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Biomedical subjects

J E Cox

Publications and source records attributed to J E Cox.

At least 19 recordsLinked to original sources
PubMed2001

Jejunal or portal vein infusions of lipids increase hepatic vagal afferent activity.

Jejunal infusions of linoleic acid, corn oil, or caprylic acid significantly increased hepatic vagal afferent activity, whereas saline infusions were ineffective. The magnitude of response was greatest with either linoleic acid or corn oil. Hepatic portal infusions of linoleic acid, Liposyn II, or caprylic acid significantly increased hepatic vagal afferent activity, whereas 5% albumin/phosphate buffer vehicle was ineffective. The magnitude of response was greatest with either linoleic acid or Liposyn II. These data show that either jejunal or portal infusions of lipids increase activity of hepatic vagal afferents and could potentially serve as a complementary and/or alternative substrate to celiac vagal afferents in mediating the effects of jejunal infusions of lipids in suppressing food intake.

Action Potentials↗
PubMed2001

Celiac vagotomy reduces suppression of feeding by jejunal fatty acid infusions.

We investigated the role of the celiac branch of the vagus nerve in suppression of food intake produced by jejunal fatty acids infusions. Following selective celiac vagotomy or sham surgery, adult, male Sprague-Dawley rats received 7 h infusions of linoleic acid or saline through indwelling jejunal catheters on four consecutive days. Although linoleic acid still produced significant suppression of intake in rats with celiac vagotomy, it was less effective in these animals than in controls. The temporal pattern of results suggested that celiac afferent fibers are involved in mediating both pre- and postabsorptive effects of infused fatty acids.

Afferent Pathways↗
PubMed2001

Changes in plasma gonadotrophin and prolactin concentrations following castration of the pony stallion.

Concentrations of gonadotrophins and prolactin were recorded in pony stallions castrated during the early breeding season, to examine the regulatory role of the gonad at a time when testosterone has been postulated to exert positive feedback on LH secretion. Further, gonadotrophin concentrations in geldings are reported to return to values within the normal range of the entire stallion. In an attempt to characterize this species-specific reversal, the gonadotrophin concentrations of 6 male ponies castrated on 25 March were monitored for 4 months, and 4 stallions were used to generate control data. Blood samples were collected daily, from 3 d before to 10 d after castration (Day 0), and weekly thereafter until Day 122. The pituitary response to castration was immediate. Castration resulted in a previously unreported, dramatic (13-fold) but transient (3 d) surge in circulating concentrations of LH. Concentrations of LH and FSH increased in a logarithmically scaled (LH, R2 = 0.77; FSH, R2 = 0.93) manner over the subsequent 5 wk, during which temporal changes in concentrations of both hormones were strongly correlated (R2 = 0.97). The ratio of plasma gonadotrophin concentrations was consistent throughout (LH:FSH, 1.43 +/- 0.04). Maximal concentrations of LH (20.58 +/- 1.97 ng/mL, Day 34.8 +/- 3.2) were attained approximately 2 wk before the peak in FSH (16.99 +/- 1.97 ng/mL, Day 49.7 +/- 3.0). Plasma gonadotrophin concentrations exceeded those of entire stallions throughout the study. The equine testes inhibited LH secretion during the early breeding season, and no chronic decrease in plasma gonadotrophin concentrations was recorded. However, the LH surge evident for 3 d immediately afer castration, may be related to the dynamic seasonal interaction between gonadal steroids and the regulation of pituitary gonadotrophin release.

Animals↗
PubMed2000

The meaning of home: how it shapes the practice of home and hospice care.

Nurses often hear clients and their families express a strong desire to "go home" from the hospital or nursing home. The purpose of this article is to explore what they mean when they make this request and how this meaning of home can shape the practice of home and hospice care. To do this, definitions of home and a health-at-home model are described and applied through a case study.

Aged↗
PubMed2000

Responses of celiac and cervical vagal afferents to infusions of lipids in the jejunum or ileum of the rat.

