Double analog transition 14C( pi +, pi -) 14O at 50 MeV.
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Journal Article↗
Biomedical subjects
D Roberts
Publications and source records attributed to D Roberts.
Endogenous lectins in normal and dystrophic muscle development.
Two endogenous lectin activities, one specific for beta-D-galactose (beta-D-Gal) residues and purified on asialofetuin-Sepharose and the second specific for iduronic acid containing glycosaminoglycans and purified on heparin-Sepharose, have been studied during myogenesis in both normal and dystrophic chickens. The Storrs strain, homozygous for muscular dystrophy, and the dystrophic strain 413 from the University of California at Davis were both used in this study. Strain 412 and local hatchery chickens were used as controls. The lectins derived from all sources appeared to be identical based on physical properties and carbohydrate specificity. Both normal and dystrophic adult chickens possessed similar lectin levels in lung, spleen, kidney, heart, and muscle tissue. No differences were noted in the temporal appearance of the heparin-binding lectin; however, the beta-D-Gal-binding lectin appeared earlier in the Storrs dystrophic strain than it did in the 413, 412, or hatchery embryos.
Animals↗
Magnetic resonance imaging of the temporomandibular joint meniscus.
This report describes early experience with magnetic resonance imaging (MRI) of the temporomandibular joint meniscus in which surface coil technology was used. The results suggest remarkable imaging capabilities and speed with noninvasive methods.
Cartilage, Articular↗
Identification of an anteriorly displaced meniscus in vitro by means of three-dimensional image reconstructions.
Computerized tomography has some limitations for diagnosis of internal derangements of the TMJ. The use of three-dimensional image reconstructions of CT data may enhance the diagnostic utility of CT. In a cadaver simulation, three-dimensional imaging was able to demonstrate the location of a displaced meniscus which was not obvious in two-dimensional sections. Location of the meniscus was aided by the use of a "transparency mode" in displaying the data.
Cartilage, Articular↗
IS10 transposition is regulated by DNA adenine methylation.
We show that dam- mutants are a major class of E. coli mutants with increased IS10 activity. IS10 has two dam methylation sites, one within the transposase promoter and one within the inner terminus where transposase presumably binds. Absence of methylation results in increased activity of both promoter and terminus, and completely accounts for increased transposition in dam- strains. Transposition of Tn903 and Tn5 are also increased in dam- strains, probably for analogous reasons. Transposition is also increased when IS10 is hemimethylated. One hemimethylated species is much more active than the other and is estimated to be at least 1000 times more active than a fully methylated element. Evidence is presented that the promoter and inner terminus of IS10 are coordinately activated in a dam-dependent fashion, presumably because they are hemimethylated at the same time. Thus, in dam+ strains, IS10 will transpose preferentially when DNA is hemimethylated. We suggest specifically that IS10 transposition may preferentially occur immediately after passage of a chromosomal replication fork.
Adenine↗
The financial impact of a comprehensive adolescent pregnancy program on a university hospital.
This study investigated the financial impact which an adolescent pregnancy program had on one of its sponsoring agencies, the University Hospital, Salt Lake City, UT. Financial data from hospital billings and collections on the 75 teens who delivered during a 12-month period were reviewed. A comparison of the money for salaries supplied to the special program by the hospital with the amount of estimated "new" money generated for the hospital by the program yielded an income to expenditure ratio greater than two. Eighteen teens who were in the lowest self-pay category were matched to self-pay teens delivering at the same hospital who received traditional prenatal care. The hospital collection rate for teens in the special program was not significantly greater than that of the comparison group. The investment in an adolescent pregnancy program was beneficial mainly from the viewpoint of recruitment of patients who were brought into the hospital system as a result of the adolescent pregnancy program.
Accounting↗
Microbiological aspects of goat's milk. A Public Health Laboratory Service survey.
