Compare the Centering Ability, Canal Transportation and Root Canal Area Increase of XP Endoshaper, Hyflex CM and K3 XF File System by using Cone Beam: An Original Research

Objective

Using cone beam computed tomography (CBCT), this study compared three rotary file systems-XP Endoshaper, Hyflex CM, and K3 XF-for centering, canal transportation, and root canal area growth.

Materials and Methods

The rotating file system randomly separated 60 removed human mandibular molars into three groups (n = 20). Manufacturer-recommended root canal instrumentation was done. Specialized software examined pre- and post-instrumentation CBCT scans. Centering ability was measured by canal transportation and root canal area expansion at different levels from the apex.

Results

The Hyflex CM file system had the best centering and the least canal transit at all levels (P < 0.05). XP Endoshaper increased the root canal area the most (P < 0.05). The K3 XF file system had average centering and canal transfer results.

Conclusion

The Hyflex CM system centered well, whereas the XP Endoshaper system increased the root canal area the most. The clinical context and therapeutic goals should determine the rotating file system.

Association between Sleep Quality and Mental Health among Patients at a Post-COVID-19 Recovery Clinic

A growing body of research documents the persistence of physical and neuropsychiatric symptoms following the resolution of acute COVID-19 infection. To the best of our knowledge, no published study has examined the interaction between insomnia and mental health. Accordingly, we proposed to examine new diagnoses of insomnia, and referrals to pulmonary and sleep medicine clinics for treatment of sleep disorders, in patients presenting to one post-acute COVID-19 recovery clinic. Additionally, we aimed to examine the relationship between poor sleep quality, depression, anxiety, and post-traumatic stress. Patients presented to the clinic on average 2 months following COVID-19 infection; 51.9% (n = 41) were hospitalized, 11.4% (n = 9) were in the intensive care unit, 2.5% (n = 2) were on a mechanical ventilator, and 38.0% (n = 30) were discharged on oxygen. The most commonly reported symptom was fatigue (88%, n = 70), with worse sleep following a COVID-19 infection reported in 50.6% (n = 40). The mean PSQI score was 9.7 (82.3%, n = 65 with poor sleep quality). The mean GAD-7 score was 8.3 (22.8%, n = 14 with severe depression). The mean PHQ-9 was 10.1 (17.8%, n = 18 with severe anxiety). The mean IES-6 was 2.1 (54.4%, n = 43 with post-traumatic stress). Poor sleep quality was significantly associated with increased severity of depression, anxiety, and post-traumatic stress. Future work should follow patients longitudinally to examine if sleep, fatigue, and mental health symptoms improve over time.

Impact of socio-economic status and race on emergency hospital admission outcomes: Analysis from hospital admissions between 2001 and 2012

Socio-economic and racial/ethnic disparities in healthcare quality have been the point of huge discussion and debate. There is currently a public debate over healthcare legislation in the United States to eliminate the disparities in healthcare. We reviewed the literature and critically examined standard socio-economic and racial/ethnic measurement approaches. As a result of the literature review, we identified and discussed the limitations in existing quality assessment for identifying and addressing these disparities. The aim of this research was to investigate the difference between health outcomes based on patients' ability to pay and ethnic status during a single emergency admission. We conducted a multifactorial analysis using the 11-year admissions data from a single hospital to test the bias in short-term health outcomes for length of stay and death rate, based on 'payment type' and 'race', for emergency hospital admissions. Inconclusive findings for racial bias in outcomes may be influenced by different insurance and demographic profiles by race. As a result, we found that the Self-Pay (no insurance) category has the shortest statistically significant length of stay. While the differences between Medicare, Private and Government are not significant, Self-Pay was significantly shorter. That 'Whites' have more Medicare (older) patients than 'Blacks' might possibly lead to a longer length of stay and higher death rate for the group.

Clinical, histopathologic and molecular features of idiopathic and diabetic nodular mesangial sclerosis in humans

BACKGROUND

Idiopathic nodular mesangial sclerosis, also called idiopathic nodular glomerulosclerosis (ING), is a rare clinical entity with an unclear pathogenesis. The hallmark of this disease is the presence of nodular mesangial sclerosis on histology without clinical evidence of diabetes mellitus or other predisposing diagnoses. To achieve insights into its pathogenesis, we queried the clinical, histopathologic and transcriptomic features of ING and nodular diabetic nephropathy (DN).

