Naturally occurring organosulfur compounds effectively inhibits PCSK-9 activity and restrict PCSK-9-LDL-receptor interaction via in-silico and in-vitro approach

The present study intended to divulge the potential role of garlic-derived organosulfur compounds (OSCs) in targeting PCSK-9 and averting its interaction with the EGF-A portion of LDL-R via in-vitro and in-silico analysis. Our in-silico screening data showed that 3-(Propylsulfinyl)-L-alanine (PSA), S-Ethyl-L-cysteine (SEC), alliin, and S-Allyl-L-cysteine (SAC) exhibited higher binding energy (-7.05, -7.00, -6.65, and -6.31 Kcal/mol, respectively) against PCSK-9, among other selected OSCs. Further, the protein-protein interaction study of PCSK-9-OSCs-complex with EGF-A demonstrated a similar binding pattern with E-total values ranging from -430.01 to -405.6 Kcal/mol. These results were further validated via in-vitro analysis which showed that SEC, SAC, and diallyl trisulphide (DAT) exhibited the lowest IC50 values of 4.70, 5.26, and 5.29 µg/mL, respectively. In conclusion, the presented data illustrated that SEC, SAC, and DAT were the best inhibitors of PCSK-9 activity and may have the potential to improve the LDL-R function and lower the circulatory LDL-C level.

Antioxidant, LC-MS Analysis, and Cholinesterase Inhibitory Potentials of Phoenix dactylifera Cultivar Khudari: An In Vitro Enzyme Kinetics and In Silico Study

We evaluated the therapeutic potentials of Khudari fruit pulp, a functional food and cultivar of Phoenix dactylifera, against neurological disorders. Our results demonstrate a good amount of phytochemicals (total phenolic content: 17.77 ± 8.21 µg GA/mg extract) with a high antioxidant potential of aqueous extract (DPPH assay IC50 = 235.84 ± 11.65 µg/mL) and FRAP value: 331.81 ± 4.56 µmol. Furthermore, the aqueous extract showed the marked inhibition of cell-free acetylcholinesterase (electric eel) with an IC50 value of 48.25 ± 2.04 µg/mL, and an enzyme inhibition kinetics study revealed that it exhibits mixed inhibition. Thereafter, we listed the 18 best-matched phytochemical compounds present in aqueous extract through LC/MS analysis. The computational study revealed that five out of eighteen predicted compounds can cross the BBB and exert considerable aqueous solubility. where 2-{5-[(1E)-3-methylbuta-1,3-dien-1-yl]-1H-indol-3-yl}ethanol (MDIE) indicates an acceptable LD50. value. A molecular docking study exhibited that the compounds occupied the key residues of acetylcholinesterase with ΔG range between -6.91 and -9.49 kcal/mol, where MDIE has ∆G: -8.67 kcal/mol, which was better than that of tacrine, ∆G: -8.25 kcal/mol. Molecular dynamics analyses of 100 ns supported the stability of the protein-ligand complexes analyzed through RMSD, RMSF, Rg, and SASA parameters. TRP_84 and GLY_442 are the most critical hydrophobic contacts for the complex, although GLU_199 is important for H-bonds. Prime/MM-GBSA showed that the protein-ligand complex formed a stable confirmation. These findings suggest that the aqueous extract of Khudari fruit pulp has significant antioxidant and acetylcholinesterase inhibition potentials, and its compound, MDIE, forms stably with confirmation with the target protein, though this fruit of Khudari dates can be a better functional food for the treatment of Alzheimer's disease. Further investigations are needed to fully understand the therapeutic role of this plant-based compound via in vivo study.

Pattern of third molar impactions in north-eastern peninsular Malaysia: A 10-year retrospective study

Background

Third molar impaction, if left untreated, has the potential to cause several complications. The evaluation of surgical difficulty of impacted third molar extraction aids in better formulation of treatment plan by minimizing surgical complications.

Objective

This study aimed to determine the prevalence of third molar impaction and related pathologic conditions in a cohort of patients living in North-eastern Peninsular Malaysia.

Methods

In this retrospective study, 490 orthopantomograms (OPGs) of patients who were referred to the Oral and Maxillofacial Surgery department between January 2010 and December 2019 were assessed. Data including age, gender, ethnicity, frequency of third molar impactions, their angulations and levels of eruption, retromolar space, and associated pathologic conditions were collected. Statistical analysis was performed using the Statistical Package for Social Sciences (SPSS) version 24.0. The significance level was set to P < 0.05.

