bluuebunny/crossref_metadata_2025 huggingface dataset:
Significant abnormal glycemic variability increased the risk for arrhythmias in elderly type 2 diabetic patients
Authors: Zhang Jianbo , Yang Jianmin , Liu Liwei , Li Liyan , Cui Jiangyin , Wu Shuo , Tang Kuanxiao
Published: April 2021

Background

Little is known about whether the influence of glycemic variability on arrhythmia is related to age in type 2 diabetes mellitus (T2DM). Therefore, we aimed to compare the association between glycemic variability and arrhythmia in middle-aged and elderly T2DM patients.

Methods

A total of 107 patients were divided into two groups: elderly diabetes mellitus group (EDM, n = 73) and middle-aged diabetes mellitus group (MDM, n = 34). The main clinical data, continuous glucose monitoring (CGM) and dynamic ECG reports were collected. The parameters including standard deviation of blood glucose (SDBG), largest amplitude of glycemic excursions (LAGE), mean amplitude of glycemic excursions (MAGE), absolute means of daily differences (MODD), time in range (TIR), time below range (TBR), time above range (TAR), coefficient of variation (CV) were tested for glycemic variability evaluation.

Results

In terms of blood glucose fluctuations, MAGE (5.77 ± 2.16 mmol/L vs 4.63 ± 1.89 mmol/L, P = 0.026), SDBG (2.39 ± 1.00 mmol/L vs 2.00 ± 0.82 mmol/L, P = 0.048), LAGE (9.53 ± 3.37 mmol/L vs 7.84 ± 2.64 mmol/L, P = 0.011) was significantly higher in EDM group than those of MDM group. The incidences of atrial premature beat, couplets of atrial premature beat, atrial tachycardia and ventricular premature beat were significantly higher in EDM group compared with the MDM group (all P < 0.05). Among patients with hypoglycemia events, the incidences of atrial premature beat, couplets of atrial premature beat, atrial tachycardia and ventricular premature beat (all P < 0.05) were significantly higher in the EDM group than those in the MDM group. In EDM group, TIR was negatively correlated with atrial tachycardia in the MAGE1 layer and with atrial tachycardia and ventricular premature beat in the MAGE2 layer, TBR was significantly positively correlated with atrial tachycardia in the MAGE2 layer (all P < 0.05). In MDM group, TAR was positively correlated with ventricular premature beat and atrial tachycardia in the MAGE2 layer (all P < 0.05).

Conclusions

The study demonstrated the elderly patients had greater glycemic variability and were more prone to arrhythmias. Therefore, active control of blood glucose fluctuation in elderly patients will help to reduce the risk of severe arrhythmia.
Clinical and radiographic variables related to implants with simultaneous grafts among type 2 diabetic patients treated with different hypoglycemic medications: a retrospective study
Authors: Shi Shaojie , Ding Feng , Liu Xiangdong , Wang Lei , Wang Xingxing , Zhang Sijia , Zhao Guoqiang , Song Yingliang
Published: April 2021

Background

The influence of different hypoglycemic agents on peri-implant variables among type 2 diabetes mellitus patients is still unclear. Therefore, the aim of this study was to assess the radiographic marginal bone loss and clinical parameters around implants in patients using different hypoglycemic agents.

Methods

In this retrospective cohort study, the dental implant records of type 2 diabetes mellitus patients who met the inclusion criteria were collected. The patients using only single medication as follows: insulin, metformin, or glucagon-like peptide-1 (GLP-1) drugs, were grouped according to their medication. These patients received implant placement with the same initial status, and all the prosthesis restorations were cement-retained ceramic crowns. The peri-implant marginal bone levels were evaluated by periapical radiographs immediately after implant placement and at 1 and 2-year follow-up visits. The baseline characteristics were compared among groups. The peri-implant radiographic marginal bone loss and clinical parameters were preliminarily compared using the Kruskal–Wallis test, and then the covariates were controlled by covariance analysis. Bonferroni post hoc adjustment test was performed for the multiple comparisons.

Results

After a review of more than 7000 medical records, a total of 150 patients with 308 implants at 1-year follow-up were assessed. The peri-implant marginal bone loss in the GLP-1 drug group was significantly smaller than the insulin group and metformin group (P < 0.01). The radiographic bone loss in the metformin group was higher than the insulin group (P < 0.05). Some of these included patients were lost to follow-up. Only 74 patients with 129 implants completed the 2-year follow-up. The radiographic bone loss in the metformin group was still higher than the insulin group (P < 0.05) and GLP-1 group (P < 0.01). There was no significant difference in the BOP (+) and the mean PD among groups (P > 0.05).

Conclusions

The radiographic variables were not exactly the same among the patients with different hypoglycemic agents at both the 1 and 2-year follow-ups. After ensuring consistency in baseline characteristics, the positive effect of GLP-1 drugs on peri-implant bone remodeling may be no less than insulin or metformin. More studies are needed to verify the direct effect of these drugs on peri-implant bone.

