Different effects of the liver mitogens triiodo-thyronine and ciprofibrate on the development of rat hepatocellular carcinoma

Previous work has shown that treatment with thyroid hormone (T3) decreased the incidence of rat hepatocellular carcinoma (HCC). The present study was designed to determine whether the inhibitory effect of T3 on HCC development was limited to early steps of the carcinogenetic process or, whether a similar effect could also be exerted by starting T3 treatment at later stages. Hepatic nodules were induced in Fischer rats by a single dose of DENA, followed by a 2-week exposure of the animals to 2-AAF and partial hepatectomy. Rats were then divided into 3 groups: group 1 was maintained on basal diet: group 2 was fed a diet containing 4 mg/kg T3 for a week, every month/7 months, starting 9 weeks after DENA administration: group 3 was exposed to cycles of T3 starting 8 months after initiation. Results demonstrate that inhibition of HCC development was essentially similar in rats exposed to T3 starting either 9 weeks or 8 months after initiation (50% inhibition compared to control rats). We have previously shown that T3-induced nodule regression and HCC inhibition occurred in spite of its mitogenic effect. Therefore, we next wished to determine whether a similar antitumoral effect could be exerted by other liver mitogens, such as peroxisome proliferators. Rats exposed to the initiation-promotion protocol described previously, were subjected to 11 cycles of a T3 or a ciprofibrate-supplemented diet, each cycle consisting of 7 days/month: the incidence of HCC and lung metastases was determined 13.5 months after initiation. Results showed that although treatment with T3 strongly inhibited HCC development (only 31% of T3+ rats showed HCC vs 91% of controls), rats given ciprofibrate developed the same number of HCC as T3-untreated rats. In conclusion, the results of this study showed that the anticarcinogenic effect of T3 is maintained also when treatment begins late in the process, and its antitumoral property appears to be specific and may not be shared by other liver mitogens.     

Memory T-cell competition for bone marrow seeding

The presence in the bone marrow of memory CD8 T cells is well recognized. However, it is still largely unclear how T-cell migration from the lymphoid periphery to the bone marrow is regulated. In the present report, we show that antigen-specific CD4 T cells, as well as antigen-specific CD8 T cells, localize to the bone marrow of immunized mice, and are sustained there over long periods of time. To investigate the rules governing T-cell migration to the bone marrow, we generated chimeric mice in which the lymphoid periphery contained two genetically or phenotypically distinct groups of T cells, one of which was identical to the host. We then examined whether a distinct type of T cell had an advantage over the others in the colonization of bone marrow. Our results show that whereas ICAM1 and CD18 molecules are both involved in homing to lymph nodes, neither is crucial for T-cell bone marrow colonization. We also observed that memory-phenotype CD44high T cells, but not virgin-type CD44-/low T cells, preferentially home to the bone marrow upon adoptive transfer to normal young mice, but not to thymectomized old recipients where an existing memory T-cell pool precludes their free access. Thus, T-cell colonization of the bone marrow uses distinct molecules from those implicated in lymph node homing, and is regulated both by the properties of the T cell and by the competitive efficacy of other T cells inhabiting the same, saturable niche. This implies that the homing potential of an individual lymphocyte is not merely an intrinsic property of the cell, but rather a property of the lymphoid system taken as a whole.     

Hydrogen ion transport in the rabbit esophagus.

The lumen of the rabbit esophagus was perfused in vivo with solutions (one solution per esophagus) containing 0-160 mM HCl by a constant circulation technique for 5 h. During the 1st h, net H+ flux out of the lumen (efflux) was minimal at H+ concentrations of 80 mM or less, but increased linearly with increase in luminal H+ concentrations above 80 mM. After 3 h, the net H+ efflux increased proprtionately to increasing H+ concentrations above a threshold of 20 mM. At the 5th h a linear relationship between net H+ efflux and luminal concentration was seen at all concentrations. Histological damage accompanied increase in H+ efflux and correlated with luminal acid concentrations and duration of exposure. We conclude that the rabbit esophageal mucosa is essentially impermeable to H+ below a threshold concentration of 80 mM for up to 1 h of exposure. When exposure is prolonged, this threshold steadily decreases with time. The occurrence of passive H+ diffusion above threshold concentrations most probably results from an increase in mucosal permeability, possibly an initiating event in the genesis of esophagitis.     

