The maintenance of colchicine-arrested metaphases in plants requires protein synthesis

With the aim of finding out factors involved in chromosomal condensation, the kinetics of both metaphase accumulation and the subsequent formation of restitution nuclei in the presence of 1 mM colchicine have been analyzed in Allium cepa L. meristems. Restitution nuclei are formed by decondensation of the chromosomes from the c-mitoses and the reformation of nuclear envelopes around them. The study has been carried out in control conditions as well as in conditions which either inhibit protein synthesis (1 microgram/ml cycloheximide) or modify the accuracy of transcription (by near ultraviolet light irradiation under anoxia of cells with bromosubstituted-DNA). The results suggest that the high condensation of chromosomes observed in colchicine-arrested metaphases depends on sustained synthesis of protein, and that the DNA regions coding for such proteins are transcribed not before late prophase. By using cells, the genome of which has been partially bromosubstituted, fed bromodeoxyuridine during different fractions of this S period, it could be inferred that the coding regions for the proteins involved in chromosome condensation are probably multiple since they replicate throughout the whole S period.

Differential expression of the ICF (immunodeficiency, centromeric heterochromatin, facial anomalies) mutation in lymphocytes and fibroblasts

Fibroblasts from a patient with ICF syndrome were grown in the presence of excess of nucleotides, in media with different amounts of folic acid, and with caffeine in an attempt to induce the chromosomal anomalies observed in lymphocytes. We induced despiralisation and breakages in the centromeric heterochromatin of chromosomes 1 and 16 but not associations and multibranching. We suggest that the absence of the major chromosomal anomalies in fibroblasts from patients with ICF might be the result of both a longer G2 in these cells and differential patterns of interphase heterochromatin associations in the two tissues.

Base stacking of simple mRNA cap analogues. Association of 7,9-dimethylguanine, 7-methylguanosine and 7-methylguanosine 5'-monophosphate with indole and purine derivatives in aqueous solution

Equilibrium constants for the association of different ionic forms of 7,9-dimethylguanine, 7-methylguanosine and 7-methylguanosine 5'-monophosphate with indole, caffeine and various methylated adenines have been determined by distributing the latter compounds between an organic solvent and aqueous solutions of the 7-methylguanine derivatives. The data are compared to those obtained for the association of unsubstituted purine with the same cosolutes. The stacking affinity of both cationic and zwitterionic forms of the 7-methylguanine ring correlates with the ring polarizability rather than the polarizing power of the cosolute. The cationic species stacks usually more efficiently. The chemical nature of the N9-substituent has only a moderate influence on the base-stacking properties.

Preserved cytosolic and synthetic liver function in jaundice of severe extrahepatic infection

We investigated prospectively 9 adult patients with the syndrome of jaundice complicating severe extrahepatic infection both clinically and by quantitative liver function tests. Five patients having severe extrahepatic infection without jaundice were used for comparison. Intraperitoneal infection was found to be a major risk factor for development of jaundice. Jaundice was mainly associated with gram-negative infection, but did not influence survival. Duration of jaundice was dependent on control of the underlying infection. Liver function tests showed a severely deranged organic anion transport, whereas synthetic, cytosolic, and microsomal functions remained preserved. Our study shows that (a) the syndrome of jaundice associated with extrahepatic infection is a functional disorder that is reversible upon control of infection, and that (b) cytosolic, synthetic, and microsomal function is preserved. This may have consequences for both assessing prognosis and clinical management.

Measurement of food perception, food preference, and nutrient selection

Perception, preference, and selection are all objectively measurable performances that discriminate between different levels of entities such as the sugar, thickener, or protein in a food. A rating or an intake may not be controlled by the word that the experimenter or the subject uses to describe it: "protein"-oriented food selection, "thickness" preference, or "sweetness" perception is proved only when the named objective influence, isolated from any other influence, accounts for the observed variations in choice response. Difference-measuring designs can be extended from merely two levels of an influence to a continuum over the natural range of levels, thus evoking linear psychophysical (dose-response) performance from which the strength of that influence can be estimated. Usually, at least a few influences are operative at once on a choice. Because the interactions may vary among people, the only valid causal analysis is at the individual level. Examples are given of food taste tolerance in the elderly, integration of sensory and attitudinal influences, and dietary choices misattributed to carbohydrate craving.

