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Biomedical subjects

D Seligson

Publications and source records attributed to D Seligson.

At least 109 records · Page 6Linked to original sources
PubMed1985

In vitro characteristics of tobramycin-PMMA beads: compressive strength and leaching.

Antibiotic-impregnated polymethylmethacrylate (PMMA) bone cement beads have been used as a local drug delivery system for the treatment of bone and soft tissue infections. The beads deliver a high local level of antibiotic with a decreased risk of toxic systemic levels. This study was undertaken to determine the antibiotic release characteristics of tobramycin-impregnated beads over time and to determine the compressive strength of these beads. Acrylic resin (PMMA) bone cement beads were prepared with three different concentrations of tobramycin. The beads were tested for compressive strength, and their antibiotic release characteristics were determined over a 21 day period by radioimmunoassay and by biological testing against a variety of bacteria. The compressive strength of the beads was found to be adequate to avoid fragmentation during their clinical use. There was gradual release of tobramycin from the beads over the entire 21 days, but the release was most marked during the first 48 hours. There was antibiotic activity against both gram-negative and gram-positive organisms, except Enterococcus, for the entire 21 day period. The release of tobramycin followed a curvilinear relationship and was directly related to the initial antibiotic concentration of the bead. Tobramycin-impregnated polymethylmethacrylate beads may represent a reliable method of local antibiotic delivery with sustained activity against a broad spectrum of organisms.

Bone Cements↗
PubMed1985

An anion-exchange chromatographic method for measuring bilirubin covalently bound to albumin.

After alkalinizing the diazo products of serum bilirubins, we apply them to a column of anion-exchange resin. The azodipyrroles derived from unconjugated and sugar-conjugated bilirubins, as well as from one half of the tetrapyrrole covalently linked to albumin ("Bil-Alb"), are anionic and protein-free and adsorb to the resin. The other half of the azo product of Bil-Alb, with absorptivity similar to that of the protein-free azodipyrroles, remains attached to albumin (Clin Chem 28:629-637, 1982) and passes through the resin unadsorbed. The color of the eluate correlates directly with the original amount of Bil-Alb present. Estimates of authentic Bil-Alb by the method agree with those by a Jendrassik-Gróf total-bilirubin method (in mg/L: intercept = -0.8, slope = 1.005, r = 0.999) and by liquid chromatography (Clin Chem 29:800-805, 1983) (n = 52, intercept = 5.2, slope = 0.724, r = 0.965). The CV of the method for serum with Bil-Alb of 99.4 mg/L was 3.8% (n = 8).

Animals↗
PubMed1984

Irreversible binding of conjugated bilirubin to albumin in cholestatic rats.

A diazo-positive fraction of serum bilirubin that is irreversibly bound to albumin has been shown to accumulate in serum of patients with cholestasis. In the present study, a cholestatic animal model was used to determine the chemical nature of the bilirubin species involved in its formation. The data indicate that conjugated bilirubin is the precursor of "albumin-bound bilirubin" and that the presence or absence of light does not affect its formation. An albumin-bound bilirubin-complex indistinguishable from the complex detected in cholestatic sera from patients or in bile duct-ligated Sprague-Dawley rats can be formed in vitro in sera enriched in conjugated bilirubin at 37 degrees C, pH 7.4.

Animals↗
PubMed1984

Diazo-based assay for total bilirubin in a coated thin film evaluated.

We compared results for total bilirubin as measured on a coated thin film and by the Evelyn-Malloy and Jendrassik-Gróf methods. We examined serum samples from patients and studied the effects of protein, hemoglobin, and lipids on bilirubin measurement. Results from the thin-film assay compared favorably with those of the other methods. Total and within-day precision (CV), assessed over a one-year period, were better than 6% and 3%, respectively, at all concentrations. Analytical recovery was 99 +/- 3%. Samples from individuals having a wide range of liver diseases demonstrated, by linear regression, good correlation between the thin-film method and the two wet-chemistry methods (correlation coefficients of 0.990 and 0.994). We conclude that the thin-film method offers a valid alternative assay for total bilirubin.

Adult↗
PubMed1984

Estimation of unconjugated, conjugated, and "delta" bilirubin fractions in serum by use of two coated thin films.

