Supraoptimal Doses Research Articles

Nanofertilizers for agricultural and environmental sustainability

Indiscriminate use of chemical fertilizers in the agricultural production systems to keep pace with the food and nutritional demand of the galloping population had an adverse impact on ecosystem services and environmental quality. Hence, an alternative mechanism is to be developed to enhance farm production and environmental sustainability. A nanohybrid construct like nanofertilizers (NFs) is an excellent alternative to overcome the negative impact of traditional chemical fertilizers. The NFs provide smart nutrient delivery to the plants and proves their efficacy in terms of crop productivity and environmental sustainability over bulky chemical fertilizers. Plants can absorb NFs by foliage or roots depending upon the application methods and properties of the particles. NFs enhance the biotic and abiotic stresses tolerance in plants. It reduces the production cost and mitigates the environmental footprint. Multitude benefits of the NFs open new vistas towards sustainable agriculture and climate change mitigation. Although supra-optimal doses of NFs have a detrimental effect on crop growth, soil health, and environmental outcomes. The extensive release of NFs into the environment and food chain may pose a risk to human health, hence, need careful assessment. Thus, a thorough review on the role of different NFs and their impact on crop growth, productivity, soil, and environmental quality is required, which would be helpful for the research of sustainable agriculture.

Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Sitagliptin Phosphate Monohydrate

Sitagliptin is an antihyperglycemic drug used in adults for the treatment of diabetes Type 2. Literature data and in-house experiments were applied in this monograph to assess whether methods based on the Biopharmaceutics Classification System (BCS) could be used to assess the bioequivalence of solid immediate-release (IR) oral dosage forms containing sitagliptin phosphate monohydrate, as an alternative to a pharmacokinetic study in human volunteers. The solubility and permeability characteristics of sitagliptin were reviewed according to the BCS, along with dissolution, therapeutic index, therapeutic applications, pharmacokinetics, pharmacodynamic characteristics, reports of bioequivalence (BE) / bioavailability problems, data on interactions between the drug and excipients and other data germane to the subject.All data reviewed in this monograph unambiguously support classification of sitagliptin as a BCS Class 1 drug. In light of its broad therapeutic index and lack of severe adverse effects, the clinical risks associated with moderately supraoptimal doses were deemed inconsequential, as were the risks associated with moderately suboptimal doses. Taking all evidence into consideration, it was concluded that the BCS-based biowaiver can be implemented for solid IR oral drug products containing sitagliptin phosphate monohydrate, provided (a) the test product is formulated solely with excipients commonly present in solid IR oral drug products approved in ICH or associated countries and used in amounts commonly applied in this type of product, (b) data in support of the BCS-based biowaiver are obtained using the methods recommended by the WHO, FDA, EMA or ICH and (c) the test product and the comparator product (which is the innovator product in this case) meet all in vitro dissolution specifications provided in the WHO, FDA, EMA or ICH guidance.

Impact of Zinc Stress on Biochemical and Biophysical Parameters in Coffea Arabica Seedlings

Zinc is an essential micronutrient for the healthy development of plants, since its insufficient and supraoptimal doses can disrupt the metabolism and biomass production. We aimed to investigate the physiological responses of coffee seedlings to Zn deficiency and excess. Six-month-old seedlings were transferred to plastic pots containing a nutrient solution. The treatments were control (0.03 ppm), zinc deficiency (0.00 ppm), and zinc excess (0.12 ppm). The evaluations were performed in leaves and roots at the beginning of the treatments and after 30 and 60 d of treatments. Zn deficiency and excess increased the production of hydrogen peroxide, antioxidant enzymes activity, ascorbate, and lipid peroxidation contents. The imbalance in zinc nutrition reduced total chlorophyll content and increased carotenoids content throughout the experimental period. Lower biomass and proline accumulation were observed only for deficient seedlings at the end of the experiment. The characteristics analyzed showed that zinc deficiency caused greater damage to the Coffea arabica plants of (Catuai cultivar) than zinc excess.

