Influence of prior and visual information on eye movements in amblyopic children

This study analyzed the characteristics of pursuit and assessed the influence of prior and visual information on eye velocity and saccades in amblyopic and control children, in comparison to adults. Eye movements of 41 children (21 amblyopes and 20 controls) were compared to eye movements of 55 adults (18 amblyopes and 37 controls). Participants were asked to pursue a target moving at a constant velocity. The target was either a ‘standard’ target, with a uniform color intensity, or a ‘noisy’ target, with blurry edges, to mimic the blurriness of an amblyopic eye. Analysis of pursuit patterns showed that the onset was delayed, and the gain was decreased in control children with a noisy target in comparison to amblyopic or control children with a standard target. Furthermore, a significant effect of prior and visual information on pursuit velocity and saccades was found across all participants. Moreover, the modulation of the effect of visual information on the pursuit velocity by group, that is amblyopes or controls with a standard target, and controls with a noisy target, was more limited in children. In other words, the effect of visual information was higher in control adults with a standard target compared to control children with the same target. However, in the case of a blurry target, either in control participants with a noisy target or in amblyopic participants with a standard target, the effect of visual information was larger in children.

     

Measles immunisation in children with allergy to egg.

OBJECTIVE--To examine the occurrence of adverse reactions to measles vaccine given as a single dose to children with egg allergy, and to determine if the administration of single dose to children with a positive result in an intradermal skin prick test with the vaccine is associated with adverse reactions. DESIGN--Review of results of immunisation and prospective study of 96 consecutively presenting children given intradermal skin testing with the vaccine. SETTING--Children''s allergy centre. SUBJECTS--410 children sensitive to egg referred to the allergy unit for advice about measles immunisation. MAIN OUTCOME MEASURES--Nature and severity of reactions associated with the administration of measles vaccine. RESULTS--All children had a positive result in a skin prick test with egg white, and five had a positive result in a skin prick test with vaccine. Of 96 consecutive children, 46 had a positive result in an intradermal test with vaccine. After immunisation with a full dose (0.5 ml) of vaccine adverse reactions were associated with a mild reaction in four children, none of whom required treatment. Only one of the 46 children with a positive result in an intradermal vaccine skin test had a reaction associated with vaccine administration. None of the children with a positive result in a skin prick test with measles vaccine reacted to the vaccine. The rate of minor reactions to the vaccine not requiring treatment was 0.98% (95% confidence interval 0.27% to 2.48%) and serious reactions requiring treatment was 0% (0% to 0.9%). CONCLUSION--Children with IgE mediated allergic reactions to egg protein should be investigated and managed by practitioners with special knowledge in this subject. Measles immunisation should be performed in a setting where any adverse reactions can be dealt with appropriately. Skin tests and measles vaccine and desensitisation are not necessary.     

Somatostatin release in the hippocampus in the kindling model of epilepsy: a microdialysis study

Somatostatin biosynthesis in the hippocampus is activated during and following kindling epileptogenesis. The aim of this study was to investigate whether this phenomenon is associated with enhanced somatostatin release in vivo. Experiments have been run in awake, freely moving rats, implanted with a bipolar electrode in the right amygdala (for kindling stimulation), and with a recording electrode and a microdialysis probe in the left hippocampus. Basal somatostatin-like immunoreactivity (-LI) release was significantly greater in kindled than naive rats. In naive rats, a 2-min perfusion with 100 mM K(+) did not affect behavior and EEG recordings and nonsignificantly increased somatostatin-LI release; a 10-min K(+) perfusion evoked numerous wet dog shakes, electrical seizures (class 0; latency congruent with 8 min, duration congruent with 8 min), and somatostatin-LI release ( congruent with 350% of basal); and a single kindling after-discharge (4 +/- 3-s duration in the hippocampus) also evoked somatostatin-LI release ( congruent with 200% of basal). In kindled rats, a 2-min 100 mM K(+) perfusion evoked hippocampal discharges in three of seven animals (latency congruent with 2 min, mean duration congruent with 1.5 min) and increased somatostatin-LI release ( congruent with 250% of basal); a 10-min K(+) perfusion evoked behavioral seizures (class 1 to 5, latency congruent with 4 min, mean duration congruent with 12 min) with numerous wet dog shakes and robust somatostatin-LI release ( congruent with 350% of basal); and a kindling stimulation evoked generalized seizures (class 4 or 5, 77 +/- 15-s duration in the hippocampus) with remarkable somatostatin-LI release ( congruent with 300% of basal). These data demonstrate that hippocampal somatostatin release is increased in the kindling model in vivo.     

