Galen's intermittent fever

In his comprehensive Oeuvre, Galen of Pergamon, who interpreted and perfected Hippocratic medicine, made many times and in various contexts mention of the intermittent fevers, among which malaria undoubtedly held a prominent position. The following article gives an outline of Galen's theoretical concept of this infectious disease, which was of utmost importance for the history of Italy. Galen describes three different types of intermittent fevers, of which, according to his theory of humoural pathology, each one is caused by a special humour with its respective qualities. Thus the quotidian fever is caused by phlegm, the tertian fever by the yellow bile and the quartan fever by the black bile. Apart from the three basic types of fever Galen describes a number of other mixed forms which can either be developed out of identical types or out of different ones. A mixture of a special kind is febris semitertiana: a continuous quotidian is accompanied by an intermittent tertian. It is the worst and most dangerous of these fevers. On the whole Galen's theory of malaria is a paradigm for his forming the reality of diseases on the basis of his pre-knowledge of humoural pathology into a closed system of theory.     

Necessitarianism and teleology in Aristotle's biology

In Aristotle's biological works, there is an apparent conflict between passages which seem to insist that only hypothetical necessity (anagk ex hypotheses) operates in the sublunary world, and passages in which some biological phenomena are explained as simply (hapls) necessary. Parallel to this textual problem lies the claim that explanations in terms of simple necessity render teleological explanations (in some of which Aristotle puts hypothetical necessity to use) superfluous. I argue that the textual conflict is only apparent, and that Aristotle's notion of coincidental sameness allows him to avoid the superfluity problem.     

The epiglottis in antiquity in medicine and philosophy

In Antiquity, the epiglottis and the related question whether drink enters the lung is a problem embracing both differently organized philosophical strategies and differently developed medical competences. Over the centuries, the history of a physiological question gradually turns into a debate where we find philosophers disagreeing with philosophers and physicians with physicians. A peculiar feature of this debate is that from a certain time on it involves a division between those who defend Plato's view on the subject and those who (philosophers as well as physicians) criticize it. Plato, Aristotle and Chrysippus, the Hippocratic authors and Erasistratus in the testimony of Aulus Gellius, Plutarch and indirectly also of Cicero, and then Galen and Macrobius have a special place in the development of this topic.     

Socio-Ecological Webs and Sites of Sociality:Levins' Strategy of Model Building Revisited

This essay extends Levins' 1966 analysis of modelbuilding in ecology and evolutionary biology. Amodel, as the product of modeling, might bevalued according to its correspondence to reality. Yet Levins' emphasis on provisionality and changeredirects attention to the processes ofmodeling, through which scientists select and generatetheir problems, define their categories, collect theirdata, compare competing models, and present theirfindings. I identify several points where decisionsare required that are not determined by nature. Thisinvites examination of the social considerationsmodelers are reacting to at the sites of sociality.Modelers must weave socio-ecological webs so thatthe models can be seen to represent their subjectmatter at the same time as the modelers secure thesupport of colleagues, collaborators and institutions,and enjoin others to act upon their conclusions. Notonly do theory justification and theory generationmerge, but the joint project becomes simultaneouslyphilosophical and sociological.     

Aristotle's study of the animal world: the case of the kobios and phucis

Aristotle was a remarkable observer of the living world. He made detailed observations on the anatomy and life history characteristics of many organisms as part of a larger study into the differentiae (diaphora) of groups of animals. This reexamination of Aristotle's observations of two small fishes is a study into the work or the way of being of particular organic wholes. As such, it is directed by three main objectives: to evaluate the accuracy of those observations Aristotle makes with regard to the kobios and phucis in the History of Animals, as well as to understand how he might have conducted his research; to determine whether aspects of those observations would ground more philosophical arguments; and to contribute to the understanding of the basic biology of these fishes. In so doing, this article also may introduce a new generation of biologists to the richness of Aristotle's biological observations and the questions that motivated them.     

