Corneal epithelial toxic effects and inflammatory response to perfluorocarbon liquid

We report an unusual case of corneal epithelial toxic effects associated with perfluorocarbon liquids (PFCLs). The clinical and histopathologic findings are described. An elderly man underwent vitreoretinal surgery for a complicated retinal detachment. Perfluorodecalin was used to repair the retina. It was left in situ for 8 weeks and removed via the pars plana. One month after removal of heavy liquids the patient developed a nonhealing corneal epithelial defect associated with limbitis. Perfluorodecalin was found under the superior conjunctiva. A conjunctival biopsy revealed the presence of vacuoles in the conjunctival stroma surrounded by an inflammatory response that consisted of lymphocytes, macrophages, and giant cells. On surgical removal of the PFCL from the subconjunctival space, the epithelial defect healed. The histopathologic and clinical evidence suggest that the inflammatory response and corneal epithelial ulceration were caused by the prolonged presence of PFCL in the subconjunctival space. To the best of our knowledge, PFCLs have not previously been reported to cause corneal epithelial defects or incite an inflammatory response in the human eye.

Spermatogenesis without gonadotropins: maintenance has a lower testosterone threshold than initiation

We showed previously that testosterone (T) alone could induce spermatogenesis and produce normally fertile spermatozoa in the absence of circulating gonadotropins. These studies used the hpg mouse, which is characterized by a congenital gonadotrophin deficiency due to a major deletion in the GnRH gene. Administering T by a subdermal implant of a SILASTIC brand tube impregnated with crystalline T showed that the androgenic requirement for full induction of spermatogenesis was a 1-cm length implant. Using this unique model of spermatogenesis without gonadotropins, we have now investigated the quantitative requirement for androgens to maintain spermatogenesis by testing the hypothesis that the androgenic threshold required for induction and maintenance of spermatogenesis are the same. Spermatogenesis was induced in homozygous hpg mice by T administration for 6 weeks. The first experiment determined the time-course of the regression of spermatogenesis after removal of the T-impregnated SILASTIC brand implant. Elongated spermatids were absent by 3 weeks and testicular weight regression was maximal by 4 weeks after androgen withdrawal. The second experiment examined the effects on maintenance of spermatogenesis of reducing the T dose. After full induction of spermatogenesis in homozygous hpg mice, the T implants were replaced with a range of smaller size T-impregnated SILASTIC brand implants for a further 4 weeks. All androgen-sensitive end-points (testis weight, tubular, and luminal diameters, round spermatids) were fully maintained with T implants of 0.06 cm and elongated spermatids with T implants of 0.25 cm. A further experiment showed that at very low T doses (0.06, 0.125 cm) the T effects observed at 4 weeks were maintained at 6 and 11 weeks duration. We conclude that the androgenic threshold to maintain spermatogenesis in the mouse is an order of magnitude lower than the threshold required for inducing spermatogenesis. This distinction suggests that the mechanism of action of testosterone in inducing spermatogenesis may involve regulation of a genetic switch to complete meiosis, whereas the maintenance involves a different locus of action. These findings suggest that further studies of androgen-dependent meiotic genes may be central to understanding the regulation and molecular basis of androgen-driven induction and maintenance of spermatogenesis.

Role of neurotrophin-trk interactions in oncology: the anti-tumor efficacy of potent and selective trk tyrosine kinase inhibitors in pre-clinical tumor models

The increasing knowledge of the pathogenic mechanisms involved in cancer cell growth has enabled the implementation of mechanism based drug design approaches rather than the more conventional nonspecific approaches. Drugs that interfere with cellular signal transduction pathways are currently a major focus in development of newer therapeutic technologies in oncology. The therapeutic utility of potent and selective tyrosine kinase inhibitors in oncologic applications has become widely recognized for several years, however targeting neurotrophin receptors as a molecular target driven approach has only recently been realized. This review presents the hypothesis of the neurotrophin-trk receptors as a viable molecular target for medicinal chemical intervention in tumor biology, followed by an overview of the pre-clinical studies which culminated in the advancement of the first potent trk tyrosine kinase inhibitor CEP-2563 (KT-8391), and the orally active K-252a analog, CEP-701 (KT-5555) into clinical evaluation.

