Cyclical heat stress during lactation influences the microstructure of the bovine mammary gland.

This study aimed to evaluate the impact of heat stress on mammary epithelial cell (MEC) losses into milk, secretory mammary tissue structure, and mammary epithelial cell activity. Sixteen multiparous Holstein cows (632 ± 12 kg BW) approximately 100 d in milk housed in climate-controlled rooms were paired by body weight and randomly allocated to one of 2 treatments, heat stress (HS) or pair feeding thermoneutral (PFTN) using 2 cohorts. Each cohort was subjected to 2 periods of 4 d each. In period 1, both treatments had ad libitum access to a common total mixed ration and were exposed to a controlled daily temperature-humidity index (THI) of 64. In period 2, HS cows were exposed to controlled cyclical heat stress (THI: 74 to 80), while PFTN cows remained at 64 THI and daily dry matter intake was matched to HS. Cows were milked twice daily, and milk yield was recorded at each milking. Individual milk samples on the last day of each period were used to quantify MEC losses by flow cytometry using butyrophilin as a cell surface marker. On the final day of period 2, individual bovine mammary tissue samples were obtained for histomorphology analysis, assessment of protein abundance, and evaluation of gene expression of targets associated with cellular capacity for milk and milk component synthesis, heat response, cellular proliferation, and autophagy. Statistical analysis was performed using the GLIMMIX procedure of SAS. Milk yield was reduced by 4.3 kg by HS (n = 7) compared with PFTN (n = 8). Independent of treatment, MEC in milk averaged 174 cells/mL (2.9% of total cells). There was no difference between HS vs. PFTN cows for MEC shed or concentration in milk. Alveolar area was reduced 25% by HS, and HS had 4.1 more alveoli than PFTN. Total number of nucleated MEC per area were greater in HS (389 ± 1.05) compared with PFTN (321 ± 1.05); however, cell number per alveolus was similar between groups (25 ± 1.5 vs. 26 ± 1.4). There were no differences in relative fold expression for GLUT1, GLUT8, CSN2, CSN3, LALBA, FASN, HSPA5, and HSPA8 in HS compared with PFTN. Immunoblotting analyses showed a decrease abundance for phosphorylated STAT5 and S6K1, and an increase in LC3 II in HS compared with PFTN. These results suggest that even if milk yield differences and histological changes occur in the bovine mammary gland after 4 d of heat exposure, MEC loss into milk, nucleated MEC number per alveolus, and gene expression of nutrient transport, milk component synthesis, and heat stress related targets are unaffected. In contrast, the abundance of proteins related to protein synthesis and cell survival decreased significantly, while an upregulation of proteins associated with autophagy in HS compared with PFTN.

Relationships between gastrointestinal permeability, heat stress, and milk production in lactating dairy cows.

Heat stress (HS) is a global issue that decreases farm profits and compromises animal welfare. To distinguish between the direct and indirect effects of HS, 16 multiparous Holstein cows approximately 100 DIM were assigned to one of 2 treatments: pair fed to match HS cow intake, housed in thermoneutral conditions (PFTN, n = 8) or cyclical HS (n = 8). All cows were subjected to 2 experimental periods. Period 1 consisted of a 4 d thermoneutral period with ad libitum intake. During period 2 (P2), the HS cows were housed in cyclical HS conditions with a temperature-humidity index (THI) ranging from 76 to 80 and the PFTN cows were exposed to a constant THI of 64 for 4 d. Dry matter intake of the PFTN cows was intake matched to the HS cows. Milk yield, milk composition, rectal temperature, and respiration rate were recorded twice daily, blood was collected daily via a jugular catheter, and cows were fed twice daily. On d 3 of each period, Cr-EDTA and sucralose were orally administered and recovered via 24 h total urine collection to assess gastrointestinal permeability. All data were analyzed using the GLIMMIX procedure in SAS. The daily data collected in P1 was averaged and used as a covariate if deemed significant in the model. Heat stress decreased voluntary feed intake by 35% and increased rectal temperature and respiration rate (38.4°C vs. 39.4°C and 40 vs. 71 respirations/min, respectively). Heat stress reduced DMI by 35%, which accounted for 66% of the decrease in milk yield. The yields, and not concentrations, of milk protein, fat, and other solids were lower in the HS cows on d 4 of P2. Milk urea nitrogen was higher and plasma urea nitrogen tended to be higher on d 3 and d 4 of HS. Glucose was 7% lower in the HS cows and insulin was 71% higher in the HS cows than the PFTN cows on d 4 of P2. No difference in lipopolysaccharide-binding protein was observed. Heat stress cows produced 7 L/d more urine than PFTN cows. No differences were detected in the urine concentration or percentage of the oral dose recovered for Cr-EDTA or sucralose. In conclusion, HS was responsible for 34% of the reduction of milk yield. The elevated MUN and the tendency for elevated plasma urea nitrogen indicate a whole-body shift in nitrogen metabolism. No differences in gastrointestinal permeability or lipopolysaccharide-binding protein were observed. These results indicate that, under the conditions of this experiment, activation of the immune system by gut-derived lipopolysaccharide was not responsible for the decreased milk yield observed during HS.

