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Biomedical subjects

S E Ellis

Publications and source records attributed to S E Ellis.

14 recordsLinked to original sources
PubMed2006

Mammary response to exogenous prolactin or frequent milking during early lactation in dairy cows.

Frequent milking of dairy cows during early lactation results in a persistent increase in milk yield; however, the mechanism underlying this effect is unknown. We hypothesized that increased exposure of the mammary gland to prolactin (PRL) mediates the milk yield response. Fifteen multiparous Holstein cows were assigned to 3 treatments for the first 3 wk of lactation: twice daily milking with (2x + PRL) or without (2x) supplemental exogenous PRL, or 4 times daily milking (4x). Mammary biopsies were obtained at 7 DIM, and rates of [(3)H]thymidine incorporation into DNA in vitro were determined. Mammary expression of suppressors of cytokine signaling (SOCS)-1, -2, and -3; the long form of PRL-receptor; and alpha-lactalbumin mRNA was measured by real-time reverse-transcription PCR. Incorporation of [(3)H]thymidine into DNA was not affected by frequent milking or PRL treatment; however, analysis of autoradiograms revealed that stromal cell proliferation was greater in 4x cows. Mammary expression of SOCS-1 was not affected by milking frequency or PRL treatment. Expression of SOCS-2 mRNA was increased with frequent milking or PRL treatment, whereas expression of SOCS-3 mRNA was reduced by frequent milking or exogenous PRL. Abundance of PRL-receptor mRNA was reduced, whereas alpha-lactalbumin mRNA was increased with PRL treatment. These results demonstrate that the bovine mammary gland is responsive to exogenous PRL during early lactation. In addition, differences in the response to frequent milking or exogenous PRL during early lactation indicate distinct effects of PRL and milk removal on the mammary function of dairy cows.

Animals↗
PubMed2005

Ovarian and IGF-I axis control of mammary development in prepubertal heifers.

Although much is known about the endocrine control of bovine mammary development, most heifer work has focused on periods near the time of puberty or during gestation. However, we have found that ovariectomy in the prepubertal period also markedly impacts mammary development well before the onset of estrus would have normally occurred. Interactions between the pituitary and ovary to control udder development are mediated at least in part via alteration in concentrations of local IGF-I axis molecules within the developing mammary gland. For example, in heifers treated with growth hormone or estrogen, expression of IGF-I binding proteins (IGFBP-3) protein was reduced, thus effecting an increase in free IGF-I. Ovariectomized heifers had reduced rates of epithelial cell proliferation, fewer IGF-I receptors, and less local IGF-I. Mammary tissue expression of fibronectin was increased in ovariectomized heifers, but laminin expression was higher in controls. Thus, alterations in specific extracellular matrix proteins likely impact heifer mammary development. As a result, we have initiated calfhood studies. At 30 days of age, it is difficult to detect parenchymal tissue in the udder. Only a thin cord of parenchymal tissue (150 mg per gland) is discernible. By 75 days of age, a rounded, walnut-like mass of mammary parenchymal tissue becomes very evident and at 90 days of age, this mass of tissue has grown to approximately 10 g, a approximately 60-fold increase. At 2 months of age, most proliferating epithelial cells (>92%) are confined to a population of light and intermediate-staining parenchymal cells. Between 2 and 5 months of age, a dark-staining cell population markedly emerges, but these dark cells were rarely labeled with bromodeoxyuridine (BrdU) and are likely to represent a more differentiated or committed cell lineage. The coordinated change in the proportions of each cell type suggests a progression from light-, to intermediate-, to dark-staining cell phenotypes. We are currently focusing on the importance of the ovary and mammary tissue synthesis of estrogens on emergence of specific populations of putative mammary stem cells.

Aging↗
PubMed2005

Exposure to short day photoperiod during the dry period enhances mammary growth in dairy cows.

Exposure to short day photoperiod (SD; 8 h light:16 h dark) during the dry period increased milk yield of cows in the subsequent lactation. We hypothesized that this effect is due to increased growth of mammary cells in response to enhanced prolactin signaling to influence the insulin-like growth factor (IGF) axis. Multiparous Holstein cows were dried off 60 d before parturition and assigned to long day photoperiod (LD; 16 h light:8 h dark) or SD during the dry period. Mammary biopsies were obtained at approximately -40, -20, -10 and +10 d relative to expected calving. Expression of IGF-I, IGF-II, and IGF binding protein-5 mRNA was assessed by real time reverse transcription-polymerase chain reaction. In SD cows, incorporation of [3H]-thymidine in vitro increased from -40 d to -20 d and was greater at -20 d than in LD cows. A later increase in proliferation was observed at -10 d in LD cows. For both groups, cell proliferation decreased during lactation. Analysis by terminal deoxynucleotidyl transferase dUTP nick end labeling revealed that the apoptotic index in mammary epithelial cells was less in SD cows than in LD cows. Expression of IGF-II mRNA increased during the dry period and into lactation and was greater in SD cows. Expression of IGF binding protein-5 mRNA increased during lactation, but was unaffected by day length. Expression of IGF-I did not differ over time or between treatments. We concluded that exposure to SD during the dry period enhanced mammary growth relative to LD, and this may be related to increased expression of IGF-II. Treatment differences in the temporal pattern of proliferation indicated the existence of a critical period wherein photoperiod affects mammary gland development during the dry period.

