A comparison of rheumatoid arthritis in Australia and China

A comparison was made of two series of consecutive outpatients with a presumptive diagnosis of rheumatoid arthritis (RA) attending referral centres in Melbourne and Shanghai. No significant differences were observed in disease onset, course, presence of antinuclear antibodies (ANA), or seropositivity. In the Australian series there was a higher frequency of nodules, Raynaud's phenomenon, carpal tunnel syndrome, and 'classical' in comparison with 'definite' disease, and a lower frequency of lymphadenopathy and hepatomegaly. Joint tenderness and soft tissue swelling tended to be more marked in the Chinese series, while deformity and limited range of movement were less severe. Drug therapy was similar overall but influenced by drug availability. Peptic ulceration was recorded in 28% of the Australian series but in only 6% of the Chinese; although 25% of the Chinese were receiving antacids and 6% antiulcerants. X-rays of hands and feet showed more severe disease in the Australian series. The older age group and longer duration of the disease in the Australian patients, who had more chronic and less active disease, may have influenced some of these results.

Human prostate carcinoma causes hypercalcemia in athymic nude mice and produces a factor with parathyroid hormone-like bioactivity

The mechanism of the calcium and phosphorus abnormalities associated with metastatic prostate carcinoma (CaP) is not yet understood. A tumor model was recently established in which 9479, a human CaP from a patient with prostate carcinoma-induced osteomalacia, was heterotransplanted into athymic nude mice (ANM). In the present study the effect of 9479 on ANM was evaluated. Serum calcium (Ca), phosphorus (P), parathyroid hormone (PTH), 1,25-dihydroxyvitamin D3(1,25-(OH)2D3) and urinary cAMP were measured. Ca was markedly elevated in ANM bearing 9479 vs. age-matched controls (C); the increased Ca returned to control level after tumor removal. Serum PTH was lower in 9479-bearing ANM vs. C while urinary cAMP and serum 1,25-(OH)2D3 levels were elevated. In the ANM bearing 9479, there was a decrease in serum P vs. C which returned to normal after tumor removal. Fractional P excretion was greater in 9479 animals than C. Extracts of 9479 were examined for the presence of parathyroid hormone-like bioactivity by measuring stimulation of intracellular cAMP in ROS 17/2.8 cells. Cyclic AMP stimulation which was found was shown to be inhibited by the competitive PTH antagonist [8Nle, 18Nle, 34Tyr]bPTH-(3-34) amide. These data suggest tumor induction of parathyroid hormone-like humoral modulation of calcium, phosphate and vitamin D metabolism in vivo associated with a parathyroid hormone-like prostate carcinoma product.

Defective reticuloendothelial system C3b mediated clearance in rheumatoid arthritis and vasculitis

C3b receptor mediated clearance by the reticuloendothelial system (RES) was tested in vivo using autologous C3b coated, technetium labelled erythrocytes in patients with rheumatoid arthritis (RA) and rheumatoid vasculitis. Diminished C3b mediated erythrocyte clearance was found in all patients with rheumatoid vasculitis and some patients with active RA. Normal C3b mediated clearance was found in some patients with previous vasculitis, in remission when tested. These results are consistent with the hypothesis that acquired dysfunction of RES C3b receptors is implicated in the pathogenesis of rheumatoid vasculitis.

Effect of sulfhydryl-disulfide state on protein phosphorylation: phosphorylation of bovine serum albumin

Bovine serum albumin (BSA) was phosphorylated by the catalytic subunit of cAMP-dependent protein kinase under general protein phosphorylation conditions. The optimal pH for this phosphorylation was 9.0. The K0.5 (the concentration required for 50% of maximal phosphorylation) for BSA at pH 7.5 was 15 microM. One mole of phosphate was incorporated per mole of BSA, and only one phosphopeptide fragment was obtained after extensive proteolysis with trypsin. BSA phosphorylation required dithiothreitol or GSH, but GSH was only one-fiftieth as effective as dithiothreitol. GSSG counteracted the effect of dithiothreitol and GSH. Phosphorylation increased in a time-dependent and dithiothreitol concentration-dependent manner when BSA was preincubated with dithiothreitol. The increase in the incorporation of 32P correlated with the appearance of up to six free sulfhydryl groups. The effect of dithiothreitol on BSA appeared reversible, since reoxidation of reduced BSA decreased its susceptibility to phosphorylation. These experiments showed that this in vitro phosphorylation is dependent on the sulfhydryl-disulfide state of BSA. The possible implications of the sulfhydryl-disulfide state of proteins in the regulation of phosphorylation are discussed.

