Application of Monte Carlo-based statistical significance determinations to the Beta Cephei stars V400 Car, V401 Car, V403 Car and V405 Car

We have used Lomb-Scargle periodogram analysis and Monte Carlo significance tests to detect periodicities above the 3-sigma level in the Beta Cephei stars V400 Car, V401 Car, V403 Car and V405 Car. These methods produce six previously unreported periodicities in the expected frequency range of excited pulsations: one in V400 Car, three in V401 Car, one in V403 Car and one in V405 Car. One of these six frequencies is significant above the 4-sigma level. We provide statistical significances for all of the periodicities found in these four stars.Comment: 11 pages, 17 figure

Mesothelial reaction to asbestos and other irritants after intraperitoneal injection

ArticleThe original publication is available from http://www.samj.org.zaBibliographyTen groups of rats were injected intraperitoneally with one of the following suspensions; standard reference crocidolite; acid treated crocidolite; crocidolite + iron oxide; crocidolite + silica; iron oxide; silica; long fiber crocidolite; short fiber crocidolite; long fiber glass and short fiber glass. Two rats from each group were killed at 45, 90, 150, 240 and 330 days respectively, and the pathology induced by the different suspensions was studied histologically at each time interval. No evidence in support of the chemical induction theory of mechanical irritation theory in the pathogenesis of peritoneal mesotheliomas could be found, although all the suspensions except iron oxide caused a reactive mesothelium.Publishers' versio

The effect of oxygen and paraquat on the 14C-glucose oxidation of rabbit alveolar macrophages and lung slices

CITATION: Rossouw, D. J. & Engelbrecht, F. M. 1979. The effect of oxygen and paraquat on the 14C-glucose oxidation of rabbit alveolar macrophages and lung slices. South African Medical Journal, 55:558-560.The original publication is available at http://www.samj.org.zaIn this study, we measured the effects of different concentrations of paraquat (0.01 mM and 1.0 mM) on the 1-14CO2 and 6-14CO2 production of rabbit lung slices and isolated alveolar macrophages, in 20% and 95% oxygen phases respectively. A 95% oxygen phase induced an increase in the 6-14C-glucose oxidation of control lung slices over a 3-hour period, while the increased activity of the pentose pathway over the first 2 hours started to decline during the third hour of incubation. Paraquat (1.0mM) in 20% oxygen caused a consistent increase in the 6-14CO2 production by lung slices, but in a 95% oxygen phase gradually inhibited the 6-14C-glucose oxidation over a period of 3 hours. The pentose phosphate pathway was highly significantly stimulated by 1.0 mM paraquat in 20% and 95% oxygen over 3 hours. When isolated alveolar macrophages (viability 95%) were incubated in a 20% and a 95% oxygen phase respectively, both the 6-14C-glucose oxidation rates were significantly inhibited by 1.0 mM paraquat after 1 hour. Our results confirmed the initial increase in glycolytic metabolism induced by paraquat, but also indicated that the 6-14CO2 production was significantly inhibited by paraquat when lung slices were incubated in a 95% oxygen phase. The fact that the glucose metabolism in alveolar macrophages is more sensitive to paraquat exposure than that of cells in lung slices may be related to the genesis of the intra-alveolar pulmonary lesions described in the literature.Publisher’s versio

The effect of paraquat on the aerobic metabolism of rabbit alveolar macrophages and lung fibroblasts

CITATION: Rossouw, D. J. & Engelbrecht, F. M. 1979. The effect of paraquat on the aerobic metabolism of rabbit alveolar macrophages and lung fibroblasts. South African Medical Journal, 55:20-23.The original publication is available at http://www.samj.org.zaIn this study the effects of paraquat on the aerobic metabolism and viability of isolated rabbit alveolar macrophages and lung fibroblasts were investigated, and compared with the effects of other known metabolic inhibitors, i.e. sodium fluoride (NaF) and potassium cyanide (KCN). The manometrically and polarographically determined endogenous oxygen consumption of lavaged alveolar macrophages compared very well (180,9 ± 35,8 and 169,3 ± 26,8 nmol per 106 viable cells per hour respectively). Exogenous glucose (10 mM) and autologous serum (1:3 v/v) added to the medium had no significant effect on the basal respiration rate. The mean cell protein content, determined by the micro-Kjeldahl and Lowry techniques, amounted to 242,6 ± 37,6 μg/106 macrophages. Paraquat (2 mM), like NaF (20 mM) and KCN (5 mM), decreased the viability of the macrophages far less than it did the oxygen utilization of the viable cells, and resulted in an 80% inhibitin of oxygen uptake. In contrast, paraquat (1 mM) induced a marked stimulation (230%) of the cyanide-insensitive respiration of alveolar macrophages. The concentrations of paraquat (nmol/103 cells) which reduce macrophage metabolism to almost zero were virtually non-toxic to fibroblasts, as measured by their oxygen consumption.Publisher’s versio

Charge-Spin Separation in 2D Fermi Systems: Singular Interactions as Modified Commutators, and Solution of 2D Hubbard Model in Bosonized Approximation

The general 2-dimensional fermion system with repulsive interactions (typified by the Hubbard Model) is bosonized, taking into account the finite on-shell forward scattering phase shift derived in earlier papers. By taking this phase shift into account in the bosonic commutation relations a consistent picture emerges showing the charge-spin separation and anomalous exponents of the Luttinger liquid.Comment: Latex file 14 pages. email: [email protected]