Results

A total of 490 patients with a mean age of 28.87 years (range: 20-64) demonstrated 1957 impacted third molars (1022 mandibular + 935 maxillary). Impacted third molars were more likely present in females than males (1:2.20) (p < 0.05); and in Malay-ethnic (44.49%) patients followed by Chinese (34.45%) and Indians (21.02%). Mesioangular was the most common angulation of impaction both in the maxilla (24.68%) and mandible (18.34%). The most common pattern of third molar impaction was IIA (61.67%), and the retromolar space was significantly larger in males (13.6 mm; P < 0.05) than females (11.6 mm). The most frequently occurring pathological condition associated with third molars impaction is dental caries in the second or third molar (15.38%).

Conclusions

This study highlights mesioangular impaction with their occlusal plane at the same level as the occlusal plane of the adjacent tooth being the most prevalent pattern of third molar impaction in North-eastern Peninsular Malaysia.

100 Years of the Journal of Dental Research: A Bibliometric Analysis

Since its inception in 1919, the Journal of Dental Research has continually published high-quality articles that span the breadth of research topics relevant to dentistry, oral surgery, and medicine. As part of the journal’s centennial celebration, we conducted an electronic search on Scopus to identify and analyze the top 100 most cited articles from 1919 to 2018. Since Scopus does not capture older citations, we conducted an additional analysis by Google Scholar to identify key articles published in the first 50 y of the journal. Based on Scopus, the articles were ranked in descending order per their citation counts. The citation counts of the 100 most cited articles varied from 262 to 1,503. The year in which the largest number of top 100 articles were published was 2004 ( n = 6). Within the top 100, the majority of articles originated from the United States ( n = 52). Research Reports–Biomaterials & Bioengineering was the most frequent category of cited articles ( n = 35). There was no significant association between total citation count and time since publication (correlation coefficient = –0.051, P = 0.656). However, there was a significant negative association of citation density (correlation coefficient = –0.610, P < 0.01) with time since publication. Our analyses demonstrate the broad reach of the journal and the dynamics in citation patterns and research agenda over its 100-y history. There is considerable evidence of the high variance in research output, when measured via citations, across the globe. Moreover, it remains unclear how patients’ priorities and dental health care needs are aligned with the perceived influence of single research pieces identified by our search. Our findings may help to inspire future research in tackling these inequalities and highlight the need for conceptualizing research priorities.

Therapeutic efficacy of Boerhaavia diffusa (Linn.) root methanolic extract in attenuating streptozotocin-induced diabetes, diabetes-linked hyperlipidemia and oxidative-stress in rats

Introduction: We have previously demonstrated that sequentially extracted methanolic fractions of Boerhaavia diffusa (Linn.) showed marked antioxidant, antidiabetic and oxidative-DNA damage protective properties in vitro. The present study was undertaken to evaluate the beneficial effects of B.diffusa (Linn.) methanolic root extract and its partially purified bioactive fraction on streptozotocin (STZ)-induced hyperglycemia and hyperlipidemia in rats. Methods: The diabetic rats were treated for fourteen weeks either with methanolic extract of B. diffusa root (D-MT1, D-MT2, and D-MT3 : doses of 50, 150, and 300 mg/rat/day, respectively), partially isolated bioactive fraction (DBT: 0.5 mg/rat/day), or glibenclamide (D-GT: 0.5 mg/rat/day). Results: The level of fasting blood glucose (FBG) and glycated hemoglobin (HbA1c) were significantly alleviated in D-MT- and D-BT treated groups after fourteen weeks of administration. Moreover, plasma lipid profile, free fatty acids (FFAs), phospholipids (PLs), HMG-CoA reductase (HMG-R) activity, conjugated diene (CD), lipid hydroperoxide (LOOH), and malondialdehyde (MDA) were also markedly ameliorate d in all treatment groups. In addition, the activity of antioxidant enzymes, e.g., superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (Gred), and glutathione-S-transferase (GST), were also significantly restored by D-MT — and D-BT — treated groups. Furthermore, histologically, all the unseemly features of nephropathy were extensively regressed and normalized by the administration of B. diffusa and its bioactive fraction. Conclusions: Our results demonstrate a strong antidiabetic and hypolipidemic impact of B. diffusa extract an ideal alternative therapeutic agent in the prevention and treatment of diabetes as well as diabetes-linked hyperlipidemia.  

