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Biomedical subjects

S A McLean

Publications and source records attributed to S A McLean.

At least 19 recordsLinked to original sources
PubMed2001

The impact of changes in HCFA documentation requirements on academic emergency medicine: results of a physician survey.

BACKGROUND: The Health Care Financing Administration (HCFA) has dramatically increased documentation and procedural supervision required by faculty in academic emergency departments (EDs). OBJECTIVES: To determine academic emergency medicine (EM) physicians' perceptions of the impact of HCFA documentation requirements (HDR) on teaching time, clinical efficiency, and job satisfaction. METHODS: An observational cross-sectional study was done using a survey of New England academic EM faculty from September to December 1999. E-mail surveys were followed by hard copy to nonresponders. Teaching time, clinical efficiency, and job satisfaction were rated on a five-point Likert scale. Yes/no questions about other possible benefits of HCFA regulations were asked. Frequency (95% CI) and chi-square analyses were performed. RESULTS: One hundred seventy-four of 233 (75%) responded. Eighty-nine percent (95% CI = 84% to 93%) of the respondents thought teaching time was somewhat or markedly decreased by changes in HDR (somewhat 46%, markedly 43%). Seventy-nine percent (95% CI = 73% to 85%) believed clinical efficiency was somewhat or markedly decreased by changes in HDR (somewhat 49%, markedly 30%). Eighty percent (95% CI = 73% to 86%) reported somewhat or markedly decreased job satisfaction due to changes in HDR (somewhat 56%, markedly 24%). Twenty-one percent (95% CI = 15% to 27%) believed changes in HDR had improved patient care by requiring increased patient supervision. Forty-eight percent (95% CI = 40% to 56%) thought that changes in documentation requirements had decreased medicolegal risk by improving patient documentation. CONCLUSIONS: Most academic EM physicians in New England perceive that HDR have decreased clinical efficiency, teaching time, and job satisfaction. These findings suggest that changes in HDR may have a substantial impact on many different aspects of emergency care provided in academic settings.

Academic Medical Centers↗
PubMed2000

Lidocaine-induced conduction disturbance in patients with systemic hyperkalemia.

We report 2 cases in which lidocaine, given for wide-complex tachycardia in the presence of hyperkalemia, precipitated profound conduction disturbance and asystole. The electrophysiologic effects of hyperkalemia and its interaction with lidocaine are reviewed. In patients with known hyperkalemia and wide-complex tachycardia, treatment should be directed at hyperkalemia, rather than following treatment algorithms for wide-complex tachycardia.

Adult↗
PubMed1999

Loop electrosurgical excision procedure for partial upper vaginectomy.

OBJECTIVES: Partial upper vaginectomy consists of removal of the vaginal apex and is indicated for the diagnosis and treatment of vaginal intraepithelial neoplasia and recurrent cancer. We present a novel surgical approach to partial upper vaginectomy by use of the loop electrosurgical excision procedure. STUDY DESIGN: A total of 15 consecutive patients with abnormal vaginal cytologic results were treated by the loop electrosurgical excision procedure for partial upper vaginectomy. After submucosal injection of local anesthetic, the loop electrode was used to resect the upper third of the vagina. An iodoform vaginal pack was placed for 24 hours. All patients with high-grade vaginal intraepithelial neoplasia received intravaginal 5-fluorouracil cream postoperatively. RESULTS: The mean blood loss was 0 mL, and the mean surgical time was 30 minutes. A complication developed in 1 patient (7%). One case of invasive carcinoma was diagnosed. No recurrences have developed in any patients with vaginal intraepithelial neoplasia after hysterectomy. CONCLUSIONS: The loop electrosurgical excision procedure for partial upper vaginectomy can be performed quickly, with minimal blood loss, minimal complications, and minimal recurrence of neoplasia, and it provides a histologic specimen for evaluation.

Adult↗
PubMed1999

Legal and ethical aspects of the vegetative state.

The diagnosis of persistent or permanent vegetative state (PVS) raises ethical and legal problems. Strict adherence to the doctrine of the sanctity of life would require carers to continue to maintain the individual, perhaps for many years. However, few would regard this as an appropriate outcome when the person clearly has no capacity to interact with the environment and has no likelihood of recovery. However, the ethical and legal commitment to the sanctity of life has led courts to employ a variety of approaches to this situation in order to find a way in which the person in PVS can be allowed to die. It is argued that each of the approaches is disingenuous and ultimately unhelpful. What the law is doing is endorsing non-voluntary euthanasia, but dressing it up as something else. This is unhelpful for all concerned and the time has come for a review of all end of life decisions so that doctors, patients, and relatives can make honest decisions without fear of legal reprisal.

Ethics, Medical↗
PubMed1994

Mapping the human genome--friend or foe?

The Human Genome Project represents one of science's most significant advances. It offers to individuals and communities the capacity to make informed and autonomous decisions. However, it also poses fundamental questions which, it is argued, should be in contemplation now. If mechanisms for the resolution of these issues are not in place before the conclusion of the project, and are not available to guide and control its progress, individual privacy may be seriously affected. Employers, insurers and many other groups may seek access to information which would otherwise be confidential to the individual; families may be torn apart by the information held by one member in respect of the collective gene pool of the family unit. The law has a key role to play in encouraging the sensible use of this information, whilst at the same time protecting individuals and their rights.

Confidentiality↗
PubMed1993

Antigenic variants of Plasmodium chabaudi chabaudi AS and the effects of mosquito transmission.

