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Biomedical subjects

J Simon

Publications and source records attributed to J Simon.

At least 469 records · Page 26Linked to original sources
PubMed1986

153Sm radiotherapeutic bone agents.

Samarium-153 is a radionuclide which can be produced in high yield by neutron irradiation and which has nuclear properties that make it attractive for use as a radiotherapeutic agent. Several phosphonate complexes of 153Sm were synthesized and characterized by electrophoresis and HPLC. A procedure based on cation exchange chromatography was developed for measuring complex yields. The complexes could be produced in yields greater than 99%, were anionic, and most exhibited a single HPLC peak.

Acetates↗
PubMed1986

In vivo skeletal localization properties of 99mTc complexes of large phosphonate ligands.

Tetramethylenephosphonate derivatives of norborane (TPNB) and dicyclopentadiene (TPDCPD) were shown to readily form stable chelates with 99mTc that had high and selective bone uptake. The skeletal uptake and blood clearance properties of 99mTc-TPNB were similar to 99mTc-MDP in both rats and rabbits. This suggests additional studies to further evaluate 99mTc-TPNB or perhaps other large-organic based multidentate phosphonate ligands as potential bone imaging agents is warranted.

Animals↗
PubMed1986

GH3 pituitary adenoma cells can reverse thymic aging in rats.

Thymic size and T-cell function decrease with age, and it has not yet been possible to totally reverse this thymic atrophy and completely restore T-cell-dependent immune functions. In this study, GH3 pituitary adenoma cells, which secrete growth hormone and prolactin, were implanted subcutaneously into 16- and 22-month-old female Wistar-Furth rats and the rats were sacrificed approximately 2 months later. Only thymic remnants were detected in aged, non-implanted rats, but thymus glands were found in both the 18- and the 24-month-old rats that had been implanted with GH3 cells. Thymus glands from the GH3-implanted 18-month-old rats contained distinct cortical thymocytes and medullary epithelial cells. Depending on the concentration of phytohemagglutinin or concanavalin A, T-cell proliferative responses of splenocytes from these implanted rats were 2- to 5-fold greater than those of 18-month-old controls. At the optimal concentration of mitogen, proliferative responses to either lectin could be restored to those levels observed in splenocytes from 3-month-old Wistar-Furth females. Thymus glands from 24-month-old GH3-implanted rats contained more cortical thymocytes and fewer fat vacuoles than controls, but they were not totally reconstituted. No significant lectin-induced T-cell proliferative responses or IL-2 secretion were detected in 24-month-old control rats, but splenocytes from GH3-implanted rats showed augmented T-cell proliferative responses and increased synthesis of IL-2. Fluorescence-activated cell-sorter analysis of thymocytes revealed that 24-month-old rats implanted with GH3 cells had a higher proportion of lymphocytes with the Thy-1.1 and helper-T-cell phenotypes. These data show that it is possible to regenerate normal thymic tissue in situ and reverse the natural loss in cell-mediated immunity that occurs with aging.

Adenoma↗
PubMed1986

Tissue-type plasminogen activator in breast cancer: relationship with estradiol and progesterone receptors.

Plasminogen activator (PA) is an estradiol-inducible enzyme and therefore a potential marker for a functional estradiol receptor (ER) in human breast carcinomas. In this investigation tissue-type PA (t-PA) correlated significantly with both ER and progesterone receptors (PR) in human breast carcinomas. In contrast, neither total PA activity nor urokinase-like PA showed any significant correlation with either ER or PR. Other proteases such as a trypsin-like protease, a chymotrypsin-like protease, and cathepsin B also showed no correlation with ER and PR. It was concluded that the t-PA form of PA may be a marker for a functional ER in breast carcinoma and thus be of value in predicting hormone-dependent breast cancers.

Breast Neoplasms↗
PubMed1986

Utility of caudal view in pelvic bone imaging.

Bone imaging of the lower pelvis often is impaired by the radioactivity of the bladder. The caudal view produces an image that clearly distinguishes the bladder from the bones. Thus, it is helpful in patients with bony lesions of the lower and anterior pelvis. The caudal view examination is completed by a backward tilting of the camera head that clarifies this distinction.

False Negative Reactions↗
PubMed1986

Kinetics and physical parameters of rat brain opioid receptors solubilized by digitonin and CHAPS.

Rat brain opioid receptors were solubilized with digitonin and a zwitterionic detergent, 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS). The yield of solubilization was 70-75% with digitonin and 30-35% with CHAPS. Kinetic and equilibrium studies performed from digitonin extracts resulted in KD values comparable with those of the membrane fractions. Two [3H]naloxone binding sites were obtained in the extracts similarly to membrane fractions. The rank order potency of drugs used in the competition experiments did not change during solubilization. The distributions of mu, delta, and kappa opioid receptor binding sites were similar in membrane and digitonin-solubilized fractions (48-50% mu, 35-37% kappa, and 13-17% delta subtypes). The hydrodynamic properties of digitonin- and CHAPS-solubilized preparations were studied by sucrose density gradient centrifugation and Sepharose-6B chromatography. In all cases, two receptor populations were identified with the following parameters: sedimentation coefficients for the digitonin extracts were 9.2S and 13.2S and for CHAPS extract 8S and 15.6S; the Stokes radii were 45 A and 65A for the digitonin extract and 31A and 76A for the CHAPS-solubilized preparation.

Animals↗
PubMed1986

Plasma lactate and ventilation thresholds in trained and untrained cyclists.

