Inactive Atm abrogates DSB repair in mouse cerebellum more than does Atm loss, without causing a neurological phenotype

The genome instability syndrome, ataxia-telangiectasia (A-T) is caused by null mutations in the ATM gene, that lead to complete loss or inactivation of the gene's product, the ATM protein kinase. ATM is the primary mobilizer of the cellular response to DNA double-strand breaks (DSBs) - a broad signaling network in which many components are ATM targets. The major clinical feature of A-T is cerebellar atrophy, characterized by relentless loss of Purkinje and granule cells. In Atm-knockout (Atm-KO) mice, complete loss of Atm leads to a very mild neurological phenotype, suggesting that Atm loss is not sufficient to markedly abrogate cerebellar structure and function in this organism. Expression of inactive ("kinase-dead") Atm (Atm^KD) in mice leads to embryonic lethality, raising the question of whether conditional expression of Atm^KD in the murine nervous system would lead to a more pronounced neurological phenotype than Atm loss. We generated two mouse strains in which Atm^KD was conditionally expressed as the sole Atm species: one in the CNS and one specifically in Purkinje cells. Focusing our analysis on Purkinje cells, the dynamics of DSB readouts indicated that DSB repair was delayed longer in the presence of Atm^KD compared to Atm loss. However, both strains exhibited normal life span and displayed no gross cerebellar histological abnormalities or significant neurological phenotype. We conclude that the presence of Atm^KD is indeed more harmful to DSB repair than Atm loss, but the murine central nervous system can reasonably tolerate the extent of this DSB repair impairment. Greater pressure needs to be exerted on genome stability to obtain a mouse model that recapitulates the severe A-T neurological phenotype.

AN-7, a butyric acid prodrug, sensitizes cutaneous T-cell lymphoma cell lines to doxorubicin via inhibition of DNA double strand breaks repair

We previously found that the novel histone deacetylase inhibitor (HDACI) butyroyloxymethyl diethylphosphate (AN-7) had greater selectivity against cutaneous T-cell lymphoma (CTCL) than SAHA. AN-7 synergizes with doxorubicin (Dox), an anthracycline antibiotic that induces DNA breaks. This study aimed to elucidate the mechanism underlying the effect of AN-7 on Dox-induced double-strand DNA breaks (DSBs) in CTCL, MyLa and Hut78 cell lines. The following markers/assays were employed: comet assay; western blot of γH2AX and p-KAP1; immunofluorescence of γH2AX nuclear foci; Western blot of repair protein; quantification of DSBs-repair through homologous recombination. DSB induction by Dox was evidenced by an increase in DSB markers, and DSBs-repair, by their subsequent decrease. The addition of AN-7 slightly increased Dox induction of DSBs in MyLa cells with no effect in Hut78 cells. AN-7 inhibited the repair of Dox-induced DSBs, with a more robust effect in Hut78. Treatment with AN-7 followed by Dox reduced the expression of DSB-repair proteins, with direct interference of AN-7 with the homologous recombination repair. AN-7 sensitizes CTCL cell lines to Dox, and when combined with Dox, sustains unrepaired DSBs by suppressing repair protein expression. Our data provide a mechanistic rationale for combining AN-7 with Dox or other DSB inducers as a therapeutic modality in CTCL.

Monitoring the ATM-Mediated DNA Damage Response in the Cerebellum Using Organotypic Cultures

The ATM gene and its protein product, the ATM protein kinase, were identified as a result of attempts to understand the molecular basis of the genetic disorder, ataxia-telangiectasia (A-T). The cardinal symptom of A-T is neurodegeneration expressed primarily as progressive cerebellar atrophy. A major tool in the investigation of ATM functions in the cerebellum is cerebellar organotypic cultures, which allow cerebellar slices to live in culture for several weeks without losing their viability and organization. These cultures are amenable to various treatments and manipulations and provide a close look at Purkinje cells in their almost natural environment. We optimized the protocol for establishing and maintaining these cultures and provide here examples of readouts of the DNA damage response in cerebellar organotypic cultures treated with a DNA-damaging agent.

Dentin micro-architecture using harmonic generation microscopy

OBJECTIVES

We present a novel way to create high-resolution three-dimensional images of tooth dentin by harmonic generation scanning laser microscopy.

