Reconstitution of the thermostable trimeric phage P22 tailspike protein from denatured chains in vitro

Intermediates in the intracellular chain folding and association pathway of the P22 tailspike endorhamnosidase have been identified previously by physiological and genetic methods. Conditions have now been found for the in vitro refolding of this large (Mr = 215,000) oligomeric protein. Purified Salmonella phage P22 tailspikes, while very stable to urea in neutral solution, were dissociated by moderate concentrations of urea at acidic pH. The tailspike protein was denatured to unfolded polypeptide chains in 6 M urea, pH 3, as disclosed by analytical ultracentrifugation, fluorescence, and circular dichroism. Upon dilution into neutral buffer at 10 degrees C, the polypeptides fold spontaneously and associate to form trimeric tailspikes with high yield. Like native phage P22 tailspikes, the reconstitution product is resistant to denaturation by dodecyl sulfate in the cold and displays endorhamnosidase activity. Sedimentation coefficients, electrophoretic mobility, and fluorescence emission maxima of native and reconstituted tailspikes are identical within experimental error. By characterization of intermediates, localization of temperature-sensitive steps, and analysis of the effect of previously identified folding mutations, the reconstitution system described should allow comparison of in vivo and in vitro folding pathways of this large protein oligomer.

Spontaneous motor activity in healthy volunteers after single doses of haloperidol

Video recordings of the spontaneous motor activity of 6 healthy volunteers after treatment with 0.75 mg haloperidol i.v., or placebo, were transcribed into a time-series protocol of motor behaviour. Characteristic changes seen after the injection of haloperidol consisted in a reduction of the motility of the extremities and prolongation of the phases of both movement and immobility of the head. The tested dose of haloperidol induced a distinct rise in serum prolactin and sedation, but had no effects on the pharmaco-EEG or on the critical flicker-fusion frequency. Analysis of the motor phenomena evoked by neuroleptics in healthy persons and in patients may help, on the other hand, to establish correlations with the motor effects observable in preclinical investigations in animals and might also contribute towards the elucidation of the extrapyramidal side-effects of these drugs.

[Characterization and detection of bulimia in the city of Buenos Aires]

A screening of Bulimia, an eating disorder associated to Obesity and Anorexia Nervosa, has been carried out in the city of Buenos Aires. The data were obtained by means of the questionnaire of Pope & Hudson, administered to young women who attend diet and physical activity programs. Control groups were constituted by female university students and boutique employees. The results indicate that diet and physical fitness searchers are groups at risk of Bulimia. It is concluded that proper preventive measures can be taken by informing and training the personnel, professional or not, in charge of those institutions, and also by promoting the adequate information within the population.

Influence of magnetic resonance imaging on human body core and intravascular temperature

Deep and superficial body temperatures were measured by in vitro and in vivo experiments, using a fluoroptic procedure and a variety of magnetic and electromagnetic fields, in the course of magnetic resonance imaging (0.35 T; 1.5 T). In vitro experiments were performed to select and check the appropriate temperature method. Temperature measurements in the human body were carried out centrally (esophageal and rectal measurements). In vivo experiments in 30 volunteers showed no significant changes (p = 0.05) in central or peripheral temperatures resulting from the application of static or dynamic fields or radiofrequency.

EEG as a neurotoxicological indicator

In living organisms both chemical agents and physical factors [16] may produce neurophysiological change that affects EEG activity. EEG signals are very suitable for non-invasive measurement of CNS reactions, but quite complicated equipment is necessary for measurement and analysis. We have implemented a system that permits the study of EEG changes both in time and frequency domains using broad-band analysis or fast Fourier transformation (FFT). Experimental animals were influenced by high doses of toxic agents (CO, CS2, barbiturates, pesticides), drugs and both non-ionizing and ionizing radiation. The EEG changes reflecting the influencing factor, respectively its quantity may be divided into several classes: (1) appearance of new activities; (2) disappearance of some activities; (3) increase of amplitudes, respectively spectral power densities (SPD) in certain frequencies; and (4) decrease of amplitudes, respectively SPD in certain frequencies. All changes are related to the controls, i.e. to the relatively normal state of CNS. Furthermore it is possible to investigate the temporal dynamics of these changes. Physiological concordance of these findings is sometimes possible from clinical analogues, but in other cases is unknown and considerable effort will be necessary to elucidate these correlates. Anyhow in some toxic substances, the EEG may be quite insensitive as an indicator of neurotoxicity. The best way to solve these problems is to collect sufficient experimental data for complex analysis. Although few relevant data are currently available, temporal and frequency domain measures of EEG activity appear to have promise as neurotoxicity indicators.

