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Biomedical subjects

S Schifter

Publications and source records attributed to S Schifter.

At least 55 records · Page 3Linked to original sources
PubMed1992

Clinical pharmacokinetic studies of a human haemopoietic growth factor, GM-CSF.

The pharmacokinetics of glycosylated recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) was studied following intravenous (i.v.) and subcutaneous (s.c.) bolus injection of rhGM-CSF, 8 micrograms kg-1 employing a sensitive radioimmunoassay. After a single i.v. bolus injection, an initial high serum level of rhGM-CSF was observed, followed by a rapid decrease that occurred in two phases with a half-life (t1/2) alpha of 20.0 +/- 5 min and a t1/2 beta of 68.3 +/- 8 min. Following s.c. bolus injection the absorption was more prolonged. Peak serum concentrations did not occur until about 15-20 h, and were followed by a more protracted elimination than by the i.v. route. In all patients the single rhGM-CSF injection led to an increase in peripheral white blood cells (WBC), after a temporary drop of 2-5 h duration. The increase in WBC was of longer duration after s.c. than after i.v. bolus treatment. Since the subcutaneous administration leads to prolonged serum concentration of rhGM-CSF and prolonged increase in peripheral WBC, it seems preferable to i.v. bolus injection, and as effective as continuous i.v. infusion.

Adult↗
PubMed1992

In vivo kinetics of 111indium-labelled autologous granulocytes following i.v. administration of granulocyte-macrophage colony-stimulating factor (GM-CSF).

Administration of both glycosylated and non-glycosylated recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) induces an immediate transient granulocytopenia of 1-3 hours' duration. In order to explore this phenomenon, granulocytes were labelled with 111Indium and the effect on the kinetics of granulocytes after administration of rhGM-CSF was studied in 10 previously untreated patients with malignant lymphoma. For both types and doses of rhGM-CSF, a significant and dramatic accumulation of the 111Indium-labelled granulocytes was observed in the lung within a few minutes after i.v. injection of rhGM-CSF. The accumulation of radioactivity coincided with the pronounced and transient granulocytopenia in peripheral blood. The 111Indium-labelled granulocytes later reappeared in the peripheral blood, indicating reversible pulmonary vascular margination of the granulocytes. Half-life of labelled granulocytes after reappearance was comparable to half-life values under normal conditions. The transient accumulation of granulocytes in the pulmonary vessels seems not to be of clinical importance in the management of patients, but it may to some degree explain previously described side-effects, such as transient hypoxemia ("first-dose" reaction) following administration of rhGM-CSF.

Agranulocytosis↗
PubMed1991

Increased circulating calcitonin gene-related peptide (CGRP) in cirrhosis.

The etiology of the hyperkinetic circulatory state in cirrhosis is equivocal and reduced peripheral vascular resistance is a major unsolved problem in hepatic pathophysiology. It is therefore sensible to search for vasodilators. A recently discovered neuropeptide, calcitonin gene-related peptide (CGRP), is a highly potent vasodilator. We determined the circulating concentration of immunoreactive CGRP in different vascular beds in 35 patients with cirrhosis and in eight patients with minor disorders. Plasma CGRP was significantly increased in the cirrhotic patients compared with patients with minor disorders (59 vs. 46 pmol/l, p less than 0.01), as well as with 232 healthy persons (37 pmol/l, p less than 0.0001). Moreover, circulating CGRP increased significantly with the severity of cirrhosis (Child-Turcotte group A, 56; group B, 59; group C, 71 pmol/l; p less than 0.025). No significant arterio-venous net extraction or release of CGRP was found across the hepato-intestinal system, kidney, lung or limb. In conclusion, elevated circulating CGRP may play a role in the haemodynamic derangement of cirrhosis. The lack of organ arterio-venous differences suggests a widespread release and degradation of CGRP in many tissues and gives no evidence of decreased degradation as the cause of increased plasma CGRP in patients with cirrhosis.

Adult↗
PubMed1991

Processing of pro-CGRP in a rat medullary thyroid carcinoma cell line transfected with protease inhibitors.

