Hospital-acquired Anemia in Critically Ill Dogs and Cats: A Multi-Institutional Study

BACKGROUND

Hospital-acquired anemia is commonly described in people but limited information currently is available regarding its prevalence in animals.

HYPOTHESIS/OBJECTIVES

Assess the prevalence of hospital-acquired anemia in hospitalized critically ill dogs and cats, and examine its relationship with phlebotomy practices, transfusion administration, and survival to discharge.

ANIMALS

Eight hundred and fifty-one client-owned animals (688 dogs and 163 cats).

METHODS

A multicenter, observational study was conducted in which packed cell volume (PCV) was recorded at the time of admission and on subsequent hospitalization days. Signalment, number of blood samples obtained, underlying disease, whether or not blood products were administered, duration of hospitalization, and survival to discharge were recorded.

RESULTS

Admission anemia prevalence was 32%, with overall prevalence during the hospitalization period of 56%. The last recorded PCV was significantly lower than the admission PCV for both dogs (admission PCV, 42% [range, 6-67%]; last recorded PCV, 34% [range, 4-64%], P < .0001) and cats (admission PCV, 31% [range, 6-55%]; last recorded PCV, 26% [range, 10-46%], P < .0001). Patients that developed anemia had significantly more blood samples obtained (nonanemic, 5 blood samples [range, 2-54]; anemic, 7 blood samples [range, 2-49], P < .0001). Hospitalized cats were significantly more likely to develop anemia compared to dogs (P < .0001), but anemic dogs were significantly less likely to survive to discharge (P = .0001). Surgical patients were at higher risk of developing hospital-acquired anemia compared to medical patients (OR, 0.63; 95% CI, 0.4-0.9; P = .01).

CONCLUSIONS AND CLINICAL RELEVANCE

Hospital-acquired anemia occurred frequently, especially in surgical patients. Additional studies focused on the direct effect of phlebotomy practices on the likelihood of anemia development in hospitalized animals are warranted.

Qualitative and Quantitative Characteristics of the Electroencephalogram in Normal Horses during Administration of Inhaled Anesthesia

BACKGROUND

The effects of anesthesia on the equine electroencephalogram (EEG) after administration of various drugs for sedation, induction, and maintenance are known, but not that the effect of inhaled anesthetics alone for EEG recording.

OBJECTIVE

To determine the effects of isoflurane and halothane, administered as single agents at multiple levels, on the EEG and quantitative EEG (qEEG) of normal horses.

ANIMALS

Six healthy horses.

METHODS

Prospective study. Digital EEG with video and quantitative EEG (qEEG) were recorded after the administration of one of the 2 anesthetics, isoflurane or halothane, at 3 alveolar doses (1.2, 1.4 and 1.6 MAC). Segments of EEG during controlled ventilation (CV), spontaneous ventilation (SV), and with peroneal nerve stimulation (ST) at each MAC multiple for each anesthetic were selected, analyzed, and compared. Multiple non-EEG measurements were also recorded.

RESULTS

Specific raw EEG findings were indicative of changes in the depth of anesthesia. However, there was considerable variability in EEG between horses at identical MAC multiples/conditions and within individual horses over segments of a given epoch. Statistical significance for qEEG variables differed between anesthetics with bispectral index (BIS) CV MAC and 95% spectral edge frequency (SEF95) SV MAC differences in isoflurane only and median frequency (MED) differences in SV MAC with halothane only.

CONCLUSIONS AND CLINICAL IMPORTANCE

Unprocessed EEG features (background and transients) appear to be beneficial for monitoring the depth of a particular anesthetic, but offer little advantage over the use of changes in mean arterial pressure for this purpose.

Electroencephalogram of Healthy Horses During Inhaled Anesthesia

Background

Previous study of the diagnostic validity of electroencephalography (EEG) to detect abnormalities in equine cerebral cortical function relied on the administration of various drugs for sedation, induction, and maintenance of general anesthesia but used identical criteria to interpret recordings.

Objectives

To determine the effects of 2 inhalation anesthetics on the EEG of healthy horses.

Animals

Six healthy horses.

Methods

Prospective study. After the sole administration of one of either isoflurane or halothane at 1.2, 1.4, and 1.6 times the minimum alveolar concentration, EEG was recorded during controlled ventilation, spontaneous ventilation, and nerve stimulation.

Results

Burst suppression was observed with isoflurane, along with EEG events that resembled epileptiform discharges. Halothane results were variable between horses, with epileptiform‐like discharges and bursts of theta, alpha, and beta recorded intermittently. One horse died and 2 were euthanized as the result of anesthesia‐related complications.

Conclusions and Clinical Importance

The results of this study indicate that the effects of halothane and isoflurane on EEG activity in the normal horse can be quite variable, even when used in the absence of other drugs. It is recommended that equine EEG be performed without the use of these inhalation anesthetics and that general anesthesia be induced and maintained by other contemporary means.

