Microtubule initiation at kinetochores and centrosomes in lysed mitotic cells. Inhibition of site-specific nucleation by tubulin antibody.

A lysed cell system was developed to determine whether tubulin antibody can block the nucleation of exogenous tubulin at kinetochores and centrosomes. Mitotic PtK2 cells were pretreated with colcemid to remove all endogenous microtubules and were lysed with Triton X-100 in PIPES-EGTA-Mg++ buffer. This procedure left centrosomes, chromosomes, and kinetochores intact as determined by electron microscopy of thin-sectioned cells. Exposure of the lysed cells to phorphocellulose-purified tubulin dimers at 37 degrees C in the presence of 1 mM GTP resulted in site-specific nucleation of microtubules at centrosomes and kinetochores. Treatment of the lysed cell preparations with tubulin antibody before subsequent exposure to the exogenous tubulin resulted in almost complete blockage of microtubule nucleation, especially at kinetochores. Pretreatment of the lysed cell preparations with control antibody or buffer without antibody had no effect on the ability of centrosomes and kinetochores to initiate microtubule assembly. The implications of these results with respect to the molecular composition of centrosomes and kinetochores are discussed.


Blue light-induced, intrinsic vacuolar fluorescence in onion guard cells.

Guard cells of onion irradiated with broad-band blue light display a green intrinsic fluorescence. The fluorescence has been found in eleven species of Allium, but it has not been observed in any other monocot or dicot examined. The fluorescence occurs only in guard cells and is absent in neighbouring epidermal cells. During development it is first apparent in guard mother cells soon after the asymmetric division. Microscopic observation reveals that the fluorescence is associated with the vacuole and examination of vacuoles isolated from guard cell protoplasts suggests that it may be localized on the tonoplast. Microspectrophotometric analysis of single cells reveals an emission peak at around 520 nm. Our results are consistent with the view that this blue light receptor is a flavin or flavoprotein and that it might be related to the blue light-enhanced stomatal opening observed in onion.


On the differential divisions and preprophase microtubule bands involved in the development of stomata of Vigna sinensis L.

The manifestation of premitotic cell polarity and the resultant structural asymmetry of the differential divisions participating in the development of stomata of Vigna sinensis vary considerably. However, two morphologically distinct types of differential division were distinguished: (a) 'asymmetrical differential divisions', in which the premitotic polarization of the cell, the eccentric position of the nucleus during division and the differences in size and organization of the daughter cells are obvious; and (b) differential divisions in which the above features are inconspicuous or almost absent. The former occur in the ordinary protodermal cells, the latter in some meristemoids. The organization of a sharply demarcated preprophase microtubule band (PMB) precedes, all differential and non-differential divisions. In the first type of differential division the PMB is formed eccentrically, while in the second it may display either an approximately symmetrical or a clearly asymmetrical disposition, always indicating with surprising accuracy the sites where the succeeding cell plate will join the parent walls. The PMB foreshadowing the highly curved cell plates in meristemoids I of the mesoperigenous process, as well as in meristemoids I and II of the mesogenous one, are apposed only on one anticlinal wall and therefore do not encircle the nucleus or traverse the cell. In the symmetrical divisions of guard cell mother cells (GMC), as well as in those of protodermal cells, the PMB runs right round the internal plasmalemma surface in an equatorial position, coinciding with that of the future cell plate. In the former cells the wall abutting the cortical cytoplasm traversed by the band becomes locally thickened. The variability in the pattern of the microtubules of the band along the walls of the GMC is directly mirrored in the pattern of the thickening. It seems that in GMC the PMB mediates a directed exocytosis of dictyosome vesicles. In contrast to what is now generally accepted in dicotyledonous plants, each meristemoid I of both the mesogenous and mesoperigenous stomata in Vigna sinensis leaves does not inhibit but induces the formation of other meristemoids close to it.


Increase in macromolecular amounts during the cell cycle of Tetrahymena: a contribution to cell cycle control.

Increases in RNA, protein and cell size were determined cytophotometrically during the cell division cycle of Tetrahymena. For these parameters different patterns were found. RNA accumulates slowly during G1 period and faster during macronuclear S. This agrees with the changing uridine incorporation rate which is at least partly related to the varying macronuclear DNA amount. Increases in protein content and cell size occur mainly during G1 and G2. This pattern was confirmed by determining the RNA : protein ratio in individual cells. It is minimal at the end of the G1 period. These findings and evidence from the literature suggest that initiation of DNA replication is under negative control by the relative RNA content of the cell.


An experimental analysis of bivalent interlocking in spermatocytes of the new Triturus vulgaris.

Interlocked bivalents at 1st meiotic metaphase are relatively uncommon in spermatocytes of the newt Triturus vulgaris, but their frequency of occurrence can be significantly increased by subjecting newts to a 24-h heat shock. Newt spermatocytes are sensitive to a heart shock at any stage between the end of premeiotic S and mid to late pachytene. The heat shock does not cause evidence desynapsis, nor does it significantly affect chiasma frequency; therefore the interlocked condition induced in spermatocytes which were subjected to a heat shock when they were in zygotene or pachytene is unlikely to be a consequence of synaptic trapping. By way of explanation it is suggested that a heat shock may cause telomers to detach from the nuclear membrane, or from the synaptonemal complex where the latter is attached to the membrane, thus allowing non-homologous chromonemata to become interwined before chiasmata have formed. If this explanation is valid, it is then further suggested that the recombination process which results in chiasma formation probably takes place in chromosomal regions lying outside the synaptonemal complex, rather than inside, between its 2 lateral elements.


Survival of cells implanted in the embryonic chick limb bud: a difference between normal and malignant rat brain cells.

Cells from normal rat brain tissue did not survive and few cells could be found 1 d after grafting. In contrast, cells from a glioma and a carcinogen-treated rat brain survived well and many mitoses were observed. These malignant cells also invaded the limb. The behaviour of normal and malignant cells was followed at shorter times after grafting and some invasion by the normal cells was detected. The first signs of degeneration of normal cells were apparent around 7 h after grafting, and after this the grafts progressively deteriorated. These results support the ideal that the ability of cells to survive and grow in embryonic tissues is a characteristic of malignant cells. The findings are discussed in relation to mechanisms of tumour formation.


Motility of the Limulus blood cell.

The sole cell type (the amoebocyte) found in the coelomic fluid of the horseshoe crab, Limulus polyphemus can be stimulated to become motile by extravasation or trauma. Motility was studied using time-lapse microcinematography and direct microscopic examination of cells in tissue culture and in gill leaflets isolated from young animals. Phase-contrast and Nomarski differential-interference contrast optics were employed. Both in culture and in the gills, motile cells showed 2 interconvertible morphological types: the contracted cell, which was compact and rounded and had a relatively small area of contact with the substratum, and a flattened from with a larger area of contact. In both morphological types, motility involved the protrusion of hyaline pseudopods followed by flow of granular endoplasm forward in the pseudoplod. Cellular motility in vivo (in the gill leaflet) was morphologically identical to that displayed in tissue culture. In culture, motility was unaffected by the nature of the substratum: cells were indistinguishable on fluid (paraffin oil) or solid (glass) substrata or on hydrophobic (paraffin oil, siliconized glass) or hydrophilic (clean glass) surfaces. Cells migrated and spread on agar surfaces. Cell motility was unaffected by high concentrations (100 micrograms/ml) of the microtubule-depolymerizing agent colcemid and was abolished by cytochalasin B at 1 microgram/ml.


Production of nerveless Hydra attenuata by hydroxyurea treatments.

Hydroxyurea was used to produce hydra with varying nerve cell densities including a new type of nerveless animal. Hydra attenuata were treated with 10(-2) M hydroxyurea. By 23 days after treatment, 2 populations of animals are in culture. Both have a decrease in nerve cells. The first is a normal-coloured feeding animal (HU-R) and is recovering while the second is a pale non-feeding animal (HU-P). HU-P animals resemble nerveless animals in their lack of behavioural responses but they contain about 2% nerve cells. Upon hand feeding, some HU-P animals will recover but most will produce nerveless buds. Neverless hydra produced by hydroxyurea resemble nerveless animals produced by other techniques, in their behavioural, morphological and developmental properties. Normal animals, as cultured and in regeneration experiments, show a compact tentacle number distribution pattern with a small variance. Nerveless animals show broad tentacle distribution patterns with increased means and variances. It is suggested that a normal tentacle number regulatory mechanism is lacking or diminished in nerveless animals. This defect is correlated with hypostomal circumference and with nerve cells.


Kinetics of the regeneration of sea-urchin cilia. II. Regeneration of animalized cilia.

The kinetics of the regeneration of cilia of Arbacia punctulata animalized by treatment with trypsin have been examined. The cilia regenerate with biphasic kinetics: an initial linear phase which changes abruptly to a second, slower linear rate. Inhibition of protein synthesis with 10 microM emetine has little effect on the first phase but totally abolishes the second, suggesting that the first phase represents the utilization of a pre-existing precursor pool while the second reflects de novo protein synthesis. However, cilia will regenerate again following a second deciliation in the presence of emetine, to half the plateau value of the first regeneration, indicating that only a fraction of the pool of the limiting precursor can be assembled into the regenerating cilium. It is proposed that a residual pool of this precursor is required to maintain the assembly-disassembly equilibrium in favour of the assembled organelle.


Morphological alterations in the mitochondria of Amoeba proteus induced by uncoupling agents.

Ultrastructural changes in mitochondrial morphology were observed in amoebae exposed to the uncoupling agents dinitrophernol (DNP), pentachlorophenol (PCP), and m-chlorocarbonyl cyanide phenylhydrazone (CCCP). These alterations occurred with rapidity and were present before whole-cell activity changes could be detected. They included changes in profile shape and overall dimensions, matrix density changes, and alterations to the cristal membranes, so that distinction between control Type I and Type II conformations was eliminated and a form with intermediate characters generated. It is proposed that, in producing these altered forms, the uncoupling agents are acting by suppressing the control functional states of the mitochondria. At the end of the uncoupler treatment all alterations were shown to be reversible, i.e. in cells transferred back to normal culture medium, mitochondrial profiles identical to those in control cells were again evident with time. These effects on the mitochondria could be produced whether the uncoupler was introduced externally by total cell exposure, or to the inside of the cell by microinjection. The importance of precisely defining conditions for treatments and at disrupting cell activity was evident. Thus, an uncoupler, which is a weak acid, proved to be more effective in whole cell treatments if applied at a pH near to it pKa - so ensuring its penetration across the outer cell membrane.


