bluuebunny/crossref_metadata_2025 huggingface dataset:
Asthma, Viruses, and Nitric Oxide
Authors: SANDERS SCHERER P.
Published: November 2003

Over the last two decades there has been a worldwide increase in the morbidity and mortality associated with asthma, a chronic inflammatory disease of the airways. There is a growing body of evidence that suggests there is an association between upper respiratory viral infections, particularly rhinovirus infections, and asthma exacerbations. Virally induced airways hyperreactivity has been associated with elevated numbers of inflammatory cells in the bronchial mucosa. Upon virus infection, respiratory epithelial cells produce proinflammatory cytokines, including IL‐6, IL‐8, RANTES, and GM‐CSF, which could contribute to the increased inflammatory cell recruitment noted in the airways. Whether or not a viral infection triggers an asthma attack may depend upon many factors, including the types of inflammatory cells recruited to the airways, the viral load, and variations in the host antiviral response. There is evidence to support the idea that eosinophils from asthmatic and symptomatic atopic subjects may be primed to respond to chemotactic cytokines produced by infected epithelial cells. Rhinovirus infections may therefore enhance airway eosinophilia in asthmatics, leading to airway hyperresponsiveness and impaired pulmonary function. Nitric oxide is a potent inhibitor of both rhinovirus‐induced cytokine production and viral replication and may play an important role in the host response to viral infections. Based upon these observations, we speculate that nitric oxide donors may represent a novel therapeutic approach for the treatment of rhinovirus infections and viral exacerbations of asthma.
QT Interval and QT Dispersion Before and After Diet Therapy in Patients with Simple Obesity
Authors: MSHIU MERLYN E. , SAIKAWA TETSUNORI , ITO KENICHIRO , HARA MASAHIDE , SAKATA TOSHIIE
Published: November 2003

To evaluate whether a disordered QT interval and its dispersion in obese patients, if any, may be improved by therapeutic weight reduction, 36 obese patients admitted to our university hospital were examined over a 5‐year period from April 1, 1992 to March 31, 1997. Participants included 18 males and 18 females whose mean age ± SD was 28 ± 9 and 33 ± 14 years, respectively, and whose mean body mass index ± SD was 35 ± 5 and 38 ± 6 kg/m2, respectively. Thirty‐six control patients were matched in age and gender with the obese patients. All the obese patients were treated with behavioral therapy together with very‐low‐calorie conventional Japanese diet (VLCD: 370 kcal/day). A standard 12‐lead electrocardiogram (ECG) revealed longer maximum (445 ± 32 msec, mean ± SD) and minimum (388 ± 29 msec) heart rate corrected QT intervals (QTc intervals) in the obese group than in the control group (P < 0.0001 for each). QTc dispersion, defined as the difference between maximum and minimum QTc intervals derived from 12‐lead ECG, was greater in the obese group (57 ± 19 msec) than in the control group (32 ± 13 msec) (P < 0.0001). Both the maximum and minimum QTc intervals in the obese patients were shortened, respectively, to 434 ± 28 msec and 377 ± 29 msec (P < 0.05 for each) with no significant change in either QTc dispersion, QRS voltage, or QRS duration following weight reduction. The coefficient value from the linear regression line between QT interval and RR interval in the obese group was less than in the control group. Together, the results show that obesity per se causes both a prolongation of QTc interval and an increase in QTc dispersion, and that weight reduction improves the prolonged QTc interval observed in obese patients.
Median Eminence Lesions Reveal Separate Hypothalamic Control of Pulsatile Follicle‐Stimulating Hormone and Luteinizing Hormone Release
Authors: MARUBAYASHI UMEKO , YU WEN H. , MCCANN SAMUEL M.
Published: November 2003

The effects of hypothalamic lesions designed to destroy either the anterior median eminence (ME) or the posterior and mid‐ME on pulsatile release of follicle‐stimulating hormone (FSH) and luteinizing hormone (LH) were determined in castrated male rats. In sham‐operated animals, mean plasma FSH concentrations rose to peak at 10 min after the onset of sampling, whereas LH declined to a nadir during this time. In the final sample at 120 min, the mean FSH concentrations peaked as LH decreased to its minimal value. In rats with anterior ME lesions, there was suppression of LH pulses with continuing FSH pulses in 12 of 21 rats. On the other hand, in animals with posterior to mid‐ME lesions, 3 out of 21 rats had elimination of FSH pulses, whereas LH pulses were maintained. Fifteen of 42 operated rats had complete ME lesions, and pulses of both hormones were abolished. The remaining 12 rats had partial ME lesions that produced a partial block of the release of both hormones. The results support the concept of separate hypothalamic control of FSH and LH release with the axons of the putative FSH‐releasing factor (FSHRF) neuronal system terminating primarily in the mid‐ to caudal ME, whereas those of the LHRH neuronal system terminate in the anterior and mid‐median eminence. We hypothesize that pulses of FSH alone are mediated by release of the FSHRF into the hypophyseal portal vessels, whereas those of LH alone are mediated by LHRH. Pulses of both gonadotropins simultaneously may be mediated by pulses of both releasing hormones simultaneously. Alternatively, relatively large pulses of LHRH alone may account for simultaneous pulses of both gonadotropins since LHRH has intrinsic FSH‐releasing activity.
A Genetic Developmental Model of Iron Deficiency: Biological Aspects
Authors: MORSE ANDREW C. , BEARD JOHN L. , JONES BYRON C.
Published: November 2003