T.H. Morgan,neither an epistemological empiricist nor a “Methodological” empiricist

T. H. Morgan (1866–1945), the founder of the Drosophila research group in genetics that established the chromosome theory of Mendelian inheritance, has been described as a radical empiricist in the historical literature. His empiricism, furthermore, is supposed to have prejudiced him against certain scientific conclusions. This paper aims to show two things: first, that the sense in which the term empiricism has been used by scholars is too weak to be illuminating. It is necessary to distinguish between empiricism as an epistemological position and the so-called methodological empiricism. I will argue that the way the latter has been presented cannot distinguish an empiricist methodology from a non-empiricist one. Second, I will show that T. H. Morgan was not an epistemological empiricist as this term is usually defined in philosophy. The reason is that he believed in the existence of genes as material entities when they were unobservable entities when they were unobservable entities introduced to account for the phenotypic ratios found in breeding experiments. These two points, of course, are interrelated. If we were to water down the meaning of empiricis, perhaps we could call Morgan an empiricist. But then we would also fail to distinguish empiricism from realism.     

Thermophilic and mesophilic bacteria in biofilms associated with corrosion in a heat exchanger

Biofilm development on AISI-1020 carbon steel coupons installed at the outlet of a heat exchanger was evaluated at the thirtieth and the sixtieth days of exposure. Water temperature varied between 41 and 60°C. The most probable number technique (MPN) was applied to quantify mesophilic and thermophilic species of aerobic, anaerobic, and sulphate-reducing bacteria (SRB) in planktonic and sessile phases. The results showed predominance of thermophilic aerobic bacteria in both phases, corresponding to 9.5±0.8×10⁶cells/ml in the planktonic phase. In biofilms, maximal aerobic cell concentration, 7.8±0.6×10⁸cells/cm2, was registered at the sixtieth day. An increase in the number of thermophilic anaerobic and SRB with elapsed time was also observed. The results obtained after 60 days were 5.8±0.4×10⁷ and 8.9±0.9×10⁴cells/cm² for anaerobic and sulphate-reducing bacteria, respectively. Scanning electron microscopy showed a varied composition of species in the biofilms and corrosion on the carbon steel surfaces after biofilm removal.     

Tetramethyl Rhodamine Methyl Ester (TMRM) is Suitable for Cytofluorometric Measurements of Mitochondrial Membrane Potential in Cells Treated with Digitonin

A new method for cytofluorometric analysis of mitochondrial membrane potential has been developed by using TMRM as a cationic, mitochondrial selective probe. The method is based on limited treatment of cultured cells with digitonin which permeabilises the plasma membrane and leaves mitochondria intact. The resulting signal of TMRM-stained cells thus represents only the probe accumulated in mitochondria. Fibroblasts and cybrids were used as a model cell systems and optimal conditions for digitonin treatment and staining by TMRM were described. The TMRM signal collapsed by valinomycin, KCN and antimycin A and FCCP titration was used to gradually lower and characterise the stability of . The method is suitable for sensitive measurement of in different types of cultured cells.     

Rethinking the role of theory in exploratory experimentation

To explain their role in discovery and contrast them with theory-driven research, philosophers of science have characterized exploratory experiments in terms of what they lack: namely, that they lack direction from what have been called “local theories” of the target system or object under investigation. I argue that this is incorrect: it’s not whether or not there is direction from a local theory that matters, but instead how such a theory is used to direct an experiment that matters. Appealing to contemporary exploratory experiments that involve the use of experimental techniques—specifically, examples where scientists explore the interaction of neural activity and human behavior by magnetically stimulating brains—I argue that local theories of a target system can inform auxiliary hypotheses in exploratory experiments, which direct these experiments. These examples illustrate how local theories can direct the exploration of target systems where researchers do not aim to evaluate these theories.     

