The role of variability in evaluating ultra high dilution effects: considerations based on plant model experiments

Effects of Homeopathic Preparations of Mercurius corrosivus on the Growth Rate of Moderately Mercury-Stressed Duckweed Lemna gibba L

Background  A bioassay with severely mercury-stressed duckweed ( Lemna gibba L.) had revealed growth-inhibiting effects of homeopathically potentised mercury(II) chloride ( Mercurius corrosivus, Merc-c. ). We hypothesised that effects of potentised preparations are dependent on the stress level of the organisms used in the bioassay. The aim of the present investigation was to examine the response of duckweed to potentised Merc-c. at a lower stress level.

Methods  Duckweed was moderately stressed with 2.5 mg/L mercury(II) chloride for 48 hours. Afterwards plants grew in either Merc-c. (seven different potency levels, 24x–30x) or water controls (unsuccussed or succussed water) for 7 days. Growth rates of the frond (leaf) area were determined using a computerised image-analysis system for day 0–3 and 3–7. Three independent experiments with potentised Merc-c. and three systematic negative control experiments were performed. All experiments were randomised and blinded.

Results  Unsuccussed and succussed water did not significantly differ in their effects on duckweed growth rate. The systematic negative control experiments did not yield any significant effects, thus providing evidence for the stability of the experimental system. Data from the two control groups and the seven treatment groups ( Merc-c. 24x–30x) were each pooled to increase statistical power. Duckweed growth rates for day 3–7 were enhanced ( p  < 0.05) after application of Merc-c. compared with the controls. Growth rates for day 0–3 were not influenced by the homeopathic preparations.

Conclusions  Moderately mercury-stressed Lemna gibba L. yielded evidence of growth-enhancing specific effects of Merc-c. 24x–30x in the second observation period (day 3–7). This observation is complementary to previous experiments with severely mercury-stressed duckweed, in which a decrease in growth was observed in the first observation period (day 0–3). We hypothesise that the differing results are associated with the level of stress intensity (moderate vs. severe).

Reproducibility of the effects of homeopathically potentised Argentum nitricum on the growth of Lemna gibba L. in a randomised and blinded bioassay

BACKGROUND

A previous study reported a significant statistical interaction between experiment date and treatment effect of Argentum nitricum 14x-30x on the growth rate of duckweed (Lemna gibba L.). The aim of the present study was to investigate the stability of the test system and intra-laboratory reproducibility of the effects found.

METHODS

Duckweed was treated with A. nitricum potencies (14x-30x) as well as succussed and unsuccussed water controls. The outcome parameter area-related growth rate for day 0-7 was determined by a computerised image analysis system in two series of independent randomised and blinded experiments. Systematic negative control (SNC) experiments were carried out to investigate test system stability. Statistical analysis was performed with full two-way analysis of variance (ANOVA) and protected Fisher's Least Significant Difference (LSD) test.

RESULTS

In the first repetition series we found a significant treatment effect (p = 0.016), while in the second series no effect was observed. The negative control experiments showed that the experimental system was stable. An a posteriori subgroup analysis concerning gibbosity revealed the importance of this growth state of L. gibba for successful reproduction of the statistically significant interaction in the original study; flat: no interaction (p = 0.762); slight gibbosity: no interaction (p = 0.356); medium gibbosity: significant interaction (p = 0.031), high gibbosity: highly significant interaction (p = 0.005).

CONCLUSIONS

With the original study design (disregarding gibbosity status of L. gibba) results of the original study could not be reproduced sensu stricto. We conclude that the growth state gibbosity is crucial for successful reproduction of the original study. Different physiological states of the test organisms used for bioassays for homeopathic basic research must carefully be considered.

Number of succussion strokes affects effectiveness of ultra-high-diluted arsenic on in vitro wheat germination and polycrystalline structures obtained by droplet evaporation method

OBJECTIVES

The aim of this study is to investigate whether the number of succussion strokes applied after each dilution step when preparing the homeopathic treatments influences the effectiveness of ultra-high-diluted (UHD) arsenic trioxide at the 45th decimal dilution/dynamization (As₂O₃ 45x).