Expression of core 2 beta-1,6-N-acetylglucosaminyltransferase in a human pancreatic cancer cell line results in altered expression of MUC1 tumor-associated epitopes

Many tumor-associated epitopes possess carbohydrate as a key component, and thus changes in the activity of glycosyltransferases could play a role in generating these epitopes. In this report we describe the stable transfection of a human pancreatic adenocarcinoma cell line, Panc1-MUC1, with the cDNA for mucin core 2 GlcNAc-transferase (C2GnT), which creates the core 2 beta-1,6 branch in mucin-type glycans. These cells lack endogenous C2GnT activity but express a recombinant human MUC1 cDNA. C2GnT-transfected clones expressing different levels of C2GnT were characterized using monoclonal antibodies CC49, CSLEX-1, and SM-3, which recognize tumor-associated epitopes. Increased C2GnT expression led to greatly diminished expression of the CC49 epitope, which we identified as NeuAcalpha2,6(Galbeta1,3)GalNAcalpha-Ser/Thr in the Panc1-MUC1 cells. This was accompanied by the emergence of the CSLEX-1 epitope, sialyl Lewis x (NeuAcalpha2,3Galbeta1,4(Fucalpha1,3)GlcNAc-R), an important selectin ligand. Despite this, however, the C2GnT transfectants could not bind to selectins. Increased C2GnT expression also led to masking of the SM-3 peptide epitope, which persisted after the removal of sialic acid, further suggesting greater complexity of the core 2-associated O-glycans on MUC1. The results of this study suggest that C2GnT could play a regulatory role in the expression of certain tumor-associated epitopes.

Patient attitudes and preferences regarding treatment: GH therapy for childhood short stature

This paper examines the role of parents' attitudes and preferences regarding growth hormone therapy for childhood short stature. Four main questions are addressed. First, what are the demographic characteristics of families seeking medical advice for their child's short stature? Second, what are parents' attitudes towards short stature? Third, what are parents' treatment preferences (i.e. what characteristics of growth treatments are important to parents)? Finally, how do the attitudes of parents affect physician decision making? Several studies are reviewed and data are presented to answer these questions.

Active immunization against follistatin and its effect on FSH, follicle development and superovulation in heifers

Ovaries of heifers were examined daily by transrectal ultrasonography for one interovulatory interval before initiation of immunizations (control cycle, n = 14), and again after the fifth immunization with a sham-vaccine (Freund's adjuvant only; n = 7) or a recombinant porcine follistatin-vaccine (1 mg per vaccination; n = 7) to study the effect of follistatin on follicle dynamics. After the fifth immunization, 4 heifers had a follistatin antibody titer of > or = 1:3200, while the remaining 3 heifers had a titer of only 1:400. At wave emergence, the total number of follicles and the number of small follicles (3 to 5 mm) were higher (P < 0.05) in the follistatin group than in the control and sham groups. In addition, high-titer heifers had a greater (P < 0.05) number of follicles (total and small) per day than low-titer heifers. Plasma concentration of FSH remained unchanged after sham- or follistatin-immunization. Sham- and follistatin-vaccinated heifers were then given half the standard superovulatory dose of Folltropin (200 mg of FSH) 14 d after the sixth immunization. More ovulations were detected in follistatin- (10.9 +/- 2.4) than sham- (5.0 +/- 0.8) vaccinated heifers (P < 0.05). Moreover, heifers with a high titer had more ovulations (P < 0.02) than heifers with a low titer (15.0 +/- 2.5 vs 5.3 +/- 1.2). The number of ova-embryos classified as fertilized:unfertilized and transferable:discarded, and quality of the embryos were similar between sham and follistatin groups. By 80 d after the last immunization, when antibody titers were undetectable in the follistatin group, there was no difference in superovulatory response between sham (6.7 +/- 1.6) and follistatin (7.6 +/- 1.6) groups. In summary, follistatin immunization was associated with an increase in the number of small follicles at the time of wave emergence and a greater response to superovulatory treatment. The results suggest that effects of follistatin on follicular dynamics were not mediated through changes in pituitary secretion of FSH.

