In Vitro Effects of Tp5 Analogs on E-Rosette Formation and Cell Division

The effects of seventeen synthetic analogs of thymopentin (TP-5) have been studied in the active and azathioprine-inhibited E-rosette tests.

Thymopentin was gradually shortened from the C terminus to peptides and single amino acids. Thymopoietin 32-34 (Arg-Lys-Asp-RGH-0205-TP-3) (II) and thymopoietin 32-35 (Arg-Lys-Asp-Val-RGH-0206-TP-4) (I) were the most active peptides.

Dipeptide Arg-Lys produced significant stimulatory effect on azathioprine (ED₇₅) inhibited E-receptor. Treatment of azathioprine (ED₇₅-inhibited E-rosette forming cells (ERFC) with arginine or especially lysine increased the number of ERFC.

Some of TP-4 analogs decreased further the number of ERFC decreased by azathioprine ED₃₀. These “suppressive” peptides as well as TP-3 caused a partial arrest of K 562 cell proliferation up to 96 hours.

Results suggest that TP-5 is not the smallest active fragment of thymopoietins, since peptides (TP-3 and TP-4) exhibit similar or higher T-cell membrane activation on E-receptor. Arginine, lysine, and acidic aspartyl residue seem to be a necessary basic structure to produce a cumulative chemical signal on the activity of T-lymphocytes.     

Steroid withdrawal at 3 months after kidney transplantation: a comparison of two tacrolimus-based regimens

The 6 month prospective, randomized study compared the steroid-sparing potential of two tacrolimus-based regimens after renal transplantation. A total of 489 patients were randomized (1:1) to receive tacrolimus/mycophenolate mofetil (MMF)/steroids (n = 243; group Tac/MMF/S) or tacrolimus/azathioprine/steroids (n = 246; group Tac/Aza/S). At 3 months, steroids were tapered off in 267 (54.6%) patients free from steroid-resistant acute rejection and with serum creatinine concentrations <160 micromol/l. The incidence of biopsy-confirmed acute rejection at month 3 was lower in group Tac/MMF/S compared with group Tac/Aza/S (18.1% vs. 26.0%,P = 0.035). Moreover, more patients in the Tac/MMF/S group met the criteria for steroid withdrawal than in the Tac/Aza/S group (60.5% vs. 48.8%; P < 0.01). The incidence of acute rejection during months 4-6 was low in all groups, both for patients on steroid-free dual therapy (Tac/MMF: 2.7%, Tac/Aza: 0.8%) and for patients who continued steroid maintenance therapy (Tac/MMF/S: 3.5%, Tac/Aza/S: 7.1%). Moreover, kidney function was well preserved in steroid-free patients with month 6 median serum creatinine levels of 119.5 micromol/l (Tac/MMF), and 115.1 micromol/l (Tac/Aza). For patients who continued to receive steroids, month 6 median creatinine levels were 130.5 micromol/l (Tac/MMF/S) and 132.8 micromol/l (Tac/Aza/S). The criteria for the selection of patients to discontinue steroids were adequate. Both tacrolimus-based regimens allowed the safe discontinuation of steroids in low-risk patients at month 3. The Tac/MMF combination was superior in the prevention of acute rejections and more patients met the chosen criteria for steroid withdrawal.     

A randomized trial to evaluate compliance in terms of patient comfort and satisfaction of two pneumatic compression devices

PURPOSE: Venous thromboembolism (VTE) incidence can be substantially reduced with prophylaxis, which includes pneumatic compression device (PCD) use. METHODS: To determine whether patient comfort and satisfaction correlated to compliance in wearing PCDs, patients were randomly assigned to either of two effective calf-high PCDs. Education and handouts were provided to both groups. Patients were given a survey rating their comfort, satisfaction, and compliance. At the conclusion of the study, healthcare providers completed a questionnaire comparing both PCDs. RESULTS: A total of 65 patients participated. The main significant differences between groups were seen in the patient perceptions questionnaire for two items: "the device was hot" (p = .014) and "device made my legs sweat" (p = .029). The PCD that provided more comfort and satisfaction was worn for a greater amount of time, 85% vs. 81%, respectively. CONCLUSIONS: Results suggest that patients are more compliant with a PCD that promotes patient comfort when worn.     

