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Biomedical subjects

C Peters

Publications and source records attributed to C Peters.

At least 235 records · Page 13Linked to original sources
PubMed1990

Capillary leak syndrome during low dose granulocyte-macrophage colony-stimulating factor (rh GM-CSF) treatment of a patient in a continuous febrile state.

A 20 years old man with peripheral primitive neuroectodermal tumor involving the bone marrow received 12 Gy fractionated total body irradiation, 140 mg/m2 melphalan, 1800 mg/m2 etoposide, and 1500 mg/m2 carboplatin for consolidation of first remission. Thereafter, 250 micrograms/m2/day recombinant human granulocyte-macrophage colony-stimulating factor (rh GM-CSF) (Behring Werke) were administered as continuous infusion 4 days after infusion of autologous bone marrow and peripheral stem cells to accelerate granulocyte reconstitution for control of a continued febrile state. The clinical picture of capillary leak syndrome developed with weight gain, pleural effusions and peripheral edema. The patient's condition stabilized after discontinuation of rh GM-CSF. Eight days later he died of invasive aspergillosis. The clinical course of our patient suggests a potentially fatal toxic effect of rh GM-CSF, even in low dose, in the setting of septicemia or fungemia.

Adult↗
PubMed1990

Regulation of megakaryocyte phenotype in human erythroleukemia cells.

Induction of human erythroleukemia (HEL) cells with nanomolar tumor-promoting phorbol myristate acetate (PMA) diesters results in the synchronous acquisition of multiple markers of the megakaryocyte phenotype. Induced cells markedly increase their content of cytoplasm and show features of morphological maturation. At the ultrastructural level, PMA-treated cells show increases in cytoplasm, nuclear lobulation and nucleolar content, and free ribosomes. Limited numbers of cells also express alpha-granules and nascent demarcation membrane systems. Functionally, PMA-stimulated HEL cells express increased amounts of the megakaryocyte/platelet proteins: glycoprotein IIb/IIIa, platelet factor 4, von Willebrand factor, glycoprotein Ib, and thrombospondin. No changes are observed in antigenic markers of the erythroid (glycophorin A) or macrophage lineages (MO-1 or MO-2). The increases in antigenic expression are rapid, reaching maximum levels within 3-4 d under serum-free conditions. Treatment with PMA also abruptly (within 1-2 d) inhibits cellular division in these cells. Washout studies indicate that phorbols exert their effect within 18-24 h, the approximate cell cycle time for these cells. Consistent with proliferative arrest, c-myc proto-oncogene transcripts begin to decline within 8 h of PMA treatment, although transcripts of c-myb are unaffected. Importantly, megakaryocyte differentiation is associated with endomitotic DNA synthesis (i.e., continued DNA synthesis in the absence of mitosis and cytokinesis), with HEL cells reaching a DNA content of 3-12 times that of unstimulated cells. Endomitosis is coordinately regulated with changes in antigenic expression and cell size such that those cells having the highest DNA content are the largest and also express the greatest levels of antigen.

Antigens↗
PubMed1990

The median rise of leucocytes predicts the optimal days for leukapheresis in children.

22 consecutive patients with a median age of 11 years (range 3-23) underwent 103 leucaphereses after a chemotherapy induced aplasia. They suffered from various solid tumors and hematological malignancies. The stem cell yield of 69 aphereses which were done during the 8 days following the first platelet rise, was median 1.02 x 10(4) myeloid committed stem cells (CFU-GM)/kg/apheresis (range 0.02-13.3), whereas only 0.27 x 10(4) CFU-GM/kg/apheresis (range 0.01-1.11) were obtained in 34 "random" collections (p less than .05). The CFU-GM yield of 69 "well timed" collections depended on the absolute number of circulating leucocytes (p = .002) and mononuclear cells (p less than .001). The median daily increment of leucocytes was a reliable predictor of the stem cell yield (p = .002) and could be used to select the optimal days for leucaphereses during the well timed period. By careful timing alone high stem cell numbers could be collected in various malignancies without using exogenous growth factors.

Adolescent↗
PubMed1989

High degree of homology between primary structure of human lysosomal acid phosphatase and human prostatic acid phosphatase.