DESIGN

Wheat seeds, previously stressed with ponderal As₂O₃, were treated with: As₂O₃ 45x, H₂O 45x (dynamized control), or pure water (negative control). The succussion was done manually, and various succussion durations (numbers of strokes) were tested for each treatment. Treatment effectiveness was tested blind using the in vitro germination test and the droplet evaporation method (DEM). Data were processed by the Poisson test (germination test) and by two-way analysis of variance (DEM).

MAIN OUTCOME MEASURES

We evaluated both the in vitro germination rate, by counting the non-germinated seeds, and the complexity of polycrystalline structures (PCS) (local connected fractal dimension (LCFD)) obtained by evaporating leakage droplets from stressed seeds that had been watered with the different treatments.

RESULTS

We observed a highly significant increase in germination rate when the number of strokes (N_S) was ≥32 for both As₂O₃ 45x and H₂O 45x, and a significant increase in the LCFD of PCS for As₂O₃ 45x when the N_S was ≥32 and for H₂O 45x when it was 70.

CONCLUSIONS

Both experimental approaches showed increased effectiveness for treatments prepared with a higher number of succussion strokes. These results indicate that succussion may have an important influence on treatment effectiveness, and so highlight the need for further research.

Wheat and ultra high diluted gibberellic acid--further experiments and re-analysis of data

BACKGROUND

Following studies (a) on wheat seedlings and ultra high diluted silver nitrate, and (b) on amphibians and an ultra high diluted hormone, (c) a bio-assay on wheat and extremely diluted gibberellic acid was standardized. This assay was intended to combine the easy-to-handle aspect of (a) and biologically interesting aspects of (b). The purpose of the data analysis presented here was to investigate the influence of an extreme dilution of gibberellic acid on wheat stalk length and to determine the influence of external factors on the experimental outcome.

METHODS

Grains of winter wheat (Triticum aestivum, Capo variety) were observed under the influence of extremely diluted gibberellic acid (10(-30)) prepared by stepwise dilution and agitation according to a protocol derived from homeopathy ('G30x'). Analogously prepared water was used for control ('W30x'). 16 experiments including 8000+8000 grains were performed by 9 researchers.

RESULTS

Experiments that were performed between January and April showed inconsistent results, whereas most of the experiments performed between September and December showed shorter stalks in the G30x group. This was confirmed by correlation analysis (p<0.01). Thus winter/spring experiments and autumn experiments were analysed separately. When all 10 autumn experiments were pooled, mean stalk lengths (mm) were 48.3±21.4 for the verum group and 52.1±20.4 for control (mean±SD) at grain level (N=5000 per group) and ±5.3 and ±5.1 respectively at dish level. In other words, verum stalk length (92.67%) was 7.33% smaller than control stalk length (100%). The effect size is small when calculation is done on the basis of grains (d=0.18) but, due to the smaller SD at dish level, medium when done on the basis of dishes (d=0.73). The inhibiting effect was observed by 6 of the 6 researchers who performed the autumn experiments.

CONCLUSION

The model may be useful for further research as there exists a theoretical justification due to previous studies with wheat and extremely diluted silver nitrate, as well as to previous studies with amphibians and diluted hormones, and its methods are well standardized. Data confirm the hypothesis that information can be stored in the test liquid, even at a dilution of the original substance beyond Avogadro's value; and that the wheat bio-assay is sensitive to such information.

The use of plant-based bioassays in homeopathic basic research

OBJECTIVES

The objective was to evaluate homeopathic basic research studies that use plant-based bioassays. With this in view, a compilation was made of the findings of three systematic literature reviews covering plant-based bioassays in the three fields of healthy, abiotically, or biotically stressed plants. This compilation focused on investigations using advanced experimental methods and detailed descriptions, also with the aim of supporting the design of future experiments.

METHODS

Publications included had to report on studies into the effects of homeopathic preparations on whole plants, seeds, plant parts and cells. Outcomes had to be measured by established procedures and statistically evaluated. A Manuscript Information Score (MIS) was applied using predefined criteria to identify publications with sufficient information for adequate interpretation (MIS ≥ 5). Additional evaluation focused on the use of adequate controls to investigate specific effects of homeopathic preparations, and on the use of systematic negative control (SNC) experiments to ensure the stability of the bioassay. Only a fraction of the studies reported here were performed with 'ultra high' dilutions, whereas other studies were performed with moderate or high dilutions.

