3,385 research outputs found

    Further steps of hepatic stimulatory substance purification

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    The hepatic stimulatory substance (HSS) extracted from weanling rat livers was purified 381,000-fold using chromatographic techniques including nondissociating polyacrylamide gel electrophoresis (nondenaturing PAGE). The activity of this highly purified HSS, named Acr-F4, was assessed in two in vivo models. In 40% hepatectomized rats, it produced a fivefold increase in the proliferative rate normally seen following this partial hepatectomy. In Eck fistula dogs, the level of base increase in hepatocyte renewal was amplified threefold by an infusion of Acr-F4 (50 ng/kg/day). Acr-F4 had no influence on the regenerative response of the kidney following a unilateral nephrectomy or of the bowel following a 40% resection of the small bowel. On the basis of these findings, it can be concluded that HSS (Acr-F4) has a high biological activity and is organ specific. © 1991 Plenum Publishing Corporation

    Processing and initial comparison of PSR data from CAMEX-3 to SSM/I and TMI data

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    A multiband Polarimetric Scanning Radiometer (PSR) was integrated on a NASA DC-8 aircraft and flown from August through September of 1998 during the third Convection and Moisture Experiment (CAMEX-3). The PSR is a new conically-scanning imaging radiometer with channels at 10.7, 18.7, 21.5, 37.0 and 89.0 GHz, including both vertical and horizontal polarizations at each of these frequencies. These channels correspond to several key sensing bands of the DMSP (Defense Meteorological Satellite Program) SSM/I (Special Sensor Microwave Imager) and the NASA TRMM (Tropical Rainfall Measuring Mission) TMI (TRMM Microwave Imager). The PSR was developed by Georgia Institute of Technology and the NOAA Environmental Technology Laboratory and is the first airborne imaging radiometer to provide a research quality dataset of high spatial resolution multiband polarimetric microwave imagery within and around a hurricane. The authors describe the processing and calibration of the PSR CAMEX-3 dataset. They also provide a qualitative analysis and comparison of the PSR imagery to the SSM/I and TMI with specific regard to the spatial structure of a hurricane eyewall and surrounding rainbands.Peer ReviewedPostprint (published version

    Cell proliferation and oncogene expression after bile duct ligation in the rat: Evidence of a specific growth effect on bile duct cells

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    The proliferative response of the rat liver was measured after temporary or permanent total biliary obstruction (BDO) and in different regions after selective ligation of the lobar ducts draining the right 60% of the hepatic mass. The results were compared with those after 70% partial hepatectomy (PH). Cell proliferation was assessed globally by measuring DNA synthesis and stratified to the separate cell populations with cytostaining techniques that allowed distinction of hepatocytes, duct cells, and nonparenchymal cells (NPCs). In selected experimental groups, gene expression was determined of transforming growth factor-β1 (TGFβ-1), prothrombin, c-erb-B2, transforming growth factor alpha (TGFα), human Cyclophilin (CyP), and 28S ribosomal RNA. The stimulation of a proliferative response to total BDO required obstruction for longer than 24 hours, but after this deligation did not switch off regeneration. In the first week after permanent BDO, there was progressive infiltration of NPCs, fibrous linkage of some portal areas, and a crescendo of DNA synthesis that was obvious at 24 hours, maximal at 48 hours, and back nearly to baseline at 6 days. At the 2-day mark, the bile duct cells had a 17-fold increase in proliferation, accompanied by a threefold to fourfold increase in hepatocyte renewal. Little or no increase in expression of TGFα or the hepatocyte-specific prothrombin gene was detectable in the first 48 hours, whereas levels of the oncogene c-erb-B2 that is associated with cholangiocarcinoma were expressed from 48 to 96 hours. Livers subjected to regional BDO with or without immunosuppressive treatment with FK 506 and cyclosporine had an inflammatory reaction only on the side with ligated ducts. DNA synthesis increased in both the obstructed and freely draining lobes to approximately half the level that occurred after total BDO. The proliferation of the obstructed side was similar to the mixed duct cell/hepatocyte response after total BDO, but this almost exclusively involved duct cells on the freely draining side. In contrast to the findings after BDO, livers after PH regenerated maximally at 24 hours rather than 48 hours, had a predominantly noninflammatory hepatocyte as opposed to duct cell response, and had marked expression of the prothrombin and TGFα genes but only weakly and late of c-erb-B2 messenger RNA. The results show that the liver responds as a whole and in a biologically intelligent way to the nature of the injury inflicted on any part of it. It further implies the presence of humoral communications and control networks that assure organ homeostasis and relate this to total body homeostasis. © 1995