Alignment of the amino-acid sequences of the human lysosomal acid phosphatase (LAP) and human prostatic acid phosphatase (PAP) yielded an extensive homology between the two mature polypeptide chains. In the overlapping part, which extends over the entire PAP sequence and the N-terminal 90% of the LAP sequence, the identity is 49.1%. The LAP has an additional C-terminal sequence, which is encoded by the last exon of the LAP gene. This sequence contains the transmembrane domain of LAP, which is lacking in the secretory PAP. All six cysteine residues as well as 20 out of 27 (LAP) and 26 (PAP) proline residues present in the overlapping part of the proteins are conserved, suggesting that they are involved in stabilization of the tertiary structure of both proteins. Only two out of 8 N-glycosylation sites in LAP and 3 in PAP are conserved, suggesting that the dense N-glycosylation of LAP is related to its function in lysosomes.

Acid Phosphatase↗
PubMed1989

Blepharoplasty.

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Eyelids↗
PubMed1989

Rhinoplasty.

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Humans↗
PubMed1988

Inotropic, vascular and neuroendocrine effects of dopexamine hydrochloride and comparison with dobutamine.

Dopexamine hydrochloride is a novel beta 2- and dopaminergic-receptor agonist proposed for intravenous therapy in patients with congestive heart failure. To gain a clearer knowledge of its efficacy relative to other agents, intravenous infusions of dopexamine hydrochloride (4 micrograms/kg/min) and dobutamine (10 micrograms/kg/min) were administered to 10 patients with congestive heart failure (ejection fraction less than 0.4). Both agents increased stroke volume and cardiac indexes to a similar degree, and both decreased systemic vascular resistance, with a trend toward a greater decrease with dopexamine hydrochloride. Although dobutamine had no significant effect on left ventricular systolic pressure, dopexamine hydrochloride caused a decrease from 121 +/- 8 to 110 +/- 7 mm Hg (p less than 0.01). Both dobutamine and dopexamine hydrochloride increased peak rate of left ventricular pressure development (dP/dt), and there was a trend to a greater increase with dobutamine (control 1,043 +/- 102 mm Hg/s; dobutamine 1,340 +/- 142 mm Hg/s; dopexamine hydrochloride 1,213 +/- 120 mm Hg/s, p = 0.067 vs dobutamine). Plasma norepinephrine levels increased only with dopexamine hydrochloride (+49%, p less than 0.05). Plasma renin activity increased with both agents (dobutamine +38%, p less than 0.06; dopexamine hydrochloride +41%, p less than 0.05). Dobutamine and dopexamine hydrochloride, therefore, improve cardiac function by way of both vasodilator and inotropic mechanisms. At the doses administered, dopexamine hydrochloride relies on a greater systemic vasodilator effect than dobutamine to achieve and increase in left ventricular performance. Increased levels of endogenous catecholamines may contribute to the increased inotropic state with dopexamine hydrochloride.

Blood Pressure↗
PubMed1988

Upper extremity radionuclide venography in the diagnosis and management of venous disease associated with intravenous catheters.

The utility of upper extremity radionuclide venography (RNV) in the assessment of suspected catheter-related central venous thrombosis (CRVT) was evaluated in 40 patients with subclavian venous catheters. Twenty normal patients (Group A) served as controls and their venographic patterns were analyzed by using four criteria: (1) delayed tracer transit time, (2) nonuniformity of flow and venous pooling, (3) jugular venous reflux, and (4) collateral venous filling. Control studies displayed no collaterals as a distinguishing characteristic but demonstrated the other three features to a variable degree. Of 106 extremities suspected of CRVT, 67 (Group B) were initially considered to have normal RNV findings (no collaterals). Contrast venography confirmed a normal pattern in 3 but identified CRVT with collaterals in 3 others. Retrospective review of the RNV studies confirmed faint collaterals in these latter 3. The 39 remaining extremities (Group C) showed abnormal RNV findings; contrast venography and postmortem studies confirmed the presence of venous disease in 5 patients. The authors believe that RNV is a reliable, noninvasive procedure for early diagnosis of venous occlusion associated with subclavian venous catheters.

Blood Flow Velocity↗
PubMed1988

Homozygous protein C deficiency: observations on the nature of the molecular abnormality and the effectiveness of warfarin therapy.

