Influence of dietary cholesterol, saturated and unsaturated lipid on 3-hydroxy-3-methylglutaryl CoA reductase activity in rabbit intestine and liver

To characterize further the behavior of the rate-limiting enzyme of cholesterol biosynthesis in animal species, we studied the kinetic properties and the influence of dietary lipid on intestinal and hepatic HMG-CoA reductase activity in the rabbit. In intestinal crypt and villous cells isolated by a dual buffer technique, the KM value was 4.2 and 4.6 microM, respectively for DL-HMC-CoA. The specific activity of HMG-CoA reductase in the jejunum was 0.86 nmol/mg per hr, and evenly distributed between crypt and villous cells. By contrast, reductase activity was considerably lower in the ileum: in villous cells it was 0.40 nmol/mg per hr, and in crypt cells only 0.26 nmol/mg per hr. Liver microsomes had a KM value of 3.0 microM, while the reductase activity averaged 2 nmol/mg per hr. An unexpected finding was the uneven distribution of HMG-CoA reductase in the various lobes of the liver in the single animal. The addition of 1% cholesterol to the diet for 48 hours was followed by an average decline of 73% (P less than 0.005) of HMG-CoA reductase activity in villous and crypt cells of the jejunum. In the ileum, the decrease was less marked (38%, P less than 0.01). Whereas the addition of 5% corn oil to a 1% cholesterol diet did not have an additional suppressant effect on intestinal reductase, the addition of 5% coconut oil to 1% cholesterol caused further decrease of HMG-CoA reductase in jejunum and ileum (P less than 0.05). The 1% cholesterol diet resulted in a 25% decrease of hepatic reductase after 24 hours, whereas after 6 days, the enzyme activity was reduced by 90% of normal. Both 5% corn oil or 5% coconut oil, in addition to 1% cholesterol, further suppressed hepatic reductase activity. The weight of the experimental evidence presented in these studies suggests that cholesterol has a major regulatory effect on both intestinal and hepatic reductase in the rabbit.

Lipoprotein regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase in cultured intestinal mucosa

In vitro regulation of the key enzyme of cholesterol synthesis, 3-hydroxy-3-methylglutaryl-CoA reductase (EC 1.1.1.34), was studied in 24-h organ culture of rabbit ileum. Preincubation of mucosal homogenate in phosphate buffer increased apparent reductase activity more than 5-fold. The activation was blocked in the presence of 150 mM NaF, suggesting interconversion of latent reductase by dephosphorylation. No significant further activation was achieved by potato phosphatase treatment. During culture total reductase activity was stimulated by 125% in lipoprotein-free medium. Addition of low density lipoprotein to the medium resulted in a dose-dependent suppression of reductase activity between 0.2 and 1.0 mM lipoprotein cholesterol. At these concentrations LDL inhibition reached 51 and 75% of control, respectively. The reductase response to very low density and high density lipoproteins was biphasic, with a 2- to 3-fold stimulation at 0.1-0.3 mM and a suppression at higher levels. No such stimulation was observed with high density lipoproteins obtained from cholesterol fed animals. Similarly, 'hypercholesterolemic' very low density lipoproteins enhanced reductase activity only slightly. It is concluded that lipoproteins are potent regulators of cholesterol synthesis in cultured intestine.

[Problems of choledochoduodenostomy (author's transl)]

Choledochoduodenostomy was performed in 101 cases. In 74 cases the underlying disease was benign choledochus or papilla; in 6 cases, carcinoma of the choledochus; in 19 cases, tumors of the pancreas, and in 2 cases, gastric carcinomas. Postoperative mortality was 8.9% in the malignant and 2.7% in the benign cases. The average age was 72 years. Marked icterus was present in morethan 60%.

[Diagnosis of appendicitis: only experience helps]

Acute appendicitis is a very rare disease in children under 1 resp. 5 years of age. In a series of 1456 cases 8.9% of patients were older than 60 years. In both extreme age groups however perforating appendicitis is a common complication: 40% resp. 37% against 6 to 7% in patients between 5 and 60 years of age. In our series of 1456 cases the correct diagnosis of acute appendicitis was missed preoperatively in 11%. The well described clinical signs and the dates of history vary so widely that they do not guarantee the correct diagnosis. In our opinion clinical experience is the most helpful item in proving the diagnosis of acute appendicitis which ought to be operated upon.

