Coordinate induction of multiple mRNAs specific for rat liver phenobarbital-inducible cytochromes P-450

Utilizing two-dimensional gel electrophoresis, the polypeptide composition of a purified microsomal cytochrome P-450 preparation isolated from phenobarbital-treated Long-Evans rats obtained from Charles River Laboratories has been examined. The purified protein consists of three polypeptides with nearly identical subunit molecular weights (approximately 52,000) but differing in net charge. These three polypeptides can be detected in liver microsomes isolated from phenobarbital-treated rats by immunoblot analysis but are virtually absent in microsomes isolated from untreated rats. All three polypeptides appear to be products of distinct mRNAs since they can be immunoprecipitated from rabbit reticulocyte lysates programmed with poly(A+)-RNA isolated from phenobarbital-treated rats. The amount of functional mRNA specific for the P-450 polypeptides increases dramatically in response to an acute administration of phenobarbital; however, in untreated rats the amount of functional mRNA was below the level of detection by the translational assay. These data are consistent with the very low level of the phenobarbital-inducible cytochromes P-450 in liver microsomes isolated from untreated rats. Finally, the data indicate that all three cytochrome P-450 mRNAs increase rapidly in response to phenobarbital administration and are regulated coordinately.

Senile dementia and hydrocephalus due to carotid dolichoectasia

A 65-year-old hypertensive man presented with progressive dementia, and bilateral lower limb weakness. Computerised tomography revealed carotid arterial dolichoectasia and hydrocephalus. This uncommon entity may constitute another form of surgically treatable dementia in the elderly.

Novel applications of monoclonal antibodies

The ability to "engineer" antibodies, using the techniques of somatic cell genetics and cell fusion, has opened a new era in immunochemistry. No longer are immunologists, limited by the vagaries of polyclonal antibody production. Using hybridoma technology, consistent preparations of precisely defined monoclonal antibodies are now available. Immunochemists are free to pick and choose those precisely defined characteristics of a homogeneous species of antibody that are best suited for a given application. To date, monoclonal antibodies have been used primarily as research chemicals. However, the implications of this new technology for diagnostic, therapeutic, and separation systems are rapidly becoming apparent.

Two-dimensional echocardiographic features of Björk-Shiley aortic prosthetic valve dehiscence

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Monoclonal antibodies in clinical immunology

Advances in clinical immunodiagnostics resulting from the application of hybridoma technology are starting to appear. Monoclonal antibodies are beginning to displace their antiquated progenitors, polyclonal antisera, in many facets of immunology. Their homogeneity, specificity, and availability make hybridoma-derived antibodies the immunological reagents of the future in immunoassays, immuno-affinity chromatography, immunotherapy, and areas yet to be defined.

Monoclonal antibodies in clinical immunology

Advances in clinical immunodiagnostics resulting from the application of hybridoma technology are starting to appear. Monoclonal antibodies are beginning to displace their antiquated progenitors, polyclonal antisera, in many facets of immunology. Their homogeneity, specificity, and availability make hybridoma-derived antibodies the immunological reagents of the future in immunoassays, immuno-affinity chromatography, immunotherapy, and areas yet to be defined.

The hybridoma-an immunochemical laser

The advent of hybridoma technology has provided the immunotechnologist a finely tunable instrument that should permit a marked advance in the immunologic sciences. The ability to choose the precise antibody required and the virtually unlimited availability of easily purified antibodies have already resulted in the simultaneous immunometric assay and potential reagents for immunoscintigraphy and immunotherapy. Using an antibody with a specific affinity and recognition for a specific antigenc determinant can greatly influence the shape and range of a radioimmunometric calibration curve. With monoclonal antibodies, assay systems based on immune complexes (e.g., turbidimetric assays and counterimmunoelectrophoresis) can be made more precise, thus permitting study of the basic physicochemical principles underlying the antigen-antibody reaction and the development of greatly improved quantitative assays. On the other hand, the ability to select an antibody exhibiting specific characteristics implies the necessity to select. One no longer has the luxury of using a mixture of antibodies, hoping to take advantage of the fact that some will have desirable secondary characteristics such as electrophoretic mobility or the ability to absorb to plastics.

The hybridoma-an immunochemical laser

The advent of hybridoma technology has provided the immunotechnologist a finely tunable instrument that should permit a marked advance in the immunologic sciences. The ability to choose the precise antibody required and the virtually unlimited availability of easily purified antibodies have already resulted in the simultaneous immunometric assay and potential reagents for immunoscintigraphy and immunotherapy. Using an antibody with a specific affinity and recognition for a specific antigenc determinant can greatly influence the shape and range of a radioimmunometric calibration curve. With monoclonal antibodies, assay systems based on immune complexes (e.g., turbidimetric assays and counterimmunoelectrophoresis) can be made more precise, thus permitting study of the basic physicochemical principles underlying the antigen-antibody reaction and the development of greatly improved quantitative assays. On the other hand, the ability to select an antibody exhibiting specific characteristics implies the necessity to select. One no longer has the luxury of using a mixture of antibodies, hoping to take advantage of the fact that some will have desirable secondary characteristics such as electrophoretic mobility or the ability to absorb to plastics.

Diffuse reflectance of retinal tapeta lucida, with special reference to drums (Sciaenidae)

Reflection of light by ocular tapeta lucida of drums (Sciaenidae) was studied in Cynoscion arenarius Ginsburg, C. nebulosus (Cuvier), Micropogon undulatus (L.) and Leiostomus xanthurus Lacèpéde. The tapetum is located in the pigment epithelium of the eye, is matt white, and behaves as a uniform diffuser. The pigment epithelium contains densely packed tapetal spheres; these are randomly arranged, have a diameter of about 0.4 μm and contain a lipid that has a refractive index of 1.50. Because of their dense packing they backscatter much of the incident light. Diffuse reflectance is about 50%. Measured values of reflectance are compared with those computed for a model system having the same physical characteristics, and they are in good agreement. The optical density of the visual pigment at the wavelength of maximal absorption (λ 510 nm) is 0.33, and the tapetum increases light absorption in the dark-adapted eye by a factor of 1.3. Reflectance of croaker tapetum is compared with reflectances of tapeta of Lepisosteus, Arius, and Notopterus afer, which contain different reflecting materials.

