A new rapid and simple non-radioactive assay to monitor and determine the proliferation of lymphocytes: an alternative to [3H]thymidine incorporation assay

A one-step non-radioactive assay to determine the proliferation of murine lymphocytes, lymphoid tumor cells and hybridoma cells is described. This assay requires the addition of Alamar Blue dye to cell cultures and the degree of change in its color, which is reflective of the extent of cellular proliferation, can be determined by an ELISA plate reader. Alamar Blue must be added during the initial phase of cell culture. The pattern of concanavalin A (ConA) or anti-CD3 antibody-induced proliferative response of murine lymphocytes as assessed by Alamar Blue was similar to that of a [3H]thymidine assay. Similarly, the spontaneous proliferation curve of anti-CD3 antibody secreting cell line (YCD3-1), monocytic macrophage cell lines (PU5-1.8, P388D1, J774.1) and myeloma cells (Sp2/0) as determined by Alamar Blue closely resembled that of the [3H]thymidine assay. The minimum detectable number of proliferating cells was comparable in Alamar Blue and [3H]thymidine assays. Since cell lysis/extraction and washing procedures are not involved in the Alamar Blue assay, this approach has several distinct advantages over currently available assays (eg. [3H]thymidine). First, it allows daily monitoring of proliferation without compromising the sterility of cultures. An indication of proliferation can be evaluated (spectrophotometrically or visually) as early as 24 h after ConA stimulation. Second, unlike previously reported assays, Alamar Blue permits further analysis of proliferating cells by other methods. Analysis of cells in culture with Alamar Blue for various surface antigens (CD44, CD45RB, CD4, heat stable antigen) by flow cytometry revealed that the fluorescent profile and relative percentage of cells in cultures with the Alamar Blue were comparable to those without this reagent. The salient advantages of Alamar Blue assay over the [3H]thymidine assay include: (i) non-radioactivity; (ii) simplicity; (iii) less costly; (iv) non-labor intensive; (v) rapidity of assessment of proliferation of large number of samples; (vi) non-toxicity; (vii) usefulness in determining the kinetics of cell growth of hybridomas; and (viii) non-interference of secretion of antibodies by a hybridoma cell line.

The immune system as a potential target for environmental estrogens (endocrine disrupters): a new emerging field

It is now well known that natural (17beta-estradiol) and synthetic (e.g. diethylstilbestrol) estrogens not only affect the reproductive system, but also markedly influence the immune system. Recently, a new class of estrogens that is abundant in the environment (in industrial chemicals, pesticides, and surfactants) has been recognized. Some of these estrogenic chemicals (which are a large subgroup of endocrine disrupters) have also been shown to influence the immune system. This review assimilates growing evidence in wildlife, laboratory animals and to a limited extent in humans, which suggests that environmental chemicals may also affect the immune system. Further studies are needed to ascertain the immunological consequences of exposure to environmental estrogens, especially in humans. At the present time, it is not known whether the human immune system responds to a low dose of environmental estrogens or if environmental estrogens influence certain subsets of human populations, rather than the general population. Conceivably, an alteration of the immune system by environmental estrogens could affect the individuals' ability to mount well-regulated immune responses to microbial and vaccine antigens, allergens, self and tumor antigens. Possible changes in the immune system must be investigated routinely in toxicity studies. A comprehensive mechanistic understanding of potential immunomodulatory chemicals is needed. In this regard, relevant laboratory animals may be especially useful in identifying susceptible periods of life, whether both genders are equally affected, in analysis of changes in target lymphoid organs, and to determine the immunological effects of mixtures of chemicals.

Prevention of autoantibody formation and prolonged survival in New Zealand black/New Zealand white F1 mice fed dehydroisoandrosterone

Dehydroisoandrosterone, administered orally to New Zealand Black/New Zealand White F1 hybrid mice, prevented the formation of antibodies to double-stranded DNA and prolonged survival in this murine model of lupus erythematosus.