[Central core disease associated with malignant hyperthermia sensitivity]

The authors report the case of a 57-year old woman who was susceptible to malignant hyperthermia (MH) and also had central core disease (CCD) of muscle. The latter was asymptomatic and was discovered when muscle biopsy was performed for in vitro tests of susceptibility to malignant hyperthermia. This case was compared with the 117 cases of CCD and 33 cases of CCD associated with MH published in the literature. Anaesthesia-induced MH is lethal in 80 per cent of the cases without treatment and in 20 per cent with treatment. CCD and MH are both transmitted as autosomal dominant traits. Susceptibility to MH is a functional abnormality of unknown mechanism. CCD is a disease of muscle fibre structure. One may hope that molecular studies and genetic probes will show whether or not these two diseases are transmitted by genes that are similar but distinct and independent.

[Malignant hyperthermia; two cases of MH in the presence of general anesthesia and performing caffeine contracture test]

In the present report we described two cases of malignant hyperthermia under halothane anesthesia. Case 1; A 54-year-old, 58 kg-male was scheduled for the operation of giant arterio-venous malformation. Anesthesia was induced with thiamylal, fentanyl and pancuronium, and maintained with oxygen, nitrous oxide and halothane. The patient was subjected to halothane inhalation for 26 hours prior to the development of the malignant hyperthermia. Although body temperature rose to 41 degrees C, it returned to normal with the administration of 280 mg of dantrolene and systemic cooling. Case 2; A 31-year-old, 68 kg-female was scheduled for tonsillectomy. Anesthesia was induced with thiamylal, oxygen, nitrous oxide and halothane. After the administration of 70 mg of SCC, marked muscular rigidity occurred and endotracheal intubation was impossible. The operation was postponed. Two months after the first anesthesia, operation was successfully performed under NLA with droperidol and fentanyl. Caffeine contracture test was performed in each case by skinned fiber method and the result showed that the sensitivity to caffeine increased in the isolated skeletal muscle fiber bundles from these patients. Thresholds of caffeine contracture of these skinned fiber bundles were all lower than 5mM caffeine.

X-ray- and mitomycin C (MMC)-induced chromosome aberrations in spermiogenic germ cells and the repair capacity of mouse eggs for the X-ray and MMC damage

Chromosome aberrations induced at the first-cleavage metaphase of eggs fertilized with sperm recovered from spermiogenic cells which had been X-irradiated and treated with mitomycin C (MMC) at various stages were observed using in vitro fertilization and embryo culture technique. Furthermore, the repair capacity of the fertilized eggs for X-ray- and MMC-induced DNA damage which was induced in the spermiogenic cells and retained in the sperm until fertilization was investigated by analysis of the potentiation effects of 2 repair inhibitors, 3-aminobenzamide (3AB) and caffeine on the yield of chromosome aberrations. The frequency of chromosome aberrations observed in the eggs fertilized with sperm recovered from the early spermatid to late spermatocyte stage with X-irradiation of 4 Gy (16-20 days after X-irradiation) was markedly higher than that in the eggs fertilized with sperm recovered from spermatozoa to late spermatid stage (0-8 days after X-irradiation). The induced chromosome aberrations predominantly consisted of chromosome-type aberrations, the main type being chromosome fragment followed by chromosome exchange through all the spermiogenic stages. On the other hand, a high frequency of chromosome aberrations was not induced through all the stages with MMC treatment of 5 mg/kg. The remarkable potentiation effects of 3AB and caffeine were found in the eggs fertilized with sperm recovered from almost all the spermiogenic stages after X-irradiation. In the MMC treatment, a remarkable caffeine effect was observed occasionally in mid-early spermatids to late spermatocytes where a large amount of MMC damage could be induced. These results suggest that the large amount of DNA lesions induced in spermiogenic cells by X-rays and MMC persist as reparable damage until sperm maturation and are effectively repaired in the cytoplasm of the fertilized eggs.

