166.2000.tb02598.xRead the full textAbout ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume5, Issue4December 2000Pages 271-272 RelatedInformation

Differences in replication kinetics and cell tropism between neurovirulent and non-neurovirulent EHV1 strains during the acute phase of infection in horses

Equine herpesvirus 1 (EHV1) replicates in the respiratory tract of horses, after which infected leukocytes transport virus throughout the body, resulting in abortion or nervous system disorders. Two EHV1 strains circulate in the field: neurovirulent and non-neurovirulent. To investigate differences in replication in the upper respiratory tract (URT), an experimental inoculation study in ponies was performed with both strains. Two groups of six ponies, were inoculated intranasally with 106.5 TCID50 of either strain. Clinical signs, nasal shedding and viremia were evaluated. At early time points post-inoculation (pi), one pony of each group was euthanized. Tissues were collected for titration and immunostainings. Number and size of EHV1-induced plaques were calculated, and individual EHV1-infected cells were quantified and characterized. Inoculation with either strain resulted in nasal shedding and replication in several tissues of the URT. Both strains replicated in a plaquewise manner in epithelium of the nasal mucosa, but replication in epithelium of the nasopharynx was largely limited to non-neurovirulent EHV1. Plaques were never able to cross the basement membrane, but individual infected cells were noticed in the connective tissue of all examined tissues for both strains. The total number of these cells however, was 3–7 times lower with non-neurovirulent EHV1 compared to neurovirulent EHV1. CD172a+ cells and CD5+ lymphocytes were important target cells for both strains. Interestingly, in lymph nodes, B-lymphocytes were also important target cells for EHV1, irrespective of the strain. Viremia was detected very early pi and infected cells were mainly CD172a+ for both strains. In summary, these results are valuable for understanding EHV1 pathogenesis at the port of entry, the URT.

Excretion of immunochemically assayable FSH and LH and quantitative analysis of germinal epithelium in man.

Zusammenfassung Bei 28 sub- oder infertilen Mannern wurden FSH und LH im unkonzentrierten Urin mit neuen immunochemischen Testen bestimmt und zusatzlich beidseitige Hodenbiopsien durchgefuhrt. Patienten mit deutlich erhohter FSH-Ausscheidung hatten entweder ein Sertolizellsyndrom oder einen Spermatogenesestop vor oder ab dem Stadium der Spermatozyten; dagegen wurden ahnlich schwere Hodenschaden bei Patienten mit normaler oder nur masig erhohter FSH-Ausscheidung nicht gefunden. Bei 12 Patienten wurden in beiden Hoden in jeweils 50 Tubuli alle Keimzellen gezahlt. Der mittlere Tubulusdurch-messer und die mittlere Spermatiden- und Spermatozoenzahl pro Tubulus waren in der Gruppe mit normaler FSH-Ausscheidung signifikant hoher als in der hypergonadotropen Patientengruppe. Die Ergebnisse belegen eine inverse Korrelation zwischen Spermatogenese und FSH-Spiegeln beim Mann und sprechen dafur, das dieser Ruckkopplungs-mechanismus in einem spaten Spermatogenesestadium ansetzt. Die Bedeutung der FSH-und LH-Bestimmung fur die Prognose bei Patienten mit Azoospermie oder schwerer Oligozoospermie wird diskutiert.

Hyperactivation of early steps of spermatogenesis compromises meiotic insufficiency in men with hypergonadotropism. A possible quantitative assay for high FSH/low testosterone availabilities

