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J Jacobsen

Publications and source records attributed to J Jacobsen.

At least 109 records · Page 6Linked to original sources
PubMed1986

Inhibition of the enzymatic reaction of renin in aggressive mice.

Aggressive behaviour provokes a very high increase in plasma renin in aggressive male mice. We demonstrate that this occurs in mice with high as well as low concentrations of renin in the submaxillary glands, although the highest values were seen in the former. Plasma renin and angiotensinogen concentrations, as well as plasma renin activity, were measured before and after aggression. The theoretical plasma renin activity (generation rate of angiotensin l) was calculated from kinetic parameters and the renin and angiotensinogen concentrations. The Km (Michaelis constant) was 3 mumol/l and the kcat (turnover number) was 0.15/s for the reaction between pure submaxillary mouse renin and mouse angiotensinogen. The measured plasma renin activity was much lower than that calculated from both the kinetics and the fall in angiotensinogen concentration. The decrease in angiotensinogen in vivo was independent of the renin concentration. Intraperitoneally injected renin mimicked the aggression-provoked renin increase and resulted in better agreement between measured and calculated parameters. This indicates, that during aggression, the mouse can inhibit and control the renin-angiotensinogen reaction.

Aggression↗
PubMed1986

Bradycardia during hypotension following release of a tourniquet in orthopaedic surgery.

Heart rate (HR) and mean arterial blood pressure (MBP) were followed in 39 consecutive patients during orthopaedic surgery with the leg exsanguinated by an inflatable tourniquet around the thigh. The circulation was stable in all patients until release of the tourniquet. Following release of the tourniquet MBP decreased from 94 +/- 5 (s.e. mean) to 45 +/- 12 mmHg (12.5 +/- 0.7 to 6.0 +/- 1.6 kPa) (P less than 0.005) in 10 patients, while it remained stable in the others. At the same time the hypotensive group showed a decrease in HR from 83 +/- 6 to 67 +/- 3 beats min-1 (P less than 0.005) while no significant change in HR was seen in the normotensive group. The hypotensive group was older (57 +/- 8 versus 50 +/- 4 years (P less than 0.05)), had a larger blood loss during surgery (2.9 +/- 1.2 versus 0.7 +/- 0.3 ml kg-1 (P less than 0.005)), and the duration of the operation was longer in this group (120 +/- 14 versus 60 +/- 27 min (P less than 0.001). It is suggested that the characteristic deviation of HR in conjunction with hypotension following release of a tourniquet is bradycardia.

Anesthesia, General↗
PubMed1986

Prevalence of anxiety disorders in patients with mitral valve prolapse.

Most previous research on mitral valve prolapse investigated its prevalence in patients whose primary diagnosis was one of the anxiety disorders. This study explored the inverse, i.e., the prevalence of anxiety disorders in patients manifesting mitral valve prolapse. There were no significant differences between patients (N = 48) and control subjects (N = 49) in panic disorder, phobic disorder, or generalized anxiety disorder or in the Zung depression score. The patient group scored significantly higher than control subjects on the Zung Anxiety Scale but significantly lower than Zung's patients with "anxiety neurosis". These results cast doubt on the hypothesis that mitral valve prolapse is etiologically related to the pathogenesis of the anxiety disorders.

Adolescent↗
PubMed1985

Characterization of angiotensin I, II, and III from mouse as position-5 isoleucine [Ile5] angiotensins. An HPLC Study.

Angiotensin I was generated in vitro in mouse plasma by addition of mouse submaxillary renin. After deproteinization on Dowex 50W-X2 ion exchange resin, the samples were separated by reverse phase liquid chromatography and the fractions analysed by radio-immunoassay for angiotensin I. Angiotensin I from mouse was injected into the jugular vein of a nephrectomized rat in order to generate angiotensin II and III of mouse origin. Carotid arterial blood was collected immediately, centrifuged and the plasma deproteinized and separated on high pressure liquid chromatography (HPLC). The fractions were analysed for angiotensin I, II and III by radioimmunoassays. Retention times for mouse angiotensins in the liquid chromatography system were compared to synthetic [Val5] and [Ile5] angiotensin I, II and III. All three mouse angiotensins coincided with the corresponding synthetic [Ile5] angiotensins during elution, suggesting the same type of angiotensin in mouse and man. An additional study on rat angiotensins confirmed previous findings by other investigators, indicating that the angiotensins of this animal were also of the [Ile5] type.

Angiotensin I↗
PubMed1984

Characterization of inactive renin in mouse amniotic fluid.

We have demonstrated high concentrations of inactive renin in mouse amniotic fluid compared with mouse plasma and other organs. Its molecular weight was similar to that of prorenin from the mouse submaxillary gland (42 000 daltons). The activated renin had a Km value of 1.48 greater than M which is identical to that of active amniotic fluid mouse renin. The time course and concentration dependence of trypsin activation was studied, and compared with activation by direct acidification and acidification by dialysis. The pH optimum for acid activation varied with temperature between pH 3 and 4, probably because of simultaneous activation and degradation. Acid activation was almost completely reversible.

Amniotic Fluid↗
PubMed1984

The enzymatic renin reaction in vivo is inhibited in mice during inter-male aggressiveness.

In aggressive male mice with very high plasma renin concentrations the plasma angiotensin II (ANG II) and III (ANG III) concentrations were measured in single mice in order to study whether this renin was active in vivo. The angiotensins were purified and identified by ion-exchange chromatography and High Pressure Liquid Chromatography (HPLC) and quantitated by a specific and sensitive radioimmunoassay. Plasma ANG II and ANG III values were not elevated in aggressive mice compared to normals, in spite of the fact that the plasma renin concentration was increased up to 100 fold and almost equal to the plasma renin-substrate concentration. This indicates an inhibition of the enzymatic renin reaction in vivo during aggression, which is in accordance with the lack of blood pressure increase, and an unchanged pressure sensitivity to ANG II.

