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Biomedical subjects

M Johnson

Publications and source records attributed to M Johnson.

At least 919 records · Page 51Linked to original sources
PubMedDate not supplied

A study of tolerance in a concordant xenograft model.

Antibody-mediated rejection appears to constitute the major difference between concordant xenografts and allografts in nonhuman primates. Consistent with its known effect on antibody responses, 5-7 addition of DSG to the conditioning regimen has extended concordant primate xenograft survival for up to 6 months after discontinuation of conventional immunosuppression. In contrast to our observations in recipients of renal allografts, donor-specific skin graft rejection can occur and even in long-term recipients may induce rejection of a previously accepted renal xenograft.

Animals↗
PubMedDate not supplied

A retrospective chart review of uncontrolled use of metformin as an add-on therapy in type 2 diabetes.

The hyperglycemia, hyperinsulinemia, insulin resistance, and obesity syndrome associated with type 2 diabetes can have debilitating consequences. The biguanide metformin has a mechanism of action that is complementary to those of insulin and the sulfonylureas, suggesting that combination therapy that includes metformin may result in improved glycemic control. The purpose of this retrospective chart review was to determine the effects of adding metformin in an uncontrolled fashion to existing therapy in obese patients with type 2 diabetes who had suboptimal glycemic control and insulin resistance. For the review, the records of 124 patients were divided into two groups: group 1 included 71 patients who were taking insulin with or without a sulfonylurea, and group 2 consisted of 53 patients who were taking a sulfonylurea alone. Metformin was added to patients' existing therapy in conjunction with downward titration of the sulfonylurea and insulin doses. A retrospective chart review was conducted at the end of 6 months for group 1 and at the end of 12 months for group 2 to determine the change from baseline in measures of diabetes control (ie, insulin and sulfonylurea dose, glycated hemoglobin [Hb A1c] value, body mass index [BMI], and lipid profiles). In group 1, the mean insulin dose decreased from 46.4 U/d at baseline to 6.1 U/d at the end of follow-up. Eighty-three percent of the patients were able to discontinue insulin therapy completely. Similarly, group 2 had statistically significant reductions in mean sulfonylurea dose. Both groups also achieved statistically significant reductions in Hb A1c, BMI, and total cholesterol level. The addition of metformin to treatment with insulin or sulfonylureas, either alone or in combination, significantly improved glycemic control and cholesterol levels and promoted weight loss in obese type 2 diabetic patients with insulin resistance. Less than 5% of patients reported mild, transient gastrointestinal side effects, none of which required cessation of metformin therapy. Five patients discontinued metformin due to lack of efficacy.

Combined Modality Therapy↗
PubMedDate not supplied

The nurse as exercise leader.

Adherence rates to our nurse-led exercise interventions were considerably higher (88%) than those reported in the literature for overweight women of this age. Bonding between the women and the nurse leaders, as well as socialization opportunities and program design, may have contributed to this high rate. Future studies would be strengthened by comparing adherence rates of women between nurse-led and non-nurse-led exercise groups. Women tested at 3 and 6 months after the intervention stated they tried many fitness clubs and spas in the area, but could find no exercise programs that were tailored to their age and fitness level or that took into consideration their individual health needs. Nurses interested and knowledgeable about changes of aging are in an ideal position to develop and lead exercise programs for older individuals, particularly those with chronic nondisabling physical problems. Nurses in this study have expanded their health-promotion role by gaining knowledge and skills in exercise science. Resources available for any nurse to gain knowledge and experience about exercise are found in the resource list.

Aged↗
PubMedDate not supplied

Pharmacologically induced myocardial ischemia: a comparison of dobutamine and dipyridamole.

The purpose of our study was to compare the ability of dobutamine and dipyridamole infusion to induce myocardial ischemia. In a population of 16 anesthetized open-chest swine, a coronary artery stenosis sufficient to abolish the hyperemic response to a 15-second total occlusion was created. Heart rate, systolic blood pressure, and dP/dt were recorded. Myocardial segment shortening was determined by sonomicrometry in all animals. In a subset of seven animals regional myocardial blood flow was measured by injection of radiolabeled microspheres. Dipyridamole was infused according to a high-dose protocol. After a washout period and reestablishment of a baseline state, dobutamine was infused incrementally. There was no significant difference between the baseline states. Dipyridamole did not affect heart rate but did significantly decrease blood pressure and rate-pressure product. Myocardial segment shortening decreased in the ischemic zone by 0.07 +/- 0.08 (p = 0.004). Dobutamine infusion significantly increased heart rate, blood pressure, and rate-pressure product. Myocardial segment shortening in the ischemic zone decreased by 0.17 +/- 0.09 (p < 0.001). Dobutamine decreased blood flow in the ischemic zone relative to baseline. Both dobutamine and dipyridamole infusion resulted in myocardial ischemia. The magnitude of the ischemic response is greater for dobutamine than for dipyridamole.