Multiunit celiac and single-unit cervical recordings of vagal afferents were performed before and during infusions of fatty acids, triglycerides, or saline into either the ileum or jejunum of the rat. In multiunit recordings, lipids increased activity of vagal afferents to a greater extent than saline. The greatest increases in vagal afferent activity resulted from infusions of linoleic acid, conjugated linoleic acid, or oleic acid. The triglycerides, corn oil or Intralipid, were less effective than the fatty acids in affecting vagal afferent activity. Ileal pretreatment with the hydrophobic surfactant Pluronic L-81 significantly attenuated the response of celiac vagal afferents to ileal infusion of linoleic acid. Single-unit recordings of cervical vagal afferents supported the multiunit data in showing lipid-induced increased vagal afferent activity in approximately 50% of ileal units sampled and 100% of a limited number of jejunal units sampled. These data demonstrate that free fatty acids can activate ileal and jejunal vagal afferents in the rat, and this effect can be attenuated by pretreatment with a chylomicron inhibitor. These data are consistent with the view that lipid-induced activation of vagal afferents could be a potential substrate for the inhibitory effects of intestinal lipids on gastrointestinal function, food intake, and body weight gain.

Animals↗
PubMed2000

Suppression of food intake, body weight, and body fat by jejunal fatty acid infusions.

Three experiments investigated effects of jejunal lipid infusions given on 4 or 21 consecutive days in adult, male Sprague-Dawley rats. In experiment 1, 7-h infusions of linoleic or oleic acid (0.2 ml/h for 7 h; total load = 11.5 kcal) on 4 consecutive days reduced total intake (ad libitum consumption of the liquid diet Boost, Mead Johnson, plus load) by approximately 15% and decreased weight gain compared with 4-day tests with saline administration. In experiment 2, linoleic acid at 0.1 ml/h for 7 h (5.7 kcal) was ineffective, whereas the same load delivered in 3.5 h produced effects similar in magnitude to those in the first experiment. In experiment 3, jejunal infusions of linoleic acid (0.2 ml/h for 7 h) on 21 consecutive days reduced mean total intake by 16%, body weight by 10%, and carcass fat by 48% compared with controls receiving saline. The net decrease in caloric intake may reflect the combined activation of pre- and postabsorptive mechanisms, and it suggests a possible treatment for obesity.

Adipose Tissue↗
PubMed2000

The utility of screening chest radiographs for flight physicals.

Previous studies have shown low efficacy of screening chest radiographs in various populations. Findings of approximately 3,500 screening chest radiographs performed for flight duty were reviewed to determine the rate of detection of significant abnormalities. There were abnormal findings in 107 chest radiographs (3%). Fifty-five of these (1.6% of total), after additional evaluation, were found to be false positive. Only two medically significant conditions were found in the screening population. Based on our data, routine screening of flight duty applicants does not appear to be justified.

Adolescent↗
PubMed1999

Transthoracic needle aspiration biopsy: variables that affect risk of pneumothorax.

PURPOSE: To analyze the influence of multiple variables on the rate of pneumothorax and chest tube placement associated with transthoracic needle aspiration biopsy of the lung. MATERIALS AND METHODS: In 346 patients, 331 computed tomographically (CT) guided and 24 fluoroscopically guided lung biopsies were performed. Variables analyzed were lesion size, depth, and location; number of pleural passes; needle size; presence of emphysema; and training level of the person who performed the biopsy. RESULTS: Pneumothorax occurred at 144 (40.4%) of 356 biopsies, including 139 (42.0%) CT-guided and five (21%) fluoroscopically guided biopsies. Chest tube placement was needed in 25 (17.4%) of 144 cases of pneumothorax (7% of all biopsies). An increased rate of pneumothorax was correlated with smaller lesion size (P = .001) and presence of emphysema (P = .01). Patients with emphysema were three times as likely to require chest tube placement. The pneumothorax rate was 15% (16 of 105) if no aerated lung was traversed and approximately 50% if aerated lung was penetrated. Lesion location, needle size, number of pleural passes, and level of training were not correlated with pneumothorax rate. CONCLUSION: Smaller lesion size and emphysema are strongly correlated with occurrence of pneumothorax. Pneumothorax was more than three times less frequent if no aerated lung was traversed. After pneumothorax, chest tube placements were related to the presence of emphysema.

Adolescent↗
PubMed1999

Pulmonary intravascular lymphomatosis: presentation with dyspnea and air trapping.