Numerous studies have demonstrated the negative impact of iron deficiency on growth and development. The present study expands on the published literature by exploring the role of genetics and developmental timing on the impact of iron deficiency on development in two strains of mice. Growth rates, organ weights, and hematological responses to an iron‐deficient diet differed by strain and sex. The results from this study provided novel insight into iron metabolism and the impact of iron deficiency in C57 and DBA strains of mice. Future studies should continue to examine the contributions of both genetics and sex to the development of iron deficiency.
Genotype and Diet Effects in Lean and Obese Zucker Rats Fed Either Safflower or Coconut Oil Diets
Authors: CLEARY MARGOT P. , PHILLIPS FREDERICK C. , MORTON RUTH A.
Published: November 2003

Previously we reported that suckling lean heterozygous (FA/fa) Zucker rats had a number of adipose tissue measurements intermediate between those of homozygous lean (FA/FA) and obese (fa/fa) rats. However, in young adult male rats maintained on a low‐fat diet, these differences were no longer apparent (i.e., values for the two lean genotypes were similar). In the present study we determined whether the heterozygous effect of the “fa” gene was dependent on the consumption of a high‐fat diet. Mother rats were fed high‐fat diets containing either safflower (SOD) or coconut (COD) oil throughout mating and lactation. Homozygous lean male and female rats were bred, as well as obese male and lean heterozygous female rats. Suckling rats were studied at 17 days of age. Additional male rats were maintained on the same diet as their mothers until 11–12 weeks of age. Obese suckling rats had higher body weights than lean pups. Inguinal fat pad weights and pad‐to‐body weight ratios followed the pattern of obese greater than lean (FA/fa) pups that were greater than lean (FA/FA) pups. A similar relationship was found for adipose tissue lipogenic enzyme activities. At 11–12 weeks of age, measurements followed the general pattern of obese rats having greater values than lean rats (i.e., FA/fa = FA/FA). SOD‐fa/fa rats had higher hepatic lipogenic enzyme activities than COD‐fa/fa rats. In addition, SOD rats had higher fat cell numbers than COD rats. These results suggest that specific fatty acids can alter adipocyte proliferation and/or differentiation in vivo. In addition, there appears to be a defect of fatty acid regulation in livers of genetically obese rats. The heterozygous effect of the “fa” gene in suckling Zucker rats was confirmed. However, high‐fat feeding did not result in a heterozygous effect in young adult lean male rats. We will next evaluate the role of sex on this effect.
Effect of Pregnancy‐Specific β1‐Glycoprotein on the Development of Preimplantation Embryo
Authors: WU SHAO‐MING , ARNOLD LORI L. , RONE JANICE , TRIVADI MANISHA , CHAN WAI‐YEE
Published: November 2003

The objective of this study is to test the hypothesis that members of the pregnancy‐specific β1‐glycoprotein (PSG) family enhance the growth and maturation of embryos. cDNA encoding two members of the PSG family, namely PSG1 and PSG3, were expressed in Chinese Hamster Ovary (CHO) cells with the expression vector pHβAPr‐1‐neo. Two‐cell stage mouse embryos were co‐cultured in a two‐chamber system with CHO cells expressing either recombinant PSG1 (rPSG1) or PSG3 (rPSG3) in the presence and absence of neutralizing PSG antibodies. The cleavage and maturation stage of the embryos was assessed at 12‐hr intervals. Mouse embryos co‐cultured with transfectants expressing rPSG1 showed a significant enhancement of cleavage and maturation rate compared to controls with P < 0.005–0.004. In co‐cultures with CHO cells expressing rPSG3, no significant difference from the controls was observed in the early stage of development until late blastocyst formation. At that stage, there was a statistically significant enhancement of development by rPSG3 when compared to controls with P < 0.001. These results suggest that PSG1 and PSG3 exhibit embryotropic activity at different stages of development in the mouse model.
Antianalgesic Action of Dynorphin A Mediated by Spinal Cholecystokinin
Authors: RADY JODIE J. , HOLMES BLYTHE B. , FUJIMOTO JAMES M.
Published: November 2003

Previous work indicates that the antianalgesic action of pentobarbital and neurotensin administered intracerebroventricularly in mice arises from activation of a descending system to release cholecystokinin (CCK) in the spinal cord where CCK is known to antagonize morphine analgesia. Spinal dynorphin, like CCK, has an antianalgesic action against intrathecally administered morphine. This dynorphin action is indirect; even though it is initiated in the spinal cord, it requires the involvement of an ascending pathway to the brain and a descending pathway to the spinal cord where an antianalgesic mediator works. The aim of the present investigation was to determine if the antianalgesic action of intrathecal dynorphin A involved spinal CCK. All drugs were administered intrathecally to mice in the tail flick test. Morphine analgesia was inhibited by dynorphin as shown by a rightward shift of the morphine dose‐response curve. The effect of dynorphin was eliminated by administration of the CCK receptor antagonists lorglumide and PD135 158. One hour pretreatment with CCK antiserum also eliminated the action of dynorphin. On the other hand, the antianalgesic action of CCK was not affected by dynorphin antiserum. Thus, CCK did not release dynorphin. Both CCK and dynorphin were antianalgesic against DSLET but not DPDPE, δ2 and δ1 opioid receptor peptide agonists, respectively. The results suggest that the antianalgesic action of dynorphin occurred through an indirect mechanism ultimately dependent on the action of spinal CCK.
Effects of Ethacrynic Acid on Intraocular Pressure of Anesthetized Rats
Authors: SEARLES ROBIN V. , JOHNSON MARTINIQUE , SHIKHER VLADIMIR , BALABAN CAREY D. , SEVERS WALTER B.
Published: November 2003

