Calcium antagonists and calmodulin inhibitors block cytokinin-induced bud formation in Funaria

The plant hormone cytokinin stimulates nuclear migration followed by an asymmetric cell division in target cells of the protonema of the moss Funaria hygrometrica, leading to bud formation. The role of calcium in this developmental event was investigated by examining the effects of various calcium antagonists on the cytokinin-induced division. Calcium-free medium (buffered with EGTA), the extracellular Ca2+ antagonist La3+ (lanthanum), and the Ca2+ channel inhibitors D 600 and verapamil all block bud formation. These inhibitions are partially reversed by washing the cells or by raising the extracellular [Ca2+]. The Ca2+ ionophore A23187 partially reversed the effects of D 600 and verapamil. Bud formation is also inhibited by the intracellular Ca2+ antagonist TMB-8 (8-diethylamino)octyl 3,4,5-trimethoxybenzoate HCl), and this inhibition is partially reversed by washing or raising the extracellular [Ca2+]. The cross walls of both the filaments and bud initial cells formed during TMB-8 exposure exhibit a distorted morphology. High concentrations of TMB-8 block nuclear migration. The calmodulin inhibitor trifluoperazine stops cytokinin-induced budding more effectively than the related compound chlorpromazine. Low concentrations of these two compounds do not affect nuclear migration; however, the target cell does not enter mitosis. These results support the hypothesis that a rise in intracellular calcium mediates cytokinin-induced bud formation in Funaria. It is concluded that the proposed cytokinin-induced rise in intracellular calcium may be effected in part by the activation of calmodulin. The essential source of Ca2+ appears to be extracellular, because blocking Ca2+ uptake with Ca2+ transport inhibitors can block both nuclear migration and subsequent division.

Comparison of intrauterine and subcutaneous sites of estrogen injection for luteal maintenance in swine

Intrauterine and subcutaneous sites for estradiol benzoate (EB) injection were compared in 30 gilts to test their relative effectiveness for estrogen-induced maintenance of corpora lutea. Vehicle or EB was injected on d 10 through 14 of the estrous cycle and corpora lutea that were maintained through d 24 were regressed subsequently by exogenous prostaglandin F2 alpha (10 mg). Cycle length (days) was not altered in either subcutaneous (18.6 +/- .5) or intrauterine (19.8 +/- .8) control groups. Gilts receiving 10 mg EB/d sc had longer (P less than .05) cycles (28.6 +/- 2 d) than gilts treated with 100 micrograms EB at either the sc (24.2 +/- 1 d) or intrauterine sites (23.3 +/- 1.3 d). The latter two cycle lengths were longer (P less than .05) than control cycles, but not different from each other. Before d 24, progesterone concentrations (ng/ml serum) were greater (P less than .01) in EB-treated gilts (25.1 +/- 2.0) than in controls (13.0 +/- 2.7). Progesterone concentration patterns were similar between gilts treated at intrauterine or sc sites. Thus, EB-induced maintenance of corpora lutea was not enhanced by direct injection into the uterine lumen.

Prevalence and relation to underground exposure of radiological irregular opacities in South Wales coal workers with pneumoconiosis

A total of 124 coal workers and ex-coal workers receiving disability benefit for coal worker's pneumoconiosis and routinely reattending the Cardiff Pneumoconiosis Medical Panel during a 10-week period were studied. Those with complicated pneumoconiosis were excluded. Their current chest radiographs and their chest radiographs at the time of certification were read in random order by three readers using the 1980 ILO Classification of Radiographs. An irregularity score was derived from the readings. The x-ray findings were examined for changes since certification and for relationships with age, smoking, and underground coal work exposure. One-fifth of the current radiographs showed mainly irregular opacities, whereas nearly all of those from the time of certification showed mainly irregular opacities, whereas nearly all of those from the time of certification showed mainly rounded opacities. Irregular opacities were related to age, smoking, and underground exposure. The exposure effect remained after excluding the older men. The findings suggest that radiological irregular opacities, and their associated pathology and lung function changes, commonly develop in coal workers with pneumoconiosis and should be considered part of the condition.