Persistence of sugars used for intestinal permeability measures in an in vitro rumen environment.

Orally administered synthetic sugars are routinely used as markers of intestinal permeability in nonruminants and young calves, but not adult ruminants, likely because of uncertainty surrounding degradation of such sugar markers (e.g., d-mannitol, sucralose, lactulose) in the rumen. The objective was to evaluate persistence of d-mannitol, sucralose, and lactulose in a closed in vitro rumen fermentation system over 48 h. The null hypothesis was that sugar concentration would not be affected by time. Rumen contents were collected and processed under anerobic conditions a total of 12 times from a ruminally cannulated lactating Holstein cow. These 12 rumen samplings reflect 4 in vitro experiments (d-mannitol, sucralose, lactulose, and d-glucose as a positive methodological control), each replicated 3 times. For each replication, filtered rumen contents and rumen buffer (1:3; vol/vol) were added to a series of six 500-mL flasks, each containing 3 filter bags. Each filter bag contained 500 mg of ground total mixed ration (94.2% dry matter; 15.2% crude protein, 40.9% neutral detergent fiber, 3.9% fat, and 6.2% ash, dry matter basis) and three 5-mm glass beads. The 6 flasks represented 0, 6, 12, 24, and 48 h time points, and a 48-h negative control flask. A single sugar was tested during each experimental replicate. Final flask concentrations of each sugar were 4.07 mg/mL d-glucose, 1.99 mg/mL d-mannitol, 2.17 mg/mL sucralose, or 3.10 mg/mL lactulose. Flasks were incubated under anerobic conditions at 39°C where they remained undisturbed until the designated time of removal (0, 6, 12, 24, or 48 h). At removal, an aliquot of each flask was removed and sugar concentration was quantified by HPLC-mass spectrometry. Data for each experiment were analyzed using an ANOVA model that included the single fixed effect of time (0, 6, 12, 24, or 48 h); flask within replicate was the random term. Lactulose was not resolved in any samples due to interfering components within the sample matrix; no lactulose data are presented. As expected, positive methodological control of glucose decreased to negligible concentrations by 6 h of in vitro incubation. d-Mannitol followed the same pattern as glucose, which was different from our hypothesis. The interpretation is that d-mannitol is degraded in the in vitro rumen culture system and, by extension, is therefore not a viable choice to use in in vivo intestinal permeability tests in adult ruminants when dosed orally. As hypothesized, sucralose concentration did not change over 48 h of incubation in a closed in vitro rumen fermentation system. This suggests feasibility of orally dosed sucralose in adult ruminants as a rumen-inert marker of intestinal permeability with subsequent analysis of biological samples (e.g., urine, blood) by HPLC-mass spectrometry.

Algorithm development for individualized precision feeding of supplemental top dresses to influence feed efficiency of dairy cattle.

Individualized, precision feeding of dairy cattle may contribute to profitable and sustainable dairy production. Feeding strategies targeted at optimizing efficiency of individual cows, rather than groups of animals with similar characteristics, is a logical goal of individualized precision feeding. However, algorithms designed to make feeding recommendations for specific animals are scarce. The objective of this study was to develop and test 2 algorithms designed to improve feed efficiency of individual cows by supplementing total mixed rations (TMR) with varying types and amounts of top-dressed feedstuffs. Twenty-four Holstein dairy cows were assigned to 1 of 3 treatment groups as follows: a control group fed a common TMR ad libitum, a group fed individually according to algorithm 1, and a group fed individually according to algorithm 2. Algorithm 1 used a mixed-model approach with feed efficiency as the response variable and automated measurements of production parameters and top-dress type as dependent variables. Cow was treated as a random effect, and cow by top-dress interactions were included if significant. Algorithm 2 grouped cows based on top-dress response efficiency structure using a principal components and k-means clustering. Both algorithms were trained over a 36-d experimental period immediately before testing, and were updated weekly during the 35-d testing period. Production performance responses for dry matter intake (DMI), milk yield, milk fat percentage and yield, milk protein percentage and yield, and feed efficiency were analyzed using a mixed-effects model with fixed effects for feeding algorithm, top dress, week, and the 2- and 3-way interactions among these variables. Milk protein percentage and feed efficiency were significantly affected by the 3-way interaction of top dress, algorithm, and week, and DMI tended to be affected by this 3-way interaction. Feeding algorithm did not affect milk yield, milk fat yield, or milk protein yield. However, feeding costs were reduced, and hence milk revenue increased on the algorithm-fed cows. The efficacy of feeding algorithms differed by top dress and time, and largely relied on DMI shifts to modulate feed efficiency. The net result, for the cumulative feeding groups, was that cows in the algorithm 1 and 2 groups earned over $0.45 and $0.70 more per head per day in comparison to cows on the TMR control, respectively. This study yielded 2 candidate approaches for efficiency-focused, individualized feeding recommendations. Refinement of algorithm selection, development, and training approaches are needed to maximize production parameters through individualized feeding.