Separation and purification of a potent bactericidal/permeability-increasing protein and a closely associated phospholipase A2 from rabbit polymorphonuclear leukocytes. Observations on their relationship

Two antibacterial proteins from rabbit polymorphonuclear leukocytes, a potent bactericidal cationic protein that increases the envelope permeability of susceptible gram-negative bacteria and a phospholipase A2, have been purified to near homogeneity by ion exchange, gel filtration, and hydrophobic interaction chromatography. The apparently noncatalytic bactericidal/permeability-increasing protein has an approximate molecular weight of 50,000 and is isoelectric at pH 9.5 to 10.0. The molecular properties, including amino acid composition, and the antibacterial potency and specificity of this rabbit leukocyte protein and of the bactericidal/permeability-increasing protein from human granulocytes that we have recently purified (J. Biol. Chem. 253, 2664-2672, 1978) are closely similar. Both proteins kill several strains of Escherichia coli and Salmonella typhimurium. Rough strains are more sensitive than smooth strains. All gram-positive bacterial species tested are insensitive to high concentrations of either rabbit or human protein. The phospholipase A2, purified by hydrophobic interaction chromatography on phenyl-Sepharose, ran as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an apparent molecular weight of 14,000 and had a specific enzymatic activity comparable to that of purified phospholipases A2 from other sources. Separation of the phospholipase A2 from the bactericidal/permeability-increasing protein has no noticeable effect on the bactericidal and permeability-increasing activities of the purified bactericidal protein, but removes the ability of the phospholipase A2 to hydrolyze the phospholipids of intact Escherichia coli. Upon recombination of the phospholipase A2 with the bactericidal/permeability-increasing protein, the phospholipase A2 regains its activity toward the phospholipids of intact E. coli suggesting that these two antibacterial leukocyte proteins act in concert.

Does history-taking affect learning of attitudes?

QUESTION

How can medical students adopt a patient-oriented approach?

SETTING

During the past 7 years approximately 60 preclinical and clinical students joined dynamically oriented group sessions on medical history-taking. An open-ended question technique was used.

EVALUATION

The student's expectations of the patient were monitored by the repertory grid technique using a self-developed dyad grid form which allowed the estimation of reciprocal expectations as seen by the student. A main component analysis of the ratings obtained was performed.

RESULTS

The development in one group was taken as representative of the general development in the different groups. Two main components (MC I, II) were found to account for approximately 40 and 25% of the total variance (distance/empathy and dominance/dependence). The student's main concern is centered on the problem of dependence, MC II. He expects the patient to cling to him. Similarly he feels dependent on the psychosomatic lecturer. He feels as though he is the lecturer's patient. During group work the patient is seen to be less clinging. The student learns that he is not his lecturer's patient but his junior partner. He changes his professional ego-ideal as a future doctor. This is modelled according to his own relationship with the lecturer. It is not modelled according to the usual doctor-patient relationship as perceived by the student. The main characteristic of the change is a lessening of dependency needs as felt in the relationship to the patient.

INTERPRETATION

The findings are interpreted as an attitudinal change in favour of a more patient-oriented attitude. The change was affected through confrontation with the patient's needs. Conclusions were drawn: The student has to be trained how to cope with dependency needs. Special learning settings have to be provided which are staffed with patient-oriented physicians.

Alkalimetric microassay of cephalosporins

Alkalimetric pH-stat titrations of cephalosporin C, cephacetril and their deacetyl derivatives using an acetyl esterase and beta-lactamase are described. The esterase was used to assay highly purified samples of cephalosporin C and cephacetril, and also to prepare analytically defined solutions of the deacetyl cephalosporins. Lactamase-catalyzed hydrolysis of the parent compounds was then found to generate exactly 2 equivalents of acid per mole; that of the deacetyl derivatives exactly 1 equivalent.

Adaptation of a single injection clearance method to physiological and pathophysiological facts. A review of data obtained in infancy and childhood

A retrospective analysis of 395 51Chromiumethylenediaminotetraacetate single injection clearances performed in infants and children is presented. In 61% of infants and 30% of the children the clearance values were calculated on the basis of a plasma disappearance half time of the reference substance, which was longer than the standard study, i.e. on the basis of extrapolated data. Plasma creatinine and urea levels were found to be appropriate indicators for predicting the plasma disappearance half time of the marker substance. 14 additional patients were studied prospectively with a duration of the study predicted by means of the plasma creatinine and urea levels. In these patients, separate determinations of the clearances using either the data obtained during the standard time of procedure only, or the data of the entire study, clearly demonstrated that the clearances obtained by means of the standard procedure overestimated glomerular filtration rate. The analysis of the data in infants show that the plasma urea level is a reasonably good indicator for predicting the time schedule of the study whereas plasma creatinine should not be used. Additionally the retrospective data indicate that a prolongation of the study should be recommended in all infants. This study demonstrates the necessity and offers means of adapting the time schedule of isotope single injection clearances to physiological and pathophysiological facts.