Morphometric studies of neonatal estrogen imprinting in the mature mouse prostate

Estrogens play an important role in prostate physiology and neonatal exposure to estrogens has profound effects on the mature structure and hormonal sensitivity of rodent prostate. We aimed to determine the long-term effects of neonatal estrogens on the ductal architecture, morphology and hormonal sensitivity of the mature mouse prostate. Newborn mice (day 1-2) were administered a single injection (s.c.) of estrogens (estradiol benzoate (EB), diethylstilbestrol (DES)) with or without concomitant anti-estrogens (tamoxifen (TAM) or ICI 182 780 (ICI)) TAM or ICI alone, GnRH-antagonist (GnRH-A) or vehicle. At 7 weeks of age, ventral prostates (VP) were microdissected to estimate branch tip numbers and processed for stereologic analysis of volume fractions and diameters of various tissue components. Estrogens induced permanently reduced branching morphogenesis leading to reduced VP weights and these effects were fully reproduced by GnRH-A, consistent with an indirect effect. Stereologically, neonatal estrogens induced epithelial and stromal hyperplasia and significantly reduced (P<0.05) the diameters of VP glandular tubules and lumen compared with controls and these regressive effects were not reversed either by TAM or ICI. These studies confirm that a single neonatal dose of both DES and EB produces imprinting in the mature mouse prostate and indicate that neonatal estrogen effects involve both direct as well as indirect effects. In addition, both TAM and ICI act as partial agonists to the estrogen receptor in the ventral prostate of neonatal mouse.

Collection of peripheral blood stem cells after a preceding autograft: unfavorable effect of prior interferon-alpha therapy

Eighty-eight previously autografted (78 transplanted twice and 10 once) myeloma patients who had no cryopreserved stem cells available for possible future use received G-CSF for mobilization of stem cells. One-fourth of the patients had progressive disease at the time of apheresis. All patients had received 200 mg/m2 melphalan for the first transplant. The interval between the preceding transplant and the harvest was 5-68 months (median 29). A total of 0.46-9.16 (median 3.03) x 10(6) CD34+ cells/kg were collected. More than 2 x 10(6)/kg CD34+ cells were collected in 76% of the patients, and > or = 5 x 10(6)/kg in 14%. On multivariate analysis, patients with platelet counts of > or = 200 x 10(9)/l (P < 0.0001), those who had not received any myelosuppressive chemotherapy between the last transplant and the collection (P = 0.02), and those who had received interferon-alpha for < or = 6 months (P = 0.03) had better collections. Eleven of 12 patients autografted with these cells had prompt neutrophil recovery (median 10 days to 0.5 x 10(9)/l) but recovery to 50 x 10(9)/l platelets was delayed or incomplete in 11 of 12. We conclude that it is possible to harvest peripheral blood stem cells with G-CSF stimulation in patients who have been autografted previously. Limited data suggest that platelet recovery may be suboptimal when these cells are used. These findings have practical implications for patients with malignant diseases in remission after autografting who may be candidates for future salvage therapy but have no stem cells stored, and for patients with chronic myeloid leukemia who are on long-term interferon-alpha therapy to attain cytogenetic remission for eventual collection of normal stem cells.