Intravascular lymphomatosis (IVL) is a rare lymphoid neoplasm that is typically of B-cell lineage and characterized by proliferation of malignant cells within small arterioles, capillaries, and venules. We report a patient with pulmonary IVL who presented clinically with progressive dyspnea, fever, and a dry cough. Pulmonary function tests revealed a marked decrease in diffusion capacity with airflow obstruction and severe air trapping. High-resolution CT (HRCT) of the chest with inspiratory and expiratory images revealed mosaic attenuation consistent with air trapping. Transbronchial biopsies revealed the diagnosis of IVL with capillary expansion in the alveolar and peribronchiolar interstitial tissue. IVL should be considered in the differential diagnosis of a patient with an interstitial lung disease, air trapping on pulmonary function tests, and mosaic attenuation on HRCT. Transbronchial biopsies may be the initial diagnostic procedure of choice.

Dyspnea↗
PubMed1998

Cholecystokinin satiety involves CCKA receptors perfused by the superior pancreaticoduodenal artery.

Three experiments compared the potency of the type A cholecystokinin (CCKA)-receptor antagonist devazepide for increasing intake of 30% sucrose when injected into the superior pancreaticoduodenal (SPD) artery (SPD group) or jugular vein (IV group). In experiment 1, 15 min of sucrose intake in adult, male Sprague-Dawley rats after 6 h of food deprivation was increased by devazepide (20 micrograms/kg) administered into the SPD artery whether given alone or in conjunction with cholecystokinin octapeptide (CCK-8, 2 micrograms/kg ip). Devazepide had no effect in the IV group. In experiment 2, injection of 8, 20, and 50 micrograms/kg of devazepide into the SPD artery increased sucrose intake of nondeprived rats. Only the highest dose was effective in the IV group. On subsequent tests, administration of 1 microgram/kg of CCK-8 significantly suppressed intake only in the SPD group. In experiment 3, nondeprived rats with SPD artery and jugular vein catheters were tested in a within-subjects design. Devazepide (20 micrograms/kg) increased sucrose intake after injection into the SPD artery, but not into the jugular vein. In experiment 4, intraduodenal devazepide (8, 20, and 50 micrograms/kg) had no effect. These results indicate that CCKA receptors within the SPD arterial bed mediate the satiating action of CCK, consistent with local action of duodenal CCK.

Animals↗
PubMed1997

CCK-8 activates hepatic vagal C-fiber afferents.

Intravenous administration of 2 micrograms/kg CCK-8 increased the single unit activity of 54% of hepatic vagal afferent fibers. Conduction velocity tests indicated that all of these units were C fibers. The increase in hepatic vagal activity produced by CCK-8 was significantly reduced by i.v. administration of 200 micrograms/kg of the CCKA receptor antagonist devazepide. Control comparisons indicated that this reduction was not an artifact of tachyphylaxis resulting from repeated administration of CCK-8. Further, the inability of pretreatment with atropine and hexamethonium to reduce the increases in hepatic vagal activity produced by CCK-8 suggests that the latter effect was not secondary to changes in gastrointestinal motor function. These outcomes demonstrate that activation of CCKA receptors by CCK-8 increases hepatic vagal afferent activity and support the view that the duodenal satiety action of CCK is mediated by the hepatic branch.

Animals↗
PubMed1997

Identification of tobacco-specific carcinogen in the cervical mucus of smokers and nonsmokers.