Modulation of Polyamines during Grain Development under Different Concentrations of Nitrogen in Wheat

The polyamine (PAs), putrescine (Put), spermidine (Spd) and spermine (Spm) are small aliphatic amines that ubiquitous in all living organisms. PA metabolism in higher plants is involved in both biotic and abiotic stress responses, and also influenced by nutrient deficiency. Accumulated evidence suggests that in plants the cellular titers of PAs are affected by various nitrogenous compounds. Therefore, the present study analyzed the effects of different nitrogen levels viz. recommended doses of nitrogen (RDN, 120 kg N/ha), sub-optimal N dose (RDN −25%, 90 kg N/ha) and supra-optimal N dose (RDN +25%, 150 kg N/ha) on PA metabolism in grains of six wheat genotypes at 15 days post anthesis (DPA) and 30 DPA. The activities of polyamine synthesizing enzymes (arginine decarboxylase, ornithine decarboxylase), catabolizing (diamine oxidase, polyamine oxidase) and the PA content were increased at supra-optimal nitrogen dose as compared to RDN. Whereas at sub-optimal nitrogen dose, higher activity of polyamine catabolizing enzymes results in speeding up oxidation of various PAs to cope up with nitrogen deficiency in plant. In relation to PA content, Put was found to be higher at early stage whereas Spd and Spm were found to be higher towards mature stages of grain indicating the use of Put in grain filling process. Highly significant correlation was observed between PA metabolism, yield and nitrogen use efficiency at sub-optimal N dose as compared to supra-optimal dose.

A preliminary safety evaluation of polyhexamethylene guanidine hydrochloride.

Polyhexamethylene guanidine hydrochloride (PHMGH) is used worldwide as an antimicrobial agent with broad spectra of activity and also for treating pool water. This non-GLP preliminary study aims at investigating in a subchronic toxicity study possible effects at supra-optimal doses of this biocide. Both acute and subchronic toxicity studies were conducted. LD(50) for PHMGH was estimated to be 600 mg/kg (ie LC(50) 2 ml of 7.5% solution) when administered as a single dose by gavage via a stomach tube in accordance with the expected route of administration. The acute studies showed that the median lethal dose (LD(50)) of 600 mg/kg was accompanied by signs of neurotoxicity. Haematological and biochemical parameters of subchronic toxicity studies were non-significant. Subchronic doses of 0.006 mg/kg, 0.012 mg/kg and 0.036 mg/kg were administered. 20% of the animals at a dose of 0.006 mg/kg and 0.036 mg/kg showed mild degrees of hydropic changes in proximal tubules while 10% of animals at all the doses had their liver tissues showing local areas of mild pericentral hepatocytes degeneration. PHMGH did not produce any major organ defect with regard to the kidney, heart, and liver. The LD(50) was much higher than the recommended dosage by a factor of about 50,000. The recommended residual concentration is far less than the median lethal dose using rats as test subjects. These results could serve as a basis for investigating the full toxicological profile if it is to be used for the treatment of raw water to make it potable.

Antigen-Dependent Integration of Opposing Proximal TCR-Signaling Cascades Determines the Functional Fate of T Lymphocytes

T cell anergy is a key tolerance mechanism to mitigate unwanted T cell activation against self by rendering lymphocytes functionally inactive following Ag encounter. Ag plays an important role in anergy induction where high supraoptimal doses lead to the unresponsive phenotype. How T cells "measure" Ag dose and how this determines functional output to a given antigenic dose remain unclear. Using multiparametric phospho-flow and mass cytometry, we measured the intracellular phosphorylation-dependent signaling events at a single-cell resolution and studied the phosphorylation levels of key proximal human TCR activation- and inhibition-signaling molecules. We show that the intracellular balance and signal integration between these opposing signaling cascades serve as the molecular switch gauging Ag dose. An Ag density of 100 peptide-MHC complexes/cell was found to be the transition point between dominant activation and inhibition cascades, whereas higher Ag doses induced an anergic functional state. Finally, the neutralization of key inhibitory molecules reversed T cell unresponsiveness and enabled maximal T cell functions, even in the presence of very high Ag doses. This mechanism permits T cells to make integrated "measurements" of Ag dose that determine subsequent functional outcomes.