Ethacrynic acid (ECA) lowers intraocular pressure (IOP) by an effect usually ascribed to increased drainage of aqueous humor by the trabecular meshwork. Here, we describe the effects of a continuous 2‐hr intracameral infusion of balanced salt solution (BSS), with or without 2 mM ECA (sodium salt), on IOP of pentobarbital anesthetized rats. The infusion was divided into a constant (0.05 μl/min) and a periodic (0.25 μl/min) component that cycled 4 min on then 4 min off. This permitted the calculation of dynamic changes in resistive (trabecular and uveoslceral drainage) and nonresistive (aqueous synthesis, episcleral venous pressure) components of IOP by fitting a second‐order transfer function to the responses. ECA markedly blunted the BSS‐induced rise in IOP (P < 0.01). The rise in resistive mechanisms (ocular impedance) was transiently blunted by ECA (P < 0.05) during the third and fourth 8‐min cycles, and nonresistive mechanisms were reduced by ECA from cycles 3–10 (P < 0.05). Then, at the end of the infusion, the control and ECA dynamic values were similar (P > 0.05), although IOP of ECA‐treated rats was still slightly reduced (P < 0.05). The most likely explanation is a summation of small changes in both resistive and nonresistive components of IOP dynamics. Systemic blood pressure was unchanged within either group. The well‐known effects of ECA on the trabecular meshwork, alone, are insufficient to explain the dynamic changes in IOP observed in this model.
Tea Drinking and Cancer Risk: Epidemiologic Evidence
Authors: Chow Wong‐Ho , Blot William J. , McLaughlin Joseph K.
Published: November 2003

Tea and tea compounds have been shown to inhibit carcinogenic processes in experimental animals, raising the possibility that tea drinking may lower cancer risk in humans. However, epidemiologic studies have produced inconsistent evidence on the relation between tea drinking and cancer risk. Ecological data show considerable international variation in tea consumption but relatively small differences in cancer rates. Results from case‐control and cohort studies also are inconclusive. Nevertheless, high consumption of tea has been linked to a reduced risk of digestive tract cancers in a number of epidemiologic studies. A lack of detailed information on duration and amount of tea drinking, a narrow range of tea intake in some study populations, inadequate control for confounding, and potential biases in recall and reporting of tea drinking patterns in case‐control studies may have contributed to the diverse findings. Further research is needed before definitive conclusions on tea's impact upon cancer risk in humans can be reached.
The Chemopreventive Effects of Tea on Human Oral Precancerous Mucosa Lesions
Authors: Li Ning , Sun Zheng , Han Chi , Chen Junshi
Published: November 2003

A double‐blind intervention trial was conducted in patients with oral mucosa leukoplakia using a mixed tea product developed by the authors. Fifty‐nine oral mucosa leukoplakia patients, diagnosed by established clinical and pathological criteria, were randomly divided into a treated group (3 g mixed tea oral administration and topical treatment) and a control group (placebo and glycerin treatment). After the 6‐month trial, the size of oral lesion was decreased in 37.9% of the 29 treated patients and increased in 3.4%; whereas the oral lesion was decreased in 10.0% of the 30 control patients and increased in 6.7%. At the same time, the incidence of micronucleated exfoliated oral mucosa cells in the treated group (5.4 per 1000 cells) was lower than that in the control group (11.3 per 1000 cells)(P < 0.01); whereas it was 1.4 per 1000 cells in 20 healthy subjects. The micronuclei and chromosome aberration rate in the peripheral blood lymphocytes showed the same results. In pathological examination, there were significant differences (P < 0.05) in the number and total volume of the silver‐stained Nucleolar Organizer Regions (AgNOR) and the proliferating index of Proliferation Cell Nuclear Antigen (PCNA) in oral mucosa cell nuclei between the treated group and the control group which indicates that cell proliferation was decreased in the treated patients. The overall results provide some direct evidence on the protective effects of tea on oral cancer.
Mechanistic Findings of Green Tea as Cancer Preventive for Humans
Authors: Fujiki Hirota , Suganuma Masami , Okabe Sachiko , Sueoka Eisaburo , Suga Kenji , Imai Kazue , Nakachi Kei , Kimura Shunsaku
Published: November 2003

Based on our initial work with green tea, in which repeated topical applications of (−)‐epigallocatechin gallate (EGCG), the main green tea polyphenol, inhibited tumor promotion in a two‐stage carcinogenesis experiment on mouse skin (Phytother Res 1, 44–47, 1987), numerous scientists have since provided so much additional evidence of the benefits of drinking green tea that it is now an acknowledged cancer preventive in Japan, and will possibly soon be recognized as such in other countries. Our work has so far produced several important results with EGCG and green tea: a wide range of target organs in animal experiments for cancer prevention, wide bioavailability of 3H‐EGCG in various organs of mice, delayed cancer onset of patients with a history of consuming over 10 cups of green tea per day, and absence of any severe adverse effects among volunteers who took 15 green tea tablets per day (2.25 g green tea extracts, 337.5 mg EGCG, and 135 mg caffeine) for 6 months. This paper introduces three new findings: 1) EGCG interacted with the phospholipid bilayer membrane resulting in confirmation of the sealing effect of EGCG; 2) EGCG inhibited TNF‐α gene expression in the cells and TNF‐α release from the cells; 3) high consumption of green tea was closely associated with decreased numbers of axillary lymph node metastases among premenopausal Stage I and II breast cancer patients, and with increased expression of progesterone and estrogen receptors among postmenopausal ones. These results provide new insights into our understanding of the mechanisms of action of tea polyphenols and green tea extract as a cancer preventive.
Inhibitory Effect of Green and Black Tea on Tumor Growth
Authors: Conney A. H. , Lu Y.‐P. , Lou Y.‐R. , Xie J.‐G. , Huang M.‐T.
Published: November 2003

