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Biomedical subjects

R MacDonald

Publications and source records attributed to R MacDonald.

At least 55 records · Page 3Linked to original sources
PubMed1999

beta-sitosterol for the treatment of benign prostatic hyperplasia: a systematic review.

OBJECTIVES: To conduct a systematic review of the evidence for the efficacy of beta-sitosterol in men with symptomatic benign prostatic hyperplasia (BPH). METHODS: Studies were identified through Medlinetrade mark (1966-98), EMBASEtrade mark, Phytodok, the Cochrane Library, bibliographies of identified trials and review articles, and contact with study authors and pharmaceutical companies. Randomized trials were included if: men had symptomatic BPH; plant extract preparations contained beta-sitosterols; a control group received placebo or a pharmacological therapy; and treatment duration was >/=30 days. Study characteristics, demographic information, enrolment criteria and outcomes were extracted. RESULTS: Four trials comprising a total of 519 men met the inclusion criteria. All were double-blind and lasted 4-26 weeks. Three studies used nonglucosidic beta-sitosterols and one used a preparation that contained only beta-sitosterol-beta-d-glucoside. Compared with placebo, beta-sitosterol improved urinary symptom scores and flow measures. For the two studies reporting the International Prostate Symptom Score (IPSS), the weighted mean difference (WMD) against placebo was -4.9 IPSS points (95% confidence interval, CI,-6.3 to-3.5). The WMD for peak urinary flow rate was 3.91 mL/s (95% CI 0.91 to 6.90, four studies) and for residual volume the WMD was -28.62 mL (95% CI-41.42 to-15.83, four studies). beta-sitosterol did not reduce prostate size. The trial using pure beta-sitosterol-beta-d-glucoside (WA184) showed no improvement in urinary flow measures. Withdrawal rates for men assigned to beta-sitosterol and placebo were 7.8% and 8.0% (not significant), respectively. CONCLUSION: beta-sitosterol improves urological symptoms and flow measures. However, the existing studies are limited by short treatment duration and lack of standardized beta-sitosterol preparations. Their long-term effectiveness, safety and ability to prevent the complications of BPH are unknown.

Adult↗
PubMed1998

A novel approach to tracheostomal collapse: the use of an endoluminal Palmaz stent.

There are a number of surgical treatments for tracheostomal collapse of the pediatric airway. The techniques include tracheoplasty with costal cartilage graft, the placement of a tracheostomy tube and partial tracheal resection and primary tracheal anastomosis to name a few. Since each child may possess unique medical and social factors in additional to the tracheal pathology, the surgical approach must be individualized. A case history of a 1-year-old Vietnamese child with a tracheostomal collapse is presented. In this case, an endoluminal Palmaz stent was placed endoscopically to support the collapsed tracheal segment for 3 months. After 3 months, the stent was removed, and the child has done well without any airway intervention for 2 years. The indications for this novel approach, the technique of insertion and removal of the stent are the focus of this paper.

Humans↗
PubMed1998

Saw palmetto extracts for treatment of benign prostatic hyperplasia: a systematic review.

OBJECTIVE: To conduct a systematic review and, where possible, quantitative meta-analysis of the existing evidence regarding the therapeutic efficacy and safety of the saw palmetto plant extract, Serenoa repens, in men with symptomatic benign prostatic hyperplasia (BPH). DATA SOURCES: Studies were identified through the search of MEDLINE (1966-1997), EMBASE, Phytodok, the Cochrane Library, bibliographies of identified trials and review articles, and contact with relevant authors and drug companies. STUDY SELECTION: Randomized trials were included if participants had symptomatic BPH, the intervention was a preparation of S repens alone or in combination with other phytotherapeutic agents, a control group received placebo or other pharmacological therapies for BPH, and the treatment duration was at least 30 days. DATA EXTRACTION: Two investigators for each article (T.J.W., A.I., G.S., and R.M.) independently extracted key data on design features, subject characteristics, therapy allocation, and outcomes of the studies. DATA SYNTHESIS: A total of 18 randomized controlled trials involving 2939 men met inclusion criteria and were analyzed. Many studies did not report results in a method that permitted meta-analysis. Treatment allocation concealment was adequate in 9 studies; 16 were double-blinded. The mean study duration was 9 weeks (range, 4-48 weeks). As compared with men receiving placebo, men treated with S repens had decreased urinary tract symptom scores (weighted mean difference [WMD], -1.41 points [scale range, 0-19] [95% confidence interval (CI), -2.52 to -0.30] [n = 1 study]), nocturia (WMD, -0.76 times per evening [95% CI, -1.22 to -0.32] [n = 10 studies]), and improvement in self-rating of urinary tract symptoms; risk ratio for improvement (1.72 [95% CI, 1.21-2.44] [n = 6 studies]), and peak urine flow (WMD, 1.93 mL/s [95% CI, 0.72-3.14] [n = 8 studies]). Compared with men receiving finasteride, men treated with S repens had similar improvements in urinary tract symptom scores (WMD, 0.37 International Prostate Symptom Score points [scale range, 0-35] [95% CI, -0.45 to 1.19] [n = 2 studies]) and peak urine flow (WMD, -0.74 mL/s [95% CI, -1.66 to 0.18] [n = 2 studies]). Adverse effects due to S repens were mild and infrequent; erectile dysfunction was more frequent with finasteride (4.9%) than with S repens (1.1%; P<.001). Withdrawal rates in men assigned to placebo, S repens, or finasteride were 7%, 9%, and 11%, respectively. CONCLUSIONS: The existing literature on S repens for treatment of BPH is limited in terms of the short duration of studies and variability in study design, use of phytotherapeutic preparations, and reports of outcomes. However, the evidence suggests that S repens improves urologic symptoms and flow measures. Compared with finasteride, S repens produces similar improvement in urinary tract symptoms and urinary flow and was associated with fewer adverse treatment events. Further research is needed using standardized preparations of S repens to determine its long-term effectiveness and ability to prevent BPH complications.

