Effects of different types of zinc supplement on the growth, incidence of diarrhea, immune function, and rectal microbiota of newborn dairy calves.

Neonatal diarrhea in dairy calves causes huge economic and productivity losses in the dairy industry. Zinc is an effective anti-diarrheal agent, but high doses may pose a threat to the environment. Therefore, we aimed to evaluate the effects of low-dose zinc supplementation on the growth, incidence of diarrhea, immune function, and rectal microbiota of newborn Holstein dairy calves. Thirty newborn calves were allocated to either a control group (without extra zinc supplementation), or groups supplemented with either 104 mg of zinc oxide (ZnO, equivalent to 80 mg of zinc/d) or 457 mg of zinc methionine (Zn-Met, equivalent to 80 mg of zinc/d) and studied them for 14 d. The rectal contents were sampled on d 1, 3, 7, and 14, and blood samples were collected at the end of the study. Supplementation with ZnO reduced the incidence of diarrhea during the first 3 d of life, and increased serum IgG and IgM concentrations. The Zn-Met supplementation increased growth performance and reduced the incidence of diarrhea during the first 14 d after birth. The results of fecal microbiota analysis showed that Firmicutes and Proteobacteria were the predominant phyla, and Escherichia and Bacteroides were the dominant genera in the recta of the calves. As the calves grew older, rectal microbial diversity and composition significantly evolved. In addition, dietary supplementation with ZnO reduced the relative abundance of Proteobacteria in 1-d-old calves, and increased that of Bacteroidetes, Lactobacillus, and Faecalibacterium in 7-d-old calves, compared with the control group. Supplementation with Zn-Met increased the relative abundance of the phylum Actinobacteria and the genera Faecalibacterium and Collinsella on d 7, and that of the genus Ruminococcus after 2 wk, compared with the control group. Thus, the rectal microbial composition was not affected by zinc supplementation but significantly evolved during the calves' early life. Zinc supplementation reduced the incidence of diarrhea in young calves. In view of their differing effects, we recommend ZnO supplementation for dairy calves during their first 3 d of life and Zn-Met supplementation for the subsequent period. These findings suggest that zinc supplementation may be an alternative to antibacterial agents for the treatment of newborn calf diarrhea.

Effect of Lonicera japonica extract on lactation performance, antioxidant status, and endocrine and immune function in heat-stressed mid-lactation dairy cows.

Here, we examined the effects of Lonicera japonica extract (LJE) on lactation performance, antioxidant status, and endocrine and immune function in heat-stressed mid-lactation dairy cows. Twenty-four healthy Chinese Holstein mid-lactation dairy cows, all with similar milk yield (30.0 ± 1.0 kg/d), parity (2.5 ± 0.3), and days in milk (105 ± 5 d) were allocated to 4 groups using a randomized complete block design: a negative control group (without LJE supplementation; CON) and groups that received LJE at 14, 28, and 56 g/d. The experiment lasted 10 wk over a hot summer, with a pre-feeding period of 2 wk. Cows were exposed to heat stress, as the average temperature-humidity index was greater than 72. The results showed that LJE had no effect on respiration rate; however, it reduced the rectal temperature of dairy cows experiencing heat stress in both a linear and quadratic manner; the lowest (39.03°C) was recorded for the LJE-28 group, lower than the CON group. Supplementation with LJE did not affect dry matter intake, milk yield, or milk composition. The majority of biochemical parameters in serum were unaffected by supplementation with different amounts of LJE; the exception was creatinine, which was reduced quadratically. Compared with the CON group, serum triiodothyronine concentrations increased significantly in the LJE-28 group. Addition of LJE to the diet increased thyroxine concentrations quadratically; values peaked at 18.62 ng/mL in the LJE-28 group. Furthermore, supplementation with increasing amounts of LJE quadratically increased the activity of glutathione peroxidase and total antioxidant capacity in serum but decreased concentration of malondialdehyde. Although we detected no differences in the concentrations of IgA, IgM, or cytokines, dairy cows in the LJE-28 group had higher IgG and IL-4 concentrations than did cows in the CON group. Supplementation with LJE increased concentrations of IgG and IL-4 in the serum quadratically but decreased that of IL-2. Finally, heat shock protein 72 concentrations in the serum tended to fall quadratically as the amount of LJE increased. In summary, LJE had no negative effects on lactation performance but helped to alleviate heat stress by improving antioxidant status and promoting endocrine and immune functions. Supplementation with LJE at 28 g/d is recommended for lactating dairy cows experiencing heat stress during hot summers.

Randomized trial of tamoxifen alone or combined with aminoglutethimide and hydrocortisone in women with metastatic breast cancer.