METHODS

All renal biopsy reports accessioned at Indiana University Health from 2001 to 2016 were reviewed to identify 48 ING cases. Clinical and histopathologic features were compared between individuals with ING and DN (n = 751). Glomeruli of ING (n = 5), DN (n = 18) and reference (REF) nephrectomy (n = 9) samples were isolated by laser microdissection and RNA was sequenced. Immunohistochemistry of proline-rich 36 (PRR36) protein was performed.

RESULTS

ING subjects were frequently hypertensive (95.8%) with a smoking history (66.7%). ING subjects were older, had lower proteinuria and had less hyaline arteriolosclerosis than DN subjects. Butanoate metabolism was an enriched pathway in ING samples compared with either REF or DN samples. The top differentially expressed gene, PRR36, had increased expression in glomeruli 248-fold [false discovery rate (FDR) P = 5.93 × 10-6] compared with the REF and increased 109-fold (FDR P = 1.85 × 10-6) compared with DN samples. Immunohistochemistry revealed a reduced proportion of cells with perinuclear reaction in ING samples as compared to DN.

CONCLUSIONS

Despite similar clinical and histopathologic characteristics in ING and DN, the uncovered transcriptomic signature suggests that ING has distinct molecular features from nodular DN. Further study is warranted to understand these relationships.

Late pancreatic panniculitis in a simultaneous pancreas kidney transplant patient with failed allografts

We present a rare case of pancreatic panniculitis in a 59-year-old male simultaneous pancreas-kidney (SPK) recipient with failed allografts. The patient presented with fever and painful erythematous nodules on his leg 1 month after stopping all immunosuppression. A thorough infectious and rheumatological workup was negative. He had pancreas rejection 4 years after SKP transplant and was restarted on dialysis after 14 years when his renal allograft failed due to chronic allograft nephropathy. His chronic immunosuppression (tacrolimus, azathioprine) was stopped and prednisone was weaned over 3 months at that time. A skin biopsy revealed saponification of the subcutaneous fat with inflammation pathognomonic of pancreatic panniculitis. Concurrent allograft pancreatitis confirmed with elevated lipase and a computed tomography scan finding of peripancreatic graft stranding and atrophic native pancreas. He was started on pulse steroid therapy for 3 days followed by oral taper. This resulted in dramatic resolution of all skin lesions and normalization of lipase levels within 1 week, followed by resumption of low-dose tacrolimus and azathioprine. This is an extremely rare occurrence of panniculitis in pancreas allograft after 10 years of pancreatic failure associated with stopping immunosuppression.

Impact of Sleep Telemedicine Protocol in Management of Sleep Apnea: A 5-Year VA Experience

BACKGROUND

There is growing evidence that demonstrates an important role for telemedicine technologies in enhancing healthcare delivery. A comprehensive sleep telemedicine protocol was implemented at the Veterans Administration Medical Center (VAMC), Milwaukee, WI, in 2008 in an effort to improve access to sleep specialty care. The telemedicine protocol relied heavily on sleep specialist interventions based on chart review (electronic consult [e-consult]). This was done in response to long wait time for sleep clinic visits as well as delayed sleep study appointments. Since 2008 all consults are screened by sleep service to determine the next step in intervention. Based on chart review, the following steps are undertaken: (1) eligibility for portable versus in-lab sleep study is determined, and a sleep study order is placed accordingly, (2) positive airway pressure (PAP) therapy is prescribed for confirmed sleep apnea, and (3) need for in-person evaluation in the sleep clinic is determined, and the visit is scheduled. This study summarizes the 5-year trend in various aspects of access to sleep care after implementation of sleep telemedicine protocol at the Milwaukee VAMC.

PATIENTS AND METHODS

This is a retrospective system efficiency study. The electronic medical record was interrogated 5 years after starting the sleep telemedicine protocol to study annual trends in the following outcomes: (1) interval between sleep consult and prescription of PAP equipment, (2) total sleep consults, and (3) sleep clinic wait time.