Therapeutic plasma concentrations of epsilon aminocaproic acid and tranexamic acid in horses

BACKGROUND

Antifibrinolytic drugs such as epsilon aminocaproic acid (EACA) and tranexamic acid (TEA) are used to treat various bleeding disorders in horses. Although horses are hypofibrinolytic compared to humans, dosing schemes have been derived from pharmacokinetic studies targeting plasma concentrations in humans.

HYPOTHESIS/OBJECTIVES

We hypothesized therapeutic plasma concentrations of antifibrinolytic drugs in horses would be significantly lower than in humans. Our objective was to use thromboleastography (TEG) and an in vitro model of hyperfibrinolysis to predict therapeutic concentrations of EACA and TEA in horses and humans.

ANIMALS

Citrated plasma collected from 24 random source clinically healthy research horses. Commercial pooled human citrated plasma with normal coagulation parameters was purchased.

METHODS

Minimum tissue plasminogen activator (tPA) concentration to induce complete fibrinolysis within 10 minutes was determined using serial dilutions of tPA in equine plasma. Results used to create an in vitro hyperfibrinolysis model with equine and human citrated plasma, and the minimum concentrations of EACA and TEA required to completely inhibit fibrinolysis for 30 minutes (estimated therapeutic concentrations) determined using serial dilutions of the drugs.

RESULTS

Estimated therapeutic concentrations of EACA and TEA were significantly lower in horses (5.82; 95% CI 3.77-7.86 μg/mL and 0.512; 95% CI 0.277-0.748 μg/mL) than in humans (113.2; 95% CI 95.8-130.6 μg/mL and 11.4; 95% CI 8.62-14.1 μg/mL).

CONCLUSIONS AND CLINICAL IMPORTANCE

Current dosing schemes for EACA and TEA in horses may be as much as 20× higher than necessary, potentially increasing cost of treatment and risk of adverse effects.

Metastatic adenocarcinoma arising from a small bowel duplication cyst

A case report of adenocarcinoma arising from a small bowel mesenteric cyst is presented. A discussion and review of the relevant literature then follows.

Beta(3)-adrenoceptor agonist-induced increases in lipolysis, metabolic rate, facial flushing, and reflex tachycardia in anesthetized rhesus monkeys

The effects of two beta(3)-adrenergic receptor agonists, (R)-4-[4-(3-cyclopentylpropyl)-4,5-dihydro-5-oxo-1H-tetrazol-1-yl]-N-[4-[2-[[2-hydroxy-2-(3-pyridinyl)ethyl]amino]ethyl]phenyl]benzenesulfonamide and (R)-N-[4-[2-[[2-hydroxy-2-(3-pyridinyl)- ethyl]amino]ethyl]phenyl]-1-(4-octylthiazol-2-yl)-5-indolinesulfonamide, on indices of metabolic and cardiovascular function were studied in anesthetized rhesus monkeys. Both compounds are potent and specific agonists at human and rhesus beta(3)-adrenergic receptors. Intravenous administration of either compound produced dose-dependent lipolysis, increase in metabolic rate, peripheral vasodilatation, and tachycardia with no effects on mean arterial pressure. The increase in heart rate in response to either compound was biphasic with an initial rapid component coincident with the evoked peripheral vasodilatation and a second more slowly developing phase contemporaneous with the evoked increase in metabolic rate. Because both compounds exhibited weak binding to and activation of rhesus beta(1)-adrenergic receptors in vitro, it was hypothesized that the increase in heart rate may be reflexogenic in origin and proximally mediated via release of endogenous norepinephrine acting at cardiac beta(1)-adrenergic receptors. This hypothesis was confirmed by determining that beta(3)-adrenergic receptor agonist-evoked tachycardia was attenuated in the presence of propranolol and in ganglion-blocked animals, under which conditions there was no reduction in the evoked vasodilatation, lipolysis, or increase in metabolic rate. It is not certain whether the beta(3)-adrenergic receptor-evoked vasodilatation is a direct effect of compounds at beta(3)-adrenergic receptors in the peripheral vasculature or is secondary to the release or generation of an endogenous vasodilator. Peripheral vasodilatation in response to beta(3)-adrenergic receptor agonist administration was not attenuated in animals administered mepyramine, indomethacin, or calcitonin gene-related peptide(8-37). These findings are consistent with a direct vasodilator effect of beta(3)-adrenergic receptor agonists.

The influence of queen age and quality during queen replacement in honeybee colonies

Honeybee, Apis mellifera, colonies replace their queens by constructing many queen cells and then eliminating supernumerary queens until only one remains. The ages of the queens and the variation in their reproductive potential are important factors in the outcome of such events. Selection would favour colonies that requeen as quickly as possible to minimize the brood hiatus, therefore selecting for queens reared from older larvae. Conversely, reproductive potential (queen 'quality') is maximized by rearing queens from younger larvae. This potential trade-off was tested during two phases of queen replacement, namely queen rearing and polygyny reduction. Our results suggest that queen age is a significant element during both queen rearing and polygyny reduction, whereas queen quality, at least to the magnitude tested in this experiment, has little impact on the outcome of either process. The rate of queen replacement therefore appears to be an important factor in the honeybee life cycle, and further mechanisms of potential importance during this life history transition are discussed. Copyright 2000 The Association for the Study of Animal Behaviour.

