Elevating dairy research and extension through partnership: Outcomes from the United States Department of Agriculture and National Dairy Council collaborative meeting to develop a coordination roadmap

Dairy foods provide a significant portion of the recommended daily nutrition for much of the US population. Improving the availability of safe and nutritious dairy products and decreasing the environmental impact of the dairy community continue to be high priorities for both industry and the public sector. In recognition of these shared priorities, scientists and other specialists from the USDA, National Dairy Council, industry, academia, and nongovernmental organizations participated in the "Elevating Dairy Research and Extension Through Partnership" meeting on June 19, 2018. The purpose of the meeting was to strengthen partnerships and identify dairy-related research and extension needs in human nutrition, environmental sustainability, food safety, and product innovation that would benefit from enhanced coordination and collaboration across the dairy community, academia, and government. To catalyze further progress on these topics, the meeting organizers agreed to leverage the content and expertise that emerged from the meeting to develop a dairy research and extension coordination roadmap. The roadmap will establish and articulate a vision for coordinated collaboration between USDA researchers, the National Dairy Council, university researchers, extension specialists, and other dairy community stakeholders in the private and public sectors. This article represents the proceedings of the meeting and is intended to broadly communicate the dairy research and extension discussion and next steps to the dairy research and extension communities and other stakeholders in industry, academic, and government sectors.

The influence of diet upon liver function tests and serum lipids in healthy male volunteers resident in a Phase I unit

AIM

To investigate the effect of diet upon liver function tests and serum lipids within the restricted environment of a Phase I unit.

METHODS

An open randomized three-way crossover study was designed with subjects consuming three types of diet. The diets comprised, a balanced normal calorie diet, a high-carbohydrate high-calorie diet and a high-fat high-calorie diet. Each diet was consumed in a randomized sequence over 8 days with a recovery period of 14 days between periods. The blood concentrations of various laboratory parameters were measured at intervals throughout each dietary period and during the recovery periods.

RESULTS

Blood transaminase activity and triglyceride concentrations increased significantly whilst subjects consumed a high-carbohydrate high-calorie diet but not when fed either a high-fat high-calorie diet or a balanced normal calorie diet.

CONCLUSIONS

The rises in transaminases and triglycerides were caused by the carbohydrate content of the diet rather than its calorific value. Sucrose rather than starch was the carbohydrate which caused the rise in transaminases and triglycerides. The importance of controlling diet in Phase I studies is stressed.

Early microdose drug studies in human volunteers can minimise animal testing: Proceedings of a workshop organised by Volunteers in Research and Testing

Testing the safety and efficacy of a successful human medicine involves many laboratory animals, which can sometimes be subjected to considerable suffering and distress. Also, it is necessary to extrapolate from the test species to humans. UK and European legislation requires that Replacement, Reduction and Refinement of animal procedures (the Three Rs) are implemented wherever possible. Over the last decade, there has been substantial progress with applying in vitro and in silico methods to both drug efficacy and safety testing. This paper is a report of the discussions and recommendations arising from a workshop on the role that might be played by human volunteer studies in the very early stages of drug development. The workshop was organised in November, 2001 by Volunteers in Research and Testing, a group of individuals in the UK which launched an initiative in 1994 to identify where and how human volunteers can participate safely in biomedical studies to replace laboratory animals. It was considered that conducting pre-Phase I very low dose human studies (sub-toxic and below the dose threshold for measurable pharmacological or clinical activity) could enable drug candidates to be assessed earlier for in vivo human pharmacokinetics and metabolism. Moreover, accelerator mass spectrometry (AMS), nuclear magnetic resonance (NMR) spectroscopy and positron emission tomography (PET) are potentially useful spectrometric and imaging methods that can be used in conjunction with such human studies. Some, limited animal tests would still be required before pre-Phase I microdose studies, to take account of the potential risk posed by completely novel chemicals. The workshop recommended that very early volunteer studies using microdoses should be introduced into the drug development process in a way that does not compromise volunteer safety or the scientific quality of the resulting safety data. This should improve the selection of drug candidates and also reduce the likelihood of later candidate failure, by providing in vivo human ADME data, especially for pharmacokinetics and metabolism, at an earlier stage in drug development than is currently the case.