The administration of green tea, black tea, or (−)‐epigallocatechin gallate inhibited the growth of established nonmalignant and malignant tumors in tumor‐bearing mice. In experiments with black tea, we found that its oral administration inhibited DNA synthesis and enhanced apoptosis in both nonmalignant and malignant tumors in tumor‐bearing mice.
Direct Ultrastructural Imaging of Macrophages Using a Novel X‐Ray Contact Microscopy
Authors: Kado Masataka , Richardson Martin , Rajyaguru Jayshree M. , Muszynski Michael J. , Friedman Herman , Yamamoto Yoshimasa
Published: November 2003

A compact, high‐resolution, laser‐plasma, x‐ray contact microscopy method using a table‐top Nd:glass laser system has been developed. This x‐ray microscopy system was applied for the observation of macrophage ultrastructures. These images were produced using proximity imaging in which a 5‐ns pulse of soft x‐rays with wavelengths near and inside the water windows (23Å–44Å) produced by the laser‐plasma were absorbed by the specimen and then registered on a photo resist. The x‐ray images imprinted on the photo resist were then developed and analyzed with an atomic force microscope (AFM). Mouse thioglycollate‐elicited peritoneal macrophages in suspension were examined by this new x‐ray microscope. The x‐ray images of the macrophages were compared with those observed by conventional transmission electron microscopy (TEM). The x‐ray images showed no obvious organelles, including the nucleus and endoplasmic reticulum, as can be seen with TEM, but high‐ and low‐contrast structures caused by mass distribution of carbon were observed. Thus, using the x‐ray microscopy we visualized the first x‐ray images of macrophage ultrastructures. The successful x‐ray imaging of macrophage ultrastructure indicates that proximity x‐ray microscopy may be of value in studying physiology linked to the dynamics of a cell.
Cancer Chemopreventive Mechanisms of Tea Against Heterocyclic Amine Mutagens from Cooked Meat
Authors: Dashwood Roderick H. , Xu Meirong , Hernaez Judith F. , Hasaniya Nahidh , Youn Kristi , Razzuk Aziz
Published: November 2003

Cooking meat and fish under normal conditions produces heterocyclic amine mutagens, several of which have been shown to induce colon tumors in experimental animals. In our search for natural dietary components that might protect against these mutagens, it was found that green tea and black tea inhibit the formation of heterocyclic amine‐induced colonic aberrant crypt foci (ACF) in the rat. Since ACF are considered to be putative preneoplastic lesions, we examined the inhibitory mechanisms of tea against the heterocyclic amines. In the initial studies using the Salmonella mutagenicity assay, green tea and black tea inhibited according to the concentration of tea leaves during brewing and the time of brewing; a 2–3‐min brew of 5% green tea (w/v) was sufficient for >90% antimutagenic activity. N‐hydroxylated heterocyclic amines, which are direct‐acting mutagens in Salmonella, were inhibited by complete tea beverage and by individual components of tea, such as epigallocatechin‐3‐gallate (EGCG). Inhibition did not involve enhanced mutagen degradation, and EGCG and other catechins complexed only weakly with the mutagens, suggesting electrophile scavenging as an alternative mechanism. Enzymes that contribute to the metabolic activation of heterocyclic amines, namely microsomal NADPH‐cytochrome P450 reductase and N,O‐acetyltransferase, were inhibited by tea in vitro. Studies in vivo established that tea also induces cytochromes P450 and Phase II enzymes in a manner consistent with the rapid metabolism and excretion of heterocyclic amines. Collectively, the results indicate that tea possesses anticarcinogenic activity in the colon, and this most likely involves multiple inhibitory mechanisms.
The Prevention of Lung Cancer Induced by a Tobacco‐Specific Carcinogen in Rodents by Green and Black Tea
Authors: Chung Fung‐Lung
Published: November 2003

A growing body of evidence from studies in laboratory animals indicates that green tea protects against cancer development at various organ sites. We have previously shown that green tea, administered as drinking water, inhibits lung tumor development in A/J mice treated with 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐l‐butanone (NNK), a potent nicotine‐derived lung carcinogen found in tobacco. The inhibitory effect of green tea has been attributed to its major polyphenolic compound, epigallocatechin gallate (EGCG), and, to a lesser extent, to caffeine. We have also demonstrated that while levels of O6‐methylguanine, a critical lesion in NNK lung tumorigenesis, were not affected in lung DNA. However, the levels of 8‐hydroxydeoxyguanosine (8‐OH‐dG), a marker of oxidative DNA damage, were significantly suppressed in mice treated with green tea or EGCG. These studies underscore the importance of the antioxidant activity of green tea and EGCG for their inhibitory activity against lung tumorigenesis. Unlike green tea, the effect of black tea on carcinogenesis has been scarcely studied, even though the worldwide production and consumption of black tea far exceeds that of green tea. The oxidation products found in black tea, thearubigins and theaflavins, also possess antioxidant activity, suggesting that black tea may also inhibit NNK‐induced lung tumorigenesis. Indeed, bioassays in A/J mice have shown that black tea given as drinking water retarded the development of lung cancer caused by NNK. However, data on the relationship of black tea consumption with the lung cancer risk in humans are limited and inconclusive. There is a need for additional tumor bioassays in animal models to better examine the protective role of black tea against lung cancer. The development of adenocarcinomas and adenosquamous carcinomas in F344 rats upon chronic administration of NNK provides an important and relevant model for lung carcinogenesis in smokers. Thus far, no information was previously available regarding the effects of tea on this model. We conducted a 2‐year lifetime bioassay in F344 rats to determine whether black tea and caffeine are protective against lung tumorigenesis induced by NNK. Our studies in both mice and rats have generated important new data that support green and black tea and caffeine as potential preventive agents against lung cancer, suggesting that a closer examination of the roles of tea and caffeine on lung cancer in smokers may be warranted.
Analysis of Tea Polyphenols
Authors: Beecher Gary R. , Warden Beverly A. , Merken Howard
Published: November 2003

