Long-term survival after surgery for stage III-IV maxillary sinus carcinoma.

OBJECTIVES: How to optimally treat maxillary sinus carcinoma is subject to debate. This study assessed how clinical features and treatment modalities corresponded with long-term survival. METHODS: Sixty-five patients at our institution were diagnosed with maxillary sinus carcinoma from 1982 to 2003. The median follow-up time was 92.9 months. We evaluated the prognostic value of age, gender, symptoms at presentation, histological classification, tumour stage, and treatment modality with regard to overall survival. RESULTS: The five-year survival rate was 52%. Age (p = 0.03), TNM stage (p = 0.04), T classification (p = 0.04), nodal involvement (p = 0.03), and surgery (p = 0.04) were significant prognostic factors for overall survival. There was a significant difference in the overall survival rate and months of survival between patients who underwent surgery and those who had nonsurgical treatment (p = 0.04). In patients with T3 disease, patients who received en bloc surgery had a higher overall survival than patients who received piecemeal surgery (p = 0.045). Multivariate analysis revealed that T classification was the most powerful prognostic factor for overall survival (p = 0.026), followed by nodal involvement (p = 0.036). Surgery was a marginally significant prognostic factor (p = 0.066). CONCLUSIONS: Although multivariate analysis showed that T classification and nodal involvement corresponded more with survival than did surgery, we conclude that adequate surgical removal should be an integral component of multimodal treatment.

Lipid fluidity and composition of intestinal microvillus membranes isolated from rats of different ages.

The lipid composition and fluidity of microvillus (luminal) membranes isolated from the small intestines of Fisher 344 rats aged 6, 17, and 117 weeks were compared. Lipid fluidity, as assessed by the fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene, was significantly greater in rats aged 6 weeks as compared to 17 or 117 weeks. A lipid thermotropic transition was observed at 17.5 +/- 1.3 degrees C in the membranes of the youngest group, approx. 5-6 degrees C lower than that of the older animals. The differences in lipid composition which account for the higher fluidity of the youngest preparations include a decreased cholesterol/phospholipid molar ratio in both the proximal and distal halves of the small intestine and, in the proximal half alone, increases in the lipid/protein ratio and double bond index. The foregoing reduction in cholesterol/phospholipid ratio derives mainly from a higher content of total phospholipid, and the increment in double bond index results from an increase in arachidonic acid residues. The results demonstrate an age-dependent decrease in fluidity of intestinal microvillus membranes in the early post-weaning period in the rat. This pattern was unlike that of the microvillus membrane p-nitrophenylphosphatase, whose specific activity declined progressively in the older age groups.

Development of intestinal brush border membrane proteins in the rat.

1. The proteins of the intestinal microvillus membrane have been studied during post-natal development in the rat (days 12--37). 2. In suckling animals (up to age 20 days), the majority of alkaline phosphatase, glucoamylase and lactase activities in the distal half of the intestine were located in the supernatant fraction (100000 X g, 60 min). These enzymes were attached to the membrane from the proximal intestine at all ages. 3. Alkaline phosphatase, maltase and lactase activities in the supernatant fractions chromatographed in Sephadex G-200 in positions similar to the corresponding membrane enzyme. Corresponding activities for lysosomal counter-parts of maltase and lactase present in the supernatant fraction chromatographed differently. Moreover, pH optimum of the soluble enzymes was 9.2 for phosphatase and 5.5--6.0 for glycoamylase and lactase. The soluble lactase and alkaline phosphatase were inhibited minimally by p-chloromercuribenzoate, and sodium fluoride respectively. L-Phenylalanine (20 mM) did inhibit the soluble phosphatase by 90%. Thus, the soluble enzymes are not mainly of the lysosomal origin, but have characteristics of membrane-bound enzymes. 4. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate revealed 18 protein bands which were present in adult membranes. Two other proteins were unique for membranes of distal intestine in suckling rats. The proteins corresponding to known enzyme activity changed as expected with age (e.g. sucrase, maltase increased, lactase decreased). Most of the other proteins were also altered in amount during development. Thus, the changes in the microvillus membrane during development in the rat are not limited to specific enzymes.

