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1.  Testing for bimodality in frequency distributions of data suggesting polymorphisms of drug metabolism--histograms and probit plots. 
1. The shape of histograms used to illustrate density distributions of indices of polymorphic drug metabolism was shown to be sensitive to the position of the cell divisions. 2. Non-linearity of the probit plot was shown not to indicate bimodality of the original density distribution. Computer simulation was used to generate examples of unimodal density distributions with curvilinear probit plots. 3. Using the same technique probit plots for bimodal density distributions were constructed. Some were shown to differ less from the probit plots of certain unimodal distributions than did the original density distributions. 4. The position of the antimode was shown not to coincide with inflections seen in the probit plots. 5. A new method for determining the linearity of probit plots is suggested.
PMCID: PMC1380035  PMID: 2611087
2.  Testing for bimodality in frequency distributions of data suggesting polymorphisms of drug metabolism--hypothesis testing. 
1. The theory of methods of hypothesis testing in relation to the detection of bimodality in density distributions is discussed. 2. Practical problems arising from these methods are outlined. 3. The power of three methods of hypothesis testing was compared using simulated data from bimodal distributions with varying separation between components. None of the methods could determine bimodality until the separation between components was 2 standard deviation units and could only do so reliably (greater than 90%) when the separation was as great as 4-6 standard deviation units. 4. The robustness of a parametric and a non-parametric method of hypothesis testing was compared using simulated unimodal distributions known to deviate markedly from normality. Both methods had a high frequency of falsely indicating bimodality with distributions where the components had markedly differing variances. 5. A further test of robustness using power transformation of data from a normal distribution showed that the algorithms could accurately determine unimodality only when the skew of the distribution was in the range 0-1.45.
PMCID: PMC1380036  PMID: 2611088
3.  Role of community pharmacies in prevention of AIDS among injecting drug misusers: findings of a survey in England and Wales. 
BMJ : British Medical Journal  1989;299(6707):1076-1079.
OBJECTIVE--To determine the current and potential roles of community pharmacists in the prevention of AIDS among misusers of injected drugs. DESIGN--Cross sectional postal survey of a one in four random sample of registered pharmacies in England and Wales. SETTING--Project conducted in the addiction research unit of the Institute of Psychiatry, London. SUBJECTS--2469 Community pharmacies in the 15 regional health authorities in England and Wales. MAIN OUTCOME MEASURES--Willingness of pharmacists to sell injecting equipment to known or suspected misusers of drugs; pharmacists' attitudes to syringe exchange schemes, keeping a "sharps" box for use by misusers of drugs, and offering face to face advice and leaflets; and opinions of community pharmacists on their role in AIDS prevention and drug misuse. RESULTS--1946 Questionnaires were returned, representing a response rate of 79%. This fell short of the target of one in four pharmacies in each family practitioner committee area in England and Wales, and total numbers of respondents were therefore weighted in inverse proportion to the response rate in each area. The findings disclosed a substantial demand for injecting equipment by drug misusers. After weighting of numbers of respondents an estimated 676 of 2434 pharmacies were currently selling injecting equipment and 65 of 2415 (3%) were participating in local syringe exchange schemes; only 94 of 2410 pharmacies (4%) had a sharps box for used equipment. There was a high degree of concern among pharmacists about particular consequences of drug misusers visiting their premises, along with a widespread acceptance that the community pharmacist had an important part to play. CONCLUSIONS--Promoting the participation of community pharmacists in the prevention of AIDS among misusers of injected drugs is a viable policy, but several problems would need to be overcome before it was implemented.
