Evaluation of sources cited by an exotic animal formulary for supporting drug dosages and reference intervals in mammals

OBJECTIVES

Formularies are intended to simplify clinical decision-making by collecting evidence-based information on drugs and their dosages. This study assessed the characteristics of sources used to support drug dosages and reference intervals for mammals in a specific exotic animal formulary, and how the sources had changed over five editions.

METHODS

Each reference supporting drug dosages and reference intervals in the sections for ferrets, rabbits, rodents, hedgehogs and miniature pigs in all five editions of the formulary was evaluated and classified by two independent investigators in terms of the type of source cited. Univariable and multi-variable logistic regression models were built to evaluate changes between editions and sections.

RESULTS

In total, 1338 references supporting drug dosages and 180 references supporting reference intervals were included from all editions of the formulary. Primary sources were cited by 525 (39.2%) and 39 (21.7%) of the drug and reference interval references, respectively. For drug dosages, the current edition of the formulary (2018) cited a higher proportion of primary rather than secondary sources compared with the first edition (odds ratios 3.4, 95% confidence interval 2.1 to 5.6), while for reference intervals there were no significant changes between editions. In the current edition of the formulary, the 168 secondary sources cited for drug dosages included 78 (46.4%) textbooks, 63 (37.5%) reviews, 14 (8.3%) personal communications and 7 (4.2%) other formularies.

CLINICAL SIGNIFICANCE

A large proportion of references supporting drug dosages and reference intervals in the evaluated sections cited secondary sources. Although modest improvements have been observed over time, practitioners should be aware that the evidence supporting several drugs and dosages was limited, and assess the information within the formulary critically.

Pharmacokinetics, excretion, and mass balance of 14C after administration of 14C-cholesterol-labeled AmBisome to healthy volunteers

Amphotericin B (AmB) in small unilamellar liposomes (AmBisome) provides higher plasma concentrations and greater safety than the conventional deoxycholate formulation. The authors compared the disposition of the liposome's drug and cholesterol components by measuring AmB and radioactivity in plasma, urine, and feces for 1 week after a single 2-hour infusion of 14C-cholesterol-labeled AmBisome (2 mg/kg, 1 microgCi/kg) in healthy adults (4 males, 1 female). The plasma profile of 14C-cholesterol differed from that of AmB, lacking an initial rapid disappearance phase, having a lower total clearance, and having a volume of distribution (0.13 L/kg) close to that of the plasma compartment. The biphasic disappearance and long plasma half-life (147 h) of 14C-cholesterol were similar to those of other low-clearance liposomes. This and the low clearance of 14C-cholesterol from the plasma compartment suggest that it served as a liposome marker. The plasma drug-lipid ratio fell during the study, showing that AmB was cleared from plasma more rapidly than cholesterol or liposomes and suggesting that the composition of the liposomes changed over time. 14C-radioactivity was recovered mainly in the feces (9.5% of dose), consistent with the catabolism of cholesterol to bile salts. Combined fecal and renal clearances were < 18% of total clearance, suggesting that most of the liposomal drug and lipid remained in the body 1 week after dosing. Thus, AmBisome remains in the circulation for an extended period of time while releasing AmB, resulting in its markedly altered pharmacokinetic and safety profiles.

Complications of mandibular fractures

Timely repair of mandibular fractures remains an effective means to reduce pain, restore function, and prevent complications. This study addresses the effect of the time interval between injury and treatment on the overall complication rate, the complication rate between various treatment modalities (mandibular-maxillary fixation [MMF] alone, MMF with intraosseous wire bone fixation, and MMF with rigid internal fixation), and the relationship of inpatient vs. outpatient management. Cost was also examined with respect to choice of management. We report a retrospective series of 308 consecutive patients managed at the University of Miami/Jackson Memorial Hospital. Patients who received treatment 3 to 10 days following injury were found to have a lower complication rate than earlier or later repair. We postulate that most patients with mandibular fractures may be managed on an outpatient basis, which represents a considerable savings in cost.

Assessing and overcoming situational obstacles to dietary adherence in adolescents with IDDM

PURPOSE

To develop and evaluate a tool for assessing selected aspects of dietary adherence in adolescents with diabetes mellitus (IDDM).

