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Biomedical subjects

J R Perfect

Publications and source records attributed to J R Perfect.

At least 127 records · Page 7Linked to original sources
PubMed1987

Penetration of new azole compounds into the eye and efficacy in experimental Candida endophthalmitis.

We studied the penetration of three azole compounds, ketoconazole, itraconazole, and fluconazole, into the ocular tissues and fluids of rabbits in the presence and absence of ocular inflammation. Drug concentrations were compared with those found in serum and cerebrospinal fluid. The rank order of penetration into eye tissue was fluconazole greater than ketoconazole greater than itraconazole. Fluconazole penetrated freely into both inflamed and uninflamed eyes. The presence of inflammation improved penetration of all three compounds into ocular fluids and tissues. Penetration of these azoles into the anterior chamber of uninflamed eyes and into the cerebrospinal fluid was similar. All three azole compounds reduced the number of yeasts found in the eye in hematogenous Candida albicans endophthalmitis in rabbits when therapy was initiated within 24 h of inoculation. However, only ketoconazole significantly reduced yeast counts in the eye when therapy was postponed for 7 days.

Animals↗
PubMed1987

Efficacy of immune therapy in early experimental Naegleria fowleri meningitis.

Naegleria fowleri meningoencephalitis is usually fatal in humans despite treatment. As a new approach, we tested intracisternal passive immune therapy in rabbits with amebic meningoencephalitis by using antinaegleria immune serum, an immunoglobulin G fraction, and a newly developed monoclonal antibody to N. fowleri. Both the immune serum and an immunoglobulin G fraction isolated from it by affinity chromatography provided a consistent, although temporary, protective effect, shown by prolongation of survival (P = 0.001). Multiple doses of immune serum further prolonged survival (P = 0.005). The protective effect of serum was retained after heating to 56 degrees C. We then developed a monoclonal antibody to N. fowleri which provided similar protection. Passive intracisternal antibody therapy might serve as an adjunctive component in the treatment of amebic meningoencephalitis.

Amebiasis↗
PubMed1987

Retrospective review of amphotericin B use in a tertiary-care medical center.

A retrospective review of amphotericin B use in a tertiary-care medical center was conducted, and use patterns were evaluated. The pharmacy department audited the medical records of all patients who received amphotericin B during 1983. Of 179 patients who received amphotericin B, the medical records of 140 patients were suitable for review. Amphotericin B use increased almost tenfold over a six-year period. Medical services used approximately two thirds of the total drug, while surgery used one fourth. Amphotericin B was used systemically in 98 patients and as a bladder irrigant in 42 patients. In a third of cases, the drug was used when a fungal infection was not documented. Daily dosages of less than 25 mg and total dosages of 500 mg were commonly administered. Amphotericin B was frequently administered with other antimicrobial agents in patients with serious underlying diseases; therefore, evaluation of its efficacy in all patients was difficult. Clinical nephrotoxicity was detected during treatment in approximately 15% of patients. Amphotericin B is no longer used exclusively for classical deep-seated mycoses; frequently, the drug is used as empiric treatment for candida and aspergillus infections. Amphotericin B use has risen because of the difficulty in diagnosing deep-seated mycoses and because of the frequent isolation of yeasts from seriously ill patients. Prospective studies are needed to guide clinicians in determining indications for amphotericin B use and the proper dosage and length of treatment for the drug.

Amphotericin B↗
PubMed1986

Macrophage-mediated fungistasis: requirement for a macromolecular component in serum.

