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Biomedical subjects

A Frenkel

Publications and source records attributed to A Frenkel.

At least 37 records · Page 2Linked to original sources
PubMed1994

SPECT quantitation of cobalt-57-bleomycin to predict treatment response and outcome of patients with lung cancer.

UNLABELLED: Our hypothesis is that the concentration of 57Co-bleomycin (Co-bleo) in lung tumors reflects tumor cell kinetics and thus, prognosis. The relationship between the tumor concentration of Co-bleo measured in vivo by quantitative SPECT, response to chemotherapy and survival was investigated. METHODS: Twenty patients with small-cell lung carcinoma (SCLC) and 49 patients with non-small-cell lung carcinoma (NSCLC) were studied. The concentration of Co-bleo was measured by SPECT in vivo in the tumor. The correlation between Co-bleo concentration in the tumor and the fraction of Co-bleo bound to DNA was investigated in an EMT6 murine tumor model and in samples of eight human tumors. RESULTS: Tumors that did not respond to treatment showed a significantly higher Co-bleo concentration 8 hr after injection than tumors that responded (5.83% +/- 1.97% ID/cc * 10(-3) versus 2.55% +/- 1.23% ID/cc * 10(-3), p < 0.001). Values of Co-bleo concentration of 2.97% ID/cc * 10(-3) for SCLC and 2.72% ID/cc * 10(-3) for NSCLC were found to best separate patients into short- and long-term survival groups. In the EMT6 murine tumor model, a good correlation was found between the concentration of Co-bleo in the tumor and the fraction of Co-bleo bound to DNA (r = 0.75). In human tumor samples, a good correlation was found between DNA-bound Co-bleo measured in vitro and the concentration measured in vivo by SPECT (r = 0.85). CONCLUSIONS: SPECT-measured Co-bleo concentration predicts the response to treatment and the outcome in patients with lung tumor by showing Co-bleo binding to DNA and tumor cell kinetics.

Aged↗
PubMed1994

Bone turnover in cortical and trabecular bone in normal women and in women with osteoporosis.

UNLABELLED: This study is based on the assumption that is bone turnover, shown by the uptake of 99mTc-MDP, indicates a high rate of bone loss in patients with osteoporosis, it could potentially predict bone loss in patients at risk before significant bone loss has occurred. METHODS: Quantitative bone SPECT (QBS) using 99mTc-MDP, expressed as the %ID/cc x 10(-3), was performed in 71 women who had osteoporosis in the lumbar vertebrae, the femoral neck or both, and in 54 age-matched normal female controls. Of the women with osteoporosis, 42 had postmenopausal osteoporosis and 29 had primary hyperparathyroidism (HPT) and osteoporosis. RESULTS: QBS increased with age in the cortical bone and decreased in the trabecular bone of the normal women. Quantitative bone SPECT in the femoral neck was 3.18 +/- 1.20 and was 2.73 +/- 1.06 in the femoral shaft in 20 women with postmenopausal osteoporosis of the femoral neck. In 19 women with HPT and osteoporosis of the femoral neck, the QBS value in the femoral neck was 3.57 +/- 0.92 and in the femoral shaft 3.38 +/- 1.12. These values were also significantly higher for the femoral neck and for the femoral shaft than those of normals. Although QBS values were higher in the lumbar region in 39 women with postmenopausal osteoporosis (4.59 +/- 1.45) and in 27 women with HPT (4.30 +/- 1.52), as compared with the normal group (4.28 +/- 1.61), the difference was not statistically significant. CONCLUSION: This study shows that bone turnover is significantly higher in the cortical bone of women with osteoporosis than in normal women.

Bone Density↗
PubMed1993

Adjuvant arthritis is associated with changes in the glycosylation of serum IgG1 and IgG2b.

The increased amounts of agalactosyl IgG (N-linked oligosaccharides terminating with N-acetylglucosamine (GlcNAc) in the serum of patients with rheumatoid arthritis (RA) and other chronic inflammatory diseases have suggested that agalactosyl IgG may be involved in the pathogenesis of RA. We have now evaluated the incidence of agalactosyl IgG in the Lewis rat during the course of adjuvant arthritis (AA). The modification in glycosylation of IgG was measured by means of polyclonal and monoclonal anti GlcNAc antibodies as well as by the lectin concanavalin A (Con A). The results show that Lewis rats undergo a change in serum IgG glycosylation during the course of AA. As in human RA patients, rats with AA lack terminal galactose on IgG heavy chain oligosaccharides, and the terminal GlcNAc or mannose residues are thus exposed. The degree of agalactosyl IgG was positively correlated with the incidence of disease, peaked 20 days after disease induction, and the IgG gradually reverted to the fully glycosylated form thereafter. The post-arthritic glycosylation profile was very similar to that characteristic of the naive animal. Purified IgG was shown to contain two IgG subclasses, IgG1 and IgG2b, which underwent changes in glycosylation. Western blot analysis revealed that IgG1 expressed a higher degree of terminal mannose, whereas IgG2b expressed a higher degree of terminal GlcNAc. These findings raise the question of the possible involvement of agalactosyl IgG in immune complex-mediated inflammation.