Animals↗
PubMed2003

Lactation persistency: insights from mammary cell proliferation studies.

A persistent lactation is dependent on maintaining the number and activity of milk secreting cells with advancing lactation. When dairy cows are milked twice daily, the increase in milk yield from parturition to peak lactation is due to increased secretory activity per cell rather than to accretion of additional epithelial cells. After peak lactation, declining milk yield is due to loss of mammary epithelial cells by apoptosis. During lactation, only 0.3% of mammary cells proliferate in a 24-h period. Yet this proliferative rate is sufficient to replace most mammary epithelial cells by the end of lactation. Management practices can influence lactation persistency. Administration of bovine somatotropin may enhance persistency by increasing cell proliferation and turnover, or by reducing the rate of apoptosis. Increased photoperiod may also increase persistency of lactation by mechanisms that are as yet undefined. Increased milking frequency during the first weeks of lactation increases milk yield, even after return to less frequent milking, with increases of approximately 8% over the entire lactation. A mammary cell proliferation response to frequent milking during early lactation appears to be involved. Conversely, advanced pregnancy, infrequent milking, and mastitis increase death of epithelial cells by apoptosis. Regulation of mammary cell renewal provides a key to increasing persistency. Investigations to characterize epithelial cells that serve as the proliferative population in the bovine mammary gland have been initiated. Epithelial cells that stain lightly in histological sections are evident through all phases of mammary development and secretion and account for nearly all proliferation in the prepubertal gland. Characterization of these cells may provide a means to regulate mammary cell proliferation and thus to enhance persistency, reduce the effects of mastitis, and decrease the necessity for a dry period.

Animals↗
PubMed2003

Mammary epithelial proliferation and estrogen receptor alpha expression in prepubertal heifers: effects of ovariectomy and growth hormone.

The objectives of this study were to determine the effects of ovariectomy and growth hormone on mammary epithelial cell proliferation and estrogen receptor alpha (ER alpha) expression within the bovine mammary gland. Two experiments were performed. In the first experiment, eight Holstein heifer calves aged between 1 and 3 mo were ovariectomized, while six calves served as controls. At 6 mo of age, calves were treated with bromodeoxyuridine (BrdU) to label proliferating cells and sacrificed 2 h later. Coinciding with reduced mammary mass (304 +/- 25 vs. 130 +/- 21 g), proliferation of mammary epithelial cells was significantly lower in ovariectomized heifers compared to control heifers (2.24 vs. 0.25%). ER alpha expression was restricted to mammary epithelial cells and was not observed within intra-lobular stroma of parenchymal tissue. The proportion of ER alpha positive cells was significantly higher in ovariectomized heifers than in controls (36.1% +/- 2.2 vs. 46.7% +/- 2.4). In the second experiment, mammary biopsies were taken from five 6-mo-old heifers, immediately preceding and 7 d following a single injection of bovine growth hormone. Mammary epithelial cell proliferation (assessed by incorporation of 3H-thymidine) was increased by growth hormone. The proportion of ER alpha positive mammary epithelial cells was not increased by growth hormone. In conclusion, reduced mammary epithelial cell proliferation following ovariectomy was associated with an increase in ER alpha expression, whereas increased proliferation caused by bovine growth hormone was not associated with changes in the proportion of ER alpha positive cells.

Animals↗
PubMed2001

A taxonomy for diabetes educational interventions.

Diabetes education is a cornerstone of diabetes self-care management. Despite terrific progress in refining educational interventions, the diabetes literature continues to contain substantial inconsistencies in reporting the elements of educational interventions. This unnecessary variation in the quality of reporting has led to difficulties in understanding the results of educational research in diabetes. We provide a taxonomy that should prove helpful, both in the conceptual design of diabetes educational interventions and in the reporting of those interventions. An application of this taxonomy to 30 diabetes educational randomized controlled trials is presented to highlight the extent of variation in diabetes educational interventions.

Diabetes Mellitus↗
PubMed1999

Contribution of insulin-like growth factor (IGF)-I and IGF-binding protein-3 to mitogenic activity in bovine mammary extracts and serum.