A randomized clinical trial was performed to compare the efficacy of tamoxifen (TAM) alone with that of TAM plus aminoglutethimide (AG) and hydrocortisone (HC). Patients failing TAM could receive AG and HC. Objective responses to therapy were seen in 21 of 49 TAM patients (43%) and 25 of 51 TAM, AG and HC patients (49%). Time to disease progression and survival distributions were not significantly different between the treatment arms. Toxicity was greater for patients treated with TAM, AG, and HC and the trial was discontinued early for this reason. Twenty-four patients received AG and HC after TAM therapy and three (12%) achieved a response. We conclude that the combination of TAM, AG, and HC is not recommended over TAM alone because toxicity appears to outweigh any potential therapeutic advantage.

Randomized trial of bilateral oophorectomy versus tamoxifen in premenopausal women with metastatic breast cancer.

A randomized clinical trial was performed to compare the efficacy of bilateral oophorectomy with that of tamoxifen at a dose of 10 mg twice daily in premenopausal women with metastatic breast cancer, and to examine the efficacy of each as a crossover treatment. Initial treatment responses were seen in ten of 27 patients (37%) treated with oophorectomy and seven of 26 patients (27%) treated with tamoxifen. The difference was not statistically significant. Crossover responses were seen in five of 15 patients (33%) treated with oophorectomy, including three responses in ten prior tamoxifen nonresponders; and two of 18 patients (11%) treated with tamoxifen. Time to progression distributions were not significantly different during initial treatment, and no significant differences in survival were noted. Thus, there was no overall disadvantage to the use of tamoxifen as opposed to oophorectomy as initial hormonal therapy, and a failure to respond to tamoxifen did not preclude a response to subsequent oophorectomy. Exploratory data analysis within subsets indicated consistent differential treatment effects in the visceral dominant patients. Of the 16 such patients treated with oophorectomy, eight (50%) experienced objective responses but there were no responses in the 14 patients treated with tamoxifen. In the nine visceral dominant crossover patients who had not responded to initial tamoxifen, three (33%) subsequently responded to oophorectomy. Time to progression distributions within the visceral dominant subset appeared to be better for the patients treated initially with oophorectomy. However, one must be very cautious in drawing conclusions from exploratory subset analyses, especially with the small sample size. Further studies would be required to test any hypothesis of differential organ site responsiveness.

Pharmacokinetic interactions of cyclosporine with etoposide and mitoxantrone in children with acute myeloid leukemia.

The purpose of this study was to assess the effect of the multidrug resistance modulator cyclosporine (CsA) on the pharmacokinetics of etoposide and mitoxantrone in children with de novo acute myeloid leukemia (AML). Serial blood samples for pharmacokinetic studies were obtained in 38 children over a 24-h period following cytotoxin treatment with or without CsA on days 1 and 4. Drug concentrations were quantitated using validated HPLC methods, and pharmacokinetic parameters were determined using compartmental modeling with an iterative two-stage approach, implemented on ADAPT II software. Etoposide displayed a greater degree of interindividual variability in clearance and systemic exposure than mitoxantrone. With CsA treatment, etoposide and mitoxantrone mean clearance declined by 71% and 42%, respectively. These effects on clearance, in combination with the empiric 40% dose reduction for either cytotoxin, resulted in a 47% and 12% increases in the mean AUC for etoposide and mitoxantrone, respectively. There were no differences in the rates of stomatitis or infection between the two groups. CsA treatment resulted in an increased incidence of hyperbilrubinemia, which rapidly reversed upon conclusion of drug therapy. The variability observed in clearance, combined with the empiric 40% dose reduction of the cytotoxins, resulted in statistically similar systemic exposure and similar toxicity.

Antioxidant-based inhibitors of leukotriene biosynthesis. The discovery of 6-[1-[2-(hydroxymethyl)phenyl]-1-propen-3-yl]-2,3-dihydro-5- benzofuranol, a potent topical antiinflammatory agent.

The leukotrienes, metabolites of arachidonic acid produced through the action of the enzyme 5-lipoxygenase, are important mediators of immediate hypersensitivity and inflammation. Among the variety of diseases in which the leukotrienes may play a symptomatic or causative role is the dermatological condition psoriasis, a chronic proliferative disease of the skin. This study reports the synthesis and comparative biological activities of various ortho-substituted phenols including 4-methoxyphenols, 6-hydroxy-1,2,3,4-tetrahydrobenzopyrans, 2,3-dihydro-5-benzofuranols, and 5-benzofuranols. The phenols prepared in this study were evaluated for their ability to inhibit the production of leukotriene B4(LTB4) in isolated human polymorphonuclear leukocytes (PMNs) and to inhibit a topical inflammatory response in the topical mouse ear (TME) model. In the former case, when the log IC50 was plotted versus the log of the octanol/water partition coefficient (log P), to eliminate the effect of lipophilicity, the 2,3-dihydro-5-benzofuranol ring system was shown to be more potent than the other ring systems examined throughout the range of partition coefficients studied. The ability to inhibit leukotriene production in vitro in human PMNs can be rationalized on the basis of a model that suggests that the observed inhibition is dependent on the kinetic ability of the inhibitor to reduce a radical species and on the fraction of inhibitor that is partitioned into the cell membrane. While the in vivo antiinflammatory activity as measured by the TME did not correlate with the in vitro data, it was felt that the TME represented a valuable measure of the ability of a compound to penetrate the skin to the site of an ongoing inflammatory response. Of the compounds synthesized in this study, 6-[1-[2-(hydroxymethyl)phenyl]-1-propen-3-yl]-2,3-dihydro-5-benzof uranol (1, L-651896) was chosen for further development.