The Zurich study. VIII. Insomnia: association with depression, anxiety, somatic syndromes, and course of insomnia

The association of three subtypes of insomnia with psychic and functional syndromes, and the course of insomnia over 7 years were examined in a Swiss cohort of young adults interviewed three times. Specific associations were found between repeated brief insomnia (RBI) and recurrent brief depression (RBD). Continued insomnia (CI) was associated with major depression. All three subtypes of insomnia were associated with anxiety disorders; 52% of insomniacs were free of concurrent anxiety and depression. Insomnia--especially RBI and CI--was also associated with a number of functional complaints, but not with the consumption of alcohol, medicine, or illegal drugs. Insomniacs with RBI and occasional insomnia (OI) experienced more life events and interpersonal conflicts than controls. These findings support the subdivision of insomnia into different subtypes. The longitudinal analysis showed that insomnia tends to reoccur. For subjects with insomnia either at age 21 or 23 years, there was a higher risk of further insomnia at follow-ups. The specific subtype of insomnia at the first occurrence was not predictive for the outcome: all subtypes of insomnia enhance the risk of relapses in a similar way. Insomnia at age 21 is no precursor of the first onset of a depressive or anxiety disorder within a 2-year follow-up. With respect to the course of insomnia over 7 years, the subtypes did not differentiate.

Perceived and received support: effects on health behavior during pregnancy

The effects of several measures of social support on three health behavior practices during pregnancy--abstinence from alcohol, cigarettes, and caffeine--were explored. Both specificity of support and the distinction between perceived and received support were examined. The sample consisted of 529 pregnant women who completed written questionnaires and telephone interviews. Analyses showed that specific perceived and received support were significant and largely independent predictors of all three behaviors. General social support, however, was not a significant predictor of any of the behaviors. Although others have found perceived support rather than received support to be the critical component of social support in its stress-buffering effects on health, this study offers evidence that received support is also important for facilitating positive health behaviors.

[Screening tests for malignant hyperthermia susceptibility]

The ideal screening test for malignant hyperthermia susceptibility (MHS) has yet to be discovered. It should be simple noninvasive, yet totally specific and sensitive. Until such an ideal test becomes available, allowing simple routine preoperative screening, tests should only be used in certain specific situations. These include: patients in whom a clinical crisis was suspected; the members of the family of a subject labeled MHS because of a fatal, or otherwise, crisis, or in whom tests were positive; patients with other pathological conditions which could be linked to malignant hyperthermia (MH) (some myopathies, effort or stress MH, neuroleptic malignant syndrome). The various tests proposed in the literature aim at revealing MHN subjects, using or not a triggering agent, halothane most often. However, detecting these abnormalities sometimes gives greater insight into the physiopathology of MH than in the detection of an individual patient's susceptibility. The tests have been classified as in vivo, electrophysiological, blood, and in vitro muscle biochemical, morphological, and pharmacological tests. The discovery of new tests gives renewed hope: CPK levels, platelet tests, calcium sarcoplasmic reticular reuptake, lymphocyte Quin 2 test, nuclear magnetic resonance spectroscopy. However, experts worldwide agree that the only reference test to this day remains the in vitro halothane caffeine contracture tests. These tests have shown their reliability; they must be performed on muscle strips obtained from surgically removed muscle biopsies, by laboratories used to this technique and who have at their disposal a sufficiently large group of MHS subjects with a clear-cut clinical crisis, as well as controls. The patients must therefore travel to these laboratories. The design of common protocols for European laboratories on one hand, and the North American laboratories on the other, is a good guarantee of the reliability of these tests.

Alcohol use and its relationship to other addictive and preventive behaviors

Immoderate consumption of alcohol was found to be related to three other potentially addictive behaviors (illicit drug use, smoking, and caffeine consumption) in a randomly drawn sample (n = 1253) of American adults. In addition, alcohol consumption was found to be related to nutritional, life style, safety, and health monitoring preventive behaviors. Although the underlying mechanism for these behaviors is not clear, possibilities include the subsumption of both addictive and other preventive behaviors under a more generalized risk taking (or risk avoidance) dimension.

Pharmacologic provocation and dexamethasone suppression test sensitivity

In expectation of improving sensitivity, the standard 1-mg dexamethasone suppression test (DST) was given to 10 depressed inpatients and repeated with theophylline or caffeine and again following 3 days of lorazepam with abrupt discontinuation. Two patients showed nonsuppression on the standard DST; 2 suppressors changed to nonsuppression after lorazepam discontinuation, and 1 also changed after theophylline. This increase from 20 to 40% sensitivity remains significantly less than a desirable minimum 80% sensitivity (p less than 0.001), which suggests that a consistent DST sensitivity of 80% in melancholia is unlikely to be attained.

