Recent Workers Research Articles

Infectivity of Trypanosoma brucei-subgroup Flagellates Maintained in Culture

Virulence and infectivity of 4 Trypanosoma brucei-subgroup pleomorphic strains: T. brucei EATRO (E) 795 and 1587, and T. rhodesiense E1895 and Bechuanaland (B) 182A, cultivated in modified Tobie's medium (Tm), were tested in C57BL/6J mice. The 3 freshly isolated EATRO strains could be maintained in Tm by serial transfers, but B182A strain, with a history of , 29 syringe passages in laboratory rodents, was difficult to cultivate. Populations of this latter strain contained many rounded and multinucleate forms both in the bloodstream of mice and in culture. Inocula with identical trypanosome numbers were used in all experiments. Strains E795 and E1895 lost all infectivity for normal mice by the 3rd day of cultivation and strain E1587 remained infective for , 40% of the inoculated animals on the 4th day; even 5-day cultures of strain B182A caused lethal parasitemia in ~ 40% of the infected mice. In all instances, infectivity and virulence of cultured trypanosomes could be correlated with percentages of nontransformed bloodstream forms (LS, ISS, SS) present in the cultures, no infection apparently being caused by cultures with less than 20% of such forms. Judging from the survival lengths of mice, the 3 EATRO strains were about equally virulent, while virulence of T. rhodesiense B182A trypanosomes was significantly higher. Essentially identical results were obtained with strain E1895 after 1, 2, or 3 syringe passages in mice. Among hydrocortisone-treated mice, lethal parasitemias (in , 40% of animals) resulted from inoculations of strains E795 and E1895 maintained in Tm medium for up to 6 days, less than 10% of bloodstream forms present in cultures being sufficient for the development of infection in animals whose immune mechanisms were affected by the hormone. The period for which cultures of strain E1895 remained infective and virulent for normal mice could be extended to 5 days by maintaining the parasites in the presence of L cell cultures. Under these conditions, transformation of bloodstream to culture forms appeared to be delayed. The implications of all the results are discussed in the light of the available morphologic, biochemical, and immunologic data. Trypanosoma brucei-subgroup pleomorphic strains rapidly lose infectivity and virulence for mice in the course of in vitro cultivation (for pertinent references see Honigberg, 1967). According to certain early reports (Behrens, 1914; Novy and MacNeal, 1904) these attributes were not lost completely in trypanosomes grown in NNN-type media. Several more recent workers were able to maintain or restore virulence and infectivity for mice in trypanosomes cultivated in Weinman's (1946) medium, but only after addition of trehalose (Weinman, 1957, 1960), arabinose, or inositol (Geigy and Received for publication 25 May 1972. * This investigation was supported by Research Grants AI00742-16, 17, from NIAID, U. S. Public Health Service. t Dr. Yolanda Mendez was a Research Associate in Zoology at the University of Massachusetts, Amherst, from September 1970 to June 1972. Her present address is P. O. Box 3410, Panama City 4, Panama. + Reprint requests should be sent to Dr. B. M. Honigberg, Department of Zoology, Morrill Science Center, University of Massachusetts, Amherst, Massachusetts 01002. Kauffmann, 1964). Other investigators, however, were unable to verify these results (Lehmann, 1961; Williamson in Geigy and Kauffmann, 1964, among others), and according to Bowman et al. (1960) the culture forms could not utilize trehalose. The source of blood used in the preparation of Weinman's medium and the age of cultures also were found to affect infectivity and virulence of the parasites (Amrein and Hanneman, 1969; Amrein et al., 1965). Until quite recently, it has been assumed that the infectivity and virulence loss among T. brucei-subgroup trypanosomes was primarily a physiologic phenomenon, not necessarily related to structural changes. Indeed, light-microscopic observations indicated that trypomastigotes, virtually indistinguishable in structure from the metacyclic forms occurring in tsetse salivary glands, developed in cultures of Trypanosoma rhodesiense and Trypanosoma gambiense strains maintained in different media (Lehmann, 1961; Weinman, 1953). The question still remains, however, whether trypano-

