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Biomedical subjects

J Weininger

Publications and source records attributed to J Weininger.

30 records · Page 2Linked to original sources
PubMed1982

Comparative cardiac effects of three hepatobiliary radiopharmacologicals in the dog: concise communication.

Three hepatobiliary agents with an acetanilide-imidoacetic-acid moiety resembling that in lidocaine were investigated for their possible effects on contractility and conductivity in the heart and on arterial pressure and aortic blood flow. This was done in the light of lidocaine's numerous cardiac side effects. HIDA, BIDA, and DIPA, each with traces of decayed Tc-99m, were injected i.v. into anesthetized dogs with an A-V block, and their effects on the above parameters were followed until control levels were reestablished. Whereas lidocaine raises the diastolic threshold and prolongs the refractory period, the three agents tested do not prolong myocardial conductivity. Both HIDA and BIDA have an effect similar to that of lidocaine, but DIPA has no effect on the latter two parameters. Moreover, whereas lidocaine depressed myocardial contractility, blood pressure, and blood flow, HIDA has a less prominent effect on these parameters, and neither BIDA nor DIPA has any such effect. It is concluded that even though the effect of HIDA on the heart is milder than that of lidocaine, the effects of both BIDA and DIPA are even less pronounced, and they are less likely to cause cardiac side effects when similar doses are administered during nuclear medicine procedures.

Animals↗
PubMed1978

Tc-99m pyridoxylidene glutamate in jaundiced patients.

Ninety patients, 85 of them jaundiced, were examined after the injection of Tc-99m pyridoxylidene glutamate, a substance rapidly concentrated by normal hepatocytes and excreted into the biliary tract. It appears in the gallbladder after 10-15 min, and in the gastrointestinal tract at 30 min. On the basis of the time of appearance in the intestine, four groups of patients were recognized: 1. Seventeen patients with a normal pattern, with visualization of the gut at 30 min. 2. Nineteen patients with a slight delay in passage, with appearance in the gut between 30-180 min. 3. Twenty-nine patients showing very slow excretion visualized only at 24 hr; 21 of these had parenchymatous disease of the liver, three choledocholithiasis and five had malignant disease causing partial obstruction. 4. Twenty-five patients with no visualization of the intestine; eight of them proved to be cases of medical jaundice, and 17 were surgical cases. Groups 3 and 4 comprise 54 patients where the question of medical or surgical jaundice was critical. If lack of intestinal activity is considered an indicating surgical jaundice, the accuracy of this study was only 72.4%.

Diagnosis, Differential↗
PubMed1975

Quantification of plasma cholesterol and triglyceride levels in hypercholesterolemic subjects receiving ascorbic acid supplements.

In order to assess the possible effects of ascorbic acid on plasma cholesterol and triglyceride levels and plasma lipoprotein composition, nine hypercholesterolemic subjects were treated with oral ascorbic acid (4 g/day) for 2 months. The data demonstrate: 1) no significant change in plasma cholesterol or triglyceride levels; 2) no significant change in the cholesterol or triglyceride concentrations of the major lipoprotein classes; and 3) the unexpected appearance of extra pre-beta bands on lipoprotein electrophoresis by the end of the ascorbic acid treatment period.

Adult↗
PubMedDate not supplied

Paramagnetic enhanced proton magnetic resonance measurement in rats: correlates with renal function.