It has been shown previously that blood plasma elevation of FSH is associated with an impaired function of the seminiferous tubules. In the study presented here quantitative analysis of the seminiferous epithelium was performed in testicular biopsies of men with qualitatively complete spermatogenesis and hypergonadotropism (HG group, n = 6) or normogonadotropism (NG group, n = 9). Hormonal determinations were performed also in eight men with Sertoli cells only (SCO group). Plasma levels of gonadotropins found in HG were comparable with those found in SCO, while mean plasma testosterone levels in these patients were significantly lower than in SCO or NG. A significant decrease in the mean number of spermatids was present in HG, while the mean numbers of B spermatogonia (0.6 +/- 0.2) and preleptotene spermatocytes (0.6 +/- 0.1) were significantly elevated in comparison with NG (0.4 +/- 0.1 and 0.3 +/- 0.2, respectively). In all men with HG a GnRH test (100 micrograms i.v.) was performed and the relative increase of plasma FSH (maximum/basal level) correlated positively with the number of A-pale (r = 0.85, P less than 0.05) and B spermatogonia (r = 0.81, P less than 0.05). In NG group basal levels of FSH correlated with A-pale (r = 0.90, P less than 0.001) and B spermatogonia (r = 0.59). It seems that FSH plays a role to maintain the number and the differentiation rate of spermatogonia in men and is responsible for the hyperactivation of spermatogonia when secreted in excess. Hyperactivation of spermatogonia probably develops to compensate quantitative decrease in gamete production.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential gene expression in normal prostate epithelium of men with and without prostate cancer

5142 Background: Several solid tumors are associated with molecular changes in adjacent, histologically normal cells, the so-called “field effect”. This field effect may predispose the normal cells to the development of frank malignancy. We sought to determine if normal epithelium from prostates harboring prostatic adenocarcinoma harbor changes in gene expression suggestive of pre- malignancy or field effect. Methods: Prostate needle biopsies from 15 men with high grade (Gleason 8–10) prostate cancer and 15 age- and BMI-matched controls were identified from a pool of biopsies collected from >500 men since 2003. Normal epithelia from each patient were isolated via laser capture microdissection (LCM) of fresh frozen biopsy tissue with review by a pathologist. RNA was isolated, amplified, then utilized for microarray analysis using the Agilent Human 4x44K array platform. The data were analyzed by paired two-sample T- test using Significance Analysis of Microarrays (SAM). Quantitative PCR (qPCR) was also used to determine the expression of various genes of interest identified by microarray analysis. Results: One control patient was excluded for prostate cancer on repeat biopsy. The remaining 14 control and 15 cancer samples were included in the final analysis. Microarray analysis revealed that these two groups had very similar patterns of gene expression overall. SAM analysis found significant q values (q <1%) in 2 genes previously associated with prostate cancer, namely PSMA and SSTR1. We examined other prostate cancer-associated genes by qPCR and found significant differential expression changes in ERG, HOXC4, HOXC5 and MME, although other cancer markers (HPN, AMACR, FASN) were not different between the two groups. Interestingly, the elevated ERG expression in the normal epithelia adjacent to prostate cancer did not appear to be associated with the TMPRSS2:ERG fusion with the exception of one patient. Conclusions: Overall gene expression profiles between normal prostatic epithelia of patients with and without prostate cancer are very similar. However, several of the differentially expressed genes found in this study have been implicated in prostate cancer progression and prognosis in prior studies, and thus may represent the earliest events in prostate carcinogenesis. No significant financial relationships to disclose.

Cytologic atypia in a 53-year-old man with finasteride-induced gynecomastia.

Finasteride has been associated with the development of gynecomastia. Although cytoplasmic vacuolization has been noted in prostatic epithelium in men taking this drug, we found no documentation of the cytologic changes in finasteride-associated gynecomastia. We present the case of a 53-year-old man who developed unilateral gynecomastia following finasteride therapy for alopecia. A fine-needle aspiration biopsy of the mass was diagnosed as adenocarcinoma on the basis of nuclear atypia and particularly because of cytoplasmic vacuolization. Subsequent excisional biopsy revealed benign gynecomastia with no evidence of malignant change. The ductal epithelium did exhibit cytoplasmic vacuolization similar to that described in the prostate following finasteride therapy. We believe this is the first reported case documenting the cytologic changes seen in gynecomastia secondary to finasteride therapy. Cytoplasmic vacuolization in this setting should not be considered evidence of malignancy in men with gynecomastia. As with gynecomastia in general, extreme caution should be used before rendering a cytologic diagnosis of malignancy.

