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Biomedical subjects

A P Lopez

Publications and source records attributed to A P Lopez.

6 recordsLinked to original sources
PubMed2000

A pilot study of noninvasive methods to assess healed acute and chronic wounds.

BACKGROUND: A variety of instruments are available that can objectively assess physical parameters of the skin such as strength, firmness, elasticity, hydration, and color, often undetected by clinical assessment. OBJECTIVE: To assess the physical properties of healed acute and chronic wounds using several noninvasive instruments. METHODS: Four patients with healed acute wounds and four patients with healed chronic wounds were studied using ballistometric, impedance, levarometric, and spectrophotometric measurements. RESULTS: In general, scars were harder, less elastic, dryer, and more erythematous than control skin. These differences were more pronounced in healed chronic wounds. CONCLUSION: A scar from an acute surgical wound becomes softer, more elastic, dryer, less erythematous, and less pigmented as it ages. In contrast, chronic wound scars become harder as they age. These different properties of healed acute wounds and healed chronic wounds may be a result of the different healing processes in each wound type.

Acute Disease↗
PubMed1989

Tissue concentrations and bioactivity of amphotericin B in cancer patients treated with amphotericin B-deoxycholate.

We have studied amphotericin B concentrations in tissues of 13 cancer patients who died after having received 75 to 1,110 mg (total dose) of amphotericin B-deoxycholate for suspected or proven disseminated fungal infection. Amphotericin B concentrations were measured by high-pressure liquid chromatography (HPLC) and by bioassay, the latter being done on tissue homogenates as well as on tissue methanolic extracts. The fungistatic and fungicidal titers of the tissue homogenates were also tested against three strains of Candida albicans and one strain of Aspergillus fumigatus. Tissue concentrations of amphotericin B measured by HPLC varied with the tested tissues as well as with the total dose of amphotericin B-deoxycholate administered and ranged from 0.4 to 147.1 micrograms/g. A mean of 38.3% (range, 23.0 to 51.3%) of the total dose was recovered by HPLC from all of the tested organs. Bioassay of tissue methanolic extracts reached 58 to 81% of the concentration measured by HPLC, whereas only 15 to 41% was recovered from the homogenates. Overall, 27.5% of the total dose was recovered from the liver, 5.2% was recovered from the spleen, 3.2% was recovered from the lungs, and 1.5% was recovered from the kidneys. The median concentration in bile was 7.3 micrograms/ml, suggesting that biliary excretion could contribute to amphotericin B elimination to an estimated range of 0.8 to 14.6% of the daily dose. Fungicidal titers were seldom measured in tissues, but fungistatic titers were observed and were linearly correlated with amphotericin B concentration measured by HPLC. In conclusion, only a small proportion of the amphotericin B administered as amphotericin B-deoxycholate to patients seems diffusible and bioactive.

Adult↗
PubMed1988

Diarrhea in AIDS.

The spectrum of illness associated with AIDS has been enlarging since its initial description in 1981, and the gastrointaestinal tract continues to be one of the major targets of this devastating disease. The many causative agents are discussed in this article, including bacteria, viruses, fungi, protozoa, helminths, and various noninfectious diseases.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Bactericidal activity and killing rate of serum from volunteers receiving pefloxacin alone or in combination with amikacin.

Serum bactericidal activities (SBAs) were studied after intravenous administration of pefloxacin (8 mg/kg) and amikacin (7.5 mg/kg) alone or in combination to 15 human volunteers. About 10 strains each of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus were tested. The serum levels of pefloxacin were measured microbiologically by using E. coli KP 1976-712 as the test organism at 0, 30, 60, 120, and 720 min after infusion; at 0, 30, 60, and 720 min these levels were 7 +/- 1.4, 5 +/- 0.8, 4.5 +/- 0.7, and 2.1 +/- 0.6 mg/liter (mean +/- standard deviation), respectively, with a terminal half-life of 10 h. The serum levels of pefloxacin in the presence of amikacin were measured similarly; 1% sodium polyanethol sulfonate was added to the agar to inactivate amikacin. Treatment with pefloxacin alone resulted in high SBAs against E. coli, K. pneumoniae strains susceptible to cephalothin, and Staphylococcus aureus at the peak concentration; 81 to 100% of the sera had SBAs of greater than or equal to 1:8. However, treatment with pefloxacin alone resulted in low SBAs against K. pneumoniae strains resistant to cephalothin and P. aeruginosa; only 34% of the sera had SBAs of greater than or equal to 1:8. At trough concentrations the percentages of sera with SBAs greater than or equal to 1:8 were 75 to 83% (E. coli), 9 to 27% (K. pneumoniae), 0% (P. aeruginosa), and 10% (S. aureus). The combination of pefloxacin plus amikacin was most often additive; the peak activity was due to amikacin, and the trough activity was due to pefloxacin. Occasionally antagonism occurred with P. aeruginosa, K. pneumoniae, and S. aureus strains. These observations were confirmed by the killing curves in pooled serum obtained at peak and trough levels. Regrowth was observed for seven strains of P. aeruginosa treated with pefloxacin alone; amikacin seemed to prevent this phenomenon.

Amikacin↗
PubMedDate not supplied

CHILD syndrome with linear eruptions, hypopigmented bands, and verruciform xanthoma.

A Colombian girl was born with linear verrucous lesions of the right forearm and fingers, hypopigmented bands and streaks on the right arm, verrucous plaques on the right labium majus which extended to the right upper inner thigh, a crooked right tibia, nasal septum deviation to the right, lumbar kyphoscoliosis to the right, and other right-sided abnormalities. Radiographs showed stippled calcification of the tibial epiphysis, hypoplasia of the calcaneus, and astragalus of the right foot and delta phalanges of the right ring finger. Histologic examination demonstrated hyperkeratosis with ortho- and parakeratosis of the acanthotic epidermis. Keratinocytes in the lower epidermis and connective tissue cells, Schwann cells, and capillary endothelial cells of the papillary dermis showed marked vacuolization, a picture compatible with verruciform xanthoma. Electron microscopy revealed lipid vacuoles with lamellar contents and occasional crystals, compatible with cholesterol, in the dermal cells. Other abnormalities included a large number of vesicles and vacuoles in the upper epidermal keratinocytes and a lack of typical cementsomes; the vesicles and vacuoles were thought to represent abnormal cementsomes (lamellar granules).

Abnormalities, Multiple↗