RESULTS

Two part-time sleep physicians provided sleep-related care at the Milwaukee VAMC between 2008 and 2012. During this period, the interval between sleep consult and PAP prescription decreased from ≥60 days to ≤7 days. This occurred in spite of an increase in total sleep consults and sleep studies. There was also a significant increase in data downloads, indicating overall improved follow-up. There was no change in clinic wait time of ≥60 days.

CONCLUSIONS

Implementation of a sleep telemedicine protocol at the Milwaukee VAMC was associated with increased efficiency of sleep services. Timeliness of sleep management interventions for sleep apnea improved in spite of the increased volume of service.

Wireless remote patient monitoring in older adults

Wireless patient monitoring systems are emerging as a low cost, reliable and accurate way of healthcare delivery. In this paper we present a wireless remote vital sign monitoring system with audio/video data transmission. Vital signs include; blood pressure (systolic and diastolic), heart rate, pulse, oxygen saturation, body temperature, lungs air volume and blood glucose level. In addition, a two-way audio/video communication link connects patients to their healthcare providers. The proposed system employs a computer-based software application that effectively incorporates current data with electronic medical record in order to enhance patient care. We evaluated this system with 10 individuals for assessing its acceptability by the users and its compatibility with other medical devices. A clinical trial with more than 30 participants aged over 65 years is also in progress at a local hospital.

A case of Creutzfeldt-Jakob disease: diagnostic dilemmas of a rapidly fatal disease

Creutzfeldt-Jakob disease (CJD) is a rapidly progressive and ultimately fatal disorder of the central nervous system. It occurs worldwide with an incidence of 0.5-1 new case per million population per year. No specific treatment is available and management is limited to supportive care. Autopsy or biopsy provides a definitive diagnosis. Because of the transmissible nature of the disease and hesitancy of patients/family members to give consent for biopsy, numerous challenges in confirming the clinical diagnosis are faced by healthcare professionals. We report a case of 66-year-old male who was hospitalized due to hip fracture following a fall. Acute mental status changes followed the surgical fixation of hip fracture which triggered neurologic work up. This finally revealed suspicion and confirmation of CJD. Patient had progressive cognitive decline with akinetic mutism during further hospital stay and was later discharged home with hospice. Shorter thereafter he died at home. This case demonstrates the importance of keeping an open mind towards possibility of CJD when faced with esoteric neurologic presentations. Also this case provides insight into challenges in quarantine and sterilization of surgical instruments when these patients go through major surgeries.

Mitochondrial DNA diversity in tribal and caste groups of Maharashtra (India) and its implication on their genetic origins

Genetic relationships among caste-groups are not uniform across the geographical regions of India. Many anthropologists have speculated on the tribal origin of some caste groups in Maharashtra and other states of India. To test this hypothesis, we used neutral mtDNA markers to study genetic relatedness among tribal and caste groups from Maharashtra. Descriptive statistics such as nucleotide diversity, gene diversity and average mismatches were found to be of the same magnitude. Phylogenetic network analysis exhibited a star-like expansion that may date back to the peopling of Eurasia, approximately 50,000 year ago. The reconstruction of mtDNA haplogroups showed that both the caste and tribal populations share similar branches of the tree. Also, the coalescence age estimation of caste and tribal populations suggests the persistence of maternal lineages with their root in early late Pleistocene. Our mtDNA analyses show some preliminary and significant evidence for the origin of prehistoric tribal and hierarchical caste societies of Maharashtra.

Curcumin prevents intravesical tumor implantation of the MBT-2 tumor cell line in C3H mice

PURPOSE

The development of an effective nontoxic intravesical agent that may be used immediately after bladder tumor resection to prevent the implantation of tumor cells would be a significant clinical advancement. We report the cytotoxic effects of curcumin on bladder tumor cell lines as well as its effects on the intravesical implantation of tumor cells in C3H mice.