Tests of the Stability and Time-Step Sensitivity of Semi-Implicit Reservoir Stimulation Techniques

Abstract A reservoir simulation technique that employs semi-implicit approximations to relative permeabilities exhibits excellent stability and permeabilities exhibits excellent stability and convergence characteristics when applied to water- or gas-coning problems. Recent workers in this area have made a simplifying assumption in order to linearize the flow terms of the semi-implicit finite-difference equations. This paper describes a method of solving efficiently paper describes a method of solving efficiently the nonlinear form of the equations and demonstrates that time-step sensitivity is reduced by iterating on the nonlinear terms. In addition, it addresses the problem of allocating a well's production among multiple grid blocks. Example problems include both water-coning and gas-percolation applications. Introduction Multiphase reservoir simulators traditionally have employed finite-difference approximations in which relative permeabilities are evaluated explicitly at the beginning of each time step. Simulators of this type are capable of handling many reservoir studies in a perfectly satisfactory fashion, but they are incapable of solving economically problems characterized by high flow velocities. Included in this category are the studies of such phenomena as well coning and gas percolation. The difficulty in such problems is a stability limitation imposed by the use of explicit relative permeabilities. In an attempt to overcome this permeabilities. In an attempt to overcome this limitation, Blair and Weinaug developed a simulator that employed implicitly evaluated relative permeabilities. The increased stability of their permeabilities. The increased stability of their equations allowed the use of time steps much larger than previously possible, but this was counteracted by an increase in the computational work per time step and an increased difficulty in the iterative solution of the difference equations. While the net result was a significant advance in the solution of coning problems, improvements still were needed to increase the dependability and decrease the cost of obtaining solutions for such problems. More recently, two papers were published describing a method that employs semi-implicit relative permeabilities. This method is greatly superior to the fully implicit method, both in computational effort and maximum time-step size. In developing this method, the previous workers made a simplifying assumption to obtain linear finite-difference equations. We have developed a reservoir simulator based on the nonlinear form of the semi-implicit finite-difference equations. This paper describes the techniques used in the simulator and presents the results of some tests conducted with it. These include time-step sensitivity studies and tests of alternate production allocation methods. Some of these tests compare the nonlinear form of the semi-implicit method with the linear form. SPEJ P. 253

A multivariate statistical study of skull measurements of five taxa of gazelles

A multivariate analysis using canonical variates and the D2 test show that five taxa of Palaearctic gazelles examined are distinct. Several forms of gazelles of dubious taxonomic position were also compared on the canonical axes, with conclusions not dissimilar to those of recent workers on the Arabian gazelles, viz. that there are three distinct species in the Arabian peninsula; Gazella dorcas saudiya, Gazella gazella arabica and Gazella subgutturosa marica. Gazella dorcas populations in Somalia have a local form in G. dorcas pelzelni distinct in horns but not in skull measurements from Gazella spekei in the nearby highlands.

Problems on the origin of ore deposits in the lower Ordovician formations of east Tennessee

