Biomedical subjects

J Formanek

Publications and source records attributed to J Formanek.

4 recordsLinked to original sources

PubMed1997

Enhanced Butanol Production by Clostridium beijerinckii BA101 Grown in Semidefined P2 Medium Containing 6 Percent Maltodextrin or Glucose.

Dramatically elevated levels of butanol and acetone resulted in higher butanol and total solvent yields for hyperamylolytic Clostridium beijerinckii BA101 relative to the NCIMB 8052 parent strain grown in semidefined P2 medium containing either 6% glucose or STAR-DRI 5 maltodextrin. C. beijerinckii BA101 consistently produced on the order of 19 g of butanol per liter in 20-liter batch fermentations. This represents a greater than 100% increase in butanol concentration by the BA101 strain compared to the parent NCIMB 8052 strain. The kinetics of butanol production over time also indicate a more rapid rate of butanol production by BA101 in semidefined P2 medium containing glucose or maltodextrin. The lower levels of butyric and acetic acids produced over the course of the fermentation carried out by BA101 are consistent with an enhanced capacity for uptake and recycling of these acids. C. beijerinckii BA101 appears to more completely utilize carbohydrate compared to the 8052 strain. Carbon balance following fermentation by C. beijerinckii 8052 and BA101 indicates that sufficient carbon is available for the twofold increase in butanol concentration observed during BA101 fermentations. C. beijerinckii BA101 also has superior solvent production capacity during continuous culture fermentation in P2 medium containing 6% glucose. Volumetric solvent yields of 0.78 and 1.74 g/liter/h for BA101 and 0.34 and 1.17 g/liter/h for NCIMB 8052 were obtained at dilution rates of 0.05 and 0.20 h(sup-1), respectively. No drift towards acid synthesis (strain degeneration) was observed for up to 200 h (d = 0.05 h(sup-1)) and 100 h (d = 0.20 h(sup-1)).

Journal Article↗

PubMed1995

Neurotoxicity profile of supermethrin, a new pyrethroid insecticide.

The use of a standard two-tier neurotoxicity screening procedure in the context of risk assessment is exemplified. Testing of a new pyrethroid in rats addressed the following sequence of questions: Does the substance evoke neurotoxic symptoms in sublethal doses? Do these symptoms reflect a primary neurotropic action? What are the dynamic characteristics of injury, the clinical profile of effect, and the relative potency of the tested substance compared to similar compounds? - The testing protocol is an animal analogue of a systematic neurological and psychological examination in man. First tier tests (structured observation, motor activity measurement, simple neurological examination) were applied after the first dose, during repeated dosing phase and in the restitution phase. Facultative tests for the second-tier examination (motor activity pattern, learning/retention test, evoked potentials, dynamic motor performance) were selected on the basis of effects revealed by the first-tier testing. Supermethrin evoked acute neurotoxicity in sublethal doses, ranging from 1/30 to 1/15 of LD50. The clinical pattern was similar to other cyano-substituted pyrethroids. Behavioural inhibition was transient and complete tolerance to it developed after 4-week repeated dosing. No indications of long-lasting changes in neuronal excitability or in learning and memory processes were found. Ataxia and excitomotoric phenomena dominated both the acute and the subchronic picture. Marked and persistent motor disturbances, including symptoms of lower motoneuron injury, were limited to individual animals of the highest, near-lethal dose group (27 mg-kg-1). Compared to lambda-cyhalothrin, the effects of supermethrin were 2 to 3 times weaker, disappeared more rapidly, cumulated less, and had higher tendency to tolerance.

Animals↗

PubMed1969

Hallucinogen-tranquilizer interaction: its nature.

Study of the competition between hallucinogens and tranquilizers at cerebral synapses and on behavior in various species of animals indicates a continuum of effects from protection to dominance of tranquilizer toxicity as the dose of tranquilizer increases. Data on cat and monkey behavior, supplementing that on the rat, show that it is possible to arrive at a tranquilizer dose that can aggravate instead of protect, in accord with the competitive inhibitory nature of the interaction of hallucinogen and tranquilizer.

Animals↗

PubMedDate not supplied

The influence of a magnetic field on manganese transport into rat brain.

The aim of this study was to detect the effect of a magnetic field on manganese transport into rat brains. An experimental group of Female Wistar rats was given 0.48 mg Mn2+ per kg body weight intratracheally twice a week for 3 months and simultaneously exposed to a magnetic field: B = 10 mT, f = 50 Hz for 1 hr. Rats in one control group of rats received the same dose of manganese as the experimental group but were not exposed to the magnetic field. Rats in a second control group had neither exposure to manganese nor exposure to the magnetic field. After the last dose, all rats were sacrificed and their brains and other tissues were analyzed for manganese content. The results indicated that the magnetic field had a positive effect on increasing the manganese content in the brains of rats in the experimental group relative to those of the control groups. Visual evoked potentials (VEP) measured at the end of the exposure periods on randomly selected experimental and control rats showed a shortened but not statistically significant latency of the P1 peak of VEP in rats that had been exposed to both factors but not in control rats.

Animals↗