Six trained male cyclists and six untrained sedentary men were studied to determine whether the plasma lactate threshold (PLT) and ventilation threshold (VT) occur at the same work rate in both fit and unfit populations. The PLT was determined from a marked increase in plasma lactate concentration ([La]) and VT from a nonlinear increase in expired minute ventilation (VE) during incremental leg-cycling tests; work rate was increased 30 W every 2 min until volitional exhaustion. The trained subjects' mean VO2 max (63.8 ml O2 X kg-1 X min-1) and VT (65.8% VO2 max) were significantly higher (P less than 0.05) than the untrained subjects' mean VO2max (35.5 ml O2 X kg-1 X min-1) and VT (51.4% VO2 max). The trained subjects' mean PLT (68.8% VO2 max) and VT did not differ significantly, but the untrained subjects' mean PLT (61.6% VO2 max) was significantly higher than their VT. The trained subjects' mean peak [La] (10.5 mmol X l-1) did not differ significantly from the untrained subjects' mean peak [La] (11.5 mmol X l-1). However, the time of appearance of the peak [La] during passive recovery was inversely related to VO2 max. These results suggest that variance in lactate diffusion and/or removal processes between the trained and untrained subjects may account in part for the different relationships between the VT and PLT in each population.

Adult↗
PubMed1986

Further characterization of insulin secretion from the perfused duodenum-pancreas of chicken: a comparison of insulin release in chickens selected for high and low abdominal fat content.

Insulin release from the perfused pancreas was studied in genetically selected fat and lean chickens. The previously described glucose insensitivity of the chicken pancreas cannot be overcome by 5 or 10 mM D-glyceraldehyde, suggesting that the resistance is not related to glucose metabolism before the triose phosphate step. At 42 mM, glucose induced a biphasic insulin release which was specific, since 42 mM mannitol did not elicit insulin release. Arginine (10 mM) or acetylcholine (0.1-1 microM), which in themselves do not cause insulin release, generated a biphasic insulin release in the presence of a low nonstimulating glucose concentration (14 mM); the effect was synergistic. In contrast to the glucose tolerance test observed in vivo, the pancreas from the fat line chicken in response to glucose or glucose plus arginine released significantly less insulin during the first phase. The significance of this defect awaits further elucidation. On the other hand, acetylcholine, a more potent secretagogue, did not reveal any significant difference between fat and lean chickens.

Acetylcholine↗
PubMed1986

Occupation and education in relation to risk factors of ischaemic heart disease in the male industrial population.

In a sample of 3,757 men aged 40-50 years, all employees of a large industrial plant, the authors studied the prevalence of several risk factors (RF) of ischaemic heart disease (IHD) in relationship to profession and education of probands. Blue collar workers were more frequently heavy smokers and regular alcohol consumers than white collars. Compared with other workmen professions a tendency towards a higher risk profile was present in employees doing strenuous manual work. These were heavier smokers, had higher blood pressure and serum cholesterol. Within white-collar professions a higher risk profile was observed in managers with high responsibility than in personnel of the research and development departments. The former were heavier smokers, had higher serum cholesterol and greater overweight. The education level was in indirect association with smoking, hypertension and obesity but correlated directly with regular alcohol consumption. Socio-economic factors evidently influence the prevalence of risk factors of IHD also in the Czech industrial population.

Adult↗
PubMed1985

Separation of kappa-opioid receptor subtype from frog brain.

Complete separation of the [3H]ethylketocyclazocine [( 3H]EKC) specific binding (kappa subtype) from tritiated Tyr-D-Ala2-Me-Phe4-Gly-ol5 enkephalin (DAGO) and Tyr-D-Ala2-L-Leu5-enkephalin (DALA) binding (mu-and delta-subtypes, respectively) was achieved by Sepharose-6B chromatography and sucrose density gradient centrifugation of digitonin solubilized frog brain membranes. The apparent sedimentation coefficient (s20.w) for the kappa receptor-detergent complex was 13.1 S and the corresponding Stokes radius 64 A. The isolated fractions exhibited high affinity for EKC and bremazocine, whereas mu- and delta-specific ligands were unable to compete for the [3H]EKC binding sites, indicating that the kappa subtype represents a separate molecular to compete for the [3H]EKC binding sites, indicating that the kappa subtype represents a separate molecular entity from the mu and delta receptor sites.

Animals↗
PubMed1985

The changing epidemiology of diverticular disease in Israel.

In a retrospective evaluation of 1244 consecutive barium enemas performed at two hospitals over a five-year period (1979 to 1984), colonic diverticula were found in 177 (14.2 percent). The prevalence among the Ashkenazi Jews was 19.7 percent, among the Sephardi and Oriental Jews, 16 percent, and among the Arabs, 9.5 percent. Comparing these figures with the results of a similar study performed ten years ago, it becomes obvious that the prevalence of diverticular disease in the Ashkenazi group remained the same, while there was a three-fold increase among Sephardi and Oriental Jews, and a seven-fold increase among Arabs. It is postulated that, in less than one generation, diverticular disease will be equally frequent among all ethnic groups in Israel.

Adolescent↗
PubMed1985

Lithiasic complications of renal transplantation: the donor graft lithiasis concept.

Lithiasis is usually a late complication of renal transplantation reported in approximately 1% of all renal allografts. Underlying predisposing conditions for the formation of calculi are present in almost all cases. Preexisting stones in the donor kidney have been reported once previously. The authors have observed 2 such cases, detected by routine sonography. In 1 case, stone migration into the ureter led to acute postoperative transplant failure; this complication has been reported previously.

Adult↗