Involvement of 8-hydroxyguanine formation in the initiation of rat liver carcinogenesis by low dose levels of N-nitrosodiethylamine.

The question of whether 8-hydroxyguanine (8-OHG) formation is involved in initiation by low dose levels of N-nitrosodiethylamine (DEN) was addressed using a rat liver model. Male Fischer 344 rats, 6 weeks of age, were administered single i.p. doses of DEN between 0.001 and 100 mg/kg body weight. The 8-OHG levels in liver DNA were measured within 72 h thereafter in randomly selected rats. The remaining rats were given either no further treatment, partial hepatectomy (PH) at hour 4, or PH with i.p. administration of 500 mg/kg body weight of colchicine on days 1 and 3. A selection procedure was performed between weeks 2 and 4, and the initiating activity of DEN was assessed in terms of development of gamma-glutamyltransferase-positive foci at week 5. The 8-OHG levels in the liver DNA were significantly elevated between hours 6 and 72 in a manner dependent on the DEN dose. Dose-dependent induction of foci was similarly noted with doses of 1-100 and 0.001-100 mg/kg body weight in the non-PH and the PH rats, respectively. The sizes of the foci were also significantly increased in a manner dependent on the DEN doses of 1-100 and 0.001-100 mg/kg body weight in the non-colchicine-treated and the colchicine-treated rats, respectively. Statistically, linear trends of 8-OHG formation due to DEN were different at 0.001-0.1 and 1-100 mg/kg body weight, but the total adducts formed within 72 h of the administration proved to be closely related to the development of foci at the termination. These results indicate that 8-OHG formation in the liver DNA may be involved in DEN initiation of hepatocarcinogenesis even at low dose levels, and that single i.p. doses of 0.001-0.1 and 1-100 mg/kg body weight might exert different effects.

Peptide histidine methionine may be a prolactin-releasing hormone in humans.

Peptide histidine isoleucine (PHI) was initially isolated from the porcine gastrointestinal tract and may be present in the brain. It has been suggested that PHI may be PRL-releasing hormone (PRH) because of its potent PRL-releasing activity and its existence in hypophysial portal plasma in rats. Vasoactive intestinal peptide and PHI are coded by the same gene, and human PHI has a C-terminal methionine instead of isoleucine [peptide histidine methionine (PHM)]. To investigate the possibility that PHM is a physiological PRH in humans, we measured the immunoreactive PHM concentration in human hypothalamic tissue and cerebrospinal fluid (CSF) using a specific RIA. We also examined in vivo the PRH activity of synthetic PHM. The human hypothalamus contained 19.3 +/- 6.2 (+/- SD; n = 5) pmol/hypothalamus, very similar to the content of GHRH or CRH. Immunoreactive PHM was also present in CSF; its levels in CSF were significantly lower in patients with prolactinomas than in control subjects. The CSF PHM levels in such patients increased after correction of hyperprolactinemia by long term bromocriptine therapy. The CSF PHM levels also were low in pregnant women. There was a significant negative correlation between plasma PRL and CSF PHM levels in all of these subjects. Gel filtration profiles of CSF extracts from normal subjects revealed two peaks of immunoreactive PHM: a high mol wt peak and one at the elution position of synthetic PHM. This profile resembled that of hyppothalamic extract. In contrast, only high mol wt material was detected in CSF from hyperprolactinemic subjects. Intravenous administration of synthetic PHM elicited a significant increase in plasma PRL in normal subjects; the responses to PHM were higher in women than in men. The presence of large amounts of immunoreactive PHM in the human hypothalamus suggests that PHM may participate in the regulation of anterior pituitary hormone secretion. Its specific PRL-releasing activity in vivo and the low CSF PHM levels of hyperprolactinemic subjects suggest that PHM may be a physiological PRH in humans.

Urocortin expression in human pituitary gland and pituitary adenoma.