Excitation of waves in an inhomogeneous plasma

The evolution of initial perturbations in a spatially inhomogeneous cold electron plasma in the absence of an external magnetic field is considered. The excitation of both continuous-spectrum bulk plasma waves and surface plasma waves with a discrete frequency spectrum is investigated. Analytic solutions are obtained in the long-wavelength limit, and the excitation of waves of arbitrary length is analyzed numerically. The local, integral, and spatial spectra are calculated, as well as the field structures and dispersion properties of waves in waveguides filled nonuniformly with a plasma. It is shown that, in a plasma with a smooth boundary, there also exist surface waves with a discrete spectrum (although with somewhat different properties as compared to those in a plasma with a sharp boundary), which are excited together with continuous-spectrum bulk waves during the evolution of the initial perturbation.     

基于小波分析的大豆叶绿素a含量高光谱反演模型

 2003和2004年分别在长春市良种场和中国科学院海伦黑土生态实验站实测了大田耕作与水肥耦合作用下大豆（Glycine max）冠层高光谱反射率 与叶绿素a含量数据,对光谱反射率、微分光谱与叶绿素a含量进行了相关分析;采用归一化植被指数(Normalized diffe rence vegetation index, NDVI)、土壤调和植被指数(Soil-adjusted vegetation index, SAVI)、再归一植被指数(Renormalized difference vegetation index, RDVI)、第二修正比值植被指数(Modified second ratio index, MSRI)等建立了大豆叶绿素a反演模型;应用小波分析对采集的光谱反 射率数据进行了能量系数提取,并以小波能量系数作为自变量进行了单变量与多变量回归分析,对大豆叶绿素a进行了估算。研究结果表明,大 豆叶绿素a 与可见光光谱反射率相关性较好,并在红光波段取得最大值(R²>0.70),但在红边处,微分光谱与大豆叶绿素a的相关性较反射率好 得多,在其它波段则相反;由NDVI、SAVI、RDVI、MSRI等植被指数建立的估算模型可以提高大豆叶绿素a的估算精度（R²>0.75）;小波能量系 数回归模型可以进一步提高大豆叶绿素a含量的估算水平,以一个特定小波能量系数作为自变量的回归模型,大豆叶绿素a回归决定系数R²高达 0.78;多变量回归分析结果表明,大豆叶绿素a实测值与预测值的线性回归决定系数R²均高达0.85。以上结果表明, 小波分析可以对高光谱进 行特征变量提取,并可在一定程度上提高大豆生理参数反演精度。     

Effects of Feeding a Histidine-excess Diet and Subsequent Starvation on Liver and Muscle Glycogen,and on Serum Glucose

The effects of feeding with a histidine-excess diet and subsequent starvation on liver and muscle glycogen, and on serum glucose were investigated in young and adult rats.

Feeding with a histidine-excess diet resulted in the accumulation of liver glycogen in both young and adult rats. The hepatic glycogen continued to decrease during starvation, and the liver became almost totally depleted of glycogen after starvation for 48 hr. Glycogen in the liver of young rats starved for 24 hr after previous feeding with a histidine-excess diet was significantly higher than that of young rats starved for 24 hr after previous feeding with a basal diet.

Muscle glycogen after feeding and subsequent starvation was not affected by the types of diets fed previously, muscle glycogen during starvation showing a slight decrease in young rats and a slight increase in adult rats.

Feeding with a histidine-excess diet caused a significant decrease of serum glucose in young rats, but not in adult rats. Serum glucose in young rats was markedly reduced by starvation after previous feeding with a basal diet, but not after previous feeding with a histidine-excess diet. In adult rats, there were no changes in serum glucose between rats starved after feeding with either a basal diet or a histidine-excess diet, and serum glucose was decreased slightly by starvation after feeding with the test diets.