Clinical trial registration number ChiCTR2000034211 (retrospectively registered).
Soluble receptor for advanced glycation end products (sRAGE) as a biomarker of COPD
Authors: Pratte Katherine A. , Curtis Jeffrey L. , Kechris Katerina , Couper David , Cho Michael H. , Silverman Edwin K. , DeMeo Dawn L. , Sciurba Frank C. , Zhang Yingze , Ortega Victor E. , O’Neal Wanda K. , Gillenwater Lucas A. , Lynch David A. , Hoffman Eric A. , Newell John D. , Comellas Alejandro P. , Castaldi Peter J. , Miller Bruce E. , Pouwels Simon D. , Hacken Nick H. T. ten , Bischoff Rainer , Klont Frank , Woodruff Prescott G. , Paine Robert , Barr R. Graham , Hoidal John , Doerschuk Claire M. , Charbonnier Jean-Paul , Sung Ruby , Locantore Nicholas , Yonchuk John G. , Jacobson Sean , Tal-singer Ruth , Merrill Debbie , Bowler Russell P.
Published: April 2021

Background

Soluble receptor for advanced glycation end products (sRAGE) is a proposed emphysema and airflow obstruction biomarker; however, previous publications have shown inconsistent associations and only one study has investigate the association between sRAGE and emphysema. No cohorts have examined the association between sRAGE and progressive decline of lung function. There have also been no evaluation of assay compatibility, receiver operating characteristics, and little examination of the effect of genetic variability in non-white population. This manuscript addresses these deficiencies and introduces novel data from Pittsburgh COPD SCCOR and as well as novel work on airflow obstruction. A meta-analysis is used to quantify sRAGE associations with clinical phenotypes.

Methods

sRAGE was measured in four independent longitudinal cohorts on different analytic assays: COPDGene (n = 1443); SPIROMICS (n = 1623); ECLIPSE (n = 2349); Pittsburgh COPD SCCOR (n = 399). We constructed adjusted linear mixed models to determine associations of sRAGE with baseline and follow up forced expiratory volume at one second (FEV1) and emphysema by quantitative high-resolution CT lung density at the 15th percentile (adjusted for total lung capacity).

Results

Lower plasma or serum sRAGE values were associated with a COPD diagnosis (P < 0.001), reduced FEV1 (P < 0.001), and emphysema severity (P < 0.001). In an inverse-variance weighted meta-analysis, one SD lower log10-transformed sRAGE was associated with 105 ± 22 mL lower FEV1 and 4.14 ± 0.55 g/L lower adjusted lung density. After adjusting for covariates, lower sRAGE at baseline was associated with greater FEV1 decline and emphysema progression only in the ECLIPSE cohort. Non-Hispanic white subjects carrying the rs2070600 minor allele (A) and non-Hispanic African Americans carrying the rs2071288 minor allele (A) had lower sRAGE measurements compare to those with the major allele, but their emphysema-sRAGE regression slopes were similar.

Conclusions

Lower blood sRAGE is associated with more severe airflow obstruction and emphysema, but associations with progression are inconsistent in the cohorts analyzed. In these cohorts, genotype influenced sRAGE measurements and strengthened variance modelling. Thus, genotype should be included in sRAGE evaluations.
The effects of cages implantation on surgical and adjacent segmental intervertebral foramina
Authors: Wu Changyan , Yang Xiaojuan , Gao Xu , Shao Liwei , Li Fang , Sun Yunxin , Liu Xiaoyu , Yao Shuaihao , Sun Yifu
Published: April 2021

Objection

The overarching goal of our research was to compare the clinical and radiological outcomes with different sizes of cages implantation in anterior cervical discectomy and fusion (ACDF), and to evaluate the effects on surgical and adjacent segmental intervertebral foramina.

Methods

The clinical data of 61 patients were analyzed retrospectively. The radiological data included the surgical intervertebral disk space height before (H0) and after surgery (H), the preoperative mean height of adjacent segments (Hm), the area and height of the surgical and adjacent segment foramen, the surgical segmental Cobb angle (α1), and C2-7Cobb angle (α2). The calculation of clinical data was conducted by Japanese Orthopaedic Association Scores (JOA), the recovery rate of JOA scores and visual analog scales (VAS). In accordance with the different ranges of distraction (H/Hm), patients were classified into three groups: group A (H/Hm<1.20, n=13), group B (1.20≤H/Hm≤1.80, n=37), and group C (H/Hm>1.80, n=11).

Results

After the operation and at the final follow-up, our data has demonstrated that the area and height of surgical segmental foramen all increased by comparing those of preoperation in three groups (all P<0.05). However, except for a decrease in group C (all P<0.05), the adjacent segmental foramina showed no significant changes (all P>0.05). The area and height of the surgical segment foramen and the distraction degree were positively correlated (0<R<1, all P<0.05), while the adjacent segments were negatively correlated with it (0<R<1, P=0.002~0.067). JOA scores improved markedly in all groups with similar recovery rates. However, during the final follow-up (P=0.034), it was observed that there were significant differences in visual simulation scores among the three groups.

Conclusion

The oversize cage might give a rise to a negative impact on the adjacent intervertebral foramen in ACDF. The mean value of the adjacent intervertebral disk space height (Hm) could be used as a reference standard. Moreover, the 1.20~1.80 fold of distraction (H/Hm) with optimal cages would achieve a better long-term prognosis.
Minimally invasive plate osteosynthesis using the oblong hole of a locking plate for comminuted distal fibular fractures
Authors: Park Young Uk , Kim Sung Jae , Kim Hyong Nyun
Published: April 2021

Background

Nonunion is a rare complication for distal fibular fractures. However, when there is a high degree of comminution, nonunion may occur. In this article, we describe a novel technique that uses the oblong hole of a locking plate to lengthen the fibula for fracture reduction. This technique is straightforward and allows for easy control of the comminuted fracture to restore length and rotation at the time of plate application without opening the fracture site.