MATERIALS AND METHODS

UMUC human and MBT-2 mouse bladder cancer lines were incubated with 0 to 100 microM. curcumin in dimethyl sulfoxide for 30 minutes and cell viability was determined by clonal assay. Additional culture dishes were incubated with curcumin and processed for electron microscopy. Using the C3H mice and the MBT2 tumor lines the effects of intravesical curcumin on tumor implantation after bladder injury was studied. The 10 group 1 mice served as nontreatment controls. In the 18 group 2 mice 30 minutes after tumor cell implantation 100 microM. curcumin in 0.1% dimethyl sulfoxide were instilled intravesically for 30 minutes. The 15 group 3 mice served as treatment controls with 0.1% dimethyl sulfoxide or culture medium instilled intravesically for 30 minutes. Animals were sacrificed 7 to 10 days after treatment and the bladder was subjected to histological analysis for tumor.

RESULTS

At the 100 microM. dose curcumin was completely lethal to the 2 cell lines on clonal growth assay. Electron microscopy revealed apoptotic bodies after curcumin administration. The tumor implantation rate was 16.7% (3 of 18 mice) in curcumin treated bladders and 73% (11 of 15) in the vehicle control group.

CONCLUSIONS

At the 100 microm. concentration curcumin is a potent cytotoxic agent against the MBT and UMUC bladder tumor cell lines. In addition, curcumin effectively inhibits tumor implantation and growth in this murine bladder tumor model.

Activation of creatine kinase-B and phospholamban gene expression in transformed latissimus dorsi muscle: evaluation of mRNA by polymerase chain reaction

Latissimus dorsi muscle (LDM) transformation following chronic stimulation is the critical requirement for its use in cardiac assist procedures. In order to identify one or two molecular markers that can be used to effectively monitor the LDM transformation, the modulation in the expression of creatine kinase (CK) and phospholamban (PLB) genes by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was examined. Continuous in situ stimulation of left LDM was performed in four dogs for a period of 10 weeks after a vascular delay period of 2 weeks following surgery. For RT-PCR, gene-specific radiolabeled primers and equal amounts of cDNA synthesized from total RNA extracted from the LDM biopsies obtained at 4, 7, and 10 weeks of stimulation were used. A 2.6-fold increase in creatine kinase (brain type) (CK-B) mRNA was observed at transformed LDM compared to the control (P = 0.004) following 10 weeks of stimulation. On the contrary, a 30% decline was observed in creatine kinase (muscle type) (CK-M) mRNA level. An increase up to eight-fold was also observed in PLB mRNA in stimulated LDM compared to the contralateral muscle (P = 0.002). The PLB mRNA level in transformed LDM reached plateau and became comparable to that of normal heart after 7 weeks of stimulation. However, a sustained increase in CK-B mRNA level was observed until 10 weeks of stimulation. The level of beta-actin mRNA used as control remained the same in both stimulated and control samples. Thus the increase in CK-B and PLB mRNA and downregulation of CK-M mRNA in transformed LDM, demonstrated here by RT-PCR, indicate a switch from anaerobic to aerobic potential of transformed LDM along with a change towards slow-twitch phenotype and provide valuable markers to monitor the effectiveness of muscle transformation in cardiomyoplasty.

Inhibition by retinoic acid of type IV collagenolysis and invasion through reconstituted basement membrane by metastatic rat mammary adenocarcinoma cells