Effect of Tumor Size and p16 Status on Treatment Outcomes - Achievement of Complete Remission in Prospectively Followed Patients with Oropharyngeal Tumors

BACKGROUND

Oropharyngeal squamous cell tumors associated with human papillomavirus infection (p16 positive tumors) have better prognosis than p16 negative tumors regardless of the more advanced stage of the disease. Tumor volume (GTVt+n) is generally an important factor affecting treatment results of ionizing radiation. The aim of this prospective non-randomized study is to evaluate the effect of tumor volume on the (chemo)radiation treatment results in a group of patients with p16 negative and p16 positive oropharyngeal tumors.

PATIENTS AND METHODS

Patients with confirmed squamous cell tumor of the oropharynx of stages III and IV, according to the 7th version of the TNM (tumor-nodes-metastases) classification, were eligible for this study. The main exclusion criteria were palliative treatment, neoadjuvant chemotherapy or planned concomitant therapy with cetuximab. Patients were treated according to standardized protocols with curative intent. Primary tumor volume (GTVt) and involved nodes volume (GTVn) were obtained from radiotherapy planning system for further statistical analysis. The differences in tumor volumes between the groups according to p16 expression were assessed with subsequent testing of probability to achieve complete remission (CR) of the disease in both groups.

RESULTS

In total, 49 patients - 84% men, median age 60.5 years, 25 (51%) patients p16 positive, 40 (82%) underwent concomitant chemoradiotherapy. Median of GTVt in the whole patients group is 40.2 ccm, GTVn 11.78 ccm and median volume of the whole tumor burden (GTVt+n) 70.21 ccm (range 11.05-249). Median of GTVn was greater in the p16 positive cohort (p = 0.041). In the entire group, the median time to reach CR was 91 days (95% CI 86-107 days) from the end of radiotherapy. In the group of p16 negative patients, 14 achieved CR (61%) out of 23 patients, in p16 positive group 20 (80%) out of 25 patients (p = 0.111). P16 negative patients had a longer time to CR (p = 0.196, HR 1.58, 95% CI 0.79-3.18). None of the independently assessed volumetric parameters of the tumor (GTVt, GTVn, GTVt+n) affected CR in the p16 positive patients group, while there was a significant impact of the whole tumor burden (GTVt+n) in the p16 negative cohort (median 58.1 ccm in CR patients vs. 101.9 ccm, p = 0.018).

CONCLUSION

We have showed less GTVt+n dependence to achieve CR in p16 positive tumors in comparison with p16 negative tumors. Thus, p16 positive oropharyngeal squamous cell cancers should not be withdrawn from the curative treatment intent based on the greater GTVt+n. Key words oropharyngeal neoplasms - p16 status - treatment outcome - tumor burden - complete remission This work was supported by grant of the Ministry of Health of the Czech Republic AZV 15-31627A and by grant of the Ministry of Health of the Czech Republic - Conceptual development of a research organization (MMCI 00209805). The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 2. 11. 2018 Accepted: 11. 11. 2018.

[MicroRNAs in Prediction of Response to Radiotherapy in Head and Neck Cancer Patients - Pilot Study]

BACKGROUND

Radiotherapy plays a key role in the treatment of squamous cell head and neck cancers (HNSCC). The effectivity of radiation therapy is often limited by radioresistance of these tumours. microRNAs (miRNAs) are endogenous, evolutionary conserved, small non-coding RNAs involved in regulation of cellular processes associated with radioresistance. The objective of this study was to identify miRNA profile enabling to predict the radiation treatment outcomes in HNSCC patients.

MATERIAL AND METHODS

The retrospective study included HNSCC patients who underwent a definitive radiotherapy. Patients were divided into two groups according to loco-regional control (LRC) as follows - short LRC (n = 22; median 5.1 months (min. 1.3, max, 18.6)) vs. long LRC (n = 21; 60.4 (min. 46.8, max. 98.8)) group. Global miRNA expression profiles were obtained by use of Affymetrix microarray technology (GeneChip miRNA 4.0 Array).

