Barrett Esophagus.

The authors take a conservative stand on the relationship of Barrett esophagus to adenocarcinoma of the esophagus. They indicate the need for a definitive, large, cooperative, prospective study of all patients who have symptoms and many volunteers who had mild symptoms of esophageal reflux to prove or disprove that relationship.

Immunofluorescence measurement in a flow cytometer using low-power helium-neon laser excitation.

Helium-neon lasers are economical and efficient light sources; their utility in flow cytometry to date has been limited by the lack of fluorescent probes that can be excited at 633 nm. Allophycocyanin (APC), a highly fluorescent phycobiliprotein, can be used as an antibody label and has spectral characteristics suitable for use with He-Ne lasers; we undertook to resolve whether a low-power (7 mW) He-Ne laser could provide sufficient excitation to permit flow cytometric detection of APC-labeled antibodies on cell surfaces. We made an APC conjugate of monoclonal antibody 4F2, which reacts with an antigen abundant on the surfaces of activated human T-lymphocytes; APC-4F2 was used to stain blood mononuclear cells that had been cultured with and without phytohemagglutinin (PHA).

Cell membrane potential changes follow Epstein-Barr virus binding.

Upon binding to receptor-bearing target cells, viruses cause cell membrane potential changes. Epstein-Barr Virus causes a biphasic membrane potential change in receptor-bearing B lymphocytes but not receptor-negative T lymphocytes, as measured by flow cytometry or cyanine dye uptake. Membrane potential changes from EBV binding to receptor-bearing cells resemble electrical responses of other cells following ligand binding to transmembrane receptors.

Chemical inducers of differentiation cause conformational changes in the chromatin and deoxyribonucleic acid of murine erythroleukemia cells.

The chemical inducers of murine erythroleukemia cell differentiation, dimethyl sulfoxide, sodium butyrate, and ethionine, elicited conformational changes in the DNA and chromatin of treated cells. The chromatin from dimethyl sulfoxide treated and butyrate-treated cells exhibited circular dichroic spectra different from that of the noninduced control. The molar ellipticity [theta]282.

Cerebral blood flow during high frequency ventilation in cats.

Cerebral blood flow (CBF) was compared during conventional low frequency ventilation (LFV) [tidal volume 15 ml/kg, respiratory rate 12] and high frequency ventilation (HFV) [tidal volume 3 ml/kg, respiratory rate 100] in normal cats. The intra-arterial 133Xenon technique was used to determine CBF. No significant difference in CBF was present between the 2 groups.

Maintenance of DNA integrity during murine erythroleukemia cell differentiation induced by ethionine and other hypomethylation agents.

The extent of single-strand nicks in DNA from murine erythroleukemia cells induced to differentiate to hemoglobin synthesis in the presence of the hypomethylating agent ethionine was estimated and compared to those levels in uninduced cells and from cells induced to differentiate upon exposure to dimethylsulfoxide or butyrate ion. Although ethionine has been shown to cause more extensive hypomethylation in the DNA of induced cells than that caused by dimethylsulfoxide or butyrate ion, the frequency of detected single-strand breaks in the DNA of uninduced, control cells was not significantly different from that of cells exposed to any of these inducing chemicals. This data indicates that no correlation exists between DNA hypomethylation and DNA single-strand breaks and that unmethylated CpG loci likely do not operate as specific endonuclease recognition sites or as potential origins of transcription in these mammalian cells.

Minimal alveolar concentrations for halothane, enflurane, and isoflurane in the cat.

The minimal alveolar concentrations for halothane, enflurane, and isoflurane in the domestic cat were found to be 1.19 +/- 0.05 (SEM)%, 2.

Ultrasonic evaluation of common bile duct stones: prospective comparison with endoscopic retrograde cholangiopancreatography.

Ultrasound is the modality of choice for the diagnosis of cholelithiasis and for the evaluation of the intra- and extrahepatic biliary tree in the patient with jaundice, but its role in the diagnosis of choledocholithiasis is less certain. We prospectively examined 90 patients who were to undergo endoscopic retrograde cholangiopancreatography (ERCP) by performing right upper quadrant sonography immediately prior to ERCP. We assessed the size of the intra- and extrahepatic ducts and the presence or absence of calculi.

Biological behavior of human breast carcinoma-associated antigens expressed during cellular proliferation.

