Subepithelial Connective Tissue Layer Research Articles

Ciliated foregut cysts involving the hepatopancreaticobiliary system: a clinicopathological evaluation with focus on atypical features.

Foregut cystic malformations are rare developmental abnormalities, which may involve the hepatopancreaticobiliary tract (HPBT). These cysts are composed of inner ciliated epithelium; subepithelial connective tissue layer; smooth muscle layer; and an outer fibrous layer. While radiopathologic findings are often diagnostic, atypical location and histologic features can pose a diagnostic challenge. We aimed to study ciliated foregut cysts (CFCs) in the HPBT, assess their clinicopathological features with a focus on atypical features. We collected cases of CFCs involving the HPBT from three large academic medical centres. H&E-stained slides and immunohistochemical stains (where available) were reviewed for each case. Relevant demographic, clinical and pathological information was collected from the medical records. 21 cases were identified. The median age was 53 years (range, 3-78 years). 17 cysts were identified within the liver (segment 4 was the most common location, n=10) and 4 in the pancreas. Cysts were mostly identified incidentally (n=13), abdominal pain was a common symptom (n=5). Cyst size ranged from 0.7 to 17.0 cm (median, 2.5 cm). Radiological findings were available in 17 cases. Cilia were identified in all cases. 19 of 21 cases demonstrated the presence of a smooth muscle layer (thickness, <0.1 mm to 3.0 mm). Three cases showed gastric metaplasia, while one case revealed additional low-grade dysplasia, with features similar to intraductal papillary neoplasm of the bile duct. We highlight clinicopathological features of CFCs in the HPBT. The histomorphology is usually straightforward; however, unusual location and atypical features can pose a diagnostic challenge.

Gross and Histomorphological Assessment of the Oropharynx and Tongue of the Guinea Fowl (Numida Meleagris)

The study investigated the morphology of the oropharynx and tongue of the guinea fowl using gross anatomical and histological techniques. The results showed that the mouth and pharynx of the guinea fowl lacked a definite line of demarcation, and so formed a common oropharyngeal cavity. The roof of the oropharynx was formed by the hard palate and the choana. The hard palate was characterized by a broad v-shaped rostral mucosal swelling, a median palatine ridge that bifurcated caudally into left and right lateral palatine ridges, and para-median rows of caudally pointed conical papillae. The tongue of the guinea fowl was located on the floor of the oropharynx, but did not extend to the full limits of the lower beak. The caudal and rostral parts of the tongue were demarcated by a v-shaped row of papillae, the papillary crest. Histologically, the dorsal surface of the tongue was lined by a non-keratinized stratified squamous epithelium that contained intraepithelial taste buds, while the lining on the ventral surface of the tongue was a keratinized stratified squamous epithelium. Other features include a wide sub-epithelial connective tissue layer containing lingual glands, and a core of striated muscles. The lingual glands of the guinea fowl consisted of tubular secretory units made up of mucus-secreting cells. These findings may be important in nutritional and medical management of guinea fowls especially under the intensive system of production. Furthermore, our study has provided a foundation for recognition of pathology in the oropharynx and tongue of the guinea fowl.

Effects of age on growth and development of vagina in ISA Brown chickens

Structure and postnatal development of vagina in 21 ISA brown chickens was studied at three, 23 and 46 weeks of age. At 3 weeks of age the vagina was narrower and thicker then the uterus. The undifferentiated wall of vagina consisted of low primary mucosal folds lined by simple columnar epithelium to a pseudostratified ciliated columnar epithelium and a connective tissue layer underneath. At three weeks of age, scattered smooth muscle fibres were in the subepithelial connective tissue layer. Rapid structural changes occurred at 23 weeks of age in the adult bird, mucosal folds were narrowed and tongue-shaped. Lamina propia was devoid of glands and contained lymphocytes. Tunica muscularis was well developed at 23 and 46 weeks.DOI: http://dx.doi.org/10.3329/bvet.v28i2.10676Bangl. vet. 2011. Vol. 28, No. 2, 75 – 79