Aggression↗
PubMed1983

Albumin-bilirubin binding mechanism.

After binding of bilirubin to human serum albumin (1:1), a train of relaxational changes of conformation takes place. The late part of these processes, occurring in the time interval 1-500 s, has been studied by recording the changes of light absorption. Similar processes have been demonstrated after binding of fatty acid anion to the bilirubin-albumin complex as well as after a pH-jump from 6 to 9. Solvent perturbation spectra obtained on the addition of 20% sucrose have failed to demonstrate exposure of the bilirubin chromophores in the complex to the surrounding medium. Xanthobilirubinate which has a single dipyrrolic chromophore compared to the two of bilirubin is bound to albumin in competition with bilirubin, as concluded from co-binding studies with monoacetyldiaminodiphenylsulfone and diazepam, probing two different binding functions of the albumin molecule. Late conformational changes were absent after binding of xanthobilirubinate. Binding of fatty acid to the complex and a pH-jump did not affect the spectrum of xanthobilirubinate-human serum albumin. The findings can be explained by a model, previously proposed, in which the late spectral changes are affected by rotation of one half-domain of albumin, binding one bilirubin chromophore, relative to another half-domain to which the second bilirubin chromophore is bound, whereby a change of exiton splitting occurs. Such changes are not seen with the complex of xanthobilirubinate and albumin, since only a single chromophore is present.

Bilirubin↗
PubMed1983

Susceptibility to mecillinam and other antibiotics and serogroups of enterotoxigenic Escherichia coli from children in Addis Ababa.

The in-vitro susceptibility of 64 strains of enterotoxigenic Escherichia coli (ETEC) was determined for eight antimicrobial agents. The strains were of 27 different O-serogroups of which 078 was the most common. All strains were susceptible to mecillinam, cefoxitin, gentamicin, and trimethoprim-sulphamethoxazole. Two strains were resistant to ampicillin, 15 to doxycycline, 5 to cephalothin, and 13 to chloramphenicol. No difference was found in the antibiotic susceptibility of ETEC strains producing only heat-labile enterotoxin compared with those producing both heat-labile and heat-stable enterotoxin.

Amdinocillin↗
PubMed1983

The biochemistry of aggression-provoked renin.

The biochemistry of the renin-angiotensin system in aggressive mice may question a simple role of the system in blood pressure regulation. When male mice are fighting, their plasma concentration of active renin may rise several hundred fold without affecting blood pressure. The source of this renin is secretion to the blood from the submaxillary gland and the kidneys, but also small salivary glands may contribute. A further source may be salivary renin transferred by bites from one animal to another, as indicated by recent experiments. The renin concentration in saliva of an aggressor during a fight reaches values of 6000 GU/ml (15 mg/ml). The huge increase in plasma renin is caused by fully enzymatic active 40 000 Mw renin. Preliminary data, collected in order to study whether this renin is active also in vivo, show the following: Inactive renin is present in a small invariable concentration. The renin substrate is consumed in vivo and the measured generation rate of angiotensin is that expected from the renin and substrate concentration. The data seem to indicate that the high concentration of aggression-provoked renin is active in vivo. It is unknown how the mouse protects its blood pressure against this hyperactive pressor system.

Aggression↗
PubMed1983

Renin precursors.

Explore the source record for details and available documents.

Amino Acid Sequence↗
PubMed1983

Wegener's granulomatosis in a child.

A post-mortem diagnosis of Wegener's granulomatosis (WG) was made on a ten-year-old girl. The patient had presented with recurrent sinusitis, progressive proteinuria, and reduced renal function. Biopsies from maxillary sinuses had revealed non-specific chronic inflammation, and a renal biopsy extracapillary glomerulonephritis. Chest X-ray had shown a cavitating nodule in the right lung, initially interpreted as tuberculosis. Lung biopsy had not been performed. To achieve a precise diagnosis in cases with symptoms suggesting WG, open lung biopsy, and abundant biopsy specimens from involved organs are advocated.

Child↗
PubMed1981

Kinetics of neutral transition of human serum albumin.

The fast step in the conformational change of human serum albumin from the alkaline to the neutral form of the albumin-bilirubin complex is studied by various pH jump experiments in a stopped-flow apparatus. The results indicate that the first step is caused by electrostatic attraction between a carboxylate group of bilirubin and a histidine residue of albumin.

Bilirubin↗
PubMed1981

Growth inhibitory effect of mouse serum on eukaryotic cells in a micro assay.

Inhibition of cell growth by B6D2F1 (C57Bl/6 X DBA/2) mouse serum in tissue culture wells confirming previous findings in the soft agar tumour colony assay is reported. The assay was time saving, more sensitive, and the amount of mouse serum used could in each experiment be reduced by 95%. In addition non-neoplastic cells ordinarily not forming colonies in the soft agar assay could be tested. Such cells were less sensitive to the growth inhibitory effect when compared to neoplastic cells.

Animals↗
PubMed1981

A retrospective study of canine hemangiosarcoma and its association with acanthocytosis.

A retrospective study was conducted on cases of canine hemangiosarcoma diagnosed at the Western College of Veterinary Medicine between 1969 and 1979. A total of 33 dogs were assessed with respect to breed, age, sex and site of neoplasia. Hemangiosarcoma was most common in older dogs and there was no sex predilection. Incidence was highest in German Shepherds. The primary sites in order of most frequent occurrence were spleen, right atrium and liver. Acanthocytes were found in six of 12 dogs examined. There was no association between acanthocytosis and such factors as breed, primary site of the neoplasm and splenic or hepatic involvement.

Acanthocytes↗