An infant with severe homozygous protein C deficiency was brought to medical attention because of purpura fulminans and severe bilateral vitreous hemorrhages in the neonatal period. Infusions of fresh frozen plasma were given for 8 months. On two occasions, attempts to decrease the frequency of fresh frozen plasma infusions to less than twice a day led to episodes of microangiopathic hemolysis, fibrinolysis, and acute renal failure. Infarction of skin and subcutaneous tissues did not recur. Both episodes were controlled after reinstitution of fresh frozen plasma. Complications of therapy with fresh frozen plasma included hyperproteinemia and hypertension. Warfarin therapy was instituted when the baby was 8 months of age, followed by a gradual withdrawal of fresh frozen plasma therapy. The dose of warfarin required to maintain the prothrombin time in a range of 1.8 to 2.2 times normal varied considerably during short periods, a phenomenon that may have been due to several factors: hypercatabolism of the drug with prolonged administration, abnormality of liver function, variation in levels of serum albumin, fluctuations in drug dosage secondary to oral administration, and variations in dietary vitamin K. Protein C determinations by immunologic and functional assays consistently showed detectable but reduced protein C antigen levels with undetectable activity levels, suggesting that a dysproteinemia rather than a deficiency of synthesis is responsible for the child's coagulopathy.

Blood Coagulation Disorders↗
PubMed1984

Spinal cord contains neurotrophic activity for spinal nerve sensory neurons. Late developmental appearance of a survival factor distinct from nerve growth factor.

Several tissues of the developing chick embryo have been reported to contain neurotrophic activity which can sustain the survival of sensory neurons maintained in culture. In a previous study, however, we noted that such nerve growth promoting activity was exceptionally low, if not absent, from extracts of spinal cord from chick embryos of up to 16 days incubation. Since then the combined results from a number of tissue culture studies have suggested that the central nervous system may be the source of a neurotrophic growth factor essential during the late development of sensory neurons. We have therefore carried out an extended range study of the neurotrophic properties of avian spinal cord. Extracts of spinal cord tissue prepared from chicks at stages between the last wk of embryogenesis and 12 wks after hatching were tested for their ability to promote survival and neurite outgrowth from both explant and dissociated neuron-enriched cultures of dorsal root, trigeminal, nodose and paravertebral chain sympathetic ganglia from chick embryos between 8 and 16 days old. We conclude from our results that spinal cord is a potent source of neurotrophic activity for sensory neurons, although this activity appears relatively late in development of the spinal cord. The predominant ontogenic increase in spinal cord neurotrophic activity was seen to occur during the first week after hatching. Sensory neurons from both spinal and cranial nerve ganglia were sustained in culture by spinal cord extracts, whereas sympathetic neurons did not respond. Neurons from older sensory ganglia (12-16 day old embryos) were much more responsive than similar neurons from young embryos (8 day).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Continuous sulfa prophylaxis for urinary tract infection in renal transplant recipients.

During a 12 to 25 month follow-up period, 252 renal transplant recipients maintained with continuous sulfa prophylaxis were observed for evidence of bacteriuria. Although symptoms were rare, positive cultures were obtained in 6 percent of the patients who responded to conventional antibiotic outpatient therapy. Compared with sulfisoxazole, trimethoprim-sulfamethoxazole led to slightly fewer infections, especially with gram-negative organisms. Toxicity from sulfa was minimal and occasional leukopenia reversed by temporarily withholding azathioprine. Continuous sulfa prophylaxis in renal transplant patients is therefore safe and effective in minimizing the incidence of urinary tract infection, as well as other opportunistic infections known to be treatable by sulfa agents.

Bacteriuria↗
PubMed1981

Phosphate ester groups in proteoglycans from bovine nasal cartilage.

1. Proteoglycan subunits isolated by standard procedures from bovine nasal cartilage, previously incubated in the presence of [32P]phosphate contain [32]-phosphate ester groups as a regular structural component. 2. Contamination of the proteoglycan subunit with 32P-labeled nucleic acids could be excluded by repeated cesium chloride density gradient centrifugation under associative and dissociative conditions, lanthanum chloride precipitation, gel filtration and by the resistance of the proteoglycan subunit associated 32P to phosphoric diester hydrolases. 3. The [32P]phosphate ester groups are associated to the chondroitin sulfate peptide fraction obtained by proteolytic digestion of the proteoglycan subunit molecule. Degradation of the chondroitin sulfate peptide by chondroitinase ABC resulted in a 32P-labelled oligosaccharide peptide fraction, that contains xylose, galactose, glucuronic acid and inorganic phosphate in a molar ratio 1 : 2 : 1 : 0.12. 4. 32P radioactivity is released as inorganic phosphate by treatment of the 32P-labelled oligosaccharide peptide with acid phosphatase or alkali.

Acid Phosphatase↗