A rat medullary thyroid carcinoma cell line, CA77, was used to study the effect of a series of biosynthesized protease inhibitors on the proteolytic cleavage of the endogenously synthesized pro-CGRP. This cell line efficiently converted the pro-CGRP to mature CGRP as assessed by chromatography of cell extracts followed by radioimmunoassay for CGRP. CA77 cells were transfected with expression vectors encoding protease inhibitors: the Arg-serpins, alpha 1-antitrypsin Pittsburgh (358 Met----Arg) and plasminogen activator inhibitor 1, the Kazal type serine protease inhibitor, pancreatic secretory trypsin inhibitor, and the general thiol protease inhibitor, cystatin C. Only the chromatography of cell extracts from CA77 cells transfected with a plasmid encoding cystatin C showed an apparent higher content of unprocessed pro-CGRP as compared to non-transfected cells. No effect on pro-CGRP processing could be measured in the CA77 cells transfected with plasmids encoding the three serine protease inhibitors. CA77 cells were also transfected with two constructs encoding chimeric proteins consisting of cystatin C and the precursor for neuropeptide Y. Release experiments using 8-bromo cAMP as the secretagogue showed that the chimer was co-released with CGRP. However, no effect of this chimer upon pro-CGRP processing could be detected. It is concluded that the processing of pro-CGRP in the CA77 cell line was very efficient and that four different protease inhibitors and two cystatin C/NPY chimers synthesized by this neuroendocrine cell line had only minimal effect upon the processing of CGRP.

Animals↗
PubMed1991

Normal serum levels of calcitonin gene-related peptide (CGRP) in mild to moderate essential hypertension.

Calcitonin gene-related peptide (CGRP), a highly potent vasodilator, is expressed from the calcitonin-gene and has been localized to nerve fibers of the cardiovascular system, suggesting involvement in the physiologic regulation of vascular tone. In this investigation serum concentrations of CGRP were measured in patients with untreated mild to moderate essential hypertension (WHO I-II) and compared with concentrations in sex- and age-matched normal controls to assess a possible relationship between changes in concentrations of CGRP and this condition. The study showed no significant difference in concentrations of CGRP between patients and the normotensive controls. However, a weak but significant positive correlation was found between systolic (SBP), diastolic (DBP), mean blood pressures (MBP), and circulating concentrations of CGRP when calculated for all individuals included in the study. No correlation was found between heart rates (HR) and concentrations of CGRP. In the normotensive control group, but not in patients with hypertension, a significant positive correlation was present between body weights and concentrations of CGRP. These findings do not support the hypothesis that low expression of CGRP plays a causal role in essential hypertension, but the results do not exclude a potential receptor defect for CGRP to be involved in the disease.

Calcitonin Gene-Related Peptide↗
PubMed1991

Calcitonin gene-related peptide (CGRP) and leg vascular resistance during head-up tilt induced hypovolaemic shock in man.

Calcitonin gene-related peptide is a potent vasodilator and its distribution in perivascular nerves suggests a role in the regulation of vascular tone. We evaluated leg vascular resistance together with total peripheral resistance and the arterial plasma concentrations of calcitonin gene-related peptide and catecholamines during 50 degrees head-up tilt induced hypotension in 7 males. During tilt mean arterial pressure, heart rate, total peripheral resistance, leg vascular resistance and plasma noradrenaline increased, while cardiac output and leg blood flow decreased. After 45 +/- 9 min (mean +/- SE) presyncopal symptoms appeared together with decreases in mean arterial pressure (81 +/- 6 to 56 +/- 9 mmHg), heart rate (97 +/- 6 to 73 +/- 8 beats min-1), leg vascular resistance (158 +/- 9 to 109 +/- 8 mmHg min l-1) and total peripheral resistance (17 +/- 3 to 10 +/- 2 mmHg min l-1) (P less than 0.01). Plasma calcitonin gene-related peptide increased from 32 +/- 3 to 35 +/- 3 pmol l-1 (P less than 0.01) and adrenaline from 1.1 +/- 0.2 to 1.7 +/- 0.3 nmol l-1 (P less than 0.01), while noradrenaline did not change. The results indicate that presyncopal symptoms induced by head-up tilt are associated with regional as well as total decreases in vascular resistance accompanied by moderate increases in arterial plasma concentrations of calcitonin gene-related peptide and adrenaline.

Adult↗
PubMed1991

Circulating levels of calciotropic hormones during treatment with nasal salmon calcitonin.

Circulating levels of calciotropic hormones were measured during one year of treatment with either 200 IU of salmon calcitonin daily or placebo as a nasal spray in 20 postmenopausal women with a former Colles' fracture. A supplement of 0.5 gram elemental calcium was given to all participants. Serum levels of parathyroid hormone and human calcitonin were determined with radioimmunoassays, and serum levels of vitamin D metabolites were determined with protein binding assays. We did not find any significant differences between the two groups with respect to serum levels of calciotropic hormones. In the salmon calcitonin treated group there was a tendency towards a small decrease in serum levels of human calcitonin and an increase in serum levels of calcitriol. Our results suggest that treatment with 200 IU of salmon calcitonin daily as a nasal spray does not markedly affect fasting serum levels of parathyroid hormone, human calcitonin, and vitamin D metabolites.

Administration, Intranasal↗
PubMed1990

Expectoration in the gastrointestinal tract. A diagnostic problem in In-111 granulocyte scintigraphy.