Urocortin is a recently identified neuropeptide of the CRF family in the mammalian brain, but its expression in human tissue has been little studied. In this study, we examined urocortin expression in human anterior pituitary gland and pituitary adenomas by RIA, high performance liquid chromatography, immunohistochemistry, messenger ribonucleic acid (mRNA) in situ hybridization, and reverse transcriptase-PCR. Immunoreactive urocortin concentrations in normal pituitary tissue extract were 103.25 +/- 39.05 ng/g wet wt (mean +/- SEM; n = 4), and their levels were all significantly higher than those in other portions of central nervous system of the same subjects. High performance liquid chromatography analysis of human pituitary extract demonstrated a single peak corresponding to that of the expected chromatographic mobility of synthetic human urocortin-(1-40). Urocortin-immunoreactive cells were detected in the anterior pituitary gland. Neither urocortin-immunoreactive nerve fibers nor cells were detected in the posterior lobe. Immunostaining in serial mirror tissue sections revealed that 76.55 +/- 3.06% of urocortin-immunoreactive cells expressed GH immunoreactivity, whereas 22.25 +/- 3.02% and less than 1% of urocortin-immunoreactive cells expressed PRL and ACTH, respectively. mRNA hybridization signals of urocortin were also detected in urocortin-immunopositive pituitary cells. The reverse transcriptase-PCR analysis demonstrated a 145-bp RNA band corresponding to that of the expected length of urocortin in all cases of normal pituitary glands examined (n = 3). We also immunostained urocortin in 52 cases of human anterior pituitary adenomas, including GH-producing adenomas (n = 14), ACTH-producing adenomas (n = 13), PRL-producing adenomas (n = 11), and nonfunctioning hormonally inactive adenomas (n = 14). No urocortin immunoreactivity was detected in these adenoma cells, except for one case of GH-producing adenoma and one case of nonfunctioning adenoma. We also performed mRNA in situ hybridization in 27 adenomas. No hybridization signals were detected in these adenomas, except in two cases. The results described above indicated that urocortin is synthesized in human anterior pituitary cells and may play an important role in biological features of normal pituitary gland, possibly as an autocrine or a paracrine regulator

Distribution, plasma concentration, and in vivo prolactin-releasing activity of peptide histidine methionine in humans.

The distribution of immunoreactive peptide histidine methionine (PHM) in human tissues and its plasma concentrations were examined using a specific RIA and gel filtration chromatography. The effects of synthetic PHM on anterior pituitary hormone secretion also were studied. Immunoreactive PHM was found in all tissues studied; high concentrations were found in the gastrointestinal tract, lung, and parotid gland. Subsequent but smaller amounts of PHM were found in the hypothalamus, pituitary stalk, olfactory lobe, and cerebral cortex. The distribution of immunoreactive PHM in human tissues was very similar to that of vasoactive intestinal polypeptide (VIP), and PHM and VIP were in equimolar concentrations. Immunoreactive PHM was also detectable in plasma of normal subjects, and similar plasma concentrations were found in patients with prolactinomas. Molecular sieve chromatography of extracts of nonneural tissues and plasma extracts revealed only one peak, eluting in the position of synthetic PHM. Two peaks of immunoreactive PHM were found in brain tissue; one coeluted with synthetic PHM, and the other eluted in the high mol wt region. Bolus injections of synthetic PHM significantly increased plasma PRL levels in a dose-dependent manner. However, PHM did not alter plasma GH, TSH, ACTH, LH, or FSH levels. These results indicate that PHM is distributed widely in human tissues, and posttranslational processing of the VIP-PHM precursor molecule may be different in different tissues. The finding of equimolar distributions of PHM and VIP is consistent with the notion that these two peptides are synthesized from a common precursor. The presence of immunoreactive PHM in human hypothalamic and pituitary stalk tissue and its specific in vivo PRL-releasing activity suggest that PHM may play an important role in the regulation of PRL secretion.

Immunoreactive corticotropin-releasing hormone present in human plasma may be derived from both hypothalamic and extrahypothalamic sources.

