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J McKnight

Publications and source records attributed to J McKnight.

17 recordsLinked to original sources
PubMed1992

Domains of the catalytically self-sufficient cytochrome P-450 BM-3. Genetic construction, overexpression, purification and spectroscopic characterization.

1. The gene CYP102 encoding cytochrome P-450 BM-3 and subgenes encoding the cytochrome P-450 and cytochrome P-450 reductase domains have been cloned in Escherichia coli. 2. The protein products of these genes have been overexpressed and purified to homogeneity. 3. The cytochrome P-450 domain is purified in the ferric low-spin state, but is readily converted into the high-spin state by addition of the substrate palmitate (Ks = 1 microM). The cytochrome P-450 reductase domain readily reduces cytochrome c. Mixing the two domains reconstitutes only about one-thousandth of the fatty acid hydroxylase activity associated with the intact cytochrome P-450 BM-3. 4. The X-band e.p.r. spectra of both the cytochrome P-450 domain and intact cytochrome P-450 BM-3 give g-values indicating low-spin ferric haem. The spectra are virtually identical with those of the equivalent form of cytochrome P-450 cam indicating that the haem ligation in cytochrome P-450 BM-3 is identical with that of cytochrome P-450 cam. 5. Resonance Raman spectra of the substrate-free and substrate-bound forms of the cytochrome P-450 domain are given. Spectral differences in comparison with cytochrome P-450 cam may reflect subtle electronic differences between the respective haem environments.

Bacillus megaterium↗
PubMed1992

Curriculum innovation for gerontological nursing in Canada: a health for all systems based approach.

This paper presents an educational model that follows the General Systems approach and illustrates the advancement of gerontological nursing education in Canada. The model's primary focus is placed on baccalaureate education, the mandate of the nursing discipline group. The paper also touches briefly on Masters and Doctoral education. Implications for use of this model in nursing education are then linked to nursing care of the elderly.

Curriculum↗
PubMed1991

Amphotericin B vs high-dose ketoconazole for empirical antifungal therapy among febrile, granulocytopenic cancer patients. A prospective, randomized study.

We compared high-dose ketoconazole (800 mg/kg per day, orally) with amphotericin B (0.5 mg/kg per day, intravenously) for empirical antifungal therapy in a prospective, randomized study of persistently or recurrently febrile granulocytopenic cancer patients. Among 97 patients eligible for empirical antifungal therapy, 20 (21%) of these patients were ineligible for randomization to ketoconazole treatment because of their inability to tolerate oral medications. Among 72 patients eligible for randomization, 64 were assessable (32 in each arm of the study). Five of six patients with proved fungal infections who were randomized to receive ketoconazole treatment required crossover to amphotericin B treatment because of progressive infection. The conditions of three of these five patients improved after receiving amphotericin B. The frequency of transaminase elevation was higher in those receiving ketoconazole, while the frequency of azotemia was higher in those receiving amphotericin B. Bioavailability of ketoconazole was unpredictable. Amphotericin B remains the drug of choice for empirical antifungal therapy in granulocytopenic patients; whereas, lack of a parenteral formulation, ineffectiveness against proved mycoses, and unreliable bioavailability preclude high-dose ketoconazole from being an appropriate compound for this purpose.

Adult↗
PubMed1990

Interleukin 2 and lymphokine-activated killer cell therapy: analysis of a bolus interleukin 2 and a continuous infusion interleukin 2 regimen.