Mechanical tension produced by nerve cells in tissue culture.

Evidence is presented that (a) the growth cone of cultured neurons can exert mechanical tension, and (b) that the direction of advance of the growth cone is determined by the tension existing between it and the rest of the cell. (a) The evidence that growth cones can pull comes from a vectorial analysis of the outlines of individually isolated sensory neurons. The angles formed in these outgrowths are very close to those of tension-generated networks anchored at their free ends and these values are restored shortly after an experimental displacement. The relative mechanical tension on each segment of an outgrowth can be calculated by standard methods and is found to decrease at each branch point. It appears to be correlated with the diameter of the fibre so that thicker fibres maintain more tension than thinner ones. (b) The influence of tension on the direction of advance of the growth cone is shown by 2 kinds of experient. If a growing neurite is pulled to one side with a microelectrode then the direction of its advance is changed immediately according to the new stress. If the mechanical tension on the growth cone of a neurite is released by amputation or displacement the growth cone is found to have a high probability of branching shortly afterwards. The ability of the growth cone to exert tension is discussed in relation to evidence that microspikes have contractile properties and in terms of the distribution of microfilaments within the neurite. It is suggested that the exertion of tension by a growth cone could serve to guide the neurite along paths of high adhesivity both in vitro and in vivo.


Interpolation of microtubules into cortical arrays during cell elongation and differentiation in roots of Azolla pinnata.

Longitudinal sections of roots of Azolla pinnata R. Br. were prepared for electron microscopy so that cortical microtubules could be counted along the longitudinal walls in cell files in the endodermis, pericycle, and inner and outer cortex, and in sieve and xylem elements. With the exception of the xylem, where there are no transverse cell divisions, each file of cells commences with its initial cell and then possesses a zone of concomitant cell expansion and transverse cell division, followed, after completion of the divisions, by a zone of terminal cell differentiation. The cells augment their population of cortical microtubules as they elongate and divide, showing a net increase of up to 0.6 micron of polymerized microtubule length per min. Two main sub-processes were found: (i) When a longitudinal wall is first formed it is supplied with a higher number of microtubules per unit length of wall than it will have later, when it is being expanded. This initial quota becomes diluted as the second sub-process commences. (ii) The cells interpolate new microtubules at a rate which is characteristic of the cell, and, in the endodermis, of the face of the cell, while the cell elongates. Most cell types thus maintain a set density of cortical microtubules while they elongate and divide. Comparisons of endodermal cells in untreated controls, and roots that had been treated with colchicine, low temperature, or high pressure indicate that the initial quota of microtubules, and the later interpolations, and differentially sensitive to microtuble perturbations. Three types of behaviour, all related to changes in the cell walls, were noted as cortex, xylem and sieve element cells entered their respective phases of cell differentiation. The cortical cells expanded in all dimensions, and the interpolation of microtubules diminished or ceased. The sieve elements continued to elongate, and interpolated at a high rate, reaching unusually high densities of microtubules when the cell walls were being thickened. During this period a net increase of 2.0 micron of polymerized microtubule length per min was calculated. Thereafter interpolation ceased and the density of microtubules declined. The sample applied to developing xylem except that, because wall-thickening is localized rather than widespread, the rise and subsequent fall in the density of microtubules was less marked. The data are discussed in relation to the participation of microtubules in wall deposition and to the hypothesis that cortical microtubules arise in discrete zones along the edges of cells.


Fine structure of meiotic prophase chromosomes and modified synaptonemal complexes in diploid and triploid Rhoeo spathacea.

The synaptonemal complex (SC) in the diploid Rhoeo consists of 2 amorphous lateral elements, each about 46.0 nm thick, and one amorphous central element about 30.0 nm thick. The central region is about 115.0 nm wide. SC in the triploid have essentially the same dimensions as those of the diploid; both lateral (46.0 nm) and central (30.0 nm) elements are amorphous, and the central region is about 117.5 nm wide. The coil, observed in both diploid and triploid, is a modified short segment of SC with several twists at the end of a synapsed bivalent that is attached to the nuclear membrane. Serial sections in a diploid cell reveal that a coil extends inwards about 3.5 micron from the nuclear membrane and makes a complete turn at a distance of every 0.5 micron. There is a correlation between the modified ends of SC and terminal chiasmata in Rhoeo. The coils might have a positive role in the process of crossing over, or alternatively might be involved in ring formation by holding chromosome ends together while chiasmata are not involved. SC are present in chromocentres of both diploid and triploid. Chromocentres in diploid and triploid are indistinguishable, and appear to be formed from the aggregation of pericentromeric heterochromatin as a result of translocations which occured close to the centromeres. 3-dimensional hypothetical pachytene configuration of the diploid is presented.


Probing the free space within rat and chicken chromatin with active and passive probes.

The cavity systems within chicken erythrocyte nuclei and rat liver nuclei were compared using passive probes of radioactive glycogen and active probes of nuclease-armed-glycogen. The passive probe curves have a form that indicates that they are due to passive occupation of spaces and not due to the effects of a limiting membrane. The technique of probing nuclei with glycogen armed with a small enzyme is described. The chicken erythrocytes appeared to have 11-15-nm and 4-5-nm cacity systems similar to those we have previously reported in rat nuclei. Evidence is presented to show that the bridge DNA is enclosed within the 4-5 nm cavities in both rat liver and chicken erythrocyte nuclei. Minor differences between the rat liver and chicken erythrocyte nuclear cavity systems are noted in the region of 5-8 nm. A relatively mild procedure is described for preparing chicken erythrocyte nuclei.


[Complex hand injuries. Therapeutic management (author's transl)].

Defined by severe injuries of several digital structures and by lesions of several axes, complex hand injuries raise numerous problems of management. The activity of the unit "S.O.S. Hand-Reimplantation" of the Boucicaut Hospital petmitted us to determine the various clinical and socio-professional aspects. In the first part of this article, a statistical study permitted us to define the classes, types and prognosis. In the second part, the repair of each digital structure is considered (skin, bone, joint, extensors, flexors, nerves, vessels) in the light of a complex hand injury. The role of the covering skin in the quality of the results seems very important. The long-term results, their socio-professional consequences, thus permit one to draw up a therapeutic management which aims to repair the maximum number of lesions during the first stage of the operation. The interest of microsurgical repairs of the vessels and nerves requires operation of these complex hand injuries as an emergency, which requires appropriate surgical facilities.


[Aneurysms of the superior mesenteric artery and of its branches. Report of three cases (author's transl)].

The authors report three cases of atheromatous aneurysm revealed by a complication (e.g. rupture, thrombosis, peripheral embolisation) and propose an etiological, physio-pathological, clinical and therapeutic study of aneurysms of the superior mesenteric artery. They emphasise the advantages of early diagnosis leading to arteriography, which alone permits appropriate surgical treatment.


[Fascicular nailing of the femur and tibia. 14 years' experience. Report of 275 cases (author's transl)].

The use of the fascicular four-pin nail has been introduced to correct certain inadequacies revealed by the rigid nailing according to Kuntscher's method; made up of four tiny pins soldered at each end, it fits the curve of the bone; its elasticity allows a much greater resistance to repeated strain as compared to other nails; an experimental study which compares the stability of fresh femurs cut then nailed according to different methods, reveals a definite superiority for the fascicular nail. The clinical use for 14 years (275 nailings among which 92 cases werefresh closed fractures of the femur) confirms that such a method provides the advantage of nailing without reaming as well as the possibility of immediate weight bearing ambulation for most patients (75% in the cases of resh femur or tibia fractures).


[Pulmonary hydatidosis in the child (author's transl)].

In general, pulmonary hydatidosis supposes 22% of the cases treated in a general surgery unity and 4.9% correspond to infantile hydatidosis (98 cases). The authors establish an anatomico-pathological classification of the cyst and make a comparative study with adults. The authors then expound on the different types of complications after the differents treatments used to treat hydatid disease since 1952. Post-operatory morbidity is 4.7% and mortality of 0.9%. These percentages are related to the anatomico-pathological type of the cyst.


[Idiopathic congenital dilatation of the common bile duct and pregnancy. Report of one case, reflexions and comments (author's transl)].

Congenital idiopathic dilatation of the common bile duct, called commonly and incorrectly congenital cyst of the common bile duct, is sometimes diagnosed during pregnancy. The latter may be the source of severe complications. The disease should thus be treated rapidly, even if the pregnancy is at a late stage. In a case of this type we carried out surgical treatment in two stages: firstly simple external drainage of the common bile duct and of the gall bladder and only after labour has been brought to term by Caesarian section, for breech presentation, was a cystojejunostomy carried out on a Y shaped jejunal loop.


[Experimental study of the permeability of the fallopian tubes in the rabbit after division of the isthmus and microsurgical anastomosis (author's transl)].

The poor results of traditional reconstructive surgery of the Fallopian tubes have led the authors to try the possibilities of microsurgery in tubal sterility. The experimental animal chosen was the rabbit owing to its similarities with the Fallopian tube in women. After division of the isthumus, the tube was repermeabilised with a 10.0 single nylon thread under the operating microscope. A series of 11 rabbits were then coupled one mont after the operation. The pregnancy rate was 55%. This figure was much better than those obtained in the literature by non-microsurgical technics. One may hope to improve the results further by less traumatic surgery, better asepsis, and better control of fertility.


The quantitative analysis of 1-alpha-acetylmethadol and its principal metabolites in biological specimens by gas chromatography-chemical ionization-multiple ion monitoring mass spectrometry.

1-alpha-acetylmethadol (LAAM) is a new drug under development for the treatment of heroin dependence. A new analytical  method applicable to the accurate biodispositional study of the drug and its metabolities is described and critically discussed in this report. The procedure involves sample preparation and direct organic solvent extraction using eta-butyl chloride, amide derivatization by molecular rearrangement, and gas chromatography-chemical ionization mass spectrometry-selected ion monitoring, with methane as the carrier and ammonia as reagent gases. Deuterated (d3 stable isotopes of LAAM and its metabolites are used as internal standards. The method is free from qualitative interferences and has quantitative sensitivity to 5 ng/ml for 2.0 ml samples with 10-15% accuracy and precision in the range 5-100 ng/ml; and 2-5% at concentrations up to 750 ng/ml. Specimens of plasma, whole blood, urine, bile, brain, liver, and other visceral samples have been successfully analyzed, as well as in vitro preparations such as hepatic microsomes. By appropriate data processing, the method lends itself to routine analysis and high volume work; even manually the method is capable of at least 50 samples per week. A simplified procedure for the analysis of LAAM and its metabolites in urine only is also presented and discuet up and use the methods.