Crystal structures of a mutant (betaK87T) tryptophan synthase alpha2beta2 complex with ligands bound to the active sites of the alpha- and beta-subunits reveal ligand-induced conformational changes

Three-dimensional structures are reported for a mutant (betaK87T) tryptophan synthase alpha2beta2 complex with either the substrate L-serine (betaK87T-Ser) or product L-tryptophan (betaK87T-Trp) at the active site of the beta-subunit, in which both amino acids form external aldimines with the coenzyme, pyridoxal phosphate. We also present structures with L-serine bound to the beta site and either alpha-glycerol 3-phosphate (betaK87T-Ser-GP) or indole-3-propanol phosphate (betaK87T-Ser-IPP) bound to the active site of the alpha-subunit. The results further identify the substrate and product binding sites in each subunit and provide insight into conformational changes that occur upon formation of these complexes. The two structures having ligands at the active sites of both alpha- and beta-subunits reveal an important new feature, the ordering of alpha-subunit loop 6 (residues 179-187). Closure of loop 6 isolates the active site of the alpha-subunit from solvent and results in interaction between alphaThr183 and the catalytic residue alphaAsp60. Other conformational differences between the wild type and these two mutant structures include a rigid-body rotation of the alpha-subunit of approximately 5 degrees relative to the beta-subunit and large movements of part of the beta-subunit (residues 93-189) toward the rest of the beta-subunit. Much smaller differences are observed in the betaK87T-Ser structure. Remarkably, binding of tryptophan to the beta active site results in conformational changes very similar to those observed in the betaK87T-Ser-GP and betaK87T-Ser-IPP structures, with exception of the disordered alpha-subunit loop 6. These large-scale changes, the closure of loop 6, and the movements of a small number of side chains in the alpha-beta interaction site provide a structural base for interpreting the allosteric properties of tryptophan synthase.

Quantification of infarction in cross sections of canine myocardium in vivo with positron emission transaxial tomography and 11C-palmitate

To assess myocardial infarction quantitatively in 15 mm thick transverse sections of the canine heart in vivo we utilized a new technique, positron emission transaxial tomography (PETT) and cyclotron-produced 11C-palmitate (11C-P) injected intravenously. Results were compared to regional myocardial creatine phosphokinase (CPK) depletion, diminished 14C-palmitate accumulation in tissue extracts, and infarction estimated morphometrically 48 hours after coronary occlusion. CPK activity and 14C-P content declined in parallel in transmural biopsies (N=44) from normal and ischemic zones (r=.92) in six dogs; and infarct in 10 mm thick cross sections of the entire left ventricle estimated morphometrically (N=26) in six other animals correlated with CPK depletion in contiguous 2.5 mm thick slices (r=.92). When the percentage of infarction in 15 mm thick cross sections was assessed tomographically in six other dogs 48 hours after coronary occlusion with 11C-P injected intravenously, results correlated with infarction in corresponding cross sections from the same hearts estimated morphometrically (r=.97, N=9) and by analysis of CPK depletion (r=.93, N=9). Thus, PETT permits estimation of infarction in cross sections of the left ventricle in vivo after intravenous injection of 11C-palmitate.

Sex hormones and the immune system--Part 2. Animal data

Sex hormones have physiological and pathological (autoimmune conditions) effects on the immune system. Studies in experimental animal models of human autoimmune diseases have clearly shown that sex hormones regulate the expression, severity and course of autoimmune diseases. Sex hormones affect the function of T, B and NK cells, and macrophages. Precisely how sex hormones affect lymphocytes is a highly complex question. Sex hormones can modulate the immune system, perhaps directly (e.g. thymic reticular tissue), or indirectly via host and many oestrogen target tissues, including the central nervous system hypothalamic-pituitary axis (the neuroendocrine tissues). The effects of sex hormones on the immune system (immunosuppression or immunopotentiation) may vary, even with the same hormone. For example, oestrogen can increase IgA levels in the uterus, but decrease IgA levels in the vagina or have no effect in lacrimal tissues (Sullivan, 1989). Therefore the effects of sex hormones on the immune system cannot be generalized but must be evaluated independently. Some of the reasons for variability in results have been reviewed in detail elsewhere (Steinberg et al, 1979; Ansar Ahmed et al, 1985b). These include, dose of hormones, age and sex-hormonal status of animals, route and time of administration, the immunocompetence of the host, stress, the metabolism of hormones (e.g. metabolism of testosterone to oestrogen) resulting in alteration of biological activity, and differential response to various antigens. The initial encounter of sex hormones with the type of target cells, the variability of secondary messengers and gene activation events are other important considerations. The effects of sex hormones on the immune system to modulate immune responses are unequivocal. The burgeoning advances in cellular immunology, endocrinology and molecular biology, should provide a better understanding of: (1) the interactions of hormones with the immune system; (2) how hormones activate specific genes; and (3) how hormones influence intracellular communication. In a clinical situation, it is hoped that androgenic compounds which lack virilizing effects, but possessing the desired immunomodulatory effects, will eventually be synthesized. These hormone analogues, in combination with specific (non-toxic) oestrogen antagonists, may offer new therapeutic avenues.