Effect of BSA dosing on 5-FU exposure among colorectal cancer patients depending on their gender and age.

3627 Background: 5-fluorouracil (5-FU) remains the cornerstone of colorectal cancer (CRC) therapy and its dosing is based on body surface area (BSA). Although convenient, BSA dosing disregards factors that impact 5-FU PK such as genotype, age, gender, etc. Thus, patients receiving the same BSA based dose show a wide range of 5-FU plasma levels (measured as AUC in mg · h/L), resulting in ineffective or toxic doses affecting therapy outcome. An optimal therapeutic AUC target range of 20-30 mg · h/L has been proposed. Methods: Plasma samples from the initial treatment cycle of 927 CRC patients who received 2,400 mg/m2 continuous infusion of 5-FU over 44-48 hours, with or without bevacizumab, were tested for 5-FU exposure using an immune-based assay (OnDose). AUC results were analyzed to evaluate gender and age effects. Results: There are 391 (42.2%) female and 536 (57.8%) male patients with age ranging from 17-93 years (mean/SD: 58.5/11.8). See table. These analyses indicate that in comparison to the proposed optimal AUC target range of 20-30 mg · h/L, females receive supra-optimal doses compared to males (p=0.0083). Age also affects the 5-FU AUC (p=0.0002), with younger patients more likely to receive suboptimal doses than older patients. Conclusions: BSA dosing is an unreliable indicator of exposure and may lead to under dosing in males and younger patients, and overdosing in females and older patients, potentially resulting in corresponding diminished efficacy or increased toxicity. Data suggest that therapy could be optimizedby 5-FU dose adjustment in subsequent cycles based on PK monitoring so that AUC values will converge towards the target range irrespective of gender or age. A large clinical trial is in progress to validate these findings. [Table: see text]

BSA dosing and suboptimal 5-FU exposure among colorectal cancer patients of varying gender and age.

579 Background: 5-Fluorouracil (5-FU) remains the cornerstone of colorectal cancer (CRC) therapy and its dosing is based on body surface area (BSA). Although convenient, BSA dosing disregards factors that impact 5-FU PK such as genotype, age, gender, etc. Thus, patients receiving the same BSA based dose show a wide range of 5-FU plasma levels (measured as AUC in mg·h/L), resulting in ineffective or toxic doses affecting therapy outcome. An optimal therapeutic AUC target range of 20-30 mg·h/L has been proposed. Methods: Plasma samples from the initial treatment cycle of 927 CRC patients who received 2400 mg/m2 continuous infusion of 5-FU over 44-48 hours, with or without bevacizumab, were tested for 5-FU exposure using an immune-based assay (OnDose). AUC results were analyzed to evaluate gender and age effects. Results: There are 391 (42.2%) female and 536 (57.8%) male patients with age ranging from 17-93 years (mean/SD: 58.5/11.8). These analyses indicate that in comparison to the proposed optimal AUC target range of 20-30 mg·h/L, females receive supra-optimal doses compared to males (p=0.0083). Age also affects the 5-FU AUC (p=0.0002), with younger patients more likely to receive sub-optimal doses than older patients. Conclusions: BSA dosing is an unreliable indicator of exposure and may lead to under dosing in males and younger patients, and overdosing in females and older patients, potentially resulting in corresponding diminished efficacy or increased toxicity. Data suggest that therapy could be optimized by 5-FU dose adjustment in subsequent cycles based on PK monitoring so that AUC values will converge towards the target range irrespective of gender or age. A large clinical trial is in progress to validate these findings.

