Biomedical subjects

C J Walker

Publications and source records attributed to C J Walker.

At least 55 records · Page 3Linked to original sources

PubMed1987

Amiodarone for maintenance of sinus rhythm after conversion of atrial fibrillation in the setting of a dilated left atrium.

Previous reports suggest that the finding of left atrial (LA) dilatation (greater than 45 mm) by echocardiography identifies patients not likely to maintain sinus rhythm after conversion of atrial fibrillation (AF). However, these studies antedate the availability of amiodarone, an antiarrhythmic agent that reportedly is effective in patients with AF in whom other drug therapy has failed. To analyze the relation between LA size and the ability to maintain sinus rhythm with amiodarone therapy, 28 patients, aged 32 to 87 years (mean 61), with an LA dimension greater than 45 mm (range 46 to 78, mean 57) were studied. Thirteen patients (46%) had valvular heart disease, 10 (36%) dilated cardiomyopathy and 5 (18%) miscellaneous disorders. In 25 patients (89%) quinidine therapy had failed. After therapy with amiodarone, sinus rhythm returned in all patients and was maintained. Therapy was judged completely successful in 10 patients (alive and still in sinus rhythm with at least 1 year of follow-up), partially successful in 11 (maintaining sinus rhythm for at least 6 months before a change in status) and failed in 7. Completely successful therapy was accomplished in 9 of 18 patients with an LA dimension between 46 and 60 mm, but in only 1 of 10 patients with an LA dimension greater than 60 mm (p less than 0.05). Thus, patients with LA dimensions between 46 and 60 mm who are significantly compromised by AF can often be maintained in sinus rhythm with amiodarone therapy. However, in patients with larger LA dimensions. AF is likely to return despite aggressive antiarrhythmic therapy with amiodarone, a drug with potentially serious side effects.

Adult↗

PubMed1987

Planning for the information age: a survey of microcomputer use in a faculty of health sciences.

Microcomputers can greatly enhance information processing by clinicians and improve the quality of health care. We surveyed 983 full- and part-time faculty members to assess the state of microcomputer use in the Faculty of Health Sciences at McMaster University, Hamilton, Ont. The ratio of faculty members to microcomputers was close to 1; however, 29% of the full-time and 52% of the part-time members who responded indicated that they did not use a computer. Among those who did, the range of applications was generally limited. There was no mention of more advanced uses such as diagnosis, treatment and patient records. Only about 30% of the respondents had taken a computer course, but all indicated a desire to take courses (on average, three of the seven listed in the questionnaire). Our results showed an extensive but unequal distribution of microcomputers and revealed the need for planning and education to put them to optimal use.

Computers↗

PubMed1987

The relation of forearm mineral density to peripheral fractures in postmenopausal women.

Forearm bone mineral density was measured in 557 postmenopausal women from whom a history of fractures was also obtained. Known cases of osteoporosis were excluded. The mean age of the subjects was 59 years. Ninety-eight of the subjects had sustained a fracture since the menopause and 37 had done so before the menopause. There had been 188 fractures in all. The mean bone density was significantly lower in the subjects who had experienced a fracture than in those who had not experienced a fracture; this was also true of subjects who had suffered a fracture before the menopause. The lowest bone densities were observed in subjects who had suffered forearm fractures, followed by those who had suffered fractures of the rib, ankle and foot. The mean bone density in subjects with more than one fracture was significantly lower than in those with only one fracture. The difference in bone density between subjects with and without a history of fractures was most significant in the younger subjects and became progressively less significant with age. The estimated relative fracture risk was 3.1 in the group with the lowest bone densities and zero in the group with the highest bone densities.

Female↗

PubMed1987

Effect of calcium supplementation on forearm bone mineral content in postmenopausal women: a prospective, sequential controlled trial.