A study on paranal sinus micromorphometrical parameters in dogs of different ages

This study determines the micromorphometric parameters of the main structural elements of the paranal sinus in male (n = 20) and female (n = 8) mongrel dogs of different ages. Pieces of about 1 cm3 were obtained from different parts of the organ and put in 10% neutral formalin. The tissue samples were further used for the preparation of paraffin sections that were stained with hematoxylin-eosin for light microscopy measurements. In the sinus wall, the thickness of the epithelium was measured, as was that of the subepithelial and subglandular connective tissue layers, the zona with the apocrine glands, and the entire sinus wall. The outer and inner diameters of the apocrine tubular glands and the height and number of glandular epithelial cells in the apocrine glands were also measured. Statistical data processing was done using Data Analysis tool and t-test by means of the StatMost for Windows software. For the period from the 1st month to the 2nd year, the thickness of the epithelial layer of the sinus wall remained almost identical (from 40.83 ± 9.37 µm during the 1st month to 47.79 ± 3.67 µm in the 2nd year). After the 2nd year, the thickness of the epithelial layer decreased. In the 8th year its thickness reached 35.72 ± 5.89 µm and in the 12th year it was 28.92 ± 6.53 µm. We measured the thickness of the subepithelial and subglandular connective tissue layers of the wall of the sinus, forming the organ's stroma. It was found that the thickness of these layers increased 3-fold for the period from the 1st month to the 12th year. Their thickness increased most intensively until the 5th month, followed by the period from the 5th month to the 2nd year, then from the 2nd to the 8th year, and changed the least up to the 12th year. Therefore, the increase in the thickness of the sinus wall (without its excretory duct) with age was due to the increase of the thickness of the subepithelial and subglandular connective tissue layers in particular. The results of the present study demonstrate that the period featuring the most active weight increase and growth of sinus macromorphometric parameters coincided with the period of increase in the number of cells and the active growth of the main structural elements of the organ.

Infiltration of Local Immune Cells in the Sow Reproductive Tracts after Intra-Uterine and Deep Intra-Uterine Insemination with a Reduced Number of Spermatozoa is Less than Conventional Artificial Insemination

The present study investigated the infiltration of leukocyte subpopulations in the utero-tubal junction (UTJ) and each part of the oviducts at about 24 hr after intra-uterine insemination (IUI) and deep intra-uterine insemination (DIUI) compared to conventional artificial insemination (CAI) in sows. Fifteen crossbred Landrace x Yorkshire multiparous sows were used (CAI, n=5; IUI, n=5; DIUI, n=5). The sperm dose contained 3,000 × 10(6) (100 ml), 1,000 × 10(6) (50 ml) and 150 × 10(6) (5 ml) motile spermatozoa for CAI, IUI and DIUI, respectively. The sows were inseminated with extended fresh semen at 6 to 8 hr prior to the expected time of ovulation. At 25.2 ± 1.6 hr after insemination, the oviducts and the UTJ were collected. The tissue samples of UTJ, caudal isthmus, cranial isthmus and ampulla were transversely cut to a thickness of 5 µm and stained with H&E. The total numbers of lymphocytes, neutrophils, macrophages, eosinophils and plasma cells were determined under light microscope. It was found that the numbers of lymphocytes, eosinophils and macrophages after CAI, IUI and DIUI were not significantly different (P>0.1) in both epithelial and sub-epithelial connective tissue layer of the UTJ, caudal isthmus, cranial isthmus and ampulla. Intra-epithelial neutrophils in the UTJ were higher than cranial isthmus (P<0.05) and ampulla (P<0.05). In the UTJ, the intra-epithelial neutrophil in the CAI group was higher than DIUI group (P<0.01). Plasma cells in sub-epithelial layer of the endosalpinx in the CAI group were higher than DIUI group (P<0.05) and tended to be higher than the IUI group (P=0.08). In conclusion, compared to CAI, IUI and DIUI do not influence the infiltration of lymphocytes, macrophages and eosinophils in the UTJ and the oviduct prior to fertilization. But a lower number of neutrophils in the intra-epithelial layer of the UTJ and plasma cells in the sub-epithelial layers of the oviduct was observed in the DIUI group compared to CAI.