    Application of T-Thesys Therapy in post-operative recovery in knee-surgical interventions: A case study

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    T-Thesys therapy is an innovative treatment that can be used even in the presence of recent injuries. For this reason, we studied the T-Thesys use in the post-operative phase of the anterior cruciate ligament (ACL) reconstruction of the knee. For our study, we selected 51 patients for ACL surgery, and we divided participants in two groups: the Experimental Group (EG) and the Control Group (CG). The EG consisted of 34 patients (age: 26.9 ± 7.65 years) who underwent T-Thesys therapy after surgery, while the CG included 17 patients (age: 26.7 ± 6.8 years) who was not subjected to T-Thesys therapy after surgery. T-Thesys therapy was performed on a daily basis and participants' parameters were monitored throughout the treatment. For the EG, we did not find any significant differences, however, subjective disorders seemed to disappear, almost entirely, at the seventh application. The CG showed no significant differences, even in the subjective disorders investigated. Therefore, the therapeutic treatment associated with T-Thesys therapy seems to not show any efficacy compared to the surgical treatment alone. However, from our findings emerged differences which tend to highlight a better clinical response, a faster recovery time, an improvement on the quality of life in patients, and, moreover, a better use of the National Health System resources

    The effect of estrogen and tamoxifen on hepatocyte proliferation in Vivo and in Vitro

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    We have previously shown that changes in estrogen‐hepatocyte interaction occur during liver regeneration. Following 70% hepatectomy, estrogen levels in the blood were elevated, the number of estrogen receptors in the liver was increased and there was an active translocation of estrogen receptors from the cytosol to the nucleus. The injection of tamoxifen, an estrogen antagonist, inhibits hepatocyte proliferation following partial hepatectomy. The administration of 1 μg tamoxifen per gm body weight at zero time or 6 hr after the operation resulted in a significant inhibition both of DNA synthesis and of the number of cells in mitosis. Injections of tamoxifen 12 hr or later after the operation had no effect. Concomitant injections of equimolar amounts of estrogen abolished the inhibition by tamoxifen. The effects of estrogen and tamoxifen were also tested on hepatocytes in primary culture. Estrogens in the presence of 5% normal rat serum stimulated hepatocyte DNA synthesis as determined by [3H]thymidine incorporation and the labeling index, whereas epidermal growth factor‐induced DNA synthesis in the absence of normal rat serum was strongly inhibited. Tamoxifen, in contrast, inhibited DNA synthesis of hepatocytes in the presence of 5% normal rat serum and reversed the stimulatory effect of estrogen in the same system. Attempts to elucidate the mechanism of tamoxifen inhibition in vitro indicated that one effect of tamoxifen is to prevent the amiloride‐sensitive Na+ influx necessary to initiate hepatocyte proliferation. Copyright © 1989 American Association for the Study of Liver Disease

    Hepatotrophic effects of FK506 in dogs

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    Portacaval shunt (Eck fistula) in dogs causes hepato- cyte atrophy and organelle disruption, as well as tripling of hepatocyte mitoses. After submitting dogs to this pro-cedure, FK506 was infused into the tied-off left portal vein. The size, anatomic quality, and replication of he- patocytes were enhanced in the portion of liver infused with FK506, with a significant spillover effect in the noninfused portion. These hepatotrophic qualities of FK506 may explain part of FK506’s efficacy for the treatment of chronic liver rejection. Also, the observa-tions support a trial with this drug for the treatment of autoimmune liver diseases because, in addition to turning off the immunologic genesis of such disorders, repair and regeneration of the damaged liver may be augmented. Finally, these hepatrophic qualities are part of an emerging spectrum of biologic effects caused by drugs that may modulate the enzyme cis-trans peptidyl-prolyl isomerase (PPIase), the principal constituent of the cy-tosolic binding sites of FK506, repamycin, cyclosporine, and presumably other immunosuppressive drugs as yet undiscovered.© 1991 by Williams & Wilkins