The activity of type IV collagenase, which enables tumor cells to degrade collagen type IV found in the subendothelial basement membrane, has been correlated with the metastatic potential in several tumor types, including the rat 13762NF mammary adenocarcinoma cell line and its clones. In this study, we examined whether all-trans-retinoic acid (all-trans-RA) and other retinoids, which exhibit antitumor activity in vitro and in vivo, affect the collagenolytic activity of metastatic rat 13762NF mammary adenocarcinoma cells. Cells of the highly metastatic lung-colonizing clone MTF7.T35.3, derived from the 13762NF cell line, were treated for 3 days with 0.1, 1, or 10 microM all-trans-RA, harvested, and seeded on [3H]proline-labeled extracellular matrix deposited by cultured rat lung endothelial cells or on a film of purified [3H]proline-labeled type IV collagen. The amount of radioactivity released into the medium during the subsequent 24 to 72 h was measured, and it was found that all-trans-RA treatment inhibited degradation of extracellular matrix and type IV collagen by 50 to 60%. This effect was observed whether the cells had been treated with all-trans-RA in serum-free medium or in medium supplemented with heat-inactivated or acid-treated fetal bovine serum. The growth of the cells was not inhibited under these conditions, except after treatment with 10 microM all-trans-RA in serum-free medium. The reduction in collagenolytic activity was observed in viable cells as well as in conditioned medium. A 24-h exposure of cells to all-trans-RA was sufficient to cause a 30% decrease in the collagenolytic activity, and this inhibitory effect was reversible. The direct addition of all-trans-RA to conditioned medium had no effect on secreted collagenase activity. The apparent molecular weights of the collagenolytic enzymes were determined by electrophoresis of cell extracts and concentrated conditioned medium in type IV collagen-embedded polyacrylamide gels followed by renaturation and activation of the enzymes within the gels. Two major type IV collagenolytic metalloproteinases exhibiting molecular weights of 64,000 and 88,000, respectively, were detected by this method. These two enzymes were also found to have specificity for gelatin. The Mr 64,000 enzyme could be extracted from viable cells (presumably from the cell membrane) by 2% 1-butanol. Treatment with all-trans-RA decreased the level of these enzymes in the cellular, cell membrane, and conditioned medium compartments.(ABSTRACT TRUNCATED AT 400 WORDS)

Methanol production from the degradation of pectin by human colonic bacteria

When ingested, pectin can lower serum cholesterol levels in humans. Pectin is degraded by fecal bacteria in the colon. We examined the release of methanol (MeOH) by this degradation. A 0.2% glucose (2 g/L) mixture was used as the control medium. A pure culture of pectinolytic Erwinia carotovora was the control bacterium. The chief substrates were, in set 1, 0.2% pectin (2 g/L) and, in set 2, 0.1% glucose (1 g/L) and 0.1% pectin (1 g/L). Cultures of fecal bacteria and E carotovora grew for 72 h in each of the solutions. By 72 h the fecal flora culture in set 1 cleaved 30% of the possible methoxyl groups on pectin. The fecal flora in set 2 cleaved 90.7% of all possible methoxyl groups. Balance studies suggest that all of the free MeOH comes from methoxyl groups on pectin. This study demonstrates that fecal bacteria are capable of degrading pectin to release MeOH.

Diagnosis of tuberculosis by detection of mycobacterial antigen in pleural effusions and ascites

We describe a method for the diagnosis of pleural and peritoneal tuberculosis by the detection of tuberculous antigens using an enzyme-linked immunosorbent assay. Eleven tuberculous pleural fluid and 10 tuberculous ascitic fluid samples were studied by this technique, using 10 non-tuberculous pleural fluid and 14 non-tuberculous ascitic fluid samples as controls. An absorbance value of 0.3 was found to separate the tuberculous groups from their controls to a statistically significant extent (ascitic fluid P less than 0.05; pleural fluid P less than 0.01).

Unstirred water layers in rabbit intestine: effects of pectin

Pectins have been shown to affect the absorption of several different nutrients in clinical studies; however, the mechanisms for decreased absorption have not been defined. A possibility not studied with regards to pectin, but previously demonstrated to be important in absorption, is the effect of change in the unstirred water layer. As the unstirred water layer increases in thickness, the rate of absorption decreases for certain nutrients. The effect of pectin on the unstirred water layer in the lumen of rabbit jejunum was examined by previously described techniques. It was observed that: (1) increases in pectin concentration resulted in an increased thickness of the unstirred water layer; (2) for any stir rate, the addition of pectin increased the thickness of the unstirred water layer; and (3) stir rate is inversely related to the thickness of the unstirred water layer. It was concluded from these results that pectin increases the thickness of the unstirred water layer in rabbit jejunum. This mechanism may explain, in part, the reduction of the rate of absorption of certain nutrients seen following pectin ingestion.

