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Virus particles that infect eukaryotic cells can take advantage of the cytoskeleton and associated motors to translocate through the cytoplasm. Depending on the virus, motor proteins are recruited or, alternatively, cytoskeletal elements are induced to polymerize onto viral structures. Here we review recent advances toward understanding the roles of the cytoskeleton in virus trafficking.
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To evaluate the effects of severe, unilateral main-stem malignant bronchial obstruction on airway dynamics, we obtained maximal expiratory flow-volume (MEFV) curves in 11 patients 59 +/- 18 yr of age (mean +/- 1 SD), three with and eight without underlying emphysema, before and after laser therapy (10 patients) or lung resection (one patient). Mean main-stem bronchial diameters before and after treatment were 1.1 +/- 1.3 and 9.0 +/- 0.8 mm, respectively (p less than 0.05). In the three patients with underlying emphysema, MEFV curves showed a diffuse intrathoracic obstructive pattern before and after treatment; in the other eight patients, MEFV curves demonstrated an apparently restrictive pattern, with associated airflow obstruction in four, reversible after laser treatment in three of these four. After treatment, all patients exhibited an increase in FVC with a roughly parallel shift of the MEFV curve and little change in the slope of the descending limb of the MEFV curve: FVC improved from 54 +/- 16 to 86 +/- 13% predicted in patients without emphysema and from 54 +/- 16 to 77 +/- 8% predicted in patients with emphysema, whereas the slope of the descending limb of the MEFV curve between 45 and 55% of FVC changed minimally from 2.0 +/- 0.6 to 1.8 +/- 0.5 s-1 in patients without emphysema and from 0.8 +/- 0.3 to 0.8 +/- 0.1 s-1 in patients with emphysema.(ABSTRACT TRUNCATED AT 250 WORDS)
Twenty-three patients taking lithium carbonate alone in therapeutic dosage for a mean period of 43 months (range 6--108 months) and 23 control subjects matched for age and sex had the frequency and amplitude of postural tremor measured and extrapyramidal symptoms assessed by standard techniques. Patients on lithium had a significantly lower peak frequency of tremor than control subjects (P less than 0.05) and significantly greater extrapyramidal symptoms (P less than 0.01), indicating that tremor appearing after chronic lithium therapy is likely to be an extrapyramidal symptom. Such symptoms are common long-term adverse effects of lithium carbonate.
The aerobic and anaerobic energy yield during professional training sessions ("classes") of classical ballet as well as during rehearsed and performed ballets has been studied by means of oxygen uptake, heart rate, and blood lactate concentration determinations on professional ballet dancers from the Royal Swedish Ballet in Stockholm. The measured oxygen uptake during six different normal classes at the theatre averaged about 35-45% of the maximal oxygen uptake, and the blood lactate concentration averaged 3 mM (N = 6). During 10 different solo parts of choreographed dance (median length = 1.8 min) representative for moderately to very strenuous dance, an average oxygen uptake (measured during the last minute) of 80% of maximum and blood lactate concentration of 10 mM was measured (N = 10). In addition, heart rate registrations from soloists in different ballets during performance and final rehearsals frequently indicated a high oxygen uptake relative to maximum and an average blood lactate concentration of 11 mM (N = 5). Maximal oxygen uptake, determined in 1971 (N = 11) and 1983 (N = 13) in two different groups of dancers, amounted to on the average 51 and 56 ml X min-1 X kg-1 for the females and males, respectively. In conclusion, classical ballet is a predominantly intermittent type of exercise. In choreographed dance each exercise period usually lasts only a few minutes, but can be very demanding energetically, while during the dancers' basic training sessions, the energy yield is low.
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Diabetic neuropathy is a very common complication of diabetes mellitus, and animal studies have contributed tremendously to its understanding. The aim of this study was to estimate the neuropathic alterations in the Otsuka Long-Evans Tokushima fatty (OLETF) rats, an animal model of human type 2 diabetes mellitus. For this purpose, four groups of animals were used: untreated OLETF rats, sucrose-fed for 2 months OLETF rats, untreated Long-Evans Tokushima Otsuka (LETO) nondiabetic rats as genetic controls of OLETF, and sucrose-fed LETO rats. All were examined at baseline, at the end of the sucrose treatment, and during a washout period. The following parameters were evaluated: motor nerve conduction velocity (MNCV), sensitivity to noxious thermal and mechanical stimuli using the tail-flick (TF) and tail-pressure (TP) tests, and blood glucose (BG) and HbA1c levels. Our results showed that BG and HbA1c were significantly higher in OLETF rats when compared with those in control LETO rats. Sucrose caused remarkable increase of BG and HbA1c in the OLETF rats, but not in the sucrose-fed LETO rats. MNCV and thermal nociception significantly decreased in OLETF rats in their 10th month, while the values of the TP test did not differ compared with those from LETO rats. Sucrose administration significantly decreased the MNCV, and increased the pain threshold evaluated by the TF and TP tests, compared with those in the control OLETF rats. The studied parameters were not significantly altered in sucrose-fed LETO rats. In conclusion, our findings show that signs of diabetic neuropathy appear late in the individual development of the OLETF rats, and MNCV and thermal nociception are selectively affected in this strain. Sucrose deteriorated the diabetic state, decreased MNCV, and caused thermal and mechanical hypoalgesia.