Tea is the most highly consumed beverage in the world, other than water. However, unlike water, tea contains substantial amounts of polyphenols that have unique biological activities and may be responsible for many of the health benefits of tea. As a result, it is essential to be able to measure the various tea‐associated polyphenols. Total polyphenol content is currently measured by using methodology based on reducing activity. Several HPLC systems with detectors that, collectively, have wide ranges in sensitivity have been developed for analysis of individual flavonoids in tea and biological samples, and for theaflavins in tea. Catechins also have been measured in plasma by solid phase extraction, addition of a chromophore, and colorimetric quantification. Except for theaflavins in tea, routine and robust methods for the measurement of polyphenol condensation products (dimers and thearubigens) in tea and biological samples have not been developed. Although in vitro and animal studies suggest substantial metabolism of flavonoids in the gastrointestinal tract, only a single HPLC procedure has been assembled for monitoring the metabolic products of quercetin in urine of human subjects.
Preemptive Pharmacologic Intervention in Radiation‐Induced Salivary Dysfunction
Authors: Taylor Samuel E. , Miller Edward G.
Published: November 2003

Xerostomia (“dry mouth”) is a symptom of several diseases. It also occurs as a side effect of certain therapeutic interventions, most frequently pharmacotherapy. The most severe and irreversible forms of salivary dysfunction result from damage to or loss of salivary acinar cells. One of the severest forms of iatrogenic salivary gland destruction results from the therapeutic doses of irradiation given to treat head and neck cancer or to purge the bone marrow before transplantation. Xerostomia encompasses a wide range of involvement, from an inconvenience when mild, to a debilitating condition when severe. Reports of the symptom of dry mouth by patients do not always correlate with the degree of diminished salivary flow. However, a significant loss of stimulated flow makes it difficult to process solid food into a bolus that can be swallowed. If sustained, nutritional deficiencies may result. Saliva also facilitates formation of speech patterns. Its loss hinders speaking and communicating, possibly causing the patient to withdraw from social interaction. Together these conditions can impair the physiological and psychological well‐being of the patient. Thousands of individuals undergo radiation therapy for head and neck cancer in the United States each year. Increasing numbers are receiving total body radiation before transplantation of bone marrow. Although the salivary gland is not one of the more actively dividing organs in the body, nevertheless it ranks as one of the most radiosensitive. The mechanism of this sensitivity is not understood. This article reviews human and animal pathophysiology of radiation‐induced salivary damage. We also discuss animal studies that have employed various strategies to modify and clarify this process. Finally, we describe encouraging results from early clinical trials suggesting that protection of salivary glands during therapeutic irradiation may be possible.
Anti‐Apoptotic Actions of Cytokines in Mammalian Cells
Authors: Desai Bhaloo J. , Gruber Helen E.
Published: November 2003

Apoptosis is now widely recognized as an important mode of cell death.Since the apoptotic pathway is an active process, modulation of apoptosis isimportant in our understanding of cell pathophysiology. Recent data have shown theinhibition of apoptosis in different cell types exposed to certain cytokines. Therapeuticsthat modulate the regulation of apoptosis provide an opportunity for the treatment ofcertain diseases. There are many reviews for apoptosis induction and the regulatorsinvolved. The present report selects important articles on the recent data showing theanti‐apoptotic ability of cytokines in mammalian cells. Other novel compoundsshowing anti‐apoptotic functions are also reviewed.
The Hepatic Uptake of Rat High‐Density Lipoprotein Cholesteryl Ester is Delayed After Treatment with Cholesteryl Ester Transfer Protein
Authors: Botham Kathleen M. , Avella Michael , Cantafora Alfredo , Bravo Elena
Published: November 2003

The effects of cholesteryl ester transfer protein (CETP) on the direct uptake of HDL cholesteryl ester by the liver was investigated using the rat in vivo and the isolated perfused rat liver as experimental models. Rat plasma was incubated with [3H]cholesterol in the presence or absence of partially purified human CETP for 18 hr and [3H] cholesteryl ester‐labeled HDL was then isolated by ultracentrifugation. The CETP‐treated as compared to untreated HDL showed a small shift toward a lower density in the peak of lipoprotein cholesterol, suggesting that the HDL particle size was increased. After injection of the labeled HDL into rats in vivo, more radioactivity remained in the plasma after 60 min when the CETP‐treated preparation was used, but the amounts found in the liver and secreted in the bile were not significantly different from those obtained with the untreated HDL. The distribution of the label remaining in the plasma after 60 min between different density fractions corresponding to HDL subclasses suggested that the uptake of HDL2 and HDL3 was delayed by CETP treatment. Radioactivity from CETP‐treated HDL was also removed from the perfusate of isolated perfused rat livers more slowly than that from untreated HDL, and in this case the amount found in the liver after 60 min was significantly lower. These findings indicate that treatment with CETP has a direct inhibitory effect on the clearance of rat HDL cholesteryl ester from the blood and its uptake by the liver.
Docosahexaenoic Acid is an Antihypertensive Nutrient That AffectsAldosterone Production in SHR
Authors: Engler Marguerite M. , Engler Mary B. , Goodfriend Theodore L. , Ball Dennis L. , Yu Zhigang , Su Ping , Kroetz Deanna L.
Published: November 2003