BACKGROUND: In 1996, an estimated 15,700 new cases of cancer of the uterine cervix and 4,900 deaths from this disease were expected to occur in the United States. In a recent international study, human papillomavirus DNA was found in more than 90% of cervical tumor specimens examined, irrespective of the nationality of the patients from whom the samples were obtained. Although infection with human papillomavirus is the major known risk factor for the development of cervical cancer, it alone is not sufficient. Other etiologic factors that have been associated with this disease include deficiencies in micronutrients, lower socioeconomic status, oral contraceptive use, and cigarette smoking. Several compounds from cigarette smoke (nicotine and its major metabolite, cotinine) have been identified in cervical mucus, and the occurrence of smoking-related DNA damage in the cervical epithelium has been documented. PURPOSE: This investigation was conducted to determine for the first time whether carcinogenic tobacco-specific N-nitrosamines are present in the cervical mucus of cigarette smokers and of nonsmokers (most likely as a result of environmental exposure). METHODS: Cervical mucus specimens from 15 smokers and 10 nonsmokers were subjected to supercritical fluid extraction with the use of carbon dioxide that contained 10% methanol, and the resultant extracts were analyzed for tobacco-specific nitrosamines by use of a very sensitive method that involved gas chromatography and mass spectroscopy analyses. RESULTS: In a total of 16 samples obtained from 15 women who were current smokers (two samples from the same woman), we detected the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) at concentrations that ranged from 11.9 to 115.0 ng/g of mucus. Only one of a total of 10 cervical mucus specimens obtained from 10 women who claimed to be nonsmokers did not contain detectable NNK, and NNK concentrations ranged from 4.1 to 30.8 ng/g of mucus in the specimens from the remaining nine women. The concentrations of NNK in specimens from cigarette smokers were significantly higher than those from nonsmokers (mean +/- standard deviation: 46.9 +/- 32.5 ng/g of mucus versus 13.0 +/- 9.3 ng/g of mucus; two-tailed Student's t test, P = .004). CONCLUSION: The cervical mucus of cigarette smokers contains measurable amounts of the potent carcinogen NNK. This compound represents the first tobacco-specific carcinogen identified in this physiologic fluid of women who smoke cigarettes. The presence of NNK in the cervical mucus of nonsmokers is likely due to environmental exposure or to the fact that some of the subjects in this study may not have revealed that they occasionally smoked cigarettes. IMPLICATIONS: The presence of NNK in human cervical mucus further strengthens the association between cervical cancer and tobacco smoking.

Adult↗
PubMed1997

Sand aspiration with near-drowning. Radiographic and bronchoscopic findings.

Sand and foreign-body aspiration may accompany drowning and near-drowning, but few details regarding such patients are available in the literature. We report a 26-yr-old woman who suffered near-drowning after a motor-vehicle accident. Initial attempts at ventilation were compromised by increased peak airway pressures, which decreased following the removal of large amounts of sand from the patient's endotracheal tube. Chest radiographs and computed tomographic (CT) scans of the patient obtained upon her arrival in the emergency department demonstrated sand bronchograms within the lower lobes of both lungs, and sand within the maxillary sinuses and stomach. We present the radiographic, bronchoscopic, and microbiologic findings within hours after this patient's accident, with a review of the literature and provisional recommendations for the management of such patients.

Accidents, Traffic↗
PubMed1996

Effect of pyloric cuffs on cholecystokinin satiety.

Because inflation of a pyloric cuff during feeding blocks gastric emptying and increases gastric distention, this device was used to test the hypothesis of synergism between gastric distention and cholecystokinin octapeptide (CCK-8) in reducing intake. Adult, male Sprague-Dawley rat were allowed 20-min access to 30% sucrose, with or without inflation of pyloric cuffs, after intraperitoneal injection of saline or 1, 2, or 4 micrograms/kg CCK-8. Cuff inflation resulted in large increases in gastric volume at the end of feeding tests. However, this manipulation failed to enhance the effectiveness of any dose of CCK-8. In fact, data analyses revealed trends suggestive of decreased effectiveness of the two lowest doses under these conditions. The effect of 4 micrograms/kg CCK-8 was almost identical in tests with and without cuff inflation. These results are contrary to the prediction of greater potency of CCK-8 resulting from increased gastric distention.

Animals↗
PubMed1996

Effects of dietary 1,4-phenylenebis(methylene)selenocyanate on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced DNA adduct formation in lung and liver of A/J mice and F344 rats.