RESULTS

We identified 24 miRNAs to be significantly associated with LRC (p < 0.05), all of these miRNAs were upregulated in patients with short LRC. Out of these miRNAs, 12 miRNAs with p < 0.025 and 4 miRNAs with p < 0.01 have been identified.

CONCLUSION

miRNAs seems to be promising as potential biomarkers predicting radiotherapy treatment outcomes in patients with HNSCC.Key words: microRNAs - radiotherapy - head and neck cancer The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Supported by Ministry of Health of the Czech Republic, grant No. 15-31627A. All rights reserved.Submitted: 19. 3. 2018Accepted: 20. 3. 2018.

Helminthic infestation in children of Kupwara district: a prospective study

The present study deals with the investigation of the frequency of intestinal helminth parasites in children of Kupwara, Kashmir, India. Three hundred and twelve children in the age group of 4-15 years were examined for different intestinal helminths in three schools located in rural areas. Two hundred and twenty two of 312 (71.15%) tested positive for various intestinal helminths. The various helminth parasites included Ascaris lumbricoides , Trichuris trichiura , Enterobius vermicularis and Taenia saginata . By far, the highest frequency of 69.23% (216/312) was noted for Ascaris lumbricoides followed by Trichuris trichiura 30.76% (96/312), Enterobius vermicularis 7.69% (24/312) and Taenia saginata 7.69% (24/312). Single infection was found in 33.65% (105/312) and mixed infection was seen in 37.5% (117/312) children. This study emphasizes the need for improved environmental conditions, i.e., clean water supplies, enhanced sanitation and chemotherapy of school-age children in rural areas.

Impact of sedation and resident teaching on complications of colonoscopy

There is controversy regarding the frequency of sedation-related complications of colonoscopies and whether these procedures are safely performed by physicians-in-training. We retrospectively reviewed the safety of 1,004 consecutive outpatient colonoscopies. No perforations occurred. No patients were hospitalized for sedation-related complications. Seventeen percent of patients had significant changes in vital signs that lasted less than 5 min. These changes were less common in patients receiving </=3 mg midazolam intravenously without meperidine (p < 0.005). Complications were slightly more frequent in procedures performed by trainees (23%) than by gastroenterologists (12%) and by surgeons (18%) (p = 0.01). These data support the safety of colonoscopy under intravenous sedation, even when performed by trainees.

Iron deficiency anaemia: continuous versus intermittent treatment in anaemic children

Iron deficiency anaemia is a common disorder among paediatric population. Traditionally, oral iron is given for treatment on daily basis. We undertook this study to compare the results of intermittent with continuous oral iron therapy in children. The study was conducted at Combined Military Hospital (CMH), Lahore. Children (aged 1 to 6) with iron deficiency anaemia (Hb 11 g/dl) were allocated at random into two groups, A (n = 27) and B (n = 28). The mean Hb of group A, before treatment, was 8.56 (+/- 1.51) g/dl and that of group B was 8.32 (+/- 1.68) g/dl. Group A was given daily oral dosage of 6 mg/kg of elementAL iron whereas group B was given the same dosage of iron but only 3 days a week. After 2 months of treatment the Hb of group A rose to a mean of 11.06 (+/- 0.72) g/dl and that of group B was increased to 11.3 (+/- 0.90) g/dl, respectively. The difference, in the rise of Hb of two groups, was not statistically significant. It was concluded that in our sample of population, the results of intermittent and continuous oral iron therapy, for iron deficiency anaemia in children aged 1 to 6 years, were identical.

A numerical investigation of the mechanics of swelling-type intramedullary hip implants

The novel concept of swelling-type intramedullary hip implants that attain self-fixation by an expansion-fit mechanism resulting from controlled swelling of the implant (by absorption of body fluids) was examined in detail using a finite element model of the implant-femur system. Some of the potential advantages of this technique over traditional techniques include enhanced fixation, lower relative micromotions, improved bony ingrowth, and elimination of acrylic cement. The finite element model created in this study incorporated: (i) the major aspects of the three-dimensional geometry of the implant and femur, (ii) the anisotropic elastic properties of bone and implant materials and the changes in orientation of the principal axes of anisotropy along the length of the implant-femur system, (iii) a layer of cancellous bone between the implant and cortical bone in the proximal femoral region, and (iv) frictional sliding between the bone and implant. The model was used to study quantitatively the parametric influence of various material design variables on the micromotions and stress fields in the bone-swelling-type implant system. The results of the finite element analyses were used to establish material behavior goals and provide targets for a material development study.