L-652,469--a dual receptor antagonist of platelet activating factor and dihydropyridines from Tussilago farfara L.

L-652,469, 14-acetoxy-7 beta-(3'-ethylcrotonoyloxy)-notonipetranone, isolated from the methylene chloride extracts of the buds of Tussilago farfara L, was found to inhibit both platelet activating factor (PAF) and Ca2+ entry blocker binding to membrane vesicles. It inhibits the [3H]PAF specific binding to rabbit platelet membranes with equilibrium inhibition constants (Ki) of 3.2 and 4.0 microM in the presence of 150 mM NaCl and 10 mM MgCl2 respectively. It is a competitive PAF receptor antagonist with an equilibrium dissociation constant (KB) of 5.16 microM. It also competitively inhibits the specific binding of Ca2+ channel blockers (e.g. [3H]nitrendipine; Ki = 1.2 microM) in cardiac sarcolemmal vesicles. At 10(-5) M, L-652,469 causes a 60% relaxation of Ca2+-induced contraction of rat thoracic aorta strips. Due to its dual antagonistic activities, L-652,469 potently inhibits the gel-filtered rabbit platelet aggregation with a pA2 of 5.79. It was also found to be orally active with a beneficial effect to inhibit the PAF-induced rat foot edema and the first phase of carrageenan-induced rat hindpaw edema.

Evaluation of bisantrene administered by 72-hour infusion in women with metastatic breast cancer.

Bisantrene was administered by 72-h continuous infusion at a dosage level of 240 mg/m2 to 17 patients with metastatic breast cancer who had received only one prior chemotherapy regimen and no prior doxorubicin. Three patients (18%) achieved partial regressions lasting 51, 106, and 213 days. For all patients, the median time to disease progression was 83 days and median survival was 280 days. Eleven patients received doxorubicin after removal from protocol and were evaluable for response, and four (36%) achieved a partial regression. We conclude that bisantrene administered by the method we employed is not associated with substantial clinical benefit in this population of patients.

A stochastic model for analyzing prevalence surveys of hepatitis A antibody.

Epidemiologic surveys of the age-specific prevalence of antibody to hepatitis A virus (anti-HAV) provide information on the spread of infection such as the infection rate and age-dependent characteristics. However, the data on prevalence are confounded with the mortality and diminished immunity of surveyed individuals. Through modeling, the age-specific prevalence of an individual can be separated from these confounding factors. A Markov chain is used to model the process of acquisition of anti-HAV by an individual and to derive the age-specific prevalence. Data from Frösner et al. [Am. J. Epidemiol. 110:63-69 (1979)] are used for illustration and estimation of parameters. The model offers an explanation of the well-known phenomenon of a decline in prevalence in older age. In addition to hepatitis, the framework of the model can be adapted to analyzing seroepidemiologic surveys of other diseases.

The isolation and characterization of kadsurenone from haifenteng (Piper futokadsura) as an orally active specific receptor antagonist of platelet-activating factor.

A natural product, kadsurenone, was isolated from the Chinese herbal preparation haifenteng (Caulis piperis futokadsurae) and characterized as an orally-active specific antagonist of the platelet-activating factor (PAF). Kadsurenone inhibits the specific binding of 3H-PAF to a receptor preparation from rabbit platelet membrane in a competitive and reversible manner, its Ki being 3.88 X 10(-8) M. It inhibits the aggregation of rabbit platelets in plasma induced by PAF with a pA2 of 6.28, but not those induced by arachidonic acid, epinephrine, ADP or A-23187. It inhibits the aggregation of isolated human neutrophils with a pA2 of 6.32. It also inhibits PAF-induced degranulation and release of beta-D-glucuronidase at 2-24 microM in vitro. In the rat, kadsurenone at 8-40 mg/kg i.p. inhibits the increases of plasma lysosomal enzymes and haematocrit induced by intravenous PAF. In the guinea pig, kadsurenone at 25-50 mg/kg p.o. reduces the increase of cutaneous vascular permeability induced by PAF. These results indicate that kadsurenone is a specific and effective receptor antagonist of PAF in several in vitro and in vivo systems.

