Blood collection and analytical considerations in blood lead screening in children.
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Blood Specimen Collection↗
Biomedical subjects
J Hogan
Publications and source records attributed to J Hogan.
Patient postcoding and the GDS.
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Capitation Fee↗
Latency of skeletal muscle contraction after pulse train stimulation: an important factor in correct timing of skeletal muscle cardiac assist devices.
Various configurations of conditioned skeletal muscle are under investigation for cardiac assistance in patients with end-stage cardiac failure. Optimal timing of conditioned skeletal muscle contraction is essential for effective cardiac augmentation. However, unlike mechanical methods of assistance, skeletal muscle requires time to develop peak tension. We measured "time to 50% peak tension" and "time to 90% peak tension" using an electrical strain gauge in 12 canine latissimus dorsi muscles (6 untrained controls and 6 trained with 3 months of electrical stimulation at 25 Hz with a 15% duty cycle). The "time to 50% relaxation" and the "time to 90% relaxation" after discontinuation of the stimulus were also measured. Conditioned skeletal muscle required significantly more time to develop peak tension than unconditioned skeletal muscle. Relaxation was also significantly prolonged in conditioned muscle. Notably, conditioned lattisimus needed, on average, 0.35 sec to develop peak tension and 0.20 sec for 90% relaxation. Thus, 0.55 sec of each muscle contraction/relaxation cycle was devoted to development of peak tension and subsequent relaxation. At normal canine heart rates of approximately 120 beats per minute (0.50 sec per cardiac cycle), conditioned skeletal muscle may take up to 70% of each cardiac cycle (0.35 sec) to develop 90% of peak tension. The recognition of this phenomenon in conditioned skeletal muscle is important for effective contraction timing of both human and animal skeletal muscle assist devices. Development of proper conditioning regimens for such devices may benefit from identification of those training parameters which produce a minimal "time to peak tension."
Animals↗
Oxygen delivery augmentation by low-dose perfluorochemical emulsion during profound normovolemic hemodilution.
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Animals↗
What we know about leadership. Effectiveness and personality.
Although psychologists know a great deal about leadership, persons who make decisions about real leaders seem largely to ignore their accumulated wisdom. In an effort to make past research more accessible, interpretable, and relevant to decision makers, this article defines leadership and then answers nine questions that routinely come up when practical decisions are made about leadership (e.g., whom to appoint, how to evaluate them, when to terminate them.
Humans↗
Enhanced oxygen delivery by perflubron emulsion during acute hemodilution.
A high-concentration 90% w/v perflubron (perfluorooctyl bromide [PFOB]) emulsion (Oxygent HT) is being evaluated as an oxygen carrier for use during surgery. This study was done to assess oxygen delivery by Oxygent HT during acute normovolemic hemodilution. Anesthetized mongrel dogs, instrumented with femoral and pulmonary artery catheters, were hemodiluted to a hematocrit of 25% with 3:1 (v/v) of Ringers-lactate (R-L). Dogs were then ventilated with 100% O2 and hemodiluted to a Hct approximately 11% with 1.5 (v/v) of colloid (autologous plasma and 5% albumin). Dogs then received either 3.3 mL/kg Oxygent HT (n = 5) or 3.3 mL/kg R-L (n = 4), and were monitored for 3 hours. Total oxygen delivery (DO2), blood oxygen content, cardiac output, mixed venous PO2, and mixed venous Hb saturation was higher in Oxygent HT treated dogs compared to the R-L controls. The percentage of total DO2 contributed by perflubron-dissolved oxygen was about 8-10% and accounted for 25-30% of total oxygen consumption (VO2). The percentage of VO2 contributed by Hb-carried oxygen was significantly higher in R-L controls (46 +/- 4%) than in the treated dogs (15 +/- 3%), indicating that the availability of the perflubron-dissolved oxygen allowed for a reserve of oxygen to remain available in the red blood cells.
Animals↗
Characterization and mechanism of side-effects of Oxygent HT (highly concentrated fluorocarbon emulsion) in swine.
Perfluorooctyl bromide is an oxygen-carrying perfluorocarbon presently under development as an artificial blood substitute (Oxygent HT). Intravenous (i.v.) Oxygent HT elicits a mild side-effect profile in man characterized by early onset headache and nausea and delayed onset fever. Early onset flushing has also been observed. Species of Artiodactyla are sensitive to particulate injections and demonstrate a transient pulmonary hypertensive response thought to be associated with the large number of pulmonary intravascular macrophages found in these species. Because of this sensitivity, we chose the swine as a model for further investigations. In anesthetized and conscious swine, i.v. Oxygent HT transiently increased mean pulmonary artery pressure (mPAP) and caused flushing. Both effects peaked at 30 min post injection and were resolved by 2 hrs. Plasma thromboxane B2 (TxB) increased in response to Oxygent HT. Oxygent HT-induced changes in mPAP, flush, and plasma TxB were blocked by aspirin and ibuprofen. Dexamethasone and SQ 29,548 (thromboxane receptor antagonist) blocked the mPAP increase. In conscious swine, Oxygent HT caused a febrile response which was blocked by ibuprofen or dexamethasone. Thus, both early- and late-onset effects of Oxygent HT in swine are blocked by interference with the arachidonic acid cascade. These findings suggest that the 2-phase "flu-like" syndrome induced by Oxygent HT is secondary to the release of products of the arachidonic acid cascade and may be effectively prophylaxed in man with corticosteroids or long plasma half-life cyclooxygenase inhibitors.