Prognostic factors influencing mortality in meningococcal meningitis

The clinical features and some laboratory parameters of 247 cases of meningococcal meningitis admitted between January 1983 and April 1990 to a paediatric ward in Jawahar Lal Nehru Medical College Hospital, India were analyzed retrospectively. A total of 189 (76.5%) were more than 5 years of age. The maximum number of cases occurred between October and April each year. Complications included bleeding tendencies, neurological deficits, gangrene of limbs, arthritis, uveitis and cataract. The overall mortality rate was 16%. A scoring system based on some clinical characteristics correctly predicted a fatal outcome in all but three children.

C-reactive protein in CNS infection

Serum and CSF levels of CRP were measured by radial immunoassay in 99 subjects consisting of 20 controls, 34 pyogenic meningitis (PM), 21 tuberculous meningitis (TBM) and 24 viral encephalitis (VE). There was significant difference in the CRP levels (p less than 0.01) depending on the type of disease in both serum and CSF. The initial serum and CSF levels of CRP in patients with TBM was intermediate between those of PM and VE and were found to be significantly (p less than 0.001) low when compared with three days post treatment levels in children with PM. Both serum and CSF-CRP levels were significantly high (p less than 0.001) in patients succumbing to death than those who survived. Measurement of CRP in serum and CSF is a useful parameter in differentiating partially treated PM from TBM.

Use of flagellin-enriched antigens in a rapid, simple and specific quantitative enzyme immunoassay for Lyme disease antibodies in human serum samples

An enzyme immunoassay (EIA, ELISA) using microwells coated with a flagellin-enriched fraction of B. burgdorferi and absorbent-containing sample diluent for the quantitative determination of Lyme disease (LD) IgG and IgM antibodies in human serum samples was described. This LD EIA required three 15-minute incubations at room temperature, followed by a 1-step normalization of photometer readings to EIA units (EU/ml). Compared with tests using the whole bacterial extract as antigens and a sample diluent containing 6% BSA, this new LD EIA revealed lower values for 20 syphilis (SS) and 21 normal serum samples (NS) but about the same for 21 Lyme disease (LD) samples, allowing lower cut-off points which would place almost all these SS and NS samples below while almost all LD samples above the positive cut-off point. The LD EIA results of larger numbers (67 to 291) of mixed samples correlated with results of four reference EIA. However, the LD EIA gave lower (2 to 4 fold) reactivities (index values) with SS and NS samples but higher values with positive serum samples than reference EIA. Thus, this LD EIA showed improvements in both specificity and sensitivity over other tests compared.

Increased oxidative metabolism in phytohemagglutinin-stimulated lymphocytes from patients with systemic lupus erythematosus is associated with serum SSA antibody

We have examined oxidative metabolism in phytohemagglutinin (PHA)-stimulated lymphocytes from patients with systemic lupus erythematosus (SLE) because increased oxygen free radicals would explain the DNA abnormality previously observed in these cells. Almost no oxidative activity was found in freshly isolated control or lupus lymphocytes or control lymphocytes stimulated with PHA. However, increased oxidative metabolism, measured by nitroblue tetrazolium (NBT) conversion to formazan, was found in PHA-stimulated lymphocytes from 14 of 21 lupus patients. A time course study showed that NBT activity appeared in positive lupus lymphocytes at 1-2 days of PHA stimulation, increased to a maximum at 2-4 days, and diminished thereafter. NBT activity was not related to specific disease symptoms, drug therapy, or serum dsDNA, Sm, RNP, or SSB (La) antibodies. The selected population of lupus patients studied precluded conclusions about NBT activity and disease severity. However, the intensity of NBT response in stimulated lupus lymphocytes was positively correlated with the presence of serum SSA (Ro) antibody. We suggest that increased oxidative activity of SLE lymphocytes generates a chemical change in endogenous DNA in vivo and may be a primary event in the pathogenesis of autoimmunity. Absence of detectable oxidative activity in stimulated lymphocytes in a subgroup of lupus patients suggests that at least two different mechanisms are associated with the altered DNA profiles observed in this disorder.