Animals↗
PubMedDate not supplied

Use of the Centritech Lab centrifuge for perfusion culture of hybridoma cells in protein-free medium.

As part of an effort to develop a suspension-culture perfusion-based process with high flow rate without the fouling and antibody retention inherent to filter-based cell-separation devices, we have evaluated and contributed to the development of the Centritech Lab centrifuge for the perfusion culture of hybridoma cells in protein-free medium. Culture start-ups showed that cell growth and monoclonal-antibody (MAb) production rates were similar in both a spinner flask and continuous centrifugation coupled to a bioreactor. The centrifuge efficiently separated viable cells from dead ones. Viable-cell recoveries were never below 98%, whereas dead-cell recoveries were usually around 80%. The cell content of the centrifuge supernatant and concentrate was strongly determined by the total amount of cells, viable and dead, in the culture broth, but an influence of the centrifugation parameters (feed rate, times of separation and discharge, and rotor speed) was observed. This understanding of the separation process inside the centrifuge is important and may apply to other similar devices. Monoclonal antibodies were not retained in the bioreactor during centrifugation perfusion. However, whereas similar growth rates were obtained in perfusion cultures using either continuous centrifugation or filtration, MAb concentrations were 35% lower in the former case. Utilization of the centrifuge in an intermittent fashion decreased the daily cell residence time outside the bioreactor, the daily pelleted-cell residence time in the centrifuge, and the frequency of cell passage to the centrifuge. This led to higher viable-cell numbers in the bioreactor and an accompanying increase in MAb concentrations, 225-250 mg of IgM L-1, equal to the performance of filter-based perfusion systems with the same cell line. It was hypothesized that having cells periodically packed at the bottom of the centrifuge insert (up to 800 x 10(6) cells mL-1) is deleterious to the culture by exposing the pelleted cells to prolonged nutrient limitations.

Animals↗
PubMedDate not supplied

Algorithm for naming molecular equivalence classes represented by labeled pseudographs.

The emergence of large chemical databases imposes a need for organizing the compounds in these databases. Mapping the chemical graph in particular, and a molecular equivalence class represented by a labeled pseudograph in general, to a unique number or string facilitates high-throughput browsing, grouping, and searching of the chemical database. Computing this number using a naming adaptation of the Morgan algorithm, we observed a large classification noise in which nonisomorphic graphs were mapped to the same number. Our extensions to that algorithm greatly reduced the classification noise.

Journal Article↗
PubMedDate not supplied

Implementing cancer pain education for medical students.

PURPOSE: The purpose of this study was to develop and pilot a cancer pain education course for medical students, using a structured home hospice visit. DESCRIPTION OF STUDY: A 1-hour home hospice visit was presented to 57 senior medical students. The content and objective criteria for the structured home hospice visit were developed by a multidisciplinary group of experts. During a 1-hour interview, students completed a cancer pain history, performed a focused physical examination, and received feedback and teaching regarding the essentials of cancer pain management from the hospice nurse. All students and hospice patients completed a multi-item evaluation questionnaire with a 5-point Likert scale (1=strongly disagree; 5=strongly agree) regarding the structured home hospice visit. RESULTS: Most students agreed strongly that the home hospice visit was a positive experience (mean +/- SD 4.8 +/- 0.44) that helped them to understand the management of cancer pain (mean 4.7 +/- 0.46) and opioid-related side effects (mean 4.5 +/- 0.57). Most patients enjoyed visiting with the students (mean 4.90 +/- 0.30), agreed that the visit was not tiring (mean 4.81 +/- 0.51), and felt that they benefited from participating (mean 4.76 +/- 0.54). CLINICAL IMPLICATIONS: The authors concluded the following: 1) that medical students benefited from learning about cancer pain assessment and management through the use of a structured home hospice visit; 2) that a structured home hospice visit helped the students to learn the basics of cancer pain management; 3) that patients enjoyed their role as teacher for medical students; and 4) that senior hospice nurses provided excellent instruction for medical students in the management of cancer pain.