Signal transduction pathways of nitric oxide release in primary microglial culture challenged with gram-positive bacterial constituent, lipoteichoic acid.

Between one-third and one-half of all cases of sepsis are known to be caused by gram-positive microorganisms through the cell wall component, e.g. lipoteichoic acid (LTA). Gram-positive bacteria are also known to induce encephalomyelitis and meningeal inflammation, and enhance the production of nitric oxide (NO) via expression of inducible nitric oxide synthase (iNOS) in murine tissue macrophages. It remains to be explored if LTA could activate microglia considered to be resident brain macrophages. We report here that LTA derived from gram-positive bacteria (Staphylococcus aureus) significantly induces NO release and iNOS expression in primary microglia. LTA-induced NO accumulation was detected at 2 h in microglial culture and was significantly attenuated by pretreatment with anti-CD14, complement receptor type 3 (CR3) or scavenger receptor (SR) antibodies. LTA activated mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase, p38 MAPK or c-Jun N-terminal kinase in cultured microglia. LTA-elicited microglial NO production was also drastically suppressed by SB203580 (p38 MAPK inhibitor) or pyrrolidine dithiocarbamate (an inhibitor of nuclear factor kappaB), indicating that p38 MAPK and nuclear factor kappaB were involved in microglial NO release after LTA challenge. These results suggest that gram-positive bacterial product such as LTA can activate microglia to release NO via the signal transduction pathway involving multiple LTA receptors (e.g. CD14, CR3 or SR), p38 MAPK and nuclear factor kappaB. The in vivo study further confirmed that administered intracerebrally LTA induced considerable noticeable iNOS, phospho-IkappaB and phospho-p38 MAPK expression in microglia/macrophages.

Treatment-associated severe thrombocytopenia affects survival rate in esophageal cancer patients undergoing concurrent chemoradiotherapy.

BACKGROUND: Esophageal cancer is commonly treated with surgery, concurrent chemoradiotherapy (CCRT), or a combination of both. The correlation between the hematological parameters during CCRT and early survival of esophageal cancer has not been fully evaluated. MATERIALS AND METHODS: We analyzed the records of 65 esophageal cancer patients treated by CCRT between 2007 and 2010 retrospectively. The association between CCRT-associated myelosuppression, demographic variables, and survival rates were analyzed by univariate and multivariate analysis. RESULTS: The univariate analysis showed that tumor extent of T3-4, a higher stage of tumor, a lower albumin level, grade 3 or higher anemia and thrombocytopenia, and interruptions in treatment affected survival rates. Further, the multivariate analysis revealed that stage IV (P = 0.030) is an independently negative prognostic factor for a one-year survival rate. Stage IV (P = 0.035), tumor extent of T3-4 (P = 0.002), and grade 3-4 thrombocytopenia (P = 0.015) are independently negative prognostic factors for a two-year survival rate. CONCLUSIONS: Severe decrease in platelet count during CCRT independently affects survival of esophageal cancer patients in addition to stage of the tumor.

Expression of B7-1 by Pam 212 squamous cell carcinoma enhances tumor cell interactions with dendritic epidermal cells but does not affect in vivo tumor growth.

