A comparison of dummy variable versus traditional multiple discriminant function analysis.

The authors compare the use of dummy variable and traditional multiple discriminant function analysis when dealing with research questions where ratio or nominal scale independent variables can be used. A healthcare-related example of using dv MDF is given and the authors conclude that it is superior to traditional MDF for determining variable importance and developing market segment profiles.     

Biological characteristics of newly diagnosed poor prognosis acute myelogenous leukemia

A pilot study was conducted of the biological characteristics of the leukemia cells of newly diagnosed patients with poor prognosis acute myelogenous leukemia (AML). This study included measurements of the pretherapy proliferative rate of the leukemia cells in vivo, assessment of differentiation in vivo during remission induction therapy, and the level of expression of the fms, myc, and IL1β genes in pretherapy leukemia cells. Short cell cycle times were characteristic of the best prognostic category and were associated with a rapid reduction in marrow leukemia cells in cytosine arabinoside (araC)-sensitive patients. Expression of c-fms was associated with rapid reduction in marrow leukemia cells during araC therapy and with a successful treatment outcome. Expression of the IL1β gene was associated with short remissions. These studies suggest that when compared to newly diagnosed standard prognosis AML, the leukemia of poor prognosis patients is more likely to exhibit long cell cycle times, low levels of fms expression, and is less likely to be associated with myeloid differentiation during remission induction therapy. © 1993 Wiley-Liss, Inc.     

The use of a low phenylalanine diet in response to the challenging behaviour of a man with untreated phenylketonuria and profound learning disabilities

If phenylketonuria (PKU) is not treated from an early age with a reduced phenylalanine diet, irreversible brain damage may occur. Although dietary intervention can do nothing to alter this impairment once it occurs, there is some evidence to suggest that a low phenylalanine diet may help to reduce the level of behavioural disturbances frequently experienced by people with untreated PKU. Using this evidence, dietary intervention was used in response to the challenging behaviour of a 30-year-old man with profound learning disabilities. Initial improvements were observed, but overall the results were inconclusive. Possible confounding factors are discussed. An unusual reaction to neuroleptic medication whilst on the diet is also documented.     

Signal transduction pathways involved in the acute potentiation of NMDA responses by 1S,3R-ACPD in rat hippocampal slices.

1. A grease-gap recording technique has been used to investigate the mechanisms underlying the acute potentiation of N-methyl-D-aspartate (NMDA) responses by aminocyclopentane-1S,3R-dicarboxylic acid (1S,3R-ACPD) in area CA1 of rat hippocampal slices. 2. 1S,3R-ACPD (10 microM), but not 1R,3S- ACPD (10 microM), potentiated submaximal responses to NMDA (dose-ratio of 0.81 +/- 0.02 (mean +/- s.e.mean); n = 55), but not to alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), in a readily reversible manner. Potentiation also occurred in slices treated with 0.2 microM tetrodotoxin, and in slices perfused with Mg(2+)-free medium. 3. 1S,3R-ACPD-induced potentiation was unaffected by the protein kinase inhibitors K-252b (0.1 microM) and staurosporine (1 microM) and the intracellular Ca2+ store depletor, thapsigargin (10 microM). Coapplication of staurosporine and thapsigargin was also without effect. 4. 1S,3R-ACPD-induced potentiation was unaffected by inhibitors of arachidonic acid formation, bromophenacyl bromide (50 microM) and RG80267 (100 microM). Arachidonic acid (10-50 microM) depressed reversibly NMDA-induced responses. The potentiation was unaffected by 8-bromo cyclic AMP (500 microM) or the PKA inhibitor Rp-adenosine 3,5-cyclic monophosphothioate triethylamine (Rp-cAMPS; 50 microM). 5. 1S,3R-ACPD-induced potentiation was abolished in slices perfused with Ca(2+)-free medium. The potentiation was also blocked by phorbol-12,13-diacetate (1 microM), in a staurosporine-sensitive manner. 6. It is concluded that the potentiation of NMDA responses by 1S,3R-ACPD is not mediated by protein kinase A or C, by release of Ca2+ from intracellular stores or by arachidonic acid.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changing antibiotic prescribing by educational marketing

A controlled cross-over study in 12 Victorian public hospitals was performed to examine the power of marketing techniques in influencing prescribing. The targeted prescribing behaviour was the use of antibiotic prophylaxis in surgery, and the criteria for judging the appropriateness of therapy were its duration and timing, as are detailed in the fourth edition of the booklet Antibiotic guidelines. The first intervention was mounted in 1985 in six hospitals (two metropolitan teaching hospitals, one suburban general hospital and three rural hospitals), and six matched hospitals acted as control hospitals. One year later, the intervention was mounted in the six hospitals that previously had been the control hospitals. The interventional campaign consisted of material that was similar to that which is used by the pharmaceutical industry, including an "academic" representative. Its effect was assessed by audits that were performed before and after the first interventional campaign and again, one year later, after the second interventional campaign. The proportion of antibiotic courses that were assessed as satisfactory in terms of duration increased significantly after the first campaign in the hospitals where the intervention was mounted. No significant changes in prescribing occurred in the control hospitals. In the hospitals which were control hospitals in 1985, and in which the intervention occurred in 1986, the proportion of antibiotic courses that were assessed as satisfactory also increased significantly after the interventional campaign. A fall-off in performance occurred during the 12 months after the campaign in the 1985-interventional hospitals. Calculated cost savings more than outweighed the costs of the campaign. We conclude that inappropriate prescribing behaviour in hospitals can be modified successfully by educational marketing techniques.     