In a 12-month survey (June 1982-May 1983) 41 laboratories examined 2493 samples of goat's milk for colony counts and the presence of pathogens. The statutory tests for cow's milk were also applied. Surface counts of less than 10(5) organisms per ml of raw milk were given by 79% of samples at 37 degrees C and by 76% at 22 degrees C. There were less than 100 coliforms per ml in 71% of samples, less than 10 Escherichia coli per ml in 91%. Staphylococcus aureus was not detected in countable numbers in 96% of samples. Only one isolation of campylobacter was made and two of Yersinia enterocolitica. Salmonella was not detected in 2462 samples. The methylene blue test was carried out on 2368 samples and 86.7% were deemed satisfactory. No sample was Brucella ring-test-positive. Experiments on the survival and growth of six food poisoning organisms in stored goat's milk showed that Bacillus cereus, Staph. aureus, Salmonella typhimurium and Y. enterocolitica survived quite well and multiplied at the higher storage temperature of 30 degrees C. Clostridium perfringens only increased 10- to 100-fold while Campylobacter jejuni did not grow. The results of the survey indicate that any problems with goat's milk relate to poor hygiene during production rather than transmission of organisms from the goat herself.
Animals↗
Collaborative study on the isolation of salmonella from artificially contaminated milk powder.
The suitability of artificially contaminated milk powder as a substrate for salmonella reference samples and its stability under different storage conditions were studied. The need for a reconstitution step in the standard isolation method for salmonellas from milk powders was also investigated. When milk powder was examined in this way with a reconstitution step, differences in laboratory methods and/or storage times had no significant effect on the results after storage at 4 degrees C. With powder stored at room temperature there was a systematic decrease in the number of samples positive as the storage time increased. It is concluded therefore that milk powder contaminated with salmonellas should be stored at 4 degrees C. Examination of such milk powder with a reconstitution step yielded better results than without it and this step is therefore necessary for improving the reproducibility of the method. No significant differences were encountered between the standard isolation method and that used in the authors' laboratories. The results of this study indicate that milk powder is suitable as basic material for reference samples and that a reconstitution step should be included in the standard salmonella isolation procedure.
Animals↗
Effect of bacterial products on human ciliary function in vitro.
Ciliary activity protects the respiratory tract against inhaled particles, including bacteria, by transporting them trapped in mucus towards the pharynx. We have studied the effect of bacteria (Haemophilus influenzae, Staphylococcus aureus, and Pseudomonas aeruginosa) on human nasal cilia, measuring their in vitro ciliary beat frequency by a photometric technique. Supernatant fluids were obtained from 18 hour broth cultures by centrifugation alone, by filtration, and by lysis. Supernatants obtained from Ps aeruginosa and H influenzae caused a significantly lower ciliary beat frequency than controls (broth alone). Slowed cilia were dyskinetic and at times of maximal slowing ciliostasis occurred in some areas of the epithelium. A dose related effect was demonstrated. Abrogation of cilioinhibitory properties was achieved by heating the lysate to 56 degrees C for 30 minutes and by allowing the filtrate to stand at 37 degrees C for 120 minutes. Staphylococcal products were not cilioinhibitory. It is concluded that Ps aeruginosa and H influenzae release a factor (or factors) which causes slowing of human nasal cilia in vitro. The role of this factor in the pathogenesis of infection is discussed.
Cilia↗
Temporomandibular joint: magnetic resonance imaging.
Magnetic resonance (MR) imaging of the temporomandibular joint was performed in two subjects using a 1.5 T experimental imaging system equipped with a 6.5 cm surface coil antenna. Normal and pathologic anatomy were demonstrated with exquisite detail. Anterior displacement of the joint meniscus was clearly visible in the symptomatic subject, consistent with arthrographic confirmation.
Adult↗
Surgical removal of pulmonary metastases from renal cell carcinoma.
Thirty-three patients operated on for pulmonary metastases from renal cancer were followed up for a minimum of 5 years or to death. The 5-year survival was 21%. There was a tendency to better survival in patients operated by lobectomy rather than limited resection. Extended operations carried a grave prognosis. Manifest metastatic disease within one year after the primary operation showed shortened survival. Repeated operations were possible, with good results. It is concluded that operations for pulmonary metastases can be performed with good results. However, the effect is a palliative one as the ultimate cause of death in all instances was the spread of the cancer disease.