Direct antigen presentation of tumor-associated antigens by tumor cells to T lymphocytes may induce clonal anergy as a mechanism of escape from immune surveillance. B7-1 is a costimulatory molecule for the activation of both CD4+ and CD8+ T lymphocytes that prevents the induction of clonal anergy. Thus, the transfer of B7-1 genes into tumor cells can induce protective immunity and lead to tumor rejection of some tumors in model systems of in vivo tumor growth; however, there is no information on whether stable expression of B7-1 can affect the in vivo growth of squamous cell carcinoma, a common skin cancer. Here, we study how the stable cell surface expression of high levels of B7-1 by Pam 212, a murine squamous cell carcinoma, affects tumor cell-lymphocyte interactions (lymphocyte proliferation and cytotoxicity). Consistent with its costimulatory role, we demonstrate that B7-1 can efficiently induce dendritic epidermal T-cell proliferation in three different dendritic epidermal T-cell cell lines. In addition, B7-1 enhances dendritic epidermal T-cell cytolytic activity against Pam 212 cells in an in vitro 51Cr-release assay, which was blocked by CTLA-4/Ig fusion protein. In contrast to dendritic epidermal T cells, the expression of B7-1 does not alter Pam 212 interactions with either cytotoxic T-lymphocytes, natural killer, or lymphokine-activated killer cells. B7-1 expression by Pam 212 cells did not alter its ability to grow tumors in vivo, as their rate of tumor growth was the same as vector-transfected Pam 212 cells, which were B7-1 negative. Our studies indicate that B7-1 gene transfer into Pam 212 does not alter its tumorigenicity, because it does not alter tumor cell-lymphocyte interactions with cytotoxic T lymphocytes, natural killer cells, and lymphokine-activated killer cells. Further studies of B7-1 modified Pam 212 and dendritic epidermal T cells will clarify whether T-cell receptor-gamma/delta-bearing T lymphocytes can play a role in immunotherapy of Pam 212 squamous cell carcinoma.

Corticosterone concentrations in the serum and milk of lactating rats: parallel changes after induced stress.

Transfer of corticosterone from serum to milk was studied in lactating rats after ether and pentobarbital anesthesia. Two minutes after the onset of anesthesia stress, total serum and milk corticosterone concentrations were not significantly different. By 30 min, corticosterone concentrations in serum increased to a peak and plateaued at about this level during the 2-h experimental period, while concentrations in milk reached a maximal plateau only at 50 min poststress. The peak corticosterone concentrations in serum and milk were 76 +/- 6 and 36 +/- 4 micrograms/dl, respectively. By centrifugal ultrafiltration dialysis, the percentages of free corticosterone in serum and milk were not significantly different at the maximal concentrations; thus, free corticosterone in serum was about 200% of that in milk. In contrast, anesthesia stress had no effect on serum and milk corticosteroid-binding globulin concentrations; the serum to milk ratio was approximately 10:1. No accumulation of corticosterone in milk was observed after repeated ether stress. Decreases in milk corticosterone levels after recovery from ether stress paralleled that of its serum counterpart. These results indicate that corticosterone concentrations in milk increase rapidly after ether stress, but are limited to a level significantly lower than that in serum. The possible effects of corticosterone in milk on the development of infant rats remains to be defined.

Induction of intestinal differentiation by systemic and not by luminal corticosterone in adrenalectomized rat pups.

Potential effects of corticosterone (cort) from maternal milk on intestinal differentiation were studied using adrenalectomized (adx) rat pups fed a formula containing differing amounts of cort. Formula cort concentrations in the range found in milk (0.1-0.5 micrograms/ml) increased the survival of adx rats, but did not induce intestinal differentiation. Formulae containing 1.0-50.0 micrograms/ml cort caused a dose-dependent elevation of serum cort concentrations and jejunal maltase activity and precocious jejunal sucrase induction. Adx rats receiving the formula containing 10 micrograms/ml cort showed serum cort concentrations similar to those in day 15 control rats and jejunal sucrase and maltase activities equivalent to those in day 18-20 control rats, suggesting that the rise in serum cort that occurs during postnatal development suffices to modulate intestinal differentiation. To distinguish between direct local and systemic effects of luminal cort on intestinal differentiation, expression of sucrase was determined in jejunal isografts and in host jejunum from adx rats fed luminal cort. Jejunal isografts and host jejunum expressed similar sucrase activities and showed similar immunofluorescent staining. Moreover, administration of cort by continual ip infusion was more effective than continual intragastric infusion in inducing intestinal sucrase and maltase activities. These data imply that luminal cort is absorbed and transported into the systemic circulation before inducing intestinal epithelial cell differentiation through the systemic route.