Imprinting by neonatal sex steroids on the structure and function of the mature mouse prostate

Perinatal sex-steroid exposure may result in permanent modifications in the structure and function of the prostate gland. The mechanism of such long-range alterations in hormonal sensitivity is not known. This study aimed to define the molecular requirements for neonatal sex-steroid imprinting and to investigate whether combined administration of neonatal androgens and estrogens had synergistic effects upon the mature mouse prostate. Since the interaction between endogenous and exogenous sex steroids in normal mice makes it difficult to dissociate direct from indirect effects, we used the hypogonadal (hpg) mouse, characterized by congenital androgen deficiency yet still fully responsive to exogenous androgens. Newborn mice (Days 1-2) were administered a single s.c. injection of androgens alone or in combination with an estrogen followed by testosterone-induced maximal prostate growth at maturity. The final effects were determined in 7-wk-old mice through study of ductal architecture in microdissected ventral prostates (VP) and quantitation of volume densities and diameters of prostate tissue components. A single neonatal dose of androgens, but not of estrogen, increased branching morphogenesis and VP weights at adulthood. These effects did not differ significantly between various androgens; in addition, combined androgen and estrogen treatment failed to demonstrate any synergistic effects on the prostate. We conclude that neonatal androgens induce long-range effects upon the mature VP structure as well as its secretory function and that this imprinting occurs via the androgen receptor without requiring aromatization of androgens. However, these conclusions, based on a specific treatment protocol, are confined only to the distal segment of VP, and effects of neonatal sex-steroid exposure in other regions or lobes of VP may differ.

Divalent cations stabilize the alpha 1 beta 1 integrin I domain

Recent structural and functional analyses of alpha integrin subunit I domains implicate a region in cation and ligand binding referred to as the metal ion-dependent adhesion site (MIDAS). Although the molecular interactions between Mn2+ and Mg2+ and the MIDAS region have been defined by crystallographic analyses, the role of cation in I domain function is not well understood. Recombinant alpha 1 beta 1 integrin I domain (alpha1-I domain) binds collagen in a cation-dependent manner. We have generated and characterized a panel of antibodies directed against the alpha1-I domain, and selected one (AJH10) that blocks alpha 1 beta 1 integrin function for further study. The epitope of AJH10 was localized within the loop between the alpha 3 and alpha 4 helices which contributes one of the metal coordination sites of the MIDAS structure. Kinetic analyses of antibody binding to the I domain demonstrate that divalent cation is required to stabilize the epitope. Denaturation experiments demonstrate that cation has a dramatic effect on the stabilization of the I domain structure. Mn2+ shifts the point at which the I domain denatures from 3.4 to 6.3 M urea in the presence of the denaturant, and from 49.5 to 58.6 degrees C following thermal denaturation. The structural stability provided to the alpha1-I domain by divalent cations may contribute to augmented ligand binding that occurs in the presence of these cations.

High-dose therapy with autologous haemopoietic stem cell support for Waldenström's macroglobulinaemia

Standard doses of alkylating agents or purine analogues effect response rates of up to 50% in Waldenström's macroglobulinaemia (WM); however, complete responses are infrequent and there are no cures. We have evaluated the feasibility, safety and efficacy of high-dose chemotherapy with peripheral blood stem cell support in six patients aged 45-69 years (median 51.5) with WM; four patients relapsed after prior therapy inclusive of purine analogues and two patients proceeded with transplant after minimal therapy. Four patients mobilized adequate numbers of stem cells; however, two patients with more extensive fludarabine therapy failed to mobilize and required a second attempt at stem cell collection. Five patients were treated with melphalan 200 mg/m2, including one patient who received tandem transplants and one patient who received melphalan 140 mg/m2 with added total body irradiation (TBI). There was no treatment-related mortality and non-haematological toxicities were manageable. Engraftment was prompt except in one patient with extensive prior use of fludarabine. All the six patients achieved at least partial response (PR), including one who achieved complete response (CR). Five patients are alive and four are event-free at 52+, 15+, 12+ and 2+ months post transplant. This pilot study suggests safety and efficacy of high-dose therapy in WM and suggests that the peripheral blood stem cells should preferably be procured prior to extensive use of purine analogues.