Acetylglucosamine↗
PubMed1992

Marginal leakage of class II glass ionomer-composite resin restorations: an in vitro study.

This in vitro study assessed the sealing properties of two metal-reinforced glass ionomer cements, used as "extended bases" in glass ionomer-composite resin restorations. Two class II cavities were prepared in the proximal surfaces of 30 molars. The gingival margin of one was prepared in enamel and the other in cementum/dentin. Fifteen teeth (30 cavities) were restored with Ketac Silver material used as an extended base (group A). In the remaining 15 teeth (30 cavities), the extended base was in Miracle Mix material (group B). All occlusal surfaces were restored with Estilux Posterior Material. The restored teeth were thermocycled, immersed in fuchsin, washed in water, embedded, sectioned, and examined under a dissecting microscope. All restorations with margins in cementum/dentin of group A (Ketac Silver) leaked. No microleakage occurred in 12 of the 30 restorations with margins in cementum/dentin of group B (Miracle Mix). In addition, severe microleakage was present in 24 teeth of group A, as opposed to three in group B. It was concluded that the sealing properties of Miracle Mix material are superior to those of Ketac Silver material, in vitro.

Cermet Cements↗
PubMed1992

Local and systemic effects of radiation on bone metabolism measured by quantitative SPECT.

Quantitative bone scintigraphy (QBS), which measures 99mTc-MDP uptake expressed as percent of injected dose per cc, indicates bone metabolism. It is measured in the bones of patients before and after radiation treatment and then compared to normal controls. QBS was performed in a group of 22 normal individuals and was measured twice, 2-10 mo (mean 4.9) apart. There was no significant difference between the two measurements. QBS was performed also in 28 patients before, immediately after and at certain time intervals after radiation therapy for cancer. Both the irradiated and the nonirradiated bones showed significant decreases in bone metabolism at 2-18 mo (mean 8.8) after irradiation. In addition, increases and decreases of 99mTc-MDP uptake were similar in the irradiated and in the nonirradiated bones, and there were significant correlations of the QBS values in the different bones of each individual patient. The etiology of the changes in bone metabolism in the nonirradiated bones is not yet fully understood, but it appears to be the result of a systemic effect of radiation.

Bone and Bones↗
PubMed1992

Radionuclide assessment of penile corporal venous leak using technetium-99m-labeled red blood cells.

In an attempt to evaluate penile corporal venous outflow, a method that utilizes intracorporal injection of Tc-RBC was developed and used in 20 patients with erectile dysfunction. Seven patients showed venous leak and 13 had normal venous outflow. Technetium-labeled RBC corporal clearance in the flaccid state and after intracorporal injection of papaverine (30 mg) and regitine (1 mg) were assessed in sequence by two separate injections of 18.5 MBq of Tc-RBC each. The time for 50% corporal clearance (T50%) was determined from the time activity curves obtained in flaccid state and after intracorporal injection of the vasoactive agent. There were no statistically significant differences in T50% measured in the flaccid state between normal venous outflow (202 +/- 139 sec) and venous leak (92 +/- 35 sec, p = 0.1). However, after intracorporal injection of papaverine and regitine a significant increase in the T50% was noted in normal venous outflow (2892 +/- 1899 sec) as compared to venous leak (213 +/- 123 sec, p less than 0.001). The results suggest that measurement of corporal clearance of Tc-RBC after intracorporal injection of papaverine may be a useful method in detecting venous leak, and could be used as a screening test in patients with erectile dysfunction.

Adult↗
PubMed1991

In vivo measurements of the fraction of dose of bleomycin labeled with cobalt 57 delivered to human tumors.

Concentrations of bleomycin labeled with cobalt 57 (Co-bleo) over time were measured in vivo in 17 patients with 32 sites of lymphoma and 18 patients with lung tumors after administration of the same dose of bleomycin. There were marked variations in individual tumor drug concentrations even among tumors with the same histologic type, indicating that the tumor concentration of this drug in individuals cannot be predicted from the administered dose. Also, tumor concentration could not be predicted from the area under the concentration over time curve (AUC) of Co-bleo in the blood; there was no correlation (r = 0.53) between the AUC and the concentration in the tumor at any point in time between 30 minutes and 8 hours after injection. There was no significant difference in the percent of the injected dose per milliliter (%ID/ml) which was delivered to the tumor when low and high amounts of bleomycin were administered to the same patient. Also, a good correlation (r = 0.88) between the %ID/ml over time was found when injection of low and high doses of bleomycin were compared. The results indicate that using quantitative single photon emission computed tomography (SPECT) and a labeled tracer dose it is possible to predict what fraction of the dose of a chemotherapeutic drug will concentrate in an individual patient's tumor in vivo. They also show that, for bleomycin, escalation of dose will result in a proportional increase of tumor concentration. This increase depends on individual properties of tumors which can be measured quantitatively in vivo by SPECT and are expressed as percent of %ID/ml of tumor tissue.