Potential role for P-glycoprotein in the non-proportional pharmacokinetics of UK-343,664 in man

1. UK-343,664 is a potent and specific PDE5 inhibitor. Following single oral doses to human volunteers, it exhibited non-proportional pharmacokinetics over the dose range 30-800 mg. Over this 27-fold dose range, Cmax and AUCt increased 247- and 287-fold respectively. The half-life (4-6 h) was similar at all doses. No systemic exposure was quantifiable at doses <10 mg. 2. UK-343,664 is a lipophilic molecule (log D7.4 = 3.1) and as such is expected to be cleared mainly by metabolism. Based on studies with expressed human P450 enzymes it was concluded that the metabolism of UK-343,664 was predominantly mediated by CYP3A4. With a moderate Km = 76 microM for this enzyme, saturation of first-pass metabolism alone was considered unlikely to account for the non-proportional pharmacokinetics. 3. UK-343,664 showed high affinity for P-glycoprotein in vitro, with a Km = 7.3 microM. In transport studies in LLC-PK1 cell monolayers transfected with P-glycoprotein, UK343,664 showed marked polarized transport which was concentration dependent. 4. The high affinity of UK-343,664 for P-glycoprotein is considered to be the primary source of the non-proportional pharmacokinetic profile observed in man.

Effect of cimetidine and ranitidine on pharmacokinetics and pharmacodynamics of a single dose of dofetilide

AIMS

The aim of this open-label, placebo-controlled, randomized, four-period crossover study was to determine the effects of cimetidine and ranitidine on the pharmacokinetics and pharmacodynamics of a single dose of dofetilide.

METHODS

Twenty healthy male subjects received 100 or 400 mg twice daily of cimetidine, 150 mg twice daily of ranitidine, or placebo for 4 days. On the second day, a single oral 500 microg dose of dofetilide was administered immediately after the morning doses of cimetidine, ranitidine, or placebo. Treatment periods were separated by 1-2 weeks. Pharmacokinetic parameters were determined from plasma and urinary dofetilide concentrations; prolongation of the QTc interval was determined from three-lead electrocardiograms.

RESULTS

Ranitidine did not significantly affect the pharmacokinetics or pharmacodynamics of dofetilide; however, a dose-dependent increase in exposure to dofetilide was observed with cimetidine. When dofetilide was administered with 100 and 400 mg of cimetidine, the area under the plasma concentration-time curve of dofetilide increased by 11% and 48% and the maximum plasma dofetilide concentration increased by 11% and 29%, respectively. The respective cimetidine doses reduced renal clearance of dofetilide by 13% and 33% and nonrenal clearance by 5% and 21%. Dofetilide-induced prolongation of the QTc interval was enhanced by cimetidine; the mean maximum change in QTc interval from baseline was increased by 22% and 33% with 100 and 400 mg of cimetidine, respectively. However, the relationship between the prolongation of the QTc interval and plasma dofetilide concentrations was unaffected by cimetidine or ranitidine; a 1 ng ml-1 increase in plasma dofetilide concentration produced a 17-19 ms prolongation of the QTc interval. Dofetilide was well tolerated, with no treatment-related adverse events or laboratory abnormalities.

CONCLUSIONS

These results suggest that cimetidine increased dofetilide exposure by inhibiting renal tubular dofetilide secretion, whereas ranitidine did not. This effect is not an H2-receptor antagonist class effect but is specific to cimetidine. If therapy with an H2-receptor antagonist is required, it is recommended that cimetidine at all doses be avoided; since ranitidine has no effect on dofetilide pharmacokinetics or prolongation of the QTc interval, it can be seen as a suitable alternative.

Satellite monitoring of desert plant community response to moisture availability

Our study demonstrates the utility of coarse spatial-resolution satellite spectra for analysis of vegetation phenophases and response to moisture availability in an arid ecosystem. We show the feasibility of deriving information on vegetation parameters such as stress and growth patterns in arid regions through the use of satellite-derived vegetation indices, despite the usual problems associated with a high ratio of soil to vegetation cover. Vegetation in our study area consists of Chihuahuan Desert grassland and scrub, including extensive zones of mixed desert scrub and grassland. Historic vegetation change has been well documented and is exemplified by decreasing grass cover and increasing shrub cover, a general trend of desertification. Our analysis suggests that satellite-based inputs can be used to improve our understanding of the spatial dynamics of climatic impacts on natural vegetation and to help us distinguish these processes from human-caused desertification.

The influence of age on the pharmacokinetics of the antiepileptic agent oxcarbazepine

The disposition of oxcarbazepine was studied in 12 young and 12 elderly healthy male and 12 young and 12 elderly healthy female volunteers, with emphasis on the influence of age. Oxcarbazepine was administered as a single dose of either 300 mg (men) or 600 mg (women), followed by multiple-dose (300 mg) administration twice a day for 7 days (men) or 6 days (women). Semilogarithmic plasma concentration-time curves showed an increasing decline at decreasing concentrations. Accumulation of the pharmacologically active metabolite monohydroxycarbamazepine was found to be more than one would anticipate on the basis of linear and unchanged pharmacokinetics. Saturation did not seem to occur at the level of renal excretion. No apparent differences between male and female volunteers were observed. A significant higher maximum concentration, higher area under the curve parameters, and a lower elimination rate constant were observed in the elderly. These observations are in line with a smaller renal clearance of monohydroxycarbamazepine in the elderly group. In a clinical situation, these age-related differences are not likely to have important implications. In general, treatment with oxcarbazepine was well tolerated.