Transdermal iontophoretic delivery of bovine insulin and monomeric human insulin analogue

The present study was undertaken to explore the possibility of delivering bovine insulin in streptozocin (STZ)-induced diabetic rats by iontophoresis. Further, the effect of iontophoresis of monomeric human insulin analogue (r-DNA origin) on the plasma glucose level (PGL) of diabetic rats was studied. Iontophoresis of bovine insulin (10-200 IU/ml) was not effective in decreasing the PGL in untreated diabetic rats. Pretreatment of skin with oleic acid or menthol for 3 h followed by iontophoresis of bovine insulin also failed to produce a fall in PGL. Application of a depilatory cream for hair removal (24 h before the experiment), followed by iontophoresis of bovine insulin (10, 30 and 100 IU/ml) produced a concentration-dependent fall in PGL. Further, application of depilatory cream immediately before the experiment produced a substantial fall in PGL both by passive diffusion and iontophoresis. Depilatory cream might have drastically reduced the barrier function of skin such that conventional bovine insulin (dimer and hexamer) penetrates through the intact skin by iontophoresis and even by passive diffusion. Depilatory cream or the active components of depilatory cream may be useful as penetration enhancers for transdermal delivery of drugs especially macromolecules such as insulin. Iontophoresis of monomeric human insulin analogue (B9 Asp, B27 Glu) through intact skin (untreated) produced a significant fall in PGL in diabetic rats. Monomeric human insulin analogues which have low tendency to self aggregation may be promising candidates for the transdermal iontophoretic delivery of insulin.

The measurement of nitrite in adulterated urine samples by high-performance ion chromatography

With the increased availability of nitrite-containing commercial products that are used for the adulteration of urine samples in the workplace, it is necessary for laboratories to be able to detect and confirm the presence of nitrite in these samples. We have developed a method to confirm the presence of nitrite in urine samples. The method uses the IonPac AS 14 analytical column with the Dionex series 45001 Bio LC system equipped with an anion self-generating suppressor and conductivity detector. Using a single-point calibration, the method is linear and accurately quantitates nitrite to 12,000 microg/mL. The limit of detection is 30 microg/mL, and the day-to-day precision of the assay has a coefficient of variation (CV) of 4.3% at 1200 microg/mL and 3.8% at 2700 microg/mL of nitrite.

Effect of ethanol/propylene glycol on the in vitro percutaneous absorption of aspirin, biophysical changes and macroscopic barrier properties of the skin

The effect of the solvent systems ethanol (EtOH), propylene glycol (PG) and combinations thereof was examined on the in vitro percutaneous absorption of the antithrombotic, aspirin, through porcine epidermis. Biophysical changes in the stratum corneum lipids were studied through the use of Fourier transform infrared (FTIR) spectroscopy. Macroscopic barrier properties of the epidermis were examined through the use of in vitro transepidermal water loss (TEWL). The flux of aspirin increased with increasing concentrations of EtOH in the solvent systems. The maximum flux of aspirin was achieved by 80% EtOH in combination with 20% PG beyond which (i.e. 100% EtOH) there was no increase in the flux. FTIR spectroscopic study was enacted in order to determine the biophysical properties of the stratum corneum when the solvents were applied. The FTIR spectra of the stratum corneum treated with 80% EtOH/20% PG showed a maximum decrease in absorbance for the asymmetric and symmetric C&z. sbnd;H peaks, which suggests a greater loss of the lipids in the stratum corneum layers. In vitro TEWL studies allowed an investigation into the macroscopic barrier integrity properties of the stratum corneum. The TEWL results indicated that each of the solvent systems significantly enhanced (P<0.05) in vitro TEWL in comparison to the control. In conclusion, 80% EtOH/20% PG enhanced the percutaneous absorption of aspirin by perturbing the macroscopic barrier integrity of the stratum corneum and through a loss of stratum corneum lipids.