Phase resetting associated with changes of burst shape

Based on our stochastic approach to phase resetting of an ensemble of oscillators, in this article we investigate two stimulation mechanisms which exhibit qualitatively different dynamical behaviour as compared with the stimulation mechanism analysed in a previous study. Both the old as well as one of the new stimulation mechanisms give rise to a characteristic desynchronization behaviour: A stimulus of a given (non-vanishing) intensity administered at a critical initial ensemble phase for a critical duration T _crit annihilates the ensemble's synchronized oscillation. When the stimulation duration exceeds T _crit a transition from type 1 resetting to type 0 resetting occurs. The second new stimulation mechanism does not cause a desynchronization which is connected with a phase singularity. Correspondingly this mechanism only leads to type 1 resetting. In contrast to the stimulation mechanism analysed in a previous study, both new stimulation mechanisms cause burst splitting. According to our results, in this case peak or onset detection algorithms are not able to reveal a correct estimate of the ensemble phase. Thus, whenever stimulation induced burst splitting occurs, phase-resetting curves determined by means of peak or onset detection may be nothing but artifacts. Therefore it is necessary to understand burst splitting in order to develop reliable phase detection algorithms, which are e.g. based on detecting bursts' centers of mass. Our results are important for experimentalists: Burst splitting is, for instance, well-known from tremor resetting experiments. Thus, it often turned out to be at least rather difficult to derive reliable phase-resetting curves from experimental data.     

Molecular cloning and sequence analyses of calcium/calmodulin- dependent protein kinase II from fetal and adult human brain – Sequence analyses of human brain calcium/calmodulin-dependent protein kinase II

The aims of this study were to characterize specific mRNAs and the expression pattern for isoforms of calcium/calmodulin-dependent protein kinase II (CaMKII) in the human brain. We cloned and sequenced the CaMKII and subunit cDNAs, and used them to study the CaMKII expression in human brain. Four distinct isoforms of CAMKII were isolated. Two of them were characterized as CaMKII and subunits. The other two showed similar nucleotide sequences, but one had a 33-bp insertion relative to the subunit, and the other had a 75-bp deletion relative to the subunit. These alterations are located within the variable regions. These two isoforms were characterized as CaMKII _B and _e. Northern blot analysis showed that a 4.4-kb messenger RNA for the isoform and a 3.9-kb messenger RNA for the isoform were expressed in both human fetal and adult brain to different degrees. The results indicate that CaMKII expression is developmentally regulated. The CaMKII isoform expression was confirmed in human fetal and adult brain using RT-PCR with specific primers, which flanked the CaMKII variable regions. The CaMKII , _B, , and _e isoforms were characterized in both human fetal and adult brain.     

Thermoregulation and thermal perception in the cold and heat before and after intermittent heat adaptation

Students wearing swim suits were exposed for 30 min to neutral room temperature (T_R=28C). During the following 60 min they were subjected to gradual decreases or increases of room temperature reaching 12C or 45C, respectively. Static thermal stimuli were applied to the palms of the right (38C) and left (25C) hands. Hands and feet of all subjects were thermally isolated at 22C ambient temperature. General thermal comfort (GTC), local thermal comfort (LTC), skin blood flow (which is proportional to heat transport index ) several body temperatures, oxygen-consumption , and sweat rate (S), were measured. After moderate intermittent heat exposures (7 times for 1h at T_R=42.5C) the experiments started again. From GTC, LTC, or as functions of T_R, no new knowledge about thermoregulatory or adaptive mechanisms was available. The high in the cold stimulated left hand, however, and the oscillatory thresholds (_OSC) for rhythmic vasomotion indicated the peripheral influence of skin temperature, as well as local, mean skin temperature (¯T_s) and core temperature. When exposed to moderate temperature decreases or increases the body seems to react only with increasing thermal resistance by vasoconstriction or an increase of sweat rate, respectively. Moderate heat adaptation is only able to raise sweat rate, but not the thresholds and gain of the S-function. We assume that functional studies of adaptive modifications in humans must be conducted at temperatures greatly beyond those used in these experiments.     

Expression of a bovine κ-CN cDNA in the mammary gland of transgenic mice utilizing a genomic milk protein gene as an expression cassette