Gender and risk of autoimmune diseases: possible role of estrogenic compounds

A striking common feature of many autoimmune diseases in humans and experimental animals, despite differences in pathology, is that females are highly susceptible to autoimmune conditions compared to males. In several animal models, estrogens promote, whereas androgens abrogate, B-cell-mediated autoimmune diseases. To understand mechanisms by which estrogens regulate autoimmunity, it is first necessary to decipher estrogen effects on the normal immune system. Estrogen treatment of nonautoimmune mice diminished lymphocyte numbers in both developmental and mature lymphoid organs. Estrogen dysregulated T- and B-cell balance by inducing selective T-cell hypoactivity and B-cell hyperactivity. Even though estrogen did not alter the relative percentages of splenic T-cell subsets, splenic lymphocytes had a reduced proliferative response to T-cell stimulants and were refractory to rescue from activation-induced apoptosis compared to cells from placebo-treated mice. In contrast, estrogen induced B-cell hyperactivity (promoted autoantibodies to double-stranded DNA and phospholipids, increased numbers of plasma cells, and increased autoantibody yield per B cell). Note that treatment of normal mice with estrogen can alter T- and B-cell regulation and overcome B-cell tolerance to result in autoimmunity in normal individuals. Could environmental estrogens promote some human autoimmune disorders? Is there a link between environmental estrogens and autoimmune disorders, especially since these disorders are reported possibly more frequently? These provocative questions warrant investigation. Our findings on immunomodulatory effects may serve as a benchmark to examine whether endocrine-disrupting chemicals will have similar immunologic effects.

Velocity measurements in steady flow through axisymmetric stenoses at moderate Reynolds numbers

The velocity field in the neighborhood of axisymmetric constrictions in rigid tubes was investigated using laser Doppler anemometry and flow visualization. Upstream flow conditions were steady; and Reynolds numbers were in the range 500-2000, values which are representative of the larger arteries in humans. Stenoses of 25, 50 and 75% area reduction were studied. Velocity profiles are presented in sufficient detail to allow comparison with computational biofluid dynamics models. Wall shear stresses were estimated from the near wall velocity gradient, and the nature of observed poststenotic flow disturbances is discussed. Results indicate that flow disturbances of discrete oscillation frequency may be more valuable than turbulence as an indicator of early stages of stenosis development. Additionally, despite the fact that poststenotic turbulence exists for the higher degrees of stenosis and Reynolds numbers, the resulting wall shear stresses are only three to four times greater than the Poiseuille value and are considerably less than the wall shear stress within the stenosis itself.

Exchange of K+ or Cs+ for Na+ induces local and long-range changes in the three-dimensional structure of the tryptophan synthase alpha2beta2 complex

Monovalent cations activate the pyridoxal phosphate-dependent reactions of tryptophan synthase and affect intersubunit communication in the alpha2beta2 complex. We report refined crystal structures of the tryptophan synthase alpha2beta2 complex from Salmonella typhimurium in the presence of K+ at 2.0 angstrom and of Cs+ at 2.3 angstrom. Comparison of these structures with the recently refined structure in the presence of Na+ shows that each monovalent cation binds at approximately the same position about 8 angstrom from the phosphate of pyridoxal phosphate. Na+ and K+ are coordinated to the carbonyl oxygens of beta Phe-306, beta Ser-308, and beta Gly-232 and to two or one water molecule, respectively. Cs+ is coordinated to the carbonyl oxygens of beta Phe-306, beta Ser-308, beta Gly-232, beta Val-231, beta Gly-268 and beta Leu-304. A second binding site for Cs+ is located in the beta/beta interface on the 2-fold axis with four carbonyl oxygens in the coordination sphere. In addition to local changes in structure close to the cation binding site, a number of long-range changes are observed. The K+ and Cs+ structures differ from the Na+ structure with respect to the positions of beta Asp-305, beta Lys-167, and alpha Asp-56. One unexpected result of this investigation is the movement of the side chains of beta Phe-280 and beta Tyr-279 from a position partially blocking the tunnel in the Na+ structure to a position lining the surface of the tunnel in the K+ and Cs+ structures. The results provide a structural basis for understanding the effects of cations on activity and intersubunit communication.