Most recent workers in the East Tennessee zinc and barite districts are in general agreement that the host breccias were formed by solution-collapse processes in early Middle Ordovician time, probably in an ancient carbonate aquifer system of regional extent. There is little agreement, however, on the source and nature of the ore fluids from which the epigenetic minerals were formed. In this symposium Hanshaw and his colleagues have presented evidence in support of the concept that much secondary dolomite may have been formed by ground water. On the other hand, Roedder has shown that fluid inclusion studies indicate hot saline brines (75 degrees -150 degrees C) as the source fluids for the ore minerals, and he suggests that they may have been deeply circulating connate brines. Other investigators in the past have proposed a variety of source fluids, including juvenile waters, meteoric waters that have become enriched by the leaching of particular elements from the surrounding rock, and sea water.In the zinc deposits, sphalerite is accompanied locally by minor amounts of galena and pyrite, and occasionally, traces of chalcopyrite. Dolomite is the chief gangue mineral and is associated with lesser amounts of quartz, calcite, barite, fluorite, anhydrite, gypsum, and bitumen. Some deposits containing barite as the dominant ore mineral have various amounts of fluorite and pyrite; sphalerite and galena may be present locally along with the other gangue minerals typical of the zinc deposits. The paragenetic sequences of the minerals have been determined for most of the mines and many of the prospects, and, except for minor refinements, will be little changed by additional studies. The real problem, though, is the correlation of these depositional sequences from mine to mine and from district to district. Perhaps the major difficulty in the correlation is the seemingly uncomplicated mineralogy that disguises a rather complex regional paragenesis.Questions regarding the routes the ore fluids travelled to reach the sites of deposition, the reasons why the ores are concentrated in some areas more than others, and the reasons why the mineralogy varies from area to area are questions that are unanswered or at best only partly answered. Studies to date have produced convincing evidence concerning the nature of the structures and the physical conditions responsible for the localization of ore in the Kingsport Formation (Lower Ordovician). On the other hand, the relation of the Kingsport ores to the smaller deposits in the underlying Lower Ordovician and Cambrian rocks is but little understood, and no final answer to the origin of these deposits can be reached until this relationship has been satisfactorily explained.Fluid inclusion studies, trace element analysis, and isotopic studies of all sorts are needed to further our understanding of these seemingly simple ores. Continued detailed studies of field relations, both regional and local, are of major importance, not only for what they will reveal in themselves, but also to perfect the frames of reference in which to place the growing mass of laboratory data.

Evidence on the age of barite, zinc, and iron mineralization in the lower Paleozoic rocks of east Tennessee

Based on a study of minor occurrences of zinc, barite, and iron in East Tennessee, certain deposits are interpreted to have formed during early Middle Ordovician time. Principal lines of evidence supporting this age are: (1) the occurrence of barite, sphalerite, and pyrite associated with synsedimentary collapse breccias which span the pre-Middle Ordovician unconformity at the Lost Creek barite mine in Union County; (2) barite in basal Middle Ordovician beds (Athens Shale and Lenoir Limestone) in northeastern Tennessee and southwestern Virginia; (3) sphalerite and pyrite in dolomite filling paleocaves in the uppermost part of the Lower Ordovician Mascot Dolomite at the Trotter prospect near Douglas Dam in Sevier County; and (4) oolitic hematite and pyritiferous beds near the base of the Athens Shale and subjacent pyritiferous collapse breccias in the Mascot and Kingsport Formations at several localities along the eastern side of the Appalachian Valley. Thus, it is concluded that ascending solutions formed epigenetic deposits in pre-Middle Ordovician carbonate strata nearly contemporaneously with syngenetic deposits in early Middle Ordovician sediments.These findings are in general accord with those of recent workers in the Mascot-Jefferson City and Copper Ridge districts who have proposed that mineralization in these areas occurred during the time interval of pre-Middle Ordovician erosion. The long-held theory which associates mineralization with late Paleozoic diastrophism is not supported.

The Thelypteris normalis Complex in the Southeastern United States

The species of the Thelypteris normalis complex in the southeastern United States and the West Indies have long been acknowledged as taxonomically troublesome. The first person to monograph the group was Christensen (1913), who treated it under Dryopteris, subg. Cyclosorus. More recent workers have also recognized the integrity of the group, but generally have treated it as a subgroup of Thelypteris (Small, 1938; Wherry, 1943, 1964). The chief problems encountered by Christensen and others have been the extreme variability in the species and the large number of forms which are seemingly intermediate between species. Robert and Edward St. John, avid collectors of Florida ferns in the 1930's, added to the proliferation of names when they described numerous Florida endemics. The assiduousness of previous workers, however, has laid the groundwork for more detailed studies utilizing cytology and field-to-greenhouse transplants, an approach which I believe has clarified the systematics of the group. A revision of Thelypteris sect. Cyclosorus in the New World is currently being prepared for future publication. However, in order that the important conclusions of this study might be more immediately available to those with an interest in ferns of the southeastern United States and to those involved in the preparation of floras, it seems appropriate to publish a portion of the study dealing with the species of this area. Following a key to the species and varieties is a synopsis of the southeastern United States taxa, excluding T. totta (= T. gongylodes), which is only rather distantly related to species in the T. normalis complex. Important aspects of synonymy, habitat, distribution, and a discussion of