Enzyme Inhibitors↗
PubMed1998

Magnitude, duration, quality, and function of pneumococcal vaccine responses in elderly adults.

The suboptimal efficacy of the currently available 23-valent pneumococcal vaccine in the growing population of adults >65 years old may be related to the limited immunogenicity of the vaccine polysaccharides in this group. In this study, the majority of elderly outpatients with stable chronic illnesses generated a vigorous IgG response to seven vaccine serotypes comparable to that of healthy young adults at 1, 3, and 16 months after immunization. Moreover, the quality and function of anticapsular antibodies, measured as avidity and in vitro opsonization, were comparable between elderly and young subjects over time. However, a subset (approximately 20%) of elderly outpatients responded to fewer than two of seven serotypes tested 1 and 3 months after immunization, whereas none of the healthy young adults were such poor responders. Thus, despite the adequate mean immune responses of the elderly as a group, a substantial proportion of elderly persons may have poor responses to the currently available pneumococcal vaccine.

Adult↗
PubMed1997

Characterization of pBP614, a putative rolling-circle plasmid from Bacillus popilliae.

A plasmid, pBP614 (5.647 kb), has been isolated from the New Zealand Bacillus popilliae strain 17 and characterized by physical mapping, cloning, and sequencing. An open reading frame was found which could encode a protein with homology to the replication (Rep) proteins of rolling-circle plasmids. The predicted B. popilliae Rep protein shows closest homology to Rep proteins from Bacillus plasmids of the pC194 family. Sequences homologous to plus- and minus-strand replication origins were found. The minus-strand origin shows similarities to the pal-T type family. Taken together, these observations suggest that pBP614 is a rolling-circle plasmid, the first such plasmid characterized from B. popilliae.

Amino Acid Sequence↗
PubMed1997

Side effects associated with pneumococcal vaccination.

BACKGROUND: Pneumococcal disease is a major cause of morbidity and death, especially among elders and other people at high risk. In spite of long-standing national recommendations for its use, pneumococcal vaccine is underused, with 70% or more of targeted persons as yet unimmunized. Concern about side effects is a barrier to successful vaccine delivery. METHODS: Persons attending a walk-in pneumococcal vaccination clinic were surveyed by use of structured telephone interviews. They were asked about health characteristics and local and systemic symptoms experienced during the week after their vaccination (postvaccination period). These responses were compared with the symptoms they reported for the 7 days immediately preceding their interview (the comparison period). RESULTS: A total of 1006 persons were interviewed a mean of 65.4 days after their vaccination. They had an average age of 69.9 years, and approximately 95% were in a high-risk group targeted for pneumococcal vaccination. For all systemic symptoms including fever, rash, myalgias, fatigue, malaise, and headache, subjects reported similar or lower rates during the postvaccination week than during the comparison week. Local reactions occurred in 28.2% of subjects. These local symptoms were mild to moderate for more than 90% of subjects and rarely resulted in the need to decrease the use of their arm. CONCLUSION: Pneumococcal vaccination was not associated with an increase in systemic symptoms but was associated with mild to moderate local symptoms in about one fourth of vaccine recipients. These findings should help health care providers and their patients address an important barrier to pneumococcal immunization.

Aged↗