Several groups have described the efficacy of interleukin 2 (IL-2) plus lymphokine-activated killer (LAK) cells in the treatment of cancer patients with significant response rates noted in patients with renal cell cancer and malignant melanoma; however, the optimum regimen remains undefined. The Biological Response Modifiers Program of the National Cancer Institute conducted two consecutive Phase I/II studies evaluating the toxicity and clinical efficacy of different methods of IL-2 and LAK cell therapy. In the first trial, we modified the standard Rosenberg regimen by decreasing the duration of priming in an attempt to reduce the toxicity related to this phase of the therapy and thereby administer more IL-2 doses with the LAK cells. In the second trial, we used a continuous i.v. infusion IL-2 regimen and altered both the leukapheresis procedure and the LAK cell culture techniques based on our in vitro and preclinical studies suggesting that 2-day LAK cells were superior. Thirty cancer patients received i.v. bolus IL-2 at 100,000 units/kg every 8 h for 3 days during priming and for 5 days during LAK cell administration. A second group of 22 cancer patients received IL-2 by continuous i.v. infusion at 3 x 10(6) units/m2 for 5 days during priming and an additional 5 days of IL-2 with the LAK cell phase of the treatment. The timing of the start of the leukapheresis procedures, their duration and number, and the LAK cell culture techniques differed in the two trials. Overall, 52 patients with various cancers were treated. The toxicities associated with each regimen were similar to those seen in other IL-2 plus LAK cell trials. Four patients (one each with melanoma and diffuse large cell lymphoma and two with renal cell cancer) exhibited partial responses lasting 2, 4, 10, and 15+ mo. Serial tumor biopsies from treated patients demonstrated that therapy can produce a marked mononuclear cell infiltrate and an increase in HLA-DR expression on tumor cells. There was no difference in the overall response rate between the two regimens, but toxicity was less with continuous i.v. infusion IL-2. The 5-day continuous i.v. infusion regimen resulted in significantly higher rebound lymphocytosis, cell yield from leukapheresis, and number of LAK cells harvested from culture.

Adolescent↗
PubMed1989

Learning clinical teaching skills at the baccalaureate level.

Nurses returning to work after obtaining their baccalaureate degree in nursing find increased expectations to participate in student and staff clinical education. Often these nurses are not prepared for this role. This paper describes a project that involved final year post-diploma registered nurse students in the clinical teaching of second year basic degree students in a baccalaureate nursing programme. Results of a pilot study to determine if the perceptions of the students involved in the teaching project changed following the experience, show a more positive change in teacher behaviours in these student tutors compared to students doing a traditional clinical experience. Course evaluations indicate the experience increased knowledge and comfort in clinical teaching and point to positive changes in the perceptions of behaviours conducive to clinical teaching.

Clinical Competence↗
PubMed1989

Experiences of nursing joint appointments in a teaching health unit.

This article describes the experiences of five community health nursing faculty who are jointly appointed between McMaster University School of Nursing and the Hamilton-Wentworth Department of Public Health Services in Hamilton, Ontario, Canada. The appointees are actively involved in service, education, and research activities within the teaching health unit, a specially funded project of the Ontario Ministry of Health. Various kinds of consultation and expertise are offered by joint appointees to staff and management within the Department of Public Health Services. The amount of time and effort invested in a particular activity or project varies as staff, students, and joint appointees each make their contributions. Several lessons are learned in acting out our diverse roles in this exciting and challenging service environment.

Community Health Nursing↗
PubMed1986

A randomized trial comparing ceftazidime alone with combination antibiotic therapy in cancer patients with fever and neutropenia.

To assess the efficacy of single-agent therapy relative to standard combination antibiotic therapy for the initial management of fever and neutropenia in cancer patients, we conducted a randomized trial comparing ceftazidime alone with a combination of cephalothin, gentamicin, and carbenicillin. Of 550 evaluable episodes of fever and neutropenia, 282 were treated with ceftazidime alone and 268 with the combination. All episodes were evaluated for responses at 72 hours after the start of treatment and at resolution of the neutropenia. Of the patients with unexplained fever who were given ceftazidime alone, 99 percent were alive at 72 hours and 98 percent were alive when the neutropenia resolved, as compared with 100 percent and 98 percent, respectively, of those given combination therapy. Of the patients with documented infection who were given ceftazidime alone, 98 percent were alive at 72 hours and 89 percent when the neutropenia resolved, as compared with 98 percent and 91 percent, respectively, of those given combination therapy. The majority of episodes of documented infection in both treatment groups necessitated additional antimicrobial treatment or other modifications of the initial regimen, as compared with only 22 percent of the episodes of unexplained fever. We conclude that initial single-agent therapy with certain beta-lactam antibiotics is a safe alternative to standard combination antibiotic therapy, although patients with documented infection or protracted neutropenia are likely to require additional or modified treatment.