METHODS

The Situational Obstacles to Dietary Adherence Questionnaire (SODA) is a 30-item inventory that yields a total self-efficacy score and scales that measure cognitive and behavioral coping strategies. Alternative forms of the SODA were administered at the beginning and end of a summer camp for youngsters with IDDM in order to obtain evidence for its reliability and validity, and to evaluate the impact of an educational intervention. The program consisted of two 50-minute small group sessions intended to help adolescents with IDDM improve their ability to cope with challenging dietary situations. Using the method of anchored instruction, the campers first viewed a video about a teenager with diabetes who faces common situations that make diabetes self-management difficult. Group problem-solving sessions led by a registered dietitian were used to help campers learn more effective ways to solve dietary problems.

RESULTS AND CONCLUSIONS

Results suggested that the SODA has reasonable reliability and validity. In addition, anchored instruction improved dietary self-efficacy and changed young adolescents' estimates of how often they would use selected cognitive and behavioral strategies to solve dietary problems.

Limited toxicity of prolonged therapy with high doses of amphotericin B lipid complex

We describe six patients with invasive fungal infections who received large cumulative doses (22.3-73.6 g) of amphotericin B lipid complex (ABLC) over 21-121 weeks. The drug was well tolerated at these very large doses, and there was limited toxicity. Collectively, these patients received ABLC therapy for a mean of 53.8 weeks (range, 21-121 weeks). The mean serum creatinine level at the start of ABLC therapy was 1 mg/dL (range, 0.4-1.9 mg/dL), and at the end of therapy this level was 1.5 mg/dL (range, 1.0-2.0 mg/dL). Over the course of therapy, only two patients had serum creatinine levels of > or = 2 mg/dL, with transient peak serum creatinine levels of 3.5 and 2.8 mg/dL, respectively. Several patients required replacement therapy with oral or intravenous potassium. None of the patients had ABLC-associated toxic effects necessitating discontinuation of the treatment. ABLC may be given in substantially larger doses than conventional amphotericin B, and very high doses of ABLC that are administered over several months appear to be relatively less toxic than those of conventional amphotericin B.

Evaluation of a possible association of urban air toxics and asthma

The prevalence of asthma, measured either as the frequency of hospital admissions or number of deaths attributed to asthma, has increased over the last 15 to 20 years. Rapid increases in disease prevalence are more likely to be attributable to environmental than genetic factors. Inferring from past associations between air pollution and asthma, it is feasible that changes in the ambient environment could contribute to this increase in morbidity and mortality. Scientific evaluation of the links between air pollution and the exacerbation of asthma is incomplete, however. Currently, criteria pollutants [SOx, NOx, O3, CO, Pb, particulate matter (PM10)] and other risk factors (exposure to environmental tobacco smoke, volatile organic compounds, etc.) are constantly being evaluated as to their possible contributions to this situation. Data from these studies suggest that increases in respiratory disease are associated with exposures to ambient concentrations of particulate and gaseous pollutants. Similarly, exposure to environmental tobacco smoke, also a mixture of particulate and gaseous air toxics, has been associated with an increase in asthma among children. In addition, current associations of adverse health effects with existing pollution measurements are often noted at concentrations below those that produce effects in controlled animal and human exposures to each pollutant alone. These findings imply that adverse responses are augmented when persons are exposed to irritant mixtures of particles and gases and that current measurements of air pollution are, in part, indirect in that the concentrations of criteria pollutants are acting as surrogates of our exposure to a complex mixture. Other irritant air pollutants, including certain urban air toxics, are associated with asthma in occupational settings and may interact with criteria pollutants in ambient air to exacerbate asthma. An evaluation of dose-response information for urban air toxics and biological feasibility as possible contributors to asthma is therefore needed. However, this evaluation is compounded by a lack of information on the concentrations of these compounds in the ambient air and their effects on asthma morbidity and mortality. Through an initial review of the current toxicological literature, we propose a tentative list of 30 compounds that could have the highest impact on asthma and respiratory health. These compounds were selected based on their ability to induce or exacerbate asthma in occupational and nonoccupational settings, their allergic potential and ability to react with biological macromolecules, and lastly, their ability to irritate the respiratory passages. We recommend better documentation of exposure to these compounds through routine air sampling and evaluation of total exposure and further evaluation of biological mechanisms through laboratory and epidemiological studies directed specifically at the role these substances play in the induction and exacerbation of asthma.