Immunoreactive CRH concentrations were determined in human plasma using an immunoaffinity chromatographic extraction procedure and sensitive RIA. Immunoreactive CRH was detectable in the plasma of all normal subjects (mean +/- SD, 6.2 +/- 2.4 pg/mL; n = 15). Basal (0800-1000 h) plasma immunoreactive CRH levels were significantly lower in patients with Cushing's syndrome due to adrenal (2.8 +/- 1.1 pg/mL; n = 4) or pituitary adenomas (2.9 +/- 0.8 pg/mL; n = 5), in patients with hypothalamic hypopituitarism (3.2 +/- 0.9 pg/mL; n = 5), and in glucocorticoid-treated patients (3.9 +/- 1.9 pg/mL, n = 8). Basal plasma CRH levels were also low in patients with acromegaly (2.8 +/- 0.8 pg/mL; n = 14) and insulin-treated diabetic patients whose pituitary-adrenal function was normal (3.6 +/- 1.0 pg/mL; n = 12). In normal subjects plasma CRH levels increased after insulin-induced hypoglycemia; this response was abolished by the prior administration of dexamethasone. In contrast, basal plasma CRH levels were not affected by prior administration of metyrapone or dexamethasone. No evidence for diurnal variation in plasma immunoreactive CRH was found in normal subjects. In addition, in normal subjects oral glucose administration elicited a significant increase in plasma CRH (basal, 7.3 +/- 0.9 pg/mL; peak 30 min after glucose, 16.7 +/- 5.8 pg/mL; n = 5; P less than 0.05) without concomitant changes in ACTH. Gel filtration of extracts of pooled plasma from normal subjects revealed a major component of immunoreactive CRH in the position of synthetic rat CRH. Immunoreactive CRH-sized material had the same retention time as authentic rat CRH in a reverse phase high pressure liquid chromatography system. The content of immunoreactive CRH in human placenta, pancreas, and adrenal gland was much larger than that in hypothalamus. These findings suggest that immunoreactive CRH is present in peripheral plasma; the increase in plasma immunoreactive CRH after insulin-induced hypoglycemia may reflect stimulation of hypothalamic CRH release; the increase in plasma immunoreactive CRH after glucose administration may reflect extrahypothalamic CRH release; and the lack of diurnal variation in plasma immunoreactive CRH together with the lack of suppression of CRH by dexamethasone suggest that basal plasma CRH is of extrahypothalamic origin.

Selective 8-hydroxyguanine formation in pancreatic DNA due to a single intravenous administration of 4-hydroxyaminoquinoline 1-oxide in rats.

8-Hydroxyguanine (8-OHG) formation, a possible initiating event, was determined in pancreatic and liver DNA and compared with the genesis of acinar cell and hepatocyte necrosis in male Wistar rats given a single intravenous administration of 4-hydroxyaminoquinoline 1-oxide (4-HAQO). At the non-necrotic but tumorigenic dose of 7.0 mg/kg body weight, 8-OHG was selectively generated in pancreatic DNA, in the absence of acinar cell necrosis, at the 6 and 24 h time points and repaired by the 48 h time point. When rats were exposed to 4-HAQO at a necrotic dose of 14.0 mg/kg body weight, 8-OHG was also selectively formed in pancreatic DNA with the same time-dependence of generation and repair, while acinar cell necrosis became evident at the 24 h time point and progressed thereafter. Whereas no hepatocyte necrosis was detected in any rats, 8-OHG values for liver DNA merely expressed slight increases only at the 24 and 48 h time points in rats given 14.0 mg/kg body weight of 4-HAQO. The present data suggest that formation of oxidative DNA damage, assayed by 8-OHG, in pancreatic DNA is independent from toxicity and may be involved, along with quinoline adducts, in mutational events underlying 4-HAQO-induced rat acinar cell carcinogenesis.

Differential screening of ovarian cDNA libraries detected the expression of the porcine collagenase inhibitor gene in functional corpora lutea.

cDNA libraries were constructed from porcine granulosa cells of antral follicles as well as functional corpus luteum, and clones encoding stage-specific genes have been isolated by differential screening. A clone specific to the functional stage of corpus luteum was found to encode the porcine collagenase inhibitor gene and the stage-specific expression in luteinizing tissue was confirmed by Northern blot analysis. The complete open reading frame of the porcine collagenase inhibitor was deduced from the nucleotide sequence, and the localization of the product was examined by immunohistochemical staining as well in pig ovary; the inhibitor was detected in the intercellular space of luteal cells and in the connective tissue around blood vessels in the functional corpus luteum.

Expression of adrenomedullin and adrenomedullin mRNA in ectopic ACTH-secreting tumors.