Predicting the distance for nasojejunal tube insertion in children.

ISSUES AND PURPOSE: As no consistent predictor of insertion tube distance has been determined for intestinal feeding tubes and fluoroscopic placement is very expensive, this study sought a reliable method of blind placement. DESIGN AND METHODS: This cross-sectional study measured the internal distance from the lip to the pylorus in 387 children undergoing upper gastrointestinal endoscopy and compared those measurements to the external distances measured from the nose around the ear to the 10th rib and lip around the ear to the 10th rib. RESULTS: Regression equations using height fitted in four age groups were the best predictors of the internal pyloric distances. PRACTICE IMPLICATIONS: Predicting this distance with height may help healthcare providers be more successful in blind placement of intestinal feeding tubes. A table of predicted nasointestinal tube insertion distances is included.

Hepatitis C, E, F, G, and non-A-G.

Inflammation of the liver is known as hepatitis. Six or seven viruses, hepatitis viruses A through G, are responsible for most cases of viral hepatitis. In this second of a series of three articles, current knowledge regarding hepatitis C, E, F, G, and non-A-G is reviewed. Up to 80% of patients infected with hepatitis C progress to chronic liver disease. Hepatitis E is an enteric hepatitis that is endemic in Asia. Hepatitis F may be a mutant hepatitis C. Hepatitis G is a posttransfusion hepatitis. Non-A-G hepatitis consists of all of the hepatitis viruses awaiting identification. Up-to-date information regarding each of these types of hepatitis viruses is presented herein, because every phase of patient care improves when health care professionals are knowledgeable regarding the illnesses of their clients.

Autoimmune hepatitis.

Autoimmune hepatitis (AIH) is a necro-inflammatory disease that, untreated, carries a 3-year mortality rate of approximately 50%. In this last of a series of three articles, current knowledge regarding AIH is reviewed. The mode of presentation of AIH is variable: insidious onset with few if any symptoms, presenting with symptoms indistinguishable from that of any acute viral hepatitis, or onset with fulminate hepatitis. In AIH, hepatocytes become injured by various agents (such as a viral infection) and become antigenic, leading to a self-perpetuating antigen-antibody response with subsequent chronic liver disease. AIH is the only type of hepatitis that is responsive to corticosteroids. Occasionally, AIH develops after liver transplantation.

A comparison of the effect of three sedatives on esophageal sphincters in cats.

BACKGROUND/AIMS: Children 5 years old and younger often require sedation for esophageal motility studies (EMS). At our institution, an intramuscular cocktail of meperidine, promethazine and chlorpromazine (MPC) has been used as the standard sedative for young children undergoing EMS. Administering the intramuscular sedative may, however, be more traumatic to the child than the procedure. Moreover, its effect on esophageal motility is not known and prolonged sedation is common. The aim of this study was to determine the effects of MPC and two orally-administered sedatives on esophageal sphincter function, using the cat model, with a goal to identify a potentially suitable orally-administered sedative for use in young children requiring sedation for EMS. METHODS: We measured upper (UESP) and lower (LESP) esophageal sphincter pressures in 25 cats initially without sedation, and then following sedation with midazolam, chloral hydrate and MPC. The results were compared. RESULTS: All three sedatives significantly decreased LESP compared to the control (p<0.05). Midazolam decreased LESP the most; however, the difference from the other sedatives did not reach statistical significance. All three sedatives decreased UESP, compared to control, but the differences were not statistically significant. Of the two oral sedatives, chloral hydrate had the least effect on the esophageal sphincters although its effect was not statistically different from that of midazolam. CONCLUSIONS: Ethically appropriate studies are needed to determine which oral sedative would be most beneficial for use in sedating children undergoing esophageal motility studies. Until studies can be done, the choice between chloral hydrate and midazolam should be based on the experience and comfort of the attending physician with regard to the potential side effects of the medications.