The overall results indicate that the maintenance of serum glucose in young rate even during starvation after previous feeding with a histidine-excess diet might be partially concerned with the export of glucose from the accumulated glycogen in the liver due to the diet.     

Comparative toxicity of high doses of vastatins currently used by clinicians, in CD-1 male mice fed with a hypercholesterolemic diet.

The CD-1 male-mouse model was employed to evaluate comparatively the toxicity of four vastatins (VTS) currently used in clinical medicine: lovastatin (LVT), simvastatin (SVT), pravastatin (PVT) and fluvastatin (FVT). Each vastatin was used orally in doses of 500 mg/Kg body weight/day, in animals with a hypercholesterolemic diet (HD) 5 days, or with a control diet (CD) 30 days. The association of high doses of VTS + HD produced a significant increase in liver weight and liver weight to body weight ratio in animals with SVT and FVT. Cholesterol (Chol) and triacylglycerols (TAG) in the liver increased significantly with FVT but not with the other VTS; Chol increased and TAG decreased in serum very significantly with FVT and SVT. The serum aminotransferases increased quite significantly with FVT but not with other VTS. In the experiment with high doses of VTS + CD, the animals receiving SVT or FVT showed a moderate loss of body weight. Liver weight and liver weight to body weight ratios were similar among all groups. Liver Chol showed a significant decrease with all VTS. Serum Chol decreased moderately with LVT and FVT. TAG in serum and liver showed a moderate decrease with all VTS. The serum aminotransferases were not modified by any vastatin. Our results indicate that high doses of VTS in male mice with a hypercholesterolemic diet result in a decreasing toxicity as follows: FVT>SVT>LVT>PVT.     

Tumor growth inhibition by sonodynamic therapy using a novel sonosensitizer

Sonodynamic therapy (SDT) with low-intensity ultrasound combined with a sonosensitizer may be a promising approach to cancer therapy. Use of ultrasound has the advantage of being noninvasive, with deep-penetration properties, and convenient because of the low or no sensitivity of sonosensitizers to light. In this study, SDT with a novel sonosensitizer (a porphyrin derivative) was evaluated in vitro and in vivo. Ultrasound irradiation with a sonosensitizer elicited potent sonotoxicity in vitro without the danger of phototoxicity. The sonotoxic effect was mediated by reactive oxygen species (ROS) and was reduced by ROS scavengers. Cell membrane lipid peroxidation increased significantly just after ultrasound irradiation with a sonosensitizer, but there was no increase in apoptosis. In an in vivo mouse xenograft model, SDT with a sonosensitizer markedly inhibited tumor cell growth. The skin hypersensitivity after light exposure was not observed in a sonosensitizer-treatment group, consistent with the in vitro findings. These results suggest that ROS generated by SDT with a sensitizer can damage tumor cells, resulting in necrosis and prevention of tumor growth. This noninvasive treatment with no adverse effects such as skin sensitivity is therefore promising for therapy of cancers located deep within patients.     

X-ray-induced mutation spectra of different germ-cell stages of Drosophila males with a double marked Y-chromosome and either a normal X-or a ring-X-chromosome (author's transl)