Prevalence of porcine reproductive and respiratory syndrome virus (PRRSV) antigen-positive uterine tissues in gilts culled due to reproductive disturbance in Thailand

The objective of the present study was to determine the prevalence of porcine reproductive and respiratory syndrome virus (PRRSV) antigen-positive uterine tissue in gilts culled due to reproductive disturbance in relation to age at culling, reasons for culling, herds, and PRRSV vaccination. Uterine tissues of 100 gilts from six swine herds in Thailand were collected. The immunohistochemistry was performed to detect the PRRSV antigen using a polymer-based non-avidin-biotin technique. PRRSV was detected in the cytoplasm of the macrophages in the subepithelial connective tissue layers of the endometrium in 33.0% of the culled gilts. The detection of PRRSV antigen varied among the herds from 14.3% to 80.0% (P = 0.018). The detection of PRRSV in the uterine tissues at different ages was not statistically different (29.6%, 39.4%, and 40.9% in gilts culled at 6-8, 9-10, and 11-16 months of age, respectively, P = 0.698), similar to the reasons for culling (P = 0.929). PRRSV antigen was found in 24.5% of the gilts vaccinated against the EU-strain-modified-live PRRSV vaccine and in 23.1% of the gilts vaccinated against the US-strain-modified-live PRRSV (P = 0.941). The level of antibody titers against PRRSV had no impact on PRRSV antigen detection in the uterine tissues. Similarly, the detection of PRRSV antigen did not differ between the virgin gilts (35.4%) and the gilts mated before culling (30.8%) (P = 0.622). It can be concluded that PRRSV remains in the uterine tissue of the infected gilts for several months even though vaccinations and acclimatization have been carried out.

Association between serum cortisol and progesterone concentrations and the infiltration of immune cells in the endometrium of gilts with vaginal discharge

The objective of the study was to investigate an association between serum cortisol and progesterone (P4) concentrations and the distribution of immune cells in the endometrium of the gilts with vaginal discharge. Genital organs from 39 Landrace×Yorkshire crossbred gilts culled owing to vaginal discharge problem were collected from two commercial swine herds in Thailand. The estrous stage and gross pathology were examined. Blood samples were collected from the jugular vein prior to being slaughtered. Serum P4 and cortisol were analyzed by means of enzyme immunoassay. The samples observed were in inactive (n = 4), follicular (n = 10), and luteal (n = 25) phases. They, afterwards, were processed in hematoxylin and eosin sections. The endometrium of the gilts was histologically divided into three layers, i.e., epithelial, subepithelial connective tissue, and glandular connective tissue layers. Immune cells, i.e., lymphocytes, neutrophils, eosinophils, macrophages, and plasma cells, in each layer were quantified under a light microscope (×400). The results revealed that mean serum cortisol was 430.6 ± 68.3 nmol/l. Serum P4 varied by ovarian status. Serum P4 of the gilts in the luteal phase was higher than those in the follicular phase (88.3 ± 7.7 versus 20.6 ± 6.2 nmol/l, P < 0.05). As for the endometrium condition, the gilts were classified into acute/subacute endometritis (n = 13), chronic endometritis (n = 9), and normal endometrium (n = 17). Neutrophils were the main local immune cells in the epithelial layer. Lymphocytes were the dominant population in the subepithelial and glandular connective tissue layers. Generally, the serum cortisol tended to negatively correlate with lymphocytes in the subepithelial connective tissue layer (r = −0.28, P = 0.081). In the gilts with acute/subacute endometritis, no correlation among serum cortisol, P4, and immune cells was observed. In chronic endometritis gilts, only a negative correlation was remarked between P4 and epithelial lymphocytes (r = −0.83, P = 0.010), epithelial neutrophils (r = −0.79, P = 0.019), and subepithelial neutrophils (r = −0.73, P = 0.025). In the gilts with normal endometrium, P4 negatively correlated with subepithelial neutrophils (r = −0.55, P = 0.022) while positively correlated with subepithelial macrophages (r = 0.54, P = 0.024) and subepithelial eosinophils (r = 0.60, P = 0.011).