Combination hyperthermia and radiation therapy for malignant melanoma

Since 1975, clinical studies have been carried out to determine whether radiation when combined with localized hyperthermia evokes improved tumor control compared to that achieved with radiation alone. Local tumor hyperthermia was achieved using radiofrequency inductive heating at 27.12 MHz. In bulky lesions (greater than 100 cm3), radiofrequency conductive heating at 13.56 MHz was also used. More than 100 lesions in 38 patients were treated with radiation alone and hyperthermia in combination with radiation. Most lesions were treated either twice a week or once a week, depending on radiation dose fractionation scheme used. The overall result of tumor control rate of the combined therapy is superior to radiation therapy alone (75% versus 46%; P less than 0.01). No enhanced normal tissue morbidity was seen following the combined therapy. The detailed analysis of the treatment results shows that the tumor control rate is dependent on dose per fraction, the total dose, and the initial tumor volume. The radiation alone, at high doses per fraction, was effective in controlling 80% of the lesions, if the tumor volume was less than 10 cm3, compared to 30% when the tumor volumes were larger. The combination therapy, on the other hand, effected 80% local tumor control regardless of the tumor volume. The importance of good thermal distribution within the tumor volume, selective heating of the tumor tissues and the sequence and time interval between the combined therapy is discussed.

Pulsatile poststenotic flow studies with laser Doppler anemometry

The pulsatile flow field distal to axisymmetric constrictions in a straight tube was studied using laser Doppler anemometry. The upstream centerline velocity waveform was sinusoidal at a frequency parameter of 7.5 and mean Reynolds number of 600. Stenosis models of 25, 50 and 75% area reduction were employed and velocity data were derived by ensemble averaging methods. Extensive measurements of the pulsatile velocity profiles are reported, and wall shear rates were computed from the near wall velocity profile gradients. The experiments indicate that a permanent region of poststenotic flow separation does not exist even for the severest constriction, in contrast to results for steady flow. Values of wall shear stress were greatest near the throat of the constriction and were relatively low in the poststenotic region, including the region of most intense flow disturbance. Turbulence was found only for the 75% stenosis model and was created only during a segment of the cycle. Although much emphasis has been placed upon turbulence in the detection of arterial stenoses, particularly as identified by Doppler ultrasound spectral broadening, the present study implies that identification of flow disturbances of an organized nature may be more fundamental in recognizing mild to moderate disease. Additionally, the relationship of these flow field results to the animal aortic coarctation model often employed in atherogenesis studies is discussed.

Flow disturbance measurements through a constricted tube at moderate Reynolds numbers

Instantaneous velocities in the field distal to contoured axisymmetric stenoses were measured with a laser Doppler anemometer. Upstream flow conditions were steady and spanned a range of Reynolds numbers from 500 to 2000. Autocorrelation functions and spectra of the velocity were employed to describe the nature of fluid dynamic disturbances. Depending upon the degree of stenosis and the Reynolds number, the flow field contained disturbances of a discrete oscillation frequency, of a turbulent nature, or both. If turbulence was detected in a given experiment, it was always preceded upstream by velocity oscillations at discrete frequency arising from vortex shedding. For mild degrees of stenosis (50% area reduction or less) the intensity of flow disturbances was relatively low until the Reynolds number exceeded 1000, thus highlighting difficulties to be expected in employing flow disturbance detection as a diagnostic tool in the recognition of early atherosclerosis in major arteries. In view of the relatively high noise levels inherent in noninvasive Doppler ultrasound systems employed clinically, it seems unlikely that detection of stenosis of less than 50% area reduction is feasible unless the Reynolds numbers exceed 1000 or unless pulsatility introduces new unsteady flow features beyond those studied here.