METHODS

The images were taken using a pulsed infrared laser. Three-dimensional reconstruction enables the visualization of individual tubules and the collagen fibrils mesh around them with an optical resolution of approximately 1 microm.

RESULTS

The images show micro-morphological details of the dentinal tubules as well as the collagen fibrils at a depth of up to about 200 microm. The data show that while collagen fibrils are organized in planes perpendicular to the tubules, close to the dentin enamel junction they lie also along the long axis of the tubules.

CONCLUSIONS

The unique 3D information opens the opportunity to study the collagen fibril arrangement in relation to the tubule orientation within the dentin matrix, and may be applied to study the micro-morphology of normal versus altered dentin.

Transformation from an ultrashort pulse to a spatiotemporal speckle by a thin scattering surface

We have theoretically and experimentally studied the local temporal and spectral characteristics of an ultrashort pulse passing a simple thin diffusive element. We show that as one moves away from the diffuser the pulse evolves into a spatiotemporal speckle.

Femtosecond pulse-shape modulation at nanosecond rates

We report high-rate, computer-controlled femtosecond pulse shaping by use of an electro-optical gallium arsenide optical phased-array modulator with 2304 controlled waveguides. It provides fast modulation speed of both spectral phases and amplitudes. Limited by the driving electronics of our current setup, we were able to update a pulse shape in approximately 30 ns. This technique paves the way toward individual shaping of every single pulse of typical femtosecond mode-locked oscillators.

The effectiveness of midazolam and hydroxyzine as sedative agents for young pediatric dental patients

The purpose of the study was to compare hydroxyzine (HYD) and 0.2mg/Kg midazolam (MDZ) as sedative agents for young pediatric dental patients. Twenty-nine healthy two-to-four-year-old children participated in the study. Hydroxyzine was dripped nasally 10 minutes before treatment. The patient's crying, alertness, movement and general behavior were blindly assessed and statistically analyzed. No differences were found between the mean general behavior scores nor between the first and second visits in both groups. A significant difference (p < 0.02) was found in the acceptance of the face and nasal masks by children of the midazolam group between the first and second appointments. None of the children of this group cried nor moved at the first visit. The results of the study indicate that midazolam is somewhat more effective than hydroxyzine as a sedative agent for short procedures in young pediatric dental patients.

Cyclohexyladenosine reduces MPTP induced tremor in dogs

Male dogs were injected i.v. with 1 methyl-4-phenyl-1,2,3,6-tetrahydro- pyridine (MPTP) 2.5 mg/kg twice with an interval of 6 days. Twenty minutes after MPTP injection cyclohexyladenosine (CHA) 1 mg/kg i.v. was injected. Ten minutes after CHA injection the MTPT induced tremor, tachycardia and salviation ceased.

The predictive value of fetal breathing movement and Bishop score in the diagnosis of "true" preterm labor

In 70 patients who were between 32 and 36 weeks' gestation and who complained of painful uterine contractions, real-time ultrasonography was performed to establish the presence or absence of fetal breathing. Ten of the 14 women in whom no fetal breathing movement could be detected were delivered of infants within 48 hours, whereas the pregnancies continued for a week or longer in 52 of the 56 patients in whom fetal breathing was present. There was a good correlation between Bishop score and pregnancy outcome. Of the 48 patients with "unfavorable" cervix (Bishop score less than or equal to 3), 45 were delivered of infants after 1 week or more, whereas of 22 patients with a Bishop score of 4 to 6, nine were delivered of infants within 48 hours and ten pregnancies continued for 1 week or more.

The effect of indomethacin, ibuprofen and paracetamol on the TRH induced TSH secretion in the rat

1. The response of TSH to TRH and the TRH content of the hypothalamus, following indomethacin, ibuprofen and paracetamol treatment, was measured in male rats. 2. Daily treatment of indomethacin (3 mg/kg)) for 3 days markedly reduced T4 concentration in the serum, the TRH content of the hypothalmus gland and inhibit Pituitary TSH response to the low T4 level in the blood. 3. Ibuprofen (12 mg/kg) and paracetamol (50 mg/kg) did not influence T4 or TSH levels of the serum nor the TRH content of the hypothalmus. 4. TRH-induced TSH secretion was not influenced by indomethacin, ibuprofen or paracetamol treatment.

