Endoglucanase A from Cellulomonas fimi in which the hinge sequence of human IgA1 is substituted for the linker connecting its two domains is hydrolyzed by IgA proteases from Neisseria gonorrhoeae

The hinge in IgA1 and the linker in endoglucanase A (CenA) are quite similar. The IgA1 hinge is 18 amino acids long and contains only proline, threonine and serine. The linker in CenA is 27 amino acids long and contains only proline, threonine and a single serine. IgA proteases from Neisseria gonorrhoeae cleave Pro-Ser and Pro-Thr bonds within the IgA1 hinge sequence, but they do not attack CenA. When the linker sequence of CenA is replaced with the hinge sequence of IgA1, the hybrid polypeptide is susceptible to the N. gonorrhoeae proteases. It is cleaved within the hinge sequence at the same sites as IgA1.

[Amphetamine--induced rage reaction in mice and its mechanism]

Rage reaction was induced in mice by ip amphetamine sulfate (APT) 15 mg/kg. Mice appeared hyperreactive after 6 min and then squeaked and fought each other. These manifestations were most distinct in 15-30 min and subsided after 40-70 min. At 20 degrees C and 25 degrees C, the occurrence of rage reaction was 85.0% and 90.0% respectively. The ED50 of APT for eliciting rage reaction was 11.8 +/- 2.1 mg/kg ip. No significant difference in the induction of rage reaction was observed between male and female mice but ambient temperature affected the occurrence of this reaction. Neuroleptic drugs (chlorpromazine, haloperidol, tardan and clozapine), anxiolytic drugs (diazepam and meprobamate) and reserpine suppressed the rage reaction induced by APT in mice. Phenobarbital and pentobarbital (at sedative doses), atropine, scopolamine, phentolamine and propranolol exerted no influence on APT--induced rage reaction. Amantadine, levodopa and apomorphine at lower doses potentiated the rage inducing effect of APT. Moreover, at higher doses amantadine or levodopa alone also evoked rage reaction similar to that induced by APT. Therefore, it may be deduced that the APT-induced rage reaction results from increased release of dopamine in limbic system and has nothing to do with the simultaneous epinephrine release. The available data indicate that the APT--induced rage reaction in mice deserves to be recommended as an animal model for screening potential neuroleptic drugs. The merits and shortcomings of this new model are discussed.

Myocardial calcium cycling defect in furazolidone cardiomyopathy

We have previously demonstrated that in furazolidone-induced congestive heart failure in turkeys the specific Ca(2+)-ATPase activity of myocardial sarcoplasmic reticulum (SR) is 60% increased in compensation for a 50% depression in net Ca(2+)-sequestration activity. This study tested the hypothesis that SR Ca(2+)-uptake and Ca(2+)-ATPase activities were uncoupled in this cardiomyopathy because of increased Ca(2+)-release channel activity. A novel microassay was used to monitor Ca2+ transport by myocardial homogenates using the fluorescent Ca2+ dye indo 1 to indicate extravesicular ionized Ca2+. The method is applied to cyropreserved biopsy specimens of myocardium and requires only 50 mg tissue. Both SR Ca(2+)-pump and SR Ca(2+)-channel activity were estimated using the channel-inhibitor ruthenium red (RR) and the mitochondrial inhibitor sodium azide. The specificity of the RR inhibition was confirmed using ryanodine. Cardiomyopathy was induced in 2-week-old turkey poults by the addition of 0.07% furazolidone to their feed for 4 weeks. Compared with controls, myocardial maximal Ca(2+)-channel activity relative to maximal Ca(2+)-pump activity was 22% greater and duration of Ca(2+)-channel activity was 100% increased. However, the heart failure birds had 43 and 53% decreases in absolute maximal Ca(2+)-pumping and Ca(2+)-channel activities, respectively. The abnormal Ca(2+)-channel activity resulted in 200% greater time before initiation of net Ca2+ sequestration and 700% greater final myocardial Ca2+ concentrations. For all birds, the Ca(2+)-accumulating activity was highly correlated with Ca(2+)-release activity (all p less than 0.05). These data indicate that in this animal model of congestive heart failure there is defective SR Ca(2+)-channel function resulting in abnormal Ca2+ homeostasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of mild cardiac hypertrophy, induced by volume overload in turkeys, on myocardial sarcoplasmic reticulum calcium-pump and calcium-channel activities and on the creatine kinase system