PMCID: PMC1837978  PMID: 2511969
4.  Timolol metabolism and debrisoquine oxidation polymorphism: a population study. 
1. The metabolism of orally administered timolol (T) to its ring cleavage ethanolamine (TE) and glycine (TG) products was studied in 108 unrelated hypertensive patients. 2. Statistically significant correlations between the 0-8 h urinary debrisoquine/4-hydroxy-debrisoquine ratio and the T/TE (rs = 0.74, P less than 0.001), T/TG (rs = 0.42, P less than 0.001) and T/TE + TG (rs = 0.49, P less than 0.001) ratios were found. 3. The log10 T/TE, T/TG and T/TE + TG ratios from poor metabolisers of debrisoquine (PMs) were grouped at the upper end of a unimodal distribution. 4. These results indicate that timolol metabolism is partly under monogenic control of the debrisoquine-type. 5. The mean +/- s.d. plasma timolol concentration in PMs (82 +/- 43 ng ml-1) was double that in extensive metabolisers (45 +/- 19 ng ml-1) (P = 0.011). The clinical significance of this observation remains to be established.
PMCID: PMC1379721  PMID: 2719899
6.  Dietary treatment of hyperlysinaemia. 
Archives of Disease in Childhood  1989;64(5):716-720.
We describe the lysine restricted, dietary management of three out of four siblings who were identified as having hyperlysinaemia. The diets, started in the neonatal period, were maintained for varying periods with unpredictable success. The propositus, who was not treated, was diagnosed at the age of 5 years, by which time he was already severely handicapped, presumably because of his metabolic disorder. Tentative recommendations are put forward for the management of this seemingly rare disorder. Mild chronic ammonia toxicity may be a factor in the pathogenesis of this condition.
PMCID: PMC1792052  PMID: 2499273
7.  Relationship between organization of the actin cytoskeleton and the cell cycle in normal and adenovirus-infected rat cells. 
Journal of Virology  1989;63(1):311-318.
Flow cytometry and staining with 7-nitrobenz-2-oxa-1,3-diazole-phallacidin were used to investigate organization of the actin cytoskeleton in rat embryo cells at different stages of normal and adenovirus E1A-induced cell cycles. In uninfected cells in G0-G1 and S phases, actin was predominantly in the form of stress fibers. In G2, this organization changed to peripheral rings of thin filaments, while during mitosis, actin had a diffuse distribution. Infection of quiescent rat cells by adenovirus caused them to enter the cell cycle and replicate DNA and also caused disruption of stress fibers. Rapid disappearance of stress fibers and the appearance of peripheral rings of actin filaments began from 13 h after infection and closely followed synthesis of the E1A proteins. Infected cells began S phase at about 24 h after infection, and cells in G2 and mitosis were seen from 30 to 50 h. Thus, disruption of the actin cytoskeleton is an early effect of E1A and not an indirect consequence of the entry of infected cells into the cell cycle.
PMCID: PMC247686  PMID: 2521186
8.  Functions of the two adenovirus early E1A proteins and their conserved domains in cell cycle alteration, actin reorganization, and gene activation in rat cells. 
Journal of Virology  1989;63(1):303-310.
Rat embryo cells were infected with adenovirus type 5 mutants that code for only one of the two early E1A proteins, mutants with defects in one of the two conserved regions common to the two proteins, or mutants with defects in the 46-amino-acid region unique to the 289-amino-acid E1A protein. Cells were scored for altered cell cycle progression, disruption of actin stress fibers, and activation of E2A expression. Mutants lacking either E1A protein were able to cause all of these effects; but mutants lacking a 243-amino-acid protein had less effect, and mutants lacking a 289-amino-acid protein much less effect, than wild-type virus. A mutation in any of the three conserved regions caused a defect in each E1A effect. To investigate the reported function of conserved domain 2 in mitosis, we monitored by fluorescence-activated cell sorter the reduction in Hoechst 33342 fluorescence that occurs when cells divide after undergoing a round of DNA replication in 5-bromodeoxyuridine. A smaller percentage of adenovirus-infected cells than mock-infected cells divided within a given period after completing a round of DNA replication. Viruses with mutations in conserved domain 2 were defective for initiation of cellular DNA replication, as were all other E1A mutants we have examined, but had no specific defect in cell division compared with wild-type virus. Thus, although there may be some specialization of function between the two E1A proteins and between their conserved domains, it was not apparent in the aspects of E1A function and the mutants that we examined.
PMCID: PMC247685  PMID: 2521185

Results 1-8 (8)