Effect of dietary pectin on iron absorption and turnover in the rat

The influence of dietary pectin on iron absorption and retention was studied in rats. Basal diet with low and normal iron levels were fed with and without addition of 2% citrus pectin. After 40 days rats were fasted for 24 hours and were given 59Fe in dilute HCl with or without 2% pectin by gavage. Whole-body counting techniques were employed to monitor 59Fe absorption and turnover. Rats maintained on low iron diet absorbed and retained a much higher proportion of 59Fe than rats maintained on normal level of iron. Dietary pectin at the level fed in this study had no influence on iron uptake and/or turnover in rats.

Pectin: its interaction with serum lipoproteins

In vitro studies of interaction between grapefruit (Citrus paradisi) pectin and various human serum lipoproteins indicated that pectin interacts specifically with low-density lipoprotein. Examination of observed interaction between the pectin and low-density lipoprotein under variable experimental conditions revealed the electrostatic nature of this interaction. The results obtained from these studies suggest a possible biochemical basis by which dietary pectin may cause lowering of serum and/or tissue cholesterol levels.

Acid mucopolysaccharides of congenitally defective, rheumatic, and normal human aortic valves

The qualitative nature, total amount, and relative proportion of various acid mucopolysaccharides (AMPSs) found in congenitally defective (bicuspid), young rheumatic, and normal aortic valvular tissue were compared. No differences in the qualitative nature of AMPSs were found in any of the aortic tissues studies; hyaluronic acid, chondroitin sulfate B, and chondroitin sulfate A/C were the primary AMPS components, with a trace amount of heparin. Congenitally defective aortic valves showed increasing amounts of calcification, a lowering of total AMPS content, and an alteration in the relative proportions of various AMPS with advancing age, as compared with age-matched normal aortic valves. The total AMPS content of rheumatic aortic valves from individuals under the age of 21 years was found to be significantly higher than that of age-matched normal controls. In addition, these rheumatic aortic valves showed an alteration in AMPS composition that was similar to that of congenitally defective aortic valves obtained from older individuals. These observations suggest nonspecific changes in the AMPS composition caused by chronic tissue damage, calcification, and fibrosis.

Properties of extracellular neuraminidase produced by group A streptococcus

Extracellular neuraminidase production by group A streptococci was examined in 92 strains. Fourteen of these strains produced appreciable amounts of enzyme; 12 of the neuraminidase-producing strains belonged to T types 1, 4, and 12. Production of the enzyme paralleled bacterial growth in culture and was maximal in medium containing 0.2% glucose. The enzyme produced by one of these strains was partially purified by ammonium sulfate fractionation and filtration on G-200 Sephadex. Its molecular weight was estimated at 90,000. Activity was optimal at pH 5.7 and in the presence of 0.01 to 0.03 M calcium and magnesium cations. The enzyme was stable at temperatures of 4 and 37 degrees C for at least 24 h but was inactivated within 10 min at temperatures of 50 and 65 degrees C. The enzyme hydrolyzed 40% of the sialic acid in bovine submaxillary mucin, but was inactive on sialyl-lactose, porcine submaxillary mucin, oligosaccharides derived from porcine mucin, or human orosomucoid. The Km value for this enzyme with bovine submaxillary mucin as substrate was in the order of 3.6 x 10(-4) M.

Purification and chemical characterization of salt-extractable glycoproteins from porcine mitral valve

Four major glycoproteins were extracted by dilute salt solution from procine mitral valvular tissue. Two of these major glycoproteins, procine valve glycoprotein I and porcine valve glycoprotein III, were isolated and purified by fractionation of salt extract with ammonium sulfate followed by column chromatography on DEAE-cellulose. The purified glycoproteins appeared to be homogeneous by polyacrylamide disc electrophoresis in several buffer systems, and by Sephadex filtration. The porcine valve glycoprotein I has a molecular weight of approximately 120000. Isoelectric focusing yielded a single band, pI = 5.8. The glycoprotein contained large amounts of acidic amino acids, and amide nitrogen. The carbohydrate moiety was composed of fucose, mannose, galactose, glucose, glucosamine, and galactosamine in the molar ratio of 5:10:15:12:7:2 per mole of glycoprotein. The second major glycoprotein, porcine valve glycoprotein III, has an approximate molecular weight of 72000. This glycoprotein gives two bands upon analytical isoelectric focusing with isoelectric points of pI = 4.1 and 4.3. Porcine valve glycoprotein III contained large amounts of acidic amino acids and low amounts of amide nitrogen. Its carbohydrate moiety was composed of glucose, galactose, mannose, fucose, glucosamine, and sialic acid in the ratio of 3:3:2:1:4:1 mol/mole of glycoprotein. This glycoprotein was similar to a glycoprotein preparation isolated from porcine aortic intima by P.V. Wagh and B.I. Roberts (1972), Biochemistry 11, 4222.