Nueces River Delta Plain of Pleistocene Beaumont Formation, Corpus Christi Region, Texas

The surface of the Beaumont Formation in the Corpus Christi region of Texas preserves a relict depositional pattern laid down by a Pleistocene Nueces River during an interglacial or high sea-level stage like the present. The depositional pattern can be interpreted either as (1) that of a small meandering stream, similar to the present Nueces, undergoing numerous course changes (avulsions) and terminating in a small delta, or (2) that of a large multi-active distributary delta, similar to the present Mississippi River. Hydrologic considerations and comparisons with the contemporaneous Trinity, Brazos, and Colorado delta plains, some of their Holocene successors, and the Holocene Rio Grande and Mississippi deltas seem to rule out the second hypothesis. The sediments directly underlying the delta plain are largely fine grained--about 75 percent clay and about 25 percent very fine to fine sand. Both the areal extent and the assignment of the delta plain to the Beaumont Formation are controversial. Early mappers depicted it as larger in area. Most recent workers have assigned it to the Montgomery Formation (upper Lissie) or its equivalents. Depositional patterns, local surface gradient changes, and air photo patterns are of greater utility in correlation than similarity of regional gradients and soil types upon which previous correlations were based. A consequence of this assignment is the contemporaneity of the Beaumont-age delta plain and the relict Ingleside barrier offshore from it.

Estimation of Maximum Wind Speeds in Tornadoes

A method is proposed for rapidly estimating the maximum value of the azimuthal velocity component (maximum swirling speed) in tornadoes and waterspouts. The method requires knowledge of the cloud-deck height and a photograph of the funnel cloud—data usually available. Calculations based on this data confirm that the lower maximum wind speeds suggested by recent workers (roughly one-quarter of the sonic speed for sea-level air) are more plausible for tornadoes than the sonic speed sometimes cited a decade ago. Comparison in a few cases with maximum wind speeds determined either by spray-tracking on motion pictures of a waterspout or by another method reported by the authors elsewhere (using the tephigram for air at the outer edge of the whirl) yields compatible results. DOI: 10.1111/j.2153-3490.1970.tb00513.x

Personality, body build and adrenocortical activity.

In recent years research workers have shown a relative lack of interest in the constitutional correlates of normal personality. However, recent findings in the field of psychosomatic medicine suggest the need for a careful reexamination of this field of research. Several studies have indicated that breast cancer, lung cancer, and myocardial infarction patients are more extraverted and less neurotic than hospital control group patients (Eysenck, 1965). Also, duodenal ulcer patients have been reported as being both introverted and neurotic (Kanter and Hazelton, 1964).

Structure of Pseudohornera bifida (Eichwald)

Abstract The structure of the skeleton of the bryozoan Pseudohornera bifida (Eichwald) is described in detail. The wall structure is composed of a central granular layer flanked by laminated tissue. The granular layer predates the laminated layer. The skeleton is provided with numerous calcareous rods originating from the granular layer. The soft tissues have been reconstructed. The inner epithelium, secreting the skeleton, and the outer, secreting the cuticle, were probably separated by a hypostegal coelomic cavity. The structure of the skeleton in Pseudohornera bifida confirms the position of the Phylloporinidae near the fenestrate cryptostomes, as suggested by recent workers. The relations of the stenolaematous groups provided with granular walls are briefly discussed.

Estimation of Maximum Wind Speeds in Tornadoes

A method is proposed for rapidly estimating the maximum value of the azimuthal velocity component (maximum swirling speed) in tornadoes and waterspouts. The method requires knowledge of the cloud-deck height and a photograph of the funnel cloud–data usually available. Calculations based on this data confirm that the lower maximum wind speeds suggested by recent workers (roughly one-quarter of the sonic speed for sea-level air) are more plausible for tornadoes than the sonic speed sometimes cited a decade ago. Comparison in a few cases with maximum wind speeds determined either by spray-tracking on motion pictures of a waterspout or by another method reported by the authors elsewhere (using the tephigram for air at the outer edge of the whirl) yields compatible results.