[Effect of in vivo nuclear magnetic resonance tomography on somatosensory and visual evoked potentials in the human]

By means of registration of somatosensory (SSEP) and visual (VEP) evoked potentials under the influence of different magnetic and electromagnetic fields of Magnetic Resonance we investigated the influence of Magnetic Resonance Imaging (MRI) on human nervous system (all measurements with an 1.0 T MR imager are performed outside and inside the static magnetic field, before and after MR imaging). In vivo experiments on 20 healthy volunteers show in SSEP registrations as well as in VEP-registrations no measurable influence on nerve conduction. The measured latencies before and after MR imaging are found inside the standard values which are valid for healthy volunteers. In vivo experiments at field-strengthens up to 1.0 Tesla show no significant changes of the central and peripheral conduction velocity with human beings.

The two- and three-dimensional structure of the microcirculation of the chick chorioallantoic membrane

The chick chorioallantoic membrane (CAM) is a common model for studying biological processes, but descriptions of the CAM circulatory system and especially experimental preparations of the CAM in shell-less eggs are both scant and controversial. We studied the CAM structure and the three-dimensional spatial configuration of the CAM vessels using five methods: in vivo stereoscopic observations, whole-mount preparations, histological sections, corrosion cast microinjection techniques, and the reconstruction of a three-dimensional wax model. Our findings show that the CAM consists of a superficial two-dimensional layer composed of a network of a very dense capillary mesh, floating over and enclosing a deeper three-dimensional space in which medium and larger free-floating vessels are seen to supply and drain the superficial layer. It is interesting to note that no tips or sprouts of blood vessels were observed during the development of the CAM vessels. In a shell-less egg preparation, the capillaries were found in the mesoderm layer of the CAM and not in or superficial to the ectoderm as is the case in the CAM of the intact egg which adheres to the shell membrane.

Beta 2-microglobulin amyloidosis (AB2M) in patients undergoing long-term hemodialysis. A new type of amyloid

Amyloidosis has been increasingly recognized in association with renal failure and chronic hemodialysis. This report describes three patients who had long-term hemodialysis (between 7-18 years), in whom deposits developed of a new type of amyloid of beta 2-microglobulin origin. Beta 2-microglobulin amyloid (AB2M) was found in multiple organs, i.e., bone, subendocardium, gastrointestinal blood vessels, tongue, and carpal tunnel connective tissue. AB2M displayed characteristic amyloid features on conventional light and polarized microscopic examination after congo red staining. However immunostaining with anti-amyloid A protein, kappa, and lambda antisera were negative. The studied material reacted positively with beta 2-microglobulin antisera, identifying AB2M in all three cases. Ultrastructural study revealed an unusual curvi-linear fibrillar configuration. AB2M appears to be a new subtype of systemic amyloidosis secondary to renal failure and long-term hemodialysis.

Biological assessment of exposure to antimony and lead in the glass-producing industry

The oxide of trivalent antimony is used in the glass-producing industry as a refining agent and as a glass colouring. The batch contains up to 2% Sb2O3, a substance which has shown carcinogenic properties in animal experiments. The internal levels of antimony and lead in blood (SbB and PbB) as well as the excretion with the urine (SbU and PbU) were determined by hydrid and electrothermal atomic absorption (HY-AAS and ET-AAS), respectively. In addition, measurements of airborne Sb2O3-concentrations were performed. The 109 volunteers were employed in four different fields: melting area, batch bunker, glass-washing area, and transport/maintenance. Differences between the concentrations of antimony and lead in blood and urine with respect to the fields of activity were evaluated statistically. The highest values of airborne Sb2O3, with up to 840 micrograms/m3 (TWA), were detected in the batch bunker. Correspondingly, significantly enhanced SbU-values from 1.5 to 15.7 micrograms/l (median: 5.0 micrograms/l) were found in specimens collected from the batch mixers. In the same group, the lead excretion (PbU) with values from 9 to 110 micrograms/l (median: 43 micrograms/l) was also found to be the highest. Due to the fast renal excretion of antimony, the determination of SbU is useful for biological monitoring.