Natural and synthetic flavonoid derivatives as new potential tyrosinase inhibitors: a systematic review

Tyrosinase is a multifunctional glycosylated and copper-containing oxidase that is highly prevalent in plants and animals and plays a pivotal role in catalyzing the two key steps of melanogenesis: tyrosine's hydroxylation to dihydroxyphenylalanine (DOPA), and oxidation of the latter species to dopaquinone. Melanin guards against the destructive effects of ultraviolet radiation which is known to produce considerable pathological disorders such as skin cancer, among others. Moreover, the overproduction of melanin can create aesthetic problems along with serious disorders linked to hyperpigmented spots or patches on skin. Several skin-whitening products which reduce melanogenesis activity and alleviate hyperpigmentation are commercially available. A few of them, particularly those obtained from natural sources and that incorporate a phenolic scaffold, have been exploited in the cosmetic industry. In this context, synthetic tyrosinase inhibitors (TIs) with elevated efficacy and fewer side effects are direly needed in the pharmaceutical and cosmetic industries owing to their protective effect against pigmentation and dermatological disorders. Furthermore, the biological significance of the chromone skeleton and its associated medicinal and bioactive properties has drawn immense interest and inspired many researchers to design and develop novel anti-tyrosinase agents based on the flavonoid core (2-arylchromone). This review article is oriented to provide an insight and a deeper understanding of the tyrosinase inhibitory activity of an array of natural and bioinspired phenolic compounds with special emphasis on flavonoids to demonstrate how the position of ring substituents and their interaction with tyrosinase could be correlated with their effectiveness or lack thereof against inhibiting the enzyme.

A dye-based lymphocyte proliferation assay that permits multiple immunological analyses: mRNA, cytogenetic, apoptosis, and immunophenotyping studies

Alamar Blue in the microenvironment of activated cells, undergoes color change and also becomes fluorescent. By using the Alamar Blue dye, we have reported a non-radioactive colorimetric assay to indirectly determine proliferation of murine lymphocytes. We further show that the pattern of mitogen-induced proliferation assessed fluorometrically was comparable to the 3H-thymidine incorporation assay (3H-Tdr assay). Of practical importance is that the color/fluorescence changes were stable at 4 degrees C in the dark for 3-4 weeks. In immunological studies, it is important to further analyze lymphocytes that have undergone activation and/or proliferation. This is not possible with the standard 3H-Tdr assay, which requires lysis of cells. In contrast, the Alamar Blue-based non-radioactive assay does not require cell lysis. We therefore tested the hypothesis that further analysis of lymphocytes is possible, after assessing the proliferation using Alamar Blue. Following assessment of proliferation in a 72-h culture, the Alamar Blue dye was washed-off and cells were re-utilized to perform additional immunological analysis. Short-term exposure of lymphocytes to Alamar Blue was not detrimental to lymphocytes, as assessed by trypan blue exclusion and the propidium iodide (PI) assays. Exposure of dexamethasone-treated cells to Alamar Blue did not interfere with the performance of apoptosis assays, such as flow cytometric analysis of PI-stained cells and microscopic examination of ethidium bromide/acridine orange-stained cells. In addition, prior exposure of lymphocytes to Alamar Blue did not affect the analysis of chromosomal aberrations or the visualization of cell surface antigens by flow cytometry. Further, the expression of cytokine mRNA in lymphocytes previously exposed to Alamar Blue was similar to unexposed cells. Together, a notable advantage of this assay is that it now enables the investigator to maximize information by following or correlating proliferation with other immunologic events in the same cells.

The association of increased plasma MB CPK activity and irreversible ischemic myocardial injury in the dog

To evaluate the concordance between elevated plasma MB CPK and irreversible myocardial ischemic injury, coronary occlusion was induced for 10 minutes to 48 hours in 21 open chest dogs and 13 conscious animals. Results of plasma CPK and MB CPK assayed in samples obtained serially ofr 24 hours were compared to microscopic changes in hearts from the same animals examined 48 hours after occlusion. Twelve of the 34 dogs died within two hours after coronary occlusion. Among the surviving 22 dogs, one failed to exhibit gross of electrocardiographic evidence of ischemia and was therefore excluded. Twelve had coronary occlusion maintained for 30 minutes or longer and in 11 of these peak plasma MB CPK activity exceeded thenormal range (mean +/- 2 SD) and baseline values by at least 100%. Necrosis was present in the hearts from each manifested by nuclear pyknosis, eosinophilia, shrinkage of cytoplasm, and leukocytic infiltration. In the remaining nine dogs with occlusion for less than 30 minutes, peak plasma MB CPK activity was not elevated and necrosis was not detected. The close concordance between plasma MB CPK elevations and myocardial necrosis was significant (chi2 = 14.5, P less than 0.001), and thus, increased plasma MB CPK activity reflected irreversible myocardial ischemic injury.