Valganciclovir Inhibits Human Adenovirus Replication and Pathology in Permissive Immunosuppressed Female and Male Syrian Hamsters

Adenovirus infections of immunocompromised pediatric hematopoietic stem cell transplant patients can develop into serious and often deadly multi-organ disease. There are no drugs approved for adenovirus infections. Cidofovir (an analog of 2-deoxycytidine monophosphate) is used at times but it can be nephrotoxic and its efficacy has not been proven in clinical trials. Brincidofovir, a promising lipid-linked derivative of cidofovir, is in clinical trials. Ganciclovir, an analog of 2-deoxyguanosine, has been employed occasionally but with unknown efficacy in the clinic. In this study, we evaluated valganciclovir against disseminated adenovirus type 5 (Ad5) infection in our permissive immunosuppressed Syrian hamster model. We administered valganciclovir prophylactically, beginning 12 h pre-infection or therapeutically starting at Day 1, 2, 3, or 4 post-infection. Valganciclovir significantly increased survival, reduced viral replication in the liver, and mitigated the pathology associated with Ad5 infection. In cultured cells, valganciclovir inhibited Ad5 DNA replication and blocked the transition from early to late stage of infection. Valganciclovir directly inhibited Ad5 DNA polymerase in vitro, which may explain, at least in part, its mechanism of action. Ganciclovir and valganciclovir are approved to treat infections by certain herpesviruses. Our results support the use of valganciclovir to treat disseminated adenovirus infections in immunosuppressed patients.     

Metabolomic analysis of prostate cancer risk in a prospective cohort: The alpha‐tocopherol,beta‐carotene cancer prevention (ATBC) study

Despite decades of concerted epidemiological research, relatively little is known about the etiology of prostate cancer. As genome‐wide association studies have identified numerous genetic variants, so metabolomic profiling of blood and other tissues represents an agnostic, “broad‐spectrum” approach for examining potential metabolic biomarkers of prostate cancer risk. To this end, we conducted a prospective analysis of prostate cancer within the Alpha‐Tocopherol, Beta‐Carotene Cancer Prevention Study cohort based on 200 cases (100 aggressive) and 200 controls (age‐ and blood collection date‐matched) with fasting serum collected up to 20 years prior to case diagnoses. Ultrahigh performance liquid chromatography/mass spectroscopy and gas chromatography/mass spectroscopy identified 626 compounds detected in >95% of the men and the odds ratio per 1‐standard deviation increase in log‐metabolite levels and risk were estimated using conditional logistic regression. We observed strong inverse associations between energy and lipid metabolites and aggressive cancer (p = 0.018 and p = 0.041, respectively, for chemical class over‐representation). Inositol‐1‐phosphate showed the strongest association (OR = 0.56, 95% CI = 0.39–0.81, p = 0.002) and glycerophospholipids and fatty acids were heavily represented; e.g., oleoyl‐linoleoyl‐glycerophosphoinositol (OR = 0.64, p = 0.004), 1‐stearoylglycerophosphoglycerol (OR=0.65, p = 0.025), stearate (OR=0.65, p = 0.010) and docosadienoate (OR = 0.66, p = 0.014). Both alpha‐ketoglutarate and citrate were associated with aggressive disease risk (OR = 0.69, 95% CI = 0.51–0.94, p = 0.02; OR = 0.69, 95% CI = 0.50–0.95, p = 0.02), as were elevated thyroxine and trimethylamine oxide (OR = 1.65, 95% CI = 1.08–2.54, p = 0.021; and OR = 1.36, 95% CI = 1.02–1.81, p = 0.039). Serum PSA adjustment did not alter the findings. Our data reveal several metabolomic leads that may have pathophysiological relevance to prostate carcinogenesis and should be examined through additional research.     

