Detection of recombinant and endogenous mouse melatonin receptors by monoclonal antibodies targeting the C‐terminal domain

Melatonin receptors play important roles in the regulation of circadian and seasonal rhythms, sleep, retinal functions, the immune system, depression, and type 2 diabetes development. Melatonin receptors are approved drug targets for insomnia, non‐24‐hour sleep‐wake disorders, and major depressive disorders. In mammals, two melatonin receptors (MTRs) exist, MT₁ and MT₂, belonging to the G protein‐coupled receptor (GPCR) superfamily. Similar to most other GPCRs, reliable antibodies recognizing melatonin receptors proved to be difficult to obtain. Here, we describe the development of the first monoclonal antibodies (mABs) for mouse MT₁ and MT₂. Purified antibodies were extensively characterized for specific reactivity with mouse, rat, and human MT₁ and MT₂ by Western blot, immunoprecipitation, immunofluorescence, and proximity ligation assay. Several mABs were specific for either mouse MT₁ or MT₂. None of the mABs cross‐reacted with rat MTRs, and some were able to react with human MTRs. The specificity of the selected mABs was validated by immunofluorescence microscopy in three established locations (retina, suprachiasmatic nuclei, pituitary gland) for MTR expression in mice using MTR‐KO mice as control. MT₂ expression was not detected in mouse insulinoma MIN6 cells or pancreatic beta‐cells. Collectively, we report the first monoclonal antibodies recognizing recombinant and native mouse melatonin receptors that will be valuable tools for future studies.     

Establishment and characterization of a chronic infectious mononucleosislike syndrome in common marmosets

Epstein-Barr virus (EBV) was inoculated into two species of marmosets. Successful infection was established in the majority of the animals of one species, Callithrix jacchus, as evidenced by the development of high, persistent levels of antibody against virus-specific capsid and early nonstructural proteins. Antibodies also were produced against the major membrane antigen and, in some animals, against EBV nuclear antigen (EBNA) 2 but not against EBNA 1. This is the antibody profile normally noted in individuals with chronic infectious mononucleosis (IM). EBV-induced lymphoproliferation was not seen, and EBV-specific proteins were not detected in the peripheral blood lymphocytes of infected animals. Hence, EBV infection in C. jacchus apparently does not generally include extensive B-cell involvement. However, the marmosets clearly are useful as a model for EBV primary infection and also possibly for chronic IM.     

Multiple phenotypic divergence of mammary adenocarcinoma cell clones.

We have shown that, with in vitro passage, subclones derived from clonal cell populations of 13762NF mammary adenocarcinoma undergo phenotypic drift and diversification in their cellular properties. Here we examine whether phenotypic divergence of 13762NF cell clones extends to therapeutic treatments used in eliminating mammary tumors and whether the apparent rates of phenotypic divergence vary for different treatments. Six subclones isolated from low passage clone MTF7 (T11 l; tissue culture passage 11) cells were compared to a similar number of subclones isolated from high passage clone MTF7 (T35; tissue culture passage 35) cells. Subclones derived from clone MTF7 (TI l) were relatively homogeneous (not significantly different) in their inherent sensitivities to ionizing radiation, extrapolation coefficients and quasithreshold dose values (D_o = 1·61–1·99 Gy; n=0·89–3·42; D_q = 0–2·34). When the MTF7 (Tll) subclones were examined for their sensitivities to 45°C hyperthermic treatment, the inherent sensitivities and dose-response curve parameters (D_o = 5·24–10·05 min; n = 1·08–10·47; D_q = 0·78–12·31) were heterogeneous (significantly different). In addition, the MTF7 (T1 l) subclones were heterogeneous (significantly different) in their sensitivities and dose-response curve parameters to 5-fluoro-2-deoxyuridine (FUdR) treatment (slope= –0·70 to –1·59; y-intercept = 1·31 × 10² to 47·80 × 10²). The LD₅₀ values for FUdR ranged from 14–150 nm for the MTF7 (T11) subclones. At high passage MTF7 (T35) subclones were heterogeneous in their dose-response parameters to ionizing radiation (D_o = 1·17–2·05 Gy; n = 0·80–41·18; D_q = 1·79-\24·94), hyperthermia (D_o = 3·57–6·32 min; n = 2·08–13·54; D_q = 3·68–9·30) and FUdR (slope= –0·77 to –0·93; y-intercept = 4·64 × 10² to 8·83 × 10²; LD₅₀ = 50–160nm). The results indicate that clonal cells diverge for distinct phenotypic properties at differing rates to form heterogeneous cell populations with unique sensitivities to various therapeutic treatments.     

Prophylaxis and treatment of experimental lung metastases in mice after treatment with liposome-encapsulated 6-O-stearoyl-N-acetylmuramyl-L-α-aminobutyryl-D-isoglutamine

A new lipophilic muramyl dipeptide analog, 6-O-stearoyl-N-acetylmuramyl-L--aminobutyryl-D-isoglutamine, when incorporated in liposomes, was effective in both the prevention and eradication of experimental pulmonary metastases in mice. Multilamellar vesicles composed of synthetic phospholipids (phosphatidylglycerol and phosphatidylcholine) containing saturated myristoyl or unsaturated dioleoyl acyl chains were found to potentiate the antimetastatic activity of this glycopeptide. Prophylactic and therapeutic efficacy was observed against the three murine tumors tested: FSa, an immunogenic fibrosarcoma; NFSa, a nonimmunogenic fibrosarcoma; and B16 melanoma. Neither the administration of empty liposomes or free glycopeptide, nor their coadministration, had a significant antimetastatic effect. This approach is promising for the therapy of cancer metastases in humans, particularly in the prevention of metastatic seeding and in the treatment of micrometastases.This is contribution No. 180 from the Institute of Bio-Organic Chemistry, Syntex Research.     

