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Biomedical subjects

R Nachum

Publications and source records attributed to R Nachum.

At least 19 recordsLinked to original sources
PubMed1998

Vancomycin-resistant enterococcal colonization in nonhospitalized HIV-infected patients.

We studied fecal colonization with vancomycin-resistant enterococci (VRE) in 89 HIV-infected nonhospitalized patients ages 24 to 62 years, including 70 (79%) men (including 41 homosexual and 5 bisexual men) and 19 (21%) women. Of the 89 patients, 61 (69%) were black, 25 (28%) Hispanic, and 3 (3%) white; 53 (60%) had history of ongoing or recent antibacterial therapy with trimethoprim/sulfamethoxazole (29), clarithromycin (18), amoxicillin (7), ofloxacin (3), and metronidazole, doxycycline, dicloxacillin, and cephalexin (1 each). VRE were not isolated from any of the patients studied.

AIDS-Related Opportunistic Infections↗
PubMed1995

Chronic Q fever of pregnancy presenting as Coxiella burnetii placentitis: successful outcome following therapy with erythromycin and rifampin.

Chronic Q fever has been associated with endocarditis, granulomatous hepatitis, and osteomyelitis but only rarely with pregnancy. The apparent predilection of Coxiella burnetii, the organism causing Q fever, for the human placenta suggests that chronic Q fever of pregnancy is due to placentitis. We describe a patient with chronic, clinically apparent Q fever in pregnancy and a successful outcome. The diagnosis was made both by serology and by isolation of C. burnetii from the patient's serum and placenta. Therapy with erythromycin and rifampin contributed to the delivery of a healthy baby. The mother's infection was clinically cured by subsequent therapy with doxycycline and rifampin.

Adult↗
PubMed1987

Usefulness of LAL assay for rapid detection of gram-negative bacteriuria.

LAL assay is a rapid and reliable and easy to perform and interpret urine screen for clinically significant gram-negative bacteriuria. Chromogenic assays are rapid (5 min) and obviate problems associated with gel endpoints, such as inadvertant dissolution of the gel, either during incubation or reading. LAL urine screening is characterized by both high positive and negative predictive values. LAL urine assay identifies gram-negative urinary tract infections by measuring urine endotoxin content as an index for significant numbers of urinary tract pathogens, thus eliminating large numbers of false-positive tests characteristic of other urine screening methods. Screening urine for greater than or equal to 10(5) CFU/ml appears to be an acceptable criterion for defining a UTI in patient populations with low prevalence rates (2-10%). Thus, LAL urine assay may have potential usefulness for screening of asymptomatic populations, such as pregnant women and the elderly.

Bacteriuria↗
PubMed1986

Establishment of beta-hydroxy fatty acids as chemical marker molecules for bacterial endotoxin by gas chromatography-mass spectrometry.

Selected ion-monitoring gas chromatography-mass spectrometry was used for detection of beta-hydroxy fatty acids as an independent assay for the presence or absence of endotoxin in materials claimed to induce nonspecific activation of Limulus amoebocyte lysate. To this end, suspensions of gram-negative and -positive bacteria, one fungal species, cerebrospinal fluid, and hollow-fiber hemodialyzer rinses were assayed for endotoxin by gas chromatography-mass spectrometry and the Limulus amoebocyte lysate assay. Good qualitative agreement was shown for both methods when suspensions of test organisms were assayed. Two false-negative results were obtained by gas chromatography-mass spectrometry assays of cerebrospinal fluid and were shown to be a result of insufficient endotoxin in the cerebrospinal fluid specimens for detection by gas chromatography-mass spectrometry. Hemodialyzer rinses were Limulus assay positive; however, no beta-hydroxy fatty acids were detected by gas chromatography-mass spectrometry. These data were compared with data obtained from USP rabbit pyrogen tests of the rinse materials (nonpyrogenic) and chemical characterization of the Limulus assay-reactive rinses, which showed the rinses to be cellulosic in nature. It is suggested that beta-hydroxy fatty acids, as assayed by selected ion-monitoring gas chromatography-mass spectrometry, be used as chemical marker molecules for the presence or absence of endotoxin in materials reported to cause nonspecific activation of Limulus amoebocyte lysate.

Candida albicans↗
PubMed1986

Gram-negative bacteriuria of pregnancy: rapid detection by a chromogenic Limulus amoebocyte lysate assay.

A chromogenic Limulus amoebocyte lysate assay, performed at room temperature, was evaluated for rapid detection (five minutes) of asymptomatic bacteriuria of pregnancy. Development of a distinctive yellow color was used to detect urines containing greater than 10(5) gram-negative bacteria per milliliter. One thousand thirty-nine urine samples were obtained from 664 obstetric patients, with 86 of the specimens shown to contain greater than 10(5) gram-negative urinary tract pathogens. Of these, 74 of 86 were detected by chromogenic Limulus assay; 11 false-positive tests were recorded. At a urine dilution of 1:10, sensitivity and specificity were 88.7 and 98.7%, respectively. Predictive values, based on an attack rate of 10%, were 98.6% for a negative test and 89.9% for a positive test. These data suggest that chromogenic Limulus amoebocyte lysate assay of urine has potential usefulness as a rapid, reliable, and easily performed and interpreted screening test for asymptomatic bacteriuria of pregnancy.

Bacteriuria↗
PubMed1986

Campylobacter jejuni septicemia--epidemiology, clinical features and outcome.

In 33 cases of Campylobacter jejuni septicemia, the disease was more common at the extremes of age: infants made up a third of the reported cases while 24% of patients were older than 50 years. Fever was noted in more than 80% of patients and chills in about a fourth. Enteritis was present in 70% of cases, and the gastrointestinal tract was the principal source of septicemia. Half of the patients did not have significant underlying disease but were at extremes of age, which may reflect relative host impairment. Mortality (25%) owing to C jejuni septicemia occurs mostly in compromised hosts.