Effect of treatment with LHRH analogs containing cytotoxic radicals on the binding characteristics of receptors for luteinizing-hormone-releasing hormone in MXT mouse mammary carcinoma

Binding capacities and apparent dissociation constants of receptors for luteinizing-hormone-releasing hormone (LHRH) were investigated in estrogen-independent MXT mammary cancers of untreated mice and after in vivo treatment with agonistic or antagonistic analogs of LHRH containing cytotoxic radicals: AJ-04 (agonist [d-Lys⁶]LHRH linked to methotrexate), T-98-{[d-Lys⁶]LHRH coupled to glutaryl-2-(hydroxmethyl)anthraquinone (G-HMAQ)} and T-121/B (LHRH antagonist T-147 containing two residues of G-HMAQ), which induced tumor growth inhibition. The effects were compared to LHRH agonist [d-Trp⁶]LHRH and carriers [d-Lys⁶]LHRH, LHRH antagonist T-147, as well as to methotrexate, G-HMAQ and surgical bilateral overiectomy. Analysis of the binding data revealed that in control tumors the interaction of¹²⁵I-[d-TRP⁶]LHRH was consistent with the presence of one class of saturable, specific, noncooperative, high-affinity and low-capacity binding sites. Chronic treatment of mice bearing MXT tumors with LHRH analogs AJ-04 and T-121/B carrying cytotoxic radicals, but not with T-98 produced significant down-regulation of membrane receptors for LHRH. The largest decrease in dissociation binding constant andB _max of receptors for LHRH was also found in animals treated with T-121/B. Specific, high affinity binding of¹²⁵I-labelled epidermal growth factor (EGF) was detected in the membranes from control and treated MXT tumors. Treatment with cytotoxic LHRH analogs, AJ-04, T-98 and especially with T-121/B, reduced maximal binding capacity of EGF receptors. Our results indicate that LHRH analogs carrying cytotoxic radicals retain their hormonal activity and inhibit tumor growth while inducing down-regulation of LHRH receptors. In addition, probably both components of the cytotoxic LHRH analog, peptide carriers and cytotoxic radicals, reduce the binding capacity of EGF receptors, which might be useful in the treatment of breast cancer.Abbreviations LHRH luteinizing-hormone-releasing hormone - EGF epidermal growth factor     

Inhibition of growth of experimental prostate cancer in rats by LH-RH analogs linked to cytotoxic radicals

The effects of hybrid cytotoxic LH-RH analogs, produced by linking anthraquinone or methotrexate to carrier LH-RH agonist [D-Lys⁶]LH-RH, were evaluated in Copenhagen-Fisher Fl rats bearing Dunning R-3327H prostate adenocarcinoma. The two cytotoxic LH-RH analogs T-98 [(D-Lys⁶)LH-RH coupled to glutaryl-2-(hydroxymethyl)anthraquinone (G-HMAQ)], and AJ-04 [(D-Lys⁶)LH-RH linked to methotrexate (MTX)], carrier [D-Lys⁶]LH-RH, or the free cytotoxic compounds MTX and G-HMAQ were administered from Alzet Osmotic minipumps for 7–8 weeks. The cytotoxic LH-RH analogs caused somewhat greater tumor growth inhibition than the carrier peptide, while anthraquinone or methotrexate alone, administered in equimolar doses, were ineffective. The inhibition of androgen sensitive organs (testes, ventral prostates, and seminal vesicles) was pronounced with both carrier and cytotoxic analogs, showing the latter to be fully hormonally active in suppressing the pituitary-gonadal axis. Histological changes were also evaluated. The inhibition of mitosis and the frequency of apoptosis were higher in tumors treated with AJ-04, T-98, [D-Lys⁶]LH-RH, or by castration than in those of controls. Serum hormone levels were lowered by both carrier peptide and cytotoxic analogs, LH being substantially depressed, and testosterone not detectable. These results and other findings indicate that LH-RH analogs containing cytotoxic radicals anthraquinone or methotrexate retain their hormonal activity after administration in vivo, and can effectively inhibit tumor growth. Extensive further studies are required on this new class of compounds, but apparent binding of cytotoxic LH-RH analogs to tumors such as prostate cancer, which have receptors for LH-RH, could greatly reduce peripheral toxicity of chemotherapeutic agents. This approach, based on targeted chemotherapy, might be of practical therapeutic importance for the management of advanced prostate cancers, which eventually relapse after palliative hormonal therapy. © 1993 Wiley-Liss, Inc.