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Biomedical subjects

R L Hopfer

Publications and source records attributed to R L Hopfer.

At least 73 records · Page 4Linked to original sources
PubMed1980

Systemic mycosis due to Trichosporon cutaneum: a report of two additional cases.

Two additional cases of systemic mycosis due to Trichosporon cutaneum are reported and are compared with the previously published case of Rivera and Cangir. Both patients (a four-year-old male and a 57-year-old female) had acute leukemia for which they were receiving chemotherapy, and both presented with fever that was unresponsive to conventional antibiotics. Both had positive blood cultures for Trichosporon cutaneum. The disease was further documented in the four-year-old male by renal biopsy and by bone marrow culture; he was treated with apparent success with amphotericin B. However, the 57-year-old female died shortly after the begining of similar treatment, and autopsy demonstrated involvement of the left kidney, spleen, bone marrow, and liver. The organism in both these cases, as well as the case of Rivera and Cangir, exhibited both hyphal and yeastlike forms in tissue sections. We believe that the therapeutic success in the case of the four-year-old male was primarily related to his remission from leukemia.

Amphotericin B↗
PubMed1980

Autobac I procedure to assess susceptibility to Cefaclor.

Agar dilution and Autobac I tests were performed to compare the susceptibility of 1,000 bacterial isolates to cefaclor and cephalothin. The standard Autobac methodology will correctly predict resistance to cefaclor. The test methodology seems to influence in vitro results, since more strains of gram-negative bacteria were susceptible to cefaclor by the Autobac I method than by the agar dilution test.

Cefaclor↗
PubMed1980

Radiometric detection of yeasts in blood cultures of cancer patients.

During a 12-month period, 19,457 blood cultures were collected. Yeasts were isolated from 193 cultures derived from 76 cancer patients. Candida albicans or Candida tropicalis accounted for 79% of isolates. Of the three methods compared, the radiometric method required 2.9 days to become positive, "blind" subculture required 2.6 days, and Gram stains required 1 day. However, the radiometric method was clearly superior in detecting positive cultures, since 73% of all cultures were first detected radiometrically, 22% were detected by subculture, and only 5% were detected by Gram stain. Although 93% of the isolates were detected by aerobic culture, five (7%) isolates were obtained only from anaerobic cultures. Seven days of incubation appear to be sufficient for the radiometric detection of yeasts.

Aerobiosis↗
PubMed1979

Detection by counterimmunoelectrophoresis of anti-Candida precipitins in sera from cancer patients.

Five antigen preparations from yeast-phase cells and hyphalphase cells of Candida albicans were used to detect antibodies in sera from cancer patients by use of counterimmunoelectrophoresis (CIE). Sera from uninfected patients, patients with superficial infections, and patients who had invasive or systemic candidiasis were analyzed for antibodies. A high incidence (27%) of false-negative data was obtained for patients who had systemic candidiasis. Serum titers of all patient groups were below 1:10. Of the antigens tested, cytoplasmic antigen from yeast-phase cells provided the greatest sensitivity and diagnostic value.

Antigens, Fungal↗
PubMed1979

Improved blood culture medium for radiometric detection of yeasts.

The influence of medium composition on the rate of CO2 production by yeasts in simulated blood cultures was determined in the Bactec radiometric system. A yeast nitrogen base broth containing [14C]glucose and Triton X-100 allowed the detection of positive cultures earlier than the regular Bactec blood culture media.

Blood↗
PubMed1979

Blood cultures with the BACTEC 225 radiometric microbial growth detection system.

The BACTEC 225 automated radiometric blood culture system was compared with a conventional blood culture bottle method for its ability to improve the rapid laboratory diagnosis of bacteremia in cancer patients. The BACTEC 225, in combination with routine blind subcultures and smears of radiometrically negative culture vials, detected two thirds, of all positive cultures within 24 h and shortered the detection time generally by 24-48 h. With the recommended growth index setting of 30, radiometrically false-positive findings are rare and are usually due to leukocytosis resulting from infection or leukemia.

Bacteriological Techniques↗
PubMed1978

Candida tropicalis arthritis - assessment of amphotericin B therapy.

A 28 year old male heroin addict developed Candida tropicalis infection of the knee joint in association with candidemia. Assessment of amphotericin B therapy was facilitated by the determination of serum and synovial fluid amphotericin B concentrations using a radiometric bio-assay method. The results indicate that adequate synovial fluid drug levels were achieved with intravenous systemic therapy.

Adult↗
PubMed1977

Amphotericin B susceptibility testing of yeasts with a bactec radiometric system.

The effect of amphotericin B on CO(2) production was studied using a Bactec 225. A radiometric procedure for yeast susceptibility testing that requires 3 h of incubation was developed. A total of 48 yeast isolates was tested in this system and the results were correlated to tube dilution studies. The drug concentration causing at least a 44% decrease in CO(2) production correlated to the tube dilution minimal inhibitory concentration in 85% of isolates tested and was within one tube dilution of the minimal inhibitory concentration in over 95% of yeasts tested.

Amphotericin B↗
PubMed1977

Radiometric determination of the concentration of amphotericin B in body fluids.

A new assay was developed to determine the concentration of amphotericin B in body fluids. The Bactec radiometric system was used to measure CO(2) production by a test strain, Candida albicans MDA 448, in the presence of amphotericin B. After 5-h incubation, drug concentrations as low as 0.2 mug/ml could be detected. The results are comparable to those of the commonly used agar diffusion assay with Paecilomyces varioti.

Amphotericin B↗
PubMed1976

Caffeic acid-containing medium for identification of Cryptococcus neoformans.