Different germ-cell stages of Drosophila males with a double marked Y-chromosome and either a normal X- or a ring-X chromosome were irradiated with X-rays, inducing the following aberrations: chromosome loss, chromosome gain (XYX-females), partial Y loss and isochromosomes of the Y-chromosome.Doses of 520 rad in spermatocytes and spermatids and 2600 rad in sperm, produced the same effect in these stages with regard to the chromosome loss in the males with a normal X, and the following results were obtained: (a) The partial Y loss in postmeiotic stages is small in comparison with spermatocytes in both stocks. This could mean that in spermatocytes this aberration is determined by exchange processes which can only be induced and/or detected in premeiotic stages. (b) In spermatocytes and mature sperm of males with a ring-X chromosome, the chromosome loss was 2.9 times greater than in those with a normal X. In spermatids of the males with a ring-X the rate of loss was only 1.5 times greater. In spermatocytes of either males with a ring-X or a normal X a similar high rate of isochromosomes could be induced. However, in spermatids and mature sperm the rate of induction of isochromosomes was found to be very small. These results seem to indicate that in mature sperm the rejoining of breaks in the Y-chromosome takes place before, and in the X-chromosome usually after the replication. If in post-meiotic stages of Drosophila the X- and Y-chromosomes existed as chromatid-like subunits then in spermatids these should behave as a structural unit.In sperm we were able to induce similar frequencies of individuals with a single isochromosome type in all body cells as of individuals with two types of isochromosomes (isochromosome mosaics). This result seems to indicate that after irradiation of sperm one of the first two division nuclei is lethal in an proportion of the zygotes.     

HLA-DR2, [HLA-B7, SC31, DR2], and [HLA-B8, SC01, DR3] haplotypes distinguish subjects with asthma from those with rhinitis only in ragweed pollen allergy.

MHC haplotypes were determined for 52 patients with ragweed pollen allergy, with and without asthma, and 27 non-atopic controls. Total IgE levels were unimodally distributed in all study groups and were higher in atopic patients in general compared with non-atopics. There was no difference in total IgE levels in patients with rhinitis only compared with those with rhinitis and asthma. IgE anti-Amb a V was detected (after subtraction of values representing the means + 2 SD of the non-atopics) in 9 of 20 asthmatics but only 3 of 32 patients with only rhinitis and was thus associated with asthma. Mean anti-Amb a V was much higher in the antibody-positive asthmatics (1710 U/ml) than in the positive patients with rhinitis only (469 U/ml). The extended MHC haplotype [HLA-B7, SC31, DR2] and its possible DR-containing fragment (SC31, DR2), were found almost exclusively among the patients with IgE anti-Amb a V and were significantly elevated in patients with asthma. DR2 in general, but not DR2 without SC31, was significantly increased in frequency in patients with anti-Amb a V. In contrast, the extended haplotype [HLA-B8, SC01, DR3] and DR3 in general were increased among patients with rhinitis only and patients without IgE anti-Amb a V compared with general controls. Thus, [HLA-B8, SC01, DR3] and DR3 appear to be "protective" for the production of this antibody and the occurrence of asthma. The findings are consistent with an MHC-linked gene or genes on [HLA-B7, SC31, DR2] (but not necessarily DR2, Dw2, or DQw6 in general) controlling the IgE immune response to Amb a V and associated with asthma in ragweed pollen-sensitive subjects. In patients with rhinitis alone and generally undetectable levels of IgE anti-Amb a V, the increase in [HLA-B8, SC01, DR3] and DR3 may mark a response to an as yet unidentified Ag associated with ragweed allergy and rhinitis only.     

Twin pregnancy with complete hydatidiform mole and coexisting fetus following ovulation induction with a non-prescribed clomiphene citrate regimen: a case report

Introduction

Until now, studies on paracetamol given intravenously have mainly been performed with the pro-drug propacetamol or with paracetamol in preterm babies above 32 weeks of gestation. Studies in these babies indicate that intravenous paracetamol is tolerated well, however studies on the efficacy of intravenous paracetamol are lacking. There are no pharmacokinetic data on the administration of multiple doses of paracetamol in preterm babies with a gestational age below 32 weeks.

Case presentation

We present a case series of nine Caucasian preterm babies, six boys and three girls, with a mean gestational age of 28.6 weeks (range 25.9 to 31.6 weeks). Case one, a girl with a gestational age of 25 weeks and six days, presented with necrotizing enterocolitis. In the second case, a female baby with a gestational age of 26 weeks and two days presented with hematoma. In case three, a female baby with a gestation of 26 weeks and one day developed intraventricular hemorrhage. In case four, a male baby with a gestational age of 31 weeks and four days presented with pain after vacuum delivery. Case five, a female baby born after a gestation of 29 weeks and six days presented with hematoma. In case six, a male baby with a gestation of 30 weeks and six days presented with hematoma. In case seven, a male baby, born with a gestational age of 30 weeks and six days, presented with caput succedaneum and hematoma. In case eight, a male baby, born after a gestation of 28 weeks and four days, developed abdominal distention. Case nine, a female baby, born with a gestational age of 27 weeks and three days presented with hematoma. These babies were treated with intravenous paracetamol 15 mg/kg every six hours. Serum concentrations and aspartate transaminase were determined after prolonged administration. Pain scores were assessed using the Premature Infant Pain Profile.