Saw palmetto herbal blend causes involution of the prostatic epithelium in men with symptomatic benign prostatic hyperplasia

Saw palmetto herbal blend causes involution of the prostatic epithelium in men with symptomatic benign prostatic hyperplasia

Interspecies variations in oral epithelial cytokeratin expression.

The aim of this study was to determine the degree to which the epidermis and oral epithelium of species other than man express cytokeratin (CK) intermediate filaments, which are markers of epithelial differentiation. Fixed, wax-embedded samples of skin, buccal mucosa and gingiva from rhesus monkey, marmoset, cow, sheep, pig, ferret, hamster, axolotl and trout were tested for CK expression using a panel of antihuman CK antibodies and an immunoperoxidase procedure. Human skin and oral mucosa were also stained to act as positive control. The results showed that antihuman CK antibodies stained animal tissues, but the patterns of staining were not always identical to the established human CK profile. Of particular interest was the expression of CK18, typically only detected in 'simple' epithelium in man, in bovine, ferret and hamster stratified epithelium from different sites. However, there was evidence of variable anti-CK antibody cross-reactivity, both as a result of intrinsic variations in CK polypeptide structure and as artifacts of fixation. We conclude that some CK are conserved between species, but that biological variables, for example local functional requirements, and technical factors affect the results. These considerations need to be borne in mind in animal studies of epithelial differentiation employing CK immunohistochemistry. Biochemical characterisation is ultimately necessary to determine specific differences between human and animal CK.

Absence of Cyclic Adenosine 3′:5′ Monophosphate Responsive Element Modulator Expression at the Spermatocyte Arrest Stage

Objective: To test the hypotheses that variations in the expression of adenosine 3′:5′ monophosphate (cAMP) responsive element modulator are found in human seminiferous epithelium in men with impaired testicular function and subsequent infertility and that variations in apoptosis frequency are associated with differential cAMP responsive element modulator expression in male infertility states. Design: Standard immunohistochemical staining using a rabbit polyclonal antibody against the τ isoform of the cAMP responsive element modulator protein was performed on 5-μM sections of Bouin’s fixed, paraffin-embedded testicular tissue obtained from azoospermic or severely oligozoospermic men for routine clinical purposes. Histologic diagnosis was confirmed with computerized image analysis of Feulgen-stained sections. Setting: Tertiary male infertility referral center at a medical school. Patient(s): Forty-eight testis biopsies were performed in 38 azoospermic or severely oligozoospermic males. Intervention(s): Rabbit polyclonal cAMP responsive element modulator τ antibody was applied to the paraffin-embedded testis sections. Main Outcome Measure(s): Testis immunoreactivity to polyclonal cAMP responsive element modulator τ antibody and apoptotic indices. Result(s): Although cAMP responsive element modulator immunoreactivity was present in the round spermatid stage of meiosis in testis biopsy specimens showing normal spermatogenesis, spermatid maturation arrest, and hypospermatogenesis, there was complete absence of expression in biopsy specimens from patients with Sertoli cell only and spermatocyte maturation arrest states. In addition, significantly increased apoptotic indices were observed in the spermatocyte maturation arrest state in comparison with normal spermatogenesis and Sertoli cell only pattern. Conclusion(s): These data suggest that cAMP responsive element modulator may be important for spermatid development and a stage-specific regulator of human spermatogenesis. Absence of cAMP responsive element modulator may be a cause of testicular failure in various types of male infertility.

Relationship between changes in prostate-specific antigen and the percent of prostatic epithelium in men with benign prostatic hyperplasia