    Automatic Forecast of Intensive Care Unit Admissions: The Experience During the COVID-19 Pandemic in Italy

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    The experience of the COVID-19 pandemic showed the importance of timely monitoring of admissions to the ICU admissions. The ability to promptly forecast the epidemic impact on the occupancy of beds in the ICU is a key issue for adequate management of the health care system. Despite this, most of the literature on predictive COVID-19 models in Italy has focused on predicting the number of infections, leaving trends in ordinary hospitalizations and ICU occupancies in the background. This work aims to present an ETS approach (Exponential Smoothing Time Series) time series forecasting tool for admissions to the ICU admissions based on ETS models. The results of the forecasting model are presented for the regions most affected by the epidemic, such as Veneto, Lombardy, Emilia-Romagna, and Piedmont. The mean absolute percentage errors (MAPE) between observed and predicted admissions to the ICU admissions remain lower than 11% for all considered geographical areas. In this epidemiological context, the proposed ETS forecasting model could be suitable to monitor, in a timely manner, the impact of COVID-19 disease on the health care system, not only during the early stages of the pandemic but also during the vaccination campaign, to quickly adapt possible preventive interventions

    Drug resistance in B and non-B subtypes amongst subjects recently diagnosed as primary/recent or chronic HIV-infected over the period 2013–2016: Impact on susceptibility to first-line strategies including integrase strand-transfer inhibitors

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    Objectives To characterize the prevalence of transmitted drug resistance mutations (TDRMs) by plasma analysis of 750 patients at the time of HIV diagnosis from January 1, 2013 to November 16, 2016 in the Veneto region (Italy), where all drugs included in the recommended first line therapies were prescribed, included integrase strand transfer inhibitors (InNSTI). Methods TDRMs were defined according to the Stanford HIV database algorithm. Results Subtype B was the most prevalent HIV clade (67.3%). A total of 92 patients (12.3%) were expected to be resistant to one drug at least, most with a single class mutation (60/68–88.2% in subtype B infected subjectsand 23/24–95.8% in non-B subjects) and affecting mainly NNRTIs. No significant differences were observed between the prevalence rates of TDRMs involving one or more drugs, except for the presence of E138A quite only in patients with B subtype and other NNRTI in subjects with non-B infection. The diagnosis of primary/recent infection was made in 73 patients (9.7%): they had almost only TDRMs involving a single class. Resistance to InSTI was studied in 484 subjects (53 with primary-recent infection), one patient had 143C in 2016, a total of thirteen 157Q mutations were detected (only one in primary/recent infection). Conclusions Only one major InSTI-TDRM was identified but monitoring of TDRMs should continue in the light of continuing presence of NNRTI-related mutation amongst newly diagnosed subjects, sometime impacting also to modern NNRTI drugs recommended in first-line therapy

    Hepatocyte proliferation and gene expression induced by triiodothyronine in vivo and in vitro

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    Subcutaneous injections of hormone triiodothyronine in rats resulted in peak blood levels at 24 hr with return to baseline by 96 hr. The injections stimulated a liver regeneration response that resembled in timing and in magnitude of DNA synthesis (peak, 24 hr) that induced by 40% hepatic resection. The principal proliferation was of hepatocytes. Although there were some temporal differences from the gene expression of transforming growth factor‐α, transforming growth factor‐β, and c‐Ha‐ras that are known to follow partial hepatectomy, the overall profile of these changes was similar to those after partial resection. The effect was liver specific and could be reproduced three times with no diminution in response in the same animal with injections at 10‐day intervals. No response was detected in kidney or intestine. This effect in intact animals contrasted with the minimal ability of triiodothyronine to stimulate hepatocytes in culture. However, when the culture medium was enriched with epidermal growth factor, there was a dose‐related response to triiodothyronine. The totality of these experiments provides a preliminary basis for the creation with pharmacological techniques of an in vivo hyperplastic hepatic condition permissive of transfection of new genes, as an alternative to partial hepatectomy. Although triiodothyronine was the test agent used, other hepatic growth factors singly or in combination could be candidates for this purpose. (Hepatology 1994;20:1237–1241). Copyright © 1994 American Association for the Study of Liver Disease
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