Spermatophagy in the seminiferous tubules and excurrent ducts of the testis in Rhesus monkey and in man.

The fine structure of cells capable of phagocytosing spermatozoa in the testes and epididymes of monkeys and men was studied by means of transmission and scanning electron microscopy. Both resident cells, such as Sertoli cells and epithelia of the rete testis, and free cells, such as macrophages (spermatophages) were found to phagocytose spermatozoa or fragments of spermatozoa in the seminiferous tubules and excurrent ducts. The spermatophages develop from precursor cells which invade the seminiferous tubules. After phagocytosis of spermatozoa they increase in size and sometimes possess more than one nucleus. Large spherically shaped spermatophages are found in the epididymis. In the rete spaces of Macaca fascicularis spermatophages are able to penetrate the rete epithelia and reside in the subepithelial connective tissue layers. Spermatophagy is frequently seen in the gonads of older men and in certain cases of oligozoospermia. In Macaca an increased number of spermatophages occurs at the end of the spermatogenetic season.

The Sow Endosalpinx at Different Stages of the Oestrous Cycle and at Anoestrus: Studies on Morphological Changes and Infiltration by Cells of the Immune System

The aim of this study was to investigate the morphological changes of the sow endosalpinx and the distribution of leukocytes throughout the oestrous cycle and at anoestrus. Nineteen crossbred sows (Swedish Landrace x Swedish Yorkshire) at late dioestrus (three), prooestrus (three), oestrus (three), early dioestrus (three), dioestrus (three) and anoestrus (four) were used. Oviductal samples from three different parts (isthmus, ampulla and infundibulum), taken immediately after slaughter, were fixed, embedded in plastic resin and stained with toluidine blue or stored in a freezer at -70 degrees C until analysed by immunohistochemistry (prooestrus and anoestrus) with an avidin-biotin peroxidase method. Quantitative and qualitative examinations of oviductal epithelium and subepithelial connective tissue were performed by light microscopy. During all stages, a lower degree of morphological changes (pseudostratification, mitosis and secretory granules) was found in the isthmus compared with ampulla and infundibulum. In ampulla and infundibulum, pseudostratification, mitotic activity and secretory granules of the epithelium were high at prooestrus/oestrus. Cytoplasmic protrusions of epithelial cells with some extruded nuclei were prominent in ampulla and infundibulum at all stages except for oestrus and early dioestrus. Lymphocytes as well as CD2- and CD3-positive cells were the predominant immune cells in the epithelial layer. The numbers of lymphocytes and CD3-positive cells did not differ among segments and stages. Numbers of CD2-positive cells did not differ between prooestrus and anoestrus while the numbers were significantly higher in the infundibulum than in ampulla and isthmus. Neutrophils were only occasionally found and mainly in the infundibulum. In the subepithelial connective tissue layer, the two most commonly observed immune cell types were lymphocytes and plasma cells. The numbers of lymphocytes as well as CD2- and CD3-positive cells was lower in isthmus than in the other segments (p < or = 0.001). Higher numbers of plasma cells (p < or = 0.001) were found in infundibulum than in ampulla and isthmus. The numbers of lymphocytes and plasma cells were not significantly different between stages of the oestrous cycle. However, the number of neutrophils differed and were highest at prooestrus in ampulla and infundibulum. The numbers of CD2-, CD3- and CD79-positive cells did not differ between prooestrus and anoestrus whereas for CD14- and SWC3-positive cells, the numbers were higher at prooestrus (p < or = 0.05) than at anoestrus. In the oviduct, the morphology differed in ampulla and infundibulum with oestrous cycle stages, which indicates an effect by ovarian steroid hormones. The immune cell infiltration was less influenced by cyclic changes. However, the immune cell infiltration (in the connective tissue) in the upper part, especially infundibulum, differed significantly from the one in the lower part, isthmus, indicating different immune functions within various parts of the oviduct.