The effects of dietary docosahexaenoic acid (DHA), an ω‐3 polyunsaturated fatty acid, on blood pressure and some pressure‐regulating systems were measured in young spontaneously hypertensive rats (SHR). Plasma aldosterone and corticosterone levels, adrenal aldosterone production in vitro, and characteristics of adrenal angiotensin receptors were measured after 6 weeks of diet. Renal cytochrome P450 (CYP) 4A gene expression and arachidonic acid metabolism by renal microsomes were also investigated. Plasma cholesterol, triglycerides, and high‐density lipoprotein cholesterol were measured. Diets contained either corn/soybean oil alone (CSO), or oil enriched with DHA. After 6 weeks, rats fed DHA had systolic blood pressures averaging 34 mmHg less than controls (P < 0.001). Plasma aldosterone levels were 33% lower in the DHA‐fed animals than in controls (22 ± 3 vs. 33 ± 3.7 ng/dl, P < 0.05). Plasma levels of corticosterone were 18% lower in animals fed DHA than in controls, but this difference was not statistically significant. Adrenal glomerulosa cells from DHA‐fed rats produced less aldosterone in vitro in response to angiotensin II, ACTH, or potassium. The difference was less marked when aldosterone production was stimulated by supplying exogenous corticosterone, suggesting an effect of DHA on postreceptor steps in signal transduction or the early pathway of aldosteronogenesis. We found no significant differences in angiotensin receptor subtype, number, or affinity. Production of arachidonic epoxides by renal microsomes was 17% lower in DHA‐fed animals than in controls (P < 0.05). Renal cortical mRNA levels of CYP4A genes and formation of 19‐ and 20‐hydroxyeicosatetraenoic acid (HETE) did not differ between dietary groups. Plasma total cholesterol and high‐density‐lipoprotein (HDL) levels were significantly reduced in SHR fed the DHA supplement, but triglyceride levels were not significantly different. The effects of DHA on steroid and eicosanoid metabolism may be part of the mechanism by which this fatty acid prevents some of the hypertension in growing SHR.
The Influence of Hepatic Venous Oxygen Saturation on the Liver's Synthetic Response to Metabolic Stress
Authors: Dahn Michael S. , Lange M. Patricia , Benn Sally
Published: November 2003

Hepatic oxygen consumption (HVO2) and hepatic venous oxygen saturation (ShvO2) were assessed in the isolated perfused rat liver under conditions that mimic critical illness in an effort to assess their utility in predicting the functional status of the liver. Flow rates were adjusted over the physiologic range of oxygen transport as indicated by the hepatic venous O2 saturation range of 10%–75%. HVO2 was found to be transport (HDO2) dependent only when perfusate conditions contained an increased counterregulatory hormone (glucagon, epinephrine, dexamethasone) stimulus or a high lactate concentration. In the absence of a metabolic load, (substrate and hormone‐free perfusate), HVO2 was transport independent even at an ShvO2 as low as 10%. Although transport dependency of HVO2 is frequently used to infer tissue ischemia, hepatic oxygen consumption was poorly correlated with synthetic function under all conditions. In contrast, hepatic albumin production was directly related to ShvO2 at all levels of HDO2 and under all perfusion conditions indicating that this metabolic process is particularly sensitive to reductions in oxygen availability, which is more reliably predicted by venous saturation measurements. However, glucose and urea synthesis were almost independent of ShvO2. These findings indicate that various hepatic processes are affected differentially by stress conditions and flow alterations that may exist during critical illness, and protein synthesis is particularly sensitive to oxygen deprivation. Additionally, hepatic venous oxygen saturation measurement, but not HVO2, serves as a useful surrogate marker for hepatic albumin production suggesting that regional venous oximetry may play an important role in the detection of hepatic functional impairment.
Replication of Clinical Measles Virus Strains in Hispid Cotton Rats
Authors: Wyde Philip R. , Moore‐Poveda Donna K. , Daley Natalie J. , Oshitani Hitoshi
Published: November 2003

An alternative model to nonhuman primates to study measles virus (MV) pathogenesis, to evaluate potential MV vaccines, or to screen for potential antivirals effective against this virus is highly desirable. The laboratory‐adapted Edmonston strain of MV has been reported to replicate in the lungs of hispid cotton rats following intranasal inoculation, immunosuppress infected animals, and disseminate widely from the lungs, making these animals a candidate model. However, clinical MV strains have generally not been found to grow in these animals, limiting the utility and acceptance of this model. In the present studies we demonstrate reproducible replication of several clinical MV strains in hispid cotton rats. As with the Edmonston strain, leukocytes appear to be the primary target cells of these viruses following intranasal inoculation, and extrapulmonary dissemination is common. It is also demonstrated that prior MV infection or immunization of test animals with MV vaccine prevents pulmonary tract infection. These findings should make the MV‐cotton rat model more acceptable.
Human Pluripotent and Progenitor Cells Display Cell Surface Cluster Differentiation Markers CD10, CD13, CD56, andMHC Class‐I
Authors: Young Henry E. , Steele Timothy A. , Bray Robert A. , Detmer Kristina , Blake Lisa W. , Lucas Paul W. , Black Asa C.
Published: November 2003