Objectives Pretreatment knowledge of prostate gland histology would allow a more scientifically based selection of medical therapy for men with benign prostatic hyperplasia (BPH) and may increase the effectiveness of the pharmacologic agents available. Changes in prostate-specific antigen (PSA), or PSA velocity, may reflect prostatic epithelial growth in BPH. Our objective was to determine if PSA velocity prior to diagnosis correlated with the relative amount of epithelium in BPH tissue. Methods We evaluated 39 men with BPH who had serial PSA determinations (mean, 5.4) on frozen sera from 2.3 to 25.1 years before diagnosis, and archival material from simple prostatectomy available for pathologic evaluation. We used an immunoenzymatic staining technique for PSA to bind prostatic epithelium selectively so that color differences in the stained tissue sections could be used to quantify stroma, epithelium, and glandular lumina. Results The average percentage of epithelium (%E) was 1 2.4 and the average stroma-epithelial ratio (SER) was 6.6. The correlation of PSA velocity for the three visits nearest to prostatectomy (n = 32) versus %E and SER was significant ( P = 0.003 for both). The PSA value nearest to prostatectomy (n = 39) was directly correlated with %E and SER ( P = 0.0001 and P = 0.001, respectively). Conclusions These data suggest that PSA and PSA velocity are directly related to the histologic makeup of the prostate in men with BPH. Thus, pretreatment evaluation of PSA could be useful as part of an evaluation to direct BPH therapy.

Progesterone-associated endometrial protein--a constitutive marker of human erythroid precursors

Progesterone-associated endometrial protein (PAEP/PP14) is a 28-kD glycoprotein with sequence homology to beta-lactoglobulins containing a retinol-binding motif. PAEP/PP14 is present at nanomolar concentrations in human serum. It is produced by secretory and decidualized endometrium in women and by seminal vesicle epithelium in men. We report here that PAEP mRNA is constitutively expressed in normal hematopoietic tissue. Western immunoblotting of bone marrow cells with rabbit antibodies to PAEP gave a band at 28 kD, and immunocytochemical staining with monoclonal antibodies localized PAEP into the cytoplasm of erythroid precursors representing different stages of the normoblast series. PAEP was not detected in mature red blood cells, platelets, or in cells of the myeloid lineage. Untreated K562 leukemia cells did not contain PAEP, whereas treatment of the cells with tetradecanoylphorbol acetate (TPA) induced strong expression of PAEP mRNA and synthesis of the intact protein that was found both in the cytoplasm of the differentiating cells and in the supernatant of TPA-treated cultures. These findings add a new member to the growing family of genes that are constitutively expressed both in the reproductive tract and in the hematopoietic system.

Progesterone-Associated Endometrial Protein—A Constitutive Marker of Human Erythroid Precursors

Progesterone-associated endometrial protein (PAEP/PP14) is a 28-kD glycoprotein with sequence homology to beta-lactoglobulins containing a retinol-binding motif. PAEP/PP14 is present at nanomolar concentrations in human serum. It is produced by secretory and decidualized endometrium in women and by seminal vesicle epithelium in men. We report here that PAEP mRNA is constitutively expressed in normal hematopoietic tissue. Western immunoblotting of bone marrow cells with rabbit antibodies to PAEP gave a band at 28 kD, and immunocytochemical staining with monoclonal antibodies localized PAEP into the cytoplasm of erythroid precursors representing different stages of the normoblast series. PAEP was not detected in mature red blood cells, platelets, or in cells of the myeloid lineage. Untreated K562 leukemia cells did not contain PAEP, whereas treatment of the cells with tetradecanoylphorbol acetate (TPA) induced strong expression of PAEP mRNA and synthesis of the intact protein that was found both in the cytoplasm of the differentiating cells and in the supernatant of TPA-treated cultures. These findings add a new member to the growing family of genes that are constitutively expressed both in the reproductive tract and in the hematopoietic system.

Molecular biology of human male infertility: links with aging, mitochondrial genetics, and oxidative stress?

Molecular biology of human male infertility: links with aging, mitochondrial genetics, and oxidative stress?

Laser Treatment of Genital Human Papillomavirus Infections in the Male Patient

Thorough examination of the lower anogenital epithelium of promiscuous men and their partners (either male or female) may be useful to diagnose and, if appropriate, treat those who are likely to perpetuate the HPV epidemics and increase the potential risk for cervical carcinogenesis. CO2 laser ablation is a highly attractive means to treat HPV-related disease of the anogenital epithelium in men. The Nd:YAG laser also has some specific applications in the treatment of large, relatively vascular lesions. A stable sexual relationship or consistent use of condoms in polygamous sexual practices is probably the most meaningful means of controlling the sexual transmission of HPV.