Adolescent↗
PubMed1991

Effect of extracorporeal piezoelectric lithotripsy shock waves on renal function measured by Tc-99m-DMSA using SPECT.

Extracorporeal shock-wave lithotripsy has altered the therapeutic approach to urinary stone disease. Recently, a method was developed in which shock-wave generation is obtained piezoelectrically. To evaluate the effect of extracorporeal piezoelectric lithotripsy (EPL) on renal function, 20 patients were studied prior to and after EPL of renal calculi. Renal cortical function was evaluated by using a previously described and validated quantitative single photon emission computerized tomography (SPECT) method to measure individual absolute uptake of technetium-99m dimercaptosuccinic acid (Tc-99m-DMSA). Twenty kidneys were treated, and the 19 contralateral kidneys were without stone disease (1 patient had a single kidney). The absolute kidney uptake of Tc-DMSA in the normal kidneys was 21.4% +/- 6.2% before and 22.2% +/- 6.4% after EPL. For the treated kidneys the absolute update was 16.8% +/- 5.3% and 16.8% +/- 4.7% before and after, respectively. There was no statistical significant difference between pre- and post-treatment values. The absolute kidney uptake was significantly lower (p less than 0.01) in the treated than in the normal kidneys. This study indicates that the EPL procedure did not cause any damage to cortical function detectable by the DMSA uptake.

Adult↗
PubMed1991

Radionuclide assessment of bladder-emptying function in normal male population and in patients before and after prostatectomy.

Radionuclide assessment of the bladder-emptying function was evaluated in 82 normal individuals and in 16 patients before and after prostatectomy. The parameters evaluated were: average flow rate (AFR), peak flow rate (PFR), corrected peak flow rate (CPFR = PFR/[bladder volume] 0.5), ejection fraction (EF) of the bladder, and post-voiding residual urine (RU) volume. A good interobserver reproducibility was found in 19 measurements. Urinary flow rates, EF, and RU showed a highly significant statistical difference between normal individuals and patients before surgery: AFR, 9.2 +/- 5.1 vs. 2.9 +/- 1.5 mL/sec; PFR, 19.5 +/- 9.2 vs 7.4 +/- 3.2 mL/sec; CPFR, 1.17 +/- 0.34 vs 0.54 +/- 0.22; EF, 95.6 +/- 4.6 vs 68.2 +/- 23.2 percent; and RU, 11.8 +/- 15.8 vs 93.4 +/- 115 mL; respectively. After prostatectomy the urinary flow rates showed a highly significant improvement and did not differ from the normal individuals: AFR, 7.9 +/- 2.7 mL/sec; PFR, 19.0 +/- 6.4 mL/sec; and CPFR, 1.32 +/- 0.57. The EF after surgery (91.7 +/- 10.9%) was lower than in normal individuals, but showed a significant improvement compared with EF before surgery. The RU after surgery (27.4 +/- 48.0 mL) although lower than before surgery did not differ significantly and was greater than in the normal individuals. No relationship between age and flow was found in this study. Both average and peak flow rates were related to the bladder volume. This method involves a single, noninvasive procedure which enables determination of bladder-emptying function.

Adult↗
PubMed1991

Marginal leakage around V-shaped cavities restored with glass-ionomer cements: an in vitro study.

The object of this investigation was to assess the degree of marginal leakage around V-shaped cervical glass-ionomer cement restorations and compare it to that around composite resin restorations. Three different glass-ionomer cements and one composite resin control were assessed by means of dye penetration. Severe microleakage at the occlusal margins was found in 70% of the glass-ionomer cement restorations, but in only 10% of the composite resin restorations. A considerable amount of dye penetration was observed at the cervical margins of all restorations, including the controls. None of the glass-ionomer cements tested showed superiority in preventing marginal leakage occlusally or gingivally.

Bicuspid↗
PubMed1991

Renal function and technetium-99m-dimercaptosuccinic acid uptake in single kidneys: the value of in vivo SPECT quantitation.

The ability to evaluate kidney function in each kidney separately by quantitative SPECT was tested in 20 patients with a single kidney and varying degrees of renal disease. Technetium-99m-dimercaptosuccinic acid (99mTc-DMSA) uptake was compared with renal function measured by creatinine clearance and serum creatinine. There was a good correlation for both serum creatinine (r = 0.89, y = 24.6 *X -1.15, error = 5.6, p less than 0.001) and creatinine clearance (r = 0.76, y = 0.6 *X 0.84, error = 8.0, p less than 0.001). The results indicate that SPECT quantitation of 99mTc-DMSA uptake can be used as an indicator of the function of each kidney individually.

Adult↗