Conclusion

Paracetamol serum concentrations ranged from 8 to 64 mg/L after eight to 12 doses of intravenous paracetamol. Adequate analgesia was obtained in seven babies. During paracetamol therapy the median serum level of aspartate transaminase was 20 U/L (range 12 to 186 U/L). This case series indicates that prolonged intravenous administration of paracetamol in preterm babies with a gestational age of less than 32 weeks is tolerated well in the first days after birth. However, in the absence of proper pharmacokinetic data in this age group we cannot advocate the use of paracetamol intravenously.     

Aldosterone and renin in essential hypertension.

A review of some recent laboratory findings indicates definite disturbances in aldosterone metabolism and regulation in patients with mild essential hypertension: (a) a significant mean increase in plasma aldosterone concentration in patients with mild and stable essential hypertension, in contrast to the absence of any difference in patients with labile borderline essential hypertension when in a normotensive phase, compared with control subjects; and (b) a significant mean decrease in metabolic clearance rate of aldosterone, associated with a 12% decrease in hepatic blood flow and an increased binding of aldosterone to a transcortin-like plasma globulin. The secretion rate of 18-hydroxy-11-deoxycorticosterone is above the upper range of normal in 60% of patients with mild, uncomplicated essential hypertension. The incidence of low-renin hypertension, when age and race are taken into account, is much lower than previously assumed. Unless measurements are repeated over a long period, one or two low values of plasma renin cannot be considered a permanent marker indicating a special category of patients with essential hypertension. Tonin, a new enzyme discovered by Boucher, which forms angiotensin II directly from a plasma protein, from the tetradecapeptide substrate and from angiotensin I, is present in most tissues, but in highest concentration in the submaxillary gland. This enzyme is under the control of beta-adrenergic receptors.     

Angio-immunoblastic lymphadenopathy. Report of a case with pleural effusion.

A 78-year old man is presented with a characteristic case history and physical and laboratory findings typical of angio-immunoblastic lymphadenopathy with dysproteinemia (AILD). The disease had an acute onset with constitutional symptoms, generalized lymphadenopathy and hepato-splenomegaly. The presence of a large pleural effusion was of particular interest. Histologically the distinctive feature was a pronounced proliferation of small blood vessels and immunoblasts in the lymph nodes. Management of patient with AILD is problematic. Since AILD is a non-neoplastic process, symptomatic treatment with small doses of steroids, if necessary, would seem to be the best therapeutic approach. However, in our patient, as well as in other cases reported in the literature, a rapid and long standing (18 months so far in our case) complete remission was obtained with a short cycle of chemiotherapy.     

Toxicity of Trimethoprim-Sulphamethoxazole in Patients with Megaloblastic Haemopoiesis

Four consecutive patients with megaloblastic anaemia who also received therapy with trimethoprim-sulphamethoxazole all showed poor responses to specific haematinic therapy. This was attributed to trimethoprim, which suppressed reticulocyte responses in three cases and produced a pancytopenia in two and a falling haemoglobin with neutropenia in a third. A fourth patient, with pernicious anaemia, had a satisfactory reticulocyte response but experienced no clinical benefit until after withdrawal of trimethoprim.Trimethoprim seems not to be a safe form of therapy in patients with a megaloblastic process; many of the toxic reactions reported with this drug may be on the basis of an unrecognized megaloblastic form of haemopoiesis.     

Pulse oximetry at the roadside: a study of pulse oximetry in immediate care.