Changes in surface area and number of Leydig cells in relation to the 6 stages of the cycle of the human seminiferous epithelium.

In order to evaluate the occurrence of a Leydig cell cycle related to the cycle of the seminiferous epithelium in man, the numbers of peritubular Leydig cells and surface area of these cells along 1 mm of tubular basement membrane at each stage of the cycle were calculated on histological sections of young adult testes. The Leydig cells that were located separated from the tubules (perivascular Leydig cells) were also classified according to the stage of the cycle shown by the nearest seminiferous tubule; the surface area and number of these cells were also calculated. The total surface area and numbers of Leydig cells (peritubular plus perivascular) along 1 mm of tubular basement membrane did not change during the cycle of the seminiferous epithelium. Both the surface area and the numbers of peritubular Leydig cells were greater in stages I and II of the cycle, when spermatozoa are released; they decreased in stages III and IV and increased again in stages V and VI, whereas the contrary occurred in perivascular Leydig cells. The average surface area of each Leydig cell type remained constant throughout the stages of the cycle.

Immunohistochemical detection of ras oncogene p21 product in benign and malignant mammary tissue in man.

The monoclonal antibody RAP-5 generated against a synthetic peptide corresponding to amino acid positions 10-17 of the ras p21 protein was used in an immunohistochemical study of the expression of ras in normal, benign, and malignant breast epithelium in man. The staining intensity and intracellular distribution of RAP-5 was similar in the three epithelial populations and extended to other tissue elements including myoepithelial cells, smooth muscle, myelin, capillary endothelium, and stromal fibroblasts, as well as sebaceous glands and sweat glands overlying the breast. These results suggest that RAP-5 recognises a normal cellular component, the expression of which is not more enhanced in hyperplastic or neoplastic conditions. The detection of mutant forms of p21 exclusively expressed in malignant tumours requires that alternative reagents be developed.

Nature of "basal" and "reserve" cells in oviductal and cervical epithelium in man.

The epithelium of the human fallopian tube (oviduct) and cervix were studied by histological, immunohistological, and ultrastructural methods with a view to establishing the nature of the so called "basal" and "reserve" cells. The results indicated that the "basal" cells of the oviductal epithelia were T lymphocytes, with a predominance of T cytotoxic and suppressor cells. A more heterogeneous inflammatory cell population was present in cervical epithelium, although once again T cytotoxic and suppressor cells were the most numerous subtype. The intraepithelial inflammatory cells were quite distinct from the cells commonly referred to as "reserve" cells (reserve cell hyperplasia), which have epithelial characteristics. The origin of the "reserve" cells is unclear, but they seem to arise within the epithelium. They probably represent an early sign of squamous metaplasia. The lymphoid tissue of fallopian tube and endocervix shows similarities with that of the endometrium and mucosal associated lymphoid tissue in general.

Polymeric IgA is complexed with secretory component (SC) on the surface of human intestinal epithelial cells.

Viable suspensions of columnar cells were obtained from the surface and outer crypt epithelium of human colon mucosa by a combined treatment with citrate and EDTA solutions and mechanical disruption, but without the use of enzymes. A substantial fraction of the isolated cells contained free SC and secretory IgA in a cytoplasmic distribution that corresponded to previously reported immunohistochemical and immunoelectron-microscopical results obtained with tissue sections. On their surface the same cells were shown to bear SC complexed with J-chain-containing polymeric IgA, whereas only occasional traces of free SC were found. IgM was detected in the surface patches which contained the largest concentrations of SC and IgA. These findings demonstrate that in SC-producing epithelial cells SC molecules become exposed on the plasma membrane, thereby being able to bind specifically J-chain-containing IgA and IgM present in the tissue fluid. Such adsorptive complexing is probably a prerequisite for the selective pinocytotic transport of these two Ig classes through glandular epithelium in man.