OBJECTIVE: To study the expression of adrenomedullin, a potent vasodilator peptide originally isolated from a pheochromocytoma, in ectopic ACTH-secreting tumors. METHODS: Tumor tissue concentrations of adrenomedullin, calcitonin gene-related peptide, neuropeptide Y, endothelin-1, corticotropin-releasing hormone and ACTH were measured in three ectopic ACTH-secreting tumors by RIA. The expression of adrenomedullin mRNA was examined by northern blot analysis of tissue from one of the tumors. RESULTS: Immunoreactive adrenomedullin was detected in tumor tissues of three ectopic ACTH-secreting tumors (0.60-18.5 pmol/g wet weight). Calcitonin gene-related peptide, neuropeptide Y, endothelin-1 and corticotropin-releasing hormone were also detected in the tumor tissues. The tumor tissue concentrations of immunoreactive adrenomedullin were comparable to those of these four peptides, but much lower than those of ACTH. Northern blot analysis showed the expression of adrenomedullin mRNA in one tumor from which sufficient tissue was available for such study. The plasma concentration of immunoreactive adrenomedullin was increased in one patient (41.3 pmol/l, control 13.5 +/- 3.6 pmol/l, mean +/- S.D., n = 12). CONCLUSIONS: These results suggest that adrenomedullin is produced by ectopic ACTH-secreting tumors, together with other neuropeptides, and raise the possibility that adrenomedullin is related to the pathophysiology of these tumors.

Hepatic alveolar echinococcosis invading pancreas, vertebrae, and spinal cord.

A case of hepatic alveolor echinococcosis with contiguous invasion of the pancreas, vertebrae, and spinal cord and intrathecal metastases to the brain stem is reported. The long course after a hemihepatectomy may be a factor in the modification of the natural course of the disease and in the induction of this unusual mode of spread.

Effects of tetracyclines on neutrophil, gingival, and salivary collagenases. A functional and western-blot assessment with special reference to their cellular sources in periodontal diseases.

The characterization and regulation of matrix metalloproteinases (MMPs) have been studied to determine their role(s) in periodontal tissue destruction. Progress in elucidating the roles of MMPs in periodontal tissue destruction has led to a new concept involving the chemotherapeutic inhibition on MMPs, a therapeutic strategy which less than a decade ago was considered "a difficult and perhaps impossible task." Tetracyclines/doxycycline (DOXY) and their chemically modified nonantimicrobial derivatives (CMTs) are known to inhibit the matrix metalloproteinases, especially preferring human neutrophil collagenase (MMP-8), and prevent the oxidative activation of procollagenases. We characterized by Western blotting the molecular forms and cellular sources of gingival tissue, dental plaque, gingival crevicular fluid (GCF), and salivary MMPs associated with periodontitis. Also the molecular forms of tissue inhibitors of matrix metalloproteinases (TIMP-1 and TIMP-2) in periodontitis were studied by Western blot. Neutrophil (PMN)-derived MMPs were found to predominate in periodontitis, and phospholipase C present in increased amounts in periodontitis sites was found to be a potential inducer of PMN degranulation. We further studied the effects of DOXY on molecular forms of different latent and active MMPs purified from different cellular sources (PMNs, fibroblasts, keratinocytes) and present in vivo in oral exudates (gingival extracts, GCF, and saliva). DOXY inhibition of activated (oxidatively or proteolytically) MMPs were not associated with MMP fragmentation. Michaelis-Menten plots of initial rates of degradation of soluble type I collagen revealed an apparent Km value of 0.3-0.6 microM for MMP-8, and 75 microM DOXY inhibited MMP-8 in a manner which did not result in changes in apparent Km value but did prevent the initial degradation reaching Vmax providing evidence for noncompetitive inhibition. Treatment of patients with long-term DOXY medication results in decreased MMP-8 activities/levels in gingival tissue, crevicular fluid, and saliva, but not fragmentation of MMP-8 in vivo. These data further support and extend the key role of PMN-MMPs in periodontitis, and the activities of these PMN MMPs can be inhibited directly by therapeutic levels of DOXY.

Hyperprolactinemic recurrent miscarriage and results of randomized bromocriptine treatment trials.