The anti-proliferative effect of lithium chloride on melanoma cells and its reversion by myo-inositol

The effect of LiCl on melanoma cell growth and differentiation was studied in mouse and human melanoma cell lines. LiCl markedly inhibited B16 and HT-144 melanoma cell growth in vitro. Clonogenicity in soft agar of the melanoma cells was also markedly inhibited by LiCl. Pretreatment of B16 mouse melanoma cells with LiCl delayed the appearance of melanoma tumours in syngeneic mice. Growth inhibition of cells was accompanied by morphological and biochemical alterations. LiCl induced cell enlargement and formation of dendrite-like structures. The activity of NADPH cytochrome c reductase, an enzymatic marker of endoplasmic reticulum was significantly (2-3 fold) increased. Addition of myo-inositol to cell cultures partially reversed the anti-proliferative and morphological effects of LiCl on melanoma cells. This finding may suggest that the anti-proliferative effect of LiCl is related to its effect on phosphatidylinositol metabolism.

Chemical inducers of differentiation, dimethylsulfoxide, butyric acid, and dimethylthiourea, induce selective ultrastructural patterns in B16 melanoma cells

The morphology and ultrastructure of B16 melanoma cells was examined after treatment of the cells with the chemical inducers of differentiation dimethylsulfoxide (DMSO), butyric acid, and dimethylthiourea (DMTU). The treated B16 melanoma cells seemed to be enlarged and more flattened, and to possess dendrite-like structures as revealed by scanning electron microscopy. The main ultrastructural features, depicted by transmission electron microscopy in DMSO-treated B16 cells were: a marked increase in melanin granules, migration of the melanin granules to the dendrites, and appearance of melanosome aggregates. Butyric acid did not induce melanin biosynthesis; however, it stimulated rough endoplasmic reticulum (RER) formation all over the cytoplasm. The DMTU-treated cells also showed a well developed RER accompanied by early stages of melanosomes and melanin granules. The increase in the endoplasmic reticulum was also reflected by enhancement of NADPH cytochrome c reductase activity, an enzymatic marker of the endoplasmic reticulum. The mitochondria in the DMTU-treated cells were swollen with disrupted cristae. The results indicate that DMSO, butyric acid, and DMTU induce different ultrastructural patterns in B16 melanoma cells. These findings correlate with the biochemical alterations induced in melanoma cells by these agents.

Pharmacodynamic profile of the selective beta 1-adrenoceptor antagonist bisoprolol

The pharmacodynamic activity of (+/-)-1-[4-(2-isopropoxyethoxymethyl)-phenoxy]-3-isopropylamino-2- propranol- hemifumarate (bisoprolol, EMD 33 512) has been investigated under in vitro and in vivo conditions. Bisoprolol was found to be an effective beta-adrenoceptor antagonist, the pA2 values determined against isoprenaline in guinea pig atria and tracheal muscle being 7.45 and 6.41, respectively. Thus, the selectivity ratio of bisoprolol in favour of beta 1-adrenoceptors is 11. Inhibition of the isoprenaline-induced tachycardia in guinea pigs indicated a long duration of action for bisoprolol. The compound was devoid of intrinsic sympathomimetic activity as shown by the lack of effect on heart rate in anaesthetized and reserpine pretreated rats. Studies in rabbits and guinea pigs revealed a local anaesthetic activity of bisoprolol at high concentrations. Bisoprolol protected the hearts of anaesthetized dogs against the sequelae of intermittent coronary occlusions, as judged by the reduction of the ST-segment elevation in the epicardial ECG. Bisoprolol exerted a blood pressure lowering effect in conscious renal hypertensive dogs after oral administration of 30 micrograms/kg. There was no indication of any action on the CNS in monkeys following an oral dose of up to 8 mg/kg.