Production of multiple cytokines and induction of cachexia in athymic nude mice by a new anaplastic thyroid carcinoma cell line.

An anaplastic thyroid cancer cell line, Thena, was recently established in our laboratory following radical thyroidectomy of a patient with anaplastic thyroid cancer. Microscopically, Thena cells were spindle-shaped or small round cells. Thena cells were reactive with cytokeratin AE1/AE3 antibodies, epithelial membrane antigen, interleukin (IL)-6, epithelial growth factor receptor, transforming growth factor (TGF)-alpha, vascular endothelial growth factor, and vimentin. Thena cells secreted high levels of IL-6, leukemia inhibitor factor (LIF), tumor necrosis factor (TNF)-alpha, and TGF-beta1 in the culture supernatants, as determined by enzyme-linked immunosorbent assay. When subcutaneously injected with Thena cells, athymic nude mice developed tumor masses in the skin within 2 weeks. Furthermore, Thena cells induced cachexia in these tumor-bearing mice. High levels of human IL-6, LIF and TGF-beta1 were detected in the mouse sera. To our knowledge, the Thena cell line is the first thyroid cancer cell line reported to induce cachexia in nude mice. This cachectic animal model is worthy of further study to explore the treatment of thyroid cancer-induced cachexia.

Ginkgo biloba extract enhances noncontact erection in rats: the role of dopamine in the paraventricular nucleus and the mesolimbic system.

Penile erection is essential for successful copulation in males. Dopaminergic projections from the paraventricular nucleus (PVN) to the ventral tegmental area (VTA) and from the VTA to the nucleus accumbens (NAc) are thought to exert a facilitatory effect on penile erection. Our previous study showed that treatment with an extract of Ginkgo biloba leaves (EGb 761) enhances noncontact erection (NCE) in male rats. However, the relationship between NCE and dopaminergic activity in the PVN, VTA, and NAc remains unknown. The present study examined the relationship between NCE and central dopaminergic activity following EGb 761 treatment. We report here that, in comparison with the controls, there was a significant increase in the number of NCEs in rats after treatment with 50 mg/kg of EGb 761 for 14 days. EGb 761-treated rats also showed more NCEs than the same group before EGb 761 treatment. A significant increase in the expression of catecholaminergic neurons in the PVN and the VTA was seen by means of tyrosine hydroxylase immunohistochemistry, and tissue levels of dopamine and 3,4-dihydroxyphenylacetic acid in the NAc were also markedly increased in the EGb 761-treated animals. However, the norepinephrine tissue levels in the PVN and the NAc in the EGb 761-treated group were not significantly different from those in the controls. Together, these results suggest that administration of EGb 761 increases dopaminergic activity in the PVN and the mesolimbic system to facilitate NCE in male rats.

Small intestine of artificially reared rat pups: weight gain and changes in alkaline phosphatase, lactase and sucrase activities during development.

Comparative studies on small intestinal development in artificially reared (AR) and in mother-fed (MF) rats were carried out. When pups at 12 days of age were reared by continuous intragastric infusing of a cow milk formula (CMF), they gained weight equal to MF rats until 20 days; their small intestine weight was approximately 40 and 23% greater than that of MF rats at 16 days and 22 days of age, respectively. Autoradiographic studies indicated that the intestinal DNA synthetic index was 74-85% higher in AR than in MF rats at 16 days; similarly intestinal crypt depth and duodenal villus length were significantly higher in AR rats. The developmental pattern of duodenal alkaline phosphatase activity was similar in both AR and MF rats. In contrast, AR rats showed precocious decrease of lactase activity in the ileum at 16 days and in the jejunum at 18 days; but total lactase activity in the intestine was not different from MF rats at 16 days. Jejunal sucrase activity in AR rats was precociously induced and elevated. It was concluded that the intestine of AR rats undergoes structural and enzymic modifications. The physiological significance of these changes remains to be elucidated.