Influence of pre-ovulatory insemination and early pregnancy on the infiltration by cells of the immune system in the sow endometrium

The aim of this study was to investigate the distribution of leukocytes in the sow endometrium following insemination and during early pregnancy. Cross-bred multiparous sows (Swedish Landrace×Swedish Yorkshire) were artificially inseminated (AI) once at 20–15 h before ovulation. Blood samples were collected from the jugular vein 1 h before slaughter for analyses of oestradiol-17β and progesterone levels. The sows were slaughtered at 5–6 h (group I, n=4) after AI or at different times after ovulation: 20–25 h (group II, n=4), 70 h (group III, n=4), day 11 (group IV, n=3; first day of standing oestrus=day 1) and day 19 (group V, n=3). Uterine horns were flushed to control for the presence of spermatozoa and neutrophils (groups I–IV) and/or for recovery of oocytes and/or embryos (groups II–IV, control of pregnancy). Mesometrial uterine samples were fixed, embedded in plastic resin and stained with toluidine blue. The surface and glandular epithelia as well as subepithelial and glandular connective tissue layers were examined by light microscopy. A marked number of neutrophils and spermatozoa were observed in the flushings from the uterine horns of sows slaughtered at 5–6 h after insemination. All animals slaughtered after ovulation were pregnant but no morphological effect of pregnancy was observed until day 11. In the surface epithelium, the largest numbers of intraepithelial lymphocytes were found in groups II and III, the smallest number was found in group V. The largest number of lymphocytes within the glandular epithelium was found in group III. The largest number of macrophages within the surface and glandular epithelia were found in group I. Neutrophils were found within the surface epithelium only in groups I and II. In the subepithelial connective tissue layer, a high infiltration of neutrophils was found in groups I and II while the largest number of eosinophils was found in group IV. The largest number of lymphocytes was observed in group V. In conclusion, this study showed a variation in the infiltration and distribution of neutrophils, lymphocytes, macrophages, eosinophils and plasma cells in the endometrium following insemination and during different stages of early pregnancy. Particularly, the pattern of lymphocyte presence on day 19 of pregnancy, indicate that the lymphocyte function may play a role during embryonic attachment in the pig.

The sow endometrium at different stages of the oestrous cycle: studies on the distribution of CD2, CD4, CD8 and MHC class II expressing cells

The aim of this study was to investigate the distribution of CD2 +, CD4 +, CD8 + lymphocyte subpopulations and MHC class II expressing cells in the sow endometrium throughout the oestrous cycle. Fifteen crossbred multiparous sows (Swedish Landrace×Swedish Yorkshire), with an average parity number of 3.4±0.7 (mean±S.D.) were used. Uterine samples from the mesometrial side of both horns, taken immediately after slaughter at late dioestrus (day 17, n=3), prooestrus (day 19, n=3), oestrus (day 1, n=3), early dioestrus (day 4, n=3) and dioestrus (days 11–12, n=3), were stored in a freezer at −70°C until analysed by immunohistochemistry with an avidin–biotin peroxidase method using monoclonal antibodies to lymphocyte subpopulations and MHC class II molecules. The surface and glandular epithelium as well as connective tissue layers in subepithelial and glandular areas were examined by light microscopy. For the T lymphocyte subpopulations, all oestrous cycle stages and different tissue layers taken together, the most commonly observed cell type was CD2 + cells. The largest number of CD2 + cells within the surface and glandular epithelium were observed at oestrus and early dioestrus. In the surface epithelium, a larger number of CD8 + cells compared with CD4 + cells were observed and no CD4 + cells were found within the glandular epithelium at any stage of the oestrous cycle. In the subepithelial and glandular connective tissue layers, during the oestrus cycle stages, a larger number of CD4 + cells compared with CD8 + cells were found. Endothelial cells in the connective tissue generally expressed MHC class II. However, no obvious differences between oestrous cycle stages were observed. For other cells than endothelial cells, the result was as follows. In the surface epithelium, a large number of MHC class II expressing cells was observed at oestrus compared with the other stages. No MHC class II expressing cells were found at late dioestrus and dioestrus. MHC class II expressing cells were also found in the glandular epithelium, and in the subepithelial and glandular connective tissue layers during all oestrous cycle stages but with no significant differences between stages. In conclusion, the present study showed a variation in the distribution of T lymphocyte subpopulations (CD2 +, CD4 + and CD8 +) and MHC class II expressing cells in the sow endometrium during different stages of the oestrous cycle. Also a variation between different tissue layers was found. It is suggested that helper and cytotoxic function of the immune system have primary locations in different tissue layers of the endometrium.