Each year millions of people suffer tissue loss or end‐stage organ failure. While allogeneic therapies have saved and improved countless lives, they remain imperfect solutions. These therapies are limited by critical donor shortages, long‐term morbidity, and mortality. A wide variety of transplants, congenital malformations, elective surgeries, and genetic disorders have the potential for treatment with autologous stem cells as a source of HLA‐matched donor tissue. Our current research is aimed at characterizing cell surface cluster differentiation (CD) markers on human progenitor and pluripotent cells to aid in isolating comparatively purified populations of these cells. This study examined human pluripotent and progenitor cells isolated from fetal, mature, and geriatric individuals for the possible presence of 15 CD markers. The response to insulin and dexamethasone revealed that the cell isolates were composed of lineage‐committed progenitor cells and lineage‐uncommitted pluripotent cells. Flow cytometry showed cell populations positive for CD10, CD13, CD56, and MHC Class‐I markers and negative for CD3, CD5, CD7, CD11b, CD14, CD15, CD16, CD19, CD25, CD45, and CD65 markers. Northern analysis revealed that CD13 and CD56 were actively transcribed at time of cell harvest. We report the first identification of CD10, CD13, CD56, and MHC Class‐I cell surface antigens on these human cells.
Functional Absence of FADD in PLC/PRF/5 Hepatoma Cells: Possible Involvement in the Transformation to Hepatoma in HBV‐Infected Hepatocytes
Authors: Suzuki Atsushi , Araki Takashi , Miura Masayuki , Tsutomi Yumi
Published: November 2003

The death receptor Fas transduces apoptotic death signaling upon stimulation by Fas ligand and plays a key role in viral hepatitis. When hepatitis‐B virus (HBV) infects hepatocytes, the Fas ligand/Fas system responds as the triggering machinery of hepatitis. However, some HBV‐infected cells may circumvent Fas‐mediated apoptosis and transform to hepatoma cells, as do PLC/PRF/5 hepatoma cells. Therefore, in the present study, we used PLC/PRF/5 hepatoma cells to investigate this ability to avoid Fas‐mediated apoptosis. When the cells were treated with an agonistic Fas antibody, they showed resistance to Fas‐mediated apoptosis. In contrast, HepG2 cells of the same hepatoma line succumbed. Caspase 3 and 8, which are essential regulators for Fas‐mediated cell death, were expressed in both hepatoma cell lines, but only HepG2 cells showed activation of the caspases. A comparison study of expression of other death‐associated factors between PLC/PRF/5 and HepG2 cells revealed no apparent differences. However, Far‐Western blotting analysis using the Fas death domain (FDD) showed a significant difference. Molecular weight comparison and immunoblotting analysis revealed that PLC/PRF/5 cells lack the FDD‐associated protein FADD. In addition, FDD‐injected HepG2 cells showed a resistance to Fas‐mediated apoptosis, and PLC/PRF/5 cells acquired Fas‐sensitivity by FADD injection. Here, we propose that a functional absence of FADD is one of the pathways for the carcinogenesis of HBV‐infected hepatocytes.
Dietary Intrinsic Phytate Protects Colon from Lipid Peroxidation in Pigs with a Moderately High Dietary Iron Intake
Authors: Porres Jesús M. , Stahl Chad H. , Cheng Wen‐Hsing , Fu Yangxin , Roneker Karl R. , Pond Wilson G. , Lei Xin Gen
Published: November 2003

High iron consumption has been proposed to relate to an increase in the risk of colon cancer, whereas high levels of supplemental sodium phytate effectively reduce iron‐induced oxidative injury and reverse iron‐dependent augmentation of colorectal tumorigenesis. However, the protective role of intrinsic dietary phytate has not been determined. In this study, we examined the impact of removing phytate present in a corn‐soy diet by supplemental microbial phytase on susceptibility of pigs to the oxidative stress caused by a moderately high dietary iron intake. Thirty‐two weanling pigs were fed the corn‐soy diets containing two levels of iron (as ferrous sulfate, 80 or 750 mg/kg diet) and microbial phytase (as Natuphos, BASF, Mt. Olive, NJ, 0 or 1200 units/kg). Pigs fed the phytase‐supplemented diets did not receive any inorganic phosphorus to ensure adequate degradation of phytate. After 4 months of feeding, liver, colon, and colon mucosal scrapings were collected from four pigs in each of the four dietary groups. Colonic lipid peroxidation, measured as thiobarbituric acid reacting substances (TBARS), was increased by both the high iron (P< 0.0008) and phytase (P< 0.04) supplementation. Both TBARS and F2‐isoprostanes, an in vivo marker of lipid peroxidation, in colonic mucosa were affected by dietary levels of iron (P< 0.03). Mean hepatic TBARS in pigs fed the phytase‐supplemented, high iron diet was 43%–65% higher than that of other groups although the differences were nonsignificant. Moderately high dietary iron induced hepatic glutathione peroxidase activity (P= 0.06) and protein expression, but decreased catalase (P< 0.05) in the colonic mucosa. In conclusion, intrinsic phytate in corn and soy was protective against lipid peroxidation in the colon associated with a moderately high level of dietary iron.
Antioxidant Enzyme Activity in Human Abdominal Aortic Aneurysmal and Occlusive Disease
Authors: Dubick Michael A. , Keen Carl L. , DiSilvestro Robert A. , Eskelson Cleamond D. , Ireton Jennifer , Hunter Glenn C.
Published: November 2003