Small intestine of artificially reared rat pups: effect of caloric intake and dietary composition on growth and disaccharidase activities.

When rats were fed a cow milk formula (CMF) from 12 to 16 days of age at a caloric intake sufficient to support a body weight gain equal to mother-fed (MF) rats, their small intestine outweighed that of MF rats by 40%. If the caloric intake was reduced by approximately 40%, artificially reared (AR) rats exhibited intestinal weights similar to MF rats, but their body weight was lower than MF rats. Sucrase specific activity was precociously increased in all AR rats; this increase was higher in rats with low caloric intake than rats with high caloric intake. Conversely, lactase specific activity was significantly decreased in the ileum of all AR rats. As compared to MF rats, the total lactase activity was significantly lower only in rats with low caloric intake. When AR rats were fed a modified Ross Carbohydrate-Free formula (RCF) containing the same caloric density of protein, fat, and carbohydrate as rat milk, the intestinal growth and disaccharidase activities were the same as those of AR rats fed CMF. It is concluded that the weight gain of small intestine depends on the caloric intake of AR rats and both CMF and RCF are nutritionally equal in supporting intestinal growth. Changes in sucrase and lactase activities in AR rats appear to have no relation to compositional differences in CMF and RCF.

Cell kinetics in the small intestine of suckling rats. I. Influence of hypophysectomy.

Cell kinetics have been examined in the duodena of intact rats at 6, 16, and 22 days of age, and of hypophysectomized rats at 22 days. In intact rats the crypt population per villus increases more than 10-fold, the greater part of the increase occurring late in the third week. The labelling index does not differ between 6 (28.3%) and 16 (27.6%) days, but increases to 37.8% at 22 days. Generation time also does not differ between 6 (18.0 hours) and 16 (17.7 hours) days, but falls to 10.8 hours at 22 days by shortening of both the presynthetic and synthetic phases. Acceleration of cell migration rate between 18 and 19 days of age results in shortening of cell transit time from seven days in rats younger than 18 days to two days in those older than 18 days. When rats are hypophysectomized at six days, the duodenal crypt population per villus at 22 days is comparable to that of intact rats at 16 days. The labelling index at 22 days is 19% below that of intact rats at six days. Generation time at 22 days is slightly shortened by a decrease of the presynthetic phase, but the duration of 15.5 hours is 43% longer than in intact rats at the same age. Despite the small crypt population and the low cell production rate, the cell-transient time in 22-day-old hypophysectomized animals is only three days.

Ontogenic timing mechanism initiates the expression of rat intestinal sucrase activity.

Morphologic and enzymic differentiation occurs in rat small intestinal epithelium during 16-20 days of postnatal life. This change is considered to be initiated by an ontogenic timing mechanism and is modulated by extrinsic systemic and luminal factors. The importance of the ontogenic timing was tested directly using a transplantation technique in which jejunal isografts from newborn (day 0) and 5-day-old (day 5) rats were implanted under the skin of newborn (day 0) hosts. Isografts showing cryptvillus architecture were obtained in 44% and 21% of transplants, respectively. Day 0 isografts and host intestine expressed sucrase activity at about 16-18 days of age and showed similar crypt cell labeling and epithelial migration after [3H]thymidine injection. Day 5 isografts expressed sucrase activity when the hosts were 13 days of age, whereas host intestine showed no detectable sucrase activity. Isograft lactase activities in both experimental transplant models were significantly higher than host intestinal lactase up to 28 days of age, suggesting that luminal factors are important in modulating lactase activity during the first 4 wk of postnatal life. It is concluded that (a) no systemic factors at day 13 inhibit the expression of sucrase activity and (b) an ontogenic timing mechanism in the jejunum initiates the expression of sucrase activity.