Peritoneal macrophages from Mycobacterium bovis- or Toxoplasma gondii-infected mice cultured in vitro in Dulbecco's medium containing 10% fetal bovine serum (FBS) and endotoxin stopped replication of Cryptococcus neoformans for 30 hr, whereas yeast cells cultured alone reproduced with a 3.0-hr doubling time. Without at least 5% FBS, macrophage fungistasis was poor. FBS without macrophages enhanced the growth rate of cryptococci. Macrophages preincubated in vitro for 24 hr without serum became fungistatic when challenged with cryptococci in medium with FBS but were not fungistatic without FBS. Macrophages preincubated in medium with FBS were never subsequently fungistatic. Dialyzed, heated (56 degrees C, 30 min), or delipidated FBS supported macrophage fungistasis, whereas FBS heated at 70 degrees C for 30 min did not. FBS contained no measurable opsonic activity for C. neoformans. Inclusion of endotoxin and/or murine IFN-gamma over wide concentration ranges did not substitute for FBS. Ultrafiltration estimation of FBS activity localized to 50 to 150 Kd. By gel filtration chromatography, FBS activity ran in the 25 to 100 Kd range. Dye-ligand affinity chromatography on Cibacron blue agarose gel dissociated the FBS activity from the albumin and lipoprotein fractions. Anion-exchange chromatography on DEAE-Sephacel revealed activity in the first fraction eluting at low ionic strength, pointing to a protein(s) with an isoelectric point toward neutral. Activated macrophages can prevent microbial replication within host tissues; the local environment is critical for fulfillment of this important physiologic function. These results point to a macromolecular factor(s) present in serum that is essential for full fungistatic capability of activated macrophages.

Animals↗
PubMed1986

Comparison of itraconazole and fluconazole in treatment of cryptococcal meningitis and candida pyelonephritis in rabbits.

Itraconazole and fluconazole, two new triazoles, were examined for their antifungal activity in rabbits. Fluconazole easily crossed the blood-cerebrospinal fluid barrier, and active drug was eliminated in high concentrations in the urine. On the other hand, itraconazole did not cross the blood-cerebrospinal fluid barrier in measurable amounts, and urine concentrations were variable. Despite differences in pharmacokinetics at the site of infection, both agents were equally effective in treating cryptococcal meningitis and candida pyelonephritis in animals. By using a ketoconazole-resistant strain of Candida albicans, we showed that there was cross-resistance in vivo between these two new triazole compounds.

Animals↗
PubMed1986

Macrophage-mediated fungistasis in vitro: requirements for intracellular and extracellular cytotoxicity.

Macrophage cytotoxicity for Cryptococcus neoformans was investigated by culturing mouse peritoneal macrophages with a thin-capsuled clone of cryptococcus under conditions permitting efficient phagocytosis. Yeast replication was quantitated by electronic particle counting after detergent lysis of macrophages, and viability was determined by quantitative plate counts. Under appropriate conditions, reproduction was completely inhibited; stasis began at 2 hr after addition of yeasts and lasted for 30 hr. During this time organisms in medium alone proliferated rapidly, doubling their number every 2.5 hr. After removal from macrophages, 60 to 100% of macrophage-inhibited cryptococci formed colonies, indicating that the cytotoxic effect was primarily fungistatic. When yeast cells were removed from macrophages, replication recommenced within 5 hr. Supernatant medium from fungistatic co-cultures was not inhibitory for fresh yeast cells. Conditions required for complete fungistasis were 1) peritoneal macrophages induced by peptone from BCG-infected mice, 2) endotoxin in nanogram per milliliter range added to serum-containing cell culture medium, 3) confluent macrophage monolayers, and 4) macrophage:cryptococci ratios of 20 to 100:1. Fungistasis occurred without phagocytosis but was more efficient when cryptococci were engulfed. For efficient fungistasis, macrophages must differentiate to and be maintained in the activated state. These results with yeast cells agree with the known requirements for macrophage effector function against neoplastic target cells.

Animals↗
PubMed1985

Penile cryptococcosis with review of mycotic infections of penis.

A recurrence of cryptococcosis sixteen years after the primary infection as a penile ulcer is reported. The clinical manifestations of genitourinary and skin involvement by cryptococci are discussed. The epidemiology, pathogenesis, diagnosis, and treatment of penile mycotic infections are reviewed.

Amphotericin B↗
PubMed1985

Chemotactic activity of cerebrospinal fluid in experimental cryptococcal meningitis.

Cerebrospinal fluid from rabbits with chronic cryptococcal meningitis was tested for its chemotactic activity towards polymorphonuclear cells and monocytes. CSF chemotactic activity was present; it peaked 5-8 days after infection, coinciding with the time when the number of inflammatory cells in CSF was greatest. However, little chemotactic activity could be found in the early stages of infection, during the initial ingress of inflammatory cells. The chemotactic activity appeared to be host-derived, with characteristics consistent with lymphokine(s) or C5a. Treatment with cortisone significantly reduced the CSF chemotactic activity for both cell types; this reduction may contribute to the severe CSF leukopenia observed in cortisone-treated animals, which are unable to eradicate this yeast infection. Modulation of CSF chemotactic activity may be important to the success or failure of the host central nervous system response to Cryptococcus neoformans.

