Mutations at the Arabidopsis CHM locus promote rearrangements of the mitochondrial genome

Nuclear recessive mutations at the chloroplast mutator (CHM) locus of Arabidopsis produce a variegated phenotype that is inherited in a non-Mendelian fashion. Molecular analysis of the cytoplasmic genomes of variegated plants from two independent chm mutant lines, using specific chloroplast and mitochondrial probes, showed that the chm mutations reproducibly induce the appearance of specific new restriction fragments in the mitochondrial genome. The presence of these restriction fragments cosegregated with the variegated phenotype in the progeny of crosses between mutant and wild-type plants. Sequence analysis of one of the new restriction fragments found in the variegated plants suggested that it was the product of a rearrangement event involving regions of the mitochondrial genome. Thus, it appears that the CHM locus may encode a protein involved in the control of specific mitochondrial DNA reorganization events.

The distribution of 5-methylcytosine in the nuclear genome of plants

We have determined the 5-methylcytosine (5mC) content in high molecular weight DNA, from two dicot (tobacco and pea) and two monocot (wheat and maize) plant species, fractionated according to base composition. The results show that the proportion of 5mC in the genomic fractions increases linearly with their guanine + cytosine (G + C) content while the proportion of non-methylated cytosine remains almost constant. This can be interpreted as a consequence of a difference in mutation pressure related to spontaneous deamination of 5mC to thymine between the different compartments of plant genomes.

Topography of mobility and complexity parameters of the EEG in Alzheimer's disease

Mobility and complexity, Hjorth's parameters of the electroencephalogram (EEG), were calculated in 16 electrodes in a group of 14 patients with probable Alzheimer's disease (AD) and 14 healthy controls. Mobility was decreased in the AD group, differences reaching high levels of significance over all the electrodes. Complexity was increased significantly in the AD group only in five electrodes. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for mobility at each electrode, considering only those AD patients with the lowest cognitive impairment. Sensitivity and negative predictive value were 100% at all the electrodes. Specificity and positive predictive value at several electrodes reached highly acceptable proportions, such as 71% or more for the former, and 64% or more for the latter. Implications of mobility in the early diagnosis of AD are discussed.

[Urinary incontinence in the elderly: clinical and urodynamic review of 195 cases]

One hundred ninety-five male and female patients over 65 years old presenting with urinary incontinence were evaluated by clinical and urodynamics. Urinary incontinence was in the form of urgency-incontinence in 68% of the cases, incontinence at cough in 26%, and urinary incontinence which the patient referred to no specific situation in 6%. Among the different urodynamics data, bladder instability was the most common (73%). Urinary stress incontinence was observed in 35% of the cases. Bladder instability was demonstrated in 77% of the cases with urgency-incontinence and in 69% of the cases with incontinence not referred to a specific situation. All the male patients with lower urinary tract obstruction had urgency-incontinence. Stress incontinence was demonstrated in 60% of the cases with incontinence at cough. Stress incontinence was not observed in male patients without associated diseases. The associated neurological disorder was accompanied by bladder hyperreflexia in 90% of the cases. A prior adenomectomy or hysterectomy was associated with a greater number of cases with stress urinary incontinence, accounting for 62% in both males and females.

Topographic maps of brain electrical activity in primary degenerative dementia of the Alzheimer type and multiinfarct dementia

The topography of the electroencephalographic (EEG) pattern of ten patients with primary degenerative dementia of the Alzheimer type, ten multiinfarct dementia patients, and ten age-matched controls was compared during three different behavioral conditions: resting condition with eyes open (EO), memorizing a list of words (M), and recalling the same list of words (R). Results indicate that the alpha frequency band does not show significant changes. On the other hand, the theta band could be considered an important factor in the differential diagnosis of the primary degenerative dementia of the Alzheimer type, showing a higher power over right posterior regions in this group of patients compared with the multiinfarct dementia patients under different behavioral conditions.

Placebo-controlled trial of nimodipine in the treatment of acute ischemic cerebral infarction

Nimodipine is a 1,4-dihydropyridine derivative that shows a preferential cerebrovascular activity in experimental animals. Clinical data suggest that nimodipine has a beneficial effect on the neurologic outcome of patients suffering an acute ischemic stroke. Our double-blind placebo-controlled multicenter trial was designed to assess the effects of oral nimodipine on the mortality rate and neurologic outcome of patients with an acute ischemic stroke. One hundred sixty-four patients were randomly allocated to receive either nimodipine tablets (30 mg q.i.d.) or identical placebo tablets for 28 days. Treatment was always started less than or equal to 48 hours after the acute event. The Mathew Scale, slightly modified by Gelmers et al, was used for neurologic assessment. Mortality rate and neurologic outcome after 28 days were used as evaluation criteria. We considered 123 patients to be valid for the analysis of efficacy. Mortality rates did not differ significantly between groups. Neurologic outcome after 28 days of therapy did not differ between groups. However, when only those patients most likely to benefit from any intervention (Mathew Scale sum score of less than or equal to 65 at baseline) were analyzed separately in post hoc-defined subgroups, the nimodipine-treated subgroups showed a significantly better neurologic outcome. This result suggests that some patients with acute ischemic stroke will benefit from treatment with nimodipine tablets.