Curriculum↗
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Coping styles of pregnant adolescents.

This descriptive study examined the coping styles and specific strategies used by a group of pregnant adolescents attending an adolescent family support service. Seventy-one adolescents, with a mean age of 17 years, and a mean gestation of 25 weeks, completed the Revised Jalowiec Coping Scale (JCS-R). The findings demonstrated that the optimistic coping style (emotion-focused) was the most frequently used and most effective coping style for these young women. A confrontive coping style (problem-focused) was also used and found to be effective. A combination of problem-focused and emotion-focused styles is recommended, with an increased emphasis on problem-focused approaches. The focus by the adolescents on optimistic approaches is suggestive of a lack of understanding of the challenges that motherhood will place upon them, but is consistent with their age and developmental stage. A longitudinal study of coping styles and changes in style throughout pregnancy and early motherhood is recommended. Initial assessment and monitoring of coping styles of pregnant adolescents is proposed. This assessment would be the beginning point for a teaching program that highlights increased use of adaptive coping styles (problem-focused) with decreased use of maladaptive approaches, and includes emotion-focused styles. By expanding the repertoire of coping styles and strategies available to the adolescent, the public health nurse (PHN) prepares these vulnerable mothers for the challenges ahead.

Adaptation, Psychological↗
PubMedDate not supplied

Home-screen: a short scale to measure fall risk in the home.

Community nurses are often the health professionals with whom older Australians living at home have most contact. The home environment has been identified to have a number of hazards associated with falls in older people. The Home-screen scale was specifically designed as a nurse-administered instrument to identify environmental and behavioral risks that alert nurses to the need for action to reduce fall risks in the home. A 14-item scale was administered to 1,165 older people receiving community nursing services. Psychometric investigation confirmed a 10-item scale with construct validity and internal consistency (alpha = 0.86, n = 989), explaining 60% of the construct of home safety (safe home environment and safe home behaviors). In addition, differences in mean scores were found in clients able and unable to transfer independently (t = 4.5 [df = 323.1] p < 0.001 [Group 1: M = 82.14, SD = 15.56; Group 2: M = 75.54, SD = 20.83, n = 989]). Similarly, an association existed between clients with low scores on the Home-screen scale and the perceived need for home modification. A score of 74 on this scale has been identified as a critical point for potential client injury. The use of this scale, both as an initial screening instrument and as a monitoring tool for community nurses working with older people, is recommended.

Accidents, Home↗
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The role of emergency medical services in primary injury prevention. East Carolina Injury Prevention Program.

Injury is a leading cause of death and disability. Preventing injuries from ever occurring is primary injury prevention (PIP). The objective of this statement is to present the consensus of a 16-member panel of leaders from the out-of-hospital emergency medical services (EMS) community on essential and desirable EMS PIP activities. Essential PIP activities for leaders and decision makers of every EMS system include: protecting individual EMS providers from injury; providing education to EMS providers in PIP fundamentals; supporting and promoting the collection and utilization of injury data; obtaining support for PIP activities; networking with other injury prevention organizations; empowering individual EMS providers to conduct PIP activities; interacting with the media to promote injury prevention; and participating in community injury prevention interventions. Essential PIP knowledge areas for EMS providers include: PIP principles; personal injury prevention and role modeling; safe emergency vehicle operation; injury risk identification; documentation of injury data; and one-on-one safety education.

Community-Institutional Relations↗
PubMedDate not supplied

Spectral analysis of Lapine EEG: neurotoxicologic evaluation of new nonionic contrast media.

Effects of the injection of 0.25 ml of nonionic radiocontrast media (280 mg I/ml) and/or istonic and/or hypertonic mannitol into the subarachnoid space on the low frequencies (2--5 Hz) of the EEG were studied in nonanesthetized, curarized rabbits. Compared to the noninjected controls, mannitol did not cause any significant EEG spectrum shifts. P-297 and iopamidol caused a slight decrease in the energy content of the 2--5-Hz band, while DS-1-132 and the nonionic dimer ZK 32347 caused a moderate increase. Since an increase in the slow-wave component of the EEG indicates a pacemaking activity, while a decrease indicates stimulation or irritation, none of the tested nonionic media appear to be biological inert. In this test P-297, iopamidol, and DS-1-132 caused fewer disturbances than metrizamide.