Animals↗
Intervening with high risk youth: a program model.
This paper describes a program model being implemented for older, high-risk adolescents who are beginning to exhibit significant substance use problems. The program provides an initial assessment and refers clients to appropriate services. Only a small percentage are being referred to inpatient treatment; most clients enter outpatient intervention groups, which are conducted by the program. These groups have three purposes: to allow staff to monitor and evaluate clients so that those who are in imminent danger can be placed in protective treatment settings; to help clients see themselves as candidates for recovery and to introduce them to treatment resources by accompanying them to AA and NA meetings; and to change behavior, a goal that seems more immediately achievable for youth with stable community ties who have more to lose if they get into further trouble. Besides describing the program model, this paper examines some of the difficulties of getting referrals from a variety of community agencies.
Adolescent↗
Pathologists' participation in postmortem examinations for patients with dementia.
Pathologists (n = 571) in Michigan were surveyed to examine the problem of limited access to autopsy experienced by families of patients with dementia and to assist with the implementation of the Michigan Dementia Program. The survey determined the extent to which pathologists performed autopsies for patients with dementia and/or were willing to do so as part of a statewide Postmortem Examination Program. Responses from 394 pathologists (69%) indicated that 49% were willing to perform brain removal and 44% were interested in learning more about the statewide program. The survey results were used to recruit pathologists, to identify potential problems, and to provide baseline data against which to measure the effects of a fully implemented program.
Attitude of Health Personnel↗
Epstein-Barr virus in normal, pre-malignant, and malignant lesions of the uterine cervix.
AIM--To detect the presence or absence of Epstein-Barr virus (EBV) in cervical lesions ranging from normality to invasive malignancy. METHODS--Eighteen randomly selected cases of invasive squamous cell carcinomas of the uterine cervix were examined as well as 25 cases each of normal cervices and those showing cervical intra-epithelial neoplasia (CIN) I, II, and III. DNA-DNA in situ hybridisation, using a biotinylated probe to the Bam H1 "W" fragment of EBV, was carried out in addition to the polymerase chain reaction using specific primer sequences that flank a 153 base pair segment of the Bam H1 "W" region of the EBV genome and which do not cross-amplify other DNA herpes viruses. Positive control material included paraffin wax embedded P3 HR1 lymphoblastoid cells (containing high copy numbers of EBV) and two nasopharyngeal carcinomas positive for EBV. RESULTS--Neither normal nor CIN I tissue was positive. Eight per cent of CIN II tissue was positive; 8% of CIN III, and 43% of carcinomas were positive for EBV. CONCLUSION--The study shows that the virus is present in some cases of cervical carcinoma and to a lesser degree in some premalignant lesions of the cervix, but the exact association between it and cervical oncogenesis, be it causative or incidental, remains to be determined.
Base Sequence↗
Direct myocardial transfection in two animal models. Evaluation of parameters affecting gene expression and percutaneous gene delivery.