Sensory gating in chronic posttraumatic stress disorder: reduced auditory P50 suppression in combat veterans

BACKGROUND

Posttraumatic stress disorder (PTSD) may be associated with a general impairment of cognitive function that extends beyond the processing of trauma-specific stimuli. Suppression of the auditory P50 response to repeated stimuli occurs in normal subjects and reflects the central nervous system's ability to screen out repetitive stimuli, a phenomenon referred to as sensory gating. This study examines P50 sensory gating to nonstartle auditory stimuli in PTSD subjects and normal controls.

METHODS

P50 generation and gating were studied using a conditioning/testing paradigm in 15 male subjects with PTSD and 12 male controls. P50 test/conditioning (T/C) ratios were estimated using the Singular Value Decomposition method.

RESULTS

The amplitude of the P50 response to the conditioning stimulus did not differ in subjects with PTSD compared to normal controls. The P50 T/C ratio is increased in PTSD subjects (mean = .408, SD = .275) as compared to the controls (mean = .213, SD = .126, two tailed t, p = .024).

CONCLUSIONS

This study provides evidence that PTSD is associated with impaired gating to nonstartle trauma-neutral auditory stimuli.

Intra-hemispheric alpha coherence decreases with increasing cognitive impairment in HIV patients

Inter-hemispheric and intra-hemispheric canonical coherences in the alpha range between EEG signals collected from frontal and posterior groups of electrodes were estimated for 38 HIV positive subjects and 23 uninfected controls. Neuropsychological testing was used to categorize the degree of cognitive impairment evident in each of the subjects. A linear regression analysis provided evidence that intra-hemispheric coherence decreased with increasing cognitive impairment in impaired HIV+ subjects, as measured by a Global Impairment Score (GIS). There was no evidence that cognitively unimpaired HIV+ subjects differed in coherence when compared to uninfected control subjects. Severely impaired HIV+ subjects showed significantly decreased coherence compared to uninfected controls. These data contradict previous work demonstrating increased intra-hemispheric and inter-hemispheric alpha coherence in impaired HIV subjects. In addition, they provide evidence that intra-hemispheric (and possibly inter-hemispheric) disconnection is associated with cognitive impairment in HIV.

Improved method for computation of potentials in a realistic head shape model

The Lead Field Analysis (LFA) algorithm, a new computational technique for the calculation of potentials on the surface of a realistic head shaped volume conductor model based on the Boundary Element Method and the Reciprocity Theorem, is presented. The new algorithm, in comparison to the Standard Boundary Element Method, offers improved computational efficiency and lower storage requirements. It also yields more accurate surface potential results in the face of varying dipole source locations for a head shape Boundary Element model with a given number of nodes. Additionally, the algorithm results in quasi-analytic expressions of the derivatives of the surface potential with respect to the location of the sources, allowing the use of optimization techniques with better convergence properties. A set of simulations demonstrating the increased robustness of the LFA Algorithm in the face of varying dipole source parameters is also described.

Phorbol esters induce death in MCF-7 breast cancer cells with altered expression of protein kinase C isoforms. Role for p53-independent induction of gadd-45 in initiating death

Protein kinase C (PKC) modulates growth, differentiation and apoptosis in a cell-specific fashion. Overexpression of PKC-alpha in MCF-7 breast cancer cells (MCF-7-PKC-alpha cell) leads to expression of a more transformed phenotype. The response of MCF-7 and MCF-7-PKC-alpha cells to phorbol esters (TPA) was examined. TPA-treated MCF-7 cells demonstrated a modest cytostatic response associated with a G1 arrest that was accompanied by Cip1 expression and retinoblastoma hypophosphorylation. While p53 was detected in MCF-7 cells, evidence for TPA-induced stimulation of p53 transcriptional activity was not evident. In contrast, TPA treatment induced death of MCF-7-PKC-alpha cells. Bryostatin 1, another PKC activator, exerted modest cytostatic effects on MCF-7 cells while producing a cytotoxic response at low doses in MCF-7-PKC-alpha cells that waned at higher concentrations. TPA-treated MCF-7-PKC-alpha cells accumulated in G2/M, did not express p53, displayed decreased Cip1 expression, and demonstrated a reduction in retinoblastoma hypophosphorylation. TPA-treated MCF-7-PKC-alpha cells expressed gadd-45 which occurred before the onset of apoptosis. Thus, alterations in the PKC pathway can modulate the decision of a breast cancer cell to undergo death or differentiation. In addition, these data show that PKC activation can induce expression of gadd45 in a p53-independent fashion.

Incidence of acute care complications in vertebral column fracture patients with and without spinal cord injury

STUDY DESIGN

This study retrospectively analyzed vertebral column fractures in trauma patients during a 2-year period. Data from a multicenter trauma registry were used.