[Scintigraphy of the myocardium. Comparative study between thallium and perfusion scintigrams (author's transl)]

In a total of 51 patients (26 with coronary heart diseases, 25 with primary myocardial diseases), the myocardial scintigrams after intracoronary particle injection (perfusion scintigraphy) and after intravenous nuclide injection with accumulation in the myocardium (thallium scintigraphy) were compared with each other and set against the coronary angiographic and levocardiographic findings. It was shown that extensive myocardial failures (aneurysms) can be represented by both nuclear medical procedures, but that perfusion scintigraphy is more sensitive and correlates more closely to the levocardiogram findings. Smaller abnormalities of contraction of the left ventricle (hypokinetic and akinetic areas) were always shown in the perfusion scintigram, more seldom in the thallium scintigram. The outstanding advantage of thallium scintigraphy is that it is non-invasive, it can be repeated as often as desired and is easily performed during ergometric stress.

[The value of the dynamic dehydroepiandrosterone-test compared to the static measurement of total urinary estrogen excretion in the diagnosis of the condition of the feto-placental-unit (author's transl)]

In a comparative study in 84 pregnant women the condition of the feto-placental-unit was examined through the utilization of the DHEA-test and by the measurement of total urinary estrogen excretion. The test consists of intravenous injection of 50 mg DHEA-S to the mother and measurement of the total estrogen increase during the following 24 hour period as compared to the values before injection. When the condition of the feto-placentalunit is good an increase of estrogens is seen as a consequence of the transformation of DHEA to estrogens by the placenta. The difference between total urinary estrogen excretion before and after the injection of DHEA is considered as a measure of placental function. The results of estrogen determinations and the DHEA test were correlated to placental histology, cardiotocogram, colour of the amniotic fluid, Apgar-score, stillbirth, birthweight, and transfer of newborns to pediatry. We found that in cases with normal estrogen values and especially in cases with a good increase of estrogen excretion following DHEA-S-load there was a high probability of there being no acute risk for the fetus. The DHEA-test has a higher prognostic value than the analysis of urinary estrogen excretion alone, because it is better able to predict pathological findings of the reference parameters cited above. Possible reasons for an insufficient increase of estrogens in the DHEA-test without clinical pathology are discussed. When only a short time remains before birth, a better accord between test-results and clinical findings can be observed. This suggests a weekly repetition of the test.

Thyroid scintigram. Sensitivity with sodium pertechnetate Tc 99m and gamma camera with pinhole collimator

To evaluate the reliability of thyroid scintigraphy in the diagnosis of nodular growth, scintigrams of patients who later underwent thyroidectomy were reviewed and correlated with pathologic findings. The scintigrams were all obtained with a 5-mm single-hole collimator-equipped gamma-scintillation camera after intravenous injection of 5 millicuries of sodium pertechnetate Tc 99m. In the group of 92 patients, six of whom had two histologically different lesions, 149 nodules were identified pathologically. There were 26 nodules 2 to 5 mm in diameter, of which 22 were benign and four were malignant. None of the 22 benign nodules were delineated scintigraphically. Superior image quality and resolution, low radiation dose, technical simplicity, and speed make 99mTc pinhole-camera scintigraphy the best procedure available for routine thyroid imaging.

99mTc-pertechnetate thyroid scintigraphy in patients predisposed to thyroid neoplasms by prior radiotherapy to the head and neck

Histories, physical examinations and 99mTc-pertechnetate imaging were used to evaluate 1,452 persons who had had x-ray therapy to the neck region for benign conditions 18 to 35 years previously. Thyroid abnormalities were found in 301 patients (21%) and thyroid malignancy was found in 29% of 193 patients with abnormal studies who were explored surgically. Thyroid imaging detected 96% of these abnormalities, 40% of which would not have been unequivocally established by physical examination alone. Nuclear imaging could not distinguish benign from malignant lesions.

-Crystallin. The isolation and characterization of distinct macromolecular fractions

alpha-Crystallin was isolated from calf lens periphery by chromatography on DEAE-cellulose and gel filtration. Three distinct populations of macromolecules have been isolated with molecular weights in the ranges approx. 6x10(5)-9x10(5), 0.9x10(6)-4x10(6) and greater than 10x10(6). The concentration of macromolecules at the molecular-weight limits of a population are very low. The members of the different populations do not appear to be in equilibrium with each other. Further, in those molecular-weight fractions investigated, no equilibrium between members of the same population was observed. The population of lowest molecular weight comprises 65-75% of the total material. The amino acid and subunit composition of the different-sized fractions appear very similar, if not identical. The only chemical difference observed between the fractions is the presence of significant amounts of sugar in the higher-molecular-weight fractions. Subunit molecular weights of approx. 19.5x10(3) and 22.5x10(3) were observed for all alpha-crystallin fractions.