Scintigraphic detection of infectious foci with In-111 labeled granulocytes or leukocytes is a well-established technique in nuclear medicine. The technique is commonly used to demonstrate inflammatory activity in Crohn's disease and ulcerative colitis. Its application, however, may be influenced by infectious expectoration located within the gastrointestinal tract. In performing this technique, it is important to have this differential diagnostic possibility in mind; it can be clarified by repeated imaging.

Adult↗
PubMed1990

Non-sulphated cholecystokinin in human medullary thyroid carcinomas.

The expression of gastrin/cholecystokinin (CCK) peptides and their precursors was examined in 16 medullary carcinomas of the human thyroid. Measurements with libraries of sequence-specific radioimmunoassays before and after enzymatic cleavage of extracts and chromatographic fractions showed that the carcinomas contained 1.7 pmol carboxyamidated CCK/g tissue (median; range 0.6-21.8 pmol/g), 0.9 pmol glycine-extended precursor/g (median; range less than 0.2-2.3 pmol/g) and 2.3 pmol further COOH-terminal-extended proCCK/g (median; range 0.9-6.2 pmol/g). Neither carboxyamidated gastrins nor any progastrins could be measured. Gel and reverse-phase chromatography revealed only small molecular forms, i.e. greater than 90% of the amidated immunoreactivity eluted like non-sulphated CCK-8 or CCK-7. The results show that human medullary thyroid carcinomas synthesize CCK peptides. The predominance of non-sulphated CCK is unusual. Taken together with earlier observations from dogs and pigs, our results raise the possibility that small non-sulphated CCK peptides modulate thyroid C-cell secretion in an autocrine manner.

Amino Acid Sequence↗
PubMed1989

Elevated serum levels of calcitonin gene-related peptide (CGRP) but no evidence for CGRP gene expression in non-small cell lung carcinomas.

Calcitonin gene-related peptide (CGRP) is a hormone formed by alternative post-transcriptional processing of the calcitonin gene. It is a neuropeptide localized to discrete regions of the central nervous system (CNS) and in nerve fibres associated with blood vessels. It is also expressed in medullary carcinomas of the thyroid and lung carcinoma cell lines. The latter finding suggests a possible value for CGRP as tumour marker in lung carcinomas. In this investigation of 22 patients undergoing operation for lung tumours, pre and post-operative levels of serum CGRP were measured. Preoperative as well as postoperative serum CGRP levels were significantly elevated when compared to age-matched normals. However, no evidence could be found for CGRP gene expression in tumour tissue from the same patients as judged by immunocytochemistry or in-situ hybridization using CGRP cRNA probes. CGRP has been localized to nerve fibres in relation to pulmonary blood vessels and has been shown to be a potent vasodilator. These findings, and the absence of evidence for synthesis in tumours, as opposed to cell lines derived from lung carcinomas, suggests that the lack of post-operative normalization of serum CGRP concentrations may be related to physiological changes in cardiovascular haemodynamics following surgery. Elevated pre-operative serum CGRP levels may also reflect a consequence of the lung carcinoma leading to increased release of CGRP from sites in the vasculature yet to be determined, but does not indicate synthesis de novo and secretion of CGRP by the tumours.

Biomarkers, Tumor↗
PubMed1989

Calcitonin gene-related peptide and calcitonin as tumour markers in MEN 2 family screening.

This investigation deals with the potential additional value of serum CGRP measurements as compared to calcitonin in screening for medullary carcinoma of the thyroid (MTC) in families with multiple endocrine neoplasia type 2 (MEN 2). Basal as well as pentagastrin-stimulated values for CGRP are evaluated in relation to the corresponding levels for calcitonin. Serum CGRP is within normal range in most family members with pathological calcitonin response to the pentagastrin stimulation test. Furthermore, these potentially affected family members do not respond to the pentagastrin stimulation test with an increase in CGRP. Pentagastrin stimulation tests performed in patients with manifest MTC affect the serum CGRP levels inconstantly and in two patients, with elevated basal level of CGRP, stimulation caused a release of calcitonin while concentrations of CGRP remained unaffected. We conclude that determination of serum CGRP adds no information to that of serum calcitonin in MEN 2 family screening for MTC.

Adolescent↗
PubMed1989

Changing electrocardiographic findings in pulmonary embolism in relation to vascular obstruction.