OBJECTIVE: To evaluate hyperprolactinemia in the pathogenesis of recurrent spontaneous abortion. DESIGN: Randomized trial. SETTING: Miscarriage clinic, Yokohama City University Hospital, Yokohama, Japan. PATIENT(S): From a group of 352 women with recurrent spontaneous abortion, we identified 64 patients with a prolactin disorder that was not associated with any other etiologic abnormalities, including ovarian or endocrinologic disturbances such as luteal phase dysfunction, polycystic ovaries, hypersecretion of LH, galactorrhea, or thyroid hormone disorders. INTERVENTION(S): Restoration of prolactin levels with bromocriptine. MAIN OUTCOME MEASURE(S): Successful pregnancy (live birth). RESULT(S): The percentage of successful pregnancies was higher in the bromocriptine-treated group than in the group that was not treated with bromocriptine (85.7% versus 52.4%, P < .05). Serum prolactin levels during early pregnancy (5-10 weeks of gestation) were significantly higher in patients who miscarried (31.8-55.3 ng/mL) than in patients whose pregnancies were successful (4.6-15.5 ng/mL, P < .01 or P < .05). CONCLUSION(S): Appropriate circulating levels of prolactin may play an important role in maintaining early pregnancy, especially in cases of hyperprolactinemic recurrent miscarriage.

Immuno-inflammatory responses in the tissue adjacent to titanium miniplates used in the treatment of mandibular fractures.

The immuno-inflammatory responses to titanium miniplates used in the treatment of mandibular fractures were studied immunohistochemically at light and electron microscope levels. Titanium miniplates were stably situated on the cortical bone surface. In the soft tissue adjacent to the surface of titanium miniplates, double layered connective tissue was observed, which consisted of dense fibrous connective tissue, and relatively loos connective tissue contained proliferated blood vessels with hypertrophied endothelial cells. These vascular endothelial cells expressed HLA-DR, CD54 and CD62P antigens. In some cases they were CD62Epositive. CD68+ and CD11c+ round or spindle-shaped macrophages had infiltrated around the small vessels. Fine titanium particles were observed in the cytoplasm of these macrophages. Both CD4+ and CD8+ T lymphocytes had also infiltrated around venules in some cases. They were CD4+ T lymphocyte-dominant. Immunoelectron microscopically, CD68+ and CD11c+ macrophages contained titanium particles in the lysosomes. Most of the macrophages showed varying degrees of degenerative change. The presence of titanium was confirmed by energy-dispersive X-ray analysis.

Leiomyoma of the mandible: a rapid growing case with immunohistochemical and electron microscopic observations.

A rare case of leiomyoma of the mandible is reported together with the conventional histologic, immunohistochemical, and electron microscopic findings. On immunohistochemical evaluation the tumor cells were positive for vimentin, desmin, and alpha-smooth muscle actin but negative for neurogenic antigens and markers for vascular endothelial cells. Ultrastructural examination revealed smooth muscle cell differentiation. The Ki-67 labeling index was 4.7%. The tumor showed rapid increase in size and clinical features suggestive of malignancy. However, on histopathologic evaluation it was diagnosed as a benign neoplasm, and this diagnosis was supported by the results for mitotic rate, Ki-67 labeling index, and p53 immunostaining.

Intraoral reconstruction with innervated forearm flap: a comparison of sensibility and reinnervation in innervated versus noninnervated forearm flap.

OBJECTIVE: To evaluate the cutaneous sensibility and sensory reinnervation in patients who underwent intraoral reconstruction with an innervated or noninnervated forearm flap. STUDY DESIGN: Results of the use of innervated forearm flaps in oral reconstruction was compared with the use of noninnervated flaps. The evaluation of sensibility and reinnervation comprised clinical sensibility tests and immunohistochemical investigation of postoperative biopsy specimens against S-100 and neurofilament. RESULTS: The innervated flaps (4 patients) provided earlier and qualitatively better recovery of sensation than the noninnervated flaps (9 patients). Immunohistochemical investigation revealed the existence of a larger number of regularly arranged sensory nerve fibers in the cutaneous tissue of the innervated flaps than in the noninnervated flaps. Examination with an electron microscope found the structure of these nerve fibers to be well preserved in the innervated flaps, whereas nerve fibers in the noninnervated flaps were degenerative. CONCLUSION: These findings suggest (1) that the innervated flaps are superior to the noninnervated flaps not only for the repair of defects but also for the restoration of function and (2) that the innervated flaps contribute to the improvement of the quality of life for patients.