Estrogen increases the number of plasma cells and enhances their autoantibody production in nonautoimmune C57BL/6 mice

The immunological consequences of chronic estrogen exposure in normal individuals are not known, particularly in relation to B cells. In this study, by employing ELIspot, image cytometry, flow cytometry, cytology, and ELISA, we show that long-term exposure of normal mice to estrogen activates B cells to produce higher numbers of not only immunoglobulin-producing cells, but also autoantibody-producing cells. Estrogen promoted a decrease in B220(+) splenic lymphocytes, but resulted in a 10-fold increase in plasma cells. Further, the output of immunoglobulins including autoantibodies from individual plasma cells from estrogen-exposed mice was markedly increased, suggesting B cell hyperactivity. Importantly, our findings show that treatment of normal mice, solely with estrogen, can override B cell tolerance and promote autoreactive B cells in normal individuals.

Synthesis, characterization and structure effects on selectivity properties of silica gel covalently bonded diethylenetriamine mono- and bis-salicyaldehyde and naphthaldehyde Schiff(,)s bases towards some heavy metal ions

Four silica gel-immobilized new metal chelate Schiff(,)s bases were synthesized (I-IV). Silica gel chemically bonded diethylenetriamine mono-naphthaldehyde and mono-salicyaldehyde Schiff's bases (phases I and III) were produced via the interaction of silica gel-modified diethylenetriamine with naphthaldehyde and salicylaldehyde, respectively. However, phases II and IV arose through the interaction of bis-naphthaldehyde and bis-salicylaldehyde Schiff(,)s bases of diethylenetriamine with 3-chloropropyltrimethoxysilane modified silica gel. The characterization of such new phases, their capabilities towards selective extraction or separation of Fe(III), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) ions were studied and evaluated by both batch and column techniques as a function of pH and time of contact. Phases III and I showed high performance towards Cu(II) extraction, where their Cu(II) sorption determined to be 0.957 and 0.940 mmol g(-1), respectively. However, for phases IV and II, the great affinity was devoted to Fe(III) extraction followed by Cu(II) ions. The reactivity of metal ion sorption was discussed in the light of effects of bulkiness as well as orientation of immobilized chelate on sorbent reactivity. Donor sites of phases III and I (diethylenetriamine and azomethene nitrogens along with phenolic hydroxyl group oxygen) are fully active, whereas phases IV and II are partially active with only participation of oxygen and azomethene nitrogen. The order of increasing thermal stability (IV<II<I<III) and fastness of metal uptake equilibration process coincides satisfactorily with decreasing bulkiness of the chelate. Results of separation under dynamic conditions of binary mixtures containing Cu(II) with Ni(II), Zn(II), Cd(II) and Pb(II) using phase III are in accordance with its selectivity towards Cu(II) retention relative to the other coexisting ions.

Antibodies to cardiolipin in normal C57BL/6J mice: induction by estrogen but not dihydrotestosterone

Autoantibodies against cardiolipin, a phospholipid, have been demonstrated in a variety of pathological states including several autoimmune conditions in humans and in certain lupus-prone mice. In this study we detected antibodies reactive to cardiolipin in normal C57BL/6J mice by ELISA. The autoantibodies are detected less frequently in the serum of male than in female mice, suggesting the influence of sex hormones. The relative refractoriness of normal male mice to the induction of anticardiolipin antibodies is not due to the suppressive effects of male hormones, since prepubertal orchiectomy has little influence on this autoantibody. Further, dihydrotestosterone treatment of orchiectomized mice has minimal effect on anticardiolipin antibodies. However, orchiectomized mice when given estrogen develop a marked increase in the incidence as well as the levels of these autoantibodies. Similarly, estrogen treatment of female mice further augments the incidence and the levels of these autoantibodies. Estrogen-treated mice also have antibodies reactive against other membrane phospholipids including phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylcholine (PC) and phosphatidylethanolamine (PE). The intensity of binding of autoantibodies to the above phospholipids varies among individual mice. To our knowledge, this is the first report on the demonstration of antiphospholipid autoantibodies in normal mice and induction of these antibodies by estrogen.