The measurement of tissue oxygen saturation with a pulse oximeter is of proved value in the hospital setting. The development of a portable oximeter has allowed this investigation to be performed during the prehospital phase of a patient''s care. Pulse oximetry was performed at the roadside in 25 patients with abnormal trauma scores and found to be of benefit in detecting and monitoring hypoxia in patients with airway obstruction, depressed respiration due to head injury, and, in particular, with closed chest injuries. There were no practical difficulties associated with the use of the instrument either at the roadside or in a moving ambulance. The portable pulse oximeter is a valuable aid in the prehospital monitoring of patients with trauma.     

Do Bells Affect Behaviour and Heart Rate Variability in Grazing Dairy Cows?

In alpine regions cows are often equipped with bells. The present study investigated the impact of wearing a bell on behaviour and heart rate variability in dairy cows. Nineteen non-lactating Brown-Swiss cows with bell experience were assigned to three different treatments. For 3 days each, cows were equipped with no bell (control), with a bell with inactivated clapper (silent bell) or with a functional bell (functional bell). The bells weighed 5.5 kg and had frequencies between 532 Hz and 2.8 kHz and amplitudes between 90 and 113 dB at a distance of 20 cm. Data were collected on either the first and third or on all 3 days of each treatment. Whereas duration of rumination was reduced with a functional bell and a silent bell compared with no bell, feeding duration was reduced with a silent bell and was intermediate with a functional bell. Head movements were reduced when wearing a silent bell compared with no bell and tended to be reduced when wearing a functional compared to no bell. With a functional bell, lying duration was reduced by almost 4 hours on the third day of treatment compared with the first day with a functional bell and compared with no bell or a silent bell. All additional behavioural measures are consistent with the hypothesis of a restriction in the behaviour of the cows wearing bells, although this pattern did not reach significance. There was no treatment effect on heart rate variability, suggesting that the bells did not affect vago-sympathetic balance. An effect of experimental day was found for only 1 out of 10 behavioural parameters, as shown by a decrease in lying with a functional bell on day 3. The results indicate behavioural changes in the cows wearing a bell over 3 days, without indication of habituation to the bell. Altogether, the behavioural changes suggest that the behaviour of the cows was disturbed by wearing a bell. If long-lasting, these effects may have implications for animal welfare.     

Analysis of the molecular interaction of the farnesyl moiety of transducin through the use of a photoreactive farnesyl analogue

Farnesylation of the gamma-subunit of the retinal G-protein, transducin (Talpha/Tbetagamma), is indispensable for light-initiated signaling in photoreceptor cells. However, the farnesyl-mediated molecular interactions important for signaling are not well understood. To explore this issue, we created a functional Tbetagamma analogue in which the farnesyl group was replaced with a (3-azidophenoxy)geranyl (POG) group, a novel farnesyl analogue with a distal photoreactive azido group. In the presence of lipid membranes and/or Talpha-GDP, UV irradiation of POG-modified Tbetagamma (POG-Tbetagamma) invariably yielded a cross-linked product Tgamma-Tbeta, reflecting a constitutive interaction of the Tgamma C-terminal lipid with Tbeta. In addition to the Tgamma-Tbeta adduct, a Tgamma-Talpha cross-link was detected in the aqueous fraction. Reconstitution of POG-Tbetagamma with Talpha and light-activated rhodopsin (Rh) in photoreceptor membranes resulted in cross-linking of Tgamma with a glycerophospholipid, indicating molecular interaction of the farnesyl group with cellular membranes. The Tgamma-phospholipid cross-link was observed only in the presence of both Talpha-GDP and Rh, and was abolished by the addition of GTPgammaS or by replacing Rh with opsin. These findings suggest a transient farnesyl-membrane interaction occurs only in a signaling state formed in a transducin-Rh ternary complex. On the other hand, UV irradiation of POG-Tbetagamma in a soluble complex with phosducin, a negative regulator of G-protein, yielded a Tgamma-phosducin adduct in addition to the Tgamma-Tbeta cross-link. These results illustrate that, rather than being a static membrane anchor, the farnesyl moiety plays an active role in the dynamics of protein-protein and protein-membrane interactions at defined steps in the signal transduction process.     