The effects of carbamazepine on stuttering.

No pharmacological treatment protocol has proven generally useful for all patients who stutter. Various medications, behavior therapy, relaxation, suggestion, and social-based therapies have been used. For this drug treatment study, two groups of adult stutterers were followed in an 8-week open label protocol. All subjects had in the past received speech therapy; none had been treated previously with medication for stuttering. The first group (N = 12) received a maximum dose of 800 mg of carbamazepine; the second group (N = 8) received a maximum dose of 400 mg of carbamazepine. Each patient served as his or her own control. A series of systematic speech tests was given weekly to determine the variability of fluency for each subject. A statistically significant change occurred for a number of "expectancy to stutter" characteristics. Subjects felt that they stuttered less often while taking carbamazepine. Subjective effects began before medication and continued after patients discontinued the medication. Struggle characteristics also subjectively decreased. However, no objective improvement was found. No change was found in percentage of words stuttered, reading improvement, or improvement in spontaneous speech rate. Interrater reliability showed a correlation of .996. Three carbamazepine serum level therapeutic windows were inspected with negative results. Interestingly, naive listener ratings did show a statistically significant improvement on carbamazepine versus placebo. Future anecdotal reports of pharmacological improvement of stuttering should be subjected to rigorous objective testing before general acceptance.     

The contraceptive sponge: factors in initiation and discontinuation of use

This study examined characteristic of the contraceptive sponge that were important in women's decisions to use the contraceptive sponge and reasons why women discontinued sponge use. A sample of 385 current sponge users and 407 former sponge users participated in a national telephone survey on sponge use. Important reasons for trying the sponge were effectiveness, comfort, convenience and ease of use and it "would not interfere with sexual pleasure." The media and physicians were of considerable influence in women's decisions to initiate sponge use, but sexual partners, friends, parents and relatives exerted little influence. The most important reasons for discontinuing use of the sponge were pregnancy, both planned and accidental, and irritation, discomfort or vaginal infection. Women may decide to use the sponge because they have unrealistically positive perceptions of sponge characteristics.     

Seasonal prevalence of major congenital malformations in the Fylde of Lancashire 1957-1981.

The seasonal prevalence of major congenital malformations was studied in a prospective survey of 88,449 children born in the circumscribed Fylde of Lancashire to residents there over 25 years. Ascertainment was thought to be as complete as was practically possible because cases were recorded daily by one, and for 17 years the only, paediatrician and a very high rate of necropsies was maintained. The number of malformations were classified by month of maternal last menstrual period and seasonal variation was assessed by three statistical models. Neural tube defects showed a significant seasonal variation in month of last menstrual period but not in month of birth. From May 1956 to April 1968, when the prevalence of neural tube defects was high (5.5 per 1000 total births), conceptions were significantly more common in December to May. For anencephaly alone the figures were not significant, but spina bifida and cranium bifidum were more common in March to May. From May 1968 to April 1981, when the prevalence of neural tube defects fell below the national average, the significant variations disappeared. Seasonality for spina bifida and cranium bifidum was seen only in "singles" (cases with no other major lesion), but for anencephaly it was seen only in "multiples" (cases with other lesions). The three types of cardiac septal defect and persistent ductus each showed a higher prevalence of conceptions at some time during May to October. In contrast the commonest group of cyanotic cases showed no such pattern but with greater numbers in winter. There was evidence of a seasonal variation for bilateral renal agenesis and for vesicoureteric reflux as ascertained. Seasonal prevalence in an aetiological factor for certain malformations of the central nervous system, cardiac and urinary systems.     

Bioavailability of citrate from two different preparations of potassium citrate

The bioavailability of citrate from two different preparations of potassium citrate was examined in eighteen normal volunteers during three phases of study. After stabilization on a constant metabolic diet, subjects took a single dose of placebo, "slow-release" potassium citrate tablets (60 meq) or rapid-release liquid potassium citrate preparation (60 meq). Timed urine specimens were collected for 24 hours and analyzed for citrate, potassium, and pH. Similar biochemical findings were observed following administration of the two different preparations with the onset and decline of changes being slightly more rapid for the liquid potassium citrate than the tablet preparation. These equivalent bioavailability data indicate that the liquid preparation is a comparable therapeutic alternative to the tablet form.