Scientific quality of clinical research an analysis of 40 research projects in pharmacology/pharmacotherapy

Objective: The scientific quality of research is an important ethical issue. To clarify the quality of research projects in pharmacotherapy/pharmacology, 40 randomly selected research projects in pharmacotherapy/pharmacology submitted to a research ethics committee were reviewed. Results: Eight of the projects would not have contributed new knowledge nor were they necessary as controls for the results of previous research. Fifteen of the research protocols were of good quality, 15 could be used after revisions, and 10 were unfit for use. Eleven of the research projects were not finished 5 years after they were started. A written report was produced from 26 of the projects. Nine were of good quality and could be accepted for publication in a medical journal, 10 of the reports were in need of revision before publication, and 7 should not be accepted for publication. Conclusion: Research in this field ought to be improved, and ways to improve the standard of clinical trials in pharmacotherapy are dicussed. Received: 1 April 1996 / Accepted in revised form: 28 June 1996     

Effect of Mutans streptococcal colonization on plaque formation and regrowth in young children--a brief commnunication.

OBJECTIVES: Visible plaque on the maxillary anterior teeth of young children has been identified as a risk indicator for early childhood caries. The present study examined whether this plaque is related to the colonization of children's teeth with Mutans streptococci (MS) or toothbrushing frequency. METHODS: Thirty-nine children, aged 12 to 36 months, had plaque scores, and plaque samples were taken from the labial surfaces of the maxillary incisors at baseline and repeated 3 days after suspended oral hygiene (plaque regrowth). RESULTS: A positive correlation was found between the baseline percent MS and regrowth plaque score and between baseline and regrowth plaque scores. Plaque scores of those that brushed zero to one time a day were not different from those who brushed two or more times a day. CONCLUSIONS: This study suggests that the presence of plaque on the anterior teeth of young children is consistent and related to MS colonization.     

Dielectric properties of some keratinised tissues. Part 2: Human hair

Some electrical properties of human hair have been investigated to determine whether a significant DC electrical conductance is present in keratinised tissues. The DC conductance was found to be substantial and highly dependent on the moisture level in the hair fibres. At high moisture levels, the conductance was found to be almost frequency independent below 1 kHz. Absorption and desorption profiles were also monitored, revealing different stages of sorption mechanisms in the fibres. Although absorption was found to be a slow process with ‘time constants’ in the range of hours, desorption was much faster, in the range of a few minutes.     

The diagnostic significance of specific serum IgA detection in cytomegalovirus infections

Summary The prevalence of virus-specific serum antibodies of IgA class against cytomegalovirus (CMV) was determined in 228 healthy blood donors and in 112 patients suspected of CMV infection. All patients had a titer of 40 or higher in the complement fixation test. Specific CMV-IgA was found in 81 per cent of CMV-IgM positive patient sera and in 20 per cent of sera from patients strongly suspected of CMV infection, but with negative CMV-IgM. Less than 2 per cent of healthy blood donors had CMV specific serum IgA.With 4 Figures     

Further studies on resistance toFasciola hepatica andEchinostoma revolutum in mice infected withSchistosoma sp.

Schistosoma sp. induced cross-resistance to a challenge withFasciola hepatica andEchinostoma revolutum was studied in mice. Primary patent 56-days-oldS. intercalatum andS. bovis infections stimulated a statistically significant level of resistance to a challenge withF. hepatica, and primary patent 100-day-oldS. bovis infections induced an almost complete resistance to a challenge withE. revolutum. Primary single-sexS. mansoni infections, either male or female, aged 90 days did not stimulate any resistance to a challenge withE. revolutum.A primary infection withS. mansoni aged 70 days induced a marked reduction (94.1–100%) in theE. revolutum worm recovery already 2 h post-challenge as compared with that of theE. revolutum challenge control group and complete elimination of the echinostome worm population inS. mansoni infected mice had taken place 24 h after challenge. E. revolutum worm populations established in mice harbouring newly patent 36-day-oldS. mansoni infections persisted unchanged for a period of at least 33 days into the patent period of the schistosome infection in spite of development of a complete resistance to a challenge withE. revolutum metacercariae during this period.     