Occurrence and Transmission of Grapevine Virus A in South African grapevines

Antiserum prepared to a local isolate of grapevine virus A (GVA) was used in immunosorbent electron microscopy (ISEM) with decoration and in an unlabelled antibody enzyme-linked immunosorbent assay (ELISA) for the screening of grapevine sources for the presence of virus. GV A occurred extensively in grapevine plantings showing visual symp· toms of leafroll or indexing positive for leafroll. GV A was found not to be associated with either stem pitting or fleck symptoms. It occurred mostly in association with undecorated closterovirus (CV)-like particles. Limited ISEM with decoration of the CV-like particles using antiserum to a Swiss isolate of CV 2 200 nm, (CV type I) confirmed the presence of a second CV in local grapevine sources. In addition, it indicated the presence of a third CV -like particle longer than GVA. GVA together with undecorated CV-like particles were also detected in initially GVA-free LN-33 grapevines growing under field conditions and naturally infected with Ieafroll. GV A and CV type I were also present in the vine mealybug Planococcus ficus, following exposure to a grapevine source carrying these viruses. H'lwever, due to lack of CV type I antiserum, only GV A was confirmed in grapevine following controlled transmissions with P. ficus although undecorated CV -like particles were present. The reliability of the ELISA detection procedure appears to be influenced by seasonal fluctuations in GV A concentrations

Thyroid nodule management: clinical, ultrasound and cytopathological parameters for predicting malignancy

Although fine-needle aspiration cytology is considered to be the reference method for evaluating thyroid nodules, the results are inaccurate in approximately 10-30% of cases. Several studies have attempted to predict the risk of malignancy in thyroid nodules based on age, nodularity, thyrotropin values, thyroid autoimmune disease, hot/cold nodule status, and ultrasound parameters. However, no consensus has been found, and none of these parameters has significantly affected patient management. The management of indeterminate thyroid nodules and re-biopsies of nodules with initially benign cytological results remain important and controversial topics of discussion. The Bethesda cytological system and several studies on the use of molecular markers to predict malignancy from cytological samples of thyroid nodules need further clarification. More in-depth discussions among and continuous education of the specialists involved in treating thyroid disease are necessary to improve the management of these patients. This review aims to examine the clinical, laboratory, ultrasound, and scintigraphic parameters that can be used for thyroid nodule management

Metabolic changes in the lungs after ischaemia

CITATION: Engelbrecht, F. M., Edwards, I. J. & De Beer, D. P. 1980. Metabolic changes in the lungs after ischaemia. South African Medical Journal, 58:409-413.The original publication is available at http://www.samj.org.zaThe effects of variable periods of ischaemia on the isolated lungs of rats and rabbits, stored for up to 6 hours at 4°C, 21°C and 37°C under standardized conditions, were investigated in vitro in terms of oxygen consumption, the rate of 1-14C-leucine incorporation into soluble proteins, and 1-14C-palmitate incorporation into total phospholipids and lipid fractions. The endogenous oxygen uptake of rat lung slices in an air phase, from tissues stored at 4°C and 21°C under ischaemic conditions for 6 hours and at 37°C for 4 hours, was significantly different from the control values. The oxygen uptake of lungs from animals anaesthetized with pentobarbitone prior to exsanguination and stored for only 2 hours at 37°C differed significantly from control values. Judged by the rate of incorporation of radiolabelled leucine into soluble proteins and that of palmitate into total lipids and phospholipids of lungs after storage for increasing periods at 4°C and 37°C, significant differences were already found after 1 1/2 hours. From this observation it would appear that these parameters are very sensitive indicators for assessing irreversible lung damage due to ischaemia.Publisher’s versio

Quantitative Changes In Antibodies Against Onchocercal Native Antigens Two Months Postivermectin Treatment Of Onchocerciasis Patients

Serum antibodies to Onchocerca volvulus native sodium duodecylsulphate slat extracted antigens and epitopes recognized by three monoclonal antibodies designated Cam8, Cam22, and Cam28 were measured using indirect (sandwich) and competitive enzyme-linked immunosorbent assay (ELISA). Paired serum samples (n=32) were obtained before and two months post-ivermectin treatment. Those with increases of ten percent and above (≥10%) were 16 (50%) for IgG, 13 (40.7%) for both IgG1 and IgG4. Nine (28.2%) for IgM, eight (25%) for IgG3, IgA with four (12.5%) was the least, while IgG2 was not assayed due to cross-reaction. The higher increases in IgG, IgG1 and IgG4 antibodies in females (n=16) than males (n=16) were significant by T-test of unpaired data (

Sensitivity of some Immunoglobulin G class and subclass antibodies to adult Onchocerca volvulus SDS-extracted antigens.

Indirect sandwich enzyme-linked immunosorbent assay (ELISA) was used to measure serum antibody responses in onchocerciasis patients. Apparently, IgG antibody class was more sensitive than IgG1, IgG3 and IgG4 responses to Onchocerca volvulus adult worms sodium duodecyl sulphate (SDS) extracted crude antigens in proven clinical and parasitological cases (n=95). Sensitivity varied slightly among the IgG1, IgG3 and IgG4 isotypes. All cases were positive for IgG, with 98%, 97% and 96% for the IgG isotypes respectively. Those with evidences of palpable nodule and skin microfilariae (n=32) were all seropositive (100%) for the three IgG isotypes-assays. A decrease in seropositivity was recorded among the assumed endemic normals or those with no evidence of infection (n=19), yet IgG recorded the highest with 90% and IgG4 was the least with 58%. It is concluded that the IgG1 and IgG3 assays have great potential as a screening test, while IgG4 could serve as a confirmatory test. These assays could be useful in detecting cases elusive to parasitological and clinical prognosis particularly in post-control surveillance situations. Keywords: Onchocerca volvulus, Serology, sensitivity, Screening, Diagnosis, Antigens and Antibodies