Avoidance acquisition in adult and senescent rats

Male rats aged 6, 19, or 33 months were trained successively in one- and two-way avoidance tasks. The one-way avoidance test consisted of up to 30 trials given in a single session with the conditional stimulus (CS; 14-kHz tone) presented for either 3 s or for 10 s in separate groups. Senescent rats performed poorest, middle-aged rats intermediately, and young adult rats best. Failure of the longer CS to yield better acquisition than the short CS in the senescent group suggested that the age-related deficit probably did not result from slower responding. In subsequent shuttle box training there was no appreciable age difference in achieving the learning criterion. A compound visual-auditory CS was used, and in further evaluation of well-trained rats it was found that the auditory component was much more effective than the visual component in eliciting avoidance. However, this differential effect of the two stimuli was much weaker in the senescent group than in the young adult group. Nonetheless, these same senescent and adult rats readily learned to make avoidance responses using only the auditory CS, demonstrating that this was an effective stimulus for all age groups.

Altered light/dark activity difference with aging in two rat strains

The daily activity rhythm of adult and senescent male rats of two different strains (Iva:SDIV and Emd:Wi-AF/Han) was evaluated over several days with a capacitance-induction motility monitor. The Iva:SDIV rats were 6 to 9 or 29 to 32 months old and the Emd:Wi-AF/Han rats were 3 to 5, 16 to 18, or 31 to 39 months old at the time of testing. The rats were maintained in individual cages under a 12:12 hr light/dark regimen prior to and during this experiment. Senescent rats were much less active during the dark phase and somewhat more active during the light phase than same-strain young adult rats. This pattern of results was found for measurement of gross and fine movements combined (high sensitivity setting) and to a lesser extent for gross movements alone (low sensitivity setting). Furthermore, in the senescent rats the absolute magnitude of the light/dark activity difference was found to be positively related to the subsequent survival time.

Long-term treatment of tumor-operated mice with high doses of alpha-difluoromethylornithine

Mice inoculated subcutaneously with a mammary adenocarcinoma M3cell suspension and submitted 10 to 15 days later to the surgical removal of primary tumors have been chosen in our laboratory as the experimental model to study the effect of several drugs on metastasis spreading. A 90-day treatment of tumor-operated mice with high doses of alpha-difluoromethylornithine showed, in addition to a marked decrease of lung metastases, several side effects including a loss of body weight, a delay of surgical wound healing and a reduced number of megakaryocytes in bone marrow. The measurement of ceruloplasmin in serum has indicated that treated animals contained increased levels of this oxidase activity in spite of the polyamine depletion caused by alpha-difluoromethylornithine. These results rule out a direct correlation between ceruloplasmin activity and polyamine concentration.

Drug induced hypothermia in adult and senescent rats

Temperature regulation was evaluated in senescent (34-40 month old) and adult (8-9 month old) female Iva:WIWU and Emd:Wi-AF/Han rats. Injection of 1.5 mg/kg BW apomorphine HCl or 1.0 mg/kg BW oxotremorine sesquifumarate produced comparable maximal hypothermic responses in adult and senescent rats. However, the latency to reach maximal hypothermia after oxotremorine (but not apomorphine) was longer in senescent than in adult rats of both strains.

Drinking by senescent and adult rats in response to regulatory challenges

The regulation of water and electrolyte balance was elevated in senescent (greater than 31 months) and adult (5-10 months) rats of several strains. Weekly food and water intake, drinking induced by 24-hr water deprivation and drinking induced by injection of hypertonic saline were roughly the same in old and adult rats. However, senescent rats drank less after injection of the beta-adrenergic agonist isoprenaline than adult rats. There were no appreciable strain differences in drinking in response to these regulatory challenges although baselines sometimes differed between strains.

Location of the angiogenic activity in the pregnant human uterus

Angiogenic activity was known to be intensely dynamic during pregnancy with a geometric orientation towards the site of implantation. Therefore this study was designed to test whether the uterine lining of pregnancy, the decidua, induces angiogenic activity on the chorioallantoic membrane (CAM). Twenty-three decidual specimens obtained during legally induced abortions were implanted into the 9-day-old chick CAM. All decidual specimens showed strong angiogenic activity as measured by 9-fold increase in radial blood vessels, with a geometrical formation of 'spokewheel' pattern extending over a range of 1.2 cm within 48 h.