Animals↗
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Posterior spinal fusion in paralytic scoliosis and myelomeningocele.

The Shriners Hospital, Lexington, KY, experience with posterior spinal fusion for scoliosis in 50 patients with myelomeningocele was reviewed. Six patients were fused with Harrington rods and 47 of 50 patients were treated with some form of segmental fixation. The complication rate was 48% (24/50) resulting in 1.48 procedures per patient. The deep infection rate was 8% (4/50) and the pseudarthrosis rate was 16% (8/50). The use of modern segmental instrumentation systems has improved the pseudarthrosis rates for posterior spinal fusion in scoliosis associated with myelomeningocele but not to the point of displacing the current approach of an anterior and posterior spinal fusion.

Adolescent↗
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Effect of probucol therapy on plasma fatty acid composition during postprandial lipemia in hypertriglyceridemia.

OBJECTIVE: To determine the effect of probucol (PR) on fatty acid composition of plasma lipids in patients with hypertriglyceridemia during the fasting and postprandial states. DESIGN: Open-label, single-center, 6-week treatment, baseline-controlled trial. SETTING: Outpatient clinical research center. PATIENTS: Six patients with established hypertriglyceridemia and no complicating medical conditions. INTERVENTION: Step 1 American Heart Association diet and no lipid-lowering medications for at least 4 weeks. Lead to a baseline standarized meal ingestion with postprandial blood samplings. After 6 weeks of treatment with 500-mg of PR twice daily and diet, the meal tests were repeated. MEASUREMENTS: The clinical status, 3-day food records, postprandial blood samplings (0, 2, 4, 6, and 8 hours) for lipid and fatty acids in whole plasma, triglyceride (TG), phospholipid (PL), and cholesteryl ester (CE) fractions. RESULTS: PR had the following effects: (1) In plasma, cholesterol, high-density lipoprotein cholesterol, apolipoprotein (Apo) A1, and ApoB were decreased postprandially. ApoC111 ratio (heparin-treated plasma versus precipitate) was decreased in the fasting state. (2) The saturated/unsaturated (S/U) fatty acid ratios in the PL, TG, and CE fractions were elevated postprandially and increased in CE in the fasting state. In the PL fraction it was due to an increase in the percentage of myristic, palmitic, stearic, and oleic acids and a decrease in linolenic, eicosatrienoic, and arachidonic acids. In the TG and CE fractions the changes were not due to any particular patterns of fatty acids. The ratio of arachidonic/eicosatrienoic acid was decreased postprandially in PL and CE fractions. The ratio of eicosatrienoic/linoleic acid was decreased in PL and increased in CE fractions. (3) The S/U ratio in the lipoprotein (Lp) B and LP(a) lipid components decreased in PL and CE. Lp(a) was more saturated with respect to fatty acids than LpB. CONCLUSION: PR treatment for 6 weeks increased postprandial S/U fatty acid ratios. This was due to a combination of an increase in saturated and monounsaturated levels and a decrease in polyunsaturated levels. The effect was most notable in the PL fraction. In those systems dependent on the pattern of fatty acids, the fatty acid compositional change could modify biological responses in clinically important ways during lipid-lowering therapy. The change toward saturation of fatty acids in the postprandial state may contribute to the antioxidant properties of probucol.

Anticholesteremic Agents↗
PubMedDate not supplied

Determining flexor-tendon repair techniques via soft computing.

An SC-based multi-objective decision-making method for determining the optimal flexor-tendon repair technique from experimental and clinical survey data, and with variable circumstances, was presented. Results were compared with those from the Taguchi method. Using the Taguchi method results in the need to perform ad-hoc decisions when the outcomes for individual objectives are contradictory to a particular preference or circumstance, whereas the SC-based multi-objective technique provides a rigorous straightforward computational process in which changing preferences and importance of differing objectives are easily accommodated. Also, adding more objectives is straightforward and easily accomplished. The use of fuzzy-set representations of information categories provides insight into their performance throughout the range of their universe of discourse. The ability of the technique to provide a "best" medical decision given a particular physician, hospital, patient, situation, and other criteria was also demonstrated.

Cadaver↗