Use of pup in a cup model to study gastrointestinal development: interaction of nutrition and pituitary hormones.

The novel technique of artificial rearing (AR) of rat pups circumvents the difficulty of controlling diet composition and caloric intake. For studies of effects of nutrition and hormone interactions on gastrointestinal development, an appropriate experimental approach is to use AR rats whose corticosterone production is inhibited or abolished. Hypophysectomized (Hx) rats were used to examine whether growth retardation after Hx results from reduced caloric intake. Hx, sham-Hx and intact rats were isocalorically fed a cow-milk formula from day 12 to 18. Mother-fed (MF) Hx and intact rats were used as baseline controls. MF-Hx showed retarded intestinal growth, decreased body weight gain and reduced skeletal growth. In contrast, AR-Hx rats showed intestinal hypertrophy, normal body weight gain and reduced skeletal growth. Intestinal lactase activity remained higher in MF-Hx or AR-Hx rats than in control groups. AR-Hx rats showed no precocious increase of intestinal maltase and sucrase activity as did AR controls. Trace levels of serum growth hormone was detectable in MF-Hx but not in AR-Hx rats. We conclude that caloric intake can promote intestinal and somatic growth in the absence of the pituitary gland and pituitary hormones are required for skeletal growth and intestinal enzymic differentiation.

Effects of starvation and refeeding on jejunal disaccharidase activity.

In the rat, starvation lowers jejunal sucrase activity and increases or has no effect upon jejunal lactase activity. The mechanism by which starvation influences these intrinsic microvillus proteins remains unclear. Jejunal sucrase and lactase activities were studied during starvation or refeeding after a three-day fast. Using polyclonal monospecific antibodies, sucrase-isomaltase (SI) and lactase-phlorizin hydrolase (LPH) protein contents were measured in parallel to determine changes in enzyme activation. Sucrase activity and SI protein fell after two and three days of fasting and rose during refeeding. In contrast, lactase activity and jejunal LPH content increased after starvation and decreased after refeeding for 48 hr. For both enzymes, changes in catalytic activity and protein content occurred in parallel. [3H]Leucine incorporation studies in vivo showed more labeling of immunoprecipitable LPH than SI during starvation, but refeeding induced relatively more labeling of SI than of LPH. Therefore, starvation and refeeding produce opposing effects upon jejunal lactase and sucrase activities by modulating LPH and SI protein production and not by modifying enzyme activation.

Colonic proliferation is increased in senescent rats.

Our previous studies suggested that crypt size enlarged and that proliferation rate might be greater in the small intestine of rats during senescence. Crypt cell numbers and crypt cell proliferation rates, using the vincristine-induced metaphase arrest technique, now have been measured in the colon of aging and young Fischer 344 rats. The proximal colon of 26-28-mo-old unfasted rats had 10% more crypt cells and a higher proliferative rate than 3-4-mo-old young controls. In the distal colon, the crypt cell proliferation rate in aging rats was 56% greater than in the young. A 3-day fast reduced crypt cell proliferation about fourfold in young rats but only by 20% in aging rats. One-day refeeding abruptly increased the crypt cell population and proliferation rate in rats of both age groups. The crypt zone of proliferating cells from aging rats was broader than that seen in young rats. In addition, starvation lowered colonic crypt cell cycling rate much less in aging than in young animals. We conclude that the colons of aging rats demonstrate a hyperproliferative state and a failure to adapt appropriately to changes in food intake. These observations may be relevant to states of altered proliferation that occur in the premalignant colon.

Hormonal influences on the growth and enzymic differentiation of the small intestine of the hypophysectomized rat.

