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Biomedical subjects

J L Harden

Publications and source records attributed to J L Harden.

4 recordsLinked to original sources
PubMed2001

Thalidomide is distributed into human semen after oral dosing.

As part of a double-blind placebo-controlled study of the effect of thalidomide on body weight and the viral load of human immunodeficiency virus-seropositive patients, plasma and semen samples were analyzed for the presence of thalidomide. Patients were orally dosed with 100 mg of thalidomide/day for 8 weeks. Blood samples were obtained at baseline and weeks 4, 8, and 12, and semen was obtained at baseline and weeks 4 and 8. Samples were extracted with solid-phase cartridges and analyzed by liquid chromatography/tandem mass spectrometry using atmospheric pressure chemical ionization in the negative ion mode. Two of four patients taking thalidomide were able to provide semen samples. Both had detectable levels of thalidomide in their plasma (10-350 ng/ml) and semen (10-250 ng/g) at weeks 4 and 8. There was an apparent correlation between plasma and semen levels. Semen levels could be significantly greater for therapeutic doses of more than 100 mg/day. Since the threshold dose for birth defects and thalidomide exposure is not known, male patients are advised to use barrier contraception.

Administration, Oral↗
PubMed1998

Reversible hydrogels from self-assembling artificial proteins.

Recombinant DNA methods were used to create artificial proteins that undergo reversible gelation in response to changes in pH or temperature. The proteins consist of terminal leucine zipper domains flanking a central, flexible, water-soluble polyelectrolyte segment. Formation of coiled-coil aggregates of the terminal domains in near-neutral aqueous solutions triggers formation of a three-dimensional polymer network, with the polyelectrolyte segment retaining solvent and preventing precipitation of the chain. Dissociation of the coiled-coil aggregates through elevation of pH or temperature causes dissolution of the gel and a return to the viscous behavior that is characteristic of polymer solutions. The mild conditions under which gel formation can be controlled (near-neutral pH and near-ambient temperature) suggest that these materials have potential in bioengineering applications requiring encapsulation or controlled release of molecular and cellular species.

Amino Acid Sequence↗
PubMed1995

Femoral catheters increase risk of infection in total parenteral nutrition patients.

Central venous access for the administration of total parenteral nutrition is usually achieved via the subclavian or internal jugular veins. Although a high incidence of complications has been reported with the use of femoral catheters for central venous access, this route has been used when traditional central venous access is contraindicated. We retrospectively reviewed 171 patients who received total parenteral nutrition via a central venous triple-lumen catheter and compared the rates of infections in femoral vs nonfemoral access. A literature review was performed to identify associated complications of and appropriate indications for femoral catheter use. In the 171 patients studied, 355 triple-lumen catheters were placed; these included 331 nonfemoral catheters and 24 femoral catheters. Femoral catheters were placed in nine patients. Femoral catheters had a greater incidence of positive tips (42% vs 6.9%, p < .001) and related bacteremia (16.7% vs 1.8%, p = .002) than did nonfemoral catheters. The organisms most commonly isolated from the blood and catheter tips of both catheter access sites were methicillin-resistant Staphylococcus epidermidis and Candida. The use of femoral catheters for central venous access for total parenteral nutrition administration results in an increased risk of infectious complications.

Adult↗