OBJECTIVES

The purpose of this study was to ascertain and describe the initial in-hospital morbidity and mortality rates for patients with vertebral column fractures with and without spinal cord injury.

SUMMARY OF BACKGROUND DATA

Patients with vertebral fractures and associated spinal cord injuries experience more medical complications than those without spinal cord injuries. However, the precise incidence and relative risk of complications during acute care hospitalization for these two groups are not well documented.

METHODS

Vertebral column fractures in 419 adolescent and adult trauma patients hospitalized during a 2-year period were retrospectively analyzed using data from a multicenter trauma registry.

RESULTS

Of the 419 patients, 104 (24.8%) had an associated spinal cord injury. More than half of the spinal cord injury patients (52.9%) and 20.6% of those without spinal cord injury had one or more complications during their hospitalization. Complications resulted in an average of 33.1 extra hospital days, which extrapolates nationally into 1.5 million additional days annually. The four complications differing most significantly in incidence between the spinal cord injury group and the non-spinal cord injury group were: urinary tract infections (24.0% vs. 8.6%), respiratory (23.1% vs. 8.6%), cardiac (11.5% vs. 3.2%), and decubitus ulcer (7.7% vs. 1.0%). Pneumonia, although not statistically different, was high in both groups (13.5% vs. 7.3%).

CONCLUSIONS

The incidence of the 25 types of medical complications reported here provides specific and relevant information to assist health professionals in treating patients during their acute care. We estimate that complications during initial hospitalization add $1.5 billion annually to the cost of caring for patients with vertebral fractures in the United States.

MCF-7 breast cancer cells transfected with protein kinase C-alpha exhibit altered expression of other protein kinase C isoforms and display a more aggressive neoplastic phenotype

Increased protein kinase C (PKC) activity in malignant breast tissue and positive correlations between PKC activity and expression of a more aggressive phenotype in breast cancer cell lines suggest a role for this signal transduction pathway in the pathogenesis and/or progression of breast cancer. To examine the role of PKC in the progression of breast cancer, human MCF-7 breast cancer cells were transfected with PKC-alpha, and a group of heterogenous cells stably overexpressing PKC-alpha were isolated (MCF-7-PKC-alpha). MCF-7-PKC-alpha cells expressed fivefold higher levels of PKC-alpha as compared to parental or vector-transfected MCF-7 cells. MCF-7-PKC-alpha cells also displayed a substantial increase in endogenous expression of PKC-beta and decreases in expression of the novel delta- and eta-PKC isoforms. MCF-7-PKC-alpha cells displayed an enhanced proliferative rate, anchorage-independent growth, dramatic morphologic alterations including loss of an epithelioid appearance, and increased tumorigenicity in nude mice. MCF-7-PKC-alpha cells exhibited a significant reduction in estrogen receptor expression and decreases in estrogen-dependent gene expression. These findings suggest that the PKC pathway may modulate progression of breast cancer to a more aggressive neoplastic process.

Management of multisite occupational health services. A hospital/private clinic perspective: changing trends for the 1990s

A strong regional program can be successful in either a single location or at multiple locations, but it cannot function properly if it is not well organized and staffed properly to deliver services. Extremely important elements to the success of an occupational health clinic that serves a wide geographical region are client retention, a strong information system to manage programs for multiple employers, and cutting-edge leadership that stays in the forefront and educates the business community on emerging issues in occupational health and safety.

Rainfall patterns in a major wheat-growing region of Australia

Rainfall is an important variable in the wheat production areas of Australia. This analysis examines, firstly, the pattern of rainfall over 2.3 million ha of a high-quality wheat-producing region, and secondly, develops regression equations for rainfall prediction over this region. Most of the variation in rainfall pattern across the region is accounted for by differences in October-to-March (summer) rainfall and in April-to-September (winter) rainfall. The summer rainfall differences account for over two thirds of the variation. Based on these two rainfall periods, a partitioning of the study area reveals five distinct regions. The second part of the analysis uses multiple regression to provide a set of equations for rainfall prediction at any location in the region, for a number of rainfall periods. These equations use altitude, longitude and latitude as predictors. Nearly all of the equations explain between 80% and 94% of the variation in rainfall. Differences between regions are accounted for in the analysis, making the equations widely applicable. The validity of the mean rainfall equations was tested on three further sites: the mean prediction error was 6.9%. This approach may be applicable where large land masses with similar geographical features occur.