Hyperoxia decreases lung size of amphibian tadpoles without changing GSH-peroxidases or tissue peroxidation

1. During the development of D. pictus larvae (Amphibia) in normoxia, selenium (Se) GSH-Px increased whereas non-Se GSH-Px did not change. 2. Acclimation to 60 or 100% O2 did not change Se GSH-Px or non-Se GSH-Px. 3. Hyperoxia did not change tissue peroxidation (TBA-RS) confirming the good capacity of D. pictus tadpoles for O2-adaptation. 4. Since hyperoxic induction of catalase (CAT) has been previously described in D. pictus tadpoles, it is concluded that CAT is more important than both GSH-Px for the establishment of O2-adaptation. 5. Increases of Se GSH-Px, SOD and CAT, are probably important for adaptation to the change from aquatic to aerial environment during metamorphosis in normoxia. 6. Chronic exposure to 100% O2 enormously reduced the lung size of D. pictus larvae.

Effect of hyperoxia acclimation on catalase and glutathione peroxidase activities and in vivo peroxidation products in various tissues of the frog Rana ridibunda perezi

Among vertebrates, adult amphibians are known to be especially tolerant to exposure to high environmental oxygen tensions. To clarify the basis for this high O2 tolerance, adult Rana ridibunda perezi frogs were acclimated for 15 days to water-air phases with either 149 mm Hg O2 (normoxia) or 710 mm Hg O2 (hyperoxia). At the end of the acclimation, various morphometric and biochemical parameters related to oxidative stress were measured in seven organs and tissues. Hyperoxia acclimation did not change either the total weight of the animals or the total and relative wet weights of the organs studied, except for the brain, which showed weight increases in the hyperoxic group. In vivo tissue peroxidation increased in the kidney; decreased in the skeletal muscle and skin; and did not change in the liver, lung, brain, and heart after hyperoxic exposures. Whereas liver, lung, and skin showed glutathione peroxidase (GSH-Px) activities with both cumene hydroperoxide (cumene-OOH) and H2O2 as substrates, skeletal muscle only showed H2O2 GSH-Px activity. Hyperoxia acclimation did not change either catalase (CAT) or GSH-Px activities in any organ, except for the liver in which CAT activity was induced by hyperoxia. Thus hyperoxia tolerance in this species does not need the induction of H2O2-detoxifying enzymes in the majority of the organs. It is suggested that the high O2 tolerance of this amphibian species is related to its comparatively high constitutive GSH-Px activities.

Physiological significance of catalase and glutathione peroxidases, and in vivo peroxidation, in selected tissues of the toad Discoglossus pictus (Amphibia) during acclimation to normobaric hyperoxia

1. Various parameters related to oxidative stress were measured in adult Discoglossus pictus acclimated for 15 days to either normoxia or hyperoxia (PO2 = 710 mmHg). 2. Total weight of the toads and total and relative wet weight of liver, kidneys, lungs and heart were not changed by hyperoxic acclimation. 3. In vivo tissue peroxidation increased in lung, decreased in skeletal muscle, and was not changed in liver, kidney, heart and skin after hyperoxic exposure. 4. Hyperoxic acclimation increased catalase activities in the lung, liver, kidney and heart but not in skeletal muscle and skin. 5. Liver showed higher GSH-peroxidase activity with cumene-OOH than with H2O2 as substrate, whereas lung, skeletal muscle and skin presented similar GSH-peroxidase activities with both substrates. 6. GSH-peroxidase activities did not change between hyperoxic and normoxic animals in liver, lung, skeletal muscle and skin. 7. These results show that catalase, not GSH-peroxidase, is the principal H2O2 detoxifying enzyme involved in the adaptation of D. pictus to hyperoxia.

Different levels of hyperoxia reversibly induce catalase activity in amphibian tadpoles

Studies about the proposed antioxidant physiological role of the catalase (CAT) enzyme in relation to different environmental oxygen tensions are reported for the first time in amphibian larvae of Discoglossus pictus and Rana ridibunda perezi during their development. The CAT levels of whole tadpoles increased constantly in both species during the larval period, reaching a maximum during the metamorphic climax. All through development, CAT activity levels were always greater in D. pictus than in R. ridibunda perezi. This correlates well with the already reported higher SOD activity and hyperoxia resistance of the D. pictus species when compared to R. ridibunda perezi. Long-term acclimation to different levels of hyperoxia (40, 60, and 100% O2) showed dose-related increases in the CAT activity of D. pictus tadpoles. These increases did not take place when the animals were subjected to acute hyperoxia (24 h). The increase in CAT activity observed after 15 days of acclimation to acute hyperoxia (710 mm Hg: 100% O2) was reversed after 15 additional days of postacclimation to normal air (149 mm Hg O2). When recently metamorphosed frogs were acclimated to acute hyperoxia, significant increases in CAT activity were observed after 15 days, but not after 7 days. The results are interpreted as supporting a protective role for the CAT enzyme in amphibian larvae and froglets against oxygen toxicity.