Early lymphopenia in burned children with and without the toxic shock syndrome

The white cell count (WCC) response to thermal injury in children in week 1 postburn has been investigated in a prospective study of 33 patients. Two of these patients developed the toxic shock syndrome (TSS) and, together with seven previously diagnosed cases of the TSS, were studied as a separate group. The WCC response in the non-TSS (control) patients was compared with the response observed in the TSS group. In all patients there was an initial leucocytosis followed by a fall in WCC to a nadir between days 2 and 4. The nadir was significantly lower in the TSS group than that observed in the control group. A rise in the WCC was observed over the following 3-4 days in both groups. In the control group the changes in the WCC were mainly attributable to changes in the granulocyte count with little change in the lymphocyte count. There were similar changes in the granulocyte count in the TSS group but, in contrast to the control group, the lymphocyte count fell, to below the normal range, on day 3. The lowest lymphocyte count observed in the TSS group was significantly lower than that seen in the control group. The observation of a profound fall in the total WCC, granulocytes, and in particular the lymphocytes, between days 2 and 4 are additional factors that may help with the diagnosis of TSS.

Electrical burns to the hand from lawn-mowers

Fifteen cases of electrical burns to the hand are described resulting from the use of electric lawn-mowers. These injuries caused significant morbidity and time off work, and one death. Most of the burns appear to have been preventable, and ways of averting these injuries are discussed.

Serum cholinesterase levels after thermal injury. Is treatment required?

Changes in serum cholinesterase (also known as pseudo- or non-specific cholinesterase) activity have been measured in 20 patients after thermal injury. In 19 patients a marked fall was noted at around day 5 post-burn, and recovery to normal levels was variable and in some cases prolonged. A variety of symptoms, for example, dyspnoea and confusion, have been attributed to lowered serum cholinesterase activity and some workers have gone so far as to advocate blood transfusion to treat such a condition (Price et., 1970; Frohlich, 1977). In this study we found 13 patients (65 per cent) with such symptoms coexisting with a low serum cholinesterase activity. However, we do not believe these symptoms were directly attributable to the low enzyme activity for the following reasons: In only three of the 13 patients were symptoms observed at times when the lowest cholinesterase activity was recorded. A conventional explanation for these symptoms was available, except in three cases with abdominal distension. In six cases no symptoms were observed despite very low cholinesterase levels.

Burns from buried electric cables

Twenty-six patients who sustained significant burn injuries as a result of striking underground electric cables are reviewed. This study sets out to highlight why such injuries occur and to recommend preventive measures to those digging in the London area. There were three deaths in this series.

IgG subclass levels in thermally injured children

In the light of the recognition of Toxic Shock Syndrome occurring in burned children in our Unit, IgG subclass levels were monitored during the first week post burn in a group of 16 children. There were marked differences between some of the subclasses.

The use of the mini-tracheotomy technique in burned patients

Our experience with two patients suggests that the mini-tracheotomy is a very useful technique, and may be of great value in the treatment of sputum retention (with or without inhalation injury) in burn patients.

The toxic shock syndrome in burned children

Seven cases of presumed Toxic Shock Syndrome (TSS), occurred in burned children admitted to the Regional Burn Unit at St Andrew's Hospital, Billericay. Four patients died, and three caused concern. 30 per cent of Staphylococcus aureus isolates available for retrospective study were found to be toxin producing. On reviewing children in this age group admitted between September 1982 and April 1984 we feel that a form of TSS has occurred commonly, in some cases where the burned area was less than 5 per cent. Certain recommendations are made.

Pulmonary candidiasis complicating a severe burn treated with miconazole

A 33/4-year-old boy received a 50 per cent body surface area burn in a house fire. On the eighteenth day post burn he was moribund and a diagnosis of pulmonary candidiasis was made following tracheal cultures and X-ray changes after a period of progressive deterioration during which he had received multiple antibiotics and assisted ventilation. Treatment of this pulmonary candidiasis was with intravenous miconazole. The child's clinical condition rapidly improved over the following 24-48 hours and the X-ray changes resolved. He was subsequently discharged fully healed.