Taxonomic Position of Lippistes Pehuensis Marwick, with a Review of the Species of Concholepas (Gastropoda, Muricidae)

Summary Lippistes pehuensis Marwick, 1926, placed in Hartungia Bronn (Janthinidae) by recent workers, is transferred to Concholepas Lamarck (Muricidae) on the basis of its resemblance to the Australian Miocene C. antiquata Tate, 1894. C. antiquata Tate is redescribed, and other species of Concholepas are briefly reviewed.

A Short History of Psychiatry.

In this slender volume Professor Ackernecht presents the reader with an overview of the history of psychiatry that, while brief and incisive, manages to touch on the major movements in psychiatric thought over the centuries. In such a brief volume presentation of systems of ideas is necessarily abbreviated and the reader may well feel that the theories of such diverse workers as Freud and Janet, Charcot and Kretschmer are not adequately presented. The author rightfully feels that one need not be a psychiatrist to write a history of psychiatry. However, when the space allowed is so brief, selection is important, and not all readers will be pleased with Ackernecht's omissions: S. Weir Mitchell and Robert B. Carter are among relatively recent workers completely omitted from the book, and their absence may be a real detriment to the English speaking psychiatrist. Finally, at the

Centrioles in the Spermatids of Insects1

The University of Texas at Austin There have been many statements published regarding the number of centrioles in the spermatids of insects. Some earlier workers reported the occurrence of 2 centrioles in several groups of insects, although only one was seen in the spermatids of some species (summarized in Wilson 1928). More recent workers have reported similar results, although in some publications the investigators were apparently not specifically interested in the number of centrioles present. For example, Bertaud and Gatenby (1960) state that in a cricket, Pachyrhamma fasciferum (Walker), 2 apparently true centrioles are present. Mathur (1960) reported 2 centrioles in 1 grasshopper, Stenobothrus viridula (=Omocestus viridulus (L.), but he found no evidence for 2 in the normal spermatids of another species, Schistocerca gregaria (Forskal). Only 1 centriole is discussed in a recent paper by Phillips (1966), which considers spermiogenesis in the fungus gnat, Sciara coprophila Lintner.

A revision of the genus 0valipes Rathbun, 1898 (Crustacea, Decapoda, Portunidae)

Recent workers have recognized five species in the genus Ovalipes: O. ocellatus (Herbst, 1799), O. punctatus (de Haan, 1833), O. guadulpens is (Saussure, 1858), O. iridescens (Miers, 1886), and O. molleri (Ward, I933). However, five species have been confused under the name of O. punctatus and these comprise: O. punctatus (de Haan, 1833), O. trimaculatus (de Haan, 1833), O. catharus (White, 1843), O. australiensis n.sp., and O. elongatus n.sp. A further new species, O. georgei, has appeared in recent collections from Western Australia, and it seems that there may be two forms of O. guadulpensis. The new species are described and the remaining species redescribed. This has necessitated a redescription of the generic features and consideration of the possibility of either dividing the genus into several genera or erecting subgenera. Neither of these possibilities has been followed, but, instead, two groups have been designated (A and B), each with two subgroups. Thus the O. punctatus subgroup contains O. punctatus, O. trimaculatus, O. catharus, O. australiensis, and O. elongatus, and, with the O. georgei subgroup comprising only O. georgei, makes up Group A. The O. iridescens subgroup comprises O. iridescens and O. molleri, and with the O. ocellatus subgroup comprising O. ocellatus and O. guadulpensis makes up Group B.

Serum cholesterol levels in anorexia nervosa.

