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Biomedical subjects

G G Habermehl

Publications and source records attributed to G G Habermehl.

At least 19 recordsLinked to original sources
PubMed2001

[A modification of the in ovo-method for the determination of the antihemorrhagic activity of plant extracts].

Up to now there has been only a method available for testing the antihaemorrhagic activity of plant extracts, in which chicken embryos had to be transferred to a special container on the fifth day of incubation. Furthermore, the test could not be conducted on the extraembryonal circulatory system until two days later. In the test method described here the embryos remain inside the egg. After removal of the eggshell through the air cell and removal of the inner shell membrane, direct access to the extraembryonal circulatory system is possible, minimising external influences on the test system. This represents a dramatic simplification in technique and permits testing already on the fourth day of incubation. The application of this method to determine the antihaemorrhagic properties of samples has the advantage of permitting the simple and quick production of haemorrhages by snake venom on the yolk sac circulatory system.

Animals↗
PubMed2000

Eleganoside-A, B and C from Pseudocalymma elegans, a native of Brazil.

The toxic methanol-soluble part of Pseudocalymma elegans (leaves), a native of Brazil, yielded three new iridoidglucosides (1a-3a) as their acetate-derivatives (1-3) named eleganoside-A (1a), B (2a) and C (3a) which have been characterized with the aid of spectroscopic techniques, including 2D NMR.

Glucosides↗
PubMed1999

Spatial structures of the bradykinin potentiating peptide F from Agkistrodon piscivorus piscivoris venom.

Bradykinin potentiating peptides usually show two different activities, potentiation of bradykinin and inhibition of angiotensin converting enzyme (ACE). Exceptions of this rule have been found suggesting that both effects occur independently. This study of peptide F by means of NMR spectroscopy shows clearly two different main conformations of the molecule. These different conformations may be the reason for the different activities.

Agkistrodon↗
PubMed1998

[Effects of calcinogenic plants--qualitative and quantitative evaluation].

Different research methods demonstrated the presence of variable quantities of Vitamin D as well as its metabolites in calcinogenic plants. Most of the experiments indicated that the active component most probably should be the metabolite 1,25 (OH)2D3 linked as a glycoside. By this research it was achieved to evaluate the presence of elements with Vitamin D-like activity in the calcinogenic plants Solanum malacoxylon, Cestrum diurnum, Trisetum flavescens and Nierembergia veitchii by testing different extracts of the above plants by oral application to rachitic chicks within the research model "Strontium added Alimentation". After the oral administration of the extracts, the serum was analysed to determine the level of the elements calcium, phosphorus and alkaline phosphatase. The results gained with chicks demonstrated the presence of substances with Vitamin D-like activity in the 4 plants. Solanum malacoxylon and Cestrum diurnum as well contained substances of hydrosoluble character with elevated activity which was indicated by the significant high levels of calcium and phosphorus combined with a reduced activity of the alkaline phosphatase. This indicated the presence of 1,25 (OH)2D3 in both plants. The hydrosoluble character of the active substance in both plants is most probably explained as a compound of the metabolite 1,25 (OH)2D3, combined as a glycoside in the position O-25 of the molecule. Nierembergia veitchii and Trisetum flavescens contained only minor concentration of elements with hydrosoluble characteristics. The results of the 4 analysed plants were evaluated quantitatively as follows: Solanum malycoxylon--82,800 IU of Vitamin D/kg, Cestrum diurnum--63,200 IU of Vitamin D/kg, Nierembergia veitchii--16,400 IU/kg and Trisetum flavescens 12,000 Vitamin D IU/kg. All concentrations are calcinogenic.

Animal Feed↗
PubMed1996

Isolation and characterization of a bradykinin potentiating peptide (BPP-S) isolated from Scaptocosa raptoria venom.

Venom of the spider Scaptocosa raptoria was fractionated by chromatography on Sephadex G-10 followed by HPLC, and a bradykinin potentiating peptide, BPP-S, was obtained in pure form. The amino acid sequence of this undecapeptide is presented. Peptide BPP-S significantly potentiates the effects of bradykinin on smooth muscle, and inhibits the angiotensin-converting enzyme (ACE) in vitro.

Amino Acid Sequence↗
PubMed1995

Structure and effects of a kinin potentiating fraction F (AppF) isolated from Agkistrodon piscivorus piscivorus venom.