Individual changes in T lymphocyte parameters of old human subjects

Parameters of peripheral blood T lymphocytes were determined repeatedly (twice, 2-4 weeks apart), in ten old (78 + 5) and compared to nine young (31 + 5) human subjects. Assays included percentage of total, helper, and suppressor, T lymphocytes, and the reaction to PHA stimulation for 24, 48, 72, and 96 h, as assessed by levels of proliferation and IL-2 production. A lower response to PHA was observed in the old as compared to the young, with no significant changes in T cell subsets. A marked variability was noted between the results of the first and second determinations of the response to PHA in each individual. The lack of correlation between the two determinations was more prominent in the old. Unresponsiveness to PHA throughout the incubation period, was noted in two old subjects, but, in only one of the two determinations. This transient unresponsiveness was not accompanied by any changes in their clinical state. Thus, establishments of the immune status of the aged should be based on at least two repeated determinations.

Morphine induced thyroxine release from rat thyroid gland in vitro

Male rat thyroid glands were incubated for two hours in Krebs-Ringer bicarbonate buffer with different amounts of morphine and/or naloxone. Five micrograms/ml morphine produced a significant increase in the T4 concentration of incubation medium, and resulted in an accumulation of cAMP in the tissue. Naloxone did not change the T4 release but its incubation with morphine prevented the morphine-induced changes. Similarly, naloxone inhibited the morphine-induced accumulation of cAMP in the thyroid tissue.

Short-term effect of morphine on the thyroid gland in male rats

Experiments were designed to demonstrate that morphine may exert a direct short-term effect on the hormone release of the thyroid gland. Groups of male rats were injected with single doses of 1, 5 and 10 mg/kg morphine, or with 2 mg/kg naloxone and in addition with morphine 30 min after naloxone and/or with naloxone 30 min after morphine pre-treatment. The rats were killed by decapitation 15, 30 and 60 min after the injection and serum was collected and stored for subsequent TSH, T4 and T3 radioassays. All doses of morphine resulted in an increase of serum T4 and T3 concentrations 15 and 30 min after the injection, with a tendency to return to control levels by the 60 min samples. Serum TSH concentrations were to suppressed by administration of 5 and 10 mg/kg but not by 1 mg/kg morphine. Naloxone treatment did not increase the T4 and T3 concentrations; however, serum TSH was elevated in the 15 min sample. Naloxone pre-treatment inhibited the morphine induced release of T4 and T3 into the serum, but naloxone administration after morphine pre-treatment failed to prevent the increase of T4 and T3 secretion. These data suggest that morphine may exert a short-term stimulatory effect on the thyroid gland with a concomitant inhibitory action on the hypothalamo-pituitary TSH system.

Correlation between 3',5', c-AMP levels and thyrotropin in separated rat pituitary thyrotropic cells

The correlation between 3',5', c-AMP levels, TSH content and secretion of separated thyrotropic cells was studied. Incubation of the separated cells with 1, 10 and 100 ng of TRH does not change the 3',5',c-AMP levels, despite the significant rises of the TSH level. Dibutyryl c-AMP causes rise in TSH content, with no indication of its secretion. PGE2 10(-5) increased 3'5',c-AMP levels with no change in the content or secretion of TSH in separated thyrotropic cells.

Effect of manual lymph drainage massage on urinary excretion of neurohormones and minerals in chronic lymphedema

Treatment of 29 cases of chronic lymphedema of various origins, mostly of the lower limbs, by manual lymph drainage massage resulted in significant changes of neurohormone excretion in the urine, whereas the secretion of 17-KS, thyroxine, minerals, and creatinine was not significantly changed. Comparison of the values of urinalysis before and after manual lymph drainage of the patients showed the following changes: 17-KS; -3.5% (non significant); 17-OH: -31% (significant); adrenaline: +50% (significant); noradrenaline: +19% (significant); serotonin: -22% (significant); 5-HIAA: +21% (significant); histamine: +129% (highly significant); thyroxine: -17% (nonsignificant); creatinine: -17% (nonsignificant); sodium: -1% (nonsignificant); potassium: -14% (nonsignificant). The corresponding values for ten controls were all non significant. These findings underline the importance of adrenaline and noradrenaline release by manual lymph drainage, which improves circulation. On the other hand, our results indicate the involvement of histamine and perhaps of serotonin in lymphedema formation, and suggest a combination of manual lymph drainage massage with antihistamine and antiserotonin treatment.