The sow endometrium at different stages of the oestrous cycle: studies on morphological changes and infiltration by cells of the immune system

The aim of this study was to investigate the distribution of leukocytes and the morphological changes of the sow endometrium throughout the oestrous cycle. Fifteen crossbred multiparous sows (Swedish Landrace×Swedish Yorkshire), with an average parity number of 3.4±0.7 (mean±S.D.) were used. Blood samples were collected from the jugular vein 1 h before slaughter for analyses of oestradiol-17β and progesterone levels. Uterine samples from the mesometrial side of both horns, taken immediately after slaughter at late dioestrus, prooestrus, oestrus, early dioestrus and dioestrus, were fixed, embedded in plastic resin and stained with toluidine blue. The surface and glandular epithelium as well as subepithelial and glandular connective tissue layers were examined by light microscopy. The significantly highest surface and the glandular epithelium were observed at oestrus and dioestrus, respectively. The largest number of capillaries (underneath the surface epithelium) was found at oestrus. In the surface epithelium, the largest number of intraepithelial lymphocytes (IELs, round nucleus) was found at early dioestrus. The largest number of lymphocytes and macrophages within the glandular epithelium were found at early dioestrus and oestrus, respectively. In the subepithelial connective tissue layer, the most common type of leukocytes during all stages was the lymphocyte. The largest numbers of lymphocytes and neutrophils were found at oestrus while the largest number of eosinophils was found at dioestrus. The dominating cells of the immune system in the connective tissue of the glandular layer were lymphocytes and macrophages. The significantly largest numbers of lymphocytes and plasma cells were found at early dioestrus and dioestrus, respectively. The number of lymphocytes in the connective tissue of the glandular layer and the number of plasma cells in the subepithelial layer were positively correlated with the plasma level of progesterone ( P≤0.05). The numbers of capillaries and neutrophils in the subepithelial layer underneath the surface epithelium as well as the number of macrophages in both surface and glandular epithelium were positively correlated with the plasma level of oestradiol-17β ( P≤0.05). In conclusion, the present study showed a variation in the infiltration and distribution of lymphocytes, neutrophils, eosinophils, macrophages, mast cells and plasma cells in the sow endometrium during different stages of the oestrous cycle. Also morphological parameters (e.g. height of surface and glandular epithelium, capillaries density and degree of oedema) varied throughout the oestrous cycle.

Ultrasonography of the ureter during laparoscopic gynecological surgery.

The purpose of this study was to evaluate the ultrasonographic appearance and normal function of the ureter during gynecological surgery. The study group consisted of 14 gynecological patients scheduled for laparoscopy and 12 patients scheduled for laparotomy. Under standardized anesthesia conditions before pelvic surgery, the appearance, location, dimensions and peristaltic activity of the ureter were examined using a 7.5-MHz flexible laparoscopic linear transducer probe. Imaging of the ureter was possible in all cases. The ureteral lumen, mucosa, subepithelial connective tissue and muscular layer could be imaged as a tubular structure with low-level echoes. The separate layers, however, could not be differentiated by ultrasonography. The ureteral diameters at resting phase did not differ between the open surgery and laparoscopy groups. During peristaltic activity the maximal diameter was smaller in the laparoscopy group. The mean number of peristaltic waves was 23 +/- 7 waves per 5 min and this did not differ significantly between the open and laparoscopic surgery groups. Intermittent periods of retrograde flow were detected in 21 of the 26 patients. As seen in this study, ureteral location and function can be ultrasonographically evaluated during surgery and laparoscopic conditions do not have much influence on the ureter. The role of laparoscopic ultrasonography in lowering the incidence of ureteral complications in gynecological surgery needs further study.

