The effects of speed, frequency, and load on measured hand forces for a floor to knuckle lifting task.

The purpose of this study was to describe and quantify measured hand forces during floor to knuckle lifting of various loads. Hand forces of five subjects were measured with a strain gauge apparatus for normal and fast speeds of lifting at 1, 4, and 8 l/min. The pattern of hand force over time exhibited peaks in force in the shape of a spike for all fast lifts, indicating that subjects did not lift smoothly. For normal speed of lift, only one of the five subjects executed some lifts smoothly, indicating that it may be possible to lift smoothly, but most lifters probably do not. Peaks of horizontal and vertical components of hand force were tabulated by speed of lift, frequency, and load.     

Influence of 2-acetylaminofluorene (2-AAF) on biotransformation and lipid peroxidation in salivary glands and liver from male rats

Salivary glands proved to be active in biotransformation. In microsomes of rat salivary glands 7-ethoxyresorufin O-deethylation (EROD) and 7-pentoxyresorufin O-depentylation (PEROD) were detectable, but with much lower activities than in the liver. Beside the well-known induction of EROD or PEROD in the liver by beta-naphthoflavone (BNF) or phenobarbital (PB), respectively, a marked rise in EROD rate of salivary glands was observed after BNF treatment. Administration of 2-AAF caused an increase in EROD rates in liver microsomes, but a decrease in microsomes of salivary glands. This decrease in EROD rate was accompanied by selective cytotoxic damages in the convoluted granulated tubules of the submandibular glands. No cytotoxic damage occurred in the submandibular glands after a combined administration of the inducer BNF and 2-AAF. This indicates relations between these toxic effects of 2-AAF and changes of 2-AAF-metabolism in BNF-induced rats, maybe in the liver and/or in the submandibular glands themselves.     

Prevention of 2-acetylaminofluorene-induced extrahepatic short-term effects by 3-methylcholanthrene

It is well known that simultaneous application of polycyclic carcinogenic hydrocarbons, especially 3-methylcholanthrene (MC) inhibits or prevents tumorigenesis induced by carcinogenic aromatic amines or azo dyes. Short-term tests showed a mitogenic effect upon adrenal cortex 48 hours following a single dose of 2-acetylaminofluorene (AAF) among other carcinogenic substances. 6 mg/kg body weight given simultaneously prevent the proliferative response of the adrenals by AAF (60 mg/kg b.w.) in male Sprague-Dawley rats. These different effects can be assumed to depend on the production of carcinogenic derivatives or their non-production. Therefore, the positive adrenal reaction by other substances tested is probably also provoked by carcinogenic compounds. The lack of responsiveness by MC may reflect a fundamental change of AAF metabolism. The mode of action is unknown. Possible explanations are discussed.     

REACTION OF LENTIL PROTEINASE INHIBITORS WITH HUMAN AND BOVINE TRYPSIN AND CHYMOTRYPSIN1

The two main trypsin-chymotrypsin isoinhibitors previously purified from lentils (Lens culinaris Medik.), LCI-1 and LCI-4, inhibited one mol of human trypsin (1.05 and 1.00), more than one mol of bovine trypsin (1.53 and 1.38) and human chymotrypsin (1.70 and 1.43) as well as less than one mol of bovine chymotrypsin (0.62 and 0.54, respectively) per mol of inhibitor. Complex formation, together with chemical and enzymatic modification studies, showed that they were Bowman-Birk inhibitors with two independent reactive sites. One of these sites, mainly reacting with trypsin, contained arginine and bound tightly to bovine trypsin, less tightly to human trypsin and loosely to human chymotrypsin. The other reactive site, preferring chymotrypsin, contained tyrosine and bound tightly to human chymotrypsin, less tightly to bovine chymotrypsin and loosely to bovine trypsin. The amounts of bound enzyme exceeding one mol per mol of inhibitor reacted with the “wrong” sites: bovine trypsin with the chymotrypsin-reactive and human chymotrypsin with the trypsin-reactive one. The much higher inhibition of human chymotrypsin compared to that of bovine chymotrypsin resulted from a combination of two effects: the additional binding of human chymotrypsin at the “wrong” reactive site and the weak binding of the bovine chymotrypsin.     

Investigating Alkylated Prodigiosenes and Their Cu(II)-Dependent Biological Activity: Interactions with DNA,Antimicrobial and Photoinduced Anticancer Activity

Prodigiosenes are a family of red pigments with versatile biological activity. Their tripyrrolic core structure has been modified many times in order to manipulate the spectrum of activity. We have been looking systematically at prodigiosenes substituted at the C ring with alkyl chains of different lengths, in order to assess the relevance of this substituent in a context that has not been investigated before for these derivatives: Cu(II) complexation, DNA binding, self-activated DNA cleavage, photoinduced cytotoxicity and antimicrobial activity. Our results indicate that the hydrophobic substituent has a clear influence on the different aspects of their biological activity. The cytotoxicity study of the Cu(II) complexes of these prodigiosenes shows that they exhibit a strong cytotoxic effect towards the tested tumor cell lines. The Cu(II) complex of a prodigiosene lacking any alkyl chain excelled in its photoinduced anticancer activity, thus demonstrating the potential of prodigiosenes and their metal complexes for an application in photodynamic therapy (PDT). Two derivatives along with their Cu(II) complexes showed also antimicrobial activity against Staphylococcus aureus strains.