Animals↗
PubMed1985

Penetration of imidazoles and triazoles into cerebrospinal fluid of rabbits.

We studied the penetration of two imidazoles (ketoconazole and vibunazole) and two triazoles (itraconazole and UK-49,858) into cerebrospinal fluid (CSF) of rabbits with and without meningitis. There were wide differences in degree of penetration of these drugs into CSF, from less than 3% to 66% of simultaneous serum concentrations. UK-49,858, which has little protein-binding, penetrated freely while itraconazole, which is highly protein-bound, could not be detected in CSF. Intermediate concentrations of vibunazole and ketoconazole were found in CSF. Presence of meningeal inflammation modestly increased CSF concentrations of ketoconazole but had no significant effect on penetration of the other three drugs. The excellent penetration of UK-49,858 indicates that it has promise for treatment of CNS fungal infections.

Animals↗
PubMed1985

Comparison of amphotericin B and N-D-ornithyl amphotericin B methyl ester in experimental cryptococcal meningitis and Candida albicans endocarditis with pyelonephritis.

Amphotericin B and N-D-ornithyl amphotericin B methyl ester were compared for therapeutic efficacies against experimentally induced cryptococcal meningitis and Candida albicans endocarditis with pyelonephritis in rabbits. Antifungal activity of the two polyenes in vitro was similar for the yeasts used in these experiments. N-D-ornithyl amphotericin B methyl ester gave a slightly higher concentration in serum than amphotericin B did, but both drugs had similar elimination curves, and penetration into the cerebrospinal fluid was poor for both. Despite these similarities between the two polyenes, amphotericin B was much more effective than N-D-ornithyl amphotericin B methyl ester in the treatment of cryptococcal meningitis in rabbits. For C. albicans endocarditis, both polyenes had similar cure rates, but in vitro measurement of fungicidal activity in serum did not predict treatment outcome. For C. albicans pyelonephritis, both polyenes showed efficacy; because higher doses of the less toxic methyl ester could be used, it sterilized the urinary tract more often than amphotericin B. These studies indicate that in vivo and in vitro experiments may be needed to predict the results of treatment with polyenes.

Amphotericin B↗
PubMed1985

Effects of cyclosporine in experimental cryptococcal meningitis.

We studied the effects of cyclosporine on experimental cryptococcal meningitis. Like cortisone, cyclosporine depressed the highly effective defense mechanisms of normal rabbits against inoculated Cryptococcus neoformans, causing them to develop progressive, fatal cryptococcal meningitis. Unlike cortisone, which causes a striking reduction in leukocytes in cerebrospinal fluid, cyclosporine depressed mononuclear cell function rather than numbers. Interleukin 2, a primary target for the immunodepressive action of cyclosporine, appears to be of central importance in central nervous system defenses against cryptococci. The findings suggest that humans receiving cyclosporine are likely to suffer increased incidence of cryptococcal infection.

Animals↗
PubMed1985

Virulence of Cryptococcus neoformans. Regulation of capsule synthesis by carbon dioxide.

Cryptococcus neoformans is variably encapsulated in vitro, whereas in tissues it develops a large capsule. We observed that cells of a strain with thin capsules, when growing in a standard fungal culture medium, became heavily encapsulated when incubated in serum-free cell culture medium (Dulbecco's modified Eagle's medium [DME]). Capsule size was quantitated physically by measuring cell volume, and chemically by determining the content of a capsular monosaccharide, glucuronate. The CO2/HCO-3 couple stimulated capsule development, resulting in visible enlargement by 3 h after exposure to high CO2/HCO-3. The amount of capsule per cell was directly proportional to the total millimolar CO2/HCO-3 concentration between 24 and 2.4 mM at pH 7.35, but at constant PCO2 (40 torr) and varying [HCO-3], the cells were heavily encapsulated down to pH 6.8. Concentration of CO2/HCO-3 in the physiologic range increased elaboration of polysaccharide into the medium and slowed the cell generation time from 2 to 6 h. Four other first-passage clinical isolates were all heavily encapsulated in DME with CO2/HCO-3, but variably encapsulated in DME without CO2/HCO-3. Exposure of yeast to increased CO2/HCO-3 caused a marked reduction in complement-mediated phagocytosis by mouse macrophages. A stable clone was isolated which contained capsular polysaccharide, but lacked the CO2-inducible phenotype. This clone was avirulent for steroid-treated rabbits. Thus, the prevailing CO2 concentration in mammalian tissues may be one stimulus for capsular polysaccharide synthesis. This could serve as an adaptive mechanism favoring parasite survival in the host.