Effect of linolenic acid/ethanol or limonene/ethanol and iontophoresis on the in vitro percutaneous absorption of LHRH and ultrastructure of human epidermis

The effect of enhancer(s) (e.g. ethanol (EtOH), 5% linolenic acid/EtOH, and 5% limonene/EtOH) and iontophoresis was investigated on the in vitro percutaneous absorption of luteinizing hormone releasing hormone (LHRH) and ultrastructure of human epidermis by transmission electron microscopy (TEM). 5% linolenic acid/EtOH or 5% limonene/EtOH significantly enhanced (P<0.05) the passive flux of LHRH through human epidermis in comparison to the control (no enhancer treated epidermis). Iontophoresis further increased the flux of LHRH through enhancer(s) treated epidermis. Iontophoretic flux of LHRH through 5% linolenic acid/EtOH and 5% limonene/EtOH treated epidermis was significantly (P<0.05) enhanced in comparison to iontophoretic flux through the control epidermis. TEM is the most efficient way to visualize the ultrastructure of the stratum corneum (SC). TEM results reveal that iontophoresis in combination with enhancers (e.g. linolenic acid/EtOH or and limonene/EtOH) transformed the highly compact cells of the SC into a looser network of filaments, disrupted the keratin pattern, and resulted in swelling of SC cell layers of human epidermis. Thus, linolenic acid/EtOH or limonene/EtOH in combination with iontophoresis increased the flux of LHRH through human epidermis by disrupting keratin pattern as well as loosening and swelling of SC cell layers.

Induction of NADPH diaphorase/nitric oxide synthase in the spinal cord motor neurons of rats following a single and multiple non-penetrative blasts

The present study has demonstrated the induction of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) reactivity and nitric oxide synthase-like immunoreactivity (NOS-LI) in the ventral horn motoneurons of the spinal cord in rats subjected to a single or multiple underground, or a single surface blast. Both enzyme activities were first detected in some motoneurons in laminae VIII and IX of Rexed, 3 hours after the blast. Some NADPH-d and NOS-LI positive neurons were also distributed in laminae VI and VII. The number and intensity of the labelled cells appeared to increase progressively, peaking at 2-3 days after the blast but were drastically reduced thereafter, so that at 7 days after the blast only a few positive neurons were observed. In rats killed at 2 weeks and in longer surviving intervals, i.e. up to 1 month, NADPH-d/NOS reactivity in the ventral horn motor neurons had diminished. The functional significance of the transient expression of neuronal NADPH-d/NOS after the blasts remains uncertain, although from a speculative point of view, the induction of these enzymes probably would reflect an increased production of nitric oxide (NO). In view of the lack of atrophic changes in most, if not all, of motor neurons, it is suggested that the increased levels of NO production after the blast injury may be involved in a neuroprotective function.

Stereological evaluation of mouse prostate development

A stereological study of the development of the mouse prostate was undertaken between the second week of postnatal life and maturity. The aim was to quantify the progressive changes in the size and areal density of the ventral prostate gland components during development. Male mice were studied at weekly intervals from days of life 15 to 49 for organ and body weights, ductal branching, diameters of ventral prostate ducts and lumen and volume densities of epithelium, lumen, and stroma. Ductal branch-tip numbers were maximal at 35 days of age, while prostate weights increased linearly with age and did not reach a plateau at 49 days. Prostatic glandular and luminal diameters both showed a continuous increase until day 49. At 5 weeks of age, there was a decrease in the volume density of prostatic epithelium accompanied by a simultaneous increase in the volume density of the lumen. This study indicates that prostate-branching morphogenesis is complete by the fifth week in mice but that further growth of the prostate continues due to the increase in ductal dimensions. Qualitatively, the ventral prostate in mice is fully mature by 5 weeks, and this histological maturity coincides with the completion of branching morphogenesis.

