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Biomedical subjects

R L Harris

Publications and source records attributed to R L Harris.

18 recordsLinked to original sources
PubMed1992

Prostatic abscess due to Histoplasma capsulatum in a patient with the acquired immunodeficiency syndrome.

Disseminated histoplasmosis is a systemic fungal infection that may occur in previously healthy or immunocompromised patients. The condition is being recognized with increasing frequency in persons infected with the human immunodeficiency virus. The most common organs involved include the lung, bone marrow, lymph nodes, liver, adrenals and central nervous system, with genitourinary involvement being exceedingly unusual. We describe a Histoplasma capsulatum prostatic abscess occurring after therapy for pulmonary histoplasmosis in a patient with the acquired immunodeficiency syndrome. The prostate may be a difficult focus from which to eradicate disseminated fungal infection in immunocompromised patients.

Abscess↗
PubMed1992

Extraparenchymal neurocysticercosis: report of five cases and review of management.

Neurocysticercosis due to parenchymal cysts carries a good prognosis regardless of therapy. Extraparenchymal neurocysticercosis (including ventricular, spinal, and subarachnoid types) carries a poorer prognosis. Most extraparenchymal cases present with hydrocephalus. Medical treatment alone in doses and schedules developed for parenchymal disease is frequently unsuccessful. For ventricular disease, most cases can be managed with shunting procedures either alone or together with the administration of antiparasitic agents (e.g., praziquantel or albendazole), without extirpation of the cysts. Subarachnoid disease was formerly associated with a case fatality rate of about 50%. However, with the combination of shunting procedures for hydrocephalus, antiparasitic agents, and, in some cases, surgical extirpation of the cysts, the prognosis is much improved. Spinal cysticercosis can be either leptomeningeal (which responds like subarachnoid disease) or intramedullary. For all forms of neurocysticercosis, the role of antiparasitic agents needs to be better defined.

Adult↗
PubMed1992

Successful medical management of a patient with multiple hepatic abscesses due to Edwardsiella tarda.

Isolation of Edwardsiella tarda in humans has been associated with an asymptomatic carrier state as well as mild, self-limited diarrheal illness. Extraintestinal manifestations have included soft-tissue infections, meningitis, osteomyelitis, cholangitis, and sepsis. Only three cases of patients who had documented hepatic abscess due to E. tarda have been reported in the English-language literature; two patients died, and the third required a laparotomy and drainage. We report what is, to our knowledge, the first autochthonous case of hepatic abscess due to E. tarda in the United States and the first case that was successfully managed with antibiotic therapy alone.

Adult↗
PubMed1991

Cefamandole levels during thoracoabdominal aortic aneurysm surgery.

The pharmacokinetics of prophylactic antibodies may differ in cardiac and aortic aneurysm surgery for at least two reasons: aortic aneurysm surgery generally entails a greater blood volume loss and replacement, and aortic aneurysm surgery usually does not require extracorporeal cardiopulmonary bypass. We prospectively studied two different cefamandole dosing regimens in patients undergoing aortic aneurysm surgery (phase 1, 1 gm intravenously at the induction of anesthesia; phase 2, 2 gm intravenously at the induction of anesthesia followed by 1 gm intravenously every 2 hours during surgery). In phase 1 and 2 plasma levels were measured at the time of skin incision, aortic cross-clamping, aortic unclamping, and skin closure. In phase 2 cefamandole elimination in urine and cell-saver effluent was also determined. An adequate plasma level of 10 micrograms/ml was maintained in only 4 of 14 patients in phase 1, but in 10 of 10 patients in phase 2. Cefamandole loss in cell-saver effluent was 136 +/- 100 mg, which was 13% of the measured renally excreted amount. As has been previously shown in cardiac surgery, a cefamandole prophylactic antibiotic regimen of 2 gm intravenously at the induction of anesthesia followed by 1 gm every 2 hours during surgery provides a dependable and practical dosing regimen in patients undergoing aortic aneurysm surgery.

Aged↗
PubMed1978

Multiple antibiotic allergies.