Calcium Ionophore A23187 Stimulates Cytokinin-Like Mitosis inFunaria

The plant hormone cytokinin stimulates asymmetrical division in target cells of the protonema of the mossFunaria hygrometrica,leading to bud formation. The initial division can be induced in the absence of cytokinin by the calcium ionophore A23187 in medium containing calcium. These findings suggest that increases in the concentration of intracellular calcium are essential to bud initiation. Therefore mitotic regulation by cytokinin may be due, at least in part, to the modulation of intracellular calcium ion concentration.

Localization of membrane-associated calcium following cytokinin treatment in Funaria using chlorotetracycline

We have investigated the changes in membrane-associated calcium that occur during cytokinin induced bud formation in Funaria hygrometrica Hedw. using the fluorescent Ca(2+)-chelate probe chlorotetracycline (CTC). In the target caulonema cells a localization of CTC fluorescent material becomes evident at the presumptive bud site 12 h after cytokinin treatment. By the time of the initial asymmetric division this region is four times as fluorescent as the entire caulonema cell. Bright CTC fluorescence remains localized in the dividing cells of the bud. To relate the changes in CTC fluorescence to changes in Ca(2+) as opposed to membrane-density changes we employed the general membrane marker N-phenyl-1-naphthylamine (NPN). NPN fluorescence increases only 1.5 times in the initial bud cell. We conclude that the relative amount of Ca(2+) per quantity of membrane increases in this localized area and is maintained throughout bud formation. We suggest that these increases in membrane-associated Ca(2+) indicate a localized rise in intracellular free Ca(2+) concentration brought about by cytokinin action.

Optical fiber profiles using the refracted near-field technique: a comparison with other methods

Multimode fiber profiles by the refracted near-field method (RNF) agree to within +/-0.5% with profiles obtained by the highly accurate interferometric slab technique in regions of adequate resolution of the latter. Nineteen multimode fiber profiles by the RNF and transverse interferometric methods differ in Delta and alpha on the average by 4% and 3%, respectively. The precision of a refractive-index determination by the RNF technique is 4 x 10(-5). A rapid method of calibrating the profiles by measuring the liquid temperature is presented, and the effect of foreign matter on the fiber face is discussed.

Randomised controlled trial of rehabilitation in chronic respiratory disability

A randomised controlled study of the effects of exercise training in 39 patients with chronic respiratory disability was performed. Exercise training began with six weeks in a rehabilitation centre and was continued at home. The original control group attended the rehabilitation centre after the controlled part of the study. The treated group experienced subjective benefit from rehabilitation. The 12-minute walking distance increased on average from 523 m to 643 m in the treatment group and from 564 m to 607 m in the control group. The treatment effect of 77 m (SE 33 m) was significant at the 5% level. Treadmill exercise performance changed little and resting lung function was unaltered after rehabilitation. The treatment group maintained most of their improvement seven months later and the original control subjects improved after their rehabilitation. The study confirms the beneficial effects of exercise training in the chronically breathless and it suggests that the 12-minute walking distance is a useful index of changes in everyday exercise tolerance.

Radiographic heart volume, stroke volume and exercise cardiac frequency: relationship to body composition and other factors in healthy adult males

Amongst 288 healthy male workers in heavy industry the radiographic heart volume was related to the fat-free mass and the percentage body fat which between them explained 27% of the variance. Exercise was performed on a treadmill using a belt speed of 80 m.min-1 (3 mph) and an incline which was increased progressively to 14% when the oxygen uptake was on average 61% of the maximum for these subjects. The exercise cardiac output was related to the uptake of oxygen, the fat-free mass and the ambient temperature; these factors accounted for 52% of the variance. The exercise stroke volume was related to the heart volume, the fat-free mass, the thigh muscle width, the ambient temperature, the Harvard Pack Index and other measurements which between them accounted for 42% of the variance. The exercise cardiac frequency was correlated negatively with the heart volume, the fat-free mass, the age and the Harvard Pack Index. The variates between them described 41% of the variance. The findings provide reference values for heart volume, stroke and exercise cardiac frequency in similar subjects.