The contractile action of bradykinin on isolated smooth muscles is known to be potentiated by special peptides isolated from snake venoms and other animal sources. A fraction F (AppF) has been derived from Agkistrodon piscivorus piscivorus venom. This fraction does not increase the depressor effect of bradykinin n blood pressure, potentiates the action of bradykinin on isolated guinea-pig ileum and prolongs the duration of relaxation in isolated rat duodenum. This fraction was able to inhibit the conversion of angiotensin I to angiotensin II in vitro. The primary structure of this decapeptide is given.

Angiotensin I↗
PubMed1994

Poisonous plants of Brazil.

Poisonous plants are a serious problem for cattle breeding in Latin America. Owing to the extensive pastural agriculture it is not possible to exterminate such plants. Apart from the considerable financial loss to individual farmers and the national economy owing to dead animals, there is the important question of how far the meat and milk of chronically poisoned animals are a health risk for humans. The toxins of the most important toxic plants from Brazil are described.

Animals↗
PubMed1994

Severe ciguatera poisoning in Madagascar: a case report.

In a single outbreak on the East coast of Madagascar, more than 500 people, 98 of whom died, were poisoned by the flesh of a shark, Carcharhinus amboinensis. From clinical symptoms it can be concluded that this poisoning is due to ciguatera toxins. It is the first case of a severe outbreak caused by a shark, and it is the first case with a mortality rate of 20%.

Animals↗
PubMed1992

Antivenom and biological effects of ar-turmerone isolated from Curcuma longa (Zingiberaceae)

A potent antivenom against snakebite was isolated from Curcuma longa, a plant commonly used in traditional Brazilian medicine. The fraction consisting of ar-turmerone neutralized both the hemorrhagic activity present in Bothrops jararaca venom, and the lethal effect of Crotalus durissus terrificus venom in mice. Immunological studies demonstrated that this fraction also inhibited the proliferation and the natural killer activity of human lymphocytes.

Animals↗
PubMed1992

Isolation of a high-molecular mass glycoprotein from culture supernatant of an arthritogenic strain of the bacteria Erysipelothrix rhusiopathiae reacting with "inductive" monoclonal antibodies derived from rats with erysipelas polyarthritis.

A glycoprotein exhibiting a relative molecular mass of about 1000 kDa was purified to homogeneity from culture supernatant of arthritogenic bacteria (Erysipelothrix rhusiopathiae, strain T28) by ultrafiltration, ammonium sulfate precipitation, molecular mass exclusion, and ion exchange chromatography. Fractions obtained were analysed for their antigenic content by an enzyme linked immunosorbent assay (ELISA) using rabbit immune serum raised against this strain of Erysipelothrix rhusiopathiae. Distinct monoclonal antibodies obtained from rats suffering from erysipelas polyarthritis display a unique property by inducing very efficiently protective and regulatory mechanisms while being unable to generate classical "passive immunity". These "inductive" monoclonal antibodies recognize most likely linear epitopes on the purified glycoprotein. This makes it a prime source for analysing the target structure of these in vivo "inductive" antibodies.

Animals↗
PubMed1992

[Calcinogenic plants and the incubation effect of rumen fluid].

This paper describes incubation effects of rumen fluid on aqueous extracts of Trisetum flavescens, Solanum malacoxylon, Nierembergia veitchii, and Cestrum laevigatum. Investigation was performed by the rachitic chicken test, parameters determined were the serum levels of Ca, P, and alkaline phosphatase. Extracts of S. malacoxylon, and C. diurnum as well as 1,25(OH)2-VitD3-25-O-glucoside gave (without incubation) an increased activity, while with incubation a small additional effects could be observed. The extracts of T. flavescens and N. veitchii did not show any alteration with or without incubation. Comparable effects were obtained with 1,25(OH)2VitD3-1-O-glucoside, as well as 1,25(OH)2VitD3-3-O-glucoside.

Alkaline Phosphatase↗
PubMed1991

Evidence for superoxide dismutase and catalase in mollicutes and release of reactive oxygen species.

The presence of superoxide dismutase was demonstrated in 21 strains of mollicutes, including achuloplasmas, mycoplasmas and ureaplasmas. Additionally, catalase activities were demonstrated in nearly 50% of the cell lysates, whereas no peroxide activities were detectable. The production of O2- and H2O2 with glucose as substrate was demonstrated for 8 strains of 10 strains tested. Anaerobic mycoplasmas showed the highest amount of radical production, whereas superoxide dismutase and catalase activities were in the range of activities estimated for aerobic mollicutes. Some pathogenic strains additionally released compounds into the culture medium, which stimulated O2- production by PMNs.