Calcineurin inhibition eliminates the normal inverted U curve, enhances acquisition and prolongs memory in a mammalian 3′-5′-cyclic AMP–dependent learning paradigm

The role protein phosphatase 2B (calcineurin, CaN) plays in learning and memory has received a significant amount of attention due to its promotion of the dephosphorylation of 3′-5′-cyclic AMP response element binding protein (CREB). Researchers have ascertained that overexpression of CaN is associated with memory retention deficits [Foster TC, Sharrow KM, Masse JR, Norris CM, Kumar A (2001) Calcineurin links Ca2+ dysregulation with brain aging. J Neurosci 21:4066–4073; Mansuy IM, Mayford M, Jacob B, Kandel ER, Bach ME (1998) Restricted and regulated overexpression reveals calcineurin as a key component in the transition from short-term to long-term memory. Cell 92:39–49], while CaN inhibition enhances learning and memory [Gerdjikov TV, Beninger RJ (2005) Differential effects of calcineurin inhibition and protein kinase A activation on nucleus accumbens amphetamine-produced conditioned place preference in rats. Eur J Neurosci 22:697–705; Ikegami S, Inokuchi K (2000) Antisense DNA against calcineurin facilitates memory in contextual fear conditioning by lowering the threshold for hippocampal long-term potentiation induction. Neuroscience 98:637–646]. The present study hypothesized that infusion of a CaN inhibitor (FK506) bilaterally into the olfactory bulbs of postnatal day 6 Sprague Dawley rat pups would prolong the duration of a conditioned odor preference and retard cyclic AMP response element binding protein dephosphorylation. A 2 mg/kg s.c. injection of isoproterenol (ISO, β-adrenoceptor agonist) was paired with a 10 min exposure to peppermint and subsequently an infusion of FK506. Immunohistochemistry for phosphorylated 3′-5′-cyclic AMP response element binding protein (pCREB) revealed that unilateral infusion of FK506 resulted in an amplification of phosphorylated CREB in the olfactory bulb 40 min after training compared with saline-infused bulbs. Pups infused bilaterally with FK506 maintained a learned preference for peppermint 48, 72 and 96 h after training. CaN inhibition also modified the conventional inverted U curve obtained when ISO is used to replace stroking, as the unconditioned stimulus. When pups were infused with FK506, learning occurred with sub- and supra-optimal doses of ISO indicating that CaN overcomes non-optimal effects ISO may have on learning. We demonstrate that CaN inhibition can extend the duration of conditioned olfactory memory and may provide a target for memory prolongation that is superior to even phosphodiesterase inhibition observed in previous studies.

Effects of Auxins and 2,3,5-Triiodobenzoic Acid on Somatic Embryo Initiation from Norway Spruce Zygotic Embryos (Picea abies)

Embryonal-suspensor mass (ESM) initiation from zygotic embryo sections was not affected by explant orientation whatever the type of external auxin used. Thus, polar auxin transport might not be directly involved in the control of somatic embryo formation. Application of 40 µM 2,3,5-triiodobenzoic acid (TIBA) suppressed ESM initiation in hypocotyl sections. This effect of TIBA mimicked that of a supraoptimal dose of α-naphtaleneacetic acid suggesting a detrimental effect of fast internal auxin accumulation on ESM initiation.

Pertussis toxin alters the innate and the adaptive immune responses in a pertussis-dependent model of autoimmunity

Pertussis toxin (PTX) is used to promote development of autoimmune diseases. The mechanism(s) are still incompletely understood. We dissected the innate and adaptive immune responses in a PTX-dependent model of autoimmune retinal disease, experimental autoimmune uveoretinitis (EAU), a Th1-driven disease of the neural retina elicited in F344 rats with a peptide derived from the retinal antigen interphotoreceptor retinoid binding protein (IRBP). Our results showed that optimal doses of PTX led to strongly increased innate cytokine responses, followed by enhanced adaptive Th1 immunity and disease. At supraoptimal doses of PTX, EAU was suppressed, the animals exhibited persistent lymphocytosis and had an inhibited chemotactic response to chemokines. We suggest that the suppressive effect of PTX at supraoptimal doses is due to inhibition of lymphocyte emigration from the blood into the target tissue, secondary to inhibition of Gi-protein-coupled chemokine receptor signaling, that persists into the effector phase of disease.