Serum CD4, CD8, and interleukin-2 receptor levels in childhood acute myeloid leukemia

Leukemic cell expression and serum levels of CD4, CD8, and interleukin-2 receptor (IL-2R) were determined at diagnosis for children or adolescents with acute myeloid leukemia (AML). Cellular expression of CD4 was detected in 18 of 62 cases, CD8 in none of 60 cases, and IL-2R in one of 33 cases tested. Myeloblasts of the M4 and M5 subtypes expressed CD4 significantly more frequently than other FAB subtypes (p = 0.0001). Serum levels of the three soluble factors (tested for 91 patients) were positively correlated with each other. Increased serum CD4 levels were significantly associated with cellular CD4 expression, high leukocyte count, M5 leukemia, spleen enlargement, and age less than 1 year. High serum CD8 levels correlated significantly with splenomegaly, extramedullary disease, absence of Auer rods, and high leukocyte count. Cases with high serum IL-2R levels were less likely to have Auer rods and more likely to have splenomegaly and M5 leukemia; serum levels greater than 750 U/ml were associated with a higher probability of treatment failure (p = 0.05), even after adjustment for other potential prognostic factors. Further studies of serum CD4, CD8, and IL-2R levels may help to clarify the immunoregulatory role of T-cells in patients with AML.

Reactivation of Toxoplasma gondii by cytomegalovirus disease in mice: antimicrobial activities of macrophages

Reactivation of Toxoplasma gondii infection often occurs concurrently with active cytomegalovirus (CMV) disease in immunocompromised patients, and CMV disease results in immunosuppression. To determine if murine CMV (MCMV) infection decreases resistance to T. gondii, mice with latent T. gondii infection were infected with MCMV. T. gondii infection reactivated, manifested primarily as pneumonia. Lung macrophages supported the growth of T. gondii before, during, and after T. gondii reactivation. Peritoneal macrophages inhibited the growth of T. gondii as pneumonia developed and became permissive as pneumonia resolved. Mice with latent T. gondii infection could survive larger doses of MCMV than could controls. Thus, MCMV infection led to reactivation of latent T. gondii infection in mice. Activation of lung macrophages, assessed by their ability to inhibit replication of T. gondii in vitro, was not associated with control of T. gondii infection.

Group A beta-hemolytic streptococcal skin infections in a US meat-packing plant

In 1985, the second reported outbreak of group A beta-hemolytic streptococcal (GABHS) skin infections among US meat packers was recognized at an Oregon meat-packing plant. All 69 plant workers were interviewed and examined for the presence of pustular, draining, or inflamed lesions. During a three-month period, 44 episodes of skin infection occurred in 32 workers, all but four of whom worked in boning or killing areas. Acquiring infection was associated with job category (relative risk [RR], 5.7; 95% confidence intervals [CI], 2.9 to 11.3) and having at least two hand lacerations (RR adjusted for occupation, 6.2; 95% CI, 3.0 to 12.5). Group A beta-hemolytic Streptococcus (18), Staphylococcus aureus (12), or both (20) were isolated from 70 lesions cultured. Meat is suspected as a vehicle of transmission because cultures of two meat specimens contained the same GABHS strain as did 24 isolates from patients. Increasing reports of GABHS skin infections in meat packers suggest that this occupational risk may be more common than is realized.

Ventral tegmental area of the rabbit brain: a developmental Golgi study

The ventral tegmental area (VTA) of the rabbit mesencephalon was examined with Golgi-Cox impregnation at neonatal (days 3-21 of age) and young adult (6-12 months of age) stages of development. Neurons in the dorsal midline were small, with sparsely-branched, vertically-oriented dendrites. Neurons in the ventral midline were medium-sized, oval cells with sparse, vertically-oriented dendrites, and multipolar cells with more abundant diffusely-oriented dendrites. Neurons in the medial zone of the VTA, between the midline and the exiting III nerve fibers, were oval in shape, medium in size, and possessed vertical dendritic arborizations of greater size and extent of branching than those in the dorsal midline. Lateral neurons, found among III nerve fibers, were medium-sized and possessed dendritic trees that were specifically oriented in a vertical or horizontal plane, or were diffusely-branched with more abundant arborizations than their specifically oriented counterpart. Very small neurons with short, single branches were scattered among all regions of the VTA. The major cell types showed a similar pattern of dendritic maturation. At 3-9 days of age, the dendrites were generally short, spiny and poorly branched. From days 9-21, the branches increased in number and length, spines were lost, and these neurons rapidly approached adult size and form. The neurons of VTA appear isodendritic in form, and developed in a pattern consistent with other areas of reticular formation, suggesting that VTA may be part of the reticular core of the brain stem.(ABSTRACT TRUNCATED AT 250 WORDS)

