Autoradiographic study of the alpha-adrenoceptors of rat aorta and tail artery.
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Animals↗
Biomedical subjects
M Jacobs
Publications and source records attributed to M Jacobs.
The effect of isoprenaline on the ciliary activity of an in vitro preparation of rat trachea.
A dose dependent increase in the ciliary beat frequency of rat tracheal explants was found over a 10(-7)-10(-3) M concentration range of (+/-)-isoprenaline and was abolished by 10(-7) M propranolol. Furthermore (+)-isoprenaline, a drug which is much less potent in its action on beta-adrenoceptors than its (-)-isomer, failed to cause a stimulation. We conclude that the acceleration in the intrinsic ciliary beat frequency by (-)-isoprenaline, although occurring at a relatively high concentration compared with the action of the drug on other tissues, is mediated by beta-adrenoceptors.
Animals↗
Relationship between changes in plasma lipoprotein concentrations and fecal steroid excretion in man during consumption of four experimental diets.
Limited information is available on the mechanism by which changes in nutrient intake influence plasma lipids. We compared the effects on plasma lipoprotein levels of 3 dietary modifications involving changes in total fat intake (27-40% of calories), cholesterol intake (100-250 mg/1000 kcal), the dietary polyunsaturated to saturated fatty acid ratio (0.3-1.0) and intake of vegetable-derived fiber and protein. On these 3 diets, plasma low density lipoprotein was reduced by 26-34%. Fecal bile acid excretion was similar on all diets (363-379 mg/day). There was no alteration in fecal bile acid output associated with an increase in polyunsaturated or total fat intake. Sterol balance became significantly more negative during consumption of only 1 of the 3 cholesterol-lowering diets. The observed reduction in plasma cholesterol levels was not associated with an increase in fecal bile acid output suggesting that diet-induced changes in circulating cholesterol are not maintained by an increase in sterol turnover but may reflect alterations in hepatic cholesterol and lipoprotein synthesis.
Adult↗
Violent or fear-inducing behavior associated with hospital admission.
Recent studies indicate that the incidence of violent or fear-inducing behavior among the mentally ill may be higher than once thought. In this study, medical record admission notes for 1,687 psychiatric patients over a four-year period were examined for indications that the patients had engaged in violent or fear-inducing behavior just prior to hospital admission. This and other studies suggest that the frequency of violent or fear-inducing behavior associated with psychiatric admissions may have stabilized in recent years. The authors also found a significantly higher level of hospital readmissions for violent patients than for other patients. As a result, they caution against assuming that the rate of violent behavior among hospital admissions accurately reflects the prevalence of violent behavior among the general population of the mentally ill.
California↗
Multiple molecular forms of prolactin during pregnancy in women.
The distribution of isomorphic forms of prolactin in the serum of pregnant women was studied by gel filtration chromatography. Using this technique we were able to resolve three peaks, detected by radioimmunoassay: they were termed 'big-big', 'big' and 'little' prolactin in order of decreasing size, with approximate molecular weights greater than 100 000, 50 000 and 21 000 respectively. They displayed a comparable immunoreactivity to the antiserum employed in the radioimmunoassay, as determined in competition experiments. The relative amount of each hormone form in serum changed during the third trimester of pregnancy. At week 33 of pregnancy, 'little' prolactin accounted for 63.2 +/- 7.7% of the total circulating hormone present in the serum of five normal pregnant women. During the progression of pregnancy, there was a gradual increase in the low molecular weight prolactin, so that, at the time of delivery, the larger forms of the hormone were present only in small amounts.
Adult↗
A retrospective study of head-injured children admitted to two hospitals in Cape Town.
A retrospective study was undertaken to describe the patterns of head injury in children in the Cape Peninsula. Information was abstracted from Groote Schuur Hospital and Red Cross War Memorial Children's Hospital records for all children aged under 15 years admitted with head injury between July 1966 and June 1981. Data were collected on 1 820 admissions. There were significantly higher percentages of Coloureds and Blacks, males and children aged under 6 years in the sample than in the corresponding population of the Cape Peninsula. In children under 1 year old, fails accounted for approximately 70% of head injuries in all three race groups. In the 1-5-year age group, transport-related injuries were the most common cause of admission in Blacks (63,1%) and Coloureds (46,5%), but in Whites falls were still most common (58,2%). In the 6-14-year age group, transport-related accidents accounted for approximately 64% of head injuries in all three race groups. Pedestrian accidents were the commonest cause of admissions due to transport-related head injury. Severe or very severe concussive injuries, multiple injuries or death occurred more commonly in transport-related injuries than among those caused by falls or assault/abuse. Transport, falls and assault/abuse together accounted for 88,4% of all causes of head injury.
Adolescent↗
Mechanism of action of hydralazine on vascular smooth muscle.