Three hundred ten normal postmenopausal volunteers were invited to enter a controlled trial of the effects of calcium supplementation on forearm mineral content (FMC); 269 entered the study and 210 completed it. Of those who completed the study, 158 were allocated to one of three calcium-supplemented treatment regimes and 52 were allocated to a control group. Twenty-two of the subjects allocated to the treatment group were unable to take supplementary calcium but agreed to remain in the study as additional controls. There were therefore 136 treated subjects, 52 strict controls and 74 controls altogether. During the initial observation period of 9 mo, there was a highly significant loss of bone in all groups (P less than 0.001). During the 9-mo period of treatment, there was a highly significant reduction in the rate of bone loss in the treated subjects (P less than 0.001), a just significant reduction in the strict controls (P less than 0.05) and a nonsignificant reduction in the rate of loss in all controls. The difference between the treated and strict controls in the second period was not significant but the difference between the treated and all controls in the second period was significant (P less than 0.025). When the analysis was applied only to women within 10 yr of menopause, the difference between the treated and strict control groups in period 2 was significant (P less than 0.025) and the difference between the treated and all controls was highly significant (P less than 0.001).

Bone and Bones↗

PubMed1987

Computer-aided quality assurance. A critical appraisal.

Computerized information systems hold the promise of overcoming problems in the management of clinical information Many of the claims of the creators and promoters of these systems, however, are not based on sound clinical studies. To determine the ability of computer information systems to improve the quality of medical care, we applied methodologic criteria to published articles in the field. Only 30 (22%) of 135 articles reported preplanned investigations, and only half of these met minimal criteria for scientific investigations. Fourteen studies were well designed and executed. All studies reported improvements in the process of care. However, patient outcomes were not measured, not affected, or only minimally influenced. While computer information systems show increasing potential, more work is required to enhance their effect on the quality of care and thus on patient outcomes.

Evaluation Studies as Topic↗

PubMed1987

Effects of nandrolone therapy on forearm bone mineral content in osteoporosis.

Forearm bone mineral content (BMC) was measured sequentially on and off anabolic steroid therapy in 52 postmenopausal women with osteoporosis. The steroid used was nandrolone decanoate in a dose of 50 mg every two weeks by intramuscular injection. In 16 of the patients nandrolone was given first (for 6.2 +/- 0.6 months) followed by a control period (6.1 +/- 1.0 months) and in 36 there was an initial control period (9.5 +/- 1.1 months) followed by nandrolone (for 5.8 +/- 0.4 months). Any other therapy was continued unchanged during both treatment and control periods. There was a significant rise in BMC on nandrolone (p less than 0.001) and a nonsignificant fall in BMC off nandrolone. The difference between the rates of change on and off nandrolone was highly significant (+53 vs. -7 mg/cm/year; p less than 0.001).

Aged↗

PubMed1986

Comparison of calcium, calcitriol, ovarian hormones and nandrolone in the treatment of osteoporosis.

Most therapy for osteoporosis has been aimed at decreasing bone resorption and is capable of preventing further bone loss. Recently, anabolic steroids have been claimed to cause increased bone mass in osteoporosis, but the mechanism for this effect is not understood. In this study calcium, and calcium with calcitriol, caused a slowing of forearm bone mineral loss. Calcium and ovarian hormones, with or without calcitriol, caused a small non-significant rise in forearm mineral density, and nandrolone decanoate 50 mg intramuscularly, every 2 or 3 weeks caused a significant rise in forearm mineral density (+15.9 +/- 2.4 mg/ml/yr and +13.7 +/- 3.4 mg/ml/yr, respectively). The 3-weekly regime caused few side effects and is considered the optimal dose. The striking rise in bone density in patients in whom bone resorption was controlled before therapy, suggests that anabolic steroids can increase the bone formation rate.

Aged↗

PubMed1986

How to keep up with the medical literature: I. Why try to keep up and how to get started.

Patient care is often outmoded because physicians lack awareness about important advances in medical knowledge. According to physicians, reading journals is the most popular method for staying informed, but the great volume of journal literature precludes clinicians' from reading all of it. In this first of six articles on keeping up with the medical literature, we describe three strategies to enhance the efficiency and effectiveness of journal reading. First, priority should be given to reading original articles concerning reports of planned investigations because only these articles provide sufficient details to assess the relevance, validity, and clinical application of new knowledge. Second, reading should be restricted to articles of direct pertinence to one's clinical practice. Third, the methods section of articles should be quickly screened first to select studies that have used sufficiently high standards to warrant clinical action based on study results.

Education, Medical, Continuing↗

PubMed1986

How to keep up with the medical literature: II. Deciding which journals to read regularly.