The cell surface-binding properties of two murine monoclonal antibodies reactive with human mammary tumor cells are described. Fluorescence-activated cell sorter analyses demonstrate that both monoclonal antibodies, B6.2 and B38.

Simultaneous flow cytometric analysis of human T cell activation antigen expression and DNA content.

Cell-surface antigens that are induced to appear on T cells activated by the lectin phytohemagglutinin-P (PHA) can be classified both on the basis of the kinetics of their appearance and on their growth-association properties. Seven distinct T cell activation antigens, defined by monoclonal antibodies, were classified as early, intermediate, or late antigens based on their temporal appearance relative to DNA synthesis. Four antigens, the transferrin receptor, the T cell activation antigen Tac, the 4F2 antigen, and the 49.

Controlled comparison of gentamicin and tobramycin nephrotoxicity.

317 patients with suspected or documented infections other than cystitis were randomly assigned to receive gentamicin or tobramycin dosed according to the Sawchuk/Zaske method or a modification of the McHenry method. 196 patients completed 6 days of therapy, had serial determinations of serum creatinine and were evaluated for nephrotoxicity. Within each dosing method group those patients receiving gentamicin and tobramycin had a similar mean age, initial serum creatinine level, total dose, duration of therapy and trough serum aminoglycoside concentration.

Multistation multiparameter flow cytometry: a critical review and rationale.

The capacity for fluorescence excitation by beams of different wavelengths at separate points along the sample stream, and the capacity for computer analysis of multiparameter data thus obtained, are now available in flow cytometer/sorter systems from commercial producers. It is now readily apparent to most experienced users of flow cytometers that such multiparameter analysis offers the most convenient solution to the problem of characterizing subpopulations of cells within a mixed population. The use of multiple beams facilitates resolution of fluorescence signals from several probes within or upon a single cell and widens the range of analytical alternatives available to experimenters.

A new fluorescent dihydrofolate reductase probe for studies of methotrexate resistance.

A new fluorescent methotrexate analogue (PT430) was synthesized as a reported ligand for dihydrofolate reductase. The analogue was prepared by attachment of lysine in place of the glutamate side chain of methotrexate and conjugation to fluorescein isothiocyanate via the epsilon-amino group of lysine. Spectrophotometric enzyme inhibition assays showed PT430 to be about one-tenth as potent as methotrexate against either Lactobacillus casei or L1210 mouse leukemia enzyme; competitive radioligand binding assays using tritiated methotrexate gave similar results.

Monitoring the effect of anti-cancer drugs on L1210 cells by a mitochondrial probe, rhodamine-123.

The cancer chemotherapeutic agents 1-beta-D-arabinofuranosylcytosine (Ara-C), methotrexate, and 5-fluorouracil cause a rapid loss of mitochondrial Rh-123 uptake in L1210 cells, which correlates with the loss of clonogenic ability. The loss of Rh-123 uptake is irreversible and occurs prior to Trypan Blue staining. Thus, the antimetabolites, unlike freeze-thawing and detergent treatments, generally cause mitochondrial damage prior to changes in plasma membrane permeability.

The neurologic effects of thiopental therapy following experimental cardiac arrest in cats.

To define the utility of high-dose barbiturate therapy following an episode of complete global cerebral ischemia, we investigate the effects of 60 mg/kg of thiopental given to cats five minutes after resuscitation from 12, 14, or 16 min of electrically induced ventricular fibrillation (VF). All aspects of the arrest, resuscitation, with post-arrest care were carefully controlled, with the EEG becoming isoelectric 20-25 s after the onset mean resuscitation time of 2.5 +/- 0.

Intracranial hypertension and brain oedema in albino rabbits. Part 3: Effect of acute simultaneous diuretic and barbiturate therapy.

Increased intracranial pressure due to brain oedema was produced in albino rabbits by combining a cryogenic lesion in the left hemisphere with the intraperitoneal administration of 6-aminonicotinamide (cytotoxic agent). The following parameters were assessed: intracranial pressure (ICP), systolic arterial pressure (SAP), central venous pressure (CVP), EEG, brain water and electrolyte content, gross pathology, and blood brain barrier integrity. Acute therapy to reduce ICP was performed by administering a bolus of mannitol (1 gm/kg) and 30 minutes later, also in bolus, frusemide (5 mg/kg).