1,4-Phenylenebis(methylene)selenocyanate (p-XSC) was tested for its ability to inhibit DNA adduct formation induced by the tobacco-specific N-nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in the liver and lung of A/J mice and F344 rats. Dietary p-XSC, providing a dose of 5 p.p.m. selenium, significantly inhibited the formation of 7-methylguanine (7-mGua) induced by a single i.p. injection of 10 mumol of NNK(12.8% inhibition at 4 h and 19.9% at 96 h) and O6-methylguanine (O6-mGua) (16.5% at 4 h and 34.8% at 96 h) in the liver of A/J mice. Dietary supplements of p-XSC providing 15 p.p.m. of selenium reduced the levels of 7-mGua by 17.3% (4 h) and 33.6% (96 h). The formation of O6-mGua was inhibited by 69.5% (4th) and 73.8 (96h). In A/J mouse lung DNA the most significant reduction was observed in levels of O6-mGua. Dietary p-XSC at 5 p.p.m. as selenium inhibited the formation of this adduct by 73.1% (4 h). Ninety-six hours after NNK injection, and at both time points with p-XSC providing 15 p.p.m. selenium, O6-mGua was not detected. Although levels of 7- mGua in mouse lung DNA were also reduced, this was significant only 4 h after carcinogen administration. In general, selenite at a5 p.p.m. as selenium had no significant effect on the levels of these lesions; however, it inhibited O6-mGua in the liver only 4 h after NNK administration. These effects may explain why there is chemopreventive activity for p-XSC, but not for selenite, in NNK-induced lung carcinogenesis in A/J mice. Moreover, these findings raised our interest in determining the potential chemopreventive activity of p-XSC against NNK-induced lung adenocarcinomas in male F344 rats by first determining its effects on NNK-induced DNA methylation in the lungs of rats. Diet supplemented with 10 p.p.m. selenium as p-XSC did indeed inhibit the formation of adducts in pulmonary DNA of F344 rats treated with four consecutive injections of 81 mg/kg of NNK. Statistically significant inhibition of O6-mGua formation was observed 4 h after carcinogen treatment in both pulmonary (49.1% inhibition) and hepatic (39.8%) DNA. Statistically significant inhibition of 7-mGua formation was also measured in lung DNA isolated 24 h after the last NNK injection (45.0%) and in liver DNA 4 h after carcinogen treatment (31.8%). These results suggest that p-XSC would also inhibit induction of lung adenocarcinoma in male F344 rats by NNK.

Adenocarcinoma↗
PubMed1996

Inhibition of sucrose intake by continuous celiac, superior mesenteric, and intravenous CCK-8 infusions.

Two experiments compared the potency of continuous infusions of cholecystokinin octapeptide (CCK-8) for reducing sucrose intake when administered into abdominal arteries or the jugular vein. Adult, male Sprague-Dawley rats received 22-min infusions of saline or several doses of CCK-8. Sucrose was available for 20 min, beginning 2 min after onset of infusions. In the first experiment, intraceliac CCK-8 in doses of 50, 125, and 312 ng produced significant reductions in intake, but no dose affected intake when administered into the jugular vein. In experiment 2, only the highest dose, 312 ng, suppressed intake when infused into the superior mesenteric artery, and jugular infusions were again ineffective. Behavioral observations indicated that intra-arterial CCK-8 had no affect on feeding within the first several minutes of test meals but accelerated the subsequent decline in incidence of feeding. These results suggest that receptors involved in cholecystokinin satiety are widely distributed within the gastrointestinal tract.

Animals↗
PubMed1995

Fathers of children born to adolescent mothers. Predictors of contact with their children at 2 years.

OBJECTIVE: To examine factors associated with long-term involvement of the fathers of children born to adolescent mothers receiving health care in a teen-tot clinic. DESIGN: Ninety-three first-time adolescent mothers younger than 18 years receiving care in a hospital-based teen-tot clinic participated in standardized structured interviews at 2 weeks and 24 months post partum. Data were obtained on demographic factors, the father's prenatal and delivery involvement, frequency of the father's contact with his child, and his participation in child care and financial support of the child. RESULTS: Factors associated with at least monthly contact between father and child during the first 24 months of the child's life were attending at least one prenatal visit, seeing the newborn in the hospital, and a reported supportive relationship between the young mother's family and the father at the 2-week interview. Age of the father and his education, work, or living arrangement did not predict involvement at 24 months. CONCLUSIONS: Our study suggests an association between a father's active participation in both the prenatal and neonatal periods and later contacts between children of adolescent mothers and their fathers. Since other studies indicate that paternal involvement results in more effective maternal parenting and satisfaction, interventions that encourage fathers' participation in both prenatal and intrapartum care should be developed and rigorously evaluated.

Adolescent↗