Measurement of the extraction efficiency and distribution volume for Gd-DTPA in normal and diseased canine myocardium

We have previously shown that the myocardial Gd-DTPA concentration ([Gd-DTPA]t(t)) after a bolus injection of Gd-DTPA can be predicted by the Modified Kety Equation (MKE). If [Gd-DTPA]t(t) can be determined by MRI and the data fit to the MKE, then the distribution volume (lambda) of Gd-DTPA and the myocardial flow (F) times the extraction efficiency (E), i.e., the FE product, can be determined. Therefore F can only be quantified if E is known. We measured the global E in vivo in normal canine myocardium, and measured E and lambda, in vitro, locally in normal, acute ischemic (n = 5; coronary artery occlusion < 4 h), infarcted (n = 4; coronary artery occlusion, 6 days) and reperfused (n = 4; coronary artery occlusion 2 h, and reperfusion 2 h and 6 days) myocardium. Results indicate that E differs with F and with individuals and consequently, F cannot be quantified using the MKE unless the local E is also determined in vivo.

Techniques for the measurement of the local myocardial extraction efficiency for inert diffusible contrast agents such as gadopentate dimeglumine

We have previously shown that the concentration of Gd-DTPA as a function of time ([Gd-DTPA]t(t)) in the myocardium following an intravenous bolus injection of Gd-DTPA can be modeled using the Modified Kety Equation. Fitting this model to measurements of [Gd-DTPA]t(t) in a region of myocardium would allow the determination of myocardial distribution volume (lambda) and the product of flow (F) and extraction efficiency (E), i.e., FE. Thus, to measure F, E must be known. We describe here techniques developed to measure local values of E in normal and diseased myocardium. These techniques are valid for any inert diffusible MR contrast agent.

Injury prevention instruction in the emergency department

STUDY OBJECTIVE

To describe preventable pediatric injuries and the proportion receiving documented injury prevention instruction by emergency department personnel.

DESIGN

Retrospective chart review.

SETTING

A rural Level I trauma center.

TYPES OF PARTICIPANTS

All injured children aged birth through 15 years presenting to our hospital from January 1, 1987, through December 31, 1987.

MEASUREMENTS AND MAIN RESULTS

During the study period, 1,449 injuries presented to the trauma center. Motor vehicle crashes caused the largest number of preventable injuries (71), although the proportion of preventable injuries was higher among poisonings, burns, and pedestrian-automobile collisions. Among the 1,313 patients available to ED personnel at discharge, injury prevention instruction was indicated in 27% of cases but documented in the medical record in only 3%. ED personnel were more likely to document instruction for preventing poisoning than other causes of injury.

CONCLUSION

Most preventable pediatric injuries treated and released by ED personnel do not receive documented injury prevention instruction.

Swedish austerity: benefits at risk

The Swedish welfare state is facing the greatest threat since its inception. Attacks stem from the country's sharp economic downturn since 1989 and the related currency crisis of September 1992. Politicians of the right and left have responded to the economic crisis by initiating cutbacks in social welfare programs and supporting policies that will lead to a massive transfer of income from working people to corporations. The focus on cutting social programs is misplaced. The Swedish economy flourished for decades with the network of social service programs in place; the welfare state cannot be blamed for economic problems that have only recently arisen.

Platelet storage results in a redistribution of glycoprotein Ib molecules. Evidence for a large intraplatelet pool of glycoprotein Ib

Platelet membrane glycoprotein (GP) Ib contains receptor for von Willebrand factor and thrombin. Its proteolytic fragment, glycocalicin, circulates in normal plasma. In this study, storage of platelet concentrates for 5 d resulted in a 221% increase in plasma glycocalicin (1.3 times the total amount of glycocalicin present on the surface of all platelets), an 8% overall increase in platelet surface GPIb, and the appearance of a surface GPIb-negative subpopulation of platelets. Total platelet GPIb content of fresh washed platelets, determined by gel electrophoresis and immunoassay of Triton X-100 lysates, averaged 159,740 molecules per platelet. There were 36,360 surface GPIb molecules per platelet, determined by immunoassay of the supernatant of fresh washed platelets whose surface GPIb had been completely plasmin-cleaved. In summary, these studies provide evidence for (a) a redistribution of GPIb molecules with platelet storage, and (b) a large intraplatelet pool of GPIb (approximately threefold larger than the platelet surface pool of GPIb).