In vitro studies of parathyroid hormone release: effect of cimetidine

We studied parathyroid hormone (PTH) release from cell suspensions of fresh and cryopreserved human parathyroid tissue. A sensitive PTH assay with midregion specificity and adaptation of "micro" methods of cell plating permitted conservation of tissue (200 microliters aliquots) and high reproducibility (5 to 10 aliquots per experimental condition). Viability of cells in suspension was confirmed by increased PTH release with increased incubation, increased incorporation of tritiated leucine with increased incubation, and incorporation of tritiated leucine following experimental incubation. Because of conflicting reports regarding the in vivo effect of cimetidine on PTH release, we incubated cells from both adenomatous and hyperplastic glands at 0, 10(-4)M, 10(-5)M, and 10(-6)M cimetidine (10(-5)M is therapeutic) and at 0.25, 1 to 1.2, and 2 mM Ca++. Despite occasional statistically significant (P = 0.05) differences in PTH release with and without cimetidine, therapeutic levels of cimetidine had no consistent effect on PTH release from pathologic parathyroid tissue in vitro.

A short-term in vitro drug-screening assay for cancer chemotherapy

In this short-term in vitro assay for detection of tumor cell sensitivity to drugs, we have replaced the traditional soft-agar colony-forming assay with the measurement of DNA synthesis, to determine the cell renewal capability of the tumor cell population. The tumor cells are treated with drugs and cultured for five days. During the last 12--18 h of culture the cells are pulsed with [3H]thymidine, then harvested for scintillation counting. The effects of drugs are expressed as the percentage of DNA synthesis as compared with that of the control. When the % DNA synthesis is less than 40%, the drug is considered to be effective. So far we have studied tumor cells from multiple myeloma, non-Hodgkin's lymphoma, and carcinoma of lung, breast, ovary, stomach, and bladder. The overall negative predictive value is 1.0. The results are available within five days, compared with 21--28 days for completion of soft-agar assays; fewer cells are required; and the process is semiautomated.

Estimation of lactose hydrolysis by freezing point measurements in milk and whey substrates treated with lactases from various microorganisms

beta-Galactosidase concentrates obtained from several microorganisms were used to hydrolyze skim milk, low fat (2%) milk, sweet whey, acid whey, acid whey permeate, and acid whey concentrate. Among acid substrates, the freezing point depression for each 1% lactose hydrolyzed was the greatest with the lactase from Aspergillus niger (0.0501 degrees H); among neutral substrates, the depression was greater in sweet whey (0.0495 degree H) and lesser in low fat milk (0.0445 degrees H). All data were statistically significant. The average freezing point depression for each 1% lactose hydrolyzed wa s0.0468 degrees H (range 0.0436-0.0501 degrees H). Oligosaccharides formed in the lactose hydrolysis inconsistent freezing point readings of the cryoscope at the low freezing points measured, and protease contamination in some lactases may affect the precision of freezing point determination. Hydration and volume of non-protein components in commercial enzymes, unstable color complex formed by lactose and methylamine solution, and difficulty in the use of methylamine solution might cause variations in determination of lactose by the analytical procedure. These factors can be eliminated or minimized. This method is the simplest and quickest estimation of lactose hydrolysis, and it offers great accuracy and consistency.

Temperature-independent thin-film optical waveguide

The concept of having the effective refractive index of an optical waveguide mode be independent of temperature is introduced. It is shown that this concept should be realizable with a Corning 7059 glass thin-film waveguide supported on a SiO(2)-Si substrate for a waveguide thickness of 0.37 microm. Measurements of effective refractive index as a function of temperature confirm this prediction of temperature independence in that they show a very small variation with temperature for a 0.35-microm thick waveguide in comparison with that for a 0.98-microm thick waveguide.

Salicylate absorption from a bismuth subsalicylate preparation

The active ingredient in Pepto-Bismol (PB) (Norwich-Eaton), a common antidiarrheal, is bismuth subsalicylate. The absorption of salicylate after oral PB was studied in six fasted men. Plasma concentrations of total salicylate and the urinary excretion profile of salicylate were determined as a function of time and dose. After 60 ml PB, 500.1 +/- 33.6 mg (mean +/- SD) salicylate were recovered in urine, representing 95.0 +/- 6.4% of salicylic acid equivalents in 60 ml of the formulation. Peak plasma salicylate levels were reached 0.5 to 3 hr after ingestion and averaged 40.1 +/- 17.3 micrograms/ml. Absorption of salicylate was also essentially complete after 15- and 30-ml doses of the antidiarrheal preparation, and a linear relationship between dose and recovery of salicylate in the urine was found. Salicylate kinetics was nonlinear after a multiple-dose regimen of 60 ml every 6 hr for five doses.