Methods

Thirty-five consecutive patients, who were treated with the minimally invasive plate osteosynthesis (MIPO) technique for comminuted distal fibular fractures were retrospectively studied. The study included 19 men and 16 women, with a mean age of 47.0 years (range, 20 to 72). There were 3 lateral malleolar fractures with deltoid injury, 11 bimalleolar fractures, 7 trimalleolar fractures, and 14 distal tibiofibular fractures. The quality of fracture reduction was assessed by comparing the radiologic parameters (fibular length, talocrural angle, and medial clear space) between the affected ankle and the contralateral uninjured ankle.

Results

Two patients were not reachable and 5 declined to visit the clinic. For these 7 patients, the latest outcomes that were measured prospectively were used. Postoperative radiographs showed well-aligned ankle mortise, with fibular length restoration. The mean Olerud-Molander ankle score was 82.1 ± 10.7 at a mean of 27.2 months (range, 12 to 58). There was one case of nonunion and one case of superficial peroneal nerve injury.

Conclusion

The MIPO technique, using the oblong hole of a locking plate, achieved satisfactory restoration of length and rotation, bone union, and clinical outcomes for the comminuted distal fibular fractures.
Periplasmic synthesis and purification of the human prolactin antagonist Δ1-11-G129R-hPRL
Authors: Suzuki Miriam F. , Almeida Larissa A. , Pomin Stephanie A. , Silva Felipe D. , Freire Renan P. , Oliveira João E. , Affonso Regina , Soares Carlos R. J. , Bartolini Paolo
Published: April 2021

The human prolactin antagonist Δ1-11-G129R-hPRL is a 21.9 kDa recombinant protein with 188 amino acids that downregulates the proliferation of a variety of cells expressing prolactin receptors. Periplasmic expression of recombinant proteins in E. coli has been considered an option for obtaining a soluble and correctly folded protein, as an alternative to cytoplasmic production. The aim of this work was, therefore, to synthesize for the first time, the Δ1-11-G129R-hPRL antagonist, testing different activation temperatures and purifying it by classical chromatographic techniques. E. coli BL21(DE3) strain was transformed with a plasmid based on the pET25b( +) vector, DsbA signal sequence and the antagonist cDNA sequence. Different doses of IPTG were added, activating under different temperatures, and extracting the periplasmic fluid via osmotic shock. The best conditions were achieved by activating at 35 °C for 5 h using 0.4 mM IPTG, which gave a specific expression of 0.157 ± 0.015 μg/mL/A600 at a final optical density of 3.43 ± 0.13 A600. Purification was carried out by nickel-affinity chromatography followed by size-exclusion chromatography, quantification being performed via high-performance size-exclusion chromatography (HPSEC). The prolactin antagonist was characterized by SDS-PAGE, Western blotting, reversed-phase high-performance liquid chromatography (RP-HPLC) and MALDI-TOF–MS. The final product presented > 95% purity and its antagonistic effects were evaluated in vitro in view of potential clinical applications, including inhibition of the proliferation of cancer cells overexpressing the prolactin receptor and specific antidiabetic properties, taking also advantage of the fact that this antagonist was obtained in a soluble and correctly folded form and without an initial methionine.
Inheritors of the Yellow River: the relationship of heritage making practices to cultural self-confidence in China
Authors: Zhang Wanlin , Walker Stuart , Evans Martyn , Bennett Julia
Published: April 2021

Through active involvement in UNESCO’s ICH (Intangible Cultural Heritage) programme, China has developed its own framework to support traditional making practices. To examine the ‘characteristics’ of heritage crafts preservation in China, we undertook empirical research in the Yellow River basin. Our research involved in-depth observations and key informant interviews with a range of highly accomplished craftspeople who have inherited their particular expertise from their family and have been officially designated ICH Inheritors. Through our qualitative research with inheritors, a businessperson and a government official, we identified various support mechanisms employed by the Chinese government that aim to protect traditional culture while also recognising outstanding individuals. We also found that ICH Inheritors play an important role in raising cultural awareness and enhancing cultural confidence through their creative activities and making practices, craft businesses and transfer of expertise. Based on the findings, potential areas where designers may collaborate with inheritors were identified.
Concordance of 24- and 48-h diagnostic follow-up ascitic fluid polymorphonuclear leukocyte count in the guidance of the antibiotic therapy in spontaneous bacterial peritonitis
Authors: Badran Hanaa Mostafa , Elsabaawy Maha Mohammad , Mahmoud Mohamed Azazy , Ghanem Heba Samy , Alsebaey Ayman , Othman Warda
Published: April 2021

Background

Spontaneous bacterial peritonitis (SBP) is an ascitic fluid infection in patients with liver cirrhosis in the absence of surgical causes. The drop of the ascitic fluid polymorphonuclear leukocyte count (AFPC) ≥25% of baseline 48h post-start of antibiotics is a predictor of antibiotic response. This study was designed to compare the diagnostic accuracy of AFPC 24h of antibiotic to the standard 48h. Three hundred ninety-nine SBP patients were classified into 2 groups. Group I (31.1%) are patients that lacked ≥25% drop and group II (68.9%) the opposite.