Peripubertal development of the mammary gland is probably mediated by locally produced growth factors acting in concert with circulating mitogens. Our objective was to investigate the effect of recombinant human insulin-like growth factor-binding protein-3 (rhIGFBP-3) or insulin-like growth factor-I (IGF-I) antibodies on the IGF-I-related mitogenic activity of bovine serum and of mammary tissue extracts in primary mammary epithelial cell cultures. Cells were obtained from prepubertal female calf mammary tissue and cultured in three-dimensional collagen gels. An aqueous mammary parenchymal tissue extract (pooled from 20 prepubertal heifers) or serum (pooled from 3 heifers) at a concentration of 5% was added to the medium containing either rhIGFBP-3 or monoclonal or polyclonal antibodies to human IGF-I. Cell proliferation was evaluated using [methyl-3H]thymidine incorporation as a measure of DNA synthesis. Addition of mammary extracts stimulated DNA synthesis 545% compared with basal medium. Addition of serum stimulated DNA synthesis by 28%. Mitogenic activity of serum and added IGF-I was abolished by addition of rhIGFBP-3 in equimolar concentrations with IGF-I. For mammary extracts, mitogenic activity was inhibited by 35%, 50%, and 82% by the addition of rhIGFBP-3 at, respectively, 1, 2 and 4 times the molar IGF-I concentration in the extract. Addition of rhIGFBP-3 to basal medium reduced DNA synthesis by 26%, whereas IGF-I antibodies had no consistent effect. These results indicate that circulating and mammary-synthesized IGF-I and IGFBPs probably play a critical role in prepubertal development of the bovine mammary gland.

Analysis of Variance↗
PubMed1983

The epidemiology of diabetic acidosis: a population-based study.

A 12-month epidemiologic study in 1979 and 1980 of all diabetic acidosis admissions to all acute care hospitals in Rhode Island detected 152 episodes occurring in 137 persons. Eleven per cent of diabetic acidosis admissions presented in coma and the overall death-to-case ratio was 9%. Newly diagnosed diabetes accounted for 20% of these episodes, while persons having multiple episodes during the year accounted for 15% of the admissions. The annual rate of diabetic acidosis was 46 per 10,000 diabetics. Highest rates of diabetic acidosis were found for the elderly, those admitted from nursing homes and those residing in one geographic area of the state. For known diabetics with an admission for acidosis, 87% were on insulin prior to admission and 81% were nonobese. Patients seldom contacted physicians prior to admission. Insulin dose or frequency was often (40%) changed in the two weeks prior to admission. Most of the known diabetic cases of acidosis had emergency admissions for diabetes in the three-year period prior to admission and few had any structured diabetic outpatient education. Infection and noncompliance were the most frequently identified precipitants of diabetic acidosis occurring in known diabetics.

Adolescent↗
PubMed1983

An epidemiologic study of the risks associated with peripheral intravenous catheters.

As part of a standardized, multi-hospital prospective surveillance system for nosocomial infections in Rhode Island, an analysis was undertaken in March 1980-February 1982 to determine the interplay of factors that contribute to the risk of phlebitis in peripheral, non-steel, non-butterfly intravenous catheters. The authors studied 3094 patients with 5161 total episodes of peripheral intravenous catheters from day of admission until day of discharge. The overall rate of phlebitis was 2.3% (118 episodes), and the rate of intravenous catheter-associated bacteremia was 0.08% (1 definite episode, 3 possible episodes). Factors significantly associated with the occurrence of phlebitis were: underlying risk for any nosocomial infection, duration of the catheter episode, chronological order of the episode and an interaction between the latter two variables. Analysis of day-specific risk of phlebitis indicated that, for patients with low risk diagnoses, initial peripheral intravenous catheters might be left in place with relative safety for up to 96 hours. Over this time period, the day-specific risk for such patients ranged between 0.8% and 1.4%, exclusive of the first day. In all other circumstances, the current recommendation of 48-72 hours seems appropriate.

Adult↗
PubMed1980

Chlorpromazine inhibition of granulocyte superoxide production.

Superoxide production by granulocytes is a result of the activation of an NAD(P)H-dependent oxidase present in the plasma membrane. Chlorpromazine (5-50 muM) prolongs the time necessary to activation of the superoxide generating system and inhibits the extent of activation. When chlorpromazine is added after activation, there is an inhibition of further superoxide production. These effects are seen with digitonin, phorbol myristate acetate, and opsonized zymosan stimulated guinea pig and human granulocytes. Other phenothiazines (1-20 muM) and tetracaine (0.1-1.0 muM) produce similar effects. Lidocaine (1-10 mM) inhibits superoxide production but has no effect on the rate of activation. The effect of chlorpromazine on the rate of activation is reversible, but its effect on extent of activation is unaffected by extensive washing. Incubation of granulocytes with chlorpromazine results in decreased activation of the plasma membrane superoxide generating NADPH oxidase. Chlorpromazine also competes with NADPH for the membrane oxidase. These data and previously published results provide the basis of a model for the activation of the superoxide generating system.