Myofibrils prepared from bovine carotid arteries were used to investigate the hypotensive action of hydralazine. These myofibrils contained an ATPase and Protein Kinase which was half-maximally activated by 1 microM Ca2+. Hydralazine inhibited Ca2+ dependent ATPase and phosphorylation. Half maximal inhibition occurred at 2 X 10(-5) M hydralazine. This inhibition was accounted for by a specific reduction in the phosphorylation of a protein which migrated with the myosin P-light chains (Mr, 20,000). Phosphorylation of the latter protein is generally thought to be obligatory for muscle contraction. Thus an inhibition of this phosphorylation by hydralazine in vivo is likely to contribute to the hypotensive action of the drug.
Actomyosin↗
Polymorphism of alcohol dehydrogenase in Arabidopsis thaliana (L.) Heynh.: genetical and biochemical characterization.
Zymograms of Arabidopsis alcohol dehydrogenase (ADH; EC 1.1.1.1) show a unique anodal migrating band. Three electrophoretic variants were identified among geographical races and designated slow (S), fast (F), and superfast (A), according to their mobility on Tris-citrate starch gels. In plants ADH activity is confined mainly to pollen, seeds, and grains and rapidly declines during the germination process. In callus and suspension cultures, growing on media containing 2,4-D, ADH appeared as one of the major polypeptides. Genetical analysis indicated that the three types of ADH isozymes are under the control of one gene with three alles (Adh1S, Adh1F, Adh1A), showing codominant expression. Crosses between the electrophoretic types and dissociation-reassociation experiments showed that the Arabidopsis enzyme behaves as a dimer, like ADH from most other species. The molecular weight of the enzyme has been estimated by gel filtration and by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis to be 87,000. The pH optimum for the oxidation of ethanol is 9.0 and two optima for reduction of acetaldehyde have been obtained, 6.0 and 8.5, respectively. The enzyme exhibits a wide substrate specificity for alcohols and is relatively heat resistant.
Alcohol Dehydrogenase↗
Single motor-unit control by normal and cerebral-palsied males.
Single motor-unit (SMU) control was compared for three ambulatory cerebral-palsied and three neurologically unimpaired subjects. Both groups were similar in their abilities to produce a discrete whole muscle contraction, to isolate and maintain firing of a single motor unit, and to turn a unit on at a visual signal. Unit inter-spike intervals were very similar for both groups. However, the cerebral-palsied subjects showed a consistent inability to inhibit single motor-unit (or whole muscle) activity if the isolated unit had been firing for some time; normal subjects did not show a similar inability.
Adolescent↗
Glucocorticoids preferentially increase fetal alveolar beta-adrenoreceptors: autoradiographic evidence.
To localize fetal rabbit lung beta-adrenoreceptors before and after glucocorticoid treatment, light microscopic autoradiography was performed with the reversible radiolabeled beta-adrenergic antagonist, [3H]dihydroalprenolol, on day 26 of gestation. Autoradiograms of adult lung and fetal myocardium were also prepared. Examination of these autoradiograms showed densely labeled airways, alveoli, and myocardium. Specific labeling, defined as that prevented by incubation with l-propranolol (1 microM), was 90%. Analysis of grain counts in the fetus showed that airways were more densely labeled than alveoli (p less than 0.001), labeling was increased by treatment (p less than 0.001) and treatment increased alveolar (p less than 0.002) but not airway labeling. Adult lungs were much more densely labeled than fetal, and fetal myocardial labeling was not altered by treatment. Adult untreated lung showed the same pattern as fetal untreated lung with airways being more densely labeled than alveoli (p less than 0.001). To validate estimates of relative beta-adrenoreceptor concentration derived from autoradiograms, comparisons to determinations of beta-receptor concentration from scintillation counting of lung section digests and from previously performed radioligand binding studies, using membranes prepared from whole lung homogenates, were made. There is excellent agreement between estimates of relative receptor concentration and specific binding derived from the counting of autographic grains and both scintillation counting of lung section digests and previously performed radioligand binding of lung particulate. In all preparations, specific binding was (90%), increased with glucocorticoid treatment in fetal lung (50-100%), was greater in concentration in adult compared to fetal lung (7-10-fold), and did not increase in fetal myocardium with treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Drug reservoirs in topical therapy.
The nictitating membrane, corneal epithelium, and corneal stroma were investigated as drug reservoirs. A hydrophilic drug, D,L-epinephrine HCl, or a lipophilic drug, chloramphenicol, was applied topically to rabbit eyes. Tissue levels of radioactive drug-plus-metabolites and unmetabolized epinephrine were assayed up to 24 hrs later. On a per-mg-tissue basis, concentrations of epinephrine-plus-metabolites in the stroma-endothelium were similar to or higher than those in the epithelium. The percentages of radioactivity representing unmetabolized epinephrine in the stroma-endothelium were found to be similar to or higher than those in the epithelium. On a per-mg-tissue basis, concentrations of chloramphenicol-plus-metabolites were significantly higher in the epithelium than in the stroma-endothelium during the first 130 min after drug application. While the physical properties of these drugs determined whether a higher concentration was found in the epithelium or stroma-endothelium, the ninefold greater mass of the stroma-endothelium made it the major drug reservoir on a per-whole-tissue basis. The presence or absence of a nictitating membrane had little effect on the level of either drug in the epithelium, stromal-endothelium, or aqueous humor.