Animals↗
PubMed1983

Brain abscess caused by a variety of cladosporium trichoides.

A brain abscess caused by a new variety of Cladosporium trichoides occurred in a previously healthy man. A reversed T-suppressor/helper cell ratio was noted as the only immunologic abnormality. He required three surgical procedures, the last an occipital lobectomy, and antifungal chemotherapy to control his disease. He received 2,068 mg of amphotericin B and one year of flucytosine at 6 g per day. Ten months after the last surgery he is without evidence of disease. C. trichoides var. chlamydosporum was isolated from the abscess. It differed from C. trichoides by producing chlamydospores in vitro and only hyphae in the brain abscess. On modified Sabouraud agar, the fungus did not grow at 25 degrees C and grew poorly at 30 degrees C and 37 degrees C. Histologic sections revealed necrosis, no encapsulation, and no epitheliod cells.

Amphotericin B↗
PubMed1983

Pharmacokinetics of N-formimidoyl thienamycin and influence of a renal dipeptidase inhibitor in experimental meningitis.

We studied the pharmacokinetics of N-formimidoyl thienamycin with and without a renal dipeptidase inhibitor in plasma and cerebrospinal fluid (CSF) of rabbits. Thienamycin reached a maximal concentration of 0.6 +/- 0.06 mg/l in the CSF of normal rabbits. When the meninges were inflamed, the mean CSF concentration of N-formimidoyl thienamycin was 3.2 +/- 1.5 mg/l, five times higher than in normal rabbits. This concentration would kill most bacteria that cause meningitis. The renal dipeptidase inhibitor alone had no detectable antibacterial activity. When administered with N-formimidoyl thienamycin, it exerted only minor effects on the pharmacokinetics in either plasma or CSF of normal or infected rabbits.

Animals↗
PubMed1983

Cryptococcemia.

Previous reports have emphasized that cryptococcemia is almost uniformly fatal. To define the clinical course and prognostic and therapeutic implications of cryptococcemia, we studied 15 patients treated at this medical center over the past 7 years. Cryptococcemia was strongly associated with corticosteroid therapy, especially when the dosage had recently been increased. Meningitis was common (but not invariably present) in these patients, characteristically with a large burden of organisms in the cerebrospinal fluid. Cryptococcemia developed during hospitalization in one-third of our patients; this high rate of nosocomial infection emphasizes that C. neoformans infection should be considered in febrile, immunocompromised patients even when the initial work-up is negative. Most of these patients were treated with amphotericin B plus 5-fluorocytosine. Although the one-year survival rate of 4/15 (29%) was dismal, no patient died from uncontrolled cryptococcal infection. Other infections, which developed before, during or after cryptococcemia was diagnosed, were the major immediate cause of morbidity and mortality. The progress of underlying diseases and the outcome of concomitant infections in these patients were more important determinants of survival than was cryptococcemia itself.

Adrenal Cortex Hormones↗
PubMed1983

Fungal peritonitis in patients on continuous ambulatory peritoneal dialysis.

Fungal peritonitis is a rare complication in patients on continuous ambulatory peritoneal dialysis. We report five recent cases and their management. The fungi isolated were Candida albicans, C. parapsilosis, Exophiala jeanselmei, Drechslera spicifera, and a Fusarium species. Chemotherapy was attempted with various regimens including oral ketoconazole, intravenous or intraperitoneal amphotericin B, and oral flucytosine. Pharmacokinetic studies were done in two patients receiving treatment with one of these drugs. Three patients were cured of their fungal infection. Three patients whose Tenckhoff catheters were left in situ died, whereas two patients whose catheters were removed survived. Our experience suggests that removal of the peritoneal catheter should be considered once the diagnosis of fungal peritonitis is established.

Adult↗