RESULTS

A total of 157 publications were identified, describing a total of 167 experimental studies. 84 studies included statistics and 48 had a MIS ≥ 5, thus allowing adequate interpretation. 29 studies had adequate controls to identify specific effects of homeopathic preparations, and reported significant effects of decimal and centesimal homeopathic potencies, including dilution levels beyond Avogadro's number. 10 studies reported use of SNC experiments, yielding evidence for the stability of the experimental set-up.

CONCLUSION

Plant models appear to be a useful approach for investigating basic research questions relating to homeopathic preparations, but more independent replication trials are needed in order to verify the results found in single experiments. Adequate controls and SNC experiments should be implemented on a routine basis to exclude false-positive results.

Replications of fundamental research models in ultra high dilutions 1994 and 2015--update on a bibliometric study

INTRODUCTION

This paper focuses exclusively on experimental models with ultra high dilutions (i.e. beyond 10(-23)) that have been submitted to replication scrutiny. It updates previous surveys, considers suggestions made by the research community and compares the state of replication in 1994 with that in 2015.

METHODS

Following literature research, biochemical, immunological, botanical, cell biological and zoological studies on ultra high dilutions (potencies) were included. Reports were grouped into initial studies, laboratory-internal, multicentre and external replications. Repetition could yield either comparable, or zero, or opposite results. The null-hypothesis was that test and control groups would not be distinguishable (zero effect).

RESULTS

A total of 126 studies were found. From these, 28 were initial studies. When all 98 replicative studies were considered, 70.4% (i.e. 69) reported a result comparable to that of the initial study, 20.4% (20) zero effect and 9.2% (9) an opposite result. Both for the studies until 1994 and the studies 1995-2015 the null-hypothesis (dominance of zero results) should be rejected. Furthermore, the odds of finding a comparable result are generally higher than of finding an opposite result. Although this is true for all three types of replication studies, the fraction of comparable studies diminishes from laboratory-internal (total 82.9%) to multicentre (total 75%) to external (total 48.3%), while the fraction of opposite results was 4.9%, 10.7% and 13.8%. Furthermore, it became obvious that the probability of an external replication producing comparable results is bigger for models that had already been further scrutinized by the initial researchers.

CONCLUSIONS

We found 28 experimental models which underwent replication. In total, 24 models were replicated with comparable results, 12 models with zero effect, and 6 models with opposite results. Five models were externally reproduced with comparable results. We encourage further replications of studies in order to learn more about the model systems used.

Reproducibility of effects of homeopathically potentised gibberellic acid on the growth of Lemna gibba L. in a randomised and blinded bioassay

BACKGROUND

Reproducibility of basic research investigations in homeopathy is challenging. This study investigated if formerly observed effects of homeopathically potentised gibberellic acid (GA3) on growth of duckweed (Lemna gibba L.) were reproducible.

METHODS

Duckweed was grown in potencies (14x-30x) of GA3 and one time succussed and unsuccussed water controls. Outcome parameter area-related growth rate was determined by a computerised image analysis system. Three series including five independent blinded and randomised potency experiments (PE) each were carried out. System stability was controlled by three series of five systematic negative control (SNC) experiments. Gibbosity (a specific growth state of L. gibba) was investigated as possibly essential factor for reactivity of L. gibba towards potentised GA3 in one series of potency and SNC experiments, respectively.

RESULTS

Only in the third series with gibbous L. gibba L. we observed a significant effect (p = 0.009, F-test) of the homeopathic treatment. However, growth rate increased in contrast to the former study, and most biologically active potency levels differed. Variability in PE was lower than in SNC experiments. The stability of the experimental system was verified by the SNC experiments.

CONCLUSIONS

Gibbosity seems to be a necessary condition for reactivity of L. gibba to potentised GA3. Further still unknown conditions seem to govern effect direction and the pattern of active and inactive potency levels. When designing new reproducibility studies, the physiological state of the test organism must be considered. Variability might be an interesting parameter to investigate effects of homeopathic remedies in basic research.

Short-term effects of repeated olfactory administration of homeopathic sulphur or pulsatilla on electroencephalographic alpha power in healthy young adults

INTRODUCTION

Homeopathic pathogenetic trials usually rely on symptom self report measures. Adding objective biomarkers could enhance detection of subtle initial remedy effects. The present feasibility study examined electroencephalographic (EEG) effects of repeated olfactory administration of two polycrest remedies.