Animals↗
Sustained alterations in lipoprotein cholesterol concentrations dependent on the daily distribution of lipid intake.
Since the fat content of a single meal influences chylomicron size and hence intestinal apoprotein synthesis, we determined the chronic effects of the daily distribution of fat intake on plasma concentrations of total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C). Eight normal male subjects ingested 100 g of fat (a) as a bolus at the evening meal (SL) or (b) equally distributed over 4 meals (q4h) (DL). Each diet was consumed for 7 days; studies were performed 14 days apart using a crossover design and paired comparisons. Nutrient intake and body weight were held constant. At the end of the DL dietary regimen, fasting plasma concentrations of TC, LDL-C and HDL-C were significantly increased as compared to the SL phase of study (TC: 174 +/- 2.9 (mean +/- SEM) vs 161 +/- 2.7; LDL-C: 108 +/- 3.2 vs 98 +/- 3.3 and HDL-C: 53 +/- 1.1 vs 48 +/- 0.8) (P less than 0.05). The consumption of 100 g/day of fat in several small meals results in a sustained increase in LDL-C and HDL-C. This may be due to increased synthesis of lipoprotein components (e.g. apoprotein A-I) or to altered metabolism of intestinal and hepatic TG-rich lipoproteins dependent on size, number and apoprotein composition.
Adult↗
Intermediate filaments in smooth muscle tumours.
Antisera to the intermediate filaments vimentin and desmin react with fixed paraffin embedded tissue. Benign uterine myomas contain both classes of filaments. Gastrointestinal "smooth muscle tumours" however often lack desmin even when they appear histologically benign. In the sarcomas examined vimentin was the only class of intermediate filament present. The diagnostic and histogenetic implications of these findings are discussed.
Adult↗
Internal mammary implantation: the need for revival of a simple technique.
Available statistics on breast cancer indicate a high frequency of positive internal mammary nodes, which is associated with decreased five-year survival rates. The close proximity of the majority of internal mammary nodes (87 percent within 1 cm) to the internal mammary vessels makes them easily accessible to high-dose intravascular continuous irradiation by afterloading radioactive ribbons (iridium 192) in the internal mammary vessels that are surgically exposed. This is a simple technique that can be carried out at the time of mastectomy or as a separate procedure, either as a primary radiation modality, for post-XRT recurrence, or as a boost in combination with conventional parasternal radiation therapy. The step-by-step technique, indications, need for revival, and future implications are presented.
Brachytherapy↗
The organization of 10 nm filaments and microtubules in embryonic neurons from spinal ganglia.
The distribution of tubulin and 10 nm filament protein: vimentin and the 70 K neurofilament component, was investigated in cultures of dorsal root ganglion cells by indirect immunofluorescence using antisera specific for these proteins. The neuronal cell bodies and the neurites in these cultures were brightly stained. Fibres stained with both tubulin and 10 nm filament antibodies were visible at branch points, whereas only microtubules extended into growth cones, including those that were in the process of bifurcation. Differences in the arrangement of microtubules and 10 nm filaments were also detected during colcemid-induced neurite retraction. After complete retraction, perinuclear coils of 10 nm filaments were found in the cell bodies whereas only very weak diffuse tubulin staining was visible. When regrowth commenced on removal of colcemid, microtubule organizing centres were visible in the cell bodies and were then rapidly obscured by bright staining which later extended into the neurite stump. Similarly, the 10 nm coils were replaced by fibrous staining which also projected into the growing neurite. These observations suggest that the extension of microtubules and 10 nm filaments is both co-ordinated and sequential, with microtubules having a dynamic role in growth and 10 nm filaments stabilizing the pattern of growth thereafter.
Animals↗
The ethmoidal "polypoid mucocele".
Seven patients with polypoid mucoceles of the ethmoid sinuses were examined by computed tomography (CT). The findings in all cases were remarkably similar. This unique CT appearance has not been seen with malignancies and should be considered characteristic of this benign entity.
Adolescent↗
Vimentin and 70K neurofilament protein co-exist in embryonic neurones from spinal ganglia.
The mesenchymal intermediate filament protein vimentin and the 70K component of neurofilament were detected by two-dimensional gel electrophoresis in cultures of pure sensory and sympathetic neurones derived from chick embryos. The identities of these neuronal intermediate filament proteins were confirmed by comparison of their molecular weights, isoelectric points, and peptide patterns from limited papain digestions with those of the corresponding proteins from fibroblasts and brain, respectively. A specific antibody to vimentin stained filamentous structures and colcemid-induced coils in both neurones and associated satellite cells. In contrast, a specific antibody to the 70K neurofilament protein stained these structures solely in neurones. This neurone-specific staining, as well as its molecular weight and isoelectric point, distinguishes the 70K neurofilament protein from the 68K neurofilament associated protein described by others, which has been claimed to resemble the tubulin assembly protein.
Animals↗
Histologic monitoring of murine mammary tumor lysis induced by an autologous serum factor.
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Adenocarcinoma↗