Recent studies indicate that in animals with marked cardiac hypertrophy, there is depressed function of Ca2+ sequestration by myocardial sarcoplasmic reticulum (SR) because of down regulation of the Ca(2+)-ATPase gene. However, in several animal models we have observed enhancement of myocardial Ca2+ sequestration in response to chronic cardiac stimulation. We tested the hypothesis that in animals with mild cardiac hypertrophy, there is enhanced Ca(2+)-cycling activity by the SR Ca2+ pump and Ca(2+)-release channel. Because creatine kinase activity is consistently decreased in cardiomyopathy, we also determined whether enhanced Ca2+ cycling was accompanied by down regulation or inhibition of the creatine kinase system. Mild cardiac hypertrophy was induced by volume overload; 2% salt was added to the diet of 2-week-old turkey poults for 4 weeks. Compared with age-matched controls, volume overload resulted in 14.3% increase in heart weight and 21.5% increase in heart-to-body weight ratios. The hypertrophied heart had approximately 20% increased activities of the SR Ca2+ pump and the SR Ca2+ channel. Net Ca2+ transport was increased by 16.5%. Compared with controls and in contrast to several other myocardial enzymes, creatine kinase activity was diminished in the hypertrophied hearts by 23% and creatine content was decreased by 8%. Differences between groups were not detected for lactate dehydrogenase, aspartate transaminase, and alanine transaminase. We concluded that an early adaptation of the myocardium undergoing hypertrophy in compensatory response to functional overload is an enhancement of Ca2+ cycling activity by the Ca2+ pump and Ca2+ channel of the SR.(ABSTRACT TRUNCATED AT 250 WORDS)

Deletion of the linker connecting the catalytic and cellulose-binding domains of endoglucanase A (CenA) of Cellulomonas fimi alters its conformation and catalytic activity

The Pro-Thr box is a linker of 23 amino acids ((PT)4T(PT)7) connecting the catalytic domain and the cellulose-binding domain (CBD) of endoglucanase A (CenA) from the bacterium Cellulomonas fimi. Deletion of the Pro-Thr box alters the conformation of CenA by changing the relative orientation of the catalytic domain and the CBD. The tertiary structures of the catalytic domain and the CBD appear to be unchanged. The change in conformation reduces the catalytic efficiency of the enzyme and masks one of two protease-sensitive sites between the domains. The deletion does not affect the adsorption of the enzyme to microcrystalline cellulose, but it does affect its desorption from cellulose. The results suggest that the Pro-Thr box in CenA has an extended, kinked, and rigid conformation.

[Effect of posture on pharyngeal area measured by acoustic reflection technique]

Patients with obstructive sleep apnea (OSA) have a smaller pharyngeal area (PA) and higher compliance than normal subjects. The apnea-hypopnea index (AHI) in OSA patients determined by polysomnographic study was greater in the supine than lateral position. Recently there have been reports of reduction in the PA by the acoustic reflection technique (ART) in the supine position. However, there has been no report on the PA measured by ART in the lateral position which is important in the treatment of OSA. To evaluate differences in the PA with posture changes, we measured the PA in 41 normal subjects (11 males and 30 females) in the sitting, lateral and supine positions by ART. The average PA in the sitting position in the males and females was 3.8 +/- 0.6 cm2, and 3.3 +/- 0.5 cm2, respectively. The average PA in the lateral position in the males and females was 3.5 +/- 0.6 cm2, and 3.1 +/- 0.5 cm2, respectively. The average PA in the supine position in the males and females was 2.9 +/- 0.5 cm2, and 2.7 +/- 0.4 cm2, respectively. PA in the sitting position correlated well with body surface area (BSA). The average PA in both the males and females was significantly smaller in the supine than in the sitting position. The average PA in the lateral position in both males and females was significantly smaller than that in the sitting position and was significantly larger than that in the supine position. Decrease in PA with posture (from sitting to lateral) in the males (9.2 +/- 5.5%) was similar to that in the female (5.7 +/- 5.4%). Decrease in PA with posture (from sitting to supine) was significantly larger in male (24.4 +/- 9.5%) than in female (16.6 +/- 6.8%). We conclude that the decrease of PA in the supine position is ameliorated in the lateral position in normal subjects. Lateral position may be the preferred sleeping position in snoring or OSA patients.