Inhibitory effects of N,N'-diphenyl-p-phenylenediamine on the early stage of the enhanced hepatocarcinogenesis caused by coadministration of ethionine and a choline-deficient L-amino acid-defined diet in rats.

Effects of N,N'-diphenyl-p-phenylenediamine (DPPD), an antioxidant, on liver carcinogenesis caused by a choline-deficient L-amino acid-defined (CDAA) diet containing ethionine were studied in Fischer 344 rats. Male animals, 6 weeks old, were fed a CDAA diet, a choline-supplemented L-amino acid-defined (CSAA) diet or a CDAA diet containing 0.05% ethionine with or without 0.2% DPPD. Histological changes and lesions positive for gamma-glutamyltransferase (GGT) were analyzed 12 weeks after the beginning of the experiment. The levels of 8-hydroxyguanine (8-OHGua) in DNA and 2-thiobarbituric acid-reacting substances (TBARS) were measured as the parameters for cellular oxidative damage after 4 and 11 days of treatment. Expression of c-myc and c-Ha-ras was also investigated in relation to cell proliferation after 2, 4, 8 and 11 days. Histologically, development of diffuse fatty liver observed in rats fed a CDAA diet was inhibited, while massive oval cell proliferation and cholangiofibrosis resulted from the addition of ethionine with/without DPPD. The sizes but not numbers of GGT-positive lesions seen in the liver of rats fed a CDAA diet were increased and the levels of 8-OHGua formation and TBARS generation were also increased by the ethionine supplement. Both numbers and sizes of GGT-positive lesions were decreased and the level of TBARS, but not 8-OHGua, was decreased by adding DPPD. The increased expression of c-myc and c-Ha-ras detected in the liver of rats fed a CDAA diet was further increased by addition of ethionine and again reduced by DPPD. These results indicate that an antioxidant DPPD can inhibit the early stage of enhanced hepatocarcinogenesis caused by coadministration of ethionine and a CDAA diet, by blocking cellular oxidative damage as well as c-myc and c-Ha-ras expression.

Precancerous lesions of the gallbladder mucosa.

To elucidate the morphological characteristics and the incidence of precancerous lesions of the gallbladder, 200 gallbladders removed for presumed benign diseases were examined histopathologically. Dysplastic epithelia with distinct cellular and structural atypia were graded into either mild or moderate to severe degree. Twenty-nine (14.5%) of 200 cases showed dysplasia; 5 (2.5%) was to moderate to severe degree and 24 (12%) to mild degree. Carcinoma in situ was found in 4 cases (2%) and occult invasive carcinoma in 2 cases (1%). Simple hyperplasia was seen in 54 cases (27%). Abnormal epithelia showed a male preponderance in consistent with the previous report on cancer epidemiology in Japan. Dysplasia and hyperplasia were found to have close association with chronic cholecystitis, but not with gallstones per se. It was postulated that the progression of dysplasia or carcinoma in situ into invasive carcinoma may occur in the sixties to seventies.

Effects of beta-carotene and alpha-tocopherol on rumen bacteria in the utilization of long-chain fatty acids and cellulose.

Addition of safflower oil to a growth medium depressed the growth of mixed rumen bacteria above 200 mg/L and did not significantly increase bacteria, even at lower concentrations. However, when 10 mg/L of beta-carotene were added to 50 to 100 mg/L of safflower oil, bacterial growth was significantly increased. When more than 200 mg/L of safflower oil were present, beta-carotene markedly restored the growth capacity. alpha-Tocopherol was more effective than beta-carotene, although it inhibited growth at high concentrations. The combination of beta-carotene and alpha-tocopherol (each 5 mg/L) exerted partially additive effects. beta-Carotene plus alpha-tocopherol enhanced bacterial cell yield in the presence of safflower oil, caprate, stearate, or linoleate, suggesting that beta-carotene and alpha-tocopherol increase the utilization of fatty acids. beta-Carotene plus alpha-tocopherol also stimulated cellulose digestion in the presence of 100 mg/L of safflower oil, evidently through the increased growth of cellulolytic bacteria.