Treatment of chronic atrial fibrillation in the elderly, assessed by ambulatory electrocardiographic monitoring

This study concerns 8 elderly patients with age-related chronic atrial fibrillation that required control of the ventricular response. The effects of oral administration of placebo, pindolol, verapamil, digoxin and digoxin + pindolol were assessed (each for a week) during three daily activity and sleep sessions, over a six-week period. Cardiac rhythm was monitored by taped electrocardiograms. Either digoxin or pindolol was effective, but digoxin was the best tolerated of all the drugs. A combination of pindolol and digoxin reduced the maximum ventricular rate without further depression of the minimum ventricular rate. Digoxin seems to be well tolerated in the control of atrial fibrillation in the elderly, and beta blockade may be a useful therapeutic adjunct.

Suppression of long-standing incessant ventricular tachycardia by amiodarone

A 25 year old man had experienced virtually incessant ventricular tachycardia since the age of 16 years, and complained of increasing lethargy and shortness of breath over the past 5 years. Despite medical therapy with numerous conventional antiarrhythmic agents, no single drug or combination of drugs had successfully controlled the tachycardia. Isotope and contrast angiography revealed an enlarged left ventricle with poor function. Electrophysiological studies demonstrate earliest endocardial activation at the left ventricular apex. No electrical procedure terminated tachycardia. Following institution of amiodarone, continuous ECG monitoring revealed periods of sinus rhythm alternating with periods of ventricular bigeminy. Repeat isotope angiography indicated a considerable improvement in L.V. function. There was a corresponding reduction in heart size on the chest radiograph. Clinical improvement was evidenced by disappearance of lethargy and shortness of breath. This report demonstrates that amiodarone, a new antiarrhythmic agent, may suppress long standing incessant ventricular tachycardia resistant to other antiarrhythmic agents. The marked reduction in heart size on amiodarone may suggest that the associated cardiomegaly is secondary to tachycardia.

A simplified solid-phase immunofluorescence assay for measurement of serum immunoglobulins

A simple 2-step solid-phase fluoroimmunoassay for the determination of serum immunoglobulins is described. The method employs a stabilized solid-phase immunoadsorbent consisting of antigen immobilized on a cellulose acetate/nitrate disc attached to a plastic StiQTM sampler. The polymeric disc serves both as a substrate for immobilization and as a highly uniform surface upon which very precise fluorescence determinations may be made. The assays rely upon the reaction of a precise and limiting amount of mono-specific fluorescent antibody with the specific antigen present in a test sample. Residual unreacted fluorescently labeled antibody is allowed to bind to the immunoadsorbent; non-specifically bound antibody is removed in a wash step. The amount of labeled antibody bound is inversely proportional to the amount of antigen present in the test sample. The fluorescence of the bound labeled antibody is measured using a FIAX surface-reading fluorometer. Comparison of this new procedure with the commercially available (4-step) FIAX assay, which requires generation of immunoadsorbent in situ, demonstrated excellent correlation between the two methods. The new 2-step procedure provides results in a much shorter period of time and requires one-half to one-eighth of the operator time required for the other available solid-phase fluoroimmunoassays.

Semi-automatic solid-phase radioimmunoassay for carcinoembryonic antigen

A solid phase, double antibody radioimmunoassay has been semi-automated for the quantitation of carcinoembryonic antigens. Sepharose-bound rabbit anti-goat IgG immunoglobulin was used as the second antibody, reactions were carried out in 96-well microtiter plates, and samples processing (filtration and washing) was accomplished with the aid of a 24-sample harvester.

Nursing in China

Nursing in China is described in this article in relation to training, selection of candidates and duties of these professionals.

Human-mouse hybrid cell lines and susceptibility to polio virus. II. Polio sensitivity and the chromosome constitution of the hybrids

A number of human-mouse hybrid cell lines with partial human chromosome complements were sensitive to poliovirus because the cells contained the viral receptor substance of human origin. Infection of the lines with one type of poliovirus regularly led to the survival of a few cells, whose progeny were found to be resistant to all types of poliovirus. Comparison of the chromosomes of sensitive hybrids and their resistant sublines showed no consistent difference in the number of biarmed human chromosomes of any group. The number of acrocentrics was always lower in the resistant hybrids than in the corresponding sensitive lines. It is suggested that the human chromosome bearing the polio receptor gene is an acrocentric.

Human-mouse hybrid cell lines and susceptibility to poliovirus. I. Conversion from polio sensitivity to polio resistance accompanying loss of human gene-dependent polio receptors

A number of human-mouse somatic hybrid cell lines have been prepared, containing from 3 to 12 human biarmed chromosomes. These lines were susceptible to poliovirus type 1, producing viral yields comparable to those of the human parental cells. A small proportion of the cells of these lines survived the polio infection, and their progeny were solidly resistant to reinfection with the virus. Both sensitive and resistant hybrids produced virus following infection with viral ribonucleic acid, indicating that the cytoplasm of the resistant hybrids was able to support viral multiplication. Viral adsorption studies carried out at 4 C showed that the resistant sublines had negligible ability to adsorb the virus. It was concluded that the hybrid cells became resistant to polio through loss of the human chromosome bearing the gene for the receptor substance.