Separation of rat pituitary thyrotrophic cells

A method for the enrichment of live thyrotrophic pituitary cells is described. Pituitary glands of young male rats were removed into Earle's solution and dispersed in a 0.1% trypsin solution containing 0.5% bovine serum albumin, pH 7.2. Nylon fibres (25 microgram) were used for the separation of the thyrotrophic cells, by stringing them across a plastic frame which fitted a plastic Petri dish containing the cell suspension. The fibres were washed with light petroleum (b.p. 60--80 degree C) and carbon tetrachloride, hydrolysed with 3 M-HCL for 30 min at room temperature and washed with distilled water and phosphate-buffered saline (pH 7.2). The fibres were treated with thyrotrophin releasing hormone (TRH) alone or in the presence of soluble carbodiimide solution. After incubation for 1 h at room temperature, the fibres were transferred to a new Earle's medium and cells were released from the fibres by plucking them with a needle. The separated thyrotrophic cells were identified by radioimmunoassay and by electron microscopy. Using the above-mentioned methods, enrichment of thyrotrophic cells was obtained. Thus, the amounts of TSH, prolactin, LH and GH released, during 2 h of incubation, by 1.5 x 10(6) unseparated cells were 6.8 +/- 0.65, 4.1 +/- 0.47, 4.8 +/- 0.52 and 5.2 +/- 0.68 microgram respectively, while the same number of purified thyrotrophic cells released 76.1 +/- 0.42, 1.2 +/- 0.3, 0.6 +/- 0.35 and 1.6 +/- 0.22 microgram of the same hormones (means +/- S.E.M.).

An immunofluorescent method for identification of isolated thyrotropic cells

A sensitive and specific immunofluorescent method for identification of thyrotropic cells was developed. The TSH-producing cells were found to be heterogenic in their morphology and intensity of staining.

Suppression of prolactin and thyrotropin secretion in the rat by antiserum to thyrotropin-releasing hormone

Administration of antiserum to synthetic thyrotropin-releasing hormone (TRH) to male and female rats cause a 50% and a 70% suppression in serum levels of prolactin and thyrotropin, respectively, as compared with controls injected with normal rabbit serum. The degree of suppression was similar in diestrous and proestrous female rats and in male rats. These findings support the view that, in addition to its original designation, TRH also has a physiological role in regulating release of pituitary prolactin.

[New methods in the treatment of weather sensitivity]

Changing weather fronts produce severe changes of daily rhythms. Electrical impulses arrive 1-2 days before the weather and create either atmospherics or "positive ions". They are responsible for the epidemic appearance of migraine and of thrombo-embolism. The impact of atmospheric electricity has been assessed in 1000 patients by daily urinalysis of serotonin, 5-HIAA, adrenaline, noradrenaline, histamine, thyroxine, 17-KS, 17-OH, Na, K, creatinine and diureses. The changes found in these 12 parameters allowed a classification of heat reactions into three clinical entities: 1. serotonin hyperproduction causing a typical irritation syndrome: 2. adrenal deficiency producing a typical exhaustion syndrome; 3. hyperthyroidism "Forme fruste" with subclinical "apathetic" thyroid symptoms. These sufferings, typical for Föhn, Tramontana, Sirocco, Sharkiye, Chamssin, Sharav and Santa Ana Winds, are mainly due to positive ionisation of the air. They can be prevented by negative ionising apparatuses or specific drug treatment.

Adenyl cyclase activity at different environmental temperatures in the isolated rat anterior pituitary membranes

The effect of different environmental temperatures on adenyl cyclase was studied. An increase in temperature appears to increase TRH-induced activity of adenyl cyclase, and possible causes an increases sensitivity to the hormone. Cyclic AMP levels of the pituitaries showed change at different environmental temperatures.