The vasculature in chronic adult periodontitis: a qualitative and quantitative study.

Blood vessel features in periodontal pocket soft tissues may be significant in the pathogenesis and progression of chronic periodontitis. The aim of this study was to make a quantitative histological assessment of the vasculature in soft tissue biopsies from patients with chronic adult periodontitis and patients with healthy periodontal tissues. We have also investigated changes in tissue morphology at both the histological and ultrastructural level. Twelve interdental biopsies were obtained, 6 from chronic adult periodontitis patients and 6 from healthy volunteers. The specimens were sliced, fixed in 3% glutaraldehyde, postfixed in 1% buffered osmium tetroxide, dehydrated, and embeded in araldite. One micron semithin sections were differentially stained with a dichromatic technique. The number of blood vessels (BV) for sub-epithelial, superficial and deep connective tissue layers were then assessed. Only in the sub-epithelial connective tissue layer was there a significant increase in the number of blood vessels (95% Confidence interval [CI]) in the chronic adult periodontitis specimens when compared to healthy specimens. The results of this study seem to indicate that a dichromatic staining technique facilitates the identification and quantification of blood vessels in epoxy resin embedded specimens at light microscope level, and that there is an increase in the number of blood vessels in the chronic adult periodontitis lesions.

Histopathologic Changes of the Tympanic Membrane in Acute and Secretory Otitis Media

The histopathologic changes observed in 40 normal and inflamed temporal bones of infants and children are reported. The tympanic membranes of patients with acute and secretory otitis media underwent considerable swelling compared to those of normal controls. Tympanic membranes with acute otitis media were thicker than those with secretory otitis media, but the difference was not statistically significant. The epithelial layer showed an increase in the number of cell layers. The lamina propria demonstrated the most significant changes of all layers with a marked swelling due to edema, engorged blood vessels, and inflammatory cell infiltration. Increased numbers of distended capillaries were present, predominantly in the subepithelial connective tissue layer, while infiltration of inflammatory cells was mainly in the submucosal connective tissue layer. By contrast, the involvement of the mucosal layer was modest and was composed of cuboidal cells, except for small islands of metaplastic mucosa with mucus production occasionally encountered in specimens with secretory otitis media.

Acidic and basic FGF mRNA expression in the middle ear mucosa during experimental acute and chronic otitis media.

Fibroblast growth factors (FGFs) induce the proliferation and differentiation of cells of mesodermal and neuroectodermal origin. Using in situ hybridization, messenger ribonucleic acid encoding acidic FGF, basic FGF and FGF receptor 1 (FGFR1) were localized in the middle ear mucosa of experimental animals with acute and chronic immune-mediated otitis media with effusion (OME). Basic FGF-labeled cells were seen in the subepithelial connective tissue layer (SE) preferentially near the epithelial basement membrane. Acidic FGF-labeled cells were seen in the SE, preferentially near blood vessels and occasionally in the cellular middle ear effusion (CE). FGFR1-labeled cells were seen in the SE and in the CE. The distribution of labeled cells in the middle ear suggests that basic FGF is produced by fibroblasts, acidic FGF is produced by leukocytes, and FGFR1 is produced by both fibroblasts and leukocytes. A role is proposed for these peptides in the proliferation and maintenance of the middle ear submucosa during otitis media.

Three-dimensional architecture of the subepithelial connective tissue layer in the mouse retromolar region.