Circulating immune complexes in tuberculosis--an indicator of activity

Circulating immune complexes (CIC) were assayed in 100 cases of tuberculosis and 30 age matched control children. The estimation was done by PEG assay before the commencement of antitubercular therapy. CIC were present in only 3.3% of the control children as compared to 68% of children with tuberculosis. The presence of CIC was observed to vary with the type of tuberculosis. The percentage positivity was highest (100%) in children with miliary tuberculosis. Subsequent estimation of CIC done after one and three months of antitubercular therapy showed a marked decrease in the percentage of positive cases (6.1 and zero percent respectively).

Prognostic value of 'C' reactive protein in tuberculosis

'C' reactive protein (CRP) levels were determined in 100 cases of tuberculosis and 30 age and sex matched children. Serial estimations, one and 3 to 6 months after initiation of therapy was done in 81 and 41 of these patients, respectively. Mean initial levels of CRP in tuberculosis group was 18.52 micrograms/ml while in the control group it was 2.77 micrograms/ml (p less than 0.001). The elevated CRP levels fell significantly to 5.93 micrograms/ml after one month of treatment (p less than 0.001) and by 3 to 6 months of treatment had fallen to normal values. The fall in CRP levels correlated with clinical response. It is concluded that CRP can serve as a sensitive indicator of activity of the disease and the return to normal values of initially elevated CRP levels may indicate a good therapeutic response.

Cell-mediated immune responses in malnourished host

One hundred children in the age group 6 months to 5 years were investigated for cell-mediated immune response in relation to their nutrition. The nutritional status was assessed by the Wellcome classification. The majority (54 per cent) of children had marasmus. Absolute lymphocyte count was found to be significantly low (P less than 0.01) in all malnourished groups except in mild forms of undernutrition. Small lymphocytes were also found to be significantly decreased (P less than 0.001) in malnourished children. A significant depression (P less than 0.001) was observed in the percentage and absolute T cells in all the malnourished children with kwashiorkor who showed the maximum depression of counts. All the control children showed DNCB skin reactions above grade 2+ while only 39 per cent of malnourished children showed reaction of this grade. After 4-6 weeks of dietary therapy, T cell counts were comparable with control values and DNCB skin test returned to normal in more than 75 per cent of cases.

Phagocyte metabolic functions in iron deficiency anaemia of Indian children

Nitroblue tetrazolium test (NBT) and bactericidal activity of polymorphonuclear leucocytes was studied in 40 patients with iron deficiency anaemia (aged 0-12 years). NBT test had a significant correlation with serum iron (P less than 0.001) in all cases of iron deficiency anemia. Haemoglobin levels less than 4 g/dl also correlated significantly with NBT score. Bactericidal activity with opsonin-coated Staphylococcus aureus was considerably decreased in severe anaemia, but no significant correlation was found with serum iron concentration (P less than 0.1). The phagocytic and bactericidal activity of polymorphonuclear leucocytes is dependent upon serum iron levels and is considerably reduced in iron deficient state in anaemic children.

Blood-Pb and hair-Pb levels in donor-matched samples

Lead concentrations in blood and scalp hair of 200 school boys, aged 6-8 years, were measured by electrothermal atomic absorption spectrometry. The mean blood-Pb concentration was 6.8 microg dl(-1) and the mean hair-Pb concentration was 9.7 microg g(-1) (dry weight). These values are well within the normal range for the respective tissues, indicating that the children studied are presently at relatively low risk from environmental lead pollution. A correlation analysis carried out on the data failed to show any statistically significant correlation (r = 0.13, p < 0.05) between the blood-Pb and hair-Pb concentrations.

