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Biomedical subjects

M Foley

Publications and source records attributed to M Foley.

At least 55 records · Page 3Linked to original sources

Pulmonary embolism after hip or knee replacement: postoperative changes on pulmonary scintigrams in asymptomatic patients.

Serial pulmonary imaging has proved to be effective in the evaluation of patients undergoing total joint arthroplasty. A clinical dilemma arises in asymptomatic patients whose postoperative pulmonary images differ from the preoperative images. The authors prospectively evaluated 403 patients with serial imaging to determine the significance of changed postoperative images in asymptomatic patients undergoing total hip or knee arthroplasty. Twenty-two (5.5%) patients had significant changes on postoperative images. Seventeen were asymptomatic; all but one underwent pulmonary angiography. Documented pulmonary emboli were demonstrated in 100% of patients whose postoperative images changed to indicate a high probability of pulmonary embolism, 71% whose images changed to a moderate probability, and 0% whose images changed to indeterminate probability. Overall, pulmonary emboli occurred in 76% of all asymptomatic patients with significantly change postoperative images. Asymptomatic pulmonary embolism is a significant occurrence after total hip or knee repair, and a changed lung scan with appropriate clinical evaluation is an accurate indicator of pulmonary emboli in asymptomatic postarthroplasty patients.

Adult

Articulated needle guide: report on the first 30 cases.

This report represents our initial experience with a new type of needle guide for amniocentesis, transabdominal chorionic villus biopsies, and funipuncture developed at the Ohio State University and tested at the Harris Birthright Centre for Fetal Medicine. This articulated needle guide is designed to combine the advantages of the existing needle guides and the freehand technique. The needle guide offers improved maneuverability compared with standard needle guides and maintains easy visualization of the needle.

Amniocentesis

Cesarean section and perinatal outcome: response from the House of Horne.

A direct comparison between Parkland Memorial Hospital in Dallas, Texas, and the National Maternity Hospital in Dublin, Ireland, on the basis of limited numbers taken from one year only (1983) led to the conclusion that the liberal use of cesarean section in Dallas was associated with a sevenfold decrease in intrapartum fetal deaths and a twofold decrease in neonatal seizures. However, when the scope of the survey is extended to include the year before (1982) and the year after (1984), a different picture emerges. During this extended period there were almost four times as many cesarean sections performed in Dallas with no significant difference in overall perinatal mortality, while for two of three years the incidence of neonatal seizures was twice as high in Dallas when compared with Dublin. The fact that high cesarean rates continue to rely on evidence of such a tenuous nature must remain a matter of concern.

Adult

Changes in the organization of the surface membrane upon transformation of cercariae to schistosomula of the helminth parasite Schistosoma mansoni.

Merocyanin 540 (Mc540) is a fluorescent compound which is thought to bind to membranes in which there are substantial amounts of lipid in the lipid-crystalline phase. It is shown here to be of value in detecting the transformation by both mechanical and skin-penetration methods of the cercaria to the schistosomulum. The cercaria does not appear to bind Mc540, but the schistosomulum, binds Mc540 initially, in its anterior region, and at later times over the entire surface. The suggestion that transformation involves changes in the surface membrane lipid phase from gel to liquid-crystalline phase is supported by fluorescence recovery after photobleaching results with 5-N-(octadecanoyl)-amino fluorescein, a lipophilic dye which appears to be immobile in the cercaria, but fully mobile in the 40 min schistosomulum.

Animals

Biophysical properties of the surface lipid of parasitic nematodes.

The biophysical properties of the surface lipid layer (the epicuticle) of living parasitic nematodes (Trichinella spiralis and Toxocara canis) were examined using fluorescent lipid analogues. A variety of such probes were screened, and only 5-N-(octadecanoyl)-aminofluorescein was found to insert into the outer lipid layer. Fluorescence quenching experiments showed that this probe was confined to the surface, and the rate of its lateral diffusion was then measured by Fluorescence Recovery After Photobleaching. This showed that the probe was not free to diffuse within the plane of the epicuticle. This structure is, therefore, extraordinary in its selectivity to lipid probes, and in the restricted lateral mobility of inserted lipid components.

Animals

Granulocytopenia complicating colchicine therapy for primary biliary cirrhosis.

A case is presented of a 76-yr-old woman with primary biliary cirrhosis and adult polycystic liver disease who developed bone marrow toxicity associated with chronic low-dose colchicine therapy. Two months after starting colchicine therapy (0.6 mg b.i.d. p.o.), the patient developed hematologic toxicity as evidenced by transient but profound granulocytopenia which promptly reversed 4 days after the drug was stopped. Bone marrow examination revealed moderate hypocellularity of all cell lines and striking dysplastic changes in the late myeloid and erythroid series. There was no apparent toxicity involving other organ systems. The patient fully recovered. This case is compared with previous descriptions of colchicine toxicity.