Previous results, using a passive transfer assay, have shown that recrudescences of Plasmodium chabaudi chabaudi AS strain are antigenically different from the infecting parental population and also that the recrudescence appears to be a mix of antigenic types. This present study examines further these recrudescent populations using an indirect fluorescent antibody test on live, schizont-infected red blood cells. This analysis shows that ten clones derived from a recrudescence are all antigenically different from the parent population and that some are different from each other. The use of this method to examine the antigenic types of recrudescent clones after transmission through mosquitoes also demonstrates a resulting change in antigenicity. Such results showing a link between mosquito transmission and varying antigenicity may have important implications in terms of immunity and vaccine development.

Animals↗
PubMed1990

Early appearance of variant parasites in Plasmodium chabaudi infections.

Previous studies have shown that the recrudescence parasitaemias seen in mice infected with Plasmodium chabaudi AS strain are antigenically different from the infecting parent population. Antigenic differences between recrudescent and parent populations were demonstrated in a passive transfer assay. In the present study, using the same assay system, it has been shown that in some mice, variant parasites (i.e. different from the parent population) can be detected at a time when the primary parasitaemia is still patent but in remission. This is the first report in Plasmodium of variant parasites being detected during the course of a patent primary parasitaemic episode of an infection initiated with a cloned line.

Animals↗
PubMed1989

Host diet in experimental rodent malaria: a variable which can compromise experimental design and interpretation.

Over the past few years several experienced groups studying malaria have encountered significant problems with their particular rodent malaria-host system. This has involved, in some cases, periods during which the recovery of cryopreserved parasite stocks and growth of bloodstream parasites was markedly inhibited and, in other cases, periods of drastically increased mortality rates. The common factor linking these incidents was that they coincided with alterations in the experimental animal diet used. The inhibition of growth of cryopreserved stabilates or bloodstream parasites was abolished by supplementation with p-aminobenzoic acid (PABA) or by changing the diet used. Although the suppressive effects of diets lacking PABA on parasite growth have been known for over 30 years, the variation of PABA levels in modern laboratory animal feed concentrates is not well recognized. We have not established the exact cause of increased mortality, but it has been overcome by changing the diet used. We are documenting our experiences with this potential variable to forewarn workers in other laboratories of possible problems inherent in the use of different diets.

4-Aminobenzoic Acid↗
PubMed1987

The effect of mosquito transmission of antigenic variants of Plasmodium chabaudi.

Plasmodium chabaudi AS strain in mice is characterized by an acute primary parasitaemia, and one or more less acute recrudescences. Previous work has shown, using a passive protection assay, that the recrudescent parasites are usually antigenically different from parasites of the parent population with which the mice were first infected. In this study the effect of mosquito transmission on the antigenic expression of recrudescent populations of P. chabaudi was examined. In the first experiments the recrudescent population which was antigenically different from the parent population was uncloned. After transmission through Anopheles stephensi the recrudescent population appeared to revert to an antigenic type similar to that of the parent population. In the second experiment clones from a recrudescent population were mosquito transmitted and again the parasites of the primary patent parasitaemia in the mice, bitten by the infected mosquitoes, had reverted to the parental type. It is suggested that antigenic variants of P. chabaudi AS strain may revert to a basic type after mosquito transmission.

Animals↗
PubMed1987

Antigenic diversity in Babesia divergens: preliminary results with three monoclonal antibodies to the rat-adapted strain.

Three murine monoclonal antibodies were raised against the rat-adapted strain of Babesia divergens. In the indirect fluorescent antibody test (IFAT) the monoclonals did not react with B microti or B bovis. The monoclonals in IFAT gave high titres with the rat-adapted strain of B divergens, but showed variable reactivity with field isolates of the parasite indicating antigenic diversity in this parasite. Two of the monoclonals, as ascitic fluid, were protective against the rat-adapted strain in splenectomised rats.

Animals↗
PubMed1986

Antigenic variation in Plasmodium chabaudi: analysis of parent and variant populations by cloning.

Nineteen of 22 recrudescent populations of Plasmodium chabaudi AS strain were found to be significantly less sensitive to the protective activity of pools of immune serum, than the parent population from which they were derived. The immune sera were collected from donor mice which had been infected with the parent population and had just reduced the patent primary parasitaemia to subpatent levels. Clones prepared from the parent population (which had previously been cloned) and recrudescent variant populations were tested for their sensitivity to the immune sera. It was found that all the clones from the parent population were sensitive to the immune sera but some were more sensitive than others and that a recrudescent variant population could include both sensitive and insensitive parasites. Two insensitive clones of the recrudescent population were found to be different from each other.

Animals↗
PubMed1984

Consent, dissent, cement.

The patient-doctor relationship has two fundamental components. The first is the application of the skill and knowledge of the doctor in the care of the whole patient and family. The second is the right of the individual to have information about his or her illness or treatment, and to be involved in decision making. This relationship is built on trust and comes sharply into focus in the area of consent to take part in clinical trials. The argument is put forward that the use of written information should be seen as an extension of the communication between the doctor and the patient, and not as a legally restrictive device. The concept of an agreement, both on the part of the doctor and of the patient, to take part in a clinical trial is developed.

Clinical Trials as Topic↗
PubMed1983

Induction of secondary antibody responses to Plasmodium chabaudi in vitro.

Spleen cells and peripheral blood mononuclear cells (PBMC) from mice, which had recovered from infection with Plasmodium chabaudi, were induced to produce anti-P. chabaudi antibody by incubating the cells with P. chabaudi parasitized red cells in Marbrook cultures. The anti-malarial antibody was assayed using the indirect fluorescent antibody test. Spleen cells and PBMC from mice infected 2-4 months previously gave higher antibody titres in culture than similar cells from mice infected a year previously. There was a good correlation between the ability of spleen cells or PBMC to be stimulated to produce antibody in vitro and the ability of mice similar to the cell donors to resist a challenge infection. Some immunity can be adoptively transferred with both spleen cells and PBMC.

Animals↗