Examination of gavage tube placement in children.

ISSUES AND PURPOSE: A primary issue in ensuring safe and effective enteral feeding by tube is achieving and maintaining correct tube position. This study was conducted to determine the prevalence of tube placement errors, risk factors associated with these errors, and accuracy of commonly used bedside placement-screening methods. DESIGN AND METHODS: In this descriptive study, 39 hospitalized children having one or more types of enteral tubes were studied prospectively. Tube placement was assessed across time, using three common placement-screening methods compared to radiographs. RESULTS: Tube placement error occurred in 43.5% of tubes at least once during the observation period. Children who were comatose or semicomatose, were inactive, had swallowing problems, or had Argyle tubes were more likely to have tube placement errors. PRACTICE IMPLICATIONS: Findings suggest that radiographs to document tube placement may be needed, at least on initial enteral tube insertion.

Prevalence of immunoglobulin G to Helicobacter pylori among endoscopy nurses/technicians.

The purpose of this study was to compare the prevalence of Helicobacter pylori (HP) seropositivity among gastroenterology nurses and technicians with that of the general population. Nurses attending the 1996 Indiana Society of Gastroenterology Nurses and Associates Spring and Fall Education Courses were asked to complete a checklist regarding employment, current symptoms, and use of universal precautions, and to have 3 ml blood drawn. These 138 blood specimens as well as 112 serum samples from generally age- and sex-matched blood donors (representing the general population) underwent qualitative HP antibody testing. Results showed that the prevalence of seropositivity for immunoglobulin G (IgG) antibody for HP among the gastroenterology nurses and technicians was 19 of 138 (13.8%), which was less than that of the blood donor control group, whose seropositivity was 20 of 112 (17.9%). However, this difference failed to reach statistical significance. Seropositivity tended to increase with age, but there was no association between clinical symptomatology and seropositivity. Likewise, there was no difference in seropositivity between nurses assisting with endoscopic procedures for more than 10 years and those assisting for less than 10 years. Although the differences were not significant, these findings refute those of an earlier study in which the researchers found 122 gastroendoscopists and endoscopy nurses significantly more likely to be positive for HP antibodies. Therefore, the findings reported here provide important information.

Hepatitis A, B, and D.

Inflammation of the liver is known as hepatitis. Six or seven viruses, hepatitis A-G, are responsible for the majority of cases of viral hepatitis. All of the types of hepatitis present with the same flu-like symptoms. In this first of a series of three articles, current knowledge regarding hepatitis A, B, and D will be reviewed. Fifty percent of hepatitis cases are due to hepatitis A. Hepatitis B is considered a sexually transmitted disease. Hepatitis D is an incomplete virus found accompanying Hepatitis B. Every phase of patient care improves when health care professionals are knowledgeable regarding their clients' illnesses. This article presents our current scientific understanding of hepatitis A, B, and D viruses.

Prevalence of feeding tube placement errors & associated risk factors in children.

PURPOSE: The purpose of this study was to determine the prevalence of feeding tube placement errors in children. DESIGN AND METHODS: The hospital records of 201 children having both an enteral tube and at least one radiograph showing tube placement were retrospectively reviewed. Chart review was also used to determine the risk factors associated with these errors. Tube placement error was defined as tube tip or orifices in the esophagus or intestine (if the tube was supposed to be in the stomach) or tip or orifices in the esophagus or stomach (if the tube was supposed to be in the intestine.) RESULTS: On the first day, a radiograph documenting tube placement showed that 32 of the 201 children (15.9%) had tube placement errors. Overall, 53 tube placement errors were evident during the 385 observation days on which radiographs were obtained (13.8%). Of the 201 children, 42 (20.9%) had experienced tube placement errors at some time during the period reviewed. Over all radiograph days, activity level was independently related to radiographic tube placement (p = < 0.02), with more errors among active children. Also, classification regression tree analysis showed that age, level of consciousness (alert or comatose versus semicomatose), abdominal distention, vomiting, and orogastric tubes were associated with more tube placement errors. NURSING IMPLICATIONS: Nurses need to be especially careful in assessing tube placement if the pediatric client has one or more of the identified risk factors. Health care providers need to carefully weigh the benefits and risks of feeding by nasal or oral enteral tubes versus the benefits and risks of feeding by endoscopically or surgically placed enteral tubes.

ALARA study of teaching effectiveness on reducing radiation exposure.