High-performance size exclusion chromatography as a rapid method for the separation of steroid hormone receptors

High-performance size exclusion chromatography ( HPSEC ) on TSK 3000SW molecular sieve columns was used to separate estrogen, progestin, and androgen receptors from several target tissues within 50 min on the basis of size and shape (Stokes radius). Moreover, this system provided for the detection of heterogeneity of receptor species (isoforms) in a manner superior to that observed with sucrose density gradient centrifugation. HPSEC separated various estrogen receptor isoforms having Stokes radii of greater than 61 A, approximately 48 A and 29-32 A. Agents such as potassium chloride and sodium molybdate which alter the distribution of estrogen receptor species on sucrose density gradient centrifugation, promote similar alterations in receptor profiles when HPSEC was employed. Our investigations suggest the use of [125I]iodoestradiol-17 beta and HPSEC allows the sequential analysis of estrogen receptor species providing new insights into receptor composition and structure. It is concluded that HPSEC has a broad application in the field of steroid hormone receptors. This method should be useful in studies ranging from measurements of molecular and kinetic properties to their mode of cellular interaction and regulation.

[Contact urticaria caused by skin test in pyrazolone allergy]

About one third of patients with anaphylactic reactions to pyrazolones showed contact urticaria induced by to at least one pyrazolone after 30-60 min in patch test. This reaction was never observed in patients with various exanthemas or allergic contact dermatitis to these medicaments. Contact urticaria in patch test was mostly caused by propyphenazone, aminophenazone, and metamizole. The suspicious pyrazolone provoked positive results in only about 70%. No correlation could be found between contact urticaria in patch test and severity of allergic history, short interval before skin test and atopic constitution.

The dynamics of the stress stage of osmotic haemolysis

A simple physical model for the dynamics of the stress stage of osmotic haemolysis is presented. An 'elastic restitutive coefficient' for the red cell membrane is defined to relate the increase of internal pressure to the volume change during the stress stage, and it is estimated on the basis of the work of Evans et al. (1976, 1977). It is shown that the time elapsed between complete swelling and the start of haemoglobin leakage can be a substantial part of the total haemolysis time, in accordance with experimental results reported in the literature.

[Estrogen and progesterone receptors in corpus uteri carcinoma and their clinical significance]

In 49 carcinomas of the endometrium of varying clinical stages the estrogen and progesterone receptors were studied by charcoal absorption methods. The cases were studied between 1979 and 1981. 64% of the investigated cases were receptor positive, 35% were receptor negative. Estrogen receptors were detected in 61% and progesterone receptors in 49% of the cases. Both estrogen and progesterone receptors were detected in 45% of the cases. The receptor status was correlated with the clinical stage, the microscopic differentiation and the age of the patient. In 30 cases with a follow-up of more than 3 months it was attempted to determine the prognostic value of the steroid receptor status in endometrial carcinoma. The treatment possibilities with progestational agents and antiestrogens and with tamoxifen were discussed in view of the receptor status.

The importance of gestagen, tamoxifen and steroid receptors in the therapy of endometrial cancer. Report of an experiment

Six human endometrial cancers in different clinical stages were xenotransplanted into thymusaplastic nude mice. Estrogen and progesterone receptors in the tumor tissue were determined in each case. Two carcinomas with both estrogen and progesterone receptors showed a better clinical course and grew more slowly in nude mice than the four carcinomas with no receptors at all. Treatment with the antiestrogen Tamoxifen in the carcinoma with positive estrogen receptors showed a significant growth retardation compared with the control group. Estrogen treatment gave accelerated growth, whereas gestagen treatment showed no significant effect. The progesterone receptor content of the receptor-positive tumor tissue might have been too small. None of the four receptor-negative carcinomas showed any influence of tumor growth during endocrine therapy. The results demonstrate the importance of receptor determination as a prognostic sign and, further, allow the endocrine therapy of endometrial carcinomas to be complemented with Tamoxifen in estrogen-receptor-positive tumor tissue.