Age Factors↗
PubMed1985

Chromogenic Limulus amoebocyte lysate assay for rapid detection of gram-negative bacteriuria.

A chromogenic Limulus amoebocyte lysate assay was evaluated as a rapid screening test for the detection of clinically significant gram-negative bacteriuria. The development of a distinctive yellow color after the addition of chromogenic substrate to the Limulus amoebocyte lysate-urine reaction mixture was used to measure greater than or equal to 10(5) gram-negative bacteria per ml. A total of 324 urine specimens were assayed, with 68 gram-negative urinary tract infections identified as defined by quantitative urine colony counts of greater than or equal to 10(5) bacteria per ml. Of these, 68 and 67 of 68 were detected by the chromogenic Limulus amoebocyte lysate assay at urine dilutions of 1:10 and 1:20, respectively. Nine false-positive chromogenic Limulus amoebocyte lysate assay results were observed at both urine dilutions and in the same specimens. At a urine dilution of 1:10, sensitivity and specificity were 100 and 96.6%, respectively, with predictive values of 100% for a negative test and 88.3% for a positive test. At a urine dilution of 1:20, sensitivity and specificity were 98.6 and 96.6%, respectively; predictive values were 99.6% for a negative test and 88.3% for a positive test. These data suggest that chromogenic Limulus amoebocyte lysate assay of urine has potential usefulness as a rapid, reliable, and easily performed and interpreted screening test for the diagnosis of clinically significant gram-negative bacteriuria.

Bacteriuria↗
PubMed1983

Cerebral chromomycosis.

A 52-year-old man was admitted to the hospital with headache, confusion, and early papilledema. He was receiving prednisone and azathioprine for interstitial pulmonary fibrosis. A right temporoparietal cerebral abscess was diagnosed by computed tomographic scan, brain scan, and cerebral angiography. Fungal cultures of pus obtained at operation grew a pigmented fungus, Cladosporium trichoides. Three additional abscesses were found in the right cerebellar hemisphere at autopsy after the patient died of an unrelated cause. Chromomycosis occurring at sites other than skin is extremely rare. No lesions were detected outside the CNS in our patient. C trichoides has not been previously recognized as an agent causing disease in compromised hosts.

Brain Diseases↗
PubMed1981

Rapid detection of Gram-negative bacteriuria by Limulus amoebocyte lysate assay.

The Limulus amoebocyte lysate (LAL) test was evaluated for rapid detection of gram-negative bacteriuria in an adult patient population. Time to gelation of a standard LAL preparation was used as a measure of significant (greater than 10(5) bacteria per ml) gram-negative bacteriuria, and the results of 190 LAL assays were compared with quantitative urine cultures. Initially, 33 of 36 urine specimens containing greater than 10(5) gram-negative bacteria per ml were detected by LAL assay. The three false-negative LAL tests were the result of urine pH levels below the pH minimum for LAL gelation; neutralization of these urine specimens resulted in positive LAL assays and 100% correlation with culture results. All 36 bacteriuric urine specimens were LAL positive within 15 min, with the majority of assays (86.1%) being positive after only 10 min of incubation at 37 degrees C. These data compared favorably with gelation times of 15 min when 1 X 10(5) to 2 X 10(5) gram-negative bacteria per ml were added to sterile urine. Two urine samples obtained from male patients with culture-proven gonococcal urethritis yielded positive LAL assays. The LAL assay was shown to correctly differentiate 96.2% of urine specimens as containing less than 10(5) or greater than 10(5) gram-negative bacteria per ml. The results of this study have shown that the LAL test can be used as a rapid, simple, and reliable screening procedure for the diagnosis of clinically significant gram-negative bacteriuria.

Adult↗
PubMed1976

Cerebrospinal fluid endotoxin concentrations in gram-negative bacterial meningitis.

The limulus lysate assay was utilized to detect and quantitate endotoxin in cerebrospinal fluid from 232 patients with suspected meningitis. The assay was positive in initial specimens of CSF from all 86 patients with gram-negative bacterial meningitis and was uniformly negative in the remaining 146 patients with a variety of infectious and noninfectious processes. Endotoxin concentrations in initial specimens of CSF from patients with gram-negative meningitis ranged from 4 to 2,000 ng/ml. No correlation between initial CSF levels of endotoxin and initial clinical or laboratory variables of infection was noted. With antibiotic therapy, CSF concentrations of endotoxin fall rapidly to undetectable levels after five days.

Adult↗
PubMed1976

Detection of bacterial endotoxin in antitumor agents.

The Limulus amebocyte lysate assay was used to detect the presence of bacterial endotoxin in a variety of chemotherapeutic agents currently in use. Results were quantitated using a standard Escherichia coli endotoxin curve. Relative concentrations of endotoxin ranging from 0.1 to 63 ng/ml were detected in individual lots of L-asparaginase, 5-azacytidine, bleomycin, DTIC, actinomycin D, adriamycin, and vinblastine diluted to normal concentrations for injection. When multiple lots of a given drug were tested, at least one lot produced a negative assay, indicating less than 0.1 ng/ml of endotoxin in 50% of these drugs. All lots of cytosine arabinoside, cyclophosphamide, daunorubicin, vincristine, and streptozotocin tested had less than 0.1 ng/ml of endotoxin. Inactivation kinetics of the Limulus-positive drug material in dilute alkali solutions were identical to those of E. coli endotoxin. The Limulus lysate test is a rapid and specific method for the detection of small amounts of bacterial endotoxin contaminating parenteral preparations of antitumor agents.

Animals↗