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Biomedical subjects

R L Hopfer

Publications and source records attributed to R L Hopfer.

At least 55 records · Page 3Linked to original sources
PubMed1984

Prophylaxis of Candida albicans infection in neutropenic mice with liposome-encapsulated amphotericin B.

The efficacy of liposome-encapsulated amphotericin B in the prophylaxis of disseminated Candida albicans infections in neutropenic mice was studied. The administration of liposome-encapsulated amphotericin B was associated with protection against infection with C. albicans when used at doses of greater than or equal to 2 mg of amphotericin B per kg of body weight. Neither empty liposomes nor free amphotericin B showed prophylactic efficacy.

Agranulocytosis↗
PubMed1984

In vitro antifungal activities of amphotericin B and liposome-encapsulated amphotericin B.

The in vitro activities of liposome-encapsulated amphotericin B and free amphotericin B against Candida albicans 336 were comparable. Amphotericin B concentrations 12-fold and greater than 50-fold higher were required to kill the same organism when cholesterol and ergosterol were incorporated into the liposomes. The addition of cholesterol to liposomes caused a significant increase in the minimal fungicidal concentration of amphotericin B in 7 of 19 other yeast strains tested, whereas ergosterol caused an increase in 18 of the 19 strains.

Amphotericin B↗
PubMed1984

Diarrhea due to Plesiomonas shigelloides in cancer patients.

Plesiomonas shigelloides was isolated from the stools of two patients with gastrointestinal malignancies and from one "healthy" patient with diarrhea. No other enteric pathogens were isolated. One patient was neutropenic after antineoplastic chemotherapy. The two cancer patients had crampy abdominal pain and severe diarrhea and required antibiotic therapy for resolution of symptoms. The third patient responded to symptomatic treatment. Patients with gastrointestinal malignancies may be more susceptible to gastroenteritis caused by P. shigelloides than normal individuals, and these infections may be more severe than those seen in normal individuals.

Adult↗
PubMed1984

Bacteremia caused by Campylobacter-like organisms in two male homosexuals.

Bacteremia caused by newly described Campylobacter-like organisms occurred in two immunosuppressed homosexual patients with tuberculosis. Although these organisms grow well in aerobic bottles using a radiometric blood culture system, they are not readily seen in gram-stained smears and are easily missed if routine subculture methods are used. Microscopic examination of wet preparations and subculture to brucella agar base supplemented with 10% sheep blood and incubated in microaerophilic conditions are useful for identification and isolation. The recovery of Campylobacter-like organisms from the blood suggests that these organisms, formerly known only to be associated with proctocolitis or asymptomatic rectal infection in homosexual men, can also cause systemic infection in these patients.

Adult↗
PubMed1983

Human cryptosporidiosis: spectrum of disease. Report of six cases and review of the literature.

Although once regarded exclusively as an animal parasite, Cryptosporidium has emerged during the last decade as a cause of diarrhea in humans. Of the 43 cases of human cryptosporidiosis reported, 27 patients in whom either humoral or cell-mediated immune defects were present had chronic protracted diarrhea that was almost invariably unresponsive to therapy and culminated in death. In contrast, 16 patients with intact immune systems had either self-limited disease or were asymptomatic. Animal exposure was almost exclusively recorded in the latter group. During the last six months at University of Texas M. D. Anderson Hospital and Tumor Institute, Houston, gastrointestinal (GI) tract cryptosporidiosis developed in six homosexual men with acquired immune deficiency syndrome (AIDS). The diagnosis of cryptosporidiosis was established histologically in five patients. In four, cryptosporidial oocysts were detected in the stool. In addition to extensive GI tract cryptosporidiosis, two patients had biliary tract involvement. Multiple chemotherapeutic agents failed to control the disease, and five patients eventually died. Cryptosporidiosis should be considered in the differential diagnosis of diarrhea, in animal handlers or in the severely compromised patient, especially one with AIDS, who has chronic protracted diarrhea.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Treatment and prophylaxis of disseminated infection due to Candida albicans in mice with liposome-encapsulated amphotericin B.