Interpretation of lung function tests in the sickle-cell haemoglobinopathies

Prediction equations have been evolved for the assessment of vital capacity, total lung capacity, and the single breath carbon monoxide transfer factor in haemoglobin SS and haemoglobin SC disease. These relationships take account of the growth disorder and anaemia in the sickle-cell states. The results suggest that, in the clinically stable state, any effects of alveolar capillary sickling and haemoconcentration and any altered reactivity of haemoglobins S and C with the test gas are of no significance for clinical respiratory physiology. Sex differences in lung function appear independent of haemoglobin type.

Nondestructive interferometric measurement of the delta and alpha of clad optical fibers

It is shown that interferograms generated by passing light perpendicular to the axis of a fiber can be used to obtain the maximum refractive index difference and the index profile shape to better than +/-10% accuracy in regions of the core where alpha is constant. This technique avoids the time consuming sample preparation required for the slab method, the propagation problems associated with the near-field technique, and the surface quality problem associated with the reflection technique.

Lung function of healthy boys and girls in Jamaica in relation to ethnic composition, test exercise performance, and habitual physical activity

Miller, G. J., Saunders, M. J., Gilson, R. J. C., and Ashcroft, M. T. (1977).Thorax, 32, 486-496. Lung function of healthy boys and girls in Jamaica in relation to ethnic composition, test exercise performance, and habitual physical activity. The relationships of forced expiratory volume and forced vital capacity on height, age, sex, area of residence, and ethnic composition were assessed in 622 children in Jamaica. Rural children in hill-farming communities were judged to have a higher habitual physical activity than urban children. Allowing for differences in body size, forced vital capacity averaged 3% greater in rural children than in urban children, 7% less in girls than in boys, and 16% greater in children of European origin than in children of African descent.

Lung volumes, indices of gas transfer, and submaximal-exercise responses were measured in a subgroup of 108 children of African descent believed to be of common genetic stock. Total lung capacity and vital capacity averaged respectively 6% greater and 7% greater in rural than in urban children of equal height but residual volume and transfer factor did not differ significantly between localities.

Rural children had a lower average cardiac frequency during test exercise than did urban children. Sex differences and locality differences in vital capacity and total lung capacity disappeared when allowance was made for standardised exercise cardiac frequency. At standard body size and age transfer factor increased with decreasing cardiac frequency for standard work.

The results suggest an harmonious development of the cardiac and respiratory components of the oxygen transport system, consonant with the demand for muscular work. Increased habitual physical activity and improved exercise performance appear to be associated with increases in vital capacity, total lung capacity, and transfer factor.

The cross-linking of rabbit skeletal muscle sarcoplasmic reticulum protein

Sarcoplasmic reticulum proteins have been cross-linked in situ with two reagents, the disulphide-bridged bifunctional imido ester, dimethyl-3,3'-dithiobispropionimidate dihydrochloride and the mild oxidant cupric phenanthroline. Analysis of proteins so cross-linked by electrophoresis on agarose/acrylamide gels reveals that a series of new polypeptides, up to a molecular weight of 900 000, are formed. These have molecular weights which are multiples of 100 000. Further analysis of samples by electrophoresis in a second dimensions containing a reducing agent revealed the monomeric polypeptides from which the cross-linked polypeptides were formed. With dimethyl 3,3'-dithiobispropionimidate dihydrochloride homopolymers of the Ca2+-stimulated ATPase, calsequestrin and/or calcium binding protein were formed. With cupric phenanthroline only the Ca2+-stimulated ATPase was involved in polymer formation. It has been confirmed on another gel system that these two proteins which are involved in Ca2+ binding are not cross-linked intermolecularly with this latter reagent. We conclude that the 100 000 dalton Ca2+-stimulated ATPase polypeptides are within 2 A of each other in the membrane while calsequestrin and/or calcium binding protein are within 11 A of each other. Although there appears to be no limit to the extent of cross-linking of any of these polypeptides there is not indication of heteropolymer associations between them.