A case of an 18-year-old woman with postoperative infectious complications and multiple antibiotic allergies is discussed. The case poses several problems: the selection of an appropriate antibiotic to combat the infection, the persistence of the infection, and the treatment of multiple allergic responses to each of the antibiotic agents chosen.

Adolescent↗
PubMed1976

Inhibition of wool follicle DNA synthesis by mimosine and related 4(1H)-pyridones.

The in vitro incorporation of [3H]thymidine has been examined in thin slices of sheep skin. Most of the radioactivity (88%) was incorporated into the bulb cells of the wool follicles, and the technique is therefore suitable for the study of some aspects of wool follicle DNA synthesis. The effect of mimosine and a number of related 4(1H)-pyridones on [3H]thymidine incorporation into sheep skin slices was examined. Mimosine was shown to inhibit the incorporation at a concentration of 0-2 mM. At this concentration, the incorporation of [3H]uridine or [14C]leucine was not affected. The inhibition of [3H]thymidine incorporation was time dependent, 2 h of incubation being required for maximal inhibition of DNA synthesis, and was readily reversible by removal of mimosine from the incubation medium. The 3-hydroxyl-4-oxo function of the pyridone ring appears to be directly involved in DNA synthesis inhibition. The amino acid side chain is not a toxophoric centre, but changes in its polarity have been shown to affect the inhibitory activity. The results suggest that the primary action of mimosine on the inhibition of wool biosynthesis in vivo is the inhibition of follicle bulb cell DNA synthesis and consequently of cell division.

Animals↗
PubMed1976

A model for deposition of fibers in the human respiratory system.

A mathematical model for estimating lung deposition of fibers is described. It is based on the aerodynamic behavior of thin straight rods. Predicted deposition values for rods of various equivalent aerodynamic diameters and lengths, for each of three tidal volumes and for each of three respiratory system compartments are reported.

Bronchi↗
PubMed1975

Investigation of the transport of metals and orthophosphate away from a sewage treatment plant outfall.

The distribution of O2, chlorophyll a, alkalinity, phosphate, Ca, Mg, Mn, Fe, Cu, Zn, Cd and Pb has been measured in the discharge plume of the large sewage treatment plant on Back River, Maryland. The concentrations of phosphate and the trace metals decrease downstream more rapidly than can be accounted for by conservative dilution. Solubility calculations suggest that saturation with respect to phosphate or oxyhydroxide phases could limit the mobility of phosphate, Fe, Mn, and Pb. For Cu, Zn, and Cd, saturation is not a feasible control mechanism, and other processes such as biofixation or adsorption are probably involved.

Alkalies↗
PubMed1975

Visual acuity improvement in eyes with corneal scars fitted with contact lenses.

The vision of 190 eyes of 130 patients with corneal scars was tested with contact lenses, of which 166 eyes subsequently were fitted with contact lenses. Over 75% of all eyes with corneal scars showed a visual acuity improvement to 6/12 or better. All eyes with a nebular or macular corneal scar and an initial visual acuity of 6/60 or better improved to 6/12 or better. The visual acuity of 77% of the eyes fitted with contact lenses, compared to the visual acuity of 36% of the same eyes obtained with spectacle lenses, improved to 6/12 or better.

Adolescent↗
PubMed1975

The influence of fibre shape in lung deposition-mathematical estimates.

Inhaled fibres deposit by sedimentation, diffusion, impaction, and interception in airways of the respiratory system. Long straight fibres may exhibit periodic motiion with ordered orientation in those airways having laminar flow. We assume that irregular fibres are randomly oriented in airways. Mathematical models based on respiratory system architecture, respiratory airflow, and mathematical expressions for deposition mechanisms have been developed to predict deposition in respiratory compartments of fibres in ordered orientation and of various fibre confirgurations in random orientations. The size and shape characteristics of chamber aerosols generated with U.I.C.C. asbestos specimens have been determined. Combinations of the chamber aerosol data with mathematical estimates of deposition suggest that fibre shape as well as size influences the magnitude of deposition in pulmonary spaces. For size distributions such as those of the U.I.C.C. asbestos chamber aerosols, the mathematical models predict pulmonary spaces deposition for straight fibres in ordered orientation about twice as great as for irregular fibres in random orientation.

Aerosols↗