Inhibition of human T-cell responses by allergen peptides.

Of the many significant advances in the field of immunology that have occurred in the last 30 years arguably the most important, at least from a T-cell biologists point of view, has been the definition of major histocompatibility complex (MHC) restriction1 and the crystal structure of human leucocyte antigen (HLA) molecules.2–4 These demonstrations have enabled detailed study of the way in which T cells recognize antigen and also how this process differs from that in B cells. With a few notable exceptions, production of specific immunoglobulin by B cells is T-cell dependent. Furthermore, recruitment of non-lymphoid effector cells into areas of inflammation is a process largely marshalled by the T lymphocyte. It follows therefore that inhibition of T-cell function may have beneficial outcomes in situations in which detrimental immune responses occur and give rise to pathology. Suppression of T-cell function has been achieved with the use of pharmacological agents, such as glucocorticosteroids and cyclosporin, and more recently with biological agents, such as monoclonal antibodies directed against CD3 and CD4. Whilst achieving the desired aim of immunosuppression, these approaches suffer from serious weaknesses, the most obvious of which is a lack of specificity for the antigen(s) which drive the inflammatory process. The same may be said to be true of other therapeutic approaches currently being developed which aim to neutralize the effects of individual mediators in the inflammatory cascade. Here, a notable success has been the use of monoclonal antibodies to tumour necrosis factor (TNF) to treat patients with rheumatoid arthritis.5 However, the long-term consequences of removing individual mediators remain to be seen. Of concern is the recent report of subjects receiving anti-TNF therapy developing a lupus-like syndrome thought to be a direct result of the therapy itself.6 The challenge of introducing specificity into strategies aimed at modulating T-cell responses is one that has been met with considerable success in animal models by the use of peptide epitopes from the antigen in question. Peptide-induced tolerance has been demonstrated in models of experimental autoimmune encephalomyelitis (EAE),7,8 collagen-induced arthritis9 and, more recently, in models of allergic disease. Briner and colleagues sensitized mice to the cat allergen Fel d I and subsequently demonstrated the ability of allergen-derived peptides to inhibit T-cell cytokine and antibody production.10 Hoyne and colleagues demonstrated the ability of peptides from the house dust mite allergen Der p II to down-regulate T-cell and antibody responses to challenge with intact protein and also to prevent sensitization by prior administration.11,12 Bauer administered a dominant T-cell epitope of Bet v I to CBA/J mice either prior to or following sensitization with the whole allergen. No change in antibody isotype was observed but T-cell proliferative responses were inhibited by both treatments.13 More recently, mice sensitized to bee venom allergen phospholipase A2 (PLA2), were treated by intranasal administration of a mixture of three long peptides spanning the entire molecule. A marked reduction in specific immunoglobulin E (IgE) was observed coupled with a decreased interleukin-4 (IL-4) to interferon-γ (IFN-γ) ratio. Pre-administration of peptide resulted in a failure to develop IgE sensitization to subsequent immunization with the whole molecule.14 In addition to animal models, the ability of high-dose peptides to modulate human T-cell responses has also been demonstrated. In vitro studies with human T cells were performed by Lamb and colleagues, who demonstrated the induction of antigen-specific non-responsiveness following the incubation of T-cell clones with supraoptimal doses of specific ligand in the absence of professional antigen-presenting cells.15 Collectively, these studies provided a logical basis for the translation of a peptide-based therapeutic approach in man.

Enhanced development of somatic embryos of Plantago ovata Forsk. By additives

Plantago ovata Forsk (commonly known as Isabgul) is an economically important medicinal plant. In the present investigation, in vitro plant regeneration of P. ovata was attempted through somatic embryogenesis. Casein hydrolysate and coconut water were used in different concentrations in Murashige and Skoog medium along with 1-naphthaleneacetic acid and N6-benzyladenine to increase the amount of callus and number of somatic embryos. Light and scanning electron microscopic studies followed the developmental stages of embryo formation. Results indicated that optimum concentrations of casein hydrolysate and coconut water are useful for promoting the growth of embryogenic cultures. However, a supra-optimal dose of casein hydrolysate and coconut water induced polyphenol synthesis and caused browning of callus and also eventual death of embryos. The use of additives such as coconut water and casein hydrolysate promotes large-scale production of P. ovata through in vitro somatic embryogenesis.

