PubMed Health⌕ Search

Biomedical subjects

C F Albrecht

Publications and source records attributed to C F Albrecht.

At least 19 recordsLinked to original sources
PubMed2002

Can contrast enhanced MRI predict the response of Graves' ophthalmopathy to orbital radiotherapy?

The purpose of this study was to try to determine by means of contrast-enhanced MRI, a subset of patients with Graves' ophthalmopathy who will not respond to orbital radiotherapy. 54 patients with Graves' ophthalmopathy were treated with orbital radiotherapy (10 x 2 Gy) and symptom relief was recorded. MRI examinations prior to radiotherapy were retrospectively evaluated for enlargement, contrast enhancement and fibrotic changes in extraocular muscles and surrounding soft tissue. Imaging data were correlated with clinical features and response. Symptom relief was observed in 61% of patients but this could not be predicted by any of the MRI signs investigated. However, there is a trend for a better treatment reponse in patients who show contrast enhancement of extraocular muscles prior to orbital radiotherapy (p=0.08). MRI could not adequately predict the efficacy of orbital radiotherapy in this group of patients. Clinical assessment of disease activity is still the most reliable method.

Adolescent↗
PubMed2000

Chemical analyses of Ukrain, a semi-synthetic Chelidonium majus alkaloid derivative, fail to confirm its trimeric structure.

Ukrain has been described as a semi-synthetic Chelidonium majus alkaloid derivative, consisting of three chelidonine alkaloids combined to triaziridide. We found the actions of Ukrain to be similar to the Chelidonium alkaloids it is prepared from, and therefore became concerned about its chemical integrity. Chemical analyses of Ukrain by thin layer chromatography, high-performance liquid chromatography and liquid chromatography-mass spectrometry was inconsistent with the proposed trimeric structure and demonstrated that at least some commercial preparations of Ukrain consist of a mixture of C. majus alkaloids (including chelidonine).

Alkaloids↗
PubMed2000

Bioactive alkaloids from Brunsvigia radulosa.

A phytochemical investigation of the bulbs of Brunsvigia radulosa yielded the new alkaloid 1-O-acetylnorpluviine, together with the known structures 1-epideacetylbowdensine, crinamine, crinine, hamayne, lycorine, anhydrolycorin-6-one and sternbergine. All structures were established by spectroscopic evidence. Some of the 13C assignments which were reported for crinamine and hamayne were corrected by means of 2D NMR techniques. In order to provide a further structure for biological testing, crinamine was converted to apohaemanthamine. The alkaloids were tested for activity against two strains of cultured Plasmodium falciparum and for cytotoxicity with BL6 mouse melanoma cells.

Alkaloids↗
PubMed1999

Erythropoietin production in anemia associated with experimental cancer.

Serum erythropoietin (EPO) concentrations reportedly are depressed in patients with chronic disorders such as cancer, rheumatoid arthritis, and acquired immunodeficiency syndrome. We evaluated serum EPO levels in mice with tumors and found that the EPO response was appropriate for the associated anemia during the major part of the disease process. The levels of the hormone increased as the anemia worsened in association with progression of the disease. The increased EPO levels were comparable to those of controls with a similar degree of experimentally induced anemia. Only during the terminal stages of cancer, when the animals were severely cachectic, were serum EPO concentrations lower than in controls with a similar degree of anemia. These findings suggest that a blunted EPO response in experimental cancer occurs only in association with advanced disease.

Anemia, Hemolytic↗
PubMed1999

Effect of rooperol on collagen synthesis and cell growth.

The effect of rooperol on type I collagen synthesis in normal skin and lung fibroblasts and cell growth in normal and transformed fibroblasts was investigated. Low concentrations of rooperol selectively inhibited the growth of transformed cells while stimulating collagen synthesis in normal fibroblasts. Elevated collagen synthesis and deposition could impede tumour cell invasion and metastasis, implying that rooperol may be useful as an antimetastatic agent in the treatment of cancer.

Catechols↗
PubMed1998

Triterpenoid saponins from Becium grandiflorum var. obovatum.