Plasma membrane components of skin fibroblasts from normal individuals and patients with cystic fibrosis

Plasma membranes have been isolated without proteolytic modification from fibroblast lines derived from patients with CF, from heterozygous parents, and from normal children. The cells had been grown in the presence of 3H- OR 14C- labeled L-leucine, D-glucosamine, and L-fucose. Membranes were mixed in suitable combinations to allow comparisons to be made between the different cell types. No differences in the plasma membrane composition, as revealed by divergence in 3H- or 14C-profiles, could be detected after gel electrophoresis. Identical protein and glycoprotein components were present in approximately similar amounts in all groups of cells;

Comparative studies on the carbohydrate-containing membrane components of normal and adenosine 3':5'-cyclic monophosphate-treated Chinese hamster ovary cells

1. We investigated some of the changes in plasma-membrane composition that accompany the alteration in cell growth and morphology induced by treating Chinese-hamster ovary cells with dibutyryladenosine 3':5'-cyclic monophosphate (dibutyryl cyclic AMP). 2. A double-labelling technique was employed in which normal cells were given (14)C-labelled precursor, and those treated with dibutyryl cyclic AMP were given (3)H label. l-Leucine, d-glucosamine, and l-fucose were used to label the membranes. 3. After 3 days growth, the two populations of cells were harvested by trypsin treatment, the cells were pooled, and plasma membranes isolated. Proteins and glycoproteins of the membranes were separated by electrophoresis on sodium dodecyl sulphate-polyacrylamide gels, and the radioactive profiles for (14)C and (3)H and the staining patterns with Amido Black were compared. 4. Although certain components of the membrane from treated cells showed marked quantitative changes, there was neither major addition nor major deletions of components. 5. Complete proteolysis of the mixed membranes, of the material released from the cell surface by trypsin, and of the glycoproteins released from the cells into the medium, gave a series of radioactive glycopeptides when either fucose or glucosamine was employed as precursor. 6. After such glycopeptides were fractionated on columns of Sephadex G-50, marked differences in the elution profiles of (3)H and (14)C were noted. Dibutyryl cyclic AMP evidently causes alterations in the overall composition of the carbohydrate components of the cell surface. It was not possible to decide whether this was solely the result of the same glycoproteins being formed but in different proportions, or the result of modifications of oligosaccharide side chains on some of the glycoproteins. 7. Some of the changes were not unlike the reverse of those that accompany the transformation of fibroblasts by oncogenic viruses, and our results lend credence to the idea that the lowered amount of cyclic AMP noted in transformed cells is responsible for their altered surface properties.

L-ascorbic acid biosynthesis in higher plants from L-gulono-1, 4-lactone and L-galactono-1, 4-lactone

Detached bean (Phaseolus vulgaris) and strawberry (Fragaria) fruits fed l-gulono-1,4-lactone or l-galactono-1,4-lactone convert this compound, in part, to l-ascorbic acid. When l-galactono-1,4-lactone is given as a 0.25% solution to detached bean shoots, the ascorbic acid content is tripled in less than 10 hours. l-Gulono-1,4-lactone is only 5 to 10% as effective as its epimer. Experiments with specifically labeled l-gulono-1,4-lactone and l-galactono-1,4-lactone prove that conversion is direct. Ascorbic acid is labeled at the same carbon as its precursor.A method is described for preparation of l-galactono-1,4-lactone-2-(14)C from myo-inositol-2-(14)C. This method can be extended to the preparation of l-ascorbic acid-2-(14)C on the basis of results obtained in the present study.