Results

The average age was 51.99 ±11.21 years. Most patients were males (70.9%), normotensive (75.8%), non-diabetics (50.8%), and without recent intake history of proton pump inhibitors (75.8%) and B-blockers (77%). Group II patients had statistically significant (p <0.05) serum sodium 129 (7) vs. 128 (8) and history of diabetes mellitus 60.3% vs. 39.7%. The baseline AFPC did not differ statistically between groups I and II (p>0.05). Group II patients compared to group I had statistically (p =0.001) lower AFPC 24h [800 (970) vs. 1100 (1700) cell/mm3], higher percent drop of the AFPC 24h [28.09 (24) vs. −10.17 (35)], and ≥25% drop [154 (90.6%) vs. 16 (9.4%)]. The 24h AFPC >980 cell/mm3 was associated with AFPC 48h non-response (AUROC =0.634, p =0.001, 58.87% sensitivity, 64.36% specificity). The 24-h AFPC percent drop >8% was associated with AFPC 48h response (AUROC =0.849, p=0.001, 85.82% sensitivity, 80.49% specificity).

Conclusion

Concordance of 24- and 48-h diagnostic follow-up ascitic fluid polymorphonuclear leukocyte count in the guidance of the antibiotic therapy.
COVID-19 and Thyroid Diseases: A Bidirectional Impact
Authors: Duntas Leonidas H , Jonklaas Jacqueline
Published: April 2021

Context

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has become the most lethal and rapidly moving pandemic since the Spanish influenza of 1918-1920, is associated with thyroid diseases.

Methods

References were identified through searches of PubMed and MEDLINE for articles published from Jan 1, 2019 to February 19, 2021 by use of the MeSH terms “hypothyroidism”, “hyperthyroidism”, “thyroiditis”, “thyroid cancer”, “thyroid disease”, in combination with the terms “coronavirus” and “COVID-19”. Articles resulting from these searches and references cited in those articles were reviewed.

Results

Though preexisting autoimmune thyroid disease appears unlikely to render patients more vulnerable to COVID-19, some reports have documented relapse of Graves’ disease (GD) or newly diagnosed GD about 1 month following SARS-CoV-2 infection. Investigations are ongoing to investigate molecular pathways permitting the virus to trigger GD or cause subacute thyroiditis (SAT). While COVID-19 is associated with non-thyroidal illness, it is not clear whether it also increases the risk of developing autoimmune hypothyroidism. The possibility that thyroid dysfunction may also increase susceptibility for COVID-19 infection deserves further investigation. Recent data illustrate the importance of thyroid hormone in protecting the lungs from injury, including that associated with COVID-19.

Conclusion

The interaction between the thyroid gland and COVID-19 is complex and bidirectional. COVID-19 infection is associated with triggering of GD and SAT, and possibly hypothyroidism. Until more is understood regarding the impact of coronavirus on the thyroid gland, it seems advisable to monitor patients with COVID-19 for new thyroid disease or progression of preexisting thyroid disease.
How Marcel Proust Can Change Your Life—For Better or for Worse
Authors: Bloch R. Howard , Spitz Ellen Handler
Published: April 2021

This article turns around the role that Proust’s novel played—for better or worse—in my formation as a medievalist and as a full human being. In the curé’s obsession with genealogy and etymology, I recognized in the 1970s a deep medieval mental structure that coincided with contemporaneous work by historians of the Annales School on lineage and by structuralists on the linguistic patterns underpinning kinship. This led to a book, Etymologies and Genealogies: A Literary Anthropology of the French Middle Ages. But other strong strains of the Proustian sentimental orbit, doomed love, aligned chronologically and conceptually with the articulation in the 1890s of courtly love and made for dire consequences in a life lived along those lines. My wife, Ellen Handler Spitz, provides an emotionally corrective experience via the question, Was Swann in Love? Using the psychoanalytic concept of the partial object, she shows how limited Proust’s notion of love really is. We end on a note of wild admiration for Proust’s description of what it feels like to be in what he calls “love” but with a dose of skepticism with regard to his framing of the project of love itself.
The Invalid
Authors: Holleran Andrew
Published: April 2021

“The Invalid” is an autobiographical account of one American novelist’s reading Proust over the course of his life. After the initial impact of encountering Remembrance of Things Past as a young soldier in 1968 Germany, he is forced to wonder: Did Proust bring the novel to an end? Could there be an American equivalent to his novel? And why among writers is there a saying, “If you want to write like Proust, don’t write like Proust”? Searching for the key to Proust’s achievement, the author realizes that over the years he has possibly read more about Proust than he has Proust. And yet, as an invalid himself toward the end of his life, he can only conclude that the novel is inimitable.
Inactivation of erythropoietin leads to defects in cardiac morphogenesis
Authors: Wu Hong , Lee Sang Hoon , Gao Jing , Liu Xin , Iruela-Arispe M. Luisa
Published: April 2021

Erythropoietin is an essential growth factor that promotes survival, proliferation, and differentiation of mammalian erythroid progenitor cells. Erythropoietin−/− and erythropoietin receptor−/− mouse embryos die around embryonic day 13.5 due, in part, to failure of erythropoiesis in the fetal liver. In this study, we demonstrated a novel role of erythropoietin and erythropoietin receptor in cardiac development in vivo. We found that erythropoietin receptor is expressed in the developing murine heart in a temporal and cell type-specific manner: it is initially detected by embryonic day 10.5 and persists until day 14.5. Both erythropoietin−/− and erythropoietin receptor−/− embryos suffered from ventricular hypoplasia at day 12-13 of gestation. This defect appears to be independent from the general state of hypoxia and is likely due to a reduction in the number of proliferating cardiac myocytes in the ventricular myocardium. Cell proliferation assays revealed that erythropoietin acts as a mitogen in cells isolated from erythropoietin−/− mice, while it has no effect in hearts from erythropoietin receptor−/− animals. Erythropoietin−/− and erythropoietin receptor−/− embryos also suffered from epicardium detachment and abnormalities in the vascular network. Finally, through a series of chimeric analysis, we provided evidence that erythropoietin acts in a manner which is non-cell-autonomous. Our results elucidate a novel role of erythropoietin in cardiac morphogenesis and suggest a combination of anemia and cardiac failure as the cause of embryonic lethality in the erythropoietin−/− and erythropoietin receptor−/− animals.
Regulation of differential growth in the apical hook of Arabidopsis
Authors: Raz Vered , Ecker Joseph R.
Published: April 2021