Two new triterpenoid saponins, beciumecine 1 and 2, were isolated from the root bark of Becium grandiflorum var. obovatum and their structures established as 3-O-(beta-D-glucopyranosyl) terminolic acid 28-O-beta-D-apiofuranosyl(1-3)-[alpha-L-rhamnopyranosyl (1-3)-beta-D-xylopyranosyl(1-4)]-alpha-L-rhamnopyranosyl (1-2)-alpha-L-arabinopyranoside and 3-O-(beta-D-glucopyranosyl) 24-hydroxyterminolic acid 28-O-alpha-L-rhamnopyranosyl(1-3)-beta-D-xylopyranosyl(1-4)-alpha-L- rhamnopyranosyl(1-2)-alpha-L-arabinopyranoside, respectively.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Cytotoxic and antimalarial alkaloids from Brunsvigia littoralis.

Four known alkaloids, lycorine (1), 1,2-di-O-acetyllycorine (2), ambelline (3), and crinine (4) were isolated from the bulbs of Brunsvigia littoralis (Amaryllidaceae). 1H- and 13C-NMR spectra of 2 were completely assigned by means of 1D- and 2D-NMR techniques. The alkaloids (1-4) together with the synthesised 11-O-acetylambelline (3a) and 3-O-acetylcrinine (4a) were tested for antimalarial activity with two strains of cultured Plasmodium falciparum and for cytotoxicity with BL6 mouse melanoma cells. Structures 1 and 2 exhibited both antimalarial and cytotoxic activity.

Alkaloids↗
PubMed1997

A randomised placebo-controlled trial of the efficacy of beta-sitosterol and its glucoside as adjuvants in the treatment of pulmonary tuberculosis.

OBJECTIVE: To evaluate the adjuvant effect of beta-sitosterol and its glucoside in the treatment of culture proven pulmonary tuberculosis (PTB). DESIGN: A blinded randomised placebo-controlled trial in culture proven drug sensitive PTB. Patients were hospitalised for the duration of treatment and evaluated at monthly intervals with regard to sputum culture positivity, chest radiography, weight gain, Mantoux test response, routine haematology and liver functions. STATISTICAL EVALUATION: General linear models for repeated measures (SAS GLM package) compared the interaction effects, group effects and time effects of findings in 19 patients receiving sitosterols with those in 18 patients receiving a placebo (talcum powder). Absolute values and change from baseline values were evaluated, although only the latter are reported. RESULTS: Weight gain was significantly greater in the sitosterol group (mean weight gain 8.9 kg) than the placebo group (mean gain 6.1 kg) (P = 0.0023 group effects; P = 0.0001 for time effects). Speed of achieving culture negativity, radiological improvement and induration on Mantoux testing was similar in the two groups. Change in lymphocyte counts from baseline was significantly higher in the sitosterol group (P = 0.0001 and P = 0.0001 for group and time effects) as was the increase in eosinophil counts (P = 0.0001 and P = 0.0137 for group and time effects). CONCLUSION: The study has shown significantly improved weight gain and higher lymphocyte and eosinophil counts in PTB patients receiving sitosterols in addition to an efficacious antituberculosis regimen. Sitosterols and their possible mode of action should now be evaluated in larger numbers of tuberculosis patients and in diseases with a similar immunopathogenesis.

Adjuvants, Immunologic↗
PubMed1996

beta-Sitosterol and beta-sitosterol glucoside stimulate human peripheral blood lymphocyte proliferation: implications for their use as an immunomodulatory vitamin combination.

The phytosterols, beta-sitosterol (BSS), and its glucoside (BSSG) enhance the in vitro proliferative response of T-cells stimulated by sub-optimal concentrations of phytohaemagglutinin (PHA) several fold at extremely low concentrations (femtogram level). A 100:1 (mass:mass) ratio of BSS:BSSG (termed essential sterolin formulation, ESF) showed higher stimulation than the individual sterols at the same concentration. In vivo activity of ESF was also demonstrated when volunteers ingested ESF for 4 weeks. Proliferation of their T-cells, stimulated maximally with PHA, was significantly enhanced (20-920%) when compared to baseline values. In vitro, ESF (1 microgram.ml) was able to significantly enhance the expression of CD25 and HLA-Dr activation antigens on T-cells and increased the secretion, into the medium, of IL-2 and gamma interferon. NK-cell activity was also increased by BSS and BSSG alone, but with EST a higher activity was always found at different effector:target ratios (100:1 12:1).