Anesthetics, Local↗
PubMedDate not supplied

Hyperosmolarity and acidosis in diabetes mellitus: a three-year experience in Rhode Island.

OBJECTIVES: Diabetic acidosis (DA) and the diabetic hyperosmolar state (DHS) are generally considered to be two distinct clinical entities. However, clinical experience and the literature suggest that there may be some overlap. The purposes of this study were 1) to establish the proportion of overlap cases, 2) to identify any occurrence of DHS in diabetic patients under the age of 30 years (likely type I) and any occurrence of DA in diabetic patients over the age of 60 years (likely type II), 3) to describe clinical factors associated with the development of DA and DHS, and 4) to identify factors that influence the prognosis of DHS. PATIENTS AND METHODS: 613 cases were identified by retrospective chart review, using discharge information from all 15 Rhode Island community hospitals during 1986, 1987, and part of 1988. DA alone [serum glucose (glu) greater than 300 mg/dL, bicarbonate (HCO3) less than 15mEq/L, calculated total serum osmolarity (osm) less than or equal to 320 mOsm/L] was the diagnosis for 134 subjects (22%), DHS alone (glu greater than 600 mg/dL, HCO3 greater than or equal to 15mEq/L, osm greater than 320 mOsm/L), for 278 subjects (45%), and a mixed case (glu greater than 600 mg/dL, HCO3 less than 15 mEq/L, osm greater than 320 mOsm/L), for 200 subjects (33%). Information about serum or urinary ketones was available for 109 subjects who had DA alone [103 had diabetic ketoacidosis (DKA)] and 144 subjects who had mixed DA and DHS (131 had mixed DKA and DHS). All the data were also analyzed using the effective osmolarity and a cutoff of 310 mOsm/L for this alternative case definition. RESULTS: Patients with DA alone were younger (mean age 33 years) and patients with DHS alone were older (mean age 63 years). However, 28 (10%) of the 278 cases of DHS alone and 72 (36%) of the 200 cases of mixed DA and DHS occurred in patients under the age of 30. Eighteen cases (13%) of DA alone and 62 cases (31%) of mixed DA and DHS occurred in patients over the age of 60. The results were not substantially changed when effective osmolarity greater than 310 mOsm/L was used to define hyperosmolarity and when only cases with documented DKA were included. An infection was the most common precipitating factor of DA (30%), DHS (27%), and mixed cases (32%). Other common associated factors included noncompliance with treatment (20% for DA, 12% for DHS, and 22% for mixed cases) and previously undiagnosed diabetes (24% for DA, 18% for DHS, and 10% for mixed cases). Nursing home residents accounted for 0.7% of DA cases, 18% of DHS cases, and 4.5% of mixed cases. Mortality was 4% for DA, 12% for DHS, and 9% for mixed cases. The mortality for DHS is the lowest reported in the literature, continuing a downward trend that began in the 1970s. Nonsurvival was associated with older age, higher osmolarity, and nursing home residence. Survival was associated with the presence of an infection. CONCLUSIONS: 1) many patients experience mixed DA (DKA) and DHS rather than either condition alone, 2) both DA (DKA) and DHS occur in young and old diabetic persons, 3) infection is the most common predisposing factor for either condition, and 4) higher osmolarity, older age, and nursing home residence are associated with nonsurvival in DHS.

Adult↗
PubMedDate not supplied

Incidence and hospitalization patterns of insulin-dependent diabetes mellitus.

Data from a statewide insulin-dependent diabetes mellitus (IDDM) registry in Rhode Island show that IDDM affects young adults (20-29 yr) as frequently as adolescents and teenagers (10-19 yr). Overall incidence less than 30 yr was 14/100,000 population. Peak incidence occurred at 10-14 yr (19/100,000 population). Poor diabetic control and infection accounted for 46-62% of hospitalizations among 275 known diabetic persons. Despite a 10-yr mean duration of diabetes, only 31% of hospitalized diabetic persons less than 30 yr of age reported ever having received outpatient diabetes education of two or more hours. Readmissions 1 yr after initial registration were more frequent for known (43%) than new-onset (18%) IDDM cases. Increased risk of readmission for both groups was associated with a poverty socioeconomic status. Total direct hospitalization costs for IDDM in persons under 30 yr of age in Rhode Island was $530,000 per year of $2,245 per patient.

Adolescent↗