The purpose of this study was to measure the effectiveness of radiation safety instruction and the impact on radiation film badge levels. A convenience sample of 144 endoscopy nurses and technicians was pretested for radiation safety knowledge, given a course in radiation safety, and then posttested immediately after the course and then 6 months later. Radiation badges were analyzed for radiation exposure at preinstruction, 1 month postinstruction, and 6 months postinstruction. Results showed that the instruction was effective. There was only a slight decrease in radiation badge readings; the decrease, however, was not statistically significant.

Development of the Vulnerability Scale.

Developing a new data collection scale is a time- and labor-intensive process. Initially, the items may be developed from a review of the appropriate literature, clinical expertise of the developer, in-depth interviewing of potential subjects, or any combination of these techniques. Next, evidence of the validity (content-related, construct-related, and criterion-related), internal consistency reliability, and reliability of the scale must be established. The new scale may be administered to one or two small samples (pilot studies) before it is ready for use with a larger group. Gathering evidence regarding the scale's validity and reliability with different groups and consequent revision are ongoing processes. In this article, the authors describe how this process was followed in developing the Vulnerability Scale.

What is the prevalence of feeding tube placement errors and what are the associated risk factors?

Enteral nutrition, given through feeding tubes to patients with intact gastrointestinal tracts who are unable to eat enough orally to sustain themselves, remains an important component of supportive care. Feeding by a soft, small-bore tube passed through the nose or mouth is a more cost-effective means of providing enteral nutrition than either percutaneously or surgically placed gastrostomy tubes or central venous catheters. However, tube feeding is not without problems. The prevalence of tube placement errors reported in the literature varies from 1.3% to 50% in adults. Transpyloric tubes are difficult to place initially and correct positioning is also difficult to maintain. All types of small-bore tubes dislocate easily, frequently with no outward sign that the dislocation has occurred. Risk factors found to be related to feeding tube misplacement on insertion in adults include altered level of consciousness, altered swallowing mechanisms, and upper airway intubation. Those related to spontaneous tube displacement include altered level of consciousness, upper airway intubation, coughing, tracheal suctioning, and restlessness.

Society of Gastroenterology Nurses and Associates, Inc. (SGNA) Endoscopic Disinfectant Survey results compared with control group.

Disinfectant surveys from responding members of the American Society of Postanesthesia Nurses were divided into two groups based on whether or not they considered themselves to be exposed to disinfectants in their work environment. Their survey responses were then compared with those obtained previously from members of the Society of Gastroenterology Nurses and Associates, Inc., who were regularly exposed to 2% alkaline glutaraldehyde in the work setting. There were significant differences among the groups in the percentage of respondents who reported having headaches, eye irritations, respiratory problems, shortness of breath, rashes, memory loss, mood swings, and fatigue. These findings support the association of these complaints with 2% alkaline glutaraldehyde exposure. In contrast, there were no significant differences among the groups in the percentage of respondents who reported having asthma, rhinitis, chest pain, nausea, diarrhea, muscle/joint pain, visual disturbances, or dermatitis.

A quality assurance monitor on preparation for outpatient lower endoscopic procedures.

A two-phase quality assurance monitor was performed with a pediatric outpatient population to determine how well the current preparation of Fleet Phospho-Soda, Fleet enemas, and diet modification cleaned the colon. We studied 99 patients in Phase 1, implemented changes, and then studied 99 patients in Phase 2. Phase 2 found increasing age to be significantly related to decreasing cleanliness of the transverse colon, ascending colon, and cecum, and increasing weight was found to be significantly related to decreasing cleanliness of the cecum. Phase 2 also found the second enema to be significant for increasing cleanliness of the rectum.

Prevalence of gastric cancer in a large group of healthcare workers routinely exposed to Helicobacter pylori.

Secondary data analysis of the Society of Gastroenterology Nurses and Associates Endoscopic Disinfectant Survey was undertaken to answer the question, "What was the prevalence of gastric cancer among endoscopy personnel who were routinely exposed to Helicobacter pylori (HP) in their work environment?" This large sample of healthcare personnel (4,001) was occupationally exposed to both endoscopic disinfectants and HP. There is a known positive relationship between the prevalence of HP infection, gastritis, and gastric cancer. Results indicated that zero respondents reported gastric cancer in this sample.

Gilbert syndrome.

Two or three times a year, a healthy patient (> 1 year old) with mild unconjugated hyperbilirubinemia as the only abnormality on routine liver function testing will be referred to the gastroenterologist. A diagnosis of Gilbert Syndrome (GS) is made, and the patient may or may not be seen in the clinic or office because GS is a benign condition. Either way, the nurse needs to understand the pathophysiology of this condition so he/she can provide necessary patient/family education. The purpose of this article is to review the existing literature on GS and to summarize it in a manner useful to both nurses and families.