Critical evaluation of medical, statistical, and occupational data sources in the Kola Peninsula of Russia pertinent to reproductive health studies

Background: The feasibility study described herein was prompted by a report in 1992 of possible reproductive and developmental health concerns among female workers in a Russian nickel refinery. Objective: The primary goal was to ascertain whether medical, statistical, and occupational data bases could be accessed for information about the pregnancy histories, occupational histories, and life-style factors of the women affected. Methods: The project was facilitated by construction of a registry of all births in three towns with a nickel refinery and verification of its contents against patients' records obtained from hospital delivery and gynecology departments and community polyclinics. Municipal Registration Board, Regional Health Statistics Board, and nickel company records were also reviewed. Results: Reproductive/developmental outcome information and workplace histories were acceptable. Sample-size calculations indicated that a cohort or cross-sectional study would be amenable and suitable for the detection of an excess risk for spontaneous abortion with adequate statistical significance and power. Such investigations would need to be supplemented by workplace environmental/biological monitoring assessments for evaluation of exposure to occupational hazardous factors and a worker's questionnaire to obtain information about life-style factors. A case-control design is recommended for the study of congenital defects. Conclusions: A well-designed, comprehensive epidemiology study is technically feasible because of the availability of a favorable pool of study subjects, reproductive/developmental outcome data, information to control for major confounders, and suitable occupational records. Received: 13 July 1998 / Accepted: 7 February 1999     

Pharmacokinetics of methyldopa in healthy man

Summary The pharmacokinetics of 2-¹⁴C-L--methyldopa have been investigated in five healthy volunteers following intravenous and oral administration. In the intravenous study a bi-phasic plasma concentration curve was found both for chemically determined -methyldopa and for radioactivity. The plasma level of radioactivity differed significantly from chemically determined drug, a pattern which was also found in urine. This suggests the presence of unidentified metabolite(s). The difference between plasma disappearance and urine recovery of -methyldopa and radioactivity during the first 4 h after injection suggests distribution to an extravascular compartment. Plasma half-lives of total radioactivity and of unchanged drug were calculated. In three subjects, pharmacokinetic parameters for a two-compartment open body model were calculated from urine and plasma data. Urinary recovery of radioactivity was almost complete within 48 h after intravenous administration. After oral administration, however, only about 40 per cent of the radioactive dose was recovered in the urine, and it contained approximately equal amounts of unconjugated methyldopa, acid-labile conjugated methyldopa and unidentified metabolite(s). The acid-labile conjugate was found only after oral administration, which supports the theory of a mucosal conjugation process. The lack of acid-labile conjugated drug either in the plasma or urine after intravenous injection indicates that there is no enterohepatic circulation of this drug.     

The Change in Retentive Values of Locator Attachments and Hader Clips over Time

Purpose: The aim of this study was to examine early changes in retentive values of implant overdenture attachments during multiple pulls.
Materials and Methods: Two implant attachment systems (Hader bar and clip, Locator system) were used in this study. The experimental groups were divided into yellow Hader clips, white Locator attachments, and green Locator attachments. Each group consisted of 21 matrix attachments. The attachments were placed into a custom-made acrylic resin block seated passively on another acrylic block containing a Hader bar or two Locator abutments with different angulations. Each attachment was subjected to 20 consecutive pulls using a universal testing machine. The peak load-to-dislodgement of the attachments after each pull was documented, and the percent reduction of the peak load-to-dislodgement was calculated. One-way ANOVA and Tukey's honestly significant difference test were used for data analyses. A p ≤ 0.05 was considered significant.
Results: There was a significant difference in the percent reduction in peak load-to-dislodgement between the attachments after the first pull ( p = 0.005) and after the final pull ( p = 0.0001). The yellow Hader clips exhibited the least percent reduction in peak load-to-dislodgement (6.50 ± 3.59%) after the first pull, followed by the white Locator attachments (8.60 ± 4.42%); the green Locator attachments exhibited the greatest reduction (11.05 ± 4.94%).
Conclusion: The results of this in vitro study demonstrate that retentive values of the Locator attachments are reduced significantly after multiple pulls. Although this reduction might not be noticeable to the patient, it is recommended that the clinician place and remove the overdenture multiple times before delivery.