Aged

The lateral diffusion of lipid probes in the surface membrane of Schistosoma mansoni.

The technique of fluorescence recovery after photobleaching was used to measure the lateral diffusion of fluorescent lipid analogues in the surface membrane of Schistosoma mansoni. Our data reveal that although some lipids could diffuse freely others exhibited restricted lateral diffusion. Quenching of lipid fluorescence by a non-permeant quencher, trypan blue, showed that there was an asymmetric distribution of lipids across the double bilayer of mature parasites. Those lipids that diffused freely were found to reside mainly in the external monolayer of the outer membrane whereas lipids with restricted lateral diffusion were located mainly in one or more of the monolayers beneath the external monolayer. Formation of surface membrane blebs allowed us to measure the lateral diffusion of lipids in the membrane without the influence of underlying cytoskeletal structures. The restricted diffusion found on the normal surface membrane of mature parasites was found to be released in membrane blebs. Quenching of fluorescent lipids on blebs indicated that all probes were present almost entirely in the external monolayer. Juvenile worms exhibited lower lateral diffusion coefficients than mature parasites: in addition, the lipids partitioned into the external monolayer. The results are discussed in terms of membrane organization, cytoskeletal contacts, and biological significance.

Animals

Lateral diffusion of proteins in the periplasm of Escherichia coli.

We have introduced biologically active, fluorescently labeled maltose-binding protein into the periplasmic space of Escherichia coli and measured its lateral diffusion coefficient by the fluorescence photobleaching recovery method. Diffusion of this protein in the periplasm was found to be surprisingly low (lateral diffusion coefficient, 0.9 X 10(-10) cm2 s-1), about 1,000-fold lower than would be expected for diffusion in aqueous medium and almost 100-fold lower than for an equivalent-size protein in the cytoplasm. Galactose-binding protein, myoglobin, and cytochrome c were also introduced into the periplasm and had diffusion coefficients identical to that determined for the maltose-binding protein. For all proteins nearly 100% recovery of fluorescence was obtained after photobleaching, indicating that the periplasm is a single contiguous compartment surrounding the cell. These data have considerable implications for periplasmic structure and for the role of periplasmic proteins in transport and chemotaxis.

ATP-Binding Cassette Transporters

Lumbar myelography with metrizamide in rabbits. An investigation of contrast media penetration and resorption.

Neurotoxicity from subarachnoid contrast media is probably related to their specific pharmacologic effects and to their penetration into the central nervous system. The lack of a barrier between the cerebrospinal fluid and the extracellular fluid of the brain and cord allows water-soluble contrast media to diffuse into the neural tissue. The aim of this investigation was to develop a method that allows one to quantify the neural tissue penetration for a given contrast medium in relation to the cerebrospinal fluid concentration and contact time and apply this to the use of metrizamide. The result shows a good correlation between iodine concentration in the lumbar cerebrospinal fluid and that in the lumbar cord suggestive of a simple diffusion. When time of sacrifice (contact time) is added as a covariant there is also some indication of retention of metrizamide in the neural tissue. The investigation also demonstrates that the resorption of the contrast medium in the rabbit in this experimental model is mainly in the lumbo-sacral region.

Animals

Active management of labor as an alternative to cesarean section for dystocia.

There is general agreement that a solution to the problem of dystocia would go a long way toward resolving the contentious issue of high cesarean birth rates that have become such a prominent feature of obstetric practice in recent years. At the National Maternity Hospital in Dublin, one of the largest obstetric units in Western Europe, this situation has been averted through a coordinated policy of early detection and effective treatment of abnormal uterine action over a period of 15 years. During 1980 the number of births was 8742, the incidence of cesarean section was 4.8%, and mothers were assured of delivery within 12 hours after admission to the labor unit. It is proposed that these results could be reproduced elsewhere.

Adult

Correlation of decrease in perinatal mortality and increase in cesarean section rates.

During what has proved to be a critical period in the practice of modern obstetrics, 1965 to 1980, when cesarean birth rates increased dramatically in centers across the United States from less than 5 to more than 15%, the number of infants born in the National Maternity Hospital, Dublin, was 108,987. Although the incidence of cesarean section remained virtually unchanged at 4.2, 4.2, 4.2, and 4.8% in 1965, 1970, 1975, and 1980, respectively, perinatal mortality continued to fall from 42.1 to 36.5, 24.0, and 16.8 per 1000 infants born at 500 g or more. These results do not support the contention that the expansion in cesarean birth rates has contributed significantly to reduced perinatal mortality in recent years. Consideration of indications shows that the threefold difference in cesarean birth rate which now exists between Dublin and similar centers across the United States can be accounted for almost entirely by a different approach to management of labor in nulliparous women, compounded by rigid adherence to precept "once a section, always a section.

Cesarean Section