Adjuvants, Immunologic↗
PubMed1996

Pharmacokinetic behaviour and cardiovascular effects of intravenously administered hypoxoside and rooperol.

This study concerns the pharmacokinetic behaviour and cardiovascular effects of rapid infusions of hypoxoside (CAS 83643-94-1) and rooperol (CAS 83644-00-2) in anaesthetised Chacma baboons. Institutional approval was obtained and animal care conformed to international guidelines. Hypoxoside (500 mg) and rooperol (240 mg) dissolved in isotonic saline were infused during 15 min. Concentration-time data from high performance liquid chromatography of arterial blood samples were subjected to non-linear curve-fitting to obtain two-compartment mammillary pharmacokinetic models. Mean values were: [Table: see text] Hypoxoside was eliminated without significant metabolite formation and it revealed no cardiovascular effects. Rooperol was metabolized rapidly with formation of nine metabolites of which the major three were the diglucuronide, disulphate and mixed glucuronide sulphate. Rooperol caused moderate, transient increased cardiac output, stroke volume and vascular pressures without increased heart rate or filling pressures, suggestive of increased myocardial contractility probably allied to its catechol structure.

Alkynes↗
PubMed1995

Morphological characterisation of the cell-growth inhibitory activity of rooperol and pharmacokinetic aspects of hypoxoside as an oral prodrug for cancer therapy.

Hypoxoside is the major diglucoside isolated from the corms of the plant family Hypoxidaceae. It contains an unusual E-pent-1-en-4-yne 5-carbon bridging unit with two distal catechol groups to which the glucose moieties are attached. It is non-toxic for BL6 mouse melanoma cells in tissue culture on condition that the fetal calf serum in the medium is heat-inactivated for 1 hour at 56 degrees C in order to destroy endogenous beta-glucosidase activity. The latter catalyses hypoxoside conversion to its cytotoxic aglucone, rooperol, which, when tested as a pure chemical, caused 50% inhibition of BL6 melanoma cell growth at 10 micrograms/ml. Light and electron microscopy revealed that the cytotoxic effect of rooperol manifested as vacuolisation of the cytoplasm and formation of pores in the plasma membrane. Indications of apoptosis were also found. Pharmacokinetic studies on mice dosed intragastrically with hypoxoside showed that it was deconjugated by bacterial beta-glucosidase to form rooperol in the colon. Surprisingly, no hypoxoside or rooperol was detectable in the serum. Only phase II biotransformation products (sulphates and glucuronides) were present in the portal blood and bile. In contrast, however, in human serum after oral ingestion of hypoxoside, the metabolites can reach relatively high concentrations. Rooperol metabolites isolated from human urine were non-toxic for BL6 melanoma cells in culture up to a concentration of 200 micrograms/ml. In the presence of beta-glucuronidase, which released rooperol from the metabolites, 50% growth inhibition was achieved at a 75 micrograms/ml metabolite concentration. The supernatant of a human melanoma homogenate could also cause deconjugation of the metabolites to form rooperol.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkynes↗
PubMed1995

The pharmacokinetic behaviour of hypoxoside taken orally by patients with lung cancer in a phase I trial.