Renal cortical, medullar and papillary T1 and T2 relaxation times were measured in rats with normal (n = 13) and impaired renal function (n = 11) with a Bruker Multispec, 20 MHz at 37 degrees C. In one group of seven rats, decreased renal function was obtained by 50% glycerol solution administration (10 ml/kg-body weight) 24 hours before the experiment, while in another group of four rats the renal function was decreased, by ureteral ligation for 72 hours. Immediately after the excision of one kidney, Gadolinium-DTPA (70 mumole/kg body weight) was injected intravenously. The second kidney was excised 5 min later. From the T1 and T2 relaxation times measured in the cortex, medulla, and papilla, their respective ratios before and after GdDTPA administration were calculated and correlated with GFR determined by creatinine clearance (Ccr range was between 0 and 850 microliters/min/g kidney weight). For T1: the ratios in the cortex, medulla, and papilla the correlation coefficients were r = 0.81 (p less than 0.001), r = 0.85 (p less than 0.001), and r = 0.87 (p less than 0.0001), respectively. The respective correlation coefficient r values for T2 were r = 0.38 (NS), r = 0.76 (p less than 0.001), and r = 0.73 (p less than 0.001). The present study indicates that a combination of MR measurements, with and without GdDTPA paramagnetic enhancement, can offer a new possibility for obtaining information on renal function and suggest the possibility of concomitant anatomo functional magnetic resonance imaging.

Animals↗
PubMedDate not supplied

Renal proton magnetic resonance in experimental acute renal failure in rats.

Cortical, medullary and papillary T1 and T2 water proton relaxation times were measured at 37 degrees C, 20 MHz. The measurements were made using kidneys from rats affected by many forms of experimental acute renal failure (ARF), namely acute hemorrhagic hypovolemia, angiotensin II administration, antidiuretic hormone (ADH) administration, glycerol, and other nephrotoxins (gentamicin, cisplatinum, cyclosporine), renal artery occlusion for different periods of time, and ureteral ligation. From the T1 and PW (percent tissue water content) the bound water (FB) and HF (percent water bound/g solid) were calculated according to a fast proton diffusion model. In most experimental models studied, the experiments were repeated following paramagnetic enhancement with GdDTPA administration (70 mmol/kg BW). By profiling the deviations from normal, it was possible to differentiate the ischemic (shortened T1, prolonged T2), obstructive (very high T1 and T2 in both cortex and medulla) and nephrotoxic (prolonged T2) forms of ARF. Significant changes in free/bound water compartments occurred, though their biological significance is unknown. T1 and T2 ratios before and after paramagnetic enhancement correlated well with estimates of glomerular filtration rate. In the first minutes following acute hemorrhagic hypovolemia, the intrarenal water distribution remained unchanged. After GdDTPA significant water proton T1 and T2 changes characterized the immediate posthemorrhagic state similar to the effect of ADH.

Acute Kidney Injury↗
PubMedDate not supplied

Renal proton magnetic resonance and bound and free water distribution in the normal, angiotensin II-and ADH-infused rats, before and after Gd DTPA paramagnetic enhancement.

Female Charles River rats, 250-300 g, were used in all experiments. The rats were divided into the following experimental groups. Group A: Normal rats were injected with 1 ml saline intravenously. Exactly after 8 min the kidneys were excised as rapidly as possible. The papilla was dissected and cortical and medullary slices were prepared. Immediately following the excision T1 and T2 were measured with a Bruker PC-20 Minispec spectrometer operating at 20 MHz at 37 + 1 degree C. Water content (PW) of the samples was calculated as a percentage tissue weight, after 24 h drying to constant weight. The fraction bound (FB = % water bound) and hydration fraction (% water bound/g solid) were computed from T1 relaxation time, and the PW, according to a fast proton diffusion model. Group B: As group A but 3 min after the saline administration bolus of 1 ml solution of Gd DTPA. 70 mumol/kg body weight, was given intravenously. Group C: As group A but instead of saline the rats were given a solution of ADH (5 mU/kg body weight i.v.). Group D: As group C plus Gd DTPA as in group B. Group E: As group A but instead of saline the rats were given a solution of angiotensin II (Ag II) (5 micrograms/kg body weight). Group F: As group E plus Gd DTPA as in group B. In groups B-F the magnetic resonance and water distribution were determined and calculated as in group A. In the normal rats there is a prolongation of T1, T2 and an increased total water content from the cortex to the papilla.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