The present study further investigates evidence for lipid peroxidation in atherosclerotic aortic tissue by determining the activity of antioxidant enzymes and concentrations of lipid peroxide fluorochromes in abdominal aortas from 15 patients with abdominal aortic aneurysms (AAA), an additional 7 patients with ruptured abdominal aneurysms, and 12 patients with atherosclerotic occlusive disease (AOD). Aortas from nonatherosclerotic organ donors served as nondiseased controls. Cu, Zn‐superoxide dismutase (Cu,Zn‐SOD) activities in AAA and AOD tissues were 16% and 25% of control activity, respectively. Mn‐SOD activity in diseased aortae were about 65% of controls. CuZn‐SOD protein in AAA and AOD was 56% and 100% of controls, respectively, resulting in significantly lower CuZn‐SOD specific activity in these tissues. Ruptured AAA tissue also had low SOD activity and protein. Glutathione peroxidase (GPx) activity in AAA and AOD aortas was 70% and 65% of controls, respectively, and glutathione reductase (GR) activity in AAA and AOD aortas was 80% and 65% of control activities, respectively. These results were associated with significantly higher lipid peroxide fluorochromes, expressed as U/g aorta, in both groups of atherosclerotic aortas than in controls. AOD aortas had 33% higher fluorescence than AAA aortas, but the highest levels were seen in ruptured AAA. These data further support the involvement of free radicals and lipid peroxidation in atherosclerotic aortic disease, but do not indicate that these mechanisms are specifically involved in aneurysm formation versus development of occlusive disease.
Vitamin D and Prostate Cancer
Authors: Blutt Sarah E. , Weigel Nancy L.
Published: November 2003

Classically, the actions of vitamin D have been associated with bone and mineral metabolism. More recent studies have shown that vitamin D metabolites induce differentiation and/or inhibit cell proliferation of a number of malignant and nonmalignant cell types including prostate cancer cells. Epidemiological studies show correlations between the risk factors for prostate cancer and conditions that can result in decreased vitamin D levels. The active metabolite of vitamin D, 1,25‐dihydroxyvitamin D3 (calcitriol), inhibits growth of both primary cultures of human prostate cancer cells and cancer cell lines, but the mechanism by which the cells are growth‐inhibited has not been clearly defined. Initial studies suggest that calcitriol alters cell cycle progression and may also initiate apoptosis. One of the disadvantages of using vitamin D in vivo is side‐effects such as hypercalcemia at doses above physiological levels. Analogs of calcitriol have been developed that have comparable or more potent antiproliferative effects but are less calcemic. Further research into the mechanisms of vitamin D action in prostate and identification of suitable analogs for use in vivo may lead to its use in the treatment or prevention of prostate cancer.
Induction of EGFR Tyrosine Kinase in the Gastric Mucosa of Diabetic Rats
Authors: Khan Ahmed J. , Fligiel Suzanne E. G. , Liu Lei , Jaszewski Richard , Chandok Arun , Majumdar Adhip P. N.
Published: November 2003

Diabetes mellitus is associated with spontaneous gastric mucosal injury and enhanced susceptibility of the mucosa to damaging agents. Little information is available about the biochemical changes that occur in the gastric mucosa of diabetes mellitus. Evidence is accumulating that tyrosine kinases, particularly the EGF‐receptor (EGFR), are involved in regulating a variety of structural and functional properties of the gastric mucosa. The primary objectives of this investigation were to determine whether diabetes induces morphological changes in the gastric mucosa, and if so, whether these changes are associated with alterations in EGFR tyrosine kinase. Diabetes‐induced changes in gastric mucosal morphology were also examined. Diabetes was induced in 3‐ to 4‐month‐old male Fischer‐344 rats by streptozotocin (STZ; 45 mg/kg; i.v.). Four weeks after induction of diabetes mellitus, the gastric mucosa of overnight‐fasted rats was found to be slightly atrophic. A reduction in gastric mucosal thickness with deposition of fibrous tissue above the muscularis layer was observed in the stomach of overnight‐fasted diabetic rats. These changes were associated with a marked stimulation in tyrosine kinase activity and protein expression of EGFR. The relative concentrations of several precursor forms of TGF‐α in both membrane and cytosolic fractions from the gastric mucosa of overnight‐fasted diabetic rats were also found to be significantly above the corresponding controls. This suggests that endogenous TGF‐α may play a critical role in regulating mucosal EGFR tyrosine kinase through a juxtacrine/paracrine mechanism.
Glucocorticoid Metabolism in Proximal Tubules Modulates Angiotensin II‐Induced Electrolyte Transport
Authors: Brem Andrew S. , Bina Robert B. , Fitzpatrick Camille , King Thomas , Tang Shiow‐Shih , Ingelfinger Julie R.
Published: November 2003

The hormonal interactions that regulate electrolyte transport in the proximal tubule are complex and incompletely understood. Since endogenous glucocorticoids and angiotensin II each can affect electrolyte transport in this renal segment, we hypothesized that local metabolism of glucocorticoids by the enzyme 11β‐hydroxysteroid dehydrogenase (11β‐HSD) might alter the response to angiotensin II. Studies were conducted in cultured origin defective SV‐40 transformed immortalized renal proximal tubule cells (IRPTC) derived from weanling Wistar rat kidney. The 11β‐HSD contained in these cells uses NADP+, has an apparent Km for corticosterone of 1.6 μM, but functions only as a dehydrogenase (corticosterone → 11‐dehydro‐corticosterone). When mounted in modified Ussing chambers, IRPTC generate a transmembrane current, and angiotensin II (10 pM to 10 μM) increases this sodium‐dependent current. Cells incubated with corticosterone (100 nM) and the 11β‐HSD inhibitor carbenoxolone (CBX) (1 μM) for 24 hr and then acutely stimulated with angiotensin (10 nM) show a greater rise in current than do cells exposed to corticosterone alone and stimulated with angiotensin (corticosterone + CBX: 64.2%± 20.5% vs. corticosterone: 18.8%± 5.9%; P < 0.02 at 180 min)[mean ± SE percentage above baseline, n= 8/group]. Cells exposed to corticosterone (100 nM) or CBX (1 μM) alone for 24 hr and then stimulated with angiotensin II (10 nM) had responses similar to controls. Thus glucocorticoids can enhance angiotensin II‐induced electrolyte transport in proximal tubule epithelial cells when local 11β‐HSD is inhibited.