OBJECTIVE: To study the pharmacokinetic behaviour of hypoxoside taken orally by 24 patients with lung cancer. DESIGN: Randomised open study with three single doses of 1,600, 2,400 and 3,200 mg standardised Hypoxis plant extract (200 mg capsules) and a multiple-dose study on the first 6 patients taking 4 capsules 3 times daily for 11 days. PARTICIPANTS AND SETTING: Patients with histologically proven squamous, large-cell or adenocarcinoma were hospitalised at the Radiation Oncology Ward, Karl Bremer Hospital, Bellville, W. Cape. METHODS: Blood was drawn at regular intervals up to 75 hours after single doses and the concentrations of metabolites of the aglucone of hypoxoside, rooperol, were measured with a high-performance liquid chromatography method. For the multiple-dose study blood was drawn before the first dose each day. Concentration-time relationships were analysed according to a conventional single open-compartment model and also by using the NONMEM digital computer programme. RESULTS: Neither hypoxoside nor rooperol appear in circulation. This is due to complete phase II biotransformation to diglucuronide, disulphate and mixed glucuronide-sulphate metabolites, of which the latter is the major component. Considerable interpatient variation in concentration-time relationships was found in the single-dose studies. It was due to an active enterohepatic recirculation in some patients and a distinct lag phase in others together with zero-order rate of formation of rooperol in the colon. Computer modelling indicated a single open-compartment model in which the mass of the patient did not influence volume of distribution and clearance because formation of the metabolites is dependent on the metabolising capacity of the patient. However, the elimination of the metabolites follows first-order kinetics with half-lives ranging from 50 hours for the major metabolite to 20 hours for the two minor metabolites. Multiple-dose studies also showed large interpatient variation. CONCLUSION: In order to reach metabolite levels near 100 micrograms/ml, which have been shown to be tumouricidal after enzymatic deconjugation to rooperol, maintenance doses need to be individualised for each patient. For most patients, however, a daily dose of 2,400 mg was sufficient.

Adult↗
PubMed1995

A phase I trial of hypoxoside as an oral prodrug for cancer therapy--absence of toxicity.

OBJECTIVE: To assess the toxicity of hypoxoside taken orally by 24 patients with lung cancer. DESIGN: Open study with patients taking 1,200-3,200 mg standardised Hypoxis plant extract (200 mg capsules) per day divided in 3 doses in order to maintain metabolite blood levels near 100 micrograms/ml. PARTICIPANTS AND SETTING: Patients with histologically proven squamous, large-cell or adenocarcinoma were hospitalised initially at the radiation oncology ward, Karl Bremer Hospital, Bellville, W. Cape. Thereafter they returned every 2 weeks for full clinical examinations. METHODS: Routine biochemical and haematological measurements were done. Patients underwent regular full clinical examinations including radiographs and computed tomography scanning according to the discretion of the principal investigator. RESULTS: Nineteen patients on hypoxoside therapy survived for an average of 4 months with progression of their primary tumours and metastases, while 5 survived for more than a year. One of them survived for 5 years and histological examination of the primary lesion showed absence of cancer. No toxic effects, in clinical examinations or biochemical or haematological measurements, were found that could be ascribed to the ingestion of hypoxoside. Only one occasion of possible drug intolerance, with anxiety, nausea, vomiting and diarrhoea, was noted. CONCLUSION: The absence of toxicity warrants further investigation of hypoxoside as an oral prodrug, especially in patients with slow-growing necrotising tumours that are inoperable and have high concentrations of beta-glucuronidase and sulphatase as well as a high sensitivity for rooperol.

Adenocarcinoma↗
PubMed1994

Studies on hypoxoside and rooperol analogues from Hypoxis rooperi and Hypoxis latifolia and their biotransformation in man by using high-performance liquid chromatography with in-line sorption enrichment and diode-array detection.

Methanol extracts of the corms of Hypoxis rooperi and H. latifolia were studied for their hypoxoside content by an in-line sorption enrichment HPLC technique [Kruger et al., J. Chromatogr., 612 (1993) 191]. Hypoxoside is the trivial name for (E)-1,5-bis(3'-hydroxy-4'-O-beta-D-glucopyranosyl-phenyl) pent-1-en-4-yne and rooperol the aglucone obtained from beta-glucosidase treatment. Hypoxoside and rooperol analogues containing 4, 3 and 2 hydroxyl groups resolved as separate peaks with the proportion of the latter two markedly higher in H. latifolia than in H. rooperi. After oral ingestion of hypoxoside by humans, no hypoxoside or rooperol appeared in the serum. Only rooperol was present in the faeces. The serum and urine contained at least three phase II metabolite peaks. Selective enzyme hydrolysis showed that they represent the diglucuronide, disulfate and glucuronide-sulfate conjugates of all three rooperol analogues.