A rapidly metabolizing pool of phosphatidylglycerol as a precursor of phosphatidylethanolamine and diglyceride in Bacillus megaterium

Pulse-chase experiments in Bacillus megaterium ATCC 14581 with [U-14C]palmitate, L-[U-14C]serine, and [U-14C]glycerol showed that a large pool of phosphatidylglycerol (PG) which exhibited rapid turnover in the phosphate moiety (PGt) underwent very rapid interconversion with the large diglyceride (DG) pool. Kinetics of DG labeling indicated that the fatty acyl and diacylated glycerol moieties of PGt were also utilized as precursors for net DG formation. The [U-14C]glycerol pulse-chase results also confirmed the presence of a second, metabolically stable pool of PG (PGs), which was deduced from [32P]phosphate studies. The other major phospholipid, phosphatidylethanolamine (PE), exhibited pronounced lags relative to PG and DG in 14C-fatty acid, [14C]glycerol, and [32P]phosphate incorporation, but not for incorporation of L-[U-14C]serine into the ethanolamine group of PE or into the serine moiety of the small phosphatidylserine (PS) pool. Furthermore, initial rates of L-[U-14C]serine incorporation into the serine and ethanolamine moieties of PS and PE were unaffected by cerulenin. The results provided compelling in vivo evidence that de novo PGt, PS, and PE synthesis in this organism proceed for the most part sequentially in the order PGt yields PS yields PE rather than via branching pathways from a common intermediate and that the phosphatidyl moiety in PS and PE is derived largely from the corresponding moiety in PGt, whereas the DG pool indirectly provides an additional source for this conversion by way of the facile PGt in equilibrium or formed from DG interconversion.

Improved circuit for potential fluctuation compensation in the plasma during the electron energy distribution function measurement by a probe

An improved circuit consisting of a simple voltage follower for the measurement of electron energy distribution function in a plasma has been proposed. This circuit makes it possible to eliminate the fluctuation of plasma space potential, the deviation of dc probe voltage caused by the probe current drawing across the plasma resistance, and the attenuation of the second derivative signal during the measurement, simultaneously. Both the probe circuit considerations and the experimental results are presented.

Mechanism of steroid binding to serum proteins

Association and dissociation rate constants of steroid complexes with progesterone-binding globulin (PBG) and with corticosteroid-binding globulin have been determined, utilizing the fluorescence quenching phenomenon observed on steroid binding to protein. Stopped-flow techniques were used in most cases. The dissociation rates of the complexes with steroid-binding proteins of serum are much greater than those of steroid-receptor complexes, in accordance with the biological functions of these two types of proteins. Association of steroids with PBG is accompanied by conformational changes in both components of the complexes. Chemical modification of tryptophan, lysine, and tyrosine in PBG results in inactivation of the binding site; complex formation with progesterone protects against this inactivation. A comparison of the affinity constants of PBG complexes with steroids of different structures leads to a conceptual image of the binding site and to localization of the various forces of interaction over the binding site area.

Carbon dioxide inhibition of yeast growth in biomass production

Saccharomyces cerevisiae was grown under aerobic and substrate-limiting conditions for efficient biomass production. Under these conditions, where the sugar substrate was fed incrementally, the growth pattern of the yeast cells was found to be uniform, as indicated by a constant respiratory quotient during the entire growing period. The effect of carbon dioxide was investigated by replacing portions of the nitrogen in the air stream with carbon dioxide, while maintaining the oxygen content at the normal 20% level, so that identical oxygen transfer rate and atmospheric pressure were maintained for all experiments with different partial pressures of carbon dioxide. Inhibition of yeast growth was negligible below 20% CO2 in the aeration mixture. Slight inhibition was noted at the 40% CO2 level and significant inhibition was noted above the 50% CO2 level, corresponding to 1.6 X 10(-2)M of dissolved CO2 in the fermentor broth. High carbon dioxide content in the gas phase also inhibited the fermentation activity of baker's yeast.