Determination of paraquat in marijuana by reversed-phase paired-ion high performance liquid chromatography.

A sensitive and selective method is described for the quantitative determination of paraquat in marijuana. Paraquat is extracted from finely ground plant material with hydrochloric acid with sonification, and the resulting acidic solution is extracted with chloroform:isopropanol (9:1) and evaporated to dryness. The residue is reconstituted with aqueous phosphate buffer pH 7.0; the solution is passed through a C-18 SEP-PAK TM and is analyzed with high performance liquid chromatography, using a reversed-phase column and an "ion pairing" reagent in the mobile phase. The recovery of paraquat in laboratory-spiked material varied from 90-97%. Results obtained with confiscated, field-sprayed marijuana by the procedure described were in excellent agreement with those obtained with a well-established ultraviolet procedure. The calculated limit of detection with this method is 2 ng of paraquat.


Trenbolone acetate and trenbolone: trace analysis in animal chow, wastewater and human urine by high pressure liquid chromatography and electron capture gas chromatography.

Analytical methodology is described for determining residues of the synthetic anabolic steroid trenbolone acetate (TBA) and its hydrolysis product trenbolone (TBOH) in admixture in animal chow, human urine, and wastewater. Benzene extracts of the substrates are subjected to liquid-liquid partitioning, further cleanup on a column of silica gel, and direct analysis by high pressure liquid chromotography or derivatization with pentafluoropropionic anhydride and analysis by electron capture gas chromatography. Satisfactory recoveries were obtained with both compounds from all three substrates. Residue levels of TBA and TBOH as low as 0.32 and 0.04 ppm, respectively, could be detected in chow; about 0.6 ppb of each compound could be detected in urine and wastewater. Thin layer chromatographic behavior of the two compounds in 7 solvent systems and other ancillary analytical data are also presented.


Derivative formation in the chromatographic analysis of food additives.

The use of derivatization in the analysis of food additivies by chromatographic means has been reviewed. The large majority of these derivatization techniques are employed to facilitate the gas-liquid chromatographic quantitation of various food additives. Silylation, alkylation, acylation, as well as transesterification, saponification, and chemical decomposition techniques are discussed. The review includes procedures for the analysis of emulsifiers and stabilizers, artificial sweeteners, antioxidants, preservatives, gums, and waxes, and draws in part, from work conducted in the authors' laboratory.


Metabolic clearance rates of isohormones of human growth hormone in man.

The charge isomers of human GH (/GH), isohormones C, D, and E, which result from limited proteolytic cleavage exhibit enhanced biological activity in the rat and in man compared to the intact polypeptide and most abundant form, isohormone B. The mechanism leading to enhanced activity is unknown. To examine the possibility that different in vivo metabolism may represent one such mechanism, the MCRs of radioiodinated hGH-B, -C, and -D were measured in seven normal adults. Significant differences in metabolic clearance were found between isohormones (hGH-B, 108.4; hGH-C, 67.9; hGH-D, 55.7 liters/m2-day). It is concluded that in man, the enzymatically cleaved hGH isohormones are cleared more slowly than hGH-B. Slower metabolism may be a factor responsible for the enhanced biological activity of proteolytically cleaved hGH isohormones.


Failure of estrogen-induced discharge of luteinizing hormone in lactating women.

Pituitary-ovarian relationships were studied in seven lactating women by measuring the basal plasma concentrations of pituitary and ovarian hormones and their responses to an estrogen provocation test at 7, 30, and 100 days after delivery. The results were compared to a similar group of seven women who did not breast feed. The first ovulation occurred in five of the nonlactating women beteen 43-87 days after delivery, as judged by the urinary excretion of total estrogen and pregnanediol. In all lactating women, ovarian cyclicity was suppressed for at least 150 days after delivery or until weaning. The basal concentration of PRL in lactating women was significantly higher than in the nonlactating women at all three times measured. At 30 and 100 days, the concentration of estradiol was significantly lower in the lactating women, although the basal concentrations of FSH were similar in the two groups. After an injection of 1 mg estradiol benzoate, the concentrations of FSH and LH in plasma were suppressed to a greater extent in lactating than in nonlactating women. In addition, fewer of the lactating group (one of seven and none of seven at 30 and 100 days, respectively) than the nonlactating group (two of seven and five of seven) subsequently showed a rise in the concentration of LH 58--96 h after the estrogen injection (positive feedback). These results suggest that during lactation the hypothalamic-pituitary system is more sensitive to the negative feedback and relatively insensitive to the positive feedback of estrogen.


Roles of estradiol and progesterone in eiliciting the midcycle luteinizing hormone and follicle-stimulating hormone surges.

The positive feedback effects of estradiol (E2) and progesterone (P) on LH and FSH release were studied under novel experimental conditions in three women of reproductive age who had undergone oophorectomy and received uninterupted E2 replacement by subdermal implants. Basal serum E2 levels were in the midfollicular phase range, while LH and FSH levels were normal or slightly elevated. Each volunteer underwent seven experiments at 2- to 4-week intervals, receiving im injections of increasing amounts of estradiol benzoate (E2B) alone and in combination with P. The time and dose of P (administered via P-impregnated polysiloxane intravaginal rings) were varied. In two of the seven experiments, P was given without E2B injections. In all three subjects, increasing serum E2 levels mimicking the preovulatory E2 peak were followed by a surge of LH but not of FSH. However, when serum P levels rose after an increase in serum E2 concentrations had occurred, the LH surge occurred earlier and was accompanied by an FSH peak. When serum P levels rose before serum E2 concentrations had risen or when P levels increased without a rise in serum E2, neither a serum LH nor FSH peak was observed. When administered concomitantly, E2B and P suppressed FSH but not LH levels, while P alone did not affect serum LH or FSH concentrations. These data indicate that an acute rise in serum E2 is a necessary condition for the midcycle LH and FSH surges, that P facilitates or blocks the positive feedback response of gonadotropin release in a time-dependent manner, and that P is required for the preovulatory FSH peak.


Aluminum uptake by the parathyroid glands.

Aluminum-containing drugs are used extensively to bind dietary phosphate and as antacids, but little is known about toxicity and tissue uptake of ingested aluminum. Aluminum concentrations were measured by neutron activation analysis in tissues taken from hyperparathyroid and normal human subjects and from rats. The parathyroid glands contained significantly more aluminum per unit mass than did thyroid or cervical muscle. The concentration of aluminum in the parathyroids appears to be linearly related to dietary aluminum intake.


A solid phase, sandwich-type radioimmunoassay for antithyroglobulin: elimination of false positive results and semiquantitative measurement of antithyroglobulin in the presence of elevated thyroglobulin.

Thyroid disorders can be associated with elevated concentrations of serum antithyroglobulin antibodies (anti-Tg) and/or thyroglobulin (Tg), but none of the available anti-Tg assays deals with anti-Tg measurements in the presence of abnormally high Tg levels. The competitive binding radioassay produces falsely elevated values for anti-Tg if serum Tg is elevated and either falsely elevated or depressed values if both Tg and anti-Tg are abnormally high. The falsely elevated anti-Tg values can be identified by measuring the formation of Tg[125I]anti-Tg complexes in the supernatant of the anti-Tg assay (supernatant assay). For screening purposes, we modified the original anti-Tg RIA into a solid phase, sandwich-type RIA. Anti-Tg in serum or standard is first bound to plastic cups coated with Tg and then quantitated by binding of [125I]Tg. This assay has a detection limit of 2 U/ml serum, intra- and interassay coefficients of variation of 9--15%, and a normal range of less than 2 U/ml. When sera with normal Tg concentrations were analyzed, the results for anti-Tg obtained by the competitive binding RIA and the new sandwich RIA were comparable as far as positives and negatives were concerned, and the numerical values for positive sera correlated moderately well (r = 0.79); the sandwich assay, in general, gave lower values for anti-Tg. The major advantages of the sandwich anti-Tg RIA are the elimination of false positive results and its applicability to sera containing high levels of both Tg and anti-Tg. In the latter case, the results indicate the level of free anti-Tg present, as opposed to antibody present in the form of Tg-anti-Tg complexes.


Plasma vasopressin and human neurophysins in physiological and pathological states associated with changes in vasopressin secretion.

Using sensitive specific RIAs for vasopressin (AVP) and the two major human neurophysins, the relationship between AVP and the individual human neurophysins was investigated in man by measuring changes in plasma concentrations in physiological and pathological states known to be associated with changes in AVP secretion. Dehydration, water loading, and hemorrhage produced small but significant changes in plasma AVP concentrations without changes in the individual human neurophysins. In response to the stimulus of cigarette smoke inhalation, large parallel changes in plasma AVP and human neurophysin I (HNPI) levels were seen without change in plasma human neurophysin II (HNPII) levels. In the pathological states of diabetes insipidus and the syndrome of inappropriate antidiuretic hormone secretion,the observations more strongly supported a specific association between AVP and NHPI. In eight patients with central diabetes insipidus, plasma AVP and HNPI levels were low or undetectable, while plasma HNPII levels were normal. There was a clear distinction of both plasma AVP and HNPI levels in patients with central diabetes insipidus and those in patients whti nephrogenic diabetes insipidus. In 14 patients with the syndrome of inappropriate antidiuretic hormone secretion due to causes other than ectopic AVP production from tumors, plasma AVP and HNPI levels were elevated or normal, while plasma HNPII levels were normal. There was a highly significant positive correlation (r = 0.99) between plasma AVP and HNPI levels in these patients, with a 1:1 molar ratio. These data suggest that the secretion of AVP and HNPI in man are functionally related, while the secretion of HNPII is independent of AVP secretion.


Renal clearance of estriol and its conjugates in normal and abnormal pregnancies.