Bacterial breakdown of benomyl. I. Pure cultures

With different soil and water samples as inoculum and the benzimidazole fungicides benomyl (either as Benlate or as the pure compound) and thiabendazole as selective agents, a large number of, mainly fluorescent, Pseudomonas strains were isolated which nearly all were able to grow in a mineral medium with benomyl as the sole source of carbon. However, no growth occurred with any of a series of other benzimidazole compounds, viz. benzimidazole, 2-aminobenzimidazole (2-AB), thiabendazole and fuberidazole. Although benomyl--or rather its non-enzymatic breakdown product methyl benzimidazol-2-yl carbamate (MBC)--was partially degraded to 2-AB, most probably n-butylamine, which arises after splitting off of the butylcarbamoyl side chain, was the actual carbon source for the Pseudomonas isolates. When incorporated in a lactate medium, 2-AB markedly inhibited the growth of Pseudomonas spp. at a concentration of 250 microgram/ml, with complete inhibition being attained at 500 microgram/ml. For Bacillus spp. grown in liquid peptone media benzimidazole compounds were inhibitory at concentrations of 500-1000 microgram/ml, with a toxicity increasing in the order: benzimidazole less than thiabendazole less than MBC less than 2-AB.

Bacterial breakdown of benomyl. II. Mixed cultures

Experiments with mixed bacterial cultures grown in liquid media which contained the benzimidazole fungicide benomyl, with or without Na-lactate, as source of carbon provided circumstantial evidence for cleavage of the benzimidazole heterocyclic ring. Yet, neither 2-aminobenzimidazole (2-AB) nor benzimidazole, as sole source of carbon, supported any bacterial growth. "Total 14C-balance analysis" experiments conclusively showed production of 14CO2 from [2-14C]methyl benzimidazol-2-yl carbamate (MBC), and thus cleavage of the benzimidazole nucleus: bioassays, however, showed that the actual rate of benomyl and MBC breakdown was only small, the parent compound benomyl being still recovered in substantial quantities after up to 80 days of incubation. Therefore, cleavage of the benzimidazole ring is probably a matter of cometabolism, n-butylamine which originates from the butylcarbamoyl side chain serving as the proper source of carbon. Besides radiolabelled 2-AB and CO2, an unknown metabolite was isolated which showed characteristics of a 2-AB-nucleotide. Probably, 2-AB was incorporated into bacterial DNA, which upon lysis of the bacterial cells gave rise to the nucleotide in question. Therefore, 2-AB might exert its inhibitory action by interfering with the normal functioning of DNA.

METABOLISM OF AROMATIC COMPOUNDS IN HEALTHY AND RUST-INFECTED PRIMARY LEAVES OF WHEAT: II. STUDIES WITH L-PHENYLALANINE-U-14C, L-TYROSINE-U-14C, AND FERULATE-U-14C

Wheat leaves infected with stem rust, especially those of susceptible plants, contained more phenylalanine and tyrosine than healthy leaves. The utilization of phenylalanine was increased in both the susceptible and resistant reaction, but the utilization of tyrosine was increased only in the susceptible reaction. No evidence of interconversion of these amino acids was obtained.In n-butanol extracts, which contained glycosides, many constituents were labelled after feeding of L-phenylalanine-U-14C. Most of the n-butanol extractives from resistant-reacting leaves contained more label than those from susceptible-reacting leaves or from healthy leaves. However, one of the n-butanol extractives from susceptible-reacting leaves was 5–10 times as active as that isolated from the other tissues.With L-phenylalanine-U-14C and ferulate-U-14C as precursors, more activity was recovered in insoluble than in soluble esters (of ferulate and p-coumarate). With L-tyrosine-U-14C as precursor, the reverse was observed. After infection, the proportion of label in insoluble esters increased more in resistant leaves than it did in susceptible leaves, regardless of the precursor used.A major portion of the activity from these precursors was recovered in the insoluble residue that contained protein and other polymers. In the experiment with L-phenylalanine-U-14C, this residue was fractionated into protein and non-hydrolyzable material. Susceptible-reacting leaves contained equal amounts of activity in these fractions, while resistant-reacting leaves incorporated 2.5 times as much activity into the non-hydrolyzable material as into protein.