The three-dimensional architecture of the subepithelial connective tissue layer in the mouse retromolar region was studied by scanning electron microscopy after removal of the epithelial layer. The connective tissue papillae (CTP) of the taste bud papillae (the retromolar papillae) appeared as a barnacle-like in form and had the round depression, corresponding to the site of taste bud, on their top. The CTP of the retromolar papillae and the openings of the salivary glands were concentrated collectively in the narrow zone just posterior to the molar teeth. This topographical relationship seems to reflect a physiological function; i.e., the food ground by the molar teeth is dissolved in saliva and stimulates the taste buds in the retromolar papillae. Further, the conical or cylindrical CTP were arranged around the CTP of the retromolar papillae. It is suggested that the conical or cylindrical CTP play an important role in increasing the epithelial-connective tissue interface and in resisting the excessive force during mastication.

Improved Healing of Tympanic Membrane Perforations with Basic Fibroblast Growth Factor

We have investigated the effects of basic fibroblast growth factor (FGF) on the healing of tympanic membrane (TM) perforations. In the first series of experiments, a simple, round 1-mm perforation was made in the membrane and the effects of basic FGF examined. In a second series of experiments, basic FGF was tested on 2-mm perforations in which the borders were folded inward in order to delay normal healing. Topical applications of saline or basic FGF were administered onto gelfoam overlays of the TM perforations in 51 guinea pigs by delivering 5 microliters aliquots of PBS or 5 microliters of PBS containing 1 microgram of basic FGF on the day of surgery and daily thereafter. Repair of the lesions was evaluated 3, 5 or 8 days after surgery. The results show that basic FGF mediates faster healing of TM perforations by inducing rapid proliferation of the subepithelial connective tissue layer.

Description and clinical importance of the lymphatics of the vocal fold

Findings of the presence of lymphatics in the subepithelial connective tissue layer of the true vocal cord range from the statement that lymphatics are absent to the observation that a dense lymphatic network exists. This is undoubtedly a result of the different methods of examination. The entire extent of a lymphatic system can be shown by either an enzyme histochemical demonstration of the 5'-nucleotidase activity in the lymphatics, or electron microscopy, which is more elaborate. These two methods are used to describe a subepithelial lymphatic network of varying density in 80 human vocal folds, which--contrary a frequent assumption--is not interrupted in the area of the free margin of the true vocal cord. Under the squamous epithelium, the density of the lymphatic system, which is very high in the arytenoid region, decreases continuously toward the anterior portion of the true vocal cord. It is exactly in the region in which the lymphatic system is the sparsest that almost all cancers of the true vocal cord develop. This finding is highly significant, in view of the low incidence of lymphogenous metastasis formation in T1-glottic cancers.

Cholesteatoma--pathology and treatment.

(1) The prerequisite for development of cholesteatoma is a cholesteatoma bed, that is a loose subepithelial connective tissue layer which acts as a nutrient bed and makes papillary growth of squamous epithelium possible. (2) The formation of cholesteatoma is facilitated by disturbed tubal function with reduced ventilation of the middle ear. (3) The progression of cholesteatoma, especially the bone destruction, is due to enzyme-activated cell groups. The epidermal layer in the postero-superior area of the tympanic membrane has a higher papillary content and during an inflammatory process there is a marked vascular reaction. This particular area has a special nutritional zone and the epidermis is especially well nourished [Lange, 1925]. The main artery to the tympanic membrane travels along the handle of the malleus and gives off branches. In our animal experiments epithelial cones grew into this well-nourished subepithelial zone and formed cholesteatoma. The importance of tubal function as regards cholesteatoma formation can be seen in everyday clinical practice. In stapedectomy patients, the lateral attic wall is usually removed to allow full visualisation of the stapes, but retraction pockets in this area are never seen at subsequent follow-up. However, if the lateral attic wall is removed during surgery for chronic otitis media, reconstruction with cartilage or ceramic is necessary to prevent retraction. This adds weight to the hypothesis that tubal dysfunction is an important aetiological factor in cholesteatoma. This is further supported by the 30 times greater incidence of retraction pockets in patients with cleft palate.