Renal clearance of estriol (E3), E3-3-sulfate (E3S), E3-16-glucuronide (E316G), E3-3-glucuronide (E33G), and E3-3-sulfate-16-glucuronide (E3SG) has been measured in 13 normal and 17 abnormal pregnancies between the 33rd and 40th weeks of gestation. The methodology involved a chromatographic separation on a celite column in the presence of tritiated tracers, enzymic hydrolysis of the conjugates, and measurement of the E3 moiety by a specific RIA. Preeclampsia (eight patients) was characterized by a significant decrease of renal clearance for all conjugates except E33G. In contrast to that pattern, a patient with cholestatic icterus had normal clearances except for E33G, which was reduced to less than 15% of its normal mean value. Administration of ampicillin to a pregnant woman induced an important decrease of all E3 clearances, especially for E33G which decreased to nearly 1% of its initial value; normal clearances were resumed within a week after the end of the treatment. In a small number of complicated pregnancies, E3 clearances were normal. A significant correlation between the renal clearance of E316G and that of urea and creatinine has been demonstrated.


The effect of angiotensin II and saralasin on 18-hydroxy-11-deoxycorticosterone production by isolated human adrenal glomerulosa cells.

To assess the role of angiotensin II (AII) in regulating 18-hydroxy-11-deoxycorticosterone (18-OHDOC) secretion in man, isolated human adrenal glomerulosa cells were incubated with AII and/or its competitive antagonist, saralasin. AII 2.4 X 10(-8) M) elicited an 80% increase in 18-OHDOC levels as well as similar increases in aldosterone, 18-hydroxycorticosterone, and corticosterone (P less than 0.01). Saralasin (10(-8) M) caused a partial but significant inhibition of AII-stimulated 18-OHDOC production, while 10(-6) M saralasin blocked AII-stimulated steroidogenesis completely. In addition, both concentrations of saralasin caused 10--30% decrements in basal steroid levels. The direct AII effect on 18-OHDOC secretion and the antagonistic effect of saralasin on both exogenous and endogenous AII-stimulated steroidogenesis, documented in these experiments, indicate that the increase in 18-OHDOC levels after sodium restriction reported in man is probably mediated by the renin-angiotensin system. Furthermore, because high concentrations of saralasin did not increase aldosterone secretion, the partial agonist properties of saralasin in vivo in man may not be due to a direct effect on the glomerulosa cell.


Metabolic effects of glucose, mannose, galactose, and fructose in man.

The effects of various hexoses upon immunoreactive insulin (IRI) secretion, glucose disposal, and gastric inhibitory polypeptide (GIP) release have been compared in 10 normal nonobese men. Rapid iv infusion (0.5 g/kg in 3 min) of D-mannose resulted in significant ITI release, the peak levels approaching those after D-glucose infusion. D-Galactose, however, was ineffective. The 60-min urine excretions of mannose, galactose, and glucose were 35 +/- 7%, 16 +/- 4%, and 5.5 +/- 0.7% (mean +/- SEM) of the administered dose, respectively. All subjects also received 50 g oral glucose, mannose, galactose, and fructose on different days, each followed by an iv glucose infusion 30 min later. The ingestion of glucose or galactose resulted in a similar increment of GIP (P less than 0.01), followed by a similar increment in the IRI response to iv glucose. Furthermore, the glucose disposal rate increased 2.5-fold compared to that after iv glucose alone (P less than 0.001). However, oral msnnose or oral fructose caused no significant GIP release, yet the IRI response to a subsequent iv glucose load was moderately augmented after oral mannose or oral fructose when compared to iv glucose alone. In addition, there was a similar enhancement of glucose disposal of the iv glucose load after both oral mannose and oral fructose (P less than 0.01). From these studies we conclude that 1) galactose does not elicit IRI secretion per se, yet, like glucose, potentiates GIP and IRI secretion; 2) mannose, despite weak transport across gut or kidney, evokes significant betacytotropic effects; and 3) mannose- and fructose-induced enhancement of glucose disposal might be mediated by a factor(s) other than GIP.


Acute effects of aminoglutethimide on testicular steroidogenesis in normal men.

Aminoglutethimide (AG), a known adrenal inhibitor, was administered acutely to normal men in order to study its effects on testicular steroidogenesis. Sixteen subjects between the ages of 21--30 yr received either placebo or 1250 mg AG in divided doses during a 24-h period. To reduce the contribution of adrenal steroids, adrenal function was inhibited in both groups of men by the administration of dexamethasone (2 mg) on the night of the experiment. As a result, mean morning plasma cortisol levels fell to less than 2 micrograms/100 ml. AG blunted the normal diurnal rise in testosterone, which was observed in men receiving placebo, and significantly suppressed the levels of this androgen at 0700 and 0900 h. Estradiol concentrations fell to a greater extent than those of testosterone. The differences between the placebo and drug treatment groups were significant at all time points except 1900 h. A pattern similar to that of estradiol was observed for plasma estrone. When the overall effect of AG administration was examined by analysis of variance, the differences in the levels of all three steroids produced by treatment were highly significant (P less than 0.01 to less than 0.001). After the inhibition of testosterone and estradiol levels, LH and FSH concentrations were significantly (P less than 0.01 and P less than 0.001, respectively) higher in men receiving AG than in those given placebo. However, the data exhibited a large variance due to pulsatile gonadotropin secretion. These observations suggested that AG induces an acute inhibition of testicular steroidogenesis and probably also of the aromatization of testosterone to estradiol.


Localization of aldosterone-producing adenoma by computed tomography.

Abdominal computed tomography (CT) was performed on nine patients with primary aldosteronism in an attempt to evaluate the utility of this noninvasive procedure in localizing aldosterone-producing adenomas. Confirmation of the diagnosis of primary aldosteronism was made by demonstrating elevated urinary aldosterone excretion, low PRA, and failure of plasma aldosterone to fall after acute saline load. Each patient had diagnostic lateralizing adrenal venous sampling and adrenal venography before unilateral adrenalectomy. The CT scan correctly predicted unilateral adenoma in the four patients whose tumors measured the largest in diameter at surgery. Bilateral tumors measuring 0.8 and 1.2 cm on scan (at or below the resolution capabilities of our scanner) were falsely predicted in two patients. The CT scan failed to identify an adrenal abnormality in three patients whose tumors measured 0.9, 1.0, and 1.0 cm in greatest diameter. It is concluded that at its current state of precision, the CT scan is of diagnostic utility in primary aldosteronism when a large adenoma is present. In our patients, the adrenal venogram and CT scan were equally accurate. The sampling of adrenal venous blood for aldosterone and cortisol remains the gold standard for localization of unilateral adenoma.


Direct radioiodination of estradiol for a sensitive radioimmunoassay.

17 beta-estradiol (E2) was iodinated with the chloramine-T method. The 125I-labelled material was purified with thin-layer chromatography. The major fraction was applied to a radioimmunoassay with an antiserum against estradiol-6-(0-carboxymethyl)oxime-BSA. The sensitivity of the assay was comparable to assays with 3H-E2 or 125I-histamine-E2 as tracers. The working antiserum dilution (1:1 000 000) was the same with 125I-E2 and 3H-E2 but lower than that with 125I-histamine-E2. The results indicate that iodination of the A-ring of estrogens will not cause significant reduction of the immunoreactivity when combined with an antiserum to a B-ring conjugate.


The role of thyronine in thyroid hormone metabolism.

Thryonine (T0) has been identified in human urine using gas chromatography-mass fragmentography (G.C.M.F.). In 22 normal individuals urinary T0 concentration was found to range between 8--25 nmol/24h. Assuming the mean normal thyroxine (T4) production rate to be approximately 100 nmol/24h, our findings indicate that less than 20% of this could be accounted for as urinary T0 excretion, thus supporting earlier findings that the peripheral metabolism of T4 is not limited solely to deiodination.


Pseudomonas paucimobilis from a leg ulcer on a Japanese seaman.

Pseudomonas paucimobilis was isolated in pure culture from an ulcer on the leg of a Japanese seaman while in an Australian port. A description of the isolate is given. This may be the first report of a human infection in which this recently characterized species is implicated as a pathogen.


Simplified technique for sonication and processing of dental plaque samples.

A simplified method for processing dental plaque samples was devised and compared to previously used methods. Analysis of 36 nonstandardized subgingival plaque samples from various states of periodontal health and disease and 12 standardized supragingival plaque samples demonstrated that there was no significant difference between the recovery offered by the two techniques. Comparable recovery, increased convenience, and adaptation to the clinical setting suggests that implementation of this simplified technique may be of great value.


Broth dilution minimum inhibitory concentrations: rationale for use of selected antimicrobial concentrations.

A microdilution susceptibility testing procedure utilizing selected, clinically relevant concentrations of a large number of antimicrobial agents is described. A qualitative code designed to facilitate interpretation of quantitative results is coupled with each antimicrobial concentration. Both the antimicrobial concentrations selected for testing and the assigned codes are based on published data regardling attainable antimicrobial levels in serum and urine.


Survival of anaerobic bacteria in common laboratory diluents.

The survival of six species of anaerobic bacteria was studied in simple or commercially available diluents. Bacteroides fragilis and Fusobacterium nucleatum showed excellent survival in all diluents including distilled water. Fusobacterium mortiferum survived well in all diluents except water and water supplemented with 0.1% gelatain. Clostridium perfringens survived best in phosphate-buffered saline with gelatin. Peptococcus asaccharolyticus required gelatin added to the basic diluent, and Streptococcus intermedius showed excellent survival only in minimal essential medium with gelatin. These diluents could provide effective and economical alternatives to more complex and costly diluents often used in work with anaerobic bacteria.


Recovery of Angiostrongylus cantonensis from cerebrospinal fluid of a child with eosinophilic meningitis.

Viable Angiostrongylus cantonensis was recovered from the cerebrospinal fluid of a 17-month-old boy with eosinophilic meningitis. Neurological findings were minimal, and the child had an uneventful recovery.


Fasle-positive macroscopic appearance of blood cultures in sorbitol-containing hypertonic medium.

Inability to rely on macroscopic examination as an aid in identifying positive blood cultures was encountered when a hypertonic medium containing sorbitol was tested in a comparative study with an isotonic blood culture medium.


Selective medium for Corynebacterium equi isolation.

The development of a selective medium for the isolation of Corynebacterium equi is described. The medium has been used to examine fecal samples from 127 horses of which 90 have been found to carry the organism.


Further studies of the cellular fatty acid composition of Legionnaires disease bacteria.

The cellular fatty acid composition of 36 strains of the Legionnaires disease bacterium was determined by gas chromatography after growth on different media. The fatty acid profile of each strain was essentially identical on each medium and was characterized by large amounts (greater than 68%) of branched-chain acids.