Characteristics of frost in a major wheat-growing region of Australia

Frost at anthesis of wheat reduces grain set. Characteristics of frost in a large section of the wheat belt of one Australian state (N.S.W.) are described. Using cluster analysis, the region can be divided into four homogeneous areas according to five general characteristics of frost These characteristics are the mean Julian day of first and last frost, the mean number of frost days, the proportion of single-day frosts (days on which a frost did not occur on the following day) from August to October and the proportion of frost free periods from August to October of less than 5 days' duration. All these characteristics were found to,be closely related to altitude in all areas, but not to latitude or longitude. Within each area, regression equations were developed which explained at least 87% of the variation in four of the general characteristics. Thus, altitude appears to be a useful predictor for these characteristics. The validity of each equation was tested using three independent data sets. The mean percentage errors for the mean Julian day of first and last frost and the proportion of single-day frosts from August to October were 5, 5 and 8% respectively. Errors for the mean number of frost days and proportion of frost free periods from August to October of less than 5 days duration were approximately 7% for one site and approximately 20% for two other sites. The characteristics of frost in the period in which most winter crops flower are also described. The characteristics are the mean date of last heavy frost and last frost, and frost spells in each of August, September and October. In order to minimize risk from frost during anthesis and from high temperature and water stress during grain filling, this analysis suggests that anthesis should occur in early/mid September, late September/early October and early/mid October for the western, central and eastern parts of the region respectively. For areas in the north-eastern and south-eastern parts that are above 500 m, anthesis should occur mid/late October and early/mid November respectively. These analytical findings are consistent with field studies on wheat. A weak negative correlation between the first and the last frost is present in most of the sites of the region. This suggests that if in any particular year the first frost occurs earlier than its long-term mean, then the last frost tends to occur later than its long-term mean.

Age-dependent expression of protein kinase C isoforms in rat islets

The appearance of the biphasic insulin secretory response several days after birth suggests that maturation of a critical step in stimulus-secretion coupling occurs during the early neonatal period. To clarify the role of protein kinase C (PKC) during this time, we examined the pancreatic islets of adult, 3-day neonatal, and 19-day fetal rats for the presence of different PKC isoenzymes. Western-blot analysis of islet extracts showed the presence of PKC isoforms in both adult and neonatal tissues. Immunocytochemistry of adult islets revealed a differential expression in islet cell types. PKC-alpha was found only in beta-cells, PKC-gamma in alpha-cells, and PKC-epsilon in delta-cells and vascular walls. Immunoreactivity for PKC-beta was not detected in any cell type. All three isoenzymes were also present in neonatal islets; however, in contrast to adult tissue, immunoreactivity for either PKC-alpha or PKC-gamma was present in relatively few cells. There was no apparent immunoreactivity for PKC-alpha or PKC-gamma in fetal islets, although these tissues contained strong staining for insulin and glucagon. These data show that three of the PKC isoforms are restricted to a particular islet cell type, where they may play a unique role in the secretion of a specific hormone. Moreover, our results demonstrate that these enzymes, especially PKC-alpha, appear during the early neonatal period. This age-dependent expression may be linked to the development of the biphasic insulin release response.

Factorial designs for crossover clinical trials

When measuring the joint effect of two factors it is advantageous to use a factorial design. If the application is suitable, efficiency may be further improved by using a crossover design. This paper presents a flexible method for amalgamating these two devices. Designs are constructed from smaller designs, known as bricks, generated cyclically from tabulated initial sequences. The bricks have known efficiencies for estimation of direct treatment main effects and interactions; the efficiencies can be simply combined to approximate the efficiencies of the whole design. This allows the user to build a design that is tailored to the particular objectives of the experiment. Three and four periods, and two factors with up to four levels are considered.

Effects of combined secretagogues and extracellular calcium on neonatal insulin release

The insulin response of 3-day old neonatal rat islets was evaluated following a 1 h incubation with glucose alone and in the presence of 30 nM sulfated cholecystokinin octapeptide (CCK) and/or 20 microM carbachol (CCh). Insulin secretion was found to be incrementally increased from the lowest glucose concentration and enhanced several fold in the presence of CCK and/or CCh. In combination, CCK and CCh increased glucose-stimulated insulin secretion by an amount equivalent to the sum of their individual increases. The presence of either CCK alone or CCK plus CCh increased phosphoinositide hydrolysis by the same relative amount that they increased insulin secretion when compared to 8.3 mM glucose. Glucose-stimulated insulin secretion was totally inhibited when calcium was omitted from the incubation buffer; this effect was partially negated by CCK alone and more so by CCK combined with CCh. Insulin secretion in response to 8.3 mM glucose alone was unchanged when calcium in the incubation buffer was increased from 1 to 5 mM; however, the insulin response to 16.7 mM glucose alone and 8.3 mM glucose in the presence of CCK and/or CCh was increased under this condition. Thus, we have shown that, even at 3 days postpartum, insulin secretion from isolated islets is a complex response capable of being molded by several secretagogues at once and ultimately determined by interplay of different signaling systems activated.