BACKGROUND: Gene therapy represents a novel approach to the treatment of a variety of disease states. Direct injection of pure untreated DNA into skeletal and cardiac muscle is sufficient to perform gene transfer in vivo. Little information is available, however, regarding the extent to which individual parameters of direct gene delivery affect the efficiency of myocardial transfection. Moreover, the fact that all previously reported studies of successful myocardial transfection were performed using open chest surgery to visualize the heart for direct injection of DNA constitutes a potential limitation to clinical applications of myocardial gene transfer. The objectives of the present study were: (a) to determine the extent to which gene expression is altered by varying the amount of DNA and the volume of the delivery vehicle; (b) to study whether protracted expression of DNA persists after direct myocardial transfection; and (c) to test the feasibility of percutaneous, transthoracic myocardial injection of DNA. EXPERIMENTAL DESIGN: New Zealand white rabbits (N = 30) were transfected with the firefly (Photinus pyralis) luciferase reporter gene. Twenty-three rabbits were segregated into 5 groups according to the amount of DNA and volume of delivery vehicle injected. These rabbits were sacrificed at 5 days posttransfection to measure the level of luciferase gene expression. Three more rabbits were designated exclusively for in situ hybridization. Two rabbits were sacrificed at 5 and 6 months, respectively to evaluate long-term expression. Two additional rabbits were used as controls. Yucatan microswine (N = 4) were used to evaluate the feasibility of percutaneous, transthoracic myocardial transfection with beta-galactosidase or luciferase reporter genes. Microswine were sacrificed immediately post-sham transfection (N = 2), or 5 days postmyocardial transfection (N = 2). RESULTS: Among 11 rabbits, transfection with 10 micrograms of DNA (N = 4), 25 micrograms of DNA (N = 3), and 50 micrograms of DNA (N = 4) in 100 microL of injectate yielded a step-wise but statistically insignificant increase in luciferase activity. Among 16 rabbits, transfection with 50 micrograms of DNA in injectate volumes of 50 microliters (N = 4), 100 microliters (N = 4), 150 microliters (N = 4), and 300 microliters (N = 4) yielded a statistically significant (p < 0.05) increase in luciferase activity in those hearts transfected with 300 microliters compared with those hearts transfected with either 50 or 100 microliters. Luciferase activity at 5 and 6 months postmyocardial transfection was 7.14 and 68.8 Turner light units, respectively. In situ hybridization confirmed that myocytes represented the site of luciferase expression. Percutaneous myocardial transfection was successfully accomplished with both reporter genes. CONCLUSIONS: The results of the present study demonstrate that increasing the amount of DNA employed for direct myocardial transfection fails to produce a statistically significant increase in the level of gene expression. In contrast, increasing the volume of injectate used to directly transfect a constant amount of DNA (50 micrograms) produced significantly augmented expression of the reporter luciferase gene. Luciferase expression was detected 6 months posttransfection. Successful transfection after fluoroscopic-guided direct percutaneous delivery suggests that it may be feasible to deliver genetic material into the myocardium of patients in a similar fashion.
Animals↗
Endometrial and pulmonary sarcoidosis.
A 33 year old woman with irregular menses due to endometrial sarcoidosis and a family history of sarcoidosis is described. Its relative increase in importance in the wake of the decline in the incidence of genital tract tuberculosis in Ireland is discussed.
Adult↗
LIPIDAT: a database of lipid phase transition temperatures and enthalpy changes. DMPC data subset analysis.
The systematic study of the mesomorphic phase properties of synthetic and biologically derived lipids began some 30 years ago. In the past decade, interest in this area has grown enormously. As a result, there exists a wealth of information on lipid phase behavior, but unfortunately these data have until now been scattered throughout the literature in a variety of books, proceedings and journals. The data have recently been compiled in a centralized database, LIPIDAT, with a view to providing ready access to the data and to the appropriate literature. LIPIDAT consists of a tabulation of all known mesomorphic and polymorphic phase transition temperatures and enthalpy changes for synthetic and biologically-derived lipids in the dry and in the partially and fully hydrated states. Also included is the effect of pH, and of salt and metal ion concentration and other additives such as proteins, drugs, etc., on the thermodynamic values. The methods used in making the measurements and the experimental conditions are reported. Bibliographic information includes comprehensive literature referencing and list of authors, but does not at the present time include article titles. As of this writing, the database is current through June, 1990 and is approaching 10,000 records in length. Each record contains 28 fields. In this paper we report the contents and present an analysis of LIPIDAT as it refers to fully hydrated 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). This database subset represents about 7% of all LIPIDAT records. It includes data collected over a 23-year period from 1967 to 1989 and consists of 702 records obtained from 336 articles in 55 different journals. The number of records per year rises steadily beginning in 1971, reaches a maximum of 89 records/year in 1977 and remains relatively constant at 60-70 records/year in the succeeding period. Journals making the greatest contribution to the DMPC subset include Biochimica et Biophysica Acta, Biochemistry, Chemistry and Physics of Lipids and the Biophysical Journal. These four journals account for 71% of the total records in the database subset. The analysis shows that differential scanning calorimetry, electron spin resonance, fluorescence, nuclear magnetic resonance and Raman spectroscopy are the methods most commonly used for DMPC transition temperature determination. An interesting pattern emerges as to the place in time the different methods assume or loose popularity.(ABSTRACT TRUNCATED AT 400 WORDS)
Calorimetry, Differential Scanning↗
Evaluation of a chemiluminescent DNA probe assay for the rapid confirmation of Listeria monocytogenes.