Increase in radiosensitivity of lung micrometastases by hyperbaric oxygen

Four-day-old artificial pulmonary micrometastases of two murine fibrosarcomas, designated FSA and NFSA, showed increased sensitivity to ionizing radiation by a factor of 1·13 when animals were exposed to hyperbaric oxygen breathing before and during irradiation, implying the presence of hypoxia in the micrometastases. At the time of irradiation the diameter of FSA and NFSA metastases was smaller than 200 and 100m, respectively, which, on the basis of oxygen diffusion, could not be responsible for hypoxia. It is assumed that hypoxia of micrometastases is passive, reflecting the radiobiological hypoxia of lung tissue that could exist under normal breathing conditions.     

Wi-Fi Technology and Human Health Impact: A Brief Review of Current Knowledge

An enormous increase in the application of wireless communication in recent decades has intensified research into consequent increase in human exposure to electromagnetic (EM) radiofrequency (RF) radiation fields and potential health effects, especially in school children and teenagers, and this paper gives a snap overview of current findings and recommendations of international expert bodies, with the emphasis on exposure from Wi-Fi technology indoor devices. Our analysis includes over 100 in vitro, animal, epidemiological, and exposure assessment studies (of which 37 in vivo and 30 covering Wi-Fi technologies). Only a small portion of published research papers refers to the “real” health impact of Wi-Fi technologies on children, because they are simply not available. Results from animal studies are rarely fully transferable to humans. As highly controlled laboratory exposure experiments do not reflect real physical interaction between RF radiation fields with biological tissue, dosimetry methods, protocols, and instrumentation need constant improvement. Several studies repeatedly confirmed thermal effect of RF field interaction with human tissue, but non-thermal effects remain dubious and unconfirmed.Key words: exposure to RF fields, e-school, radiofrequency, SAR     

Potentiation of tumor response to radiation or chemoradiation by selective cyclooxygenase-2 enzyme inhibitors

Cyclooxygenase-2 (COX-2) is an enzyme expressed primarily in pathologic states, such as inflammatory disorders and cancer, where it mediates prostaglandin production. Its overexpression is associated with more aggressive biologic tumor behavior and adverse patient outcome. Increasing evidence shows that agents that selectively inhibit COX-2 enhance tumor response to radiation or chemotherapeutic agents. This article gives an overview of some of this evidence. In addition, we describe new results showing that celecoxib, a selective COX-2 inhibitor, enhanced response of A431 human tumor xenografts in nude mice to radiation by an enhancement factor (EF) of 1.43 and to the chemotherapeutic agent docetaxel by an EF of 2.07. Celecoxib also enhanced tumor response when added to the combined docetaxel plus radiation treatment (EF = 2.13). Further experiments showed that selective COX-2 inhibitors enhanced tumor cell sensitivity to ionizing radiation, involving inhibition of cellular repair from radiation damage and cell cycle redistribution as mechanisms for some cell types. The results show that selective COX-2 inhibitors have the potential to improve tumor radiotherapy or radiochemotherapy, and this therapeutic strategy is currently under clinical testing.     

Senhance robot-assisted adrenalectomy: a case series

We present a case series of 12 consecutive robot-assisted adrenalectomies performed from May 2019 to March 2020 by a single surgeon experienced in laparoscopy using the novel Senhance robotic system. Eleven patients had primary aldosteronism due to an adrenal adenoma, diagnosed by means of endocrinological and radiological evaluation, and 1 had a benign adrenal cyst. The robotic adrenalectomy technique is described in detail. The mean procedure time was 165.1 minutes, with robotic docking time of 11.6 minutes and console time of 98.6 minutes. The mean estimated blood loss was 47 mL, and hospital stay duration was 4.5 days. There was 1 Clavien Dindo IIIB complication and 1 patient underwent conversion to laparoscopy. All patients with adenoma had complete biochemical remission after surgery. In conclusion, the Senhance robotic system is a safe and feasible platform for benign adrenal surgery in high-volume centers.

Laparoscopic adrenalectomy is the gold standard treatment of benign adrenal tumors because of the minimally invasive approach benefits. Although robot-assisted surgery was developed to enhance these benefits, adrenalectomy has not become a widespread robot-assisted procedure, probably due to a relatively low incidence of adrenal pathology. Published reports include a small number of patients, thus limiting conclusions regarding safety and feasibility of the procedure (1). The Da Vinci Surgical System was the only robotic platform in worldwide clinical use for two decades, practically becoming a synonym for robot-assisted surgery, but nowadays novel robotic platforms are emerging. The Senhance Surgical System, introduced into clinical use in 2013, is the first new platform that has proven to be safe and feasible in various surgical, gynecological, and urological procedures (2-6). This is the first detailed case-series of 12 consecutive robot-assisted adrenalectomies performed by using the new Senhance Surgical System reporting technical and clinical aspects of the procedure.