IN CONTRAST to earlier investigators (Pardee, 1941; Stephens, 1941; Emmanuel, 1956) more recent workers (Crisp, 1965a, 1967; Oberdisse, Solbach & Zimmerman, 1965; Klinefelter, 1965; Crisp & Stonehill, 1967) have reported that some of their patients with anorexia nervosa have high serum cholesterol levels. Crisp (1965a, b, 1967) in a study of eighty patients (Nos. 1-80) has also emphasized that anorexia nervosa is predominantly a state of severe chronic carbohydrate starvation having its origins in the patient's phobia of and consequent need to avoid normal adolescent weight. Such patients who will have initially turned to eating supposedly 'non-fattening' foods such as as cheese, fruit, meat and salad, may later surrender to their increasing impulse to eat carbohydrate by having binges. They may start to vomit in relation to their binges and conceal and deny one or both these aspects. Usually such binges also alternate with phases when the patient stops eating altogether. Such cycles may recur every 24 hr or may span several weeks. These complex and often interrelating patterns of feeding make it more than usually difficult to assess the past dietary intake. Meanwhile, a further study by Crisp et al. (1967) has confirmed that thirty-seven female patients aged 14-33 with anorexia nervosa had significantly higher serum cholesterol levels (P<0 0002) than thirty-seven normal women with whom they were matched individually for age (Fig. 1). The serum cholesterol levels in the control group are the mean of two results from the two halves of the menstrual cycle. However, there was a wide variation of serum cholesterol levels amongst the anorexia nervosa group. It was confirmed that such levels bore no relationship to thyroid function or reduced plasma volume and were unlikely to be due to diminished oestrogen activity, a universal characteristic in

Dropwise condensation—some factors influencing the validity of heat-transfer measurements

Reports, of various recent workers in the field of dropwise condensation, suggest that precise and repeatable measurements of the steam-to-surface temperature difference can only be obtained when special precautions are taken to obviate the effects of non-condensing gases. In the present work, the effects of local venting (i.e. removal of vapour from the vicinity of the condensing surface) were studied. The aim was first to demonstrate that even minute concentrations of non-condensing gases, such as remain in steam after prolonged boiling, can lead to significant errors in measurements of the steam-to-surface temperature difference for dropwise condensation, and second, to investigate the possibility of avoiding such errors by venting without, at the same time, incurring error through disturbance of the condensate. For a copper condensing surface, promoted with dioctadecyl disulphide (C 18H 37SSC 18H 37), the time dependence of the steam-side heat-transfer coefficient was also investigated so as to assess the importance of this factor on the repeatability of observations. Conditions were established for which repeatable results, relating to “gas-free” steam, may be obtained. While operating under such conditions, observations of the steam-to-surface temperature difference were made for a wide range of heat-flux. For these tests, vertical plane copper condensing surfaces, promoted with dioctadecyl disulphide, were used. The steam pressure was about 1·07 bar. The results are compared with those of other recent workers.

The effect of verbal context on the recall of schizophrenics and other psychiatric patients.

Recent workers investigating psychological dysfunction in schizophrenic patients have stressed the fact that such patients appear to have some specific difficulty in speech perception. It has been claimed that schizophrenics require more cues in order to reproduce verbal material accurately. This disability has been analysed by methods inspired by the work of communication engineers.