Alkynes↗
PubMed1994

beta-Glucosidase activity in fetal bovine serum renders the plant glucoside, hypoxoside, cytotoxic toward B16-F10-BL-6 mouse melanoma cells.

By using p-nitrophenyl-beta-D-glucopyranoside as substrate, beta-glucosidase activity was observed in fetal bovine serum (FBS). This activity could be inhibited by heat inactivation of the serum. Gel chromatography of FBS indicated the presence of beta-glucosidase activity with an apparent molecular mass of 29 kDa. In McCoy's 5A medium supplemented with non-heat inactivated FBS, the diglucoside hypoxoside ([E]-1,5-bis[4'beta-D-glucopyranosyloxy-3'-hydroxyphenyl]pent-4-en - 1-yne) showed cytotoxicity toward B16-F10-BL-6 mouse melanoma cells. In incubations where the media were supplemented with FBS previously heat inactivated at 56 degrees C for 1 h or more, no cytotoxicity was observed in the presence of hypoxoside. The aglucone of hypoxoside, rooperol ([E]-1,5-bis[3',4'-dihydroxyphenyl]pent-4-en-1-yne), showed cytotoxicity regardless of whether the serum was heat inactivated or not. The kinetics of the heat inactivation of the beta-glucosidase activity in FBS coincided with the loss of apparent cytotoxicity of hypoxoside. High performance liquid chromatography analysis showed that rooperol could be generated by incubation of hypoxoside in non-heat inactivated FBS, but that this ability was lost in serum that was heat inactivated for 1 h or longer. Newborn bovine serum did not contain any beta-glucosidase activity whereas it was found in three different commercial sources of FBS. This observation is of practical importance because conventional heat inactivation of FBS at 56 degrees C for 30 min was not sufficient to inactivate the beta-glucosidase activity completely.

Alkynes↗
PubMed1993

Use of guanidine hydrochloride and ammonium sulfate in comprehensive in-line sorption enrichment of xenobiotics in biological fluids by high-performance liquid chromatography.

A novel approach has been developed for direct injection of physiological fluids on an in-line extraction pre-column followed by column switching in order to introduce the adsorbed xenobiotic onto the analytical column. The physiological fluid is pre-treated with guanidinium solution in water (200 microliters of fluid plus 300 microliters of a reagent containing 8.05 M guanidinium and 1.02 M ammonium sulfate) in order to denature protein binding sites and to serve as a universal solvent for a divergent range of polar to non-polar xenobiotics in a hydrophilic medium. A 0.5 M ammonium sulfate solution (500 microliters) is used as a pre- and post-flush reagent for the extraction pre-column (30 mm x 2.1 mm I.D.). The pre-flush reagent prepares the sorbent environment of the C18 pre-column for the hydrophobic retention of analytes. The post-flush reagent flushes non-retained sample proteins and salts to waste prior to switching the pre-column in-line with the analytical column. Universal chromatographic conditions for the analytical phase allows elution of a range of polar to non-polar xenobiotics within 20 min from an end-capped C8 silica analytical column (250 mm x 4.6 mm I.D.). This is effected by a linear gradient from a binary system consisting of solvent A (0.05 M KH2PO4) and solvent B (acetonitrile-isopropanol, 80:20, v/v).

Ammonium Sulfate↗
PubMed1989

Detection of 3-hydroxy-3-methyloxindole in human urine.

During routine toxicological screening of urine for possible drug overdose, using two-dimensional thin-layer chromatography, an unknown substance was periodically detected that could not be related to any known drug. The substance was mass-isolated from the urine of a schizophrenic patient, who excreted it prolifically and it was chemically identified as 3-hydroxy-3-methyloxindole by mass spectrometry and 1H- and 13C-NMR. The structure was confirmed by synthesis through methylation of isatin. This is the first report associating 3-hydroxy-3-methyloxindole with human biochemistry. It is thought that this substance is an in vivo oxidation product of 3-methylindole which is a metabolic product of tryptophan, produced by bacteria in the colon.

Chromatography, High Pressure Liquid↗