For practitioners, one of the major objectives for reading the medical literature is to maintain clinical competence. Ideally, this task is accomplished through efficiently extracting from the literature properly validated advances in medical knowledge of direct relevance to the reader's own practice. Practically, the extraction process is a difficult one because reports describing such advances are disseminated through a multitude of general and specialty journals. We describe a preemptive strategy for clinicians to determine which journals to read on a regular basis. General and specialty journals of potential relevance to the reader's practice should be selected initially on the basis of circulation or citation impact, and then consecutive issues surveyed to determine the journals' yields of articles that are both directly relevant and of high quality. Subsequent reading should concentrate on the journals that produce the highest yield on this personal survey.

Clinical Competence↗

PubMed1986

How to keep up with the medical literature: III. Expanding the number of journals you read regularly.

Clinicians can derive immense satisfaction from keeping abreast of new developments in patient care by regularly scanning the medical journal literature. Combined with good reading habits and self-discipline, this scanning generally can be accomplished within the time that most practitioners allot to attempting to keep up to date. We describe tactics for formulating a personalized journal-reading list and ensuring access to the key articles in one's field at a reasonable cost. These tactics begin with deleting low-yield journals from regular reading and adding journals more relevant to one's interests. The cost of multiple journal subscriptions can be reduced by circulating different journals among colleagues or by regular visits to the library. These tactics can be supplemented or replaced by using Current Contents or the Selective Dissemination of Information service of the National Library of Medicine and other database vendors.

Education, Medical, Continuing↗

PubMed1986

How to keep up with the medical literature: IV. Using the literature to solve clinical problems.

Ideally, searches for published articles to solve clinical problems should lead to the best evidence on a given topic quickly and at reasonable expense. This goal can be achieved with modern information skills, sources, and services. In this article, we describe and compare various means, from textbooks to computers, that provide access to information of potential value in addressing clinical problems as they arise. Using the problem of understanding and controlling the risk for the acquired immunodeficiency syndrome among personnel of a community hospital, we examined the following sources for their utility in locating journal literature: general and specialty medical texts, personal reprint collections, expert clinicians, recent journal issues, library textbook collections, the Index Medicus "Bibliography of Reviews" and subject index, and MEDLINE computer searching. For this problem, Index Medicus and MEDLINE were the best sources of up-to-date articles, but MEDLINE was three times as fast.

Information Services↗

PubMed1986

How to keep up with the medical literature: V. Access by personal computer to the medical literature.

Access to the medical literature through personal computers is now readily available and can greatly reduce logistical barriers to using recently published journal articles to support clinical decisions. In this article, we describe many of the options available to clinicians who wish to do their own computer searching of MEDLINE, the largest of the electronic services for the biomedical literature. The "bare bones" computer equipment needed includes a terminal or personal computer, a modern and telephone line, and a printer. Access to MEDLINE is then gained through subscribing to any of a burgeoning number of database vendors. A comparison of 17 permutations and combinations of software and vendors shows that the software and vendors vary substantially in efficiency, cost, and ease of use. Direct subscription to MEDLINE is least expensive, PaperChase is the simplest service to use, and Colleague and Medis provide both MEDLINE access plus full-text journals online. Basic search techniques are illustrated for three clinical problems.

Computers↗

PubMed1986

How to keep up with the medical literature: VI. How to store and retrieve articles worth keeping.

The human mind is not well suited to storing and retrieving large amounts of infrequently used information. An effective personal filing system is needed if good articles that we encounter in our efforts to keep up to date are to be kept handy for future reference. Many options exist for the creation of a personal filing system. In this article, we assist the reader in the development of a tailor-made system that is based on making key decisions that strike a balance between filing needs and the lack of enthusiasm that most of us have for filing. The complexity of the system should match the number of purposes that your file must serve. Important additional considerations include how much time and effort you are willing to spend; where and how you will house your collection; how many articles you want to keep in the file; what standards you will apply in selecting material for your file; what subject headings are most appropriate for your articles; whether you will need to cross-reference; and what access you will have to personal computers.

Abstracting and Indexing↗

PubMed1986

Forearm bone mineral content does not decline with age in premenopausal women.