Confidence intervals for a normal mean following a group sequential test.

This paper presents methodology based on the likelihood-ratio test, developed for construction of confidence intervals for a normal mean, following a group sequential test. Examples show that the confidence intervals produced by this method have accurate nominal probability of coverage and have generally shorter average length than that produced by Tsiatis, Rosner, and Mehta (1984, Biometrics 40, 797-803).

Interim analysis for randomized clinical trials: simulating the predictive distribution of the log-rank test statistic.

This paper presents an analog to stochastic curtailment, where the simulation of the remaining trial data from interim analysis is constructed using the existing data, rather than the design planning parameters. The nonparametric approach for the predictive distribution as proposed by Berliner and Hill (1988, Journal of the American Statistical Association 83, 772-779) forms the basis of the procedure. The methods are applied retrospectively to a clinical trial in childhood cancer.

Specific binding of [3H]dihydrokadsurenone to rabbit platelet membranes and its inhibition by the receptor agonists and antagonists of platelet-activating factor.

Kadsurenone inhibits specifically and competitively the specific binding of 3H-labeled platelet-activating factor ([3H]PAF) to rabbit platelet membranes. Since the 5-propyl analog of kadsurenone (dihydrokadsurenone) retains roughly the same potency as kadsurenone, [3H]dihydrokadsurenone was therefore synthesized through tritiation of kadsurenone. Specific binding of [3H]dihydrokadsurenone in rabbit platelet membranes is saturable. Scatchard analysis of binding data reveals the presence of a single class of binding sites with an equilibrium dissociation constant (KD) of 16.81 ( +/- 0.57) nM. The total number (Bmax) of detectable binding sites is 2.27 ( +/- 0.09) pmol/mg protein. Both C16- and C18-PAF fully displace the specific binding of (3H]dihydrokadsurenone (5 nM) with an identical ED50 of 3.6 X 10(-9) M. Dihydrokadsurenone and kadsurenone also displace the specific binding with roughly the same potency (ED50 = 4.4 X 10(-8) M). Several other PAF analogs and PAF receptor antagonists tested show relative potencies roughly similar to those found in the [3H]PAF-specific binding assay. Other pharmacological agents with no PAF antagonistic activities did not inhibit the specific binding of [3H]dihydrokadsurenone. These results agree with our previous conclusion that kadsurenone is a specific and competitive receptor antagonist and strongly suggest that PAF and the PAF receptor antagonists tested may interact at a common binding site in the PAF receptor.

Confidence intervals following group sequential tests.

A procedure is proposed for obtaining confidence intervals for the probability of response following completion of a group sequential phase II trial. Numerical examples showed that, by ordering the sample space using the likelihood principle, we are able to shorten the length of the intervals and to obtain more accurate coverage of probability relative to previously proposed methods. The method may also be used for interval estimation following phase III trials.

Reduction in burden of illness: a new efficacy measure for prevention trials.

A new efficacy measure is developed for use in prevention trials of interventions which may affect both disease incidence and disease severity. We assign a severity score to each incident case and sum severity scores over all incident cases within each treatment group to create a burden-of-illness score for each treatment group. Efficacy is evaluated by the difference between the burden-of-illness per randomized subject in the two randomized treatment groups. Since the numbers of summands in each burden-of-illness score is a random variable, standard methods of analysis are not directly applicable. The asymptotic distribution and sampling properties of the net reduction in the burden-of-illness score are derived for trials designed to stop either after a fixed length of follow-up or after the occurrence of a fixed number of cases. We illustrate the method with data from a clinical trial of a human rotavirus vaccine.

The bias of the sample proportion following a group sequential phase II clinical trial.

Group sequential testing procedures have seen wide use in Phase II clinical trials. The sample proportion p of responders is the commonly used estimator for the binomial response probability p. It can be shown that p is the maximum likelihood estimator (MLE) of p. It is well known that MLE can be in general (Whitehead) and p in particular (Dupont) biased estimators, if ther computation follows a group sequential procedure. In this paper we numerically investigate the bias of p. We find that the magnitude of the bias of p is less than 0.025 in all cases we investigated. We apply the idea in Whitehead to propose a bias-adjusted estimator that reduces the bias substantially and reduces the mean square error as well in a certain range of p. We also evaluate the uniformly minimum variance unbiased (UMVU) estimator. If one does not mind a bias of 0.025, one may find the sample proportion a suitable estimator for p because of its simplicity and easy explanation. If one is concerned with bias, the bias-adjusted estimator may be a good choice.