Age-dependent stimulation of neonatal insulin release and inositol phosphate accumulation by CCK-8 and carbachol

Development of a robust insulin secretory response to glucose occurs during the early neonatal period. To determine if neuroendocrine agents play a role during this time, we studied the effects of selected peptides and neurotransmitters on insulin release and polyphosphoinositide metabolism in islets isolated from 1- and 3-day neonatal rats. Vasoactive intestinal peptide had no effect on glucose-stimulated release in either islet population. In contrast, sulfated cholecystokinin octapeptide (CCK-8) significantly enhanced glucose-induced insulin release in both islet groups. One-day islets were stimulated only by a concentration of 300 nM, whereas 3-day islets were responsive at 3 nM. Similar to CCK-8, there were clear differences in responses to carbachol between 1- and 3-day islets. One-day islets required a concentration of 200 microM for insulin release to be significantly greater than with glucose alone; 3-day islet insulin release was significant at 2 microM carbachol. Both agonists stimulated inositol phosphate accumulation in 3-day islets, but only CCK-8 caused a significant increase over glucose-induced levels in 1-day islets. These results indicate that islet responsiveness to CCK-8 and carbachol develops in parallel during the early neonatal period. This development may be linked to the maturation of a critical step of stimulus-secretion coupling through which these agents act.

Effects of cholecystokinin octapeptide and carbachol on neonatal insulin secretory dynamics

The effects of glucose, sulfated cholecystokinin-octapeptide (CCK-8), or carbachol on insulin secretory dynamics were studied in pancreatic islets isolated from 1- and 3-day-old neonatal rats. When challenged with glucose, 1-day islets responded with a definite first phase and elevated secretion during the latter part of the stimulation period; 3-day islets had a first phase and a rising, sustained second phase. The presence of stimulatory concentrations of CCK-8 or carbachol in addition to glucose caused dramatic changes in the release pattern in both islet populations. In 1-day islets, carbachol stimulated mainly first phase secretion whereas CCK-8 enhanced first phase release and produced a definite second phase response. The two secretagogues increased significantly both phases of release in 3-day islets with no differences between the two agents in their effects. These results indicate that CCK-8 and carbachol differentially stimulate neonatal insulin secretion, possibly through different steps in the stimulus-secretion pathway. They also suggest that the cellular mechanism for second phase release is present in 1-day islets and can be activated by CCK-8.

Regulation of insulin and interleukin-1 release after Propionibacterium acnes-induced macrophage activation in mice

The administration of a potent activator of macrophages (M phi), Propionibacterium acnes, in nondiabetic mice was associated with the release of significant amounts of interleukin-1 (IL-1) in the peritoneal cavity and plasma within 4 hours after treatment. Shortly before IL-1 peaks were observed, the levels of pancreatic insulin, [3H]leucine-proinsulin, and insulin/total protein ratio were elevated, and followed by a transient but marked hyperinsulinemia at 4 hours after treatment. A single dose of recombinant murine IL-1 in mice was also associated with a 2- to 9-fold increase in the levels of insulin in the pancreas and plasma at 4 hours after treatment. During the period of observation after the administration of P. acnes, plasma glucose levels in treated mice were significantly less than in parallel controls. Mild hypoglycemia was observed at 7 to 10 days posttreatment. Although circulating IL-1-like activity could not be detected in plasma 1 to 10 days after P. acnes treatment, this activity was measured in activated peritoneal and liver M phi. IL-1-like activity (specific activity: 276 units/mg protein) was detected in plasma, after it was chromatographed on a Sephadex G-150 column to remove proteins with higher molecular weight. Peritoneal and liver M phi from P. acnes mice were also able to elaborate significant amounts of IL-1-like activity in their supernatants with or without Escherichia coli lipopolysaccharide. At the same time, total protein synthesis and insulin content in the pancreas in P. acnes mice were significantly lower than the parallel control (p less than 0.01). These results suggest that P. acnes-induced M phi activation in mice was associated with the modulation of insulin release and glucose homeostasis which may be attributed to the accumulation and release of IL-1 by activated M phi.

Stimulation of breathing movements by L-5-hydroxytryptophan in fetal sheep during normoxia and hypoxia

1. In fetal lambs in late gestation, systemic infusion of L-5-hydroxytryptophan (L-5-HTP) during normoxia greatly increases the incidence of fetal breathing movements (FBM) and high-voltage electrocortical activity (HV ECoG). It also induces FBM during HV ECoG and increases blood pressure. To investigate its mechanism of action, L-5-HTP was administered in conjunction with the 5-hydroxy-tryptamine (5-HT) antagonists ketanserin or cyproheptadine. L-5-HTP was also infused with or without the antagonists during hypoxia, to test whether it would overcome the inhibition of FBM by hypoxia. 2. When L-5-HTP was given in normoxia, cyproheptadine blocked and ketanserin reduced the increase in blood pressure, both drugs blocked the stimulation of FBM, but neither drug prevented the induction of prolonged episodes of HV ECoG. 3. In hypoxia, L-5-HTP similarly stimulated FBM. This effect was also blocked by cyproheptadine and was delayed by ketanserin. 4. The antagonism of the effects of L-5-HTP on blood pressure and the incidence of FBM in normoxia and hypoxia is consistent with the action of L-5-HTP via 5-HT receptors. At present there is no clear explanation of the mechanism by which L-5-HTP induces HV ECoG.