Arabidopsis seedlings develop a hook-like structure at the apical part of the hypocotyl when grown in darkness. Differential cell growth processes result in the curved hypocotyl hook. Time-dependent analyses of the hypocotyl showed that the apical hook is formed during an early phase of seedling growth and is maintained in a sequential phase by a distinct process. Based on developmental genetic analyses of hook-affected mutants, we show that the hookless mutants (hls1, cop2) are involved in an early aspect of hook development. From time-dependent analyses of ethylene-insensitive mutants, later steps in hook maintenance were found to be ethylene sensitive. Regulation of differential growth was further studied through examination of the spatial pattern of expression of two hormone-regulated genes: an ethylene biosynthetic enzyme and the ethylene receptor ETR1. Accumulation of mRNA for AtACO2, a novel ACC (1-aminocyclopropane-1-carboxylic acid) oxidase gene, occurred within cells predominantly located on the outer-side of the hook and was tightly correlated with ethylene-induced exaggeration in the curvature of the hook. ETR1 expression in the apical hook, however, was reduced by ethylene treatment. Based on the expression pattern of ETR1 and AtACO2 in the hook-affected mutants, a model for hook development and maintenance is proposed.
Genes required for axon pathfinding and extension in the C. elegans nerve ring
Authors: Zallen Jennifer A. , Kirch Susan A. , Bargmann Cornelia I.
Published: April 2021

Over half of the neurons in Caenorhabditis elegans send axons to the nerve ring, a large neuropil in the head of the animal. Genetic screens in animals that express the green fluorescent protein in a subset of sensory neurons identified eight new sax genes that affect the morphology of nerve ring axons. sax-3/robo mutations disrupt axon guidance in the nerve ring, while sax-5, sax-9 and unc-44 disrupt both axon guidance and axon extension. Axon extension and guidance proceed normally in sax-1, sax-2, sax-6, sax-7 and sax-8 mutants, but these animals exhibit later defects in the maintenance of nerve ring structure. The functions of existing guidance genes in nerve ring development were also examined, revealing that SAX-3/Robo acts in parallel to the VAB-1/Eph receptor and the UNC-6/netrin, UNC-40/DCC guidance systems for ventral guidance of axons in the amphid commissure, a major route of axon entry into the nerve ring. In addition, SAX-3/Robo and the VAB-1/Eph receptor both function to prevent aberrant axon crossing at the ventral midline. Together, these genes define pathways required for axon growth, guidance and maintenance during nervous system development.
The In Vitro assembly of tubulins from sea-urchin eggs and rat brain: Use of heterologous seeds
Authors: Burns R. G. , Starling D.
Published: April 2021

Sea-urchin tubulins can be assembled in vitro to form microtubules provided that a suitable seed is present. Although fragments of sea-urchin microtubules fail to act as seeds, since they apparently dissociate, short pieces of rat brain microtubule will act as nucleation sites for the assembly of sea-urchin tubulins. In addition, rat brain tubulins appear to undergo a certain amount of in vitro assembly when seeded with fragments of microtubules derived from seaurchin sperm tails. Assembly on a heterologous seed indicates that the current in vitro assembly conditions may be insufficiently stringent.
The distribution of concanavalin a receptor sites on the membrane of chromaffin granules
Authors: Eagles P. A. M. , Johnson L. N. , Horn C. Van
Published: April 2021

The distribution of concanavalin A (con A) receptor sites on the membranes of chromaffin granules has been investigated by binding studies using 125I-labelled con A and by electron-microscope studies using ferritin-labelled con A. In both experiments con A was observed to bind to chromaffin granule membranes but not to intact granules. The ferritin-con A particles bind to only one of the two possible surfaces of the chromaffin granule membranes. These results are in agreement with previous observations concerning the asymmetric distribution of saccharide residues on the surfaces of a number of different plasma membranes. They suggest that for the intracellular membrane of the chromaffin granule the saccharide sites, like those in plasma membranes, are not exposed to the cell cytoplasm. Further work is necessary to establish whether these sites are on the inner surface of the membrane or whether they are unmasked during the conversion of granules to membrane ghosts.
Mg2+-Dependent electrical control of flagellar activity in Euglena
Authors: Nichols Kathleen M. , Rikmenspoel Robert
Published: April 2021