When rats are hypophysectomized in neonatal life, the growth of the small intestine is more severely retarded than the growth of the body as a whole. It was shown previously that intestinal growth is not rectified by doses of cortisone and/or throxine that restore normal activity of brush border enzymes in hypophysectomized sucklings; growth hormone did not affect relative weight or enzyme activity. Reexamination of this problem with much lower doses of hormones than previously employed has now shown that relative weight of the intestine is enhanced by cortisone and thyroxine together, and is normalized by cortisone and thyroxine in combination with rat growth hormone. Growth induced by treatment with the three hormones involved increases of crypt depth and villus height, and of mitotic index. Body weight was not affected by hormonal treatment, but the tails of the hypophysectomized sucklings were significantly lengthened by thyroxine alone, the effect being enhanced when growth hormone was also given. The physiological dose of hormones used in the present study were as effective in elevating activity of alkaline phosphatase and sucrase as the larger doses previously used. Cortisone had a greater effect on sucrase, thyroxine on phosphatase. Pentagastrin did not influence either growth or enzyme activity.

Biosynthesis and transport of glycoproteins in the small intestinal epithelium of rats. I. Developmental change and effect of hypophysectomy.

The biosynthesis and intracellular transport of glycoproteins in duodenal absorptive cells of intact rats at 6 and 24 days and hypophysectomized rats at 24 days of age were studied after 20 min intralumenal pulse-labeling of D-[3H]galactose, L-[3H]fucose, or D-[3H]mannose. Autoradiographic studies showed that the incorporation of sugars increased significantly in intact rats between 6 and 24 days. When rats were hypophysectomized at 6 days of age, the intestinal epithelium at 24 days incorporated D-[3H]galactose at a level significantly lower than that of intact rats at 24 days. Hypophysectomy also interfered with the developmental increase in D-[3H]mannose, but not in L-[3H]fucose, incorporation. Biochemical study indicated that the radioactivity in the lipid-free acid-precipitable glycoproteins in the intestine of 24-day-old intact rats at 20 min after D-[3H]galactose injection was 129% and 97% higher than that in 6-day-old rats and in 24-day-old hypophysectomized rats, respectively. The patterns of intracellular transport of newly synthesized galactosylated or fucosylated glycoproteins in all animal groups were similar; the labeled glycoproteins were initially present in the Golgi and were transported through the smooth endoplasmic reticulum to either the lateral membrane or the brush-border membrane within 60 min after the injection of labeled sugars. The proportion of labeled glycoproteins that migrated to the brush-border membrane, however, increased about twofold in the intact rats between 6 and 24 days of age at 60-240 min after D-[3H]galactose injection. Hypophysectomy interfered with developmental increase in the transport of glycoproteins from the apical cytoplasm to the brush-border membrane. It was concluded that the incorporation of monosaccharide precursors into glycoproteins and the proportion of newly synthesized galactosylated or fucosylated glycoproteins transported to the brush-border membrane increase during postnatal development. The developmental changes are regulated, at least partially, by the pituitary gland.

Epithelial cell cultures from the colon of the suckling rat.

Epithelial cells from the colon of suckling rats have been propagated in vitro. The colons were excised and cut longitudinally. The epithelial sheets were peeled off and dissociated in 0.1% trypsin solution at 25 degrees C for 10 min. The first cell suspension was discarded and the remaining fragments trypsinized again for an additional 20 min. The dissociated cells were washed and cultured. Forty-eight hours later, several epithelial colonies consisting of closely packed polygonal cells were formed. Transmission and scanning electron microscope examination of the colonies showed numerous regularly spaced microvilli on the surface and tight junctions and desmosomes between adjacent cells. Immunocytochemical studies with antiserum prepared against the brush-border membrane of the colonic epithelium showed specific staining of the epithelial colonies. Epithelial colonies were subcultured by the penicylinder method. Although the subcultured cells retained their epithelial characteristics, the proliferative activity of the cells gradually decreased. Currently, efforts are being made to determine the optimum nutritional requirements of the primary and low-passage cultures.