Myocardial Ca-sequestration failure and compensatory increase in Ca-ATPase with congestive cardiomyopathy: kinetic characterization by a homogenate microassay using real-time ratiometric indo-1 spectrofluorometry

A novel, simple, rapid and reproducible microassay is used for kinetic analysis of Ca-sequestration by homogenates of myocardium of turkeys with furazolidone-induced congestive cardiomyopathy. The assay monitors Ca in real-time using dual-emission ratiometric spectrofluorometry and the Ca-indicator dye indo-1. Using this assay and isolated SR studies we make several novel findings regarding the mechanism of SR failure in furazolidone cardiomyopathy. Qualitative differences in Ca-sequestration were not detected between groups. However, compared to controls the furazolidone treatment resulted in: 1) 50% depression in maximal activities (1.54 +/- 0.36 vs 0.73 +/- 0.12 microM/sec); 2) 2-fold increases in post-sequestration concentrations of ionized Ca (79 +/- 23 vs 141 +/- 13 nmol Ca/L homogenate); 3) 2-fold increases in Ca half-life (415 vs 790 msec); and 4) 25% increased passive Ca-binding capacity of homogenates. The Ca-ATPase specific activity of isolated sarcoplasmic reticulum was 60% increased in congestive cardiomyopathy (543 +/- 140 vs 873 +/- 108 nmol ATP hydrolyzed/min/mg membrane protein) although membrane yield was 20% decreased (0.79 +/- 0.09 vs 0.63 +/- 0.03 mg/g heart). The increased ATPase and decreased Ca-uptake activities in combination with the occurrence of 36% cardiac hypertrophy and 19% decreased body weights resulted in estimates of the relative energy cost to the animal for myocardial Ca transport being 5.5-fold increased with cardiomyopathy (20.5 vs 111 nmol ATP hydrolyzed per microM decrease of sarcoplasmic free Ca/kg body weight). These data indicate that congestive cardiomyopathy is associated with markedly increased permeability of sarcoplasmic reticulum to Ca and compensatorily increased Ca-ATPase activity. Accelerated energy consumption due to the increased energy cost of Ca transport and increased time of myocyte activation are predicted to predispose the myocardium to fatigue and irreversible failure.

Cardiac and muscle fatigue due to relative functional overload induced by excessive stimulation, hypersensitive excitation-contraction coupling, or diminished performance capacity correlates with sarcoplasmic reticulum failure

The development of muscle fatigue due to exhaustive exercise is associated with impaired sarcoplasmic reticulum (SR) Ca-transport activity. This study tested the hypothesis that SR failure is a consistent feature of cardiac and skeletal muscle fatigue owing to relative functional overload regardless of the method of induction: excessive stimulation, diminished performance capacity, or excessive excitation-contraction coupling. The Ca-transport activity was determined using three unique models of muscle fatigue: chronic and rapid ventricular pacing in dogs; metabolic inhibition caused by global cardiac ischemia in swine; and the hypermetabolic syndrome of porcine malignant hyperthermia (MH). Both pacing- and ischemia-induced fatigue resulted in reduction of SR Ca-transport ATPase activity: from 275 +/- 58 to 159 +/- 57 nmol.min-1.mg-1 (mU/mg) and from 577 +/- 82 to 177 +/- 133 mU/mg, respectively. Both pacing-induced fatigue and halothane-induced MH resulted in reduction of Ca-sequestration activity of muscle homogenates from 5.95 +/- 2.4 to 3.11 +/- 0.67 nM/s at 300 nM Ca and 38.7 +/- 10.5 to 16.3 +/- 8.0 nM/s at 1500 nM Ca, respectively (all p less than 0.01). The isolated SR Ca-ATPase activity correlated with Ca-sequestration activity of myocardial homogenates (r = 0.76; p less than 0.005). Different models were used to study the relationship of Ca-transport activity with relaxation function, degree of acidosis, and ionized Ca concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pharyngeal area measured by acoustic reflection technique while breathing room-air]