A Listeria monocytogenes-specific, acridinium-ester-labelled DNA probe was evaluated in a chemiluminescent homogeneous protection assay (HPA) for the rapid confirmation of suspect L. monocytogenes colonies from blood agar plates. The HPA uses an acridinium-ester-labelled chemiluminescent DNA probe in a free-solution hybridization format. After the DNA probe hybridized with the target ribosomal RNA, the acridinium label on the unhybridized probe was inactivated by a chemical differential hydrolysis step. Formation of a hybrid between probe and target was detected in a luminometer after the addition of a detection reagent. The assay can be completed in 30 to 45 min and allows for simultaneous processing of several (50-100) samples. The probe showed 100% sensitivity and 100% specificity for L. monocytogenes when evaluated in the HPA against L. monocytogenes, other Listeria species and other Gram-positive bacteria. The lower detection limit of the HPA was between 10(4) and 10(5) cells. In an evaluation with 296 bacterial colonies isolated from food, the HPA colony confirmation showed 100% agreement with conventional biochemical characterization. HPA will be useful for the rapid confirmation of L. monocytogenes isolated from food and clinical specimens.
Acridines↗
Refractory hypoxaemia after pneumonectomy: diagnosis by transoesophageal echocardiography.
A patient with normal oxygenation before operation became very breathless and hypoxaemic after a right pneumonectomy. Transoesophageal echocardiography showed right to left interatrial shunting due to a patent foramen ovale. Transoesophageal echocardiography should be included in the assessment of patients who became inappropriately dyspnoeic after pneumonectomy.
Cardiac Catheterization↗
Diacetylenic lipid microstructures: structural characterization by X-ray diffraction and comparison with the saturated phosphatidylcholine analogue.
Thermotropic and lyotropic mesomorphism in the polymerizable lecithin 1,2-ditricosa-10,12-diynoyl-sn-glycero-3-phosphocholine and its saturated analogue, 1,2-ditricosanoyl-sn-glycero-3-phosphocholine, has been investigated by wide- and low-angle X-ray diffraction of both powder and oriented samples and by differential scanning calorimetry. Previous studies have shown that the hydrated diacetylenic lipid forms novel microstructures (tubules and stacked bilayer sheets) in its low-temperature phase. The diffraction results indicate that at low temperatures fully hydrated tubules and sheets have an identical lamellar repeat size (d001 = 66.4 A) and crystalline-like packing of the acyl chains. Chain packing in the lamellar crystalline phase is hydration independent. A model for the polymerizable lecithin with (1) fully extended all-trans methylene segments, (2) a long-axis tilt of 32 degrees, and (3) minimal chain interdigitation seems most reasonable on energetic grounds, is consistent with the diffraction data (to 3.93-A resolution), and is likely to support facile polymerization. Above the chain "melting" transition the lamellar repeat of the polymerizable lipid increases to 74 A. The conformational similarity between tubules, sheets, and the dry powder is corroborated by calorimetry, which reveals a cooling exotherm at the same temperature where tubules form upon cooling hydrated sheets. The data suggest that although a high degree of conformational order is a pertinent feature of tubules, this character alone is not sufficient to account for tubule formation. The conformation of the corresponding saturated phosphatidylcholine appears to be similar to that of other saturated phosphatidylcholines in the lamellar gel phase. Furthermore, above the main transition temperature, the dry, saturated lipid shows evidence of a P delta phase (112 degrees C), whereas the diacetylenic lipid appears to exhibit a centered rectangular phase, R alpha (55 degrees C).
1,2-Dipalmitoylphosphatidylcholine↗
Response to heparin in patients with ulcerative colitis.
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Adult↗
A database of lipid phase transition temperatures and enthalpy changes.
The systematic study of the mesomorphic phase properties of synthetic and biologically derived lipids began some 30 years ago. In the past decade, interest in this area has grown enormously. As a result, there exists a wealth of information on lipid phase behavior, but unfortunately these data have, until now, been scattered throughout the literature in a variety of books, proceedings and journals. The data have recently been compiled in a centralized database with a view to providing ready access to same and to the appropriate literature. The compilation facilitates review of what has thus far been accomplished and highlights what remains to be done in this active research area. As such, it represents a convenient summary of the existing data which, when evaluated, will enable us to identify where deficits exist in the data, to reveal the fundamental physicochemical principles upon which lipid phase behavior is based and to understand more completely lipid phase relations in biological, reconstituted and formulated systems. The compilation consists of a tabulation of all known mesomorphic and polymorphic phase transition temperatures and enthalpy changes for synthetic and biologically-derived lipids in the dry and in the partially and fully hydrated states. Also included is the effect on these thermodynamic values of pH, and of salt and metal ion concentration and other additives such as proteins, drugs, etc. The methods used in making the measurements and the experimental conditions are reported. Bibliographic information includes complete literature referencing and list of authors. As of this writing, the database is current through June, 1990 and contains in excess of 9500 records. Each record contains 28 fields. Here, we describe how the database originated, its scope and contents, data abstraction procedures, and issues relating to mesophase and lipid nomenclature, data analysis and evaluation, and database maintenance and distribution.
Databases, Factual↗