Arresting development arrests aging in the nematode Caenorhabditis elegans

Larval development of the nematode, Caenorhabditis elegans, can be arrested by either of two different treatment: (1) complete starvation, or (2) growth in a partially defined culture medium (axenic medium) of strains adapted to bacterial growth. The developmental arrest is complete under total starvation and the starved populations live about 10 days. The developmental block is incomplete in axenic medium; most animals mature but maturation takes 10 times longer than normal. If developmentally arrested cultures are returned to growth on E. coli, both the completely starved and the axenically arrested cultures mature at normal rates. Life-span is prolonged by 1 day for each day of complete starvation; life-span is prolonged by 0.7 days for each day of axenic arrest. These results suggest that aging and development are closely coupled in this system. The results are discussed in terms of previous observations on nutritional deprivation in other invertebrates and caloric restriction in mammals and are interpreted in light of theoretical models of senescence.

Left ventricular dysfunction--bedside Valsalva manoeuvre

Thirty-seven patients were evaluated before cardiac catheterisation by bedside physical examination, including Valsalva manoeuvre, to assess the value of the sphygmomanometrically determined arterial pressure responses during the Valsalva manoeuvre and to compare its sensitivity, specificity, and predictive accuracy in the detection of left ventricular dysfunction with that of the commonly used diagnostic signs including the chest x-ray. Patients not on beta-blockade treatment could be separated into three distinct arterial pressure responses detectable at the bedside which corresponded well to three statistically different groups with regard to left ventricular ejection fraction (0.29 +/0 0.11, 0.48 +/0 0.15, 0.69 +/0 0.11) and left ventricular end-diastolic pressure (38 +/- 5 mmHg, 24 +/- 10 mmHg, 14 +/- 5 mmHg) at subsequent cardiac catheterisation. In patients not on beta-blockade it was shown for the first time that (1) the height of the systolic arterial pressure overshoot was directly related to left ventricular ejection fraction and inversely related to left ventricular end-diastolic pressure, and that (2) the bedside sphygmomanometrically determined arterial pressure response during Valsalva manoeuvre provided a semiquantitative estimate of left ventricular function and was unsurpassed in its ability to do so by any of the standard diagnostic signs including the chest x-ray film.

The effect of long-distance running on plasma immunoreactive glucagon levels

Twelve highly conditioned long-distance runners were studied to determine the effects of marathon (42 km) and 10,000 m running on plasma immunoreactive glucagon (IRG), serum immunoreactive insulin (IRI), and serum glucose (G) levels. Blood samples were drawn just prior to and immediately upon completion of the run. Marathon running resulted in no significant change in G, IRI, or IRG levels. After running 10,000 m, plasma IRG levels did not change significantly, while IRI and G increased significantly. In evaluating the pooled data from both runs, a significant inverse correlation was observed between delta G and delta IRG. This relationship between delta G and delta IRG suggests that glucagon plays a role in maintaining normal blood glucose levels during strenuous exercise.

II. A method of reporting formulation

The authors present a method of reporting and evaluating a formulation. The reporting of a formulation includes a summary introduction, biological considerations, psychosocial considerations and hypothesis construction. Three sample formulations are scrutinized and specific critical evaluations offered. The subsequent reformulations are presented.

I. Formulation

The authors describe a systematic approach to the process of formulation. Four interlocking phases are considered. The longitudinal data collection evaluate the patient's developmental journey. The cross-sectional evaluation includes careful consideration of phenomenological and dynamic factors. The integrative evaluation of these factors permits the construction of both a dynamic and a phenomenological diagnosis. Finally, in hypothesizing a tentative prognosis, we attemt to predict the capacity and quality of a person's potential change and readjustment.

Lactate metabolism after aorto-coronary artery vein bypass grafts

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