Insulin binding to monocytes in trained athletes: changes in the resting state and after exercise.

Insulin binding to monocytes was examined in trained athletes (long distance runners) and in sedentary control subjects in the resting state and after 3 h of exercise at 40% of maximal aerobic power. At rest, specific binding of 125-I-insulin to monocytes was 69% higher in athletes than in sedentary controls and correlated with maximal aerobic power. The increase in insulin binding was primarily due to an increase in binding capacity. During acute exercise, insulin binding fell by 31% in athletes but rose by 35% in controls. The athletes had a smaller decline in plasma glucose and a lower respiratory exchange ratio during exercise than did controls. We conclude that physical training increases insulin binding to monocytes in the resting state but results in a fall in insulin binding during acute exercise. Changes in insulin binding in athletes thus may account for augmented insulin sensitivity at rest as well as a greater shift from carbohydrate to fat usage during exercise than is observed in untrained controls.


Effect of intact parathyroid hormone on hepatic glucose release in the dog.

The liver has been shown to remove parathyroid hormone (PTH) from its arterial circulation by a mechanism that is selective for the intact form of the peptide (PTH 1-84). The present studies demonstrate that PTH has biologic effects on the liver in vivo. Bovine PTH 1-84 stimulated hepatic glucose release in dogs with indwelling hepatic vein catheters from basal values of 31+/-8 to 68+/-9 mg/min per kg after bolus injections of PTH. The effect on hepatic glucose release was apparent by 5 min and persisted for the 80 min of observation. The NH(2)-terminal PTH fragment (syn b-PTH 1-34) had no effect. Bovine PTH 1-84 administered in doses designed to produce circulating levels of immunoreactive PTH similar to the endogenous levels observed in uremic dogs also increased the incorporation of (14)C from infused [(14)C]alanine into glucose, and increased estimated hepatic uptake of both chemical and [(14)C]alanine, while increasing hepatic glucose release. Thus, administration of "physiologic levels" of b-PTH 1-84 stimulated hepatic glucose release in part through increased gluconeogenesis in vivo, whereas syn b-PTH 1-34 had no demonstrable effect. Circulating levels of insulin rose after PTH administration, an increase which presumably represents a secondary response to the rise in glucose release. These results suggest that the liver is a target organ of PTH, and that PTH might potentially alter carbohydrate metabolism during hypersecretion. They also suggest that hepatic uptake of PTH may be related in part to production of a specific biologic effect rather than just simple peptide degradation.


Modification of hemoglobin H disease by sickle trait.

The rarity of hemoglobin (Hb) H disease in combination with sickle trait may be due in part to the absence of actual Hb H in individuals who, nonetheless, have inherited the deletion of three alpha-globin genes. We describe here a boy with persistent microcytic, hypochromic anemia despite adequate iron stores, who exhibited splenomegaly with a normal reticulocyte count and only rare inclusions in circulating erythrocytes. Starch gel electrophoresis and isoelectric focusing at age 5 yr showed 21% Hb S, persistent Hb Bart's, but no Hb H. Recticulocyte alpha/non-alpha globin chain synthesis ratio was 0.58 at age 5. The mother (Asian) had laboratory evidence of alpha-thalassemia trait and the father (Black) had sickle trait. The nature of alpha-thalassemia in this patient was investigated both by liquid hybridization and by the Southern method of gene mapping, in which DNA is digested with restriction endonucleases and the DNA fragments that contained the alpha-globin structural gene identified by hybridization with complementary DNA. The patient had only one alpha-globin structural gene, located in a DNA fragment shorter than that found in normal or alpha-thalassemia trait individuals, but similar to that present in other patients with Hb H disease. Morphologic studies of bone marrow by light and electron microscopy revealed erythroid hyperplasia with inclusions in polychromatic and orthochromatic erythroblasts, suggesting early precipitation of an unstable hemoglobin. The lack of demonstrable Hb H may be the result of both diminished amounts of beta(A) available for Hb H formation (since one beta-globin gene is beta(S)) and the greater affinity of alpha-chains for beta(A) than beta(S)-globin chains leading to the formation of relatively more Hb A than Hb S. The presence of a beta(S) gene may thus modify the usual clinical expression of Hb H disease.


Mechanisms of gas exchange abnormality in patients with chronic obliterative pulmonary vascular disease.

We have examined the mechanisms of abnormal gas exchange in seven patients with chronic obliteration of the pulmonary vascular bed secondary to recurrent pulmonary emboli or idiopathic pulmonary hypertension. All of the patients had a widened alveolar-arterial oxygen gradient and four were significantly hypoxemic with arterial partial presssures of oxygen less than 80 torr. Using the technique of multiple inert gas elimination, we found that ventilation-perfusion (VA/Q) relationships were only minimally abnormal with a mean of 10% (range, 2--19%) of cardiac output perfusing abnormal units. These units consisted of shunt and units with VA/Q ratios less than 0.1. In addition, the dead space was found to be normal in each patient. There was no evidence for diffusion impairment, and the widened alveolar-arterial oxygen gradient was completely explained by VA/ inequality. Significant hypoxemia occurred only when VA/Q inequality was combined with a low mixed venous oxygen content.


Activation of human factor VII in plasma and in purified systems: roles of activated factor IX, kallikrein, and activated factor XII.

Factor VII can be activated, to a molecule giving shorter clotting times with tissue factor, by incubating plasma with kaolin or by clotting plasma. The mechanisms of activation differ. With kaolin, activated Factor XII (XII(a)) was the apparent principal activator. Thus, Factor VII was not activated in Factor XII-deficient plasma, was partially activated in prekallikrein and high-molecular weight kininogen (HMW kininogen)-deficient plasmas, but was activated in other deficient plasmas. After clotting, activated Factor IX (IX(a)) was the apparent principal activator. Thus, Factor VII was not activated in Factor XII-,HMW kininogen-, XI-, and IX-deficient plasmas, but was activated in Factor VIII-, X-, and V-deficient plasmas. In further studies, purified small-fragment Factor XII(a) (beta-XII(a)), kallikrein, and Factor IX(a) were added to partially purified Factor VII and to plasma. High concentrations of beta-XII(a) activated Factor VII in a purified system; much lower concentrations of beta-XII(a) activated Factor VII in normal plasma but not in prekallikrein or HWM kininogen-deficient plasmas. Kallikrein alone failed to activate partially purified Factor VII but did so when purified Factor IX was added. Kallikrein also activated Factor VII in normal, Factor XII-, and Factor IX-deficient plasmas. Purified Factor IX(a) activated partially purified Factor VII and had no additional indirect activating effect in the presence of plasma. These results demonstrate that both Factor XII(a) and Factor IX(a) directly activate human Factor VII, whereas kallikrein, through generation of Factor XII(a) and Factor IX(a), functions as an indirect activator of Factor VII.


Pituitary gland: site of short-loop feedback for luteinizing hormone in the rabbit.

The development of a species specific radioimmunoassay for rabbit luteinizing hormone (LH) has permitted the direct demonstration of LH feedback control of LH secretion (short-loop feedback control). In previous studies we showed that small bolus injections of human LH (hLH) intravenously administered to castrate female rabbits suppressed rabbit LH for 20-30 min. Human LH had no effect on rabbit follicle-stimulating hormone secretion. This control system was responsive to amounts of hLH estimated to be present in blood of eugonadal men and women. These studies were designed to determine whether this feedback control was exerted at a pituitary or hypothalamic level. Two groups of studies were carried out: (a) in vivo studies: Rabbit LH was quantified in the blood of castrated female New Zealand White rabbits receiving either constant hLH perfusion (2.75 IU/min) or saline perfusion, plus a bolus injection of 0.5, 6, or 20 mug of gonadotropin-releasing hormone (GnRH). Human LH decreased the response to 6 and 20 mug of GnRH by 31 and 36%, respectively, and abolished the response to 0.5 mug, GnRH. (b) in vitro studies: Rabbit pituitary slices were incubated in the presence of medium alone, medium plus hLH (25 mIU/ml), medium plus GnRH (20 mug/ml), and medium plus both GnRH and hLH. hLH decreased basal rabbit LH release into the medium and abolished GnRH-stimulated rabbit LH release. hLH had no effect on rabbit follicle-stimulating hormone release. From these results we conclude that a direct and specific feedback control of LH on LH exists at a pituitary level.


Functional characterization of left ventricular segmental responses during the initial 24 h and 1 wk after experimental canine myocardial infarction.

Characterization of the temporal evolution of resting segmental function and inotropic reserve after coronary occlusion may be important in evaluating attempts to salvage ischemic but non-necrotic myocardium. Accordingly, we chronically implanted up to six pairs of pulse-transit piezoelectric crystals in the left ventricular myocardium of dogs to measure segmental wall thickness. Segments were separated into groups according to the loss of net systolic thickening (NET) at 5 min postocclusion of the left anterior descending coronary artery in awake, unsedated dogs. Group 1 included segments with NET values of 67--100+ (percent control); group 2 between 67 and 0; and group 3 less than 0 (paradoxical motion). 5 min after coronary occlusion, group 1 NET was 92 +/- 5% (SEM) although significant decreases occurred in NET in group 2 (36 +/- 4%) and group 3 segments (-33 +/- 5%). Between 5 min and 24 h after coronary occlusion, no further significant changes occurred in NET in groups 1, 2, and 3 crystals. Some segments underwent further functional deterioration between 24 h and 1 wk after left anterior descending coronary artery occlusion, although no overall change occurred in segments with mild to moderate ischemic dysfunction. Segments with NET less than 0 at 24 h, on the other hand, exhibited a reduction in aneurysmal bulging between 24 h and 1 wk from -41 +/- 10 to -23 +/- 11% (n = 12, P = 0.02). Inotropic reserve was assessed with postextrasystolic potentiation (PESP) in 14 dogs, and with infusions of dopamine (11 dogs), and isoproterenol (13 dogs). PESP was the most potent intervention and produced a significant augmentation in NET in group 2 crystals at 1, 2, 4, 6,8, and 24 h after coronary occlusion but only at 1 and 2 h in NET in group 3 crystals. Thus, following experimental coronary occlusion, the evolution of ischemic segmental dysfunction is dynamic and variable. A significant degree of inotropic reserve, as assessed by PESP, dopamine, and isoproterenol, exists in segments with moderate ischemic dysfunction for 24 h but for only 2 h after coronary occlusion in those segments with the most severe ischemic dysfunction. In addition, at least some segmental sites with mild to moderate ischemic dysfunction at 24 h deteriorate further between 24 h and 1 wk after experimental coronary occlusion.