Oscillations in cell shape and size during locomotion and in contractile activities of Physarum polycephalum, Dictyostelium discoideum, Amoeba proteus and macrophages

Changes in cell shape and size were measured during locomotion, together with the motive force of the protoplasmic streaming, in various amoeboid cells in different stages of their life cycle, and under various environmental conditions. The variations in these measurements with time were examined by Fourier spectral analysis. Notwithstanding a change in cell type in the life cycle of P. polycephalum, myxamoebae and tiny plasmodia showed a similar time pattern of locomotion, exhibiting oscillations having a mixture of several periods. A regular oscillation with protoplasmic streaming appeared in the plasmodium only above a critical cell size. D. discoideum amoebae oscillated with two periods of a few minutes in preaggregation stage, but with a period of 10 min in aggregation stage, the latter being induced by cAMP. Macrophages and A. proteus also oscillated with periods of a few minutes. Periods of all these oscillations were prolonged severalfold by respiratory inhibition with NaCN, but were unaffected by glycolytic inhibition with 2-deoxyglucose. Cell fragments of A. proteus containing fewer granules oscillated more slowly and with a larger amplitude than those containing more granules. Among the granules, the nucleus was excluded as a possible modifier of the oscillation. The oscillation in Physarum plasmodium was reversibly suppressed by combining respiratory and ATPase inhibitions in mitochondria with NaCN and oligomycin, intracellular ATP concentration being kept at an appropriate level. The present results show that amoeboid motility, as well as cell shape, is oscillatory and that mitochondria are involved in time keeping.     

Repetitive mating and female fitness in Dysdercus cardinalis (Hemiptera: Pyrrhocoridae)

Using three mating-treatment groups–pairing with a male for life, pairing with a male from adult emergence to first oviposition, and no pairing (virgin)–of Dysdercus cardinalis females in a laboratory study, the following results were obtained. Most of the virgin females did not lay eggs; those that did oviposited for the first time at a considerably older age than females in the other two groups. In a lifetime, females pairing with a male for life and those pairing with a male up to first oviposition produced essentially the same number of eggs, and this was more than 3.5 times the number of eggs laid by a virgin female. Virgin females produced an average of 1.3 clutches in a lifetime, compared with about 4.5 clutches produced by females in the other two groups. Reproductive span was significantly shorter, and fecundity per day of reproductive span significantly greater, for females pairing with males for life than for those pairing with a male up to first oviposition. Age at death was significantly different amongst females in different mating-treatment groups. Virgin females had the longest life, followed by females pairing with a male up to first oviposition and females pairing with a male for life, in that order. There was a positive correlation between lifetime gross reproduction and age at death for females pairing with a male for life. There was no relationship between these two characters for females pairing with a male up to first oviposition. Both females pairing with a male for life and those pairing with a male to first oviposition exhibited a significant inverse relationship between fecundity per day and age at death. The results obtained indicate that (1) mating is a prerequisite for normal gonadal activity in Dysdercus cardinalis , and (2) repetitive mating increases the rate of reproduction. This would reduce the mean age of parenthood which is inversely related to the intrinsic rate of increase.     

Studies on the control of antibody synthesis. XVI. Effect of immunodepression on antibody affinity

The relationship between depression in the magnitude of the immune response and a decrease in affinity of the antibody produced was examined in three different models of immuno-depression (B-cell clonal deletion tolerance, specific suppressor T-cell activity, and anti-genie competition). In B-cell clonal deletion tolerance and in antigen-specific, suppressor T-cell-mediated immunodepression, a small decrease in magnitude (50% or less) is associated with a marked decrease in high-affinity, plaque-forming cells. In contrast, with nonspecific immunodepression, due to antigenic competition, a depression in affinity is only seen when there is a marked (85%) reduction in the magnitude of the response. The results are consistent with the view that when the mechanism of immunodepression involves interaction of antigen with antigen-specific B cells there is a disproportionate loss of high-affinity, antibody-producing cells relative to the decrease in magnitude. In contrast, with nonspecific immuno-depression, where the decrease in affinity is presumably due to inefficient expansion of high-affinity clones, an effect on affinity is only observed in association with a marked depression in the magnitude of the response.