Keratinizing Potential of Human Crevicular Epithelium

T H E MORPHOLOGY of the crevicular epithelium in man differs from that of gingival epithelium. Gingival epi­ thelium is composed of stratified squamous epithelium normally exhibiting a keratinized or a parakeratinized surface, 1 , 2 while crevicular epithelium consists of a thin layer (5-15 cells) of nonkeratinized squamous epithe­ lium. 2 Human crevicular epithelium does not possess either a stratum granulosum or a stratum corneum, although these layers have been observed in the cre­ vicular epithelium of other species including the rat and hamster. 3 , 4 Since morphologic appearance is a major means of characterizing the state of keratinization of the epithelium, it is not surprising that most theories of keratin formation are based on the sequence of events seen in histologic and electron microscopic prepara­ tions. The nonkeratinizing nature of human crevicular epithelium has been reported by both light and electron microscopic investigations. 3 , 7 McHugh , 3 using polariz­ ing microscopy as well as histochemical analyses for the distribution of sulphydryl and disulphides at the surface of epithelium, concluded that crevicular epithelium in man and monkey is not keratinized. In a recent ultrastructural study of human gingiva, Takarada, et a l . , 8 did not observe any discernible keratin pattern in the crevicular epithelium and the coronal aspect of pocket epithelium. However, some of their specimens showed epithelia with one or more of the features associated with the process of keratinization, i.e., keratohyaline granules, birefringence of the spinous cells, membrane coating granules, and thickening of the plasma mem­ brane. Although the exact role of keratohyaline gran­ ules has not been well established, recent autoradi­ ographic and biochemical data strongly suggest that they are important precursors in the formation of the kerat in . 9 , 1 0 More recently, Listgarten provided further evidence that the human crevicular epithelium has a tendency towards keratinization. His observations were also supported by the appearance of keratohyaline and membrane coating granules. Absence of keratinization has been related to the hypothesis that nonfunctioning lining epithelium does not keratinize in the absence of functional stimuli. 1 1 However, conversion of a nonkeratinized epit' elium to a keratinized epithelium may not be related to direct physical stimulation of the epithelium, 1 2 but rather de­ pend on the environment in which it exists. Some recent studies notably those of Innes, 1 3 B a n o c z y 1 4 and Caffesse and Karring 1 5 have indicated that environ­ mental changes may indeed alter the keratinization potential of crevicular epithelium. Since the nonkera­ tinized nature of the crevicular epithelium has been considered as the weak link in the gingival unit, it may serve as the site of the primary gingival les ion. 1 6 2 4 Clinicians, therefore, have sought therapeutic meas­ ures (such as intrasulcular brushing) 2 5 to enhance the keratinization of the crevicular epithelium, thereby in­ creasing its effectiveness as a protective barrier. O n the other hand, recent embryologic studies on epithelialmesenchymal interactions 2 6 3 0 and grafting 3 1 3 3 experi­ ments have suggested that keratinization of this tissue may be limited by the dermal specificity of the underly­ ing tissue. 4 Thus, therapeutic measures de­ signed to enhance keratinization would prove to be unsuccessful. The popularity of the concept of connective tissue as determinant may be partly due to the difficulty of designing and assessing experiments to demonstrate the opposite. In any event, proving that tissue determines epithelial morphology does not altogether discount the possibility that epithelium also determines tissue morphology, or at least, its own mor­ phology. It is this possibility that has led some workers to postulate that mutual determination or an interac­ tion between both tissue and epithelium may control dermal specificity. 3 5 3 7 For example, A l vares and Myer 3 8 showed that there were differences between different types of orthokeratinized epithelia, such as that from rat cheek and rat palate, almost as great as those between keratinized and nonkeratinized epithelia. This reinforces Weinmann's 3 9 suggestion that the process of keratinization might be considered as a spectrum, varying in small steps between the extremes of orthokeratinization and nonkeratinization, rather than an all-or-none process. In order to further elucidate the keratinization po­ tential of human crevicular epithelium, we undertook a histologic study of this epithelium when its local envi­ ronment was drastically altered.