Vasoactive intestinal polypeptide enhances hormone content and insulin release in cultured fetal rat islets

The effect of porcine vasoactive intestinal polypeptide (VIP) on development of the biphasic insulin release response in cultured fetal rat islets was investigated. Fetal islets, 21.5 days gestational age, were cultured for 7 days in RPMI 1640 culture medium containing either 2.8 or 11.1 mM glucose adn subsequently challenged with 16.7 mM glucose in a perfusion system. Islets were exposed to VIP at a final concentration of 13.2 nM by adding the peptide to the perifusion buffer (acute exposure) or by adding it to the culture medium throughout the culture period (chronic exposure). Islet hormone and DNA contents were also quantitated at the end of the culture period. Acute exposure to VIP resulted in no alterations of the insulin release pattern after culture in the presence of either glucose concentration. However, chronic treatment of islets with 13.2 nM VIP in the presence of 2.8 mM glucose resulted in significant increases in the maximum rate of insulin release during the first phase and the total amount of insulin release during both phases. Similarly, islets cultured in the presence of 11.1 mM glucose and 13.2 nM VIP demonstrated enhanced biphasic insulin release patterns with increased maximum rate and total amount of release during both phases. The presence of VIP and 2.8 mM glucose increased islet glucagon and somatostatin contents, but islet DNA and insulin contents remained unchanged. These findings indicate that VIP plays a significant role in the in vitro development of the biphasic insulin release pattern and may be a factor controlling the maturation of the fetal islet in vivo.

Health promotion for children. Key to a lifetime of health

Evidence indicates that preventive healthcare in childhood reduces healthcare costs and enhances health. Physicians can assume a leadership role in promoting children's health by incorporating health promotion measures into their everyday practice, serving as resource persons or leaders in community and school efforts in health promotion, and lobbying for legislation aimed at preventive care. The goals of these efforts are to achieve a healthy childhood, provide a foundation for a healthy adulthood, and develop in children positive values about personal health responsibility and use of healthcare services.

Down-regulation of insulin receptors in Propionibacterium acnes-activated macrophages in the mouse

Intraperitoneal administration of Propionibacterium acnes in CD-1 mice was associated with the reduction in number of insulin receptors in peritoneal macrophages (M phi), and with elevated levels of insulin in plasma and the peritoneal cavity. When insulin levels returned to normal, insulin receptors in P. acnes-M phi were still reduced. Insulin appears to contribute significantly to the down-regulation of the M phi-insulin receptors during the early stage of activation. Other biologically active substances released during M phi activation might assume greater influence on insulin resistance in activated M phi at a later stage. The induction of transient hyperinsulinemia in P. acnes-treated mice might be attributed to the effect of concurrently elevated interleukin-1 (IL-1) released in the early course of M phi activation.

Health-risk appraisal. Helping patients predict and prevent health problems

Health-risk appraisals (HRAs) are self-scored questionnaires or computer programs that use demographic and risk-factor data to estimate the most likely causes of death and to provide guidance on how to reduce risk of death. The clinical usefulness of HRAs lies in their ability to motivate patients to modify negative habits and lifestyles. Still very much in a developmental stage, HRAs are not substitutes for preventive health examinations and are best used in conjunction with ongoing physician-supervised health-promotion and disease-prevention efforts.

Coping with insomnia. Helping patients manage sleeplessness without drugs

Sleep, a vital ingredient in life, is often taken for granted until something goes awry and sleep no longer comes easily. Occasional bouts of sleeplessness are normal, but for some persons, perhaps as much as 20% of the adult population, insomnia is a recurring problem for which they may turn to over-the-counter or prescription sleeping pills as a solution. In all but the most extreme cases, however, medication is not necessary and nondrug remedies are sufficient for lulling the patient back to sleep. In this article, Dr Fletcher describes what everyone should know about the complex process of sleep and offers suggestions, including some familiar old-fashioned home remedies, on what to do when sleep is evasive.

The effects of vagotomy on compensatory ovarian hypertrophy and follicular activation after unilateral ovariectomy

Following unilateral ovariectomy in the rat, the remaining ovary undergoes rapid compensatory changes including an increase in the number of antral follicles (follicular activation) and an increase in ovarian weight (compensatory ovarian hypertrophy). The ovary is innervated by the vagus nerve (Burden et al., 1983). In the present study, the effects of right and left cervical vagotomy and abdominal vagotomy on follicular activation and compensatory ovarian hypertrophy in the remaining right or left ovary were compared 15 days after unilateral ovariectomy. Neither right nor left cervical vagotomy affected compensatory ovarian hypertrophy of the right or left ovaries but abdominal vagotomy depressed compensatory ovarian hypertrophy in both the right and left ovaries. Left cervical vagotomy did not inhibit follicular activation, but right cervical vagotomy prevented follicular activation in the right but not left ovary. Also, abdominal vagotomy inhibited follicular activation in the right but not the left ovary. In animals with both ovaries which were subjected to the left or right cervical vagotomy or abdominal vagotomy follicular counts in both right and left ovaries were similar. Collectively, these data indicate that the vagus nerve participates in follicular activation after unilateral ovariectomy. The data also indicate that the right ovary is more dependent on vagal influences for follicular activation than the left ovary.