Role of phospholipids in the DDT-induced efflux of potassium in human erythrocytes

Incubation of human erythrocytes for 1-2 h at 37 degrees C in a suspension of dipalmitoylphosphatidylcholine (DDPC) liposomes results in a phospholipid enrichment of erythrocyte membranes by 45-55% and a depletion of cholesterol by 19-24%. The enrichment by DPPC was time and concentration dependent. By contrast, dioleoylphosphatidylcholine (DOPC) liposomes were less effective in enriching the membranes with phospholipid and in depleting the membranes of cholesterol. Concomitantly, the DDT-induced efflux of K+ was reduced in the case of DPPC-enriched erythrocytes but enhanced in DOPC-enriched erythrocytes. These results suggest that DDT partitions more readily into the unsaturated than the saturated phospholipids of the erythrocyte membrane. It is concluded that the extent to which DDT affects the flux of K+ across the membrane is dependent on the fluidity of the lipid phase. We also report here a rapid method for cholesterol depletion of red blood cells in comparison to previously reported methods.

Effect of allyl isothiocyanate on plasma and urinary concentrations of some biochemical entities in the rat

Allyl isothiocyanate (AITC) is a constituent of several plants of the family Cruciferae that are commonly used as food. This study investigated the effect of feeding AITC to male Sprague-Dawley rats on their plasma glucose and uric acid levels as well as on the urinary concentrations of glucose, 17-ketosteroids (17-KS), creatinine, and uric acid. Other test compounds included were thyroxine (T4) and thiouracil (TU). AITC caused a highly significant (P smaller than or equal to 0.01) depression in the plasma glucose and uric acid levels compared with the control. TU caused a significant depression only of the plasma glucose. T4, on the other hand, significantly increased the levels of both glucose and uric acid. The AITC-treated rats voided twice as much urine as the controls or those receiving TU or injected with T4. The 24-h excretion of glucose, uric acid, and creatinine was significantly (P smaller than or equal to 0.01) higher in animals fed AITC than in those consuming the control diet, while the excretion of 17-KS was significantly lower. Results on an equal urine volume basis showed that differences in the excretion of glucose and creatinine were related to differences in the urine volume. TU significantly depressed excretion of all the compounds but glucose. The effect of T4 on the excretion of 17-KS and uric acid resembled that of AITC and TU, thus showing that these compounds depressed the androgenic function of the animal.

A study of the chemical binding of allyl isothiocyanate with thyroxine and of the effect of allyl isothiocyanate on lipid metabolism in the rat

Two experiments were conducted with allyl isothiocyanate (AITC): one in vitro, to investigate the chemical binding of AITC with thyroxine (T4), tyrosine (Tyr), and leucine (Leu), and the other in vivo, to evaluate the effect of AITC on the blood clotting mechanism and on the protein and lipid contents of rat liver. The in vitro study, which used the techniques of ultraviolet spectroscopy and thin-layer chromatography, indicated the formation of a complex of AITC with T4 and Tyr but not with Leu. The presence of a phenyl ring with an OH group at the position para to the alanine side chain is suggested as a prerequisite for the chemical binding of AITC with amino acids. The in vivo experiment involved administration of AITC, T4, or the ALTC–T4 complex by the intraperitoneal route to young male Sprague–Dawley rats for 30 days. AITC exhibited a strong coagulant effect, which was seemingly mediated by the relatively high plasma phospholipid concentration. T4 and the AITC–T4 complex were without a significant effect on blood coagulation. AITC was without effect on liver protein but increased cholesterol, phospholipid, and total lipid contents markedly. The effect of T4 on the liver protein and lipids was not significant. The AITC-T4 complex caused a significant increase in the liver protein and an intermediate rise in the lipids compared with AITC. The increase in plasma and liver lipid concentrations caused by AITC was probably related to increased hepatic lipid production and decreased clearance of the circulating lipids.

Nuclear magnetic resonance studies in liposomes: effects of steroids on lecithin fatty acyl chain mobility

The effects of fourteen sterols on the NMR spectra of liposomes derived from egg yolk phosphatidylcholines were studied by continuous-wave and Fourier-transform measurements at 60 MHz. Sterols were compared for their ability to broaden the acyl methylene resonances of phosphatidylcholine, when incorporated into liposomes at 25% molar ratio. The ratio of the phosphatidylcholine peake heights (acyl methylene: choline N-methyl) was used as a criterion of the relative condensing activity for the different sterols. This ratio was inversely proportional to the molar volume of the incorporated sterol, as measured by the parachor of the compound. Small sterols had little condensing effect, and the larger sterols such as cholesterol and ergosterol had maximum condensing effects. The study confirmed the importance of the sterol side-chain at C-17 as a requirement for sterol-phospholipid interaction.