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Biomedical subjects

G Simon

Publications and source records attributed to G Simon.

At least 325 records · Page 18Linked to original sources
PubMed1977

Cardiopulmonary dimensions: stability over a long period.

The transverse diameter of the heart, diameters of the basal arteries, lung height and width, and diaphragm level were measured from two radiographs obtained 10-34years apart in 100 normal subjects. No difference was found in basal artery diameters, lung height, or diaphragm level. Lung width increased slightly. Transverse diameter of the heart increased slightly (0.43 cm) but significantly. This increase was not related to the age of the subject and had a low linear correlation with the interval between radiographs. In eight subjects, the heart diameter increased by more than 1.5 cm. Age is not an important factor in judging heart size from the transverse diameter on chest radiographs.

Adult↗
PubMed1977

[Comparison of scintigraphic and neurosurgical findings in brain tumors].

In 120 cases of operated brain tumors the neurosurgical findings are compared with the results of brain scintigraphy with 99mTc-pertechnetate. The study comprises only the frequent types of brain tumors such as meningeoma, astrozytoma, glioblastoma, oligodendroglioma, neurinoma and metastases. From the neurosurgical findinds were evaluated the localisation and size of the tumor, the extent of vascularity, of cysts and necroses. These data were related to the type or radioangiography and the degree of uptake in the scintigraphy. The tumors could be demonstrated by scintigraphy in 105 of the cases. Radioangiography was obviously superior to late scintigraphy in the diagnosis of the type of tumor. The size of the tumor appeared in the meningeomas greater and in the other types of tumor smaller than found by operation. The uptake in scintigraphy showed a correlation to vascularity. Otherwise there was found no correlation between vascularity and type of radioangiography in glioblastomas. This surprising result needs further investigatiion. Half of the cases with cysts and necroses showed an inhomogeneity in the uptake by the tumor.

Astrocytoma↗
PubMed1977

Cholinesterase activity in rat liver and serum during experimentally induced inflammation.

Cholinesterase activity of albino rats with acute local oedematous inflammation induced by turpentine, croton oil or Freund's adjuvant was elevated in the liver homogenate but decreased in the serum. Aprotinin administration prevented the decrease of serum activity. In the oedema fluid of rats treated with croton oil an enzyme with cholinester splitting activity was detected and it was shown to be identical with serum cholinesterase (EC 3. 1. 1. 8.).

Animals↗
PubMed1977

Erythrocyte acetylcholinesterase activity is not affected by adenovirus-induced haemagglutination.

No correlation was found between adenovirus-induced haemagglutination and AChE activity of human RBCs as ascertained with three different types of virus. The haemagglutination titre of the adenoviruses did not decrease when RBCs with AChE inhibited by dichlorvos or eserine were used. The receptors involved in active haemagglutination by adenoviruses thus seem to differ from those acting in passive haemagglutination. The AChE inactivating effect of substances such as tannic acid and glutaraldehyde, among others, might be due to a non-specific damage of the RBC membrane.

Acetylcholinesterase↗
PubMed1976

Light scattering from suspensions of membrane fragments derived from sonication of beef heart mitochondria.

The intensity of light scattering from suspensions of membrane fragments prepared by sonication of beef heart mitochondria in the presence of EDTA at alkaline pH (ESMP) was determined at 45, 90, and 135 degrees with light of wavelength 546 nm. The dissymmetry ratio Z = I45 degrees c/I135 degrees c, where I45 degrees c and I135 degrees c are the scattering intensities at 45 and 135 degrees extrapolated to zero particle concentration and corrected for reflectance effects, was used to calculate particle size from the Rayleigh-Gans-Debye theory. An average particle diameter D of 184-190 nm was obtained, within the range of particle diameter 50-300 nm determined previously by electron microscopy. This average diameter determined by light scattering is a useful parameter for characterization of ESMP particle size. We propose the term: light scattering average particle diameter, DLS, for this parameter. The refractive index of ESMP was determined to be 1.443 by measurement of scattering intensity in buffer solutions of varying sucrose concentration. The value of Z was independent of sucrose concentration in this determination, showing that the particles are osmotically inactive toward sucrose. The values of average particle diameter DLS and of refractive index fall within the range of validity of the Rayleigh-Gans-Debye theory, for which light scattering changes are attributable solely to dimension change, rather than to change in particle refractive index. Uptake of water accompanying energy-linked salt uptake in ESMP was calculated from light scattering changes to be 0.18 mul of H2O/mg of protein, compared with 0.49 mul of H2O/mg of protein measured by dextran inaccessibility. Measurement of light scattering changes provides a rapid and sensitive method for determining volume changes of ESMP. The magnitude of the volume change observed during energy-linked water and salt uptake and the initial degree of hydration suggests that ESMP are analogous to polyelectrolyte gels with regard to sorption of strong electrolytes and that the Donnan formulation for ion exchange equilibria may be usefully applied to these processes in ESMP.