Catalase enzymatic activity and electrophoretic patterns in adult amphibians--a comparative study

Catalase electrophoretic patterns and enzymatic activities were measured in four organs of two anuran species, Rana ridibunda perezii and Discoglossus pictus. The D. pictus enzyme appeared as two distinguishable bands, whereas R. ridibunda catalase was monomorphic. Electrophoretic mobility of the major D. pictus catalase band was greater than that of R. ridibunda. Enzymes from both species showed slower mobility than that from bovine liver. Catalase activities did not show significant differences according to sex in any of the organs tested in R. ridibunda. Enzyme activities were similar in liver, kidney and brain when both species were compared. Only the heart showed much higher activity in D. pictus than in R. ridibunda. The catalase activity levels followed the order: liver greater than kidney greater than heart in both species. The heart showed higher activity than the brain in D. pictus but not in R. ridibunda.

Time dependency of adriamycin and adriamycinol kinetics

Adriamycin was administered by IV injection to seven patients with various solid tumors at a dose of 30 mg/m2 during successive courses. Extraction was carried out by the SEP-PAK method for plasma and by solvents for urine. Plasma and urinary levels of adriamycin and adriamycinol were determined by high-performance liquid chromatography over 72-h period after injection. Pharmacokinetic parameters for adriamycin and adriamycinol were calculated for each course of treatment. The results show significant inter- and intra-individual variations in the kinetics and elimination of both compounds. The analysis of pharmacokinetic data reveals a wide variability in the fluctuations observed during the successive courses in different patients. This study confirms the time-dependency of ADR kinetics.

Quantitation of adriamycin in plasma and urine: Comparative study of radioimmunoassay and high-performance liquid chromatography methods

The response of tumours to adriamycin, and the cardiotoxicity of the drug, may be related to its pharmacokinetics and plasma levels. Rapid and sensitive methods of adriamycin determination in plasma and urine samples are thus needed. A comparative study shows that high-performance liquid chromatography with fluorimetric detection is a reliable and specific method, but it is relatively slow and sometimes lacks sensitivity. A commercially-available radioimmunoassay kit is convenient, but there is a cross reaction with the major metabolise adriamycinol and unless the assay is combined with an extraction step, it gives erroneously high results.

Clearance of sensitized erythrocytes in NZB/NZW mice. Effects of castration and sex hormone treatment

The clearance of particulate immune complexes consisting of erythrocytes sensitized with IgG or complement was investigated in (NZB x NZW)F1 (B/W) mice. Treatment of castrated B/W mice with androgen or estrogen was able to modulate this clearance. Young (3-month-old) male and female B/W mice cleared IgG-sensitized mouse erythrocytes rapidly, whereas older males (13 months) and females (7 months) showed a marked impairment in their ability to clear these cells. In addition, erythrocytes sensitized with complement in the absence of antibody were cleared within 5 min in young B/W mice. Older mice showed a greater and more rapid clearance rate of these cells. Castrated female B/W mice treated with androgen implants from three weeks of age showed improved clearance of IgG-sensitized erythrocytes at 7 months, whereas estrogen-treated male mice showed delayed clearance. These results suggest an age-dependent defect in the clearance of IgG-sensitized particles, perhaps due to diminished levels of serum complement and/or saturation of Fc receptors. In addition, there is an alteration in the clearance of complement-sensitized erythrocytes which may be related to changes in macrophage activity or enzyme inactivators of C3 and C4. The possible mechanisms responsible for the hormonal modulation of clearance are discussed in relation to the known ability of these hormones to influence autoimmune diseases.

Feminizing adrenocortical carcinoma in a postmenopausal woman

The successful surgical removal of a feminizing adrenal tumour in a postmenopausal woman is described. Most of these tumours are malignant and the pathological findings and the biological behaviour of the tumour frequently do not correlate, so that a careful follow-up is necessary. In the presence of vaginal bleeding in a postmenopausal woman endometrial carcinoma should be considered. If this has been ruled out and if oestrogens are elevated with low plasma gonadotrophins, a feminizing ovarian or adrenal tumour should be considered.

Adrenal cysts: diagnostic value of "intravenous viscerogram"

Two cases of adrenal pseudocysts are presented, one secondary to the necrosis of an adenoma and the other a hemorrhagic pseudocyst. The diagnosis of these tumors is usually made radiologically owing to the vagueness of symptoms and nonexistent specific laboratory examinations, so that preoperative diagnosis is uncommon. We present a radiologic technique, intravenous viscerogram, which may be useful in the diagnosis of adrenal cysts. This procedure is easy to carry out and has almost no complications for the patient. The classification, clinical findings, and surgical treatment of adrenal cysts are discussed.