A new growth medium containing caffeic acid and ferric citrate is described. The pigment produced on this medium is specific for the identification of Cryptococcus neoformans and differentiates it from other cryptococci. The medium is more easily compounded and requires less time for pigment formation than the conventional Guizotia extract media. The medium is stable in the dry form as well as in the prepared form.

Caffeic Acids↗
PubMed1976

Six-hour pigmentation test for the identification of Cryptococcus neoformans.

Cryptococcus neoformans colonies can be identified within 6 h using paper disks containing caffeic acid and ferric citrate. Indentification is based on the development of a dark brown pigment. Saprophytic Cryptococcus species and common clinically isolated yeasts do not develop the brown color. The concentration of the reagents and the method of storage of the impregnated paper disks are critical for the rapid and specific development of the pigment.

Caffeic Acids↗
PubMed1975

Antibodies with affinity for epithelial tissue in chronic dermatophytosis.

Antibodies to dermatophytes which also had affinity for intercellular material of epithelial tissue, were detected in sera from 80% of patients with chronic dermatophytosis using an indirect fluorescent antibody test. The class of immunoglobulins reactive with both the dermatophyte and the epithelial tissue was identified as IgM. IgM antibodies with affinity for arthrospores of Trichophyton mentagrophytes and intercellular substance of epithelial tissue could be removed from sera with mycelium of Trichophyton rubrum.

Adult↗
PubMedDate not supplied

Purification of an antigenic vaccine protein by selective displacement chromatography.

A recent advance in the state of the art of displacement chromatography has been the development of selective displacement chromatography. In this process, the bioproduct of interest is selectively displaced while impurities with lower retention are eluted in the induced salt gradient and higher retained impurities are desorbed after the breakthrough of the displacer front. In this manuscript, selective displacement chromatography is employed to purify an antigenic vaccine protein (AVP) from an industrial process stream. Displacers were screened and an operating regime plot was employed to establish appropriate conditions for selective displacement. The selective displacement process was successful and resulted in AVP that was equivalent in purity to product obtained at commercial production scale after conventional step gradient chromatography. Methods used to characterize the purified protein include size-exclusion chromatography, SDS-PAGE, isoelectric focusing, N-terminal amino acid sequence analysis, and amino acid composition analysis. This is the first report of the purification of a commercially and pharmaceutically significant protein using selective displacement chromatography and thereby sets the stage for the implementation of selective displacement chromatography for the downstream processing of biologicals.

Amino Acid Sequence↗
PubMedDate not supplied

Septic arthritis due to Candida species on patients with cancer: report of five cases and review of the literature.

In disseminated candidiasis, various organs frequently become involved, usually as a consequence of hematogenous spread of the organism. However, involvement of the joints is rare even with dissemination. Nineteen cases of joint involvement have previously been reported in adults and 21 cases in children. The most commonly involved joint has been the knee; in such cases, amphotericin B has been effective in controlling the infection. Five patients with cancer developed septic arthritis due to Candida species at the M. C. Anderson Hospital and Tumor Institute in the past five years. Four of these patients were seen in 1980. Candida albicans was isolated from three patients and Candida tropicalis from two. All five patients had predisposing conditions - e.g., intravenous and/or urinary catheterization, neutropenia, and previous treatment with steroids and antibiotics. The knee was the affected joint in all five. Different modalities of treatment were used, including intravenous miconazole, oral ketoconazole, and systemic and local amphotericin B; adequate levels of these drugs were found in the joint fluid when measured. Infection was cured in two patients. The condition of the third patient improved. The fourth patient died of disseminated disease despite therapy, and the fifth died of malignancy without the benefit of antifungal therapy. For treatment of such infections, the use of an antifungal agent is recommended in addition to frequent evacuation of the joint fluid. Some new compounds may prove useful alternatives to amphotericin B. Arthritis can be resolved even in the presence of unresolved disseminated disease.

Adolescent↗
PubMedDate not supplied

Bacteremia caused by Aeromonas species in hospitalized cancer patients.

Bacteremia caused by Aeromonas species occurred in 24 hospitalized patients in a cancer institute during a 13-year period. All but one of these patients had a malignancy (88% had leukemia), and most were receiving chemotherapy for cancer. There was a striking numerical predominance of male patients (82%). Unlike some previously described patients with infections due to this organism, none of these 24 patients had recently been exposed to fresh or salt water or to fish. The source of the infecting organism was thought to be endogenous--i.e., from patients' own gastrointestinal tracts. The clinical presentation of sepsis caused by this organism was nonspecific, except that ecthyma gangrenosum occurred in several patients. The overall mortality rate was 28%. The combination of an aminoglycoside and a cephalosporin is appropriate therapy for bacteremia caused by Aeromonas species.

Acute Disease↗
PubMedDate not supplied

Infections caused by Drechslera species: case report and review of the literature.

Organisms belonging to Drechslera species are rare causes of human infection and are considered opportunistic pathogens. Only 10 cases of human infection with these organisms have been reported in the literature; an additional case--that of a healthy young woman with chronic pansinusitis due to Drechslera spicifera causing nasal obstruction and erosion of bone--is described herein. This case was managed successfully by means of surgical debridement and therapy with amphotericin B and ketoconazole. A review of the literature suggests that infections caused by Drechslera species can in fact occur in a healthy host. Involvement of the paranasal sinuses and the central nervous system is common and potentially life-threatening. Appropriate therapy consists of the administration of amphotericin B, either alone or in combination with other antifungal agents, and surgical debridement when indicated.

Adolescent↗