Monomerizing effect of caffeine, o-phenanthroline, and tannin on cationic dyes: a model system to analyze spectral characteristics of the intercalative binding to nucleic acids

If used as co-solutes in concentrated solutions of cationic planar dyes, caffeine, o-phenanthroline, and tannin induce striking hyperchromic and bathochromic shifts in their absorption spectra. Likewise, the fluorescence of acridine orange at high concentration greatly increases in the presence of caffeine, the emission peak appearing at a shorter wave-length. These spectral changes, which are similar to those produced by organic solvents, detergents, and alpha-cyclodextrin, reflect the disaggregating (monomerizing) capacity of the co-solutes on stacked chromophores. After washing with saturated solutions of caffeine or o-phenanthroline, the chromatin fluorescence by intercalating fluorochromes is reduced or abolished, which suggests competition effects for intercalative binding modes. These results support the use of caffeine, o-phenanthroline, and tannin in spectroscopic and histochemical studies of dye-stuff interactions with DNA and chromatin.

One-step protocol for assays of total and direct bilirubin with stable combined reagents

We describe an improved colorimetric method for assays of total and direct bilirubin in serum. Bilirubin reacts with diazotized sulfanilic acid in an acidic medium to form a blue azopigment. Total bilirubin is assayed in the presence of reaction accelerators (caffeine, urea, and citric acid), direct bilirubin in their absence. The azo compound so formed is read at the same wavelength (570 nm) in both assays. A sample blank is run in parallel. Standard curves are linear for total and direct bilirubin concentrations up to 513.0 and 256.5 mumol/L, respectively. The method is characterized by (a) use of the same protocol for both assays, i.e., a one-step procedure with short reaction time (5 min at room temperature), and (b) use of a single working solution, which, refrigerated, is stable for one month. The method is reliable, yields results that compare closely with those of the classical Jendrassik--Gróf method, is suitable for routine use, and lends itself to automation.

Ruthenium red effect on mechanical and electrical properties of mammalian skeletal muscle

In this work we studied the effect of ruthenium red (RR) on the mechanical and electrical properties of rat diaphragm bundles in vitro (30 degrees C). Two concentrations of RR were used: 5 and 10 microM. We measured: 1) twitches, tetanus and caffeine contracture; 2) relation between mechanical tension and resting membrane potential (Vm); 3) contraction threshold by visualization of the contraction around the stimulated area of the fiber. The main finding are the following: a) RR potentiates the twitch tension. The tetanic tension is not affected and the time course of the caffeine contracture is shortened in the RR containing solutions; b) the relationship between mechanical tension and resting membrane potential (Vm) is shifted toward more negative values of Vm in RR; c) the mechanical threshold is lowered about 7 mV in the presence of RR; d) the rates of depolarization and repolarization of the action potential are decreased in the test solutions. We suggested that the shift in the mechanical threshold and the prolongation of the action potential are the main factors involved in the potentiating effect of RR. The mechanism by which RR shifts the mechanical threshold is not known.

Malignant hyperthermia in plastic surgery

Malignant hyperthermia is a seemingly rare genetic myopathy. Hypermetabolic crisis accompanied by a rise in body temperature to as high as 44 degrees C is its hallmark. Malignant hyperthermia is usually triggered by potent inhalated anesthetics and/or depolarizing muscle relaxants. Because of the extraordinary risk of death in patients who are at risk, plastic surgeons may be reluctant to operate on these patients. Five such patients were referred to the Plastic Surgery Service and the UCLA Malignant Hyperthermia Center for anesthetic and surgical management following plastic surgical procedures aborted for first episodes of malignant hyperthermia. They were anesthetized with nitrous oxide, barbiturates, opiates, tranquilizers, and nondepolarizing muscle relaxants. The patients were not treated prophylactically with dantrolene. Cardiac monitoring, end-tidal pCO2, and rectal temperatures were followed. After completion of their plastic surgical procedures, all five patients had a vastus lateralis muscle biopsy performed and subsequent caffeine/halothane contracture studies completed. The contracture study was positive in all patients studied. No anesthetic or surgical complications were encountered. This study demonstrates that patients at risk of developing malignant hyperthermia crisis can have plastic surgical procedures performed safely while undergoing appropriately selected general anesthesia.