Cytotoxic molecule expression and epithelial cell apoptosis in oral and cutaneous lichen planus

We evaluated the expression of T cell-restricted intracellular antigen (Tia-1), granzyme B, and perforin by lymphocytes and the degree of epithelial apoptosis in oral and cutaneous lichen planus (LP) in 51 untreated cases, including 27 oral LP (OLP) and 24 cutaneous LP (CLP) cases. The number of total dermal-positive lymphocytes in OLP and CLP was similar, indicating similar activity of the inflammatory process. Intraepithelial Tia-1-positive, perforin-positive, and granzyme B-positive lymphoid cells were more numerous in OLP than in CLP (P < .05). The epithelial cell apoptotic index (AI) was increased significantly in OLP (P < .05), particularly in erosive-atrophic variants. A linear correlation between AI and the mean +/- SEM number of intraepithelial and dermal perforin+ cells (6.85 +/- 2.44 and 27.48 +/- 10.19, respectively), per 10 high-power fields for OLP and for CLP (1.17 +/- 0.88 and 10.42 +/- 5.74, respectively), was found (intraepithelial, r = 0.50; dermal, r = 0.51; P < .01). These data suggest a pivotal role for perforin in triggering epithelial cell apoptosis. The differences of infiltrating cytotoxic cells and related AI observed in OLP and CLP are in keeping with the clinical behaviors that distinguish these LP variants.     

Employing a systematic approach to biobanking and analyzing clinical and genetic data for advancing COVID-19 research

Within the GEN-COVID Multicenter Study, biospecimens from more than 1000 SARS-CoV-2 positive individuals have thus far been collected in the GEN-COVID Biobank (GCB). Sample types include whole blood, plasma, serum, leukocytes, and DNA. The GCB links samples to detailed clinical data available in the GEN-COVID Patient Registry (GCPR). It includes hospitalized patients (74.25%), broken down into intubated, treated by CPAP-biPAP, treated with O₂ supplementation, and without respiratory support (9.5%, 18.4%, 31.55% and 14.8, respectively); and non-hospitalized subjects (25.75%), either pauci- or asymptomatic. More than 150 clinical patient-level data fields have been collected and binarized for further statistics according to the organs/systems primarily affected by COVID-19: heart, liver, pancreas, kidney, chemosensors, innate or adaptive immunity, and clotting system. Hierarchical clustering analysis identified five main clinical categories: (1) severe multisystemic failure with either thromboembolic or pancreatic variant; (2) cytokine storm type, either severe with liver involvement or moderate; (3) moderate heart type, either with or without liver damage; (4) moderate multisystemic involvement, either with or without liver damage; (5) mild, either with or without hyposmia. GCB and GCPR are further linked to the GCGDR, which includes data from whole-exome sequencing and high-density SNP genotyping. The data are available for sharing through the Network for Italian Genomes, found within the COVID-19 dedicated section. The study objective is to systematize this comprehensive data collection and begin identifying multi-organ involvement in COVID-19, defining genetic parameters for infection susceptibility within the population, and mapping genetically COVID-19 severity and clinical complexity among patients.Subject terms: Genetics research, Viral infection     

Behavioral and hormonal responses to stress in the newborn mouse: Effects of maternal deprivation and chlordiazepoxide

These studies investigated behavioral and hormonal responses to stress in developing mice. Experiment 1 examined the effects of 24-hr maternal deprivation on corticosterone (CORT) secretion and ultrasonic vocalization (UVZ) rate in 4-, 8-, and 12-day-old mice. At these ages, exposure to a novel environment resulted in minimal changes in CORT secretion. Maternal deprivation increased pups′ CORT secretion in an age-dependent fashion but did not affect their UVZ rate. The aim of experiment 2 was to test the effects of cholordiazepoxide (CDP), an anxyolytic compound, on CORT secretion and UVZ in both normally reared and in maternally deprived 8-day-old mice. CDP administration elevated CORT increases in deprived (DEP) animals. CDP affected UVZ only in nondcprived (NDEP) animals: UVZ ratewas decreased by high CDP doses Overall, these findings demonstrate that the infant mouse shows a period of stress hyp9oresponsiveness similar to the rat and that maternal presence contributes to inhibit adrenocorticalactivity. CDP administration, butnot novelty exposure, increased CORT secretion in 8-day- old normally reared mice suggesting that during the stress hyporesponsive period, the HPA axis is capable of responding only to specific stimuli. Changes in HPA axis activity and UVZ rateresulting from maternal deprivation and/or CDP challenge do not seem to be directly related. ©1994 John Wiley & Sons, Inc.     