METHODS

College student volunteers (ages 18-30, both sexes) from an introductory psychology course were screened for good health and relatively elevated Sulphur or Pulsatilla symptom scores on the Homeopathic Constitutional Type Questionnaire (CTQ). Subjects underwent a series of 3 once-weekly double-blind sessions during which they repeatedly sniffed the remedy matched to their CTQ type and solvent controls. Each remedy was given in a 6c, 12c, and 30c potency, one potency per week, in randomly assigned order. Solvent controls included both plain distilled water and a water-ethanol (95%) solution. All sniff test solutions were further diluted just prior to laboratory sessions (0.5 ml test solution in 150 ml distilled water). Within a session, remedies and control solvents were administered via 2-s sniffs (8 sniffs of each of 4 different succussion levels for the potency in randomized order). Primary outcome variable was relative EEG power (alpha 1 8-10 Hz; alpha 2 10-12 Hz) averaged over 19 electrode sites, including all succussions for a given potency.

RESULTS

Mixed-effect models revealed significant main effects for remedy type (Sulphur >Pulsatilla) in both alpha bands, controlling for gender, baseline resting EEG alpha, and solvent control responses. Additional analyses showed significant nonlinear interactions between dilution and time (weekly session) in alpha 2 for both remedies and alpha 1 for Sulphur.

CONCLUSION

EEG alpha offers an objective biomarker of remedy effects for future studies and potential method for distinguishing time-dependent effects of specific remedies and remedy potencies from one another.

Seasonal variation of the effect of extremely diluted agitated gibberellic acid (10e-30) on wheat stalk growth: a multiresearcher study

The influence of a homeopathic high dilution of gibberellic acid on wheat growth was studied at different seasons of the year. Seedlings were allowed to develop under standardized conditions for 7 days; plants were harvested and stalk lengths were measured. The data obtained confirm previous findings, that ultrahigh diluted potentized gibberellic acid affects stalk growth. Furthermore, the outcome of the study suggests that experiments utilizing the bioassay presented should best be performed in autumn season. In winter and spring, respectively, no reliable effects were found.

The efficacy of ultramolecular aqueous dilutions on a wheat germination model as a function of heat and aging-time

This study evaluates the effects of temperature and aging on the efficacy of As(2)O(3) at the 45th decimal potency in a wheat germination model, compared against a control and potentized H(2)O 45×. Each treatment-temperature combination was tested on seeds (Triticum aestivum L.) of Pandas variety, using six Petri dishes (33 seeds/dish) per trial, performing eight trials. Seeds were pre-treated by poisoning with 0.1% As(2)O(3) solution to reduce germination, to allow a better evaluation of homeopathic treatment effects. The outcome variable was the number of non-germinated seeds after 96 h. Temperature effect was investigated by heating each treatment in a water bath for 30 min (at 20, 40 or 70°C), or for 5 min (at 100°C), and that of aging by dividing experimental data, collected over a period of nearly five months, into two groups: early and late experiments. Results seem to show that the efficacy of As(2)O(3) 45× is unaltered at 20 and 40°C, increases at 70°C and decreases at 100°C. As regards aging, a notable difference was found between early trials, with no significant efficacy, and late trials, where As(2)O(3) 45× exhibits a repeated significant effect versus control, except at 100°C. A reduction in variability was observed for As(2)O(3) 45× at 20°C versus control, confirming the findings of previous work. The main conclusion suggested by this experiment is that the efficacy of As(2)O(3) 45× on wheat germination may be influenced by heating degree and seems to have an increasing trend as a function of aging.

Reporting experiments in homeopathic basic research (REHBaR)--a detailed guideline for authors

BACKGROUND

Reporting experiments in basic research in homeopathy is an important issue as comprehensive description of what exactly was done is required. So far, there is no guideline for authors available, unlike criteria catalogues common in clinical research.

METHODS

A Delphi Process was conducted, including a total of five rounds, three rounds of adjusting and phrasing plus two consensus conferences. European researchers who published experimental work within the last five years were involved.