Carcinoma, Renal Cell↗
Mechanical trauma to red blood cells caused by Björk-Shiley and Carpentier-Edwards heart valves.
The haemolytic properties of mechanical and biologic valve prostheses are well established, and it is known that they can shorten red cell survival time (1, 2). Their effects on red cell deformability are not known, however. A comparative study was therefore made of two valve types--Björk-Shiley (BS) and Carpentier-Edwards (CE). Thirty-nine patients with normally functioning valve prostheses (23 BS, 16 CE) were studied at least one year after surgery, by assessing red cell deformability measured as red cell filtration rate (RFR), red cell survival half-time with the Cr-51 isotope method (Cr-51 T1/2) and plasma-haemoglobin (P-Hb). The BS valve was shown to be more traumatic to the cells than the CE valve and effected greater reduction of the deformability of these cells. Significant intercorrelations were found between RFR, CR-51 T1/2 and P-Hb.
Aortic Valve↗
Changes in red cell deformability associated with anaesthesia and cardiopulmonary bypass in open-heart surgery.
Red cell deformability was observed during open-heart surgery in 59 patients. Deformability, assessed with a standard microfiltration method, was expressed as red cell filtration rate (RFR) in microliter/s. The mean preoperative value, 38.9 +/- 1.0 microliter/s, showed a generally falling tendency. The first significant decrease in mean RFR (by 18%) followed induction of general anaesthesia, and the second (by 15%) was seen 60 min after the start of cardiopulmonary bypass (CPB). The major decrease in RFR during CPB was found at the end of bypass, when it was reduced to 62% of the pre-CPB value. The percentage RFR reduction at the end of CPB showed significant correlation with 1) CPB duration (r = 0.49), 2) oxygen flow rate index (OFRI), i.e. flow/min in the bubble oxygenator/m2 bsa (r = 0.38), and 3) blood flow rate index (BFRI), i.e. average volume of blood pumped through the heart-lung machine/min CPB time/m2 bsa (r = 0.51).
Age Factors↗
Evaluation of red cell damage during cardiopulmonary bypass.
In patients undergoing cardiopulmonary bypass (CPB), red cell damage was assessed by simultaneous measurement of of plasma-haemoglobin (P-Hb) and red cell filtration rate (RFR) (1). RFR was significantly reduced after 120 min as compared with 30 min (17.4 +/- 4.1 vs. 30.4 +/- 2.9 microliters/s). P-Hb, by contrast, was significantly higher at 60 min than at 30 min after start of CPB (195 +/- 27.2 vs. 73.8 +/- 8.1 microliters/s). Significant negative correlation was found between RFR and P-Hb (r = 0.68). Red cell deformability thus permitted qualitative assessment of red cell trauma during CPB and thereby an estimation of the rheologic disturbance caused to these cells by CPB during open-heart surgery.
Cardiopulmonary Bypass↗
Improved red blood cell survival after cardiac operations with administration of urea during cardiopulmonary bypass.
The plasma hemoglobin and red blood cell survival (half-life of 51Cr) was studied in 48 patients undergoing single valve replacement or coronary artery bypass graft. Urea or placebo was administered during cardiopulmonary bypass in a prospective, randomized, double-blind manner to test the potential effect on mechanical hemolysis. The mean plasma hemoglobin level at the end of extracorporeal circulation was significantly lower in the urea-treated groups (coronary artery bypass 342 mg/L; valve replacement 364 mg/L) than in the control groups (coronary artery bypass 635 mg/L, p less than 0.05; valve replacement 518 mg/L, p less than 0.01). The half-life of 51Cr was significantly longer in the urea-treated patients (coronary artery bypass 18 days; valve replacement 16 days) than in the control groups (coronary artery bypass 12.4 days, p less than 0.01; valve replacement 12.7 days, p less than 0.001) but still below the normal reference value (29 +/- 4 days). The plasma hemoglobin returned to near normal values (50 mg/L) the day after operation (day 1) and remained low with no differences between control and urea-treated groups. The total blood hemoglobin was followed for 2 weeks after operation and showed significantly less anemia in the urea-treated group. The lowest mean blood hemoglobin level was noted between days 5 and 9-114 (coronary artery bypass) and 107 (valve replacement) gm/L in the urea-treated patients compared to 92.3 (coronary artery bypass, p less than 0.01) and 92.2 (valve replacement, p less than 0.01) gm/L in the control subjects. The reduction in the severity of the anemia led to less transfusion in the urea-treated patients (approximately 0.5 unit/patient) than in the control subjects (approximately 1 unit/patient, p less than 0.05) between days 3 and 14.