Effect of anticonvulsant drugs on the rate of folate catabolism in mice.

An increase in folate catabolism has been suggested as the cause of the folate deficiency observed in many clinical conditions, including chronic anticonvulsant therapy. Previous studies have shown that the radioactive catabolites, excreted after an equilibration period of 3 d, consisted exclusively of folates that had been cleaved to produce pteridines and p-aminobenzoylglutamate, most of which was excreted as acetamidobenzoylglutamate. We have developed an experimental animal model using mice to determine the rate of catabolism of [3H]pteroylglutamate (folic acid) by the quantitative estimation of [3H]p-aminobenzoylglutamate and [3H]acetamidobenzoylglutamate in urine. Administration of diphenylhydantoin at three different doses (0.5, 20, and 50 mg/kg) significantly increased the rate of catabolism as measured by an increase in both the mean daily excretion and the cumulative excretion of these catabolites. Administration of intramuscular phenobarbitone on the other hand, did not affect the rate of catabolism, when compared with controls.


Site of substrate stimulation of jejunal sucrase in the rat.

To identify the site of stimulation of sucrase by a sucrose diet, changes in sucrase-specific activity of jejunal mucosa were studied after introduction of sucrose diet to carbohydrate-deprived rats. Results were correlated with simultaneous changes in villus gradients of sucrase-specific activity. Simultaneous with the introduction of sucrose diet, [(3)H]thymidine (100 muCi) was administered intravenously, and rates of cell migration measured during adaptation to the new diet. After a 72-h fast, rats fed sucrose diet for 6, 12, or 18 h showed no change in sucrase-specific activity in either whole mucosa or villus gradients. However, within 18-24 h after starting a sucrose diet, there was a marked rise in whole mucosal sucrase-specific activity above fasting values (99 +/- 14 vs. 38 +/- 4 muM glucose/min per g protein, P < 0.001) in association with the development of a region of increased activity at the lower villus (154 +/- 22 vs. 60 +/- 9 muM glucose/min per g protein, P < 0.02, but with no change in villus tip activity (56 +/- 5 vs. 46 +/- 8 muM glucose/min per g protein). Similar changes were seen in animals fed 24 h of sucrose diet after a 72-h carbohydratefree diet. Fasted animals fed sucrose diet for 36 h had increased sucrase-specific activity at the villus tip (144 +/- 11 muM glucose/min per g protein) as well as at the lower villus region, and this pattern persisted at 1 wk of sucrose diet. Maximal activity patterns for isomaltase and maltase paralleled those for sucrase, but the villus gradients for lactase were unaffected by sucrose diet. The region of maximal sucrase-specific activity always coincided with or followed the leading edge of radioactivity as determined by liquid scintillation counting. Therefore, sucrose-mediated changes in sucrase activity of the jejunal mucosa in the rat appear to be initiated at the level of the crypt epithelial cell and are expressed after a latent period of 18-24 h during which these cells mature and migrate toward the villus tip.


Erythrocyte adenosine deaminase deficiency without immunodeficiency. Evidence for an unstable mutant enzyme.

Inherited deficiency of the purine salvage enzyme adenosine deaminase (ADA) gives rise to a syndrome of severe combined immunodeficiency (SCID). We have studied a 2.5-yr-old immunologically normal child who had been found to lack ADA in his erythrocytes during New York State screening of normal newborns. His erythrocytes were not detectably less deficient in ADA than erythrocytes of ADA(-)-SCID patients. In contrast, his lymphocytes and cultured long-term lymphoid cells contained appreciably greater ADA activity than those from patients with ADA(-)-SCID. This residual ADA activity had a normal molecular weight and K(m) but was markedly unstable at 56 degrees C. His residual erythrocytes-ADA activity also appeared to have diminished stability in vivo. ADA activity in lymphoid line cells of a previously reported erythrocyte-ADA-deficient!Kung tribesman was found to contain 50% of normal activity and to exhibit diminished stability at 56 degrees C. ATP content of erythrocytes from both partially ADA-deficient individuals was detectably greater than normal (12.3 and 6.1 vs. normal of 2.6 nmol/ml packed erythrocytes). However, the dATP content was insignificant compared to that found in erythrocytes of ADA(-)-SCID patients (400-1,000 nmol/ml packed erythrocytes). The New York patient, in contrast to normals, excreted detectable amounts of deoxyadenosine, but this was <2% of deoxyadenosine excreted by ADA(-)-SCID patients. Thus, the residual enzyme in cells other than erythrocytes appears to be sufficient to almost totally prevent accumulation of toxic metabolites.


Temperature perturbation studies of sarcoplasmic reticulum from malignant hyperthermia pig muscle.

The effects of varying temperatures from 25 degrees to 37 degrees C on calcium binding characteristics of sarcoplasmic reticulum from malignant hyperthermia-susceptible (MHS) and control pig muscle were examined. Two groups of MHS pigs were included: those with high susceptibility to malignant hyperthermia (MHS group) and a cross-bred, less susceptible group (MHX). At 25 degrees C, calcium binding was lower for MHS than for controls and MHX. As temperature was increased by 2 degrees C jumps, calcium binding decreased in all sarcoplasmic reticulum fractions. At 35 degrees C a sharp decrease in calcium binding occurred in the MHS and MHX fractions. The sharp decrease in calcium binding at 35 degrees C differentiated the MHS and MHX fractions from controls. The initial velocity (Vi) for calcium binding was lower in MHS fractions between 25 degrees and 35 degrees C when compared with MHX and controls. All fractions had increased Vi values as temperature increased from 25 degrees to 35 degrees C. From 35 degrees to 39 degrees Vi for controls increased markedly. In contrast, Vi for the MHX fraction decreased as temperature exceeded 35 degrees C. These temperature effects on calcium binding characteristics of sarcoplasmic reticulum from MHS and MHX muscle may be indicative of a membrane transition that impairs calcium binding.


Neutrophil-binding immunoglobulin G in systemic lupus erythematosus.

The objectives of these studies were to quantify the amounts of immunoglobulin (Ig)G bound to peripheral blood neutrophils from patients with systemic lupus erythematosus (SLE) and to determine the contributions of soluble immune complexes or anticell antibodies to the levels of IgG neutrophil-binding activity in SLE sera. Neutrophil-bound IgG, determined by a sensitive antiglobulin inhibition assay, was elevated in 7 out of 14 SLE patients compared with values obtained in 23 normal controls. The levels of IgG neutrophil-binding activity in sera were elevated in 22 of 38 patients with SLE over the values seen with 36 normal sera. No correlation was found between the peripheral blood neutrophil counts in the SLE patients and the values for IgG adherent to the cells or serum cell-binding activity. The sera from 18 patients with SLE were fractionated by gel filtration. Elevated levels of IgG neutrophil-binding activity were found in 11 of the 18 G-200 excluded pools and in 13 of the G-200 IgG pools. In nine sera elevated levels were observed in both pools. F(ab')2 fragments of IgG from SLE sera bound to normal polymorphonuclear leukocytes in greater amounts than F(ab')2 fragments of IgG from normal sera. A significant correlation existed between the values of IgG neutrophil-binding activity found in SLE sera and those obtained with both the G-200 excluded and IgG pools. Sucrose density gradient fractionation of four sera from SLE patients confirmed the presence of both large (greater than 19S) and intermediate-sized (7S-19S) cell-binding immune complexes as well as of monomeric IgG antibodies to neutrophils. The levels of IgG neutrophil-binding activity in the SLE sera correlated well with the results obtained with the Raji cell assay for immune complexes as well as with the titer of antibodies to nuclear antigens. These data indicate that circulating neutrophils from patients with SLE commonly have increased amounts of cell-bound IGG. The elevated levels of IgG neutrophil-binding activity in the sera of these patients are caused by both soluble immune complexes and antibodies reactive with neutrophils.


Staphylococci-induced human platelet injury mediated by protein A and immunoglobulin G Fc fragment receptor.

Bloodstream infections with staphylococci are accompanied by thromboembolic complications. We have studied the mechanism of the interaction of staphylococci with human blood platelets. Staphylococci that possess protein A, a bacterial receptor for the Fc fragment of immunoglobulin G (IgG), caused aggregation of human platelets in whole plasma accompanied by release of [(3)H]serotonin. These reactions were time and concentration dependent, requiring two or more staphylococci per platelet to give maximal response within 5 min. The interaction between staphylococci and platelets required the presence of cell wall-bound protein A and of IgG with an intact Fc fragment. It did not require an intact complement system. Cell wall-bound protein A (solid phase) was capable of aggregating human platelets in whole plasma. In contrast, free, solubilized protein A (fluid phase) did not cause measurable aggregation, and release of [(3)H]serotonin was reduced. An excess of free, solubilized protein A blocked aggregation of human platelets induced by staphylococci in whole plasma. The role of the Fc fragment of IgG in the staphylococci-human platelet interaction was demonstrated by an experiment in which free, isolated Fc fragment blocked aggregation of platelets in whole plasma induced by staphylococci. Furthermore, binding of (125)I-protein A to human platelets was demonstrated in the presence of complete IgG with intact Fc fragment but not in the presence of the F(ab)(2) fragment. Binding of the protein A-IgG complex to the human platelet Fc receptor was paralleled by the release of [(3)H]serotonin. These results represent a novel example of the interaction of two phylogenetically different Fc receptors, one on prokaryotic staphylococci and the other on human platelets. Their common ligand, IgG, is amplified by one Fc receptor (protein A) to react with another Fc receptor present on human platelets, which results in membrane-mediated aggregation and release reaction occurring in whole plasma. This mechanism can be of significance in the pathomechanism of thromboembolic complications at the site(s) of intravascular staphylococcal infection.


Renal adaptation to a low phosphate diet in rats.