Although there have been many reports on the airway area measured by breathing 80% He-20% O2 (He-O2) using the acoustic reflection technique (ART), there have been no reports on that by breathing room-air (Air) because of the lack of accuracy in evaluating the trachea. When measuring with He-O2, accidental introduction of Air into the airway makes the measurement inaccurate. Moreover, it is a time-consuming method and is hardly applicable to dyspneic patients. Therefore, we tried to assess whether the airway area, especially the upper airway, can be measured while breathing Air. In order to compare the areas determined by the two methods, area-distance functions from the pharynx to the trachea were arbitrarily divided into 9 divisions at interval of 2.8 cm. Each of these divisions was respectively compared. We took averages of the pharyngeal, tracheal areas in 8 normal subjects. We found no significant difference between the oropharyngeal area measured by breathing Air and that measured by breathing He-O2, and found a significant correlation between them. There was a significant correlation between the hypopharyngeal areas when using the two methods. The average tracheal area by breathing Air is 4.96 +/- 0.50 cm2, which is 40% above that when measured using He-O2 (3.55 +/- 0.32 cm2). In contrast, the average pharyngeal area when breathing Air is 4.13 +/- 0.93 cm2, which overestimates that by breathing He-O2, namely 3.54 %/- 0.84 cm2 by only 17%. In conclusion, it is possible and useful to estimate the pharyngeal area by breathing Air.

Measurement of the refractive index and thermal refractive index coefficients of Nd:YAP crystal

The principal refractive indices of yttrium aluminate crystal doping with 1-wt.% neodymium (Nd:YAP) have been measured by a minimum deviation method for the wavelengths 0.5398, 0.6328, and 1.0795 microm in the temperature range of 289-435 K. The thermal refractive index coefficients have been obtained at these wavelengths, and they are all positive and slightly decrease with increased wavelength. The constants of the single term Sellmeier equation are also given for the 273-420 K temperature range. These constants are in linear relationship with temperature in the 4 x 10(-3) error range.

[The finite element analysis of the bicuspid and molar of mandible]

Recently, the finite element method has been adopted in the study of tooth structure as well as the stress distribution of dental prosthesis. In order to understand the loading state of the supporting tissues and the stress distribution of the teeth in various shapes under the pressure of loading, the author of this essay has applied the two-dimensional finite element method to the study of the stress distribution of the periodontal supporting tissues at the time when the second bicuspid and the second molar are vertically and obliquely loaded. Finally, the results of the quantitative analysis are obtained and a curve of the stress distribution of the teeth is also drawn up. The conclusion is as follows: 1. When the vertical loading is applied to the occlusal surface of the bicuspid and molar, the stress distribution of periodontal supporting tissues is uniform. 2. The stress concentration is on the marginal ridge and thedistal apex of bicuspid under the oblique loading. 3. When the oblique loading is applied to the occlusal surface of the molar, the stress concentration is only on the marginal ridge, and it is small.

Analysis of surface deposits on intrauterine contraceptive devices

Surface deposits on stainless steel contraceptive devices removed from the uterus after varying periods of insertion were examined and analyzed by means of scanning electron microscopy (SEM), X-ray energy dispersive analysis (XEDA), Augar electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and atomic absorption spectrophotometry for microquantitative analysis. The data obtained were compared with the data for copper-bearing IUDs (TCu200) obtained by the same method. The wire coils of stainless steel IUDs which had been in situ for 5 years showed no obvious changes, but copper wire coils showed varying degrees of erosion after the same period of time. Analysis clearly showed that the wire coils of both types of IUD were encrusted with deposits. Deposition began earlier on copper-bearing IUDs than on stainless steel IUDs (27 days and 3 months after insertion, respectively). This process began earlier than has previously been reported in the literature. The amount of deposit increased with duration of insertion, but there were large individual variations. The microanalysis showed that the principal component of the deposit on both types of IUD was calcium, which was present in the crystal form of calcium carbonate. The substances attaching to the crystals were similar to the nitrogenous organic compounds. We suggest that the mechanism regulating the deposited formation may be similar to that of calculus. The influence of these deposits on complications relating to IUD insertion, such as uterine bleeding and accidental pregnancy, is briefly discussed in this article. The subject should be studied in greater detail.

[Photodynamic therapy (PDT) of bladder cancer in the rat]

PDT of rat bladder cancer, induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) was studied. All animals were divided at random into three groups. Group 2 and 3 were treated by hematoporphyrin derivative (HPD)-laser PDT while group 1, without treatment, served as control. The results showed that the malignant lesions could be selectively and obviously destroyed, if the whole tumor area were sufficiently exposed to the laser irradiation. However, the normal bladder epithelium and muscle layer showed no histologic change. Similar reactions were found in papilloma of bladder which was considered as precancerous lesion. Thus, PDT may be beneficial to cancer prevention. Its role in prevention and treatment of bladder cancer should be further studied experimentally and clinically.