Effects of lorglumide and atropine on MgSO4-induced gallbladder emptying in conscious dogs

The aim of the study was to examine the possible involvement of cholecystokinin (by lorglumide) and cholinergic mechanisms (by atropine) in magnesium sulphate (MgSO4)-induced gallbladder contraction of conscious dogs. The gallbladder (GB) volume was determined by ultrasonography. The optimal dose of 80mg kg–1of MgSO4was determined from a MgSO4dose–response curve using doses of 10, 20 ,40, 80, 120mg kg–1. The largest dose of MgSO4was less effective than the optimal dose. Peak gallbladder contraction (32 per cent) was achieved at 30 minutes. Atropine (50μg kg–1s.c.) or lorglumide (1mg kg–1p.o.) fully prevented GB contraction. In conclusion, supraoptimal doses of MgSO4have a diminishing effect. The sustained contraction of the gallbladder in response to the optimal dose of MgSO4can be explained by an additive effect of the cholecystokinin release and a cholinergic trigger mechanism. Ultrasonography and MgSO4stimulation proved to be a valuable technique for examination of gallbladder motility.

Effect of chorionic gonadotropin on the regulation of the functional activity of antigen-specific T-suppressors

Effects of chorionic gonadotropin (CG) on the functional activity of antigen-specific T-suppressors generated in CBA mice on day 14 by supraoptimal dose of thymus-dependent antigen were studied. The activity of T-suppressors was assessed by the level of antibody-producing (ABP) cells forming in the organism of suppressor cell recipients immunized with the same antigen. CG was injected to intact and oophorectomized recipient mice or was directly incubated in a one-hour cell culture with antigenspecific suppressor cells which were then transplanted to intact female mice. CG in a dose of 40 or 200 IU did not influence the capacity of T-suppressors to suppress primary immune response in intact females. In oophorectomized animals the hormone statistically reliably decreased the activity of T-suppressors, no matter what its dose were, and depressed the splenocyte activity. In a cell culture CG similarly depressed T-suppressor functional activity without influencing their homing.

Nitric oxide synthesis in rat peritoneal macrophages is induced by IgE/DNP complexes and cyclic AMP analogues. Evidence in favor of a common signaling mechanism.

The production of nitric oxide was studied in rat adherent peritoneal cells stimulated with preformed IgE/DNP-BSA complexes made of IgE obtained from a secreting hybridoma. Stimulation with complexes at equivalence induced both the production of NO and an increased expression of the mRNA of the inducible isoform of NO synthase (iNOS). Production of NO was also elicited by a rabbit polyclonal F(ab')2 anti-CD23 cross-reacting with rat CD23. Because IgE/DNP-BSA complexes did not elicit Ca2+ mobilization and genistein did not influence the production of NO, cyclic AMP was considered as an alternative signaling molecule. Combination of a suboptimal concentration of dibutyryl cyclic AMP and IgE/DNP-BSA complexes showed an additive effect on NO production, whereas this was not observed when the agonists were used at supraoptimal doses. The inhibitor of cyclic AMP-specific phosphodiesterase IV, rolipram, which acts on the enzyme isoform predominantly expressed in inflammatory cells, also induced the production of NO. Furthermore, IgE/DNP-BSA complexes increased intracellular levels of cyclic AMP. Taken together, these data indicate that stimulation of mononuclear phagocytes via the low-affinity receptor Fc epsilon RII or rising intracellular concentrations of cyclic AMP leads to an enhanced expression of iNOS. Evidence in favor of the involvement of cyclic AMP in the signaling pathway linked to Fc epsilon RII is provided by the effect of IgE/DNP-BSA complexes on intracellular cyclic AMP levels and by the additive effect produced by dibutyryl cyclic AMP on NO production elicited by IgE/DNP-BSA complexes.