Transgenic mice were produced by microinjection of a DNA construct composed of the bovine -casein (-CN) cDNA under the control of the goat -CN 5 promoter elements and 3 flanking regions into pronuclear-stage embryos. The gene construct targeted the expression of bovine -CN RNA to the mammary gland and secretion of bovine -CN in the milk. In the three lines studied (BC-7, BC-31 and BC-67) the transgene was stably integrated and propagated as a Mendelian locus. Expression of the bovine protein in lactating mice from the three transgenic lines was demonstrated by northern and western blots. In ten different tissues analysed by northern blotting, expression was confined to the mammary gland of lactating transgenic mice from line BC-7, with low-level expression also observed in the salivary gland of lines BC-31 and BC-67. Transgene expression in the mammary gland paralleled normal casein gene expression during lactation and was not observed in virgin females. The level of bovine -CN mRNA expression on day 10 of lactation in hemizygous transgenic females in relation to endogenous mRNA of whey acid protein (WAP) gene expression was 14%, 69% and 127% in lines BC-7, BC-31 and BC-67, respectively. No association between transgene copy number and expression was observed. The bovine -CN concentration in milk on day 10 of lactation ranged from 0.94 to 3.85 mg of protein per ml of milk. The bovine -CN expressed in mouse milk had the same molecular mass and immunoactivity with polyclonal antibodies as did -CN from bovine milk. A high degree of variation in the production of bovine -CN within each of the transgenic lines was observed.     

Obere grenzen von flora und vegetation in der nivalstufe der zentralen ötztaler alpen (tirol)

Summary The authors give a short introduction into the geological und climatical conditions of their area of investigation. As a criterion to characterize the Nivalstufe (nivale zone) they not as usual use the climatical limit of the perpetual snow but the more natural limit of the alpine pioneer grass heath in the height. As the most important types of vegetation are reported: the Curvuletum, Elynetum, snowbeds, cushion plants, rock- and scree vegetation. In a table they compare the appearance of 104 vascular plants growing above 3000 m in the Tyrolian (Ötztaler) alps with those of the western alps.     

Modelling endplate currents: dependence on quantum secretion probability and decay of miniature current

Quantification of the time course and amplitude of endplate currents (EPC) was made with respect to dispersion of quanta secretion and to changes in the exponential decay of miniature endplate currents (_mepc). The relationship between RPC amplitude and _mepc follows a double-exponential curve with ₁= 0.3 ms and ₂ = 6 ms. If the amplitude of fully synchronised EPC is taken as 100%, then the loss of EPC amplitude is already 42% with physiological parameters of dispersion (the half-rise and decay constant of distribution of secretion probability = 0.5 ms, _mepc =1 ms). This loss is even more substantial if secretion is more dispersed or miniature endplate currents decay faster. Correspondence to: F. Vyskocil     

Cell and endophyte structure of the nitrogen-fixing root nodules ofCeanothus integerrimus H.and A.

Summary The nitrogen fixing root nodules ofCeanothus integerrimus were very similar in appearance to other non-legume nodules. Each nodule was a cluster of small lobes. Each lobe in cross section had a central vascular cylinder and a hypertrophied cortex. The cortex contained very large infected cells, with large nuclei; among these infected cells were scattered small, normal-appearing cortex cells. The actinomycete endophyte consisted of wavy hyphae 0.4 m in diameter which terminated in pear-shaped vesicles 1.6 m×2 m. The vesicles were not septate. The function of the vesicles was unknown. The infected cells had apparently normal nuclei, chloroplasts and mitochondria and were probably alive, except at the base of the nodule where both infected cells and the endophyte they contained were dead.     

Effects of aquatic macrophytes on water quality and phytoplankton communities in shallow lakes

We investigated aquatic macrophytes, water quality, and phytoplankton biomass and species composition in three shallow lakes with different levels of vegetation cover and nutrient concentration in Kushiro Moor, during August 2000. Trapa japonica can live in a wide range of nutrient levels. This species forms an environment with a steeper extinction of light, higher concentrations of dissolved organic carbon (DOC), lower concentrations of dissolved oxygen (DO) near the bottom, and lower concentrations of nitrate+nitrite and soluble reactive phosphorus (SRP) than other vegetation types. The pH was much higher in a Polygonum amphibium community, and the DO near the bottom did not decrease compared to a T.japonica community in the summer. The relationship between chlorophyll a and the limiting nutrient (total phosphorus (TP) when total nitrogen (TN):TPis 10 and TN/10 when TN:TP is <10) significantly differed between lakes with and without submerged vegetation. The chlorophyll a concentrations at a given nutrient level were significantly lower in water with submerged macrophytes than in water without them. Correspondence analysis showed that the difference in phytoplankton community structure across sites was largely due to the presence or absence of submerged macrophytes, and the ordination of phytoplankton species in the lakes with submerged macrophytes is best explained by environmental gradients of TN, chlorophyll, pH and SRP.     