State of pregnancy modifies lead toxicity in mice

Toxicity of lead acetate after administration through the oral route at 0-50 mg/kg body weight of animal has been assessed in the liver of pregnant mice and compared with the effect in the liver of nonpregnant dams. Analysis showed that the basal level of hepatic lead is considerably reduced during pregnancy as compared to that in nonpregnant state. After administration of Pb-acetate, deposited lead in liver of nonpregnant mice was 3- to 4-fold while in pregnant mice was, it was 1.8- to 3.0-fold over their respective control values. Although hepatic Fe, Cu, and Zn levels had a tendency to be lowered during pregnancy, it appeared that the added trace quantity of lead prior to and during pregnancy helped in the retention of these metals, which either remained unaffected (as Fe) or declined (Cu and Zn) after lead administration during the nonpregnant state. The effect of lead on Mn diminution, however, was visible at the dose of 50 mg/kg body wt of lead-acetate. Alkaline phosphatase, which increased during pregnancy along with Mn, was reversed between the pregnant and nonpregnant states after oral administration of lead. On the other hand, the level of delta-aminolevolunic acid dehydratase, which declined during normal pregnancy, continued to fall further after lead exposure. It is concluded that the distribution of basal or administered lead and its effect on enzyme activities and trace metal composition in liver depends on the pregnant and nonpregnant states of female hosts.

Inhibition by dietary menhaden oil of cyclooxygenase-1 and -2 in N-nitrosomethylurea-induced rat mammary tumors

Studies in laboratory animals and epidemiological surveys suggest a relationship between the type and amount of dietary fat and mammary cancer. One mechanism proposed to explain this relationship is modulation by dietary fat, of mammary tumor eicosanoid levels through action at the rate limiting enzyme in eicosanoid synthesis, cyclooxygenase (COX). Until recently there have been no studies which have examined COX gene expression in human breast or rodent mammary tissues. In this study we have demonstrated the presence of two immunoreactive isoforms of cyclooxygenase (COX-1 and -2), and the modulating effects of n-3 fatty acids on their expression, in N-nitrosomethylurea (NMU)-induced rat mammary tumors. Three different high fat diets were compared namely, corn oil (CO) 23%; CO 18% menhaden oil (MO) 5%; CO, 5%/MO 18%; low fat corn oil (5%) served as a control. It was found that immunoreactive COX-2 protein levels were approximately 3x higher than COX-1 levels in NMU-induced mammary tumors. Moreover, the high menhaden oil diet (rich in n-3 fatty acids) significantly suppressed both COX-1 (-28%) and COX-2 (-36%) protein levels when compared to the high corn oil diet. No differences were found among the other treatment groups when compared pair-wise or with low-fat control. The mechanism(s) by which n-3 fatty acids suppress COX-1 and COX-2 remain to be determined.

Evidence to suggest morphological and physiological alterations of lacrimal gland acini with ageing

This study investigates changes in the morphology and physiology of lacrimal gland acinar cells with age. Changes in microstructural appearance of the acinar cells, the type and distribution of the different acini in glands and the secretory granules within the acini were examined in glands from animals of 3-5, 9, 12, 20, 24 and 28 month old rats. Differences in the secretory capacity of the acinar cells were also examined in animals of each age-group, with the exception of 28 months. The typical acini of young glands (3-5 months) were of the serous type. This was also true of 9 month glands, although there was a significant reduction in their overall distribution compared to young glands. The acini in the 12 month glands were predominantly of the seromucous type and appeared to be at the expense of the serous acini which were further significantly reduced compared to 3-5 and 9 month glands. This remained the prevalent acini type in 20 month glands, however by 24 months there was a significant increase in the occurrence of mucous acini and this time appeared to be at the expense of the seromucous acini which were significantly reduced in glands of this age-group. The predominant acinar cell in 28 month glands, like 24 month glands, was of the mucous variety. Qualitative EM studies revealed a progressive change in the secretory products of the lacrimal gland acini, strongly correlating to changes in acinar cell type. Typical acini of both 3-5 and 9 month glands contained numerous protein secretory granules. The seromucous acini also of these age groups contained both protein and mucous secretory granules, with the protein secretory granules in higher abundance. By 12 months the typical seromucous acini was packed with both protein and mucous secretory granules of equal proportions. However, by 20 months the predominant seromucous acini contained fewer protein secretory granules and elevated occurrence of mucous secretory granules. By 24 and 28 months the acini contained even fewer protein secretory granules and the typical acinar cell was of the mucous type containing exclusively mucous secretory granules. The secretory capacity of the acini was also altered with age. Maximum protein output in response to cholinergic stimulation resulted in an initial significant increase with ageing from 3-5 months to 9 and 12 months followed by a later significant age-dependent reduction in output. However, maximal peroxidase release from acinar cells of 3-5 and 9 month glands was the same. This was followed by a significant age-dependent reduction in peroxidase release. Furthermore, the concentrations required to evoke these responses differed with age. These results present evidence to suggest that acinar cells of the lacrimal gland undergo progressive alterations with age. The type of acini changing initially from serous to seromucous acini (intermediate phase) followed by a gradual transformation of the seromucous acini to mucous acini. This in turn changes the properties of the acini from protein producing and secreting acini to mucous producing and secreting acini. The results also suggest a reduction in the ability of the acini to synthesise proteins with age and altered responsiveness to cholinergic stimulation to secrete proteins. These findings may help in explaining the occurrence of altered protein/tear secretion with ageing.