A randomized comparative clinical evaluation of the Steel Ring, the VCu200 and the TCu220c IUDs

A randomized comparative clinical study of the Steel Ring, VCu200 and TCu220c IUDs was carried out in Beijing. Six-hundred subjects were recruited and each group of 200 was inserted with one of the three devices. The TCu220c and the VCu200 had statistically significantly lower pregnancy and expulsion rates at one and two years of use than the Steel Ring. However, the Steel Ring consistently had the lowest rate of removal for pain and/or bleeding. At two years, the early differences of use-related discontinuation and continuation between the higher rates of the Steel Ring and the lower rates of the VCu200 and TCu220c were significantly reduced. There were no statistically significant differences of net event rates between VCu200 and TCu220c.

The biological effects of photodynamic therapy on normal skin in mice--I. A light microscopic study

A light microscopic investigation of the biological effects of photodynamic therapy using hematoporphyrin derivative and red light irradiation has been carried out. HpD alone, even used at a dose of 50 mg/kg, did not cause histologically discernible changes. The irradiation alone used in this experiment caused only slight or moderate dilatation and congestion of blood vessels, which disappeared completely within several hours after light exposure. In the PDT treated mouse ears severe degeneration and necrosis of skin tissue occurred within 1-2 days. The importance of adequate drug and light doses and proper interval chosen for obtaining best therapeutic effects and protection of surrounding normal tissues was pointed out. The possible mechanism of the PDT action in vivo was briefly discussed.

The biological effects of photodynamic therapy on normal skin in mice--II. An electron microscopic study

In the present study it has been demonstrated that the ultrastructural changes in mouse ear skin after PDT action occurred much more distinct and earlier than those observed in the histological study. Various types of cells in the skin respond to the photodynamic action differently. The endothelial cells, fibroblasts and nerve fibers are most sensitive. In contrast, the keratinocytes and chondrocytes often remain rather well preserved after PDT treatment. The possible mechanism of PDT action was briefly discussed.

Influence of vitamin deficiency and level of dietary protein on the incidence of leg problems in broiler chicks

Diets containing either 22 or 30% protein were supplemented with a vitamin mix where one of 11 added vitamins were singly eliminated from the mix. Male, day-old broilers were fed these diets to 3 weeks of age, and weight gains, feed utilization, and leg problems were recorded. In general, the higher protein diet did not result in a greater incidence of leg problems; however, it did alter performance of several of the vitamin-deficient diets as compared to the lower protein diet. Of the 11 vitamins studied only nonsupplementation of riboflavin markedly reduced weight gain and feed utilization during the 3-week feeding period. However, deletions of vitamin D3 and niacin also resulted in reduced performance. Riboflavin deficiency resulted in paralysis in a high percentage of the birds while the niacin-deficient diet gave a high percentage of birds with deformed legs and problems of mobility. The results demonstrate that a high incidence of leg problems may be present in a flock with little or no signs of reduced gain or feed utilization. The data suggest that under practical conditions the elimination of a particular vitamin from a diet for a short period of time would probably have a negligible effect on performance.

Alterations in levels of thyrotrophin releasing hormone and rates of hormone degradation in hypothalamic tissue of the developing rat

Developmental changes in levels of hypothalamic thyrotrophin releasing hormone (TRH) and the role that hypothalamic degrading enzymes may play in these alterations were investigated. Levels of TRH in male and female fetal rats and in male neonatal rats were measured by radioimmunoassay. The hormone content of the hypothalamus was shown to increase from less than 1 ng at 1--4 days of age to approximately 10 ng at 20 days of age. Thereafter, the content of TRH declined to the adult level of about 5 ng. The ability of fractionated hypothalamic homogenates to degrade TRH was measured over the same time. The 27 000 g supernatant fraction contained a degrading activity that yielded only radiolabelled deamido-TRH upon incubation with [L-proline 2,3-3H]TRH. The corresponding particulate fraction contained at least two distinct TRH degrading activities as determined by the number of metabolites present. Changes in rates of degradation were not large enough to account for the differences observed in levels of TRH.

A flow calorimetric method of determining electron beam energy

The construction of an adiabatic flow calorimeter using water as the working substance is described. It is shown that at high dose rates the heat defect due to chemical reactions in water is small (of the order of 0-3%) and that under high dose rate conditions flow calorimetry can be used as a method of measuring the energy of high intensity electron beams. Measurements made with a 15 MeV linear accelerator are reported and compared with magnetic measurements.