Changes in EEG activity and hypothalamic temperature as indices for non-REM sleep to REM sleep transitions

A shift of physiological regulations from a homeostatic to a non-homeostatic modality characterizes the passage from non-NREM sleep (NREMS) to REM sleep (REMS). In the rat, an EEG index which allows the automatic scoring of transitions from NREMS to REMS has been proposed: the NREMS to REMS transition indicator value, NIV [J.H. Benington et al., Sleep 17 (1994) 28-36]. However, such transitions are not always followed by a REMS episode, but are often followed by an awakening. In the present study, the relationship between changes in EEG activity and hypothalamic temperature (Thy), taken as an index of autonomic activity, was studied within a window consisting of the 60s which precedes a state change from a consolidated NREMS episode. Furthermore, the probability that a transition would lead to REMS or wake was analysed. The results showed that, within this time window, both a modified NIV (NIV(60)) and the difference between Thy at the limits of the window (Thy(D)) were related to the probability of REMS onset. Both the relationship between the indices and the probability of REMS onset was sigmoid, the latter of which saturated at a probability level around 50-60%. The efficacy for the prediction of successful transitions from NREMS to REMS found using Thy(D) as an index supports the view that such a transition is a dynamic process where the physiological risk to enter REMS is weighted at a central level.     

Site-directed ELISA with synthetic peptides representing the HIV transmembrane glycoprotein

Two partially overlapping 19 and 22 amino acids long peptides representing a highly immunogenic site of the transmembranous glycoprotein (gp41) of human immunodeficiency virus (HIV) were used as antigen in ELISA tests. The results of antibody determination with this assay were compared with those of three or more conventional ELISAs and Western blot (WB) tests and radioimmunoprecipitation assay. Twenty-six sera from patients with AIDS or LAS and from asymptomatic carriers of HIV infection all showed a pronounced reaction in the peptide ELISA as well as positive results with other tests. In contrast, 27 sera from laboratory workers and blood donors were negative by all tests. A group of 39 blood donor sera, which had shown false positive or ambiguous results in the ELISAs and sometimes in WB tests employed for confirmation, also were negative in all cases with the peptide ELISA. Consecutive samples collected from individuals with primary HIV infection were also analyzed. In 6 out of 9 cases, the peptide ELISA revealed an antibody response within one month after onset of clinical symptoms and sensitivity for antibody detection equaled that of other ELISA tests. Eight sera from five West African persons infected with HIV-related viruses did not react in the peptide ELISA, reflecting differences in properties of the envelope components. The peptide ELISA used in this study appears to represent a simple technique employing chemically synthesized antigen for accurate and sensitive estimation of antibodies to the HIV group of nontransforming human retroviruses.     

Telepathology for routine light microscopic and frozen section diagnosis

Telepathology (TP) uses telecommunication linkages to electronically capture, store, retrieve, and transmit images to distant sites. We assessed the feasibility of a dynamic real-time TP system for light microscopic (LM) diagnosis of anatomic pathology specimens, including frozen sections. Six pathologists, in 2 separate periods, read a set of 160 retrospectively retrieved slides (80 of which were frozen sections) by TP and LM. Reading times were recorded. Diagnoses were compared with the reference diagnosis (established by a group of 5 independent pathologists) and graded on a scale of 0 to 2 (2, correct; 1, incorrect but no clinical impact; 0, incorrect with clinical impact). Overall, LM was more accurate than TP compared with the reference diagnosis (score, 1.68 vs 1.54). There was no difference in accuracy between frozen section and paraffin-embedded tissue. Intraobserver agreement ranged from 82.5% to 88.2%. The average reading time was 6.0 minutes for TP and 1.4 minutes for LM. During the study, reading time decreased for TP but not for LM. These results show that despite marginally lower accuracy and longer reading times, TP isfeasible for routine light microscopic diagnosis, including frozen sections.     

IFNgamma and TNFalpha account for a pro-clonogenic activity secreted by activated murine peritoneal macrophages

In the present study, we found that murine peritoneal macrophages elicited by BCG or Listeria monocytogenes release into the media an activity capable of stimulating the lung colonization as well as the expression of MHC class I antigens in B16 melanoma cells. A similar activity has previously been found in media conditioned by Corynebacterium parvum-elicited macrophages. Analysis by gel filtration chromatography of media conditioned by Corynebacterium parvum-, BCG- or Listeria monocytogenes-elicited macrophages revealed that the material responsible for the pro-clonogenic activity concentrated in chromatographic fractions corresponding to molecular weights (25 to 52 kDa) which are characteristic of certain cytokines. Thus, we challenged the various macrophage-conditioned media with polyclonal antibodies against IFNγand TNFα, and found that the macrophage pro-clonogenic activity was completely abolished in the presence of anti-IFNγantibodies, but only partially inhibited by anti-TNFαantibodies. This finding suggests a cooperative participation of the two cytokines to the pro-clonogenic activity of the media conditioned by Corynebacterium parvum-, BCG- or Listeria monocytogenes-elicited macrophages. This revised version was published online in July 2006 with corrections to the Cover Date.