Diet and coronary heart disease. Helping patients reduce serum cholesterol level

Although coronary heart disease (CHD) remains the No. 1 cause of death in the United States, the CHD mortality rate has shown a recent decline. This has been attributed to lower fat consumption in the general population, with associated lower serum cholesterol levels. Thus, diet seems to be an important factor in controlling cholesterol level. Acting on this hypothesis, primary care physicians can help patients make appropriate dietary changes. We believe that persons at risk of hypercholesterolemia need to be identified in adolescence by measurement of total serum cholesterol level and that testing should be done every two years after age 25. The American Heart Association's prudent diet is recommended for all patients, especially those with a serum cholesterol level above 240 mg/dl. When dietary restriction does not bring the level within this limit, use of cholesterol-lowering agents is considered. To be lasting, dietary change must be gradual; realistic immediate and long-term goals should be established. In addition, the diet must be nutritionally sound and the patient must receive support from family members.

An immunocytochemical study of the pancreatic islet system of the channel catfish

The endocrine pancreas of the channel catfish is segregated into a large primary islet and numerous smaller secondary islets. In view of cell distribution differences in mammalian islets of ventral and dorsal primordia, we have determined the percentage volumes of insulin-, glucagon-, and somatostatin-containing cells in primary and secondary catfish islets to ascertain if these islets correlated with those derived from ventral and dorsal primordia in mammals. Islets were immunocytochemically stained using antisera to anglerfish insulin, porcine glucagon, and synthetic somatostatin and volume densities were quantified on light micrographs by point-counting procedures. In both primary and secondary islets the insulin-, glucagon-, and somatostatin-containing cells comprised approximately 32%, 23%, and 38% of the endocrine cell volumes, respectively. Therefore, the cell populations did not reflect any embryological differences between the two groups of islets. In this study, the volume densities of insulin-reactive cells in the primary islet were less than previously reported, and the overall insulin staining was about one-half of that seen in mammals. The volume density of somatostatin-reactive cells in primary islets was greater than previously reported. Based on these data, primary and secondary islets of the catfish do not appear to have a similar development to the ventral and dorsal islets of the mammalian system.

Abnormal islet and adipocyte function in young B-cell-deficient rats with near-normoglycemia

Sprague-Dawley male rats were injected at 2 days of age with streptozotocin (SZ). At 4 wk of age the fed plasma glucose concentration of the SZ group was 151 +/- 6 mg/dl as compared with 133 +/- 4 for the control group. The fed plasma insulin values were indistinguishable, however. In response to an intraperitoneal glucose challenge the SZ group had marked glucose intolerance and virtually no rise in plasma insulin. After a meal challenge the SZ group also had glucose intolerance, but plasma insulin responses were similar to those of the control. The pancreata of the 4-wk-old rats were perfused in vitro and the SZ group had essentially no response to glucose, but did respond to arginine. Adipocytes of the 4-wk-old SZ rats had impaired glucose conversion to CO2 similar to that seen in the more hyperglycemic 6-wk-old SZ rats. Castration carried out at about 3 wk of age did not influence the hyperglycemia seen at 6 wk of age and later. These data indicate that 4-wk-old SZ rats, while having near-normal plasma glucose levels and normal plasma insulin values, have clearly abnormal B-cell and adipocyte function. With increasing age and weight gain these SZ rats develop frank hyperglycemia.

Hormone release by islet B cell-enriched and A and D cell-enriched populations prepared by flow cytometry

Dispersed pancreatic islet cells were analyzed for their low forward angle light scatter using flow cytometry. The cells produced a distinct light scatter pattern which appeared to be a function of cell size and not cell granularity. RIA of hormone content of cells collected from different regions of the pattern revealed that glucagon- and somatostatin-containing cells were concentrated in regions of lower scatter intensity and that insulin-containing cells were more numerous in regions of higher intensity. Relative to the original cell suspension, these preparations were enriched 3-fold in glucagon and somatostatin content and 6-fold in insulin content. The function of intact islets, unsorted dispersed cells, and sorted dispersed cells was examined before and after 4 days of culture. Before culture, all of the dispersed cell populations had elevated basal secretion compared with intact islets and did not respond to stimulatory concentrations of glucose, arginine, or 3-isobutyl-1-methylxanthine. After culture for 4 days, basal secretion fell, and responsiveness returned. In both the A/D cell-enriched and the B cell-enriched cultured populations, the percentage of single cells was approximately 95%. The insulin release patterns from these populations were similar to those from intact islets and unsorted dispersed cells. Glucagon release from all of the dispersed cell populations far exceeded that from intact islets. This study suggests that the structural organization of islets influences A cell function, but a clear influence upon B cell function has not been demonstrated.