Adolescent↗
PubMed1985

New beta-lactam antibiotics in granulocytopenic patients. New options and new questions.

Infectious complications are a frequent cause of morbidity and, at many centers, the major cause of death in patients with cancer. The increased risk and severity of infectious sequelae result from profound alterations in normal host defenses that occur secondary to the underlying malignancy and the treatment thereof. During the last decade, early empiric antibiotic therapy has become standard practice in the initial management of febrile granulocytopenic patients and has contributed significantly to the improved outcome among patients undergoing cancer therapy. Although early death due to unsuspected or inadequately treated bacterial infection has been largely overcome, new problems--also with life-threatening implications--have emerged. As the use of cancer chemotherapy continues to increase, new populations of patients are being placed at increased risk of infection. Defining the host and environmental factors that contribute to this risk assumes central importance for delineating those patients who require the most intense surveillance. Changing medical practices (e.g., increased use of indwelling catheters) have contributed to the emergence of new pathogens. Recent drug developments (e.g., the third-generation cephalosporins and extended-spectrum penicillins) offer new treatment options, as well as generate controversy and confusion. For example, authorities disagree on the optimal duration and modifications in treatment that are required by cancer patients who remain granulocytopenic and who thus are at continued risk of multiple infectious episodes or superinfections. A question of current interest is whether combination therapy with synergistic agents is important in light of the development of the third-generation cephalosporins and extended-spectrum penicillins. Several of these new antibiotics have an exceedingly broad spectrum of activity that includes Pseudomonas aeruginosa, as well as Enterobacteriaceae, Serratia, Citrobacter, indole-positive Proteus, and anaerobes (including Bacteroides fragilis). However, the third-generation cephalosporins are not as active against staphylococci and streptococci as are the first-generation cephalosporins, and none is effective against enterococci. Nonetheless, these agents achieve serum levels that can be 10 to 100 times greater than the minimal inhibitory and bactericidal concentrations of gram-negative bacteria, raising the possibility that these drugs might be effective as single agents. The advantages of the third-generation cephalosporins are their minimal toxicity and long serum half-lives.(ABSTRACT TRUNCATED AT 400 WORDS)

Agranulocytosis↗
PubMed1979

High dose flupenthixol decanoate in chronic schizophrenia.

In a double-blind trial, female 'drug-resistant' chronic schizophrenic in-patients were given high dose or standard dose flupenthixol decanoate for 13 weeks. Plasma flupenthixol levels showed a five-fold interindividual variation, but were consistently higher with the high dose. Analysis of final scores showed no statistically significant differences between groups with regards to mental state, ward behaviour and extrapyramidal side-effects. When compared with pre-trial scores, the extrapyramidal side-effects worsened significantly in the high dose patients and social withdrawal decreased in the standard dose patients. The mental state of a sub-group of patients, possibly drug resistant for pharmacokinetic reasons, improved significantly on the high dose over the 13 weeks.

Adult↗
PubMed1977

Theme and variation in the development of the first transitional object.

In our research we have been attempting to elucidate the phenomenon we have labelled the 'first transitional object'. In this paper we have focused primarily on some dimensions along which the child can vary in his use of the first transitional object. We have pointed to the fact that some infants first come in contact with the 'blanket' at the age of three months, and this seems to be a critical time period for regular contact with the first transitional object. While there are variations in the child's attachment to the first transitional object from the very beginning, age two appears to be a crucial time when the intensity of the child's attachment to the 'blanket' becomes established. Most children seem to give up the first transitional object between five and six years of age, and an example of the disruption of this process was presented. An attempt was made to put these findings within a developmental context, while other variables which affect the fate of the first transitional object were also explored.

Age Factors↗