Stimulant properties of bromocriptine on central dopamine receptors in comparison to apomorphine, (+)-amphetamine and L-DOPA

1. The activity of bromocriptine has been investigated in tests for the stimulation of central dopaminergic mechanisms. The results obtained have been compared with those of apomorphine, (+)-amphetamine and L-DOPA. 2. Bromocriptine (2.5 to 10 mg/kg) induced stereotyped sniffing and licking in rats. The stereotypy was more intense than that induced by L-DOPA and less intense than that of apomorphine and (+)-amphetamine over the dose ranges studied. 3. In rats lesioned unilaterally in the substantia nigra by local injection of 6-hydroxydopamine, bromocriptine, like apomorphine and L-DOPA, induced turning contralateral to the side of the lesion. The smallest dose of bromocriptine to induce turning was 0.5 mg/kg. 4. Reserpine-induced catalepsy in mice was antagonized by bromocriptine, with an ED50 of 1.8 mg/kg. It was intermediate in potency to apomorphine and L-DOPA. 5. Spontaneous locomotor activity in mice was stimulated by bromocriptine in a dose-dependent manner from 2.5 to 10 mg/kg after an initial suppression of activity. 6. In all experiments, bromocriptine was characterized by a prolonged duration of activity after a delay in the onset of effect. 7. The stereotyped behaviour induced by bromocriptine was inhibited by prior administration of pimozide, reserpine or alpha-methyl-p-tyrosine. 8. Bromocriptine-induced turning behaviour was abolished by pretreatment with pimozide, and reduced after alpha-methyl-p-tyrosine treatment. 9. The results obtained support the conclusion that bromocriptine acts by stimulating dopamine receptors in the central nervous system and that intact catecholamine synthesis and granular amine storage mechanisms are necessary for it to bring about its effects.

Genetic typing of alpha1-antitrypsin by immunofixation electrophoresis, identification of subtypes of Pi M

Prolonged electrophoresis in alkaline agarose gels, followed by immunofixation, is a valuable addition to acid starch gel electrophoresis and isoelectric focusing for the genetic phenotyping of alpha1-antitrypsin. This technique is helpful in clarifying certain variants and in ascertaining types in serum and amniotic fluid samples with secondary changes. In addition, heterogeneity may be detected within the variants found at pH 4.95, analogous to hemoglobin polymorphism. Two "new" variants, PiMLamb and PiMBaldwin, have been detected by a combination of immunofixation electrophoresis and acid starch gel electrophoresis.

Variants of the group-specific component system as demonstrated by immunofixation electrophoresis. Report of a new variant, Gc Boston (Ge B)

Immunofixation electrophoresis is a relatively simple and reliable method for the genetic phenotyping of the group-specific component (Gc) of serum. This method permits direct comparison of electrophoretic mobilities and band concentrations, with no interference by other proteins. The variants Gc Ab and Gc Y appear identical by this technique; the Eskimo variant appears to be similar to Gc D but not to Gc Ab as previously reported. Gc Norway, also designated Gc 1C, is electrophoretically cathodal to the slower band of Gc 1 and therefore appears to be a distinct variant. A new variant, Gc Boston, is single banded with mobility between the two bands of Gc 1.

Protease inhibitors in chronic obstructive pulmonary disease

Quantification of the major plasma protease inhibitors and genetic typing of alpha1-antirypsin were done in 107 patients with chronic obstructive pulmonary disease and in 91 control subjects with normal ventilatory function who were similar with respect to age, race, and sex. There was a significant increase in frequency of the PiZ gene and the Pi MZ phenotype of alpha1-antitrypsin among the patients when compared with the control subjects. No evidence for a primary deficiency of any other antiprotease was found; however, the mean concentration of inter-alpha-trypsin inhibitor was significantly lower in the patients than the control subjects, and moderate deficiency of alpha1-antichymotrypsin was noted in a few patients. These data indicate an increased risk of developing chronic obstructive pulmonary disease in persons with the Pi MZ phenotype of alpha1-antirypsin and suggest a possible relationship between these diseases and low serum concentrations of inter-alpha-trypsin inhibitor.

Factors affecting the changes in amphotericin sensitivity of Candida albicans during growth

The sensitivity of Candida albicans, grown in batch culture at 37 degrees C, to amphotericin methyl ester (AME), judged by the concentration of AME required to induce a standard rate of leakage of K+ from suspensions of organisms, decreased with the time of growth. Organisms in exponential growth were sensitive to 0-I to 0-2 mug AME/ml while organisms in the stationary phase were resistant to 4 to 60 mug AME/ml, depending on the initial concentration of glucose in the medium and the length of time for which incubation had been continued. When the initial concentration of glucose was low (0-I%, w/v), the AME resistance rose during the early stationary phase and then, after 40 h incubation at 37 degrees C, decrease again. Sphaeroplasts were prepared from organisms at different phases of growth and did not show these changes in AME sensitivity, but remained highly sensitive for growth up to 40 h. Sphaeroplasts were prepared by treating suspensions of organisms with mercaptoethanol and then digesting with Streptomyces enzyme preparation. Addition of the material extracted by the digestion to suspensions of exponential-phase organisms or sphaeroplasts increased their AME resistance. Fractionation of the digest showed that the antagonistic material was contained in the neutral lipid fraction. Pure lipids fell into the following order of decreasing antagonism to AME when added together with the antibiotic to suspensions of exponential-phase organisms: sterol esters (ergosterol esters greater than cholesterol esters; unsaturated fatty acid esters greater than saturated fatty acid esters), sterols, triglycerides, unsaturated fatty acids, saturated fatty acids. The amount of antagonistic material released from stationary organisms was not markedly greater than that from exponential-phase organisms and analysis of the lipid content of wall preparations showed that the content of total lipid, neutral lipid and triglyceride of 40 h organisms was not more than 75, 25 and 30%, respectively, greater than that of exponential-phase organisms. The AME resistance of stationary-phase organisms decreased rapidly if suspensions were incubated with glucose or mercaptoethanol. The decrease in the presence of glucose was prevented by metabolic inhibitors, especially SH binding agents. Treatment of organisms with either iodoacetamide or N-ethylmaleimide gave a rapid increase in AME resistance, amounting in some cases to 5- to 15-fold. The effect of iodoacetamide decreased as the organisms passed into the stationary phase and their intrinsic resistance increased. Evidence is presented which suggests that the degree of reduction of SH groups in the cell surface is an important factor in determining AME resistance.