The toxicology of liposome-encapsulated amphotericin B in mice and its efficacy in the treatment and prophylaxis of systemic candidiasis in these animals were studied. The toxicology studies indicated that the maximal tolerated dose of free amphotericin B was 0.8 mg/kg of body weight and the 50% lethal dose (LD50) was reached at 1.2 mg/kg, while neither the maximal tolerated dose nor the LD50 for the liposomal amphotericin B was reached at a dose of 12 mg/kg. No abnormalities in blood chemistry or histology were observed in the animals injected with encapsulated amphotericin B, while the administration of free amphotericin B was associated with nephrocalcinosis and renal parenchymal edema. The encapsulated drug was as effective as the free drug when used in similar concentrations, while the animals treated with higher concentrations of liposomal amphotericin B (4 mg/kg) had a longer survival time. Thus, an improved therapeutic index resulted by encapsulating amphotericin B in liposomes.

Amphotericin B↗
PubMed1983

Routine use of BACTEC 16B bottles to remove antibacterial and antitumor agents from blood cultures of cancer patients.

A total of 1,764 paired sets of BACTEC 6B and 16B blood culture bottles were collected from patients for analysis. The majority of the patients were receiving antibiotic therapy at the time the blood specimens were collected. A total of 126 isolates were considered clinically significant. Of these, 58 grew in both 6B and 16B bottles, 25 grew only in 6B bottles, and 43 grew only in 16B bottles. In both bottles, the same amount of time was required to detect a positive culture. In 18 patients, septicemias were detected in the 16B bottles that were not detected in the 6B bottles. In seven patients, microorganisms were detected in the 6B bottles that were not detected in the 16B bottles. Interestingly, the antibiotic therapy was changed for only 4 of the 18 patients whose septicemias were detected only in the 16B bottles. Finally, an in vitro study showed that certain chemotherapeutic agents can cause the inhibition of growth of several microorganisms when tested in 6B bottles. These inhibitory effects were reduced or eliminated when the same organism-drug combinations were tested in 16B bottles.

Antineoplastic Agents↗
PubMed1982

Pseudooutbreak of cryptococcal meningitis.

A pseudooutbreak of cryptococcal meningitis was caused by the use of contaminated albumin solution used in the preparation of Papanicolaou-stained slides of cerebrospinal fluid. Organisms were seen in cytocentrifuge preparations, but not in India ink preparations of cerebrospinal fluid specimens. Cryptococcal antigen tests were positive and Cryptococcus neoformans was cultured from the albumin-treated cerebrospinal fluid specimens and from the albumin solution.

Cerebrospinal Fluid↗
PubMed1982

Diagnostic value of the enzyme-linked immunosorbent assay for detection of Candida albicans cytoplasmic antigen in sera of cancer patients.

To diagnose systemic candidiasis we developed an enzyme-linked immunosorbent assay (ELISA) for the quantitation of Candida albicans cytoplasmic antigen in sera of cancer patients. The antigen concentration was evaluated in 59 patients divided into several groups according to clinical, histological, and microbiological findings as well as antimicrobial treatment. All of seven patients with proven disseminated candidiasis had elevated antigen concentrations (mean = 1,200 ng/ml). Among 13 patients with suspected disseminated candidiasis, 9 had elevated antigen concentrations (mean = 1,039 ng/ml). The remaining four patients showed negative antigen (less than 125 ng/ml). In a group of patients with fever of unknown origin, 5 of 17 had high antigen concentrations (mean = 1,220 ng/ml) and the rest were negative. Patients with bacterial infection (6 patients), aspergillosis (3), cryptococcosis (4), coccidioidomycosis (3), and no infection (6), as well as normal healthy adults (31), had antigen concentrations of less than 100 ng/ml. This ELISA is rapid, sensitive, and specific and is a helpful diagnostic tool in the evaluation of candidiasis in cancer patients.

Adolescent↗
PubMed1982

Pneumonia caused by a previously undescribed bacterium.

A new and as yet unidentified bacterium was isolated from the lung tissue of a cancer patient with bilateral pneumonia. Clinically, the pneumonia was consistent with legionellosis; the organism cultured from the lung grew only on the charcoal-yeast extract agar routinely used for Legionella isolation. Subsequent testing, however, showed the organism to be quite distinct from the known Legionella species in its biochemical, antigenic, and growth characteristics.

Bacteria↗
PubMed1981

Valuable of terminal subcultures from negative BACTEC blood culture bottles.

Terminal subcultures from 5,354 negative BACTEC blood culture bottles did not significantly improve the detection of positive cultures. Only 15 of the 545 total isolates were recovered from the terminal subcultures. All 15 of these isolates were either considered contaminants or had been previously detected.

Bacteria↗