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Biomedical subjects

I M Schicht

Publications and source records attributed to I M Schicht.

13 recordsLinked to original sources
PubMed1984

Observations on computerized quantitative bone scintigraphy in renal osteodystrophy.

Skeletal radiotracer (99mTc-HEDP) uptake was quantitated with and without the aid of a computer in 30 chronic dialysis patients with histologic evidence of renal osteodystrophy. Before scintigraphy, elevated soft-tissue activity due to the absence of renal radiotracer excretion was reduced by hemodialysis. The results were compared with those of a normal group and with the results of the biochemical and the bone morphometric studies of these patients. In all patients the radiotracer uptake was elevated, often markedly. In several patients with minimal histologic bone disease, however, soft-tissue activity could not be normalized by hemodialysis although its influence on the quantitative data could be further reduced (but not excluded) by computer evaluation of skeletal radiotracer uptake. Since the latter technique clearly distinguished the majority of the patients from the normals, it appears that computerized quantitative skeletal analysis is a potentially accurate scintigraphic method for detecting renal osteodystrophy. The significant relationship between skeletal radiotracer uptake, in particular at the bone biopsy site, and only the histologic features of increased bone turnover suggest that hyperparathyroidism is the major cause of this increased tracer uptake in renal osteodystrophy.

Adolescent↗
PubMed1984

The immunochemical determination of apolipoprotein A, total apolipoprotein A-I and 'free' apolipoprotein A-I in serum of patients on chronic haemodialysis.

We have determined by radial immunodiffusion the apolipoprotein A content of undelipidated serum samples from 30 patients on chronic haemodialysis and 28 controls using an antiserum against high density lipoprotein (anti-apolipoprotein A). We found that the patients had lower concentrations of apolipoprotein A than the controls. When an antiserum against apolipoprotein A-I was used and the samples were delipidated prior to radial immunodiffusion there was, however, no difference in the total amount of apolipoprotein A-I between the two groups. We were able to explain this difference by measuring the amount of 'free' apolipoprotein A-I after crossed immunoelectrophoresis of undelipidated samples, using the antiserum against apolipoprotein A-I. We found that the patients had a higher level of 'free' apolipoprotein A-I than the control group. Since apolipoprotein A-I inhibits hepatic triglyceride lipase, the increase in triglycerides observed in patients on haemodialysis may be caused by the greater concentration of 'free' apolipoprotein A-I in their serum.

Adult↗
PubMed1982

Increased bone radiotracer uptake in renal osteodystrophy. Clinical evidence of hyperparathyroidism as the major cause.

Bone radiotracer uptake in renal osteodystrophy was investigated in 35 dialysis patients by correlating the results of quantitative bone scintigraphy with those of biochemical and bone morphometric studies. There were highly significant correlations (P less than 0.001) between the total skeletal activity and the biochemical (iPTH and alkaline phosphatase), and histologic parameters of hyperparathyroidism. These clinical results strongly suggest that increased bone turnover i.e. hyperparathyroidism, rather than osteomalacia is the major cause of increased skeletal uptake in renal osteodystrophy.

Adolescent↗
PubMed1980

Effects of an angiotensin-converting enzyme inhibitor (captopril) on blood pressure in anephric subjects.

Randomised, double-blind cross-over trials were performed in seven anephric patients to determine the effect of the orally active angiotensin-converting enzyme inhibitor captopril on blood pressure in fluid-depleted and fluid-replete patients. Patients were given captopril, 100 mg orally, or placebo one hour after haemodialysis, when they were fluid depleted. Their mean (+/- SEM) supine blood pressure fell from 127 +/- 12/71 +/- 6 mm Hg before captopril to 106 +/- 13/54 +/- 4 mm Hg 24 hours after the drug, while on placebo it rose from 123 +/- 11/73 +/- 5 mm Hg to 134 +/- 10/82 +/- 8 mm Hg. All patients developed orthostatic hypotension after captopril. In the fluid-replete state, two days after haemodialysis, captopril had no effect on blood pressure. The plasma concentration of active renin was extremely low and did not rise after fluid withdrawal or captopril. Thus the hypotensive effect of captopril did not appear to depend on circulating renin concentrations. The concept of "renin-dependent" hypertension, which is responsive to captopril, as opposed to "volume-dependent" hypertension, which is not responsive to captopril, may therefore be invalid.

Adult↗
PubMed1980

Metastatic skin calcification. A rare phenomenon in dialysis patients.

Calcification of the skin could not be demonstrated in 60 skin biopsy specimens, selectively obtained from 30 chronic hemodialysis patients; 21 of these patients had metastatic calcification at other sites. These results support the proposed rarity of metastatic skin calcification in patients with chronic renal failure. The cause of this phenomenon is not precisely known.

Adolescent↗
PubMed1979

Scintigraphic detection of gastric calcification in dialysis patients.

The value of 99mTc HEDP bone scintigraphy as a means of detecting metastatic gastric calcification was studied in 45 chronic dialysis patients and in 55 former dialysis patients. For this group, all bone scans were obtained within 2 months after successful transplantation; radiotracer uptake by the stomach was not observed. In 15 of the first 35 chronic dialysis patients studied, gastric uptake was demonstrated without radioactive accumulation in the thyroid region. In all the dialysis patients, however, background activity had been normalized before scintigraphy by means of hemodialysis using recirculating dialysate. Without the latter, radioactive accumulation in the stomach was no longer noted. Thus, gastric uptake was presumably due to the formation of in vivo free pertechnetate, as a result of the dialysis method used, and in vitro experiments supported this hypothesis. These findings show that free pertechnetate can cause visualization of the stomach in the absence of thyroid imaging. The results of this study further indicate that bone scintigraphy is not a sensitive method for detecting metastatic gastric calcification in uremia.

Adolescent↗
PubMed1978

Bone scintigraphy in renal osteodystrophy.

Bone scintigraphy with Tc-99m HEDP was performed in 30 patients on maintenance hemodialysis, and the results of quantitative analysis were compared with those of a normal group. To permit this comparison, elevated background activity due to the absence of renal radiotracer excretion was reduced by hemodialysis to levels found in the normals. Histologic proof of renal osteodystrophy had been obtained in all patients. The incidence of radiographic abnormalities was 46%, whereas abnormal scans were found in 25 patients (83%); skeletal lesions were also more pronounced and detected earlier. However, even when the scans appeared normal, the quantitative analysis showed increased skeletal activity in all patients. The total skeletal activity proved to be a good index of the severity of renal osteodystrophy and appeared dependent on both osteomalacia and hyperparathyroidism. These findings show that bone scintigraphy is a sensitive method to detect skeletal involvement in renal osteodystrophy.

Adolescent↗