The major renal adaptive changes in response to selective dietary phosphate restriction are a marked reduction in urinary excretion of phosphate and an increased urinary excretion of calcium; at the cellular level, there is selective increase in renal cortical brush border membrane phosphate uptake and increase in specific activity of alkaline phosphatase. In the present study we examined whether these functional and biochemical adaptive changes could be blocked by drugs known to inhibit protein synthesis. Administration of actinomycin D or cycloheximide to rats switched from a diet with normal phosphate content (0.7%) to a diet with low (0.07%) phosphate content either completely (actinomycin D) or partially (cycloheximide) prevented the expected decrease in urinary excretion of phosphate and increase in the urinary excretion of calcium. The specific activity of alkaline phosphatase measured in crude membrane fraction (washed 100,000 g pellet) from renal cortical homogenate in animals fed a low phosphate diet and treated with actinomycin D or with cycloheximide was significantly lower than in control animals also on a low phosphate diet receiving placebo; but there were no differences between treated and untreated animals in the activities of two other brush border enzymes, gamma-glutamyltransferase and leucine aminopeptidase. Actinomycin D administered to rats maintained on a normal phosphate diet throughout the course of the experiment caused an increase in the urinary excretion of phosphate on the last (6th) day of the experiment but did not change urinary excretion of calcium. In acute clearance experiments, infusion of actinomycin D to rats adapted to a low phosphate diet did not increase fractional excretion of phosphate. In separate experiments, using the same dietary protocol as above, brush border membrane fraction (vesicles) was prepared from renal cortex of rats sacrificed at the end of the experiment. In this preparation Na(+)-dependent (32)Pi and d-[(3)H]glucose uptake and activities of brush border enzymes membrane were determined. Brush border membrane vesicles prepared from rats fed a low phosphate diet showed significantly higher Na(+)-dependent (32)Pi uptake compared with rats fed a normal phosphate diet. This increase in (32)Pi uptake was completely prevented when rats on a low phosphate diet were simultaneously treated with actinomycin D. These differences were specific for (32)Pi transport as no differences were observed in d-[(3)H]glucose uptake among the three groups. There was a positive correlation (r = 0.82, P < 0.01) between (32)Pi uptake and specific activity of alkaline phosphatase measured in aliquots of the same brush border membranes, whereas no such correlation was observed with two other brush border membrane enzymes gamma-glutamyltransferase and leucine aminopeptidase. These observations show that actinomycin D prevents both the functional and cellular renal adaptive changes induced by a low phosphate diet. Taken together, these observations suggest that renal adaptation to a low phosphate diet could be prevented by inhibition of de novo protein synthesis.


The one-point method in predicting dosage regimen in case of hepatic and/or renal failure in presence or absence of change in volume of distribution.

In some clinical situations such as in acute myocardial or coronary infarction, liver disease, renal failure, hypoalbuminemia, displacement from protein binding, etc., both the volume of distribution and the elimination rate may change. The determination of the creatinine clearance may be too time consuming, and the serum creatinine concentration may be an unreliable indicator in some cases (acute renal failure, uremia, muscular diseases, old age, etc). Neither indicates change in elimination by extrarenal routes (metabolism in liver disease). The "repeated one-point method" is presented as clinical tool to calculate the dosage regimen for patients where differences in Vd and kel can be expected. The method is based on the evaluation of one blood sample each in the first two dosing intervals after administration of a test dose. The "repeated one-point method" is compared with the previously published "one-point method."


Cefamandole pharmacokinetics and dosage adjustments in relation to renal function.

The pharmacokinetic characteristics of cefamandole were determined after intravenous administration of a 1-Gm dose to 10 subjects with normal renal function, 10 patients with stabilized renal failure, and five chronic nephritic patients included in a intermittent hemodialysis program. In normal subjects, biological half-life (t1/2) averaged 0.94 hour, the overall elimination rate constant (Ke) was 0.7378 (hr-1), total clearance (Ct) was 223 ml/min/1.73 m2, renal clearance (Cr) was 164 ml/min/1.73 m2, and urine recovery of cefamandole over the 6 hours following a dose amounted to 74 per cent of the administered dose. In patients with stabilized renal failure and in patients on hemodialysis, biological half-life was markedly increased, with a theoretical value of 10.4 hours in case of a creatinine clearance of zero. The amount of antibiotic extracted over a 6-hour dialysis period accounted for 29 per cent of the cefamandole present in the vascular compartment at the beginning of the dialysis procedure. A significant correlation was established between the values of Ke and creatinine clearances, Ccr: Ke = 0.0289 + 0.0063Ccr (r = 0.937). This relationship was used to calculate the loading dose (LD), maintenance doses (D), and dosage intervals (tau) with regard to renal function. From these data recommendations regarding the adjustment of cefamandole dosage to the renal status can be made.


A double-blind study of dezocine in cancer pain.

A double-blind crossover comparison of intramuscularly administration of 10 mg dezocine (Wy 16225), 10 mg morphine, and placebo in ten patients with cancer pain has shown that a dezocine single dose is superior to placebo in producing relief of moderate to severe pain. No side effects were observed.


The clinical analgesic efficacy of oral nefopam hydrochloride.

The analgesic efficacy of 60 and 120 mg nefopam hydrochloride was compared to 650 mg aspirin and placebo in a double-blind single-dose study. Oral doses were administered to 120 patients suffering from acute postsurgical or fracture pain. All active medications demonstrated analgesic activity in comparison to placebo. Patients on 120 mg nefopam obtained the greatest degree of analgesia. Side effects were minor and did not interfere with the course of therapy. The incidence of side effects (sweating, nausea, and lightheadedness) was greater on 120 mg nefopam than on 650 mg aspirin).


Inhibition of suckling in weaning-age rats: a possible serotonergic mechanism.

The nature, development, and specificity of serotonergic involvement in the control of suckling behavior in rat pups from 10 to 35 days of age were studied. During development, suckling normally declines after 10 days and is abandoned after 30 days. It was found that (a) methysergide, a serotonin (5-HT) receptor blocker, reinstated suckling behavior in pups 15 days of age and older but had no effect on the suckling of 10-day old pups, (b) quipazine, a 5-HT receptor agonist, inhibited suckling of pups 10 days of age and older, (c) methysergide pretreatment blocked the quipazine inhibition of suckling, and (d) metergoline, another 5-HT blocker, also stimulated suckling, and fenfluramine, a 5-HT releaser, blocked suckling in deprived pups. Together, these data support the hypothesis that a serotonergic inhibitory mechanism modulates the suckling of weaning-age rats. These pharmacological manipulations of 5-HT appear to alter specific components of suckling behavior involved in its initiation and maintenance but do not appear to alter a general hunger system.


Taste aversions to mother's milk: the age-related role of nursing in acquisition and expression of a learned association.

The development of taste aversion learning to novel cues contained in mother's milk was examined in rat pups. Pups receiving distinctive mild by experimenter-delivered oral infusions followed by toxicosis formed an aversion to the dam's diet. Robust aversions were learned as early as Day 10 and were retained for at least 11 days. When the same distinctive milk was obtained directly from a foster mother through nursing, however, only weanling-age pups (over 20 days) formed an aversion. X-ray analysis of nipple location in the mouths of suckling pups suggested that pups between the ages of 10 and 21 days receive milk at a similar tongue locus. Flavored milk was then delivered at specific time intervals in controlled quantities through tongue cannulas implanted at loci corresponding to the nipple position shown by the X-rays. Cannulated preweanling pups that were attached to a nipple during milk delivery failed to associate the taste cue with illness, whereas both preweanlings off the nipple and weanlings on the nipple acquired aversions to the taste cue in the milk. The evidence obtained in these experiments suggests that pups of all ages are incapable of expressing a taste aversion in a nursing situation and that preweanling pups in particular are also dificient in acquiring aversions within a suckling context. The inability of preweanling pups to acquire taste aversions in a nursing situation appears to result from a failure to associate taste cues with illness rather than a failure to detect taste cues obtained from a nipple.


Approach and withdrawal analysis of the effects of hypothalamic stimulation and lesions in rats.

In a paradigm in which rats would both initiate and terminate hypothalamic stimulation, "purely" rewarding lateral hypothalamic and "purely" aversive medial hypothalamic electrodes were identified. Subjects were then given a series of tests designed to assess the effects of brain stimulation on approach and withdrawal behaviors. Lateral hypothalamic stimulation facilitated approach behavior and suppressed withdrawal behaviors, whereas medial hypothalamic stimulation produced largely the opposite effects. No serious motor deficits due to stimulation were detected with either type of electrode. In a second experiment, the approach-withdrawal effects of bilateral lateral hypothalamic lesions were tested and found to suppress approach behaviors and facilitate withdrawal behaviors. Other neurological examinations revealed motor deficits, but these deficits do not account for the specific pattern of results observed on the approach-withdrawal tests. These approach-withdrawal phenomena are interpreted in terms of altering a natural balance between approach and withdrawl behavior facilitating systems in the lateral and medial hypothalamus, respectively.


Effects of genetic vestibular defects on behavior related to spatial orientation and emotionality.

A large battery of behavioral tests was administered to normal mice and to mice with varying degrees of otoconial agenesis due to genes affecting vestibular development. Many significant differences were found, but a factor analysis revealed that the variance on the 11 best tests could be accounted for in terms of two underlying variables. Factor I, the more important of the two, was associated with activity, habituation, and spontaneous alternation. Factor II appeared to represent a fear of new stimuli or situations. In both cases factor scores were highly related to the degree of otoconial deficiency. One subgroup of mice with severe otoconial agenesis displayed hyperactivity and a total absence of either habituation or spontaneous alternation. In these animals, brain and body development were stunted, and the reactions to amphetamine and physostigmine were opposite to those seen in normal mice. The results support the idea that the static organs contribute importantly to spatial orientation and suggest that early-onset vestibular defects can result in profound alterations of emotionality.


Reduction of ontogenetic retention decrements in rats by pretraining stressful experiences.

Pretraining stressful experiences, either similar to or qualitatively different from the conditioning unconditioned stimulus, reduced ontogenetic retention decrements without directly influencing response acquisition. Rats that received pretreatment with footshock, hypthermia, or restraint on Days 16, 17, and 18 of age showed substantially improved long-term retention of conditioned fear learned at 20 days of age. It was also found that preshock enhanced retention of both an appetitive approach response and punishment of the approach response. Several experiments involving extinction and undertraining manipulations indicated that the facilitation of retention was not directly attributable to acquisition strength.


Evidence for neural inhibition in bittersweet taste mixtures.