We used two coated thin films to measure the concentrations of unconjugated, conjugated, and total bilirubin as well as bilirubin covalently bound to albumin ("delta" bilirubin) in more than 400 serum samples. We measured the unconjugated and conjugated species by determining their reflection densities at two wavelengths (400 and 460 nm) on a coating designed for the enhanced spectral measurement of bilirubin but which does not register the delta form. Total bilirubin was measured by use of a diazo-based thin film (Clin Chem 29: 37-41, 1983). We estimated the concentration of delta bilirubin by subtracting the sum of unconjugated and conjugated bilirubin from the concentration of total bilirubin. All measurements agree well with those by comparative methods, as shown by linear regression. Slopes ranged from 0.92 to 1.02, correlation coefficients from 0.935 and 0.998. Linear combinations of these values can also be used to compute other results; e.g., the sum of conjugated and delta bilirubin can be considered to be an estimate of "direct"-reacting bilirubin.

Autoanalysis↗
PubMed1983

The clinical importance of a protein-bound fraction of serum bilirubin in patients with hyperbilirubinemia.

A directly reacting fraction of bilirubin that is probably covalently bound to albumin (albumin-bound bilirubin) has recently been described. To determine its clinical importance we used a new high-performance liquid-chromatography technique to measure it in the serum of 200 patients with hyperbilirubinemia from various causes. Albumin-bound bilirubin was an important fraction (8 to 90 per cent) of total bilirubin in patients with hepatocellular and cholestatic jaundice as well as in patients with the Dubin-Johnson syndrome. It was not detected in normal volunteers, neonates with physiologic jaundice, or patients with Gilbert's disease or hemolysis. Thus, albumin-bound bilirubin appears in serum when hepatic excretion of conjugated bilirubin is impaired. It becomes a larger component of serum bilirubin as jaundice subsides, delaying resolution of this disorder and causing bilirubin to persist in plasma after it has disappeared from the urine.

Bilirubin↗
PubMed1983

Fractures of the femoral shaft in a regional hospital setting.

We reviewed the efficacy of treatment techniques for femoral shaft fractures in our regional rural hospital setting. One hundred fifty consecutive primary femoral shaft fractures were managed at the Medical Center Hospital of Vermont during the period 1974 through 1979. The method of treatment was determined by the attending orthopedic faculty. Each case was evaluated at the time of initial hospital treatment, at 30 days postinjury, and at 1 year postinjury. Patient profiles, methods of injury, types of fracture, and associated injuries were reviewed. The choice of operative or nonoperative treatment in the first 30 days was the most important factor in the result at 1 year. Results were graded as "good' if angulation was 0-5 degrees in the A-P and/or lateral views; "fair', 6-10 degrees; and "poor', greater than 10 degrees or any need for supplemental surgery to achieve union. Shortening, infection, and thrombophlebitis were infrequent in this series. (formula: see text) Overall rate of supplemental surgery was 37% for the initially nonoperative treated femoral shaft fractures. In this series operative intervention gave surer results with an earlier return to full ambulation and more anatomic repair than nonoperative methods.

Adult↗
PubMed1983

The anterior cervical plate.

The anterior cervical plate was employed routinely in 13 anterior cervical fusions in adults at the Medical Center Hospital of Vermont (MCHV) from October 1979 to December 1980. A method for installation of the implant is presented. Review of these patients shows that the 11 survivors have satisfactory alignment of their cervical spines, with adequately evolving fusions. Technical problems include plate position and screw depth. This demanding method is now reserved for special indications.

Adult↗
PubMed1983

Treatment of tibial shaft fractures by percutaneous Küntscher nailing. Technical difficulties and a review of 50 consecutive cases.

Intramedullary nailing of the tibia is a controversial procedure for fractures of the tibial shaft. Experience with 50 fractures (58% acute, 8% pathologic, and 34% unsuccessfully treated previously by other methods) with an average follow-up period of one year proved that tibial Küntscher nailing is effective. Mean time to clinical union, with patients independently ambulatory and resuming all work activity, was 29 weeks. Union was demonstrated radiographically at 13 weeks. The major complications were delayed union (2 patients), nail protrusion at the knee (2 patients), osteitis (1 patient), and thrombophlebitis (1 patient). Antirotation wires were used in addition to a Küntscher nail for fractures with inherent rotational instability. Blocking screws were used for fractures predisposed to bending. Technical problems arose most often at the nail entrance site, in negotiation of Herzog's curve, and in selection of proper nail length and caliber. With experience and technical skill, even highly complex tibial fractures can be successfully treated by this method.

Adolescent↗