Forearm densitometry was performed on 77 normal premenopausal women aged 22-59 years. Bone mineral content (BMC) (arbitrary units) was converted into true forearm mineral content (FMC) (mg/cm) by measuring and ashing a sample radius and ulna. FMC was divided by width to yield surface density (mg/cm2) and divided by cross-sectional area to yield forearm mineral density (FMD) (mg/ml). The coefficient of variation of FMC was 12.3%, which was reduced to 10.1% after correction for width and 10.9% after correction for area. FMC was significantly related to height, bone width, and bone area but not to weight. The correlation with height was lost when FMC was corrected for bone width or bone area. None of the measured or derived bone variables was significantly related to age. Neither total bone mass nor bone density declines with age in premenopausal women. A comparison of normal and osteoporotic women will be required to establish whether bone width or bone area is the best referent for forearm mineral content.

Adult↗

PubMed1985

Computer searching of the medical literature. An evaluation of MEDLINE searching systems.

Although clinicians can now search the medical literature electronically from the clinic, bedside, or operating suite, little is known about the performance characteristics of online information services. Fourteen access routes to the MEDLINE database of journal literature were compared for retrieval quantity and quality, user and online search time, and cost for randomly ordered, standardized searches on common clinical problems. All routes produced the articles we judged to be the most definitive on the clinical problem. However, routes differed significantly (p less than 0.01) for the same searches with respect to online time (range, 5.15 to 18.72 minutes), total search time (8.37 to 20.55 minutes), cost (US $3.38 to $11.62), and proportion of articles relevant to the topic (98% to 75%). "User friendliness" aside, our results showed that the higher the cost, the worse the product. Clinicians should consider these major differences when deciding which search system to use.

Costs and Cost Analysis↗

PubMed1983

The management of pancreatic carcinoma: a review of 173 cases.

Pancreatic carcinoma is an increasingly common malignancy, cure of which is rarely feasible. Ideal management involves the safe and effective palliation of symptoms once the diagnosis has been established beyond reasonable doubt and the unlikely possibility of cure by radical surgery ruled out. In this retrospective study of 173 patients, management fell short of the ideal. Histological confirmation of the diagnosis was obtained in only 42% of patients, and there was a 16% reoperation rate because of the failure of an initial palliative procedure to relieve actual or potential biliary or gastric outlet obstruction. Still more patients developed recurrent obstructive jaundice or duodenal obstruction but did not undergo further surgery. To achieve optimal palliation, it is recommended that a gastroenterostomy be performed whenever a palliative operation is undertaken for the relief of obstructive jaundice, and that biliary drainage be accomplished by anastomosis of bowel to the common hepatic duct rather than the gall-bladder whenever possible, to minimize the risk of recurrent obstruction. It is further recommended that an attempt be made to obtain a tissue diagnosis in every case, since other methods of diagnosis are unreliable.

Adult↗

PubMed1983

Treatment and prognosis in congenital club foot.

One hundred and twenty-nine unselected club feet were classified at birth into three grades of severity; 123 were followed up. The results of primary treatment were analysed and it is shown that the bad feet did worst. Serial splinting in plasters achieved lasting correction in nine in ten mild club feet, in half of the moderately deformed, but in only one in ten of the severely affected. Surgical correction succeeded in two out of three of the resistant feet, but had to be repeated in the others.

Casts, Surgical↗

PubMed1975

Value of Doppler ultrasound in diagnosis of clinically suspected deep vein thrombosis.

Doppler ultrasound was used to study 120 legs of 106 patients with suspected deep vein thrombosis (DVT) or pulmonary embolism. Venography was subsequently performed in all. DVT was confirmed by venography in 44 legs and was confined to the calf in 10 of these. Ultrasound detected three calf thromboses and 29 out of 34 more extensive thromboses. Of five undetected thrombi that were proximal to the calf one was associated with partial occlusion and four with extensive collateral circulation. Of the 76 limbs without venographic evidence of thrombosis 21 were thought to have DVT by ultrasound; 18 of these false-positive results could be attributed to external compression of veins, two to excessive tenderness precluding adequate examination; and in one no explanation was found. This test gives more accurate results than judging by clinical signs alone, but users must be aware of its limitations and, particularly, the causes of false-positive and false-negative results.

Doppler Effect↗