Pituitary-thyroid interrelationship in rats exposed to different environmental temperatures

The present work intended to show interrelationships between triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH) and cyclic adenosine 3'5'-monophosphate (cyclic AMP) in both the pituitary and the thyroid. Experiments were carried out on animals exposed to 0 and 37 degrees C for 4 days and to 34 degrees C for 21 days. Control animals were maintained at 22 degrees C. T4 serum levels of 2.6, 4.0 1.1 and 0.42 mug/100 ml serum, and T3 levels of 95, 135, 65 and 36 ng/100 ml serum were recorded at 22, 0, 34 and 37 degrees C, respectively. The observed serum TSH levels were 265, 192, 237 and 182 mug/100 ml serum in rats exposed to 22, 0, 34 and 37 degrees C, respectively. Pituitary TSH content was similar at 22, 0 and 34 degrees C whereas the content in the 37 degrees C exposed rats was twice that of controls. Thyroid cyclic AMP levels were not significantly different among the various experimental groups. The content of cyclic AMP in the pituitary was higher at 34 degrees C by 125% and 37 degrees C by 240%, and lower at 0 degress C by 56% with regard to the control. These results suggest that the 0 and 34 degrees C exposed rats reach a new steady state in the control of thyroid hormones secretion rate. However, at 37 degrees C, the TSH-Thyroxine interrelationships seem to break down.

Effect of air ionization of blood serotonin in vitro

The effect of negative and positive air ionisation on siliconized blood serotonin was studied in vitro. The experiments showed that within 10 min positive ionisation increased serotonin levels in total blood (+40%), plasma (+90%), erythrocytes (+50%) and thrombocytes (+240%). On the other hand, negative ionization (10 min) lowered the serotonin content of total blood (-30%), plasma (-42.5%), erythrocytes (-41.7%) and thrombocytes (-72.3%), thus confirming the 'Krueger Effect' in vitro.

Dehydroepiandrosterone-induced thyrotrophin release during heat stress in rats

Six groups each of 12 male albino rats were reared from day 21 of life at temperatures of 23, 34 or 37 degrees C. While the rats survived for unlimited periods at 23 and 34 degrees C, the animals reared at 37 degrees C succumbed within 5 days to heat stress. The latter group, when injected s.c. or i.p. with 50 mg dehydroepiandrosterone (DHA)/kg/day were no longer affected by the heat. During this treatment thyroid epithelial cell height doubled, colloid decreased by 20%, connective tissue did not change, the basic metabolic rate decreased by 10% and rectal temperatures of the treated rats increased with the ambient temperatures. Body weight increased only slightly, pituitary TSH decreased by 25%, serum TSH increased by over 50%, thyroxine and 125I uptake increased by 200%. The survival of the DHA-treated rats was apparently secured by blocking the hypothalamic thermoreceptors.

Intermittent hyperthyreosis -- a heat stress syndrome

Intermittent hyperthyreosis occurs under various forms of stress, especially heat stress. The clinician may diagnose such cases as masked or apathetic hyperthyroidism or "forme fruste" hyperthyreosis or thyroid autonomy. As most routine and standard tests may here yield inconsistent results, it is the patients' anamnesis which may provide the clue. Our Bioclimatology Unit has now seen over 100 cases in which thyroid hypersensitivity towards heat was the most prominent syndrome: 10-15% of weather-sensitive patients are affected. The patients complain before or during heat spells of such contradictory symptoms as insomnia, irritability, tension, tachycardia, palpitations, precordial pain, dyspnoe, flushes with sweating or chills, tremor, abdominal pain or diarrhea, polyuria or pollakisuria, weight loss in spite of ravenous appetite, fatigue, exhaustion, depression, adynamia, lack of concentration and confusion. Determination of urinary neurohormones allows a differential diagnosis, intermittent hyperthyreosis being characterized by three cardinal symptoms: 1. tachycardia -- every case with more than 80 pulse beats being suspect (not specific); 2. urinary histamine -- every case excreting more than 90 mug/day being suspect. Again the drawback of this test is its lack of specificity, as histamine may also be increased in cases of allergy and spondylitis; 3. urinary thyroxine -- every case excreting more than 20 mug/day T-4 being suspect. This is the only specific test. Therapy should make use of lithium carbonate and beta-blockers. Propyl thiouracil is rarely required.