Interaction of islet hormones with cholecystokinin octapeptide-evoked secretory responses in the isolated pancreas of normal and diabetic rats

This study investigates the effects of the islet hormones, insulin (Ins), glucagon (Glu) and somatostatin (Som) with cholecystokinin octapeptide (CCK-8) on amylase secretion and intracellular free calcium concentration [Ca2+]i and their pattern of distribution in the isolated pancreas of normal and diabetic rats. Ins and Glu evoked small increases in amylase output from pancreatic segments compared with a much enhanced effect of CCK-8. In contrast, Som induced a biphasic response comprising an initial decrease followed by a secondary increase and this biphasic response may be dependent upon the concentration. Combining the islet hormones with CCK-8 resulted in marked potentiation in amylase output compared with either CCK-8 alone or the individual hormone. Genistein and tyrphostin A25, the tyrosine kinase inhibitors, evoked a small decrease in amylase output from pancreatic segments. They had no effect on the CCK-8-evoked secretory response but markedly inhibited the potentiation of the islet hormones with CCK-8. In pancreatic acini and acinar cells Ins, Glu and Som individually evoked small increases in amylase output compared with a much larger response with CCK-8. When the islet hormones were combined with CCK-8 there was no potentiation of amylase output. Similarly, when rats were rendered diabetic by prior treatment with streptozotocin Ins, Glu and Som failed to potentiate the secretory response of CCK-8. In fura-2-loaded pancreatic acinar cells Ins or Glu evoked small increases in [Ca2+]i compared with a much larger elevation with CCK-8. Ins, Glu and Som each enhanced the CCK-8-evoked [Ca2+]i. Genistein elicited a decrease in [Ca2+]i both in the absence and presence of the islet hormones. It also decreased the elevation in [Ca2+]i resulting from the combined presence of CCK-8 with either Ins or Glu but it had no effect on CCK-8 in combination with Som. In pancreatic acinar cells from diabetic rat Ins, Glu and Som had no detectable effect on CCK-8-evoked elevation in [Ca2+]i compared with the response obtained with CCK-8 alone. CCK-8-immunopositive cells were distributed around the walls of blood vessels, numerous Ins-positive cells in the central and peripheral parts of the islets of Langerhans, Glu-immunoreactive cells in the periphery of islets and Som-positive cells in the outer part of the islets. During diabetes, the number of CCK-immunopositive cells remained unchanged whereas the number of Ins-positive cells decreased coupled with an increase in the number of Glu-positive cells. The results indicate that both tyrosine kinase and cellular Ca2+ seem to be the intracellular mediators involved with the enhanced secretory responses obtained with a combination of the islet hormones with CCK-8. Moreover, the presence of viable pancreatic islets of Langerhans seems to be associated with the potentiation of the islet hormones with CCK-8.