When a Euglena gracilis in a Ca2+-containing medium is impaled with a microelectrode, the flagellum is instantly ejected. In a Ca2+-free medium to which 1mM EGTA has been added, the flagellum remains attached to the organism, but it loses activity upon impalement. Externally added ATP at a concentration of 10 mM will sustain normal flagellar activity (at approximately 20 Hz) of an impaled Euglena. If negative direct current of several tenths of a microamp is injected through the impaling microelectrode, the flagellar activity is stopped or much reduced. When the current injection is turned off the flagellum returns to its initial activity. This cyclo can be repeated many times on the same animal, independent of whether Mg2+ is present in the external medium or not. If 1 μM of gramicidin is added to Ca2+-free medium containing 1mM EGTA and 10 mM ATP, the flagellar activity becomes dependent on external Mg2+. Without external Mg2+ no flagellar activity is present after one or two current injection cycles as described above. With 1 mM Mg2+ present in the external medium many cycles (up to 10) can be produced. This Mg2+-dependent flagellar activity shows a smooth dependence on the amount of current injected. Observations taken by high speed cinemicrography show that in the third injection cycle the average frequency of the flagellar motion is 16 ·3 Hz at 0 μA, is 8 Hz at 0 ·2 μA, and is ≈ 0 at 0 ·6 μA of negative current. The injection of positive current results in an increase in flagellar frequency dependent on the amount of current injected. The data indicate that the control of motility of Euglena flagella is dependent on an electrically activated Mg2+ pump.
Mechanochemical coupling in flagella : V. effects of viscosity on movement and atp-dephosphorylation of triton- demembranated sea-urchin spermatozoa
Authors: Brokaw C.J. , Simonick T. F.
Published: April 2021

Improved techniques have been used to measure movement-coupled ATP-dephosphorylation by suspensions of motile, reactivated sea-urchin spermatozoa. The results confirm that the movement-coupled ATP-dephosphorylation is proportional to beat frequency under conditions where the bend angle remains constant. Some observations suggest that the rate of ATP- dephosphorylation is also related to the amplitude of sliding between flagellar tubules, but our attempts to measure this relationship have been unsuccessful.
Phase-randomized laser illumination for microscopy
Authors: Hard Robert , Zeh Robert , Allen Robert D.
Published: April 2021

A simple apparatus is described that phase randomizes the output of a continuous argon ion laser, so that it may be used as a source of high intensity, monochromatic light for microscopy. The phase-randomizing device can be used with any laser, polarized or unpolarized, and of any desired power output and wavelength, including dye lasers for spectral studies. The randomizing system can be adapted to any light microscope and any optical system including bright-field, phase-contrast, Nomarski differential-interference, dark-field, and split-beam interference systems such as the Jamin-Lebedeff System. It can be used for a variety of photometric and photographic studies. The 514-nm wavelength appears to be relatively harmless to a variety of cells.
Red blood cell adhesion: I. determination of the ionic conditions for adhesion to an oil-water interface
Authors: Todd Ian , Gingell David
Published: April 2021

We have examined the adhesion of glutaraldehyde-treated human red blood cells to a clean liquid hydrocarbon interface as a function of sodium chloride concentration. Cells adhere reversibly to the interface over a wide range of concentrations but fail to do so below about 0·1 mM. Adherent cells do not alter the tension of the oil/water interface.

These results show that cells can adhere by physical forces in special situations without biochemical interactions. The data provide a basis for calculating the size of the physical forces.
Biochemical and ultrastructural studies on flight muscle mitochondria from the blowfly Calliphora erythrocephala following treatment by chloramphenicol and ethidium bromide
Authors: Ashour Badr , Tribe Michael , Danks Susan , Whittaker Peter
Published: April 2021

Adult blowflies were injected during the first day after eclosion with various concentrations of the drugs chloramphenicol and ethidium bromide. Previous experiments had shown that these drugs inhibit mitochondrial protein synthesis and at high doses increase mortality.

Mitochondria isolated from blowflies 24 h after drug injection revealed a considerable decrease in oxidation rates when pyruvate plus proline were used as substrates. There was also a reduction up to 50 % in the respiratory control ratios obtained, though there was little change in the measurable ADP:O ratios. This loss in activity was commensurate with the finding that both drugs block the rapid increase in protein synthesis (expressed as mitochondrial protein content) during the period of observation. Examination of the cytochrome difference spectra 24 h after treatment again showed a decline in all major cytochrome peaks with increasing concentration of both drugs.

Examination of mitochondrial morphology in situ using electron microscopy revealed degenerative changes 24 h after treatment with high doses of both drugs. In particular, irregular alignment of cristae and extensive vacuolation were observed within the mitochondria.

The extent of decreased biochemical activity and morphological damage to mitochondria was clearly dependent on the concentration of drugs administered and such changes may be attributed primarily to a loss of certain polypeptide subunits coded for by mitochondrial DNA and synthesized on mitochondrial ribosomes.
Calcium-dependent shortening of fibroblasts induced by the ionophore, a23187
Authors: Goldfine S. M. , Schroter E. H. , Izzard C. S.
Published: April 2021

Attached, spread, chick heart fibroblasts were induced to shorten by treatment with the ionophore, A23187. The shortening resulted from the retraction of the leading lamellae and other major cell processes. The response was dependent on external calcium with a threshold close to, and a maximal effect at, physiological concentrations. The shortening was also induced in Colcemid-treated cells and therefore did not involve a depolymerization of microtubules. Indirect evidence indicates that the shortening was preceded by an increase in tension in the spread cell. The response is consistent with the effect of an increase in the cytoplasmic concentration of free calcium on a calcium-sensitive actomyosin system in the spread fibroblast. Although the retraction of non-spreading processes mimicked the intermittent retraction of similar trailing processes during normal movement of fibroblasts, the response to the ionophore differed in that the leading lamellae were also induced to retract. This difference implies that a general increase in the cytoplasmic concentration of free calcium alone cannot account for the intermittent shortening that occurs in normal movement.
Dependence of cell-type proportioning and sorting on cell cycle phase in Dictyostelium discoideum
Authors: Weijer Corneeis J. , Duschl Gertrud , David Charles N.
Published: April 2021