Lung function of healthy young men in India: contributory roles of genetic and environmental factors

The forced expiratory volume and vital capacity, the total lung capacity and sub-divisions and the lung transfer factor for carbon monoxide and its sub-divisions have been measured on 122 young men living near Delhi, including Servicemen from Gurkha, Rajput and south Indian regiments and civilians mainly from north India. The findings, standardized for age and stature and in the case of the transfer factor the smoking habits, the haemoglobin concentration and the tension of oxygen in the alveolar capillaries, have been compared with those for European and New Guinea men studied by similar methods and with data reported in the literature for other inhabitants of the Indian sub-continent. The lung function of the present Gurkha highlanders is superior to that of the Indian lowlanders and resembles that of both New Guinea highlanders living at an altitude of approximately 1800 m and men from Bhutan (altitude 3100 m). The Rajputs and other north Indians have slightly larger lungs than the men from south India; the lung function of the latter subjects resembles that of the New Guinea coastal dwellers. All these lowland subjects have lungs which are materially smaller than those of Europeans. The observed differences may be explained in terms of a genetic factor which contributes to the relatively large lung of people of European descent and an environmental factor, probably related to physical activity during childhood, which contributes to the superior lung function of hill people. The possible survival value in an inhospitable environment of large and permeable lungs may also have contributed to the difference, but the magnitude of this effect is probably small.

Lung function in coastal and highland New Guineans--comparison with Europeans

The lung volumes, ventilatory capacity, and transfer factor of young adult male and female New Guineans living at sea level, after standardization for age, height, and, in the case of transfer factor, the haemoglobin concentration, resemble those of people of Indian and West African descent. The inspiratory capacity and expiratory reserve volume are smaller than for comparable Europeans. The highland New Guineans have a larger total lung capacity and transfer factor than the coastal dwellers due mainly to a larger inspiratory capacity. Compared with representative Europeans, the highlanders have a similar total lung capacity but larger transfer factor. The exceptional lung function of the New Guinea highlanders is not closely related to altitude and is probably determined at least in part by their present mode of life entailing a high level of habitual activity. This factor needs to be taken into account when considering `normal values'.

Iron-deficiency anaemia: its effect on transfer factor for the lung (diffusiong capacity) and ventilation and cardiac frequency during sub-maximal exercise

1. Measurements of transfer factor and sub-maximal exercise ventilation and cardiac frequency have been made on twenty women with iron-deficiency anaemia (Hb 8–9 g/100 ml) before and after ‘treatment’ with iron or placebo tablets and on control subjects.

2. The exercise ventilation, cardiac frequency and oxygen uptake were independent of haemoglobin concentration but the transfer factor was lower in the test than in control subjects and was increased by iron but not by placebo treatment. The results support the validity of the reaction-rate data for carbon monoxide with oxyhaemoglobin of Roughton & Forster (1957) despite evidence to the contrary from other studies.

3. In interpretation of sub-maximal exercise ventilation and cardiac frequency in iron-deficiency anaemia no allowance need be made for variation in haemoglobin concentration in the range 8–15 g/100 ml. For transfer factor a correction should be made by using a variant of the relationship of Roughton & Forster (1957).

A 60 percent oxygen supply for medical use

A supply of 60% oxygen with 40% nitrogen should be acceptable for most clinical purposes, since usually only low dosages of oxygen are required. The gas may be provided by means of an oxygen concentrator (Rimer-Birlec), which is a compact, transportable, electrically operated apparatus capable of providing 28 l./min. (1 cu. ft./min.) of 60% oxygen from a source of compressed air. The biological effect of the gas from the device is the same as that of 60% oxygen from a conventional source. Measurements of inspired oxygen concentration show that the 60% oxygen may be used with present-day oxygen masks to provide inspired oxygen concentrations in the range 25 to 40%; for higher inspired concentrations alternative equipment is likely to be required. The concentrator appears to be a practical source of oxygen for expeditions and out-of-the-way places. It may provide an economical supply for a ward block, and with further development should be a convenient source of 30% oxygen for domiciliary use.

Preparation of Submicroscopic Spider Threads for Particle Studies

Many small spiders produce threads of different diameters, some of which are submicroscopic. When the threads are subjected to an environment of tobacco smoke and then examined microscopically, the invisible threads are manifested as particles in a line with no visible connection. These threads are used to support microscopic water droplets in single-particle scattering experiments.