Determinants of Phencyclidine Potency on the Nicotinic Acetylcholine Receptors from Muscle and Electric Organ

1.Phencyclidine (PCP) is an inhibitor of the nicotinic acetylcholine receptor (AChR) with characteristics of an open-channel blocker. The location of PCP binding site on the AChR molecule is unknown.2.PCP inhibits the AChR from electric organ with a higher potency than muscle AChR. To find the molecular basis of this difference, we expressed the two native and six hybrid receptors, and two receptors containing mutated mouse subunits in Xenopus laevis oocytes. The inhibition of ACh-induced current in these receptors by PCP was studied using whole-cell voltage-clamp. All hybrid receptors generated robust ACh-induced currents, while incomplete receptors (-less or -less) did not.3.PCP potency was higher on hybrids containing Torpedo and subunits regardless of the and subunit origin. A mouse subunit containing the asparagine 6 to the serine mutation in the M2 segment conferred a high sensitivity to PCP.4.These results support the conclusion that the amino acid residues at the position 6 of the M2 segments contribute to the PCP potency difference between Torpedo and mouse receptors.5.Another noncompetitive inhibitor of the AChR, the cembranoid eupalmerin acetate (EUAC), also inhibited the electric organ receptor with a somewhat higher potency than muscle AChR. However, the IC₅₀ values for EUAC inhibition of hybrid receptors did not follow the pattern observed for PCP. Therefore, these two inhibitors interact differently with the AChR molecule.     

Genetically determined differences in the response of alpha1-antitrypsin levels in human serum to typhoid vaccine

Summary Normal individuals and those homozygous and heterozygous for the gene which determines deficiency in serum ₁-antitrypsin (₁-at) were given an intravenous injection of typhoid vaccine. Following this injection the trypsin-inhibiting capacity of serum and the concentration of ₁-at increases markedly in normal individuals. Heterozygotes for the deficiency gene have an elevation of ₁-at and trypsin-inhibiting capacity of their serum but reach only 50 percent of the levels reached by homozygotes for the common gene (normal individuals). Their values are however temporarily in the range of normal men not given typhoid vaccine. Homozygotes for the deficiency gene show only a small elevation of ₁-at under these conditions. These findings demonstrate that (1) the increase in trypsin-inhibiting capacity of serum after an injection of typhoid vaccine is largely due to the elevation of the ₁-at concentration, and (2) the ₁-at deficiency gene inhibits the quantitative response of the ₁-at to such a stimulus.Supported in part by USPHS grant HE-06285 from the National Heart Institute.Some of these studies were carried out in the General Clinical Research Center Ward, U. C., FR-79, supported by the Division of Research Facilities and Resources, U.S. Public Health Service.     

Darwin on Aristotle

Charles Darwin's famous 1882 letter, in response to a gift by his friend, William Ogle of Ogle's recent translation of Aristotle's Parts of Animals, in which Darwin remarks that his “two gods,” Linnaeus and Cuvier, were “mere school-boys to old Aristotle,” has been thought to be only an extravagantly worded gesture of politeness. However, a close examination of this and other Darwin letters, and of references to Aristotle in Darwin's earlier work, shows that the famous letter was written several weeks after a first, polite letter of thanks, and was carefully formulated and literally meant. Indeed, it reflected an authentic, and substantial, increase in Darwin's already high respect for Aristotle, as a result of a careful reading both of Ogle's Introduction and of more or less the portion of Ogle's translation which Darwin says he has read. Aristotle's promotion to the pantheon, as an examination of the basis for Darwin's admiration of Linnaeus and Cuvier suggests, was most likely the result specifically of Darwin's late discovery that the man he already knew as “one of the greatest ... observers that ever lived” (1879) was also the ancient equivalent both of the great modern systematist and of the great modern advocate of comparative functional explanation. It may also have reflected some real insight on Darwin's part into the teleological aspect of Aristotle's thought, indeed more insight than Ogle himself had achieved, as a portion of their correspondence reveals. This revised version was published online in July 2006 with corrections to the Cover Date.