Fine Structure of the Hydatid Cyst and Protoscolex of Echinococcus granulosus

The fine structure of various parts of the hydatid cysts and the enclosed protoscolex is described. The contents of the brood capsule are PAS-positive following extraction treatment with amylase. This material is made up of fine irregularly arranged filaments, and remains as a coating over the posterior aspect of the protoscolex after its removal from the brood capsule. It has completely disappeared after 42 days in vitro. The posterior aspect of the protoscolex is with knoblike projections which are probably undeveloped tegumental projections. After 42 days culture in vitro this area has fully developed tegumental projections. Multinucleation of tegumental cells is common in the protoscolices cultured for 42 days in vitro. The various organ systems are described and compared with similar structures reported for tapeworms and other invertebrates. Although the teguments of several species of adult tapeworms have been examined by electron microscopy, the fine structure of the intermediate stages in their life history has been neglected. Goldschmidt (1900) was apparently the first to describe the spines on the body surface of developing protoscolices of Echinococcus granulosus, and subsequently Coutelen (1927) described the surface distribution of these spines in more detail. These authors, though limited to light microscopy, stated that the spines were seen only under ideal conditions with an oil immersion objective. More recent workers have made similar observations on the cystic stage of several taeniid tapeworms (Crusz, 1948; Voge, 1962, 1963). Waitz (1961) in describing the ultrastructure of the cystic stage of Hydatigera taeniaeformis mentions the presence of microvilli on the body surface. Larsh et al. (1965) in a study on the histopathology of infections in mice with the cystic stage of Multiceps serialis include an electron micrograph of a portion of cyst wall (their figure 7). Although a discussion of the fine structure is outside the scope of their paper, it is significant that their illustration clearly shows surface projections, vesicles within the tegument, and dark structures which may be mitochondria. Siddiqui (1963) examined the tegument of cysticerci of Taenia saginata, T. hydatigena, and T. pisiformis and noted that all three species were covered with hair-like processes. In an account of the ultrastructure of the Received for publication 27 July 1966. cystic stage of M. serialis, Race et al. (1965), reported that the subcuticular canals connect the cuticle with the parenchyma. Marzullo et al. (1957) reported the presence of mucopolysaccharides in the cyst of E. granulosus. Kilejian et al. (1961) demonstrated that the brood capsule contents are PAS-positive after saliva treatment. The electron microscopic appearance of this material has not previously been demonstrated. The investigation reported in this paper is an extension of previous work on the fine structure of adult taeniid tapeworms (Morseth, 1965, 1966) and especially that of E. granulosus. MATERIALS AND METHODS

The Effect of Temperature on the Oxygen-linked Ionizations of Hemoglobin

Abstract On the assumption that only two of the acid per heme are affected by oxygenation, the in electrical charge, ΔX, between oxygenated and deoxygenated hemoglobin (O2Hb and Hb) at the same pH (as determined from the in their titration curves) is given by the equation. [see PDF for equation] where h = hydrogen ion concentration and Ko, K'o, Kr, and K'r are the ionization constants of these Bohr groups in O2Hb and Hb, respectively. The above equation has been found to fit (within the limits of experimental error) the data on the difference titration curves for bovine, human, and horse O2Hb and Hb over the pH range 5.0 to 9.3 at 25–37°; best (i.e. least mean square) values of the ionization constants have been estimated statistically by means of an automatic computer program, written in Fortran language. Thus, for human hemoglobin at 25°, pKr = 7.84 (±0.006), pKo = 6.84 (±0.009), pK'r = 5.13 (±0.04), and pK'o = 5.60 (±0.03). These figures differ by up to 0.7 pK unit from those obtained by other recent workers, who did not, however, analyze their data statistically. Values for the corresponding heats of ionization, Qo, Q'o, Qr and Q'r, have been calculated from the effect of temperature on the respective ionization constants. The most accurate results have been obtained in the case of human hemoglobin, wherein it is found that (Qr - Qo) is 5,000 (±800) cal. The actual value of Qr is of the order of 11,000 cal and thus lies outside the usual range for the heat of ionization of imidazole and its derivatives. These conclusions are based upon the experimental data not only of the present paper but also of the recent paper (11) of Antonini, Wyman, Brunori, Fronticelli, Bucci, and Rossi-Fanelli, the concordance between these two independent sets of results, when statistically analyzed, being very satisfactory. (Q'o - Q'r) has also been found to be of the order of 5000 cal, but this figure is subject to a wide margin of uncertainty, owing to the difficulty in obtaining accurate estimates of pK'o and pK'r from data in the acid pH range, wherein hemoglobin is unstable. Preliminary experiments have shown that at pH below 6.2 rapid titration figures (i.e. within 10 msec) differ significantly from the results obtained by the customary slow titration procedure, which takes several minutes. The results of this paper are discussed in light of current views on the chemical and x-ray structure of O2Hb and Hb.