Vitamin-D-deficiency rickets in Kuwait: the prevalence of a preventable disease

Two hundred and fifty children with clinical, biochemical and radiological evidence of vitamin-D-deficiency rickets were studied over a period of 5 years. Their ages ranged from 1 month to 2 years. Breastfed infants formed 63% of total cases. Intramuscular therapy with vitamin D in a dose of 600,000 IU, deep intramuscular, proved to be safe and effective. In contrast, oral vitamin D did not provide such satisfactory results, presumably owing to poor patient/parental compliance. This report reveals that vitamin-D-deficieny rickets is common in Kuwait in spite of abundant sunlight all through the year because children are wrapped up and kept indoors. Insufficient intake of vitamin D is another important factor in the pathogenesis of vitamin-D-deficiency rickets in Kuwait.

Recent advances in combretastatin based derivatives and prodrugs as antimitotic agents

The dynamic and crucial role of tubulin in different cellular functions rendered it a promising target in anticancer drug development. Combretastatin A-4 (CA-4), an inhibitor of tubulin polymerization isolated from natural sources, is a lead molecule with significant cytotoxicity against tumour cells. Owing to its non polar nature it exhibits low solubility in natural biological fluids, thereby prompting the development of new CA-4 based derivatives. The modification of this lead molecule was mostly carried out by keeping the crucial cis-orientation of the double bond intact, along with a trimethoxyphenyl aromatic ring, by employing different approaches. The issue of solubility was also addressed by the development of water soluble prodrugs of CA-4. The present review highlights the investigations into the parallel development of both new CA-4 based derivatives and prodrugs in the past few years.

Journey of anthraquinones as anticancer agents - a systematic review of recent literature

Anthraquinones are privileged chemical scaffolds that have been used for centuries in various therapeutic applications. The anthraquinone moiety forms the core of various anticancer agents. However, the emergence of drug-resistant cancers warrants the development of new anticancer agents. The research endeavours towards new anthraquinone-based compounds are increasing rapidly in recent years. They are used as a core chemical template to achieve structural modifications, resulting in the development of new anthraquinone-based compounds as promising anticancer agents. Mechanistically, most of the anthraquinone-based compounds inhibit cancer progression by targeting essential cellular proteins. Herein, we review new anthraquinone analogues that have been developed in recent years as anticancer agents. This includes a systematic review of the recent literature (2005-2021) on anthraquinone-based compounds in cell-based models and key target proteins such as kinases, topoisomerases, telomerases, matrix metalloproteinases and G-quadruplexes involved in the viability of cancer cells. In addition to this, the developments in PEG-based delivery of anthraquinones and the toxicity aspects of anthraquinone derivatives are also discussed. The review dispenses a compact background knowledge to understanding anthraquinones for future research on the expansion of anticancer therapeutics.

Estrogen induces the development of autoantibodies and promotes salivary gland lymphoid infiltrates in normal mice

There are important bidirectional interactions between the immune and the endocrine system. Sex hormones influence the immune system throughout life including postnatal and prenatal stages. For example, we find that administration of estrogen to normal mice markedly augments the ability of CD5+ B cells to express their autoimmune potential by producing increased numbers of plaque-forming cells (APFC) to bromelain-treated mouse erythrocytes (Br-ME). The effect of sex hormones on immune function at the most critical stage of development, the prenatal period, remains unstudied. We hypothesize that an imbalance of the in utero sex hormone microenvironment critically influences the fetal immune system. We have termed this influence immunological imprinting. After birth this imprinting could contribute to immune-mediated disorders. To test this hypothesis, we developed a mouse model in which normal mice were prenatally exposed to estrogens. In preliminary experiments, these mice produced higher numbers of APFC to Br-ME, particularly in the peritoneal cavity cell exudates. Furthermore, mice prenatally exposed to estrogens had accelerated development of autoimmune salivary gland lesions indistinguishable from Sjögren's syndrome (SS) in humans. Further experiments are warranted to confirm these findings. The prenatal effects of estrogen may have relevance for familial and neonatal autoimmune syndromes.