A rice pse(t) (premature senescence, tentatively) mutant line, was isolated from 4,500 independent T-DNA inserted transgenic lines. The symptoms of premature senescence appeared more severely than those of the control plants (Zhonghua 11, japonica) at the last development stage. To characterize the mutant and provide basic information on the candidate genes by mapping to a physical region of 220-kb, experiments were carried out in two phytotrons under controlled temperature of 24 degrees C and 28 degrees C, respectively. The content of chlorophyll, soluble protein and MDA (malondialdehyde), net photosynthesis, the antioxidant enzyme activities of SOD (superoxide dismuase) (EC 1.15.1.1) and POD (peroxidase) (EC 1.11.1.7) and the peptidase activities of leaves were measured from top to bottom according to the leaf positions at the flowering stage. Compared with the control plant, the mutant showed the following characteristics: (1) Higher net photosynthesis rate (P(n)) appeared in the 1st and 2nd leaves, contents of chlorophyll and soluble protein were also higher in the 1st leaf; (2) The activities of SOD, POD and peptidase were higher according to the leaf position from top to bottom; (3) The symptom of premature senescence was accelerated in the mutant at 28 degrees C treatment. The MDA content and the SOD and POD activities between the 24 degrees C and 28 degrees C treatment mutants were not significantly different. Content of chlorophyll and soluble protein of leaves mutant decreased rapidly at 28 degrees C treatment. The results show that pse(t) is sensitive to high temperature. The probable function of PSE(T) is discussed.
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This review focuses on the properties of ferric iron surface receptors of Gram negative bacteria. We discuss the different strategies to acquire iron, and the fundamental role of these receptors in pathogenicity. The structure of some of these receptors, iron transport and regulation mechanisms are presented here.
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A study was performed to establish the dynamic behavior in situ of the descending aorta in the human fetus. The pulsatile movements of the vessel walls were recorded in 36 clinically normal fetuses using a real-time phase-locked ultrasonic system measuring echo movements with high spatial and temporal resolution. The mean amplitude of the diameter pulsations was similar in the 28th - 35th week to that in the 36th - 40th week but, as the apparent diastolic diameter increased, the pulse-elicited increment of the cross-sectional area was 29% larger in the older group. The diastolic diameter decreased (p less than 0.001) and the amplitude of the diameter pulsation increased (p less than 0.001) with prolongation of the previous beat interval. The diameter pulse velocity was positively correlated to gestational age (p less than 0.001), ranging between 1.35 and 2.89 m/sec. The incremental phase of the pulse curve diminished in duration with increasing distance from the heart (p less than 0.001) and with decreasing duration of the previous beat interval (p less than 0.001). The maximum slope of the incremental phase was higher in the more distal part of the aorta (p less than 0.001). The study demonstrates that the diameter pulses contain useful information on the cardiovascular dynamics and provides evidence that the Frank-Starling mechanism is effective also in the human fetus.
The spatial distribution of nerve fibers from individual vestibular end organs in the vestibular ganglia (VG) was studied using horseradish peroxidase (HRP). HRP was injected into the cut end of the bull frog ampullary nerve. Stained neural elements were counted on the serial sections. Spatial distribution was also studied by recording ampullary nerve compound action potentials (AP) from VG. The anterior semicircular canal (SC) nerves were distributed in the anterior half of VG. The horizontal SC nerves were also distributed in the anterior half of VG, but tended to be posterior. The posterior SC nerves were found predominantly in the posterior half and antero-dorsal portions. These distribution patterns corresponded well with those confirmed by AP recording. There were a few neural connections between anterior and posterior SC, or horizontal and posterior SC, indicating receptor-receptor fibers.
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Aerobic or anaerobic degradation of glucose by Streptococcus dysgalactiae and Streptococcus uberis yielded products qualitatively similar to those observed previously for Streptococcus agalactiae. There were, however, quantitative differences. Though acetoin was formed during aerobic growth of Streptococcus uberis, there was none with Streptococcus dysgalactiae. Differences between Streptococcus dysgalactiae and Streptococcus uberis in their aerobic metabolism of glucose was in lower oxygen consumption (.5 mol/mol of glucose), greater conversion of glucose to lactic acid, and lower molar growth yields with Streptococcus uberis. Cell suspensions of Streptococcus uberis had strong peroxidase activity, and no hydrogen peroxide accumulated during the respiration on glucose. With Streptococcus dysgalactiae, there was more oxygen consumed during growth (1.5 mol/mol of glucose used), greater conversion of glucose to acetic and formic acids and carbon dioxide, and a cell yield of about 6 g of dry cells more per mole of glucose than with Streptococcus uberis. This increase in molar growth yield with Streptococcus dysgalactiae over Streptococcus uberis could be nearly all accounted for by differences in the amount of substrate level adenosine triphosphate generated. Cell suspensions oxidizing glucose accumulated hydrogen peroxide and showed no peroxidase activity. Streptococcus dysgalactiae showed the same growth relationships in three milk media as Streptococcus agalactiae, although growth and acid formation values were much lower. Growth inhibition by the lactoperoxidase complex was reversed with cystine. Acid formation by Streptococcus uberis was decreased by the lactoperoxidase complex and increased by the addition of cystine; however, neither appeared to affect the growth of the organism.
Since animals are under constant threat of starvation, storage of energy sources inside the body is essential for various activities. Therefore, animals exhibit highly sophisticated mechanisms for storing energy inside their bodies in adipose tissue. However, in humans it has been clarified that fat cell (adipocyte, which comprises adipose tissues) differentiation and the extent of subsequent fat accumulation (hypertrophy of cells) are closely associated with the occurrence and advancement of various diseases resulting from obesity. Moreover, progress in biochemical studies with respect to adipocyte in recent years has rapidly clarified new functions and differentiation mechanisms of adipocytes. Interesting points, in particular, are the function of white adipocytes as "secreting cells" and the molecular mechanism of adipocyte differentiation via the nuclear receptors. Consequently, adipose tissue is being targeted to prevent or treat many common diseases. This paper summarizes recent knowledge on characteristics, differentiation and proliferation of adipocytes and the mechanisms by which adipocytes are regulated.
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