RESULTS

A checklist of 23 items was obtained and supplemented with detailed examples emphasizing what each item implies. Background, objectives and possible hypotheses should be given in the part 'introduction'. Special emphasis is put on the 'materials and methods' section, where a detailed description of chosen controls, object of investigation, experimental setup, replication, parameters, intervention, allocation, blinding, and statistical methods is required. The section 'results' should present sufficient details on analysed data, descriptive as well as inferential. Authors should discuss their results and give an interpretation in the context of current evidence.

CONCLUSION

A guideline for Reporting Experiments in Homeopathic Basic Research (REHBaR) was compiled to be applied by authors when preparing their manuscripts, and to be used by scientific journals in the reviewing process. Furthermore the guideline is a commitment to a certain minimum quality level needed in basic research, e.g. blinding and randomisation. Feedback is encouraged on applicability, strength and limitations of the list to enable future revisions.

Isopathic treatment effects of Arsenicum album 45x on wheat seedling growth--further reproduction trials

BACKGROUND

Two experimental studies on wheat preintoxicated with Arsenic trioxide yielded a significant shoot growth increase after an isopathic application of Ars-alb 45x. One independent reproduction trial however, yielded an effect inversion: wheat shoot growth was significantly decreased after application of Ars-alb 45x.

AIMS

In this study we investigated the role of three potential confounding factors on the experimental outcome: geographical location of the experiments, influence of the main experimenter, and seed sensitivity to Arsenic poisoning. Laboratory-internal reproducibility was assessed by meta-analysis.

MATERIAL AND METHODS

Wheat poisoned with Arsenic trioxide was cultivated in vitro in either Ars-alb 45x, water 45x, or unpotentised water. Treatments were blinded and randomised. Shoot length was measured after 7 days. The stability of the experimental set-up was assessed by systematic negative control (SNC) experiments.

RESULTS

The SNC experiments did not yield significant differences between the three groups treated with unpotentised water. Thus the experimental set-up seemed to be stable. We did not observe any shoot growth increase after a treatment with Ars-alb 45x in any of the newly performed experiments. In contrast, the meta-analysis of all 17 experiments performed (including earlier experiments already published) yielded a statistically significant shoot growth decrease (-3.2%, p=0.017) with isopathic Ars-alb 45x treatment. This effect was quantitatively similar across all five series of experiments.

CONCLUSIONS

Ultramolecular Ars-alb 45x led to statistically significant specific effects in arsenic poisoned wheat when investigated by two independent working groups. Effect size and effect direction differ, however. The investigated factors (geographical location, experimenter, seed sensitivity to Arsenic poisoning) did not seem to be responsible for the effect inversion. Laboratory external reproducibility of basic research into homeopathic potentisation remains a difficult issue.

Reproducibility of dwarf pea shoot growth stimulation by homeopathic potencies of gibberellic acid

OBJECTIVES

Investigation of the conditions for reproducibility of dwarf pea shoot growth stimulation through homeopathic potencies of gibberellic acid.

METHODS

4 batches of pea seed (Pisum sativum L. cv. Früher Zwerg; harvests from 1997, 1998, 1999, and 2000) were tested regarding their reaction to gibberellic acid 17x and 18x (compared to unsuccussed and succussed water (1x) as controls) in 8 independent randomized and blinded experiments. Pea seed was immersed for 24h in watery solutions of homeopathic potencies or controls, and cultivated under controlled laboratory conditions. Pea shoot length was measured after 14 days. Two systematic negative control experiments assessed the stability of the experimental set-up.

RESULTS

The systematic negative control experiments yielded no significant effects and confirmed the stability of the experimental set-up. 2 out of 4 seed batches reacted to the homeopathic treatment (p<0.05). Seed batch 1997 showed a reproducible reaction to gibberellic acid 17x (shoot length stimulation of +11.2%, p=0.007), and seed batch 1998 showed a significant varying response (increase/decrease). Seed batch 1997 differed from the other 3 batches by an increased glucose and fructose content, and reduced 1000kernel weight. Meta-analysis with data of earlier experiments is in accordance with the results of the present experimental series.

CONCLUSIONS

We identified 'seed quality' as a possible trigger factor for successful reproducibility in homeopathic basic research. Premature harvesting as a possible key factor for responsiveness of dwarf peas to homeopathic potencies of gibberellic acid is our current working hypothesis to be tested in future experiments.