Aerobiosis↗
PubMed1990

Evidence for superoxide dismutase and catalase in mollicutes and release of reactive oxygen species.

The presence of superoxide dismutase was demonstrated in 21 strains of mollicutes, including achuloplasmas, mycoplasmas, and ureaplasmas. No superoxide dismutase activities or only traces were detectable in fresh prepared cell lysates, whereas activities were evident after dialysis of the cell lysates. A further increase in superoxide dismutase activities was observed after the cell lysates were heated to 65 degrees C for 30 s. This might be due to the destruction of enzymatic reactions interfering with the activity tests. Additionally, catalase activities were demonstrated in nearly 50% of the cell lysates, whereas no peroxidase activities were detectable. The production of O2- and H2O2 with glucose as substrate was demonstrated for 8 of 10 strains tested. No correlation to the pathogenicities of the strains was indicated. Anaerobic mycoplasmas showed the highest amount of radical production, whereas superoxide dismutase and catalase activities were in the range of activities estimated for aerobic mollicutes.

Acholeplasma↗
PubMed1990

Interleukin 1-alpha and tumor necrosis factor-alpha induce oxygen radical production in mesangial cells.

Adherent human mesangial cells (HMC) were unable to phagocytose serum-treated zymosan (STZ), nevertheless this stimulus (1 mg/ml) induced a marked immediate increase of H2O2 and O2- release at a rate of 3.15 +/- 0.35 and 3.40 +/- 0.12 nmol/10(6) HMC/hr, respectively. Zymosan alone resulted in no release of either H2O2 or O2-. Phorbol myristate acetate (PMA, 2 X 10(-6) M) had only marginal effects on HMC leading to the generation of 0.273 +/- 0.014 nmol O2-/10(6) HMC/hr. After a lag period, human recombinant tumor necrosis factor-alpha (TNF-alpha) and human recombinant interleukin 1-alpha IL-1 alpha) both induced significant O2- production measured as SOD inhibitable reduction of cytochrome c, 5 X 10(-5) M, by adherent HMC for up to five hours, the maximum rates being 3.04 +/- 0.08 and 3.2 +/- 0.08 nmol/10(6) HMC/hr for IL-1 alpha and TNF-alpha, respectively. Significant O2- release was detectable at 0.625 ng/ml (37 pM) IL-1 alpha or 1 ng/ml (59 pM) TNF-alpha (P less than 0.05). Catalase inhibitable H2O2 production was also induced by IL-1 alpha and TNF-alpha in a dose dependent manner. Using scopoletin (40 nM) and 1 microM peroxidase we fluorimetrically measured 1.73 +/- 0.14 and 1.49 +/- 0.19 nmol H2O2/10(6) HMC/hr induced by IL-1 alpha (25 ng/ml) and TNF-alpha (20 ng/ml). Finally, we ascertained the type of radical species produced by HMC stimulated by cytokines employing ESR-spin-trapping with DMPO.2+ These results demonstrated that O2- was the primary radical species formed.(ABSTRACT TRUNCATED AT 250 WORDS)

Glomerular Mesangium↗
PubMed1990

Human fibroblasts release low amounts of reactive oxygen species in response to the potent phagocyte stimulants, serum-treated zymosan, N-formyl-methionyl-leucyl-phenylalanine, leukotriene B4 or 12-O-tetradecanoylphorbol 13-acetate.

Cell lines of human fibroblasts from primary cultures released reactive oxygen species, and displayed an increase in low-level chemiluminescence when stimulated with serum-treated zymosan, N-formyl-methionyl-leucyl-phenylalanine, leukotriene B4, or 12-O-tetradecanoylphorbol 13-acetate, all of which are known stimulants of respiratory burst in phagocytic cells. Non-serum-treated zymosan, interleukin-6, interleukin-2, interferon-gamma or complement factor C3b were ineffective. The primary radical species produced was O theta.2. Radical formation was continuous for up to 4 h, and it did not occur as an oxidative burst. The low level chemiluminescence probably arose from the excitation of carbonyl groups, since it remained unchanged in the presence of azide and 1,4-diazabicyclo[2.2.2]octane. While the release of reactive oxygen species in phagocytes has a function in defense mechanisms, the sustained production of such species in tissue cells may have a role in signaling mechanisms. The amounts of reactive oxygen species released by the fibroblasts upon stimulation with the stimulants mentioned above were low in comparison with the known stimulatory effects of cytokines [Meier et al. (1989) Biochem. J. 263, 539-545].

Electron Spin Resonance Spectroscopy↗