Animals↗
PubMed1976

Two radiological observations on chest radiographs of children.

A. The frequency with which a ring shadow of the anterior bronchus could be clearly seen was investigated. The annual radiographs of the same normal children studied in another paper (Simon and Rona, 1976) were examined to see how often a small 3-5 mm ring shadow lying laterally near the upper part of the hilum could be clearly seen. This was the ring shadow most frequently seen and appears to be due to the anterior bronchus seen end on. B. In some children vessel size in the upper lobes is the same as that in the lower lobes. This tends to change to the adult pattern as the child grows older.

Adolescent↗
PubMed1976

Standard of the descending (basal) pulmonary artery in children from the routine chest radiograph.

The right and left basal artery have been measured in serial radiographs taken annually for 3 years or more, in 48 boys and 45 girls, all clinically normal. Centiles were constructed from 5 to 15 year old children. A study of the gain in size revealed a growth spurt during the pubertal period corresponding to that seen with height or weight gain. Correlations were found between right basal artery size (RBA), height and weight. Between 22 and 40% of the RBA diameter can be explained by these two metric traits. Multiple regression equations were therefore constructed to predict the diameter of the artery from a knowledge of the height and weight of the person. It is suggested that these can be of help especially in borderline cases when the size of the basal artery falls between the 90th and 97th centile. A study of 14 patients with a diagnosis of pulmonary hypertension or increased blood flow or both were plotted on one of these charts. In 11 the RBA was above the 97th centile. In three who had high pulmonary artery pressure. the RBA was of normal width and they may well have been near or in the Eisenmenger situation. The limiation in that situation was underlined.

Adolescent↗
PubMed1976

An investigation of the chest radiographs in a controlled trial of busulphan, cyclophosphamide, and a placebo after resection for carcinoma of the lung.

A standard series of radiographs of 588 patients allocated at random to treatment with busulphan (B patients), cyclophosphamide (C patients), or a placebo (P patients) for two years after surgery for bronchial carcinoma were viewed in three stages (following procedures which avoided bias) by an independent assessor, unaware of the allocated treatment of any patient, with a view to identifying pulmonary changes due to busulphan. Radiographic appearances consistent with busulphan lung were not reported in any of the 195 B patients (receiving a mean dosage of 464 mg of busulphan over 301 days) or of the 192 C patients but were present in one of the 201 patients receiving placebo.

Bronchial Neoplasms↗
PubMed1976

Altered venous function in hypertensive rats.

The vascular beds of the upper or lower body of rats were perfused through the aorta with oxygenated Krebs-Ringer solution containing dextran (7 g/100 ml), at 37 degrees C. Perfusion was stopped every 10 minutes, and the pressure rise in the jugular or the femoral vein was recorded during rapid infusion (15.3-90.0 ml/min) of Krebs-Ringer solution into the inferior vena cava. The following groups of rats were studied: (1) six male genetically hypertensive rats (GHR), 9-11 months old, New Zealand strain; (2) seven female GHR, 5-6 months old, New Zealand strain; (3) eight male spontaneously hypertensive rats (SHR), 4 months old, Okamoto strain; (4) five male rats with two-kidney Goldblatt hypertension (2-KGH), 30 days postclipping; (5) seven male 2-KGH rats, 65 days postclipping; (6) eight male rats with one-kidney Goldblatt hypertension (1-KGH), 40 days postclipping; (7) weight- and sex-matched normotensive control rats of the appropriate strain; and (8) weight- and sex-matched two-kidney and one-kidney, sham-clipped normotensive rats. Preliminary studies showed that rapid infusion into the venous circulation fills the veins, but there is no entry of fluid into the arterial side of the circulation. Compared to controls, the venous pressure-volume curves of GHR (male and female), SHR, 1-KGH rats and 2-KGH rats, 65 (but not 30) days postclipping, were shifted toward the pressure axis (P less than 0.05). The shift of the venous pressure-volume curves persisted following the reduction of vasoconstrictor tone by killing the rats or by the administration of sodium nitroprusside (0.1 mg/ml perfusate), or by both. The findings suggest decreased venous capacity in hypertensive rats.