Antioxidants

Free radicals and other “reactive oxygen species” (ROS) are formed continuously in the human body, both deliberately and by “accidents of chemistry.” Our endogenous antioxidant defenses are inadequate to completely prevent damage by ROS. Hence, diet-derived antioxidants may be of special importance in delaying or preventing the onset of diseases in which ROS are involved, such as cardiovascular diseases, chronic inflammatory diseases, neurodegenerative diseases, and some forms of cancer. Determining the optimal intake of antioxidant nutrients is one of the greatest challenges in the nutrition/free radicals field today, but the possibility of side effects from supraoptimal doses must not be ignored.

The in vivo effects of opioid peptides on the murine immune response

We have previously reported that met-enkephalin has dual immunomodulatory properties in vitro. We have continued this investigation using an in vivo system. In this study, Alzet miniosmotic pumps were loaded with either met-enkephalin, DTLET or FK 33-824 and were surgically implanted into BAF 1/J mice. Twenty-four hours after pump implantation, mice were challenged with sub-optimal, optimal or supraoptimal immunnizing doses of antigen. The immune response was assessed 4 or 5 days after primary immunization. FK 33-824, a met-enkephalin analogue, had no effect on the response of mice challenged with a suboptimal antigen dose. However, FK 33-824, at a pump concentration of 10 −3 M, suppressed the response against optimal challenge doses of antigen. At a pump concentration of 10 −8 M, FK 33-824 suppressed, enhanced or had no effect on the supraoptimal antigen dose-induced immune response. The supressive effect of FK 33-824 in mice immunized with either optimal or supraoptimal doses of antigen was blocked by naloxone. Met-enkephalin and its delta opioid receptor specific analogue, DTLET, had no effect on the immune response to optimal antigen immunization. These results indicate that FK 33-824 has in vivo immunomodulatory activity and provide and provide evidence that opioid peptides may either upregulate or downregulate the in vivo immune response depending on the strength of the response.

Superovulation of cattle with a recombinant-DNA bovine follicle stimulating hormone

A recombinant DNA-derived bovine follicle stimulating hormone (rbFSH) was utilized as a superovulatory agent in mature bovine females. Several aspects of utilization of this product were tested; dose and duration of treatment, repeated usage and a supraoptimal dose. Also, the ‘optimal’ dose was tested by several different investigators. Doses from 0.5 to 12 mg twice daily (BID) were tested over a range of 3–5 days duration. All doses greater than 0.5 mg BID for 4 days produced more than two ova/embryos (defined as a superovulatory response). A dose of 24 mg given for 3 days was more efficacious than lower doses with equal duration, but larger doses and longer durations of treatment did not produce a greater response ( P>0.05). Moreover, when a supraoptimal dose was given, the response was not different ( P>0.05) from the 24 mg dose. Embryo production was not altered when individual cows were superovulated more than once with the selected dose nor was subsequent reproductive performance affected. The above studies also demonstrate that a recombinant DNA-derived glycoprotein hormone (i.e. pure follicle stimulating hormone) can elicit a superovulatory response without exogenous luteinizing hormone (LH). The overall performance of rbFSH in these studies was similar to data previously reported for pituitary extracts.

Altered proliferative kinetics in PHA-activated human T-lymphocytes treated with the anti-HLA class I monoclonal antibody 01.65.

Anti-HLA class I monoclonal antibody (mAb) 01.65 inhibited phytohaemagglutinin (PHA)-induced human lymphocyte proliferation. The inhibitory effect was inversely correlated to the strength of the proliferative response. It was increased when lymphocytes were stimulated with suboptimal doses of PHA but it disappeared with supraoptimal doses. Proliferation inhibition was achieved by prolonging the cell cycle time and by slowing down its recruitment rate. The former effect was not restricted to the G1-phase but also included the S phase. These results support the idea that HLA class I molecules are important in the PHA-induced proliferation of human T-lymphocytes.