Blood Transfusion↗
Isolation of spheroplastic forms of Haemophilus influenzae from sputum in conventionally treated chronic bronchial sepsis using selective medium supplemented with N-acetyl-D-glucosamine: possible reservoir for re-emergence of infection.
The isolation rate of Haemophilus influenzae from patients with persistent production of purulent sputum has been increased by the routine use of a selective medium. Nevertheless, some purulent sputum still fails to yield a pathogen. The selective medium was supplemented with N-acetyl-D-glucosamine to encourage primary isolation of colony forming, spheroplastic H influenzae, which reverted to normal forms on subculture. On the basis of in vitro experiments it is postulated that these spheroplastic forms of H influenzae may be induced by inadequate antimicrobial chemotherapy and may be responsible for re-emergence of symptoms in these patients during or shortly after stopping chemotherapy.
Acetylglucosamine↗
Structure of the gene encoding the immunodominant surface antigen on the sporozoite of the human malaria parasite Plasmodium falciparum.
The gene for the circumsporozoite (CS) protein of Plasmodium falciparum has been cloned and its nucleotide sequence determined. The gene encodes a protein of 412 amino acids as deduced from the nucleotide sequence. The protein contains 41 tandem repeats of a tetrapeptide, 37 of which are Asn-Ala-Asn-Pro and four of which are Asn-Val-Asp-Pro. Monoclonal antibodies against the CS protein of Plasmodium falciparum were inhibited from binding to the protein by synthetic peptides of the repeat sequence. The CS protein of Plasmodium falciparum and the CS protein of a simian malaria parasite, Plasmodium knowlesi, have two regions of homology, one of which is present on either side of the repeat. One region contains 12 of 13 identical amino acids. Within the nucleotide sequence of this region, 25 of 27 nucleotides are conserved. The conservation of these regions in parasites widely separated in evolution suggests that they may have a function such as binding to liver cells and may represent an invariant target for immunity.
Amino Acid Sequence↗
Direct visualization of the coronary microcirculation for pharmacologic and physiologic studies.
An isolated, arrested rat heart preparation which has coronary tone similar to that found in vivo and allows direct visualization of the coronary microcirculation is described. The rat hearts are perfused in situ prior to isolation. This procedure obviates any ischemic ischemic damage to the heart. The perfusate used is a modified Krebs solution with 40 mM potassium, 2 g% albumin, and washed red cells (20% HCT). To directly view the coronary microcirculation, a fluorescent albumin conjugate is added to the cell-rich perfusate. The epicardial microvessels are illuminated and observed with a fluorescence microscope. It was found that the control intercapillary distance in this model (33 microns) was almost twice that reported by other investigators for working hearts and suggested a 60-70% coronary capillary reserve in the arrested heart. The calcium blocker nisoldipine (Miles Laboratories) caused a dose-dependent coronary vasodilation using either a constant-flow or constant-pressure protocol. The coronary reactivity of this preparation to nisoldipine was 50 times greater than reported for isolated hearts perfused with cell-free Krebs solution. Further, the preparation vasodilated in a dose-dependent manner to histamine, but histamine did not cause a significant increase in coronary permeability to macromolecules. This model is appropriate for both physiologic and pharmacologic studies. It is particularly well suited for determining the direct effects of an intervention on coronary tone and the coronary microcirculation.
Animals↗