The relationship between the cell cycle phase of vegetative amoebae and prestalk and prespore differentiation in the slug stage were investigated in the slime mould Dictyostelium discoideum. Cells were synchronized by release from the stationary phase. Samples were taken at various times during the course of a synchronous cell doubling, fluorescently labelled and mixed with cells of random cell cycle phase from exponentially growing cultures. The fate of the fluorescently labelled cells was recorded at the slug stage. Cells early in the cycle exhibit strong prestalk sorting; cells taken later in the cycle exhibit strong prespore sorting. The period of prestalk sorting occurs immediately following mitosis and lasts about 1 h in a cell cycle of about 7 h duration. Accompanying the altered sorting behaviour is a marked change in the prestalk-prespore proportions in slugs formed from synchronized populations of cells. Cells synchronized early in the cycle form slugs with 55% prespore cells; cells synchronized late in the cycle form slugs with 90% prespore. The results are discussed in terms of models for the formation of the prestalk-prespore pattern in slugs.
Effect of substrate composition on bone resorption by rabbit osteoclasts
Authors: Chambers T. J. , Thomson B. M. , Fuller K.
Published: April 2021

Slices of human femoral cortical bone were prepared with a carborundum wheel. Osteoclasts were isolated from neonatal rabbit long bones and incubated on either untreated, demineralized or anorganic preparations of these bone slices. Anorganic bone showed extensive tracts of uninterrupted surface excavation after incubation, while untreated bone tended to show discontinuous excavations of smaller total volume; demineralized bone was not resorbed. The endosteal surface of adult rat calvaria was also used as a substrate for osteoclastic bone resorption. The endosteal surface was exposed and rendered acellular, and was used either without further treatment or after incubation in collagenase. Bone resorption occurred only in those calvaria pre-treated with collagenase.

These experiments imply that osteoclastic contact with bone mineral rather than the endosteal surface is the stimulus that initiates bone-resorptive behaviour in osteoclasts. The mechanism by which osteoblasts induce osteoclastic bone resorption may be through the known ability of osteoblasts to secrete collagenase, which, by digestion of the unmineralized lamina limitans of endosteal surfaces, exposes bone mineral to osteoclastic contact.
Glial toxin effect on protein synthesis in an insect connective
Authors: Smith P. J. S. , Howes E. A.
Published: April 2021

Analysis of electron autoradiographs from the nerve cord of the insect, Periplaneta americana (L.) shows a significant incorporation of 3H-labelled protein in the axons. The axonal activity is greatly reduced after treatment of the cord with the glial toxin ethidium bromide. This is interpreted as substantiating the possibility that adaxonal glia can transfer proteins to the axons.
Phorbol esters stimulate macropinocytosis and solute flow through macrophages
Authors: Swanson Joel A.
Published: April 2021

The morphology and kinetics of pinocytosis by bone marrow-derived macrophages were studied to determine how stimulation by phorbol esters increases net solute accumulation. Application of phorbol myristate acetate (PMA) increased both the abundance of macropinosomes and the rate of solute flow through the endocytic compartment. The large pinosomes originated as ruffles at the cell margins that folded back on themselves, internalizing extracellular medium and solutes. I examined how stimulation affects the kinetics of pinocytic influx, accumulation, and subsequent efflux of the fluorescent dye Lucifer Yellow (LY) in macrophages. Both the accumulation of LY and its subsequent efflux were temperature-dependent and directly proportional to the concentration of LY in the extracellular medium. Macrophages incubated in PMA and LY for 2 h accumulated four to six times more LY than did macrophages in LY alone. If after pinocytosis the macrophages were washed and reincubated in unlabeled medium for a 1h chase period, some of the internalized LY was regurgitated from the cells. Inclusion of PMA in the chase medium increased efflux of LY. In contrast, a smaller percentage of LY was regurgitated from macrophages which were both loaded and chased in the presence of PMA. This indicates that although efflux is increased by PMA, influx increases more, and therefore more of the LY entering by pinocytosis is retained within the cell. I suggest that macropinocytosis increases the size difference between pinosomes and efflux vesicles, and that that difference increases greatly both solute accumulation and membrane flow through the endocytic compartment.
Biochemical and immunocytochemical analysis of a histone H1 variant from the mouse testis
Authors: Rasheed B. K. A. , Whisenant E. C. , Ghai R. D. , Papaioannou V. E. , Bhatnagar Y. M.
Published: April 2021

An Hl histone variant, H1a, has been isolated and purified from the mouse testis. Biochemical and amino acid analyses indicate its similarity with the rat testis H1a. Specific antibodies against the purified H1a have been generated in rabbits and used to study its tissue and species distribution using protein blotting procedures. We have also used the immunocytochemical technique to determine in situ distribution of H1a in spermatogenic cells and somatic tissues of the mouse. A non-random distribution of H1a has been noted in the nuclei of certain somatic cell types such as Sertoli cells, Leydig cells and neurons. By contrast, hepatocyte nuclei lacked detectable levels of H1a. In adult seminiferous tubules, the early primary spermatocyte nuclei displayed a greater level of immunoreactivity relative to other cell types. Developmental studies indicate its initial expression in the 7-day-old mouse testis concomitant with the appearance of intermediate and type B spermatogonia.
Immunocytochemical study of the formation of striated rootlets during ciliogenesis in quail oviduct
Authors: Lemullois Michel , Marty Marie-Chantal
Published: April 2021