Calorimetric studies of the role of magnesium ions in yeast enolase catalysis

The binding of magnesium ions and of the competitive inhibitor 3-phospho-D-glyceric acid to yeast enolase (2-phospho-D-glycerate hydrolyase, EC 4.2.1.11) has been studied calorimetrically. Thermal titration of the apoprotein with magnesium ions provides evidence that two magnesium ions bind immeasurably tightly to the dimeric enzyme, either anticooperatively to interacting sites or to two independent, nonidentical sites. Measurements of the saturation heat in buffers with different enthalpies of protonation are consistent with the release of two protons when the metal-binding sites are filled at pH 7.5. The enthalpy of binding of the two magnesium ions, corrected for the release of two protons, is +11.7 kcal (+49.0 kJ) per mole of dimeric protein. Thermal titration of the magnesium-saturated enzyme with 3-phosphoglyceric acid corroborates the conclusion of Spring and Wold [Biochemistry (1971) 10, 4655-4660] that the enolase dimer possesses two equivalent and independent substrate-binding sites. The dissociation constant for the enzyme-inhibitor complex calculated from the thermal data is 2 mM. The thermal studies of 3-phosphoglyceric acid binding also confirm that metal ions are required for substrate binding and that substrate binds at the two specific metal-binding sites on the apoprotein. Experiments in buffers with different enthalpies of ionization provide evidence for proton uptake when 3-phosphoglyceric acid is bound.

Saccular aneurysm caused by bacterial endocarditis in a syphilitic aorta

Robinson, W.M., McMillan, I.K.R., and Johnson, A. M. (1973). Thorax, 529-532. Saccular aneurysm caused by bacterial endocarditis in a syphilitic aorta. The rapid development of a saccular aneurysm during successfully treated bacterial endocarditis, in an ascending aorta previously affected by syphilis which had been treated with adequate chemotherapy 15 years previously, is described. Although bacterial endocarditis does occasionally complicate syphilitic aortic valve disease, the literature does not contain any report of resulting aneurysm development. The investigation and successful surgical treatment of the case are described.

C1 inhibitor: evidence for decreased hepatic synthesis in hereditary angioneurotic edema

Although the Cl inhibitor was detected in 5 to 10 percent of normal hepatic parenchymal cells by means of the immunofluorescent technique, none was seen in liver biopsies from two individuals with hereditary angioneurotic edema having low concentrations of Cl inhibitor in the serum. In contrast, the percentages of cells which reacted with fluorescent antiserums to C4 and transferrin were normal. These data suggest that in most subjects with hereditary angioneurotic edema, there is decreased synthesis of the C1 inhibitor but normal synthesis of C4, and that the disease results from this biosynthetic error.

Herniation of the heart

Five cases of herniation of the heart are described, of varying aetiology and presentation. In one, the pericardial deficiency is congenital. Two are traumatic—one with severe disruption of the rib cage, and one without. Two are post-operative—one early, and one late. Their aetiology, diagnosis and treatment are discussed. If the possibility of herniation is considered, the diagnosis may often be made from a plain chest radiograph. The treatment is operative, and may give relief from a critical circulatory embarrassment.

Inheritance of human alpha-1-acid glycoprotein (orosomucoid) variants

Although variants of sialic acid-free alpha(1)-acid glycoprotein have been described in human beings, the mode of inheritance of these types has not been reported previously. With the use of a new technique of immunofixation after agarose gel electrophoresis of neuraminidase-treated whole serum, the present study demonstrates that the types of alpha(1)-acid glycoprotein variants in family members are consistent with inheritance as autosomal traits with codominant expression. Gene frequencies have been determined for several ethnic groups. Of a total of 11 maternal-cord serum pairs, seven were discordant types, indicating that the fetus synthesizes alpha(1)-acid glycoprotein and confirming a previous report that there is no significant transplacental passage of this protein.

Photocoagulation delivery systems for continuous-wave lasers

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Human C'3: evidence for the liver as the primary site of synthesis

The liver is the primary, if not sole, site of synthesis of the third component of human complement, as shown by a change in the recipient from C'3 FS(0.6) to C'3 SS, the donor type, following homotransplantation of the liver.

Genetic differentiation of pathogenic and nonpathogenic strains of Entamoeba histolytica by random amplified polymorphic DNA polymerase chain reaction

The random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) method was used to compare pathogenic and nonpathogenic strains of Entamoeba histolytica. DNA polymorphisms were detected among the different strains and dendrograms were constructed by PHYLIP and PAUP analyses to study the relationship of the strains. Both analyses resulted in identical results, which indicated that pathogenic strains of E. histolytica are closely related and clearly separated from the nonpathogenic strains. The results of this study agree with classification of the strains based on isoenzyme analyses. This suggests that RAPD-PCR is a valuable method in differentiating between strains of this parasite, and the results are consistent with the concept that pathogenic and nonpathogenic Entamoeba represent two different species.