Age Factors↗
PubMed1976

Bioassay in vivo for circulating vasoactive agents after renal artery constriction in dogs.

We used the gracilis muscle vascular bed to bioassay blood from the two renal veins, vena cava, and aorta continuously for the presence of vasoactive agents before and for 45 minutes after partial occlusion of the left renal artery in dogs. Compared to comparable blood samples from control dogs, left renal venous, vena caval, and aortic blood, but not right renal venous blood, from dogs with renal artery constriction developed vasoconstrictor activity. This was associated with increased renin concentration in plasma from the left renal vein and the vena cava and an increase in systemic arterial pressure. In dogs pretreated with indomethacin, blood from the right renal vein also showed vasoconstrictor activity. Pretreatment with antirenin serum abolished all of the differences between control and experimental dogs. These findings suggest that during acute unilateral renal artery constriction the constricted kidney releases renin and the contralateral kidney releases prostaglandins in sufficient quantity to produce systemic vascular effects.

Animals↗
PubMed1976

Decreased venous compliance in dogs with chronic renal hypertension.

Femoral vein (FV) pressure-volume relationships were measured in vitro in 14 dogs with chronic (more than 4 weeks), one-kidney perinephritic hypertension and in 13 unilaterally nephrectomized normotensive control dogs. Segments of FV were also examined histologically and analyzed for their water and electrolyte contents. Compared to controls: (I) the FV pressure-volume curves of hypertensive dogs were shifted toward the pressure axis (P is less than 0.05); (ii) calcaulated vagous compliance in the pressure range of 0-15 mm Hg was decreased (P is less than 0.05); and (iii) the water and sodium contents of vwins from hypertensive dogs were increased (P is less than 0.05). Histological examination of the FV from hypertensive and control dogs did not reveal significant differences. The findings indicate that the decreases in venous compliance that we have previously observed in the early stages (less than 4 weeks) of perinephritic hypertension in dogs persist into the chronic stage of hypertension. Venous wall "edema" may account for the decreased venous compliance in this form of hypertension.

Animals↗
PubMed1975

Mesenteric hemodynamics in early experimental renal hypertension in dogs.

To investigate mesenteric hemodynamics in early perinephritic hypertension, we measured blood flows and intravascular pressures in innvervated, collateral-free, naturally perfused loops of ileum in 50 male mongrel dogs anesthetized with sodium pentobarbital. In addition, we studied venous pressure-volume relationships in temporarily occluded segments of mesenteric veins in vivo and in excised segments of mesenteric veins in vitro. In 10 dogs (group H-1), one kidney was wrapped in silk 11 days before study; in 15 other dogs (group H-2), one kidney was wrapped 4 weeks before study and the other was removed 2 weeks before study. Twenty-five additional dogs were prepared as normotensive controls: in 10 one kidney was sham-wrapped (group C-1), and in 15 one kidney was sham-wrapped and the other was removed (group C-2). A significant rise in mean arterial blood pressure occurred in groups H-1 and H-2. Compared to controls, (1) ileal blood flow in the hypertensive dogs (H-1 plus H-2) was increased by 17% (P smaller than 0.05), (2) calculated ileal vascular resistances (total and segmental) were unchanged (P smaller than 0.05), and (3) in vivo and in vitro mesenteric vein pressure-volume curves of H-2 (but not of H-1) hypertensive dogs were shifted in the direction of the pressure axis (P smaller than 0.05). These data suggest that in the early stages of perinephritic hypertension in dogs (1) ileal blood flow is increased. (2) ileal vascular resistance is not elevated, and (3) mesenteric venous compliance is reduced. Analysis of the venous pressure-volume curves suggests that the decreased venous compliance is attributable to factors other than smooth muscle contraction.

Animals↗
PubMed1975

Diagnosis of emphysema.

Thirty-seven patients with chronic obstructive lung disease (COLD) were divided into three groups on the basis of radiologic evidence of emphysema. The category of radiologic emphysema correlated with severity of abnormality of routine lung function, gas exchange and lung mechanics. Within the group of patients with no radiologic abnormally, a subgroup with severe functional abnormalities, quite similar to those found in patients with widespread radiologic emphysema, could be selected on the basis of maximum elastic recoil less than 10 cm H2O.

Female↗