Electrocardiographic (ECG) findings in 87 consecutive patients with from minor to massive pulmonary embolism are presented. ECG changes suggestive of acute right ventricular strain defined as the occurrence of complete (c) or incomplete (inc) right bundle branch block (RBBB), an SIQIIITIII pattern, inverted T waves in the second and third precordial leads and/or an increase in the frontal QRS axis of 20 degrees C or more were found in 71 patients (82%). The prevalence of c and inc RBBB and the increase in frontal QRS axis correlated with the extent of embolization (angiographic or scintigraphic score), while the appearance of the SIQIIITIII pattern did not. No patient with a vascular obstruction of two thirds or more had an ECG free of signs of right ventricular strain. In 9 of 11 embolectomized patients with c RBBB, c RBBB disappeared within 24 h postoperatively. Among patients with an embolization of 45% or more, those with c RBBB had a shorter symptom duration, fewer embolic episodes and a lower pulmonary artery pressure than those without c RBBB. As ECG abnormalities were transient and changing in nature, serial ECG recordings are recommended. Pronounced ECG signs of right ventricular strain should, as they may reflect both massive and short-lasting vascular obstruction, arouse the suspicion of pulmonary embolism suitable for embolectomy.

Adolescent↗
PubMed1988

Early detection of response in small cell bronchogenic carcinoma by changes in serum concentrations of creatine kinase, neuron specific enolase, calcitonin, ACTH, serotonin and gastrin releasing peptide.

Creatine kinase (CK-BB), neuron specific enolase (NSE), ACTH, calcitonin, serotonin and gastrin releasing peptide (GRP) were measured in serum or plasma before and immediately after initiation of treatment in patients with small cell lung cancer (SCC). Pretherapeutic elevated concentrations of CK-BB were found in 82% of extensive disease patients and in 50% of patients with local disease. NSE was raised in 72% with extensive disease versus 14% of patients with local disease. Calcitonin and ACTH were raised in 27% and 28%, respectively, in all patients without significant difference between extensive and local disease patients. Serotonin was generally overall elevated in 10% and GRP in 7% but elevations were seen only in patients with extensive disease. Out of the four most frequently elevated substances at least one marker was elevated in 80% of all the patients, including 91% in extensive stage patients and 71% in limited stage patients. Frequent initial monitoring of the substances showed an increase in the concentrations of pretherapeutic elevated CK-BB and NSE on day 1 or 2 followed by a sharp decrease within 1 week. These changes were correlated to objective clinical response determined within 4-8 weeks. The results indicate that serum CK-BB and NSE are potential markers for SCC at the time of diagnosis and that changes in the concentrations during the first course of cytostatic therapy are promising as biochemical tests for early detection of response to chemotherapy.

Adrenocorticotropic Hormone↗
PubMed1988

Effects of human calcitonin gene-related peptide and substance P on human intracervical arteries.

The contractile effects of substance P and human calcitonin gene-related peptide (human CGRP) on isolated human intracervical arteries were studied. Human cervical tissue specimens were excised after hysterectomy at various phases of the menstrual cycle (n = 14) and small intracervical arteries were dissected free by microtechnique. Ring preparations of the vessels were prepared and mounted in organ baths, and isometric circular tension was recorded. Neither compound affected resting tension. Both peptides showed potent relaxing effects on vessels precontracted by noradrenaline 10(-5) M. Substance P exhibited the higher potency, while human CGRP showed the higher efficacy. The relaxing effects of the two compounds were unaffected by pretreatment with indomethacin 10(-6) M, propranolol 10(-6) M and atropine 10(-6) M. The results support a role for the two peptides in the regulation of cervical blood flow.

Arteries↗
PubMed1987

Pulmonary embolism: long-term follow-up after treatment with full-dose heparin, streptokinase or embolectomy.

The study comprises 74 patients alive 30 days after the start of treatment of pulmonary embolism with heparin (n = 32), streptokinase (n = 22) or embolectomy (n = 20). The cumulative 5-year survival was 100% in the embolectomy group, compared to 75 +/- 7% (SE) in the medically treated patients (p less than 0.05). Cancer caused 78% of the late deaths. At follow-up 0.5-8.7 years after treatment the treatment groups were indistinguishable as regards right-sided heart catheterization data, pulmonary artery rest-obstruction, right ventricular diameter and wall thickness, ventilatory function and ECG changes. The embolectomized patients were in a more favourable NYHA classification level than the medically treated. Chronic pulmonary artery hypertension was found in 75% of patients with greater than or equal to 3 anamnestic recurrent embolic episodes before diagnosis compared to 8% of patients with less than or equal to 2 recurrent episodes (p less than 0.001). Patients with irreversible cardiocirculatory shock before embolectomy all had abnormal pulmonary vascular resistance (greater than 1.5 mmHg/l/min), depressed ventilatory function and more than 25% reduced pulmonary perfusion at follow-up. The major prognostic factors thus were cancer, the number of recurrent episodes and the degree of cardiocirculatory affection in the acute event. Although the embolectomized patients were the most affected initially, they had a good prognosis. This led us to extend our indications for embolectomy to include all patients with central emboli, irrespective of the degree of cardiocirculatory impairment.

Adolescent↗