Synthesis of gonadotropin-releasing hormone III analogs. Structure-antitumor activity relationships

Following the observation that the activity of gonadotropin-releasing hormone III (GnRH-III) in the suppression of growth of MDA-MB-231 and MCF-7 breast cancer cells surpasses that of GnRH and other analogs thereof, analogs of GnRH-III were synthesized to investigate the structural basis for the improved antitumor activity. Compounds synthesized include analogs with changes in the central sequence in which GnRH-III differs from GnRH and in the C- and N-terminal regions. The results indicate that a salt bridge between Asp6 and Lys8 stabilizes the active conformation of GnRH-III and show the importance of the Trp7. Replacement of the C-terminal Gly-NH2 with D-Ala-NH2 was not well tolerated, but replacement with ethylamide was. Replacement of pGlu1 with Ac-D-Trp appears to have a significantly deleterious effect on a unique conformation of GnRH-III which is responsible for its binding to the receptors on cancer cell lines and the resultant antitumor activity.

A specifically radiolabeled somatostatin analog with strong antitumor activity induces apoptosis and accumulates in the cytosol and the nucleus of HT29 human colon carcinoma cells

The new heptapeptide somatostatin analog TT-232 decreases proliferation of HT-29 human colon carcinoma cells in vitro by reducing mitotic and increasing apoptotic activity. We have synthesized and characterized a specifically tritium labeled 3H-Tyr3-TT-232 (30 Ci/mmol) to investigate the effect and the fate of this antitumor peptide on human colon tumor cells. 3H-labeled TT-232 could be detected on the cell surface, on cytoplasmic membranes and also in the nucleus of HT-29 cells, 1-6 h after the administration of 0.5 and 50 microg/mL [3H]TT-232. Binding and internalization of TT-232 to human colon tumor cells at a relatively high dose provide further evidence for the existence of low-affinity somatostatin receptors in such cells, which might mediate the apoptosis-inducing effect. Our data suggest the possible use of TT-232 in the treatment of human colon tumors.

[Challenge in modern intensive care: chronic critical illness - pathophysiology and therapeutic options]

The recent developments in intensive care have resulted in improved survival rates of patients treated with acute organ deficiency. As a consequence, the rate of those who survive the acute phase and subsequently require protracted organ support due to persisting organ dysfunction has been growing. Several survivors display chronic health status deterioration leading to prolonged rehabilitation or nursing, and repeated hospitalizations. The condition developed following the survival of the acute phase and requiring long-lasting intensive care is frequently termed as chronic critical illness (CCI). Several definitions exist, most of these are based on the number of ventilator days, or days of stay at the intensive care unit. Nevertheless, in spite of the initially heterogenous etiology of the acute illness, the complications associated with CCI, as well as the pathophysiological processes underlying these, are relatively uniform. This causes CCI to be a unique clinical syndrome characterized by the development of secondary infections, myopathy, central and peripheral neuropathy, and typical alterations of the hormonal and immune system functions. The outcome is heavily influenced by the frailty and comorbidities of the patient, in addition to the severity of the acute illness. The treatment of CCI patients presents a complicated task requiring multidisciplinary view and individualized therapeutic measures. Since the aging of the population and the continuously improving success rates in overcoming acute conditions also facilitate the development of CCI, the systematic overview of the underlying pathophysiological processes is pivotal for the optimization of the medical, nursing, social and economical burden presented by this syndrome. Orv Hetil. 2023; 164(18): 702-712.

Toxoplasma gondii seroprevalence and risk factors of cats in the Budapest area

This study aimed to survey the current distribution of Toxoplasma gondii (T. gondii) seropositivity within the cat population in Budapest area. Therefore, blood samples of 123 cats aged 0.5-18 years were collected. The measurements were performed by the commercial ID Screen® Toxoplasmosis Indirect Multi-species ELISA kit. The results indicate an overall 31.7% of seropositivity, which was significantly increasing with age. A correlation was also detected between the outdoor lifestyle and T. gondii infection. A significantly higher proportion of cats living outdoors were seropositive (38.8%) compared to those living indoor (18.6%) (P = 0.022). Finally, our study indicates a lower T. gondii seropositivity rate in cats compared to previous studies from Hungary, as well as from other European regions.

Assessment of the practical impact of adjusting beta-lactam dosages based on therapeutic drug monitoring in critically ill adult patients: a systematic review and meta-analysis of randomized clinical trials and observational studies

An estimated 70% of critically ill patients receive antibiotics, most frequently beta-lactams. The pharmacokinetic properties of these substances in this patient population are poorly predictable. Therapeutic drug monitoring (TDM) is helpful in making personalized decisions in this field, but its overall impact as a clinical decision-supporting tool is debated. We aimed to evaluate the clinical implications of adjusting beta-lactam dosages based on TDM in the critically ill population by performing a systematic review and meta-analysis of available investigations. Randomized controlled trials and observational studies were retrieved by searching three major databases. The intervention group received TDM-guided beta-lactam treatment, that is, at least one dose reconsideration based on the result of the measurement of drug concentrations, while TDM-unadjusted dosing was employed in the comparison group. The outcomes were evaluated using forest plots with random-effects modeling and subgroup analysis. Eight eligible studies were identified, including 1044 patients in total. TDM-guided beta-lactam treatment was associated with improved clinical cure from infection [odds ratio (OR): 2.22 (95% confidence interval (CI): 1.78-2.76)] and microbiological eradication [OR: 1.72 (CI: 1.05-2.80)], as well as a lower probability of treatment failure [OR: 0.47 (CI: 0.36-0.62)], but the heterogeneity of studies was remarkably high, especially in terms of mortality (70%). The risk of bias was moderate. While the TDM-guided administration of beta-lactams to critically ill patients has a favorable impact, standardized study designs and larger sample sizes are required for developing evidence-based protocols in this field.