In quail oviduct, a 175K (K=103Mr) protein associated with striated rootlets was previously identified by Klotz and co-workers using monoclonal antibody CC310. As this monoclonal antibody recognizes several proteins on immunoblots of ciliated cells, we prepared a polyclonal antibody monospecific to the 175K protein by intrasplenic immunization of mice. Immunofluorescence study confirmed the distribution of the 175K protein at the apical part of the ciliated cell and its absence in other epithelial cells. Immunogold staining showed that this protein was strongly associated with the fibrillar axis of striated rootlets. The absence of labeling on striation suggested that rootlets were composed of several proteins, with one group forming the fibrillar axis and the second forming the striation. The formation of striated rootlets during ciliogenesis was studied using this polyclonal antibody. The 175K protein appeared at the beginning of centriologenesis in fibrillar material located around dense granules, and then around the generative complex. The formation of rootlets began at the basal pole of migrating basal bodies. The elongation of the rootlet axes took place when basal bodies were anchored to the plasma membrane.
Macrophage heterogeneity in bone marrow culture in vitro
Authors: Mori Masaharu , Sadahira Yoshito , Kawasaki Seiji , Hayashi Toshiko , Awai Michiyasu
Published: April 2021

Macrophages in mouse bone marrow cultures were investigated with macrophage-specific monoclonal antibody F4/80 and anti-Forssman glycosphingolipid (GSL) antibody, which was specific for macrophages in hematopoietic foci. Antibody F4/80 stained two types of cells, small macrophages and large flat macrophages associated with hematopoietic cells. The cytochemical and phagocytotic characteristics were similar between these two types of cells, but Forssman GSL was positive only for the large flat macrophages associated with hematopoietic cells. The data suggest that Forssman GSL positive macrophages, derived from resident bone marrow macrophages, play an important role in hematopoiesis and are clearly distinguished from small macrophages in vitro.
Microtubule-determined plastid distribution during microsporogenesis in Lilium longiflorum
Authors: Tanaka Ichiro
Published: April 2021

The relationship between organelle distribution and the cytoskeleton was examined during microsporogenesis in Lilium longiflorum. The distribution pattern of plastid and mitochondrial nucleoids was followed by fluorescence microscopy after staining with 4’,6-diamidino-2-phenylindoie (DAPI). Although the plastid nucleoids gradually enlarged during prophase I, by anaphase I of meiosis they were randomly distributed in the cytoplasm of each microsporocyte. At telophase I the plastid nucleoids were aggregated in the equatorial region of the cell. After entering prophase II the plastid nucleoids were randomly distributed in the cytoplasm, and at telophase II they had reaggregated to the equators of the two cells. After the completion of meiosis they were located at the two poles of each young microspore. This distinct cell polarity of plastid nucleoids was preserved in isolated protoplasts. In all cells where the distribution of plastid nucleoids was non-random, the nucleoids were invariably situated furthest away from the interphase and telophase nuclei. However, the distribution of mitochondrial nucleoids throughout meiotic division showed little cell polarity.

Analysis of the microtubule and actin cytoskeletons during microsporogenesis revealed that the microtubules radiated out from the cell nuclei only at the stages when the distribution of plastids showed polarity, whereas the actin filaments were usually randomly oriented throughout the cytoplasm, independent of the plastid arrangement and of the organization of microtubule cytoskeleton. The radiating microtubules seemed to exclude the plastids from around the cell nuclei. Treatment of cultured pollen tetrads with colchicine disrupted the plastid polarity, probably by depolymerizing the radiating microtubules, resulting in a random distribution of the plastid nucleoids. Treatment with cytochalasin B, however, had no effect on the arrangement of plastids.

These results demonstrate that microtubules function in the movement and distribution of plastids in male reproductive cells of higher plants. Further, it is assumed that the system of radiating microtubules that controls the distribution of plastids during male meiosis is also involved in the subsequent formation of male gametes, which are deficient in plastids in many angiosperm plants, including this lily.
Photoreception of Paramecium cilia: localization of photosensitivity and binding with anti-frog-rhodopsin IgG
Authors: Nakaoka Yasuo , Tokioka Ryo , Shinozawa Takao , Fujita Jun
Published: April 2021

Paramecium bursaria is photosensitive and accumulates in a lighted area. The cells can be deciliated by a brief suspension in dilute ethanol. Both intact and deciliated cells showed depolarization in response to light stimulation by a step-increase from dark to above 0.7 mW cm−2 (550 nm). On the other hand, after a step-increase to below 0·4mWcm−1, intact cells showed hyperpolarization, while the deciliated cells showed no change in membrane potential. This difference in membrane potential response between ciliated and deciliated cells suggests that both somatic and ciliary structures are photosensitive. In our search for the photoreceptive molecules, a polyclonal antibody induced in rabbits against frog rhodopsin was found to croos-react with a 63 × 103Mτ protein of P. bursaria, by Immunoelectrophoresis. Immunocytochemical studies showed that the antibody labeling was localized on both the ciliary and the somatic membranes. These results raise the possibility that P. bursaria may contain a rhodopsin-like protein as a photoreceptor molecule.