Three lines of evidence from psychophysical experiments implied that mutual suppression of bitter and sweet tastes is due to neural inhibition rather than chemical interactions in solution or competition of molecules for common receptor sites. Removal of sweetness from bittersweet mixtures caused the bitterness to increase. This was accomplished by adaptation to sucrose or by treatment with Gymnema sylvestre, neither of which affect the concentration of sucrose on the tongue. Such increases in the bitterness of mixtures, independent of the concentration of the sweet masking substance, are difficult to reconcile with suppression by means of chemical interactions. Similar dependence of suppression on perceived intensity (and independence from concentration) was observed with mixtures of phyenylthiocarbamide and sucrose. Tasters of phenylthiocarbamide showed stronger suppression of sweetness than nontasters. This result was also inconsistent with molecular interactions causing suppression, which would have resulted in the same degree of suppression for the two groups. Instead, these findings support neural explanations of mixture suppression, such as antidromic inhibition or occlusion.


Olfactory stimulation induces filial preferences for huddling in rat pups.

Rat pups of all ages huddle with conspecifics, but the senosory control of contact behavior changes ontogenetically. Thermal cues control huddling until about Day 15, at which time species' odors become the dominant stimulus. The present experiments indicate that the filial response to conspecifics is dependent on olfactory experience. A synthetic chemical scent was added to the smells of the dam from Day 1 to Day 20 postpartum. Standardized videographic tests were used to assess the development of huddling preference. Preferences for nest-typical smells emerged by Day 15 in pups from both scented and nonscented litters. Pups from scented nests preferred to huddle with a scented stimulus rat, whereas control pups preferred a nonadulterated rat stimulus. Additional testing indicated that the affiliative preferences were specific to rearing odor and were not based on decreased aversion to test scents, or on disrupted olfactory discrimination. The ontogeny of species-typical contact behavior is discussed in terms of the induction of a perceptual preference that is based on early odor stimulation.


Thermal homeostasis in pregnant rats during heat stress.

Rats exposed to inescapable heat stress maintained a controlled hyperthermia while increasing heat loss by cutaneous vasodilatation and by grooming behavior. In nonpregnant rats, the evaporation of saliva groomed onto the body surfaces increased exponentially as a function of ambient temperature above 36 degrees C. This was associated with a decrease in the body temperature threshold for salivary secretion from the submaxillary gland, which then began at approximately the same body temperature as cutaneous vasodilatation. In addition, the pregnant rats maintained a lower level of controlled hyperthermia during heat stress than did nonpregnant rats. This appeared to result from a decreased production of metabolic heat, reduced insulation on the ventral surface, and an increased motivation to keep cool during heat stress. These changes met the increased need for thermolysis during pregnancy and provided for thermal homeostasis both in the pregnant rat and in the unborn fetuses.


Human visual evoked responses are related to heart rate.

The purpose of the present experiment was to determine the relation between changes in heart rate and averaged evoked potentials. Sixteen male subjects with variable heart rates received 50 flashes of light during fast heart beats, 50 during slow heart beats, and 50 during midrange heart rate level. Evoked responses were recorded from the scalp overlying the right and left occipital lobes. Heart rate, respiration, eye movements, and cephalic blood flow were also recorded. The results indicated that spontaneous changes in heart rate are related to changes in visual evoked responses and that this relation differs for the two cerebral hemispheres. Furthermore, cephalic pulse amplitude was largest following slow heart beats and smallest following fast heart beats, which suggests that changes in heart rate are related to changes in cerebrovascular as well as electrocortical activity. The results are discussed in terms of formulations derived from behavioral studies regarding the relation between cardiovascular activity and attentional processes.


Neuronal unit activity in the abducens nucleus during classical conditioning of the nictitating membrane response in the rabbit (Oryctolagus cuniculus).

Neuronal unit activity was recorded from the abducens (6th nerve) nucleus, the "final common path," during classical conditioning of the nictitating membrane (NM) response in the rabbit, with the use of a tone conditioned stimulus, an air puff unconditioned stimulus (UCS), 250-msec interstimulus interval, and 60-sec intertrial interval. Animals were given 2 days of conditioning training (104 trials in eight blocks per day) and 1 day of extinction. Control animals were given comparable periods of stimulus presentations, explicitly unpaired. Activity of small clusters of units--"multiple unit" recording--was compared with the amplitude-time course of the NM response. Between-blocks comparisons of neural and behavioral responses indicated an essentially perfect correlation during acquisition of the conditioned response (Day 1, r = .99; Day 2, r = .98) and a slightly lower correlation during extinction (r = .93) for the conditioning animals. Within-blocks comparisons indicated a close correspondence between the histograms of unit activity and the amplitude-time course of the NM response for the conditioning animals in all phase of training and for the control animals in the UCS trial blocks.


Ontogeny of cholinergic mediation of behaviors in the rat.

In a series of six experiments, cholinergic mediation of behavior was studied in immature rats. It was found that although scopolamine disrupted discriminative choice behavior in both 15- and 23-day-old rat pups, it increased latency to choice in 15-day-olds and decreased latency to choice in 23-day-olds. This disruption of discriminated choice behavior was not due to differential shock thresholds or differences in locomotor activity between drug-treated and control animals, nor was it specific to a T-maze shock-escape discrimination task. These results suggest that central cholinergic mediation of different behaviors may mature at different rates.


Mother rats interact differently with male and female offspring.

Lactating Long-Evans rats were observed to interact differently with male and female pups during the first 18 days postpartum. Differences in the mother's behavior were related to the gender composition of her litter (GHL), to the sex of a single introduced pup, and to the sex of individual pups within her litter. Major differences were the greater time spent in licking the anogenital region of own male pups and the greater stimulation of anogenital licking by male foster pups, an effect that did not interact with GHL or age of pup. The GHL interacted with day of testing to affect nest building and time spent near pups.


Comparison of effects of small lesions in posterodorsal septum on spontaneous and rerun correction (contingently reinforced) alternation in rats.

In the first part of the experiment, characteristics of T-maze alternation behavior were compared by giving one group of 11 rats seven sessions under conditions of "rerun correction" (contingent reinforcement for alternation) and another group of 11 rats the same number of sessions with noncontingent reinforcements, i.e., entering either goal arm of the T-maze was reinforced. Both groups alternated significantly above chance, and the difference in medians between groups was small but significant in later sessions. However, rats given rerun correction training quickly came against the "ceiling" of 100% alternation, and individual differences were small. The scores of rats run under conditions of "spontaneous" alternation were more variable, both within and between rats. In the second part of the experiment, six rats in each group received small electrolytic lesions in the posterodorsal septum. There were five operated-control rats from each group. After 2-wk postoperative recovery all rats were again given seven sessions in the T-maze. Under rerun correction procedure (contingent reinforcement), the controls retained near-perfect alternation scores. Most animals with lesions dropped to chance levels but recovered to control level over the seven sessions. Rats tested under spontaneous alternation conditions behaved quite differently. The control group continued to alternate significantly, but rats with lesions significantly alternated less and did not recover.


Active regulation to be lean by rats with ventromedial hypothalamic lesions.

Adult female Long-Evans rats with direct-current electrolytic or radio-frequency thermocoagulatory lesions of the ventromedial hypothalamus (VMH) lived on pellet fragments or a powdered chow containing as much as 1.2% quinine sulfate by weight or lived in Skinner boxes with 45-mg Noyes pellets delivered contingent on fixed ratios (FR) of lever pressing up to FR 128. As had been found previously for intact rats, the body weights maintained by VMH rats were determined by the percentage of quinine sulfate in or the contingency of reinforcement of the food on which they lived. Even when the rats lived on highly adulterated or response-contingent food and were lean, they ate more of that food when the ambient temperature was reduced and less of that food during several weeks of forced feeding of eggnog by gavage. Weight maintenance in the cold and caloric compensation during forced feeding were as precise for VMH rats eating highly adulterated chow or Noyes pellets contingent on high fixed ratios of lever pressing as for VMH rats eating typical laboratory chow ad lib, even though the former rats at the time maintained weights no greater than intact rats and the latter rats at the time were grossly obese. Furthermore, regulation in the cold or during forced feeding was in general only a little less precise for the rats with lesions than for intact rats. It may be as characteristic of VMH rats that they eat to become lean and remain lean as that they eat to be obese. The diets of both intact and VMH rats in some manner determine the adiposities that rats will defend against caloric challenge.


Naloxone and shock-elicited freezing in the rat.

The freezing behavior of the rat that occurs following painful electric shock was found to increase when the animal was pretreated with the opiate antagonist naloxone. Freezing was a positive linear function of drug dose and shock intensity (Experiment 2). Naloxone pretreatment enhanced freezing only when the animal was given two or three shocks but did not affect freezing when the animal was given only one shock or not shocked at all (Experiments 3, 4, and 5). Naloxone must be present during shock, nor just during the observation period, in order to increase freezing (Experiment 6). These results suggest that when an animal is shocked, it releases endogenous analgesics (endorphins) that make a subsequent shock less aversive. Naloxone, by blocking the endorphin system, makes the shock more aversive than it would normally be.


Differential effects of localized lesions of n. accumbens on morphine- and amphetamine-induced locomotor hyperactivity in the C57BL/6J mouse.

Mice of the C57BL/6J strain became hyperactive to increasing doses of morphine sulfate. This response was similar to locomotor hyperactivity induced by amphetamine. Lesions and chemical blockade of posterior n. accumbens abolished amphetamine-induced hyperactivity and reduced but did not abolish the morphine response. These experiments demonstrate that the response to the two drugs is mediated by overlapping but noncongruent neural systems.


Computed tomography and ultrasonography in the evaluation of the retroperitoneum in patients with malignant ascites.

The computed tomographic (CT) body scans of 59 patients and ultrasonograms of 31 patients, all with malignant disease, were reviewed to determine the effect of ascites on the ability to image the retroperitoneum. In 95% of cases evaluated by CT, the retroperitoneal structures were well seen. In 35% of the cases evaluated by ultrasonography, the retroperitoneum was completely obscured by bowel gas and partially obscured in an additional 55%. As a result of this study, it is felt that CT should be the procedure of choice when a thorough evaluation of the retroperitoneum is necessary in patients with large amounts of abdominal ascites.


Contrast computed tomography in the diagnosis of acute cholecystitis.

Computed tomography (CT) has the ability to detect small variations in tissue density. Meglumine diatrizoate was given intravenously to four patients with clinical acute cholecystitis as part of the CT scanning procedure. The enhancement of the thick gallbladder wall, together with an enlarged gallbladder and the presence of stones, confirmed the diagnosis of acute cholecystitis. Our present experience indicates that, after contrast medium administration, CT has a distinct place in the assessment of acute inflammation of the gallbladder.