Inhibition of rabbit beta-globin synthesis by complementary oligonucleotides: identification of mRNA sites sensitive to inhibition

We tested the effects of a series of synthetic oligonucleotides (hybridons) complementary to the 5' noncoding and coding regions of rabbit beta-globin mRNA on endogenous protein synthesis in a rabbit reticulocyte cell-free translation system. With highly purified hybridons inhibition was completely specific for beta-globin. The sites most sensitive to inhibition are the beginning of the 5' noncoding region and a sequence including the initiation codon and several upstream bases. The region between these was relatively insensitive to inhibition. The sites of maximum sensitivity coincide with known protein binding sites, suggesting that hybridons exert their effects in part by blocking the binding of proteins required for translation. Their effectiveness seems related to the ease with which they are displaced by ribosomes.

The shortages of nurses in NSW: a motivation hygiene approach to identifying problems and solutions

For a number of years public hospitals in NSW have experienced high turnover figures for nursing staff and have been unable to recruit sufficient numbers of registered nurses back into hospital employment. This paper outlines factors on both the demand and the supply side which contribute to the present shortage. It then goes on to argue that a greater appreciation of the causes of the shortage, and strategies for its resolution, can be gained by presenting the issues from the perspective of Herzberg's Motivation--Hygiene Theory. 'Motivation' factors, providing satisfaction to nurses, include achievement and recognition, the work itself, responsibility, advancement and potential for personal growth. 'Hygiene' factors, producing dissatisfaction, include physical working conditions, employer policies and administrative practices, interpersonal relations, salary. Discussion of the issues from this perspective indicates that strategies to resolve the crisis must proceed on two fronts. Continuing efforts must be made to promote job satisfaction among nurses while at the same time reducing the incidence of factors promoting job dissatisfaction.

Reconstitution of functional mRNA-protein complexes in a rabbit reticulocyte cell-free translation system

A variety of evidence suggests that the cytoplasmic mRNA-associated proteins of eucaryotic cells are derived from the cytoplasm and function there, most likely in protein synthesis or some related process. Furthermore, the evidence suggests that protein-free mRNA added to a cell-free translation system should become associated with a set of proteins similar to those associated with mRNA in native polyribosomes. To test this hypothesis, we added deproteinized rabbit reticulocyte mRNA to a homologous cell-free translation system made dependent on exogenous mRNA by treatment with micrococcal nuclease. The resulting reconstituted complexes were irradiated with UV light to cross-link the proteins to mRNA, and the proteins were analyzed by gel electrophoresis. The proteins associated with polyribosomal mRNA in the reconstituted complexes were indistinguishable from those associated with polyribosomal mRNA in intact reticulocytes. Furthermore, reticulocyte mRNA-associated proteins were very similar to those of cultured mammalian cells. The composition of the complexes varied with the translational state of the mRNA; that is, certain proteins present in polyribosomal mRNA-protein complexes were absent or reduced in amount in 40S to 80S complexes and in complexes formed in the absence of translation. However, other proteins, including a 78-kilodalton protein associated with polyadenylate, were present irrespective of translational state, or else they were preferentially associated with untranslated mRNA. These findings are in agreement with previous data suggesting that proteins associated with cytoplasmic mRNA are derived from the cytoplasm and that they function in translation or some other cytoplasmic process, rather than transcription, RNA processing, or transport from the nucleus to the cytoplasm.

Inverted papilloma of the nasal septum

Inverted papillomas are primarily lesions of the lateral nasal wall, but similar papillomas have been observed on the nasal septum. There is controversy as to whether papillomas on the septum should be considered differently from those of the lateral nasal wall and paranasal sinuses. A review of the records of the Massachusetts Eye and Ear Infirmary, Boston, disclosed 18 cases of inverted papilloma of the nasal septum that were treated before January 1968 and January 1980. The histologic diagnosis of inverted papilloma was confirmed by pathologists who examined histologic slides from these cases; these slides had been randomly mixed with slides of nasal vestibule squamous papillomas and slides of inverted papillomas of the lateral nasal wall. Squamous papillomas of the vestibule were readily distinguished microscopically from inverted papillomas of the septum and lateral wall that were histologically similar. The clinical course of these patients suggests that inverted papillomas of the nasal septum behave like inverted papillomas elsewhere and require wide surgical excision and careful follow-up.

DNA polymerase: evidence for multiple molecular species

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