Using early viral kinetics to predict antiviral outcome in response-guided pegylated interferon plus ribavirin therapy among patients with hepatitis C virus genotype 1

Background

HCV kinetics during treatment demonstrated strong association with the antiviral outcome of patients treated with pegylated interferon (Peg-IFN) plus ribavirin. However, the relationship between HCV kinetics and pre-treatment factors remains unclear.

Methods

Of 547 patients with HCV genotype 1 treated with Peg-IFN alfa-2b plus ribavirin, 401 completed the response-guided therapy and were assessed for per protocol analysis.

Results

The sustained virologic response (SVR) rate was 53 % for all patients, 60 % for those with genotype TT, and 19 % for those with genotype TG/GG according to IL28B (rs8099917) single nucleotide polymorphisms. The SVR rates increased with HCV decrease at week 4; 4 % (2/56) with <1 log₁₀ decrease, 13 % (7/56) with 1–2 log₁₀ decrease, 51 % (44/87) with 2–3 log₁₀ decrease, 64 % (56/87) with 3–4 log₁₀ decrease, 88 % (72/82) with more than 4 log₁₀ decrease but with detectable HCV RNA and 100 % (33/33) with undetectable HCV RNA (p < 0.001). Similarly, SVR rates increased step-by-step in proportion to HCV decrease in both IL28B TT and TG/GG groups, showing almost the same SVR rates for the same conditions. In multivariate analysis, age (p = 0.005) and the magnitude of HCV decrease at week 4 (p < 0.001) but not IL28B were associated with SVR. Advanced liver fibrosis (p = 0.004) and the magnitude of HCV decrease at week 4 (p < 0.001) but not IL28B were associated with non-response.

Conclusions

The magnitude of the HCV decrease at week 4 seems to be the most reliable marker for predicting antiviral outcome after starting Peg-IFN plus ribavirin therapy.     

Investigations on the etiology of sepsis by using experimental mouse model with leukocytopenia. 1. Influence of antibiotics

Investigation on the etiology of septicemia occurring among the immunocompromised patients was performed by using experimental model of the mouse with leukocytopenia. The ddY conventional mice of 4 weeks of age were inoculated with cyclophosphamide (CPM) intraperitoneally 3 to 5 times every other day with a dose of 3 mg/mouse once to make an agranulocytic status. Then, intraperitoneal administrations of various antibiotic regimens consisting of ampicillin (ABPC) alone, ABPC + ceftazidime (CAZ), ABPC + CAZ + cloxacillin (MCIPC), ABPC + CAZ + MCIPC + minocycline (MINO) and saline as a control to these immunosuppressed mice were begun once every day for 10 days after the second inoculation of CPM. The mortality rate of the mice given saline as a control was very high with a frequency of 43.3% and there were significant differences between the saline group and another antibiotic groups other than ABPC (p less than 0.01). On the other hand, the mortality rate of the group given APBC showed the highest rate of 70% and it was significantly higher than that of the saline control group (p less than 0.05). The main cause of most of the dead mice was septicemia due to P. aeruginosa and which were isolated from the feces of all these mice and serotype of the strains isolated from the heart blood and feces in the same host corresponded to each other. Moreover, intestinal bacterial flora in mice treated by saline and ABPC which highly showed Pseudomonas sepsis, was occupied dominantly by P. aeruginosa, although P. aeruginosa was not detectable from the experimental environments.(ABSTRACT TRUNCATED AT 250 WORDS)     

Structure-activity relationships of carbapenems to the antagonism of the antipseudomonal activity of other beta-lactam agents and to the beta-lactamase inducibility in Pseudomonas aeruginosa: effects of 1beta-methyl group and C-2 side chain.

The antagonism of the antipseudomonal activity of ceftazidime by meropenem (1a) was much less than those by imipenem (2a) and panipenem (2b). To reveal the major structural features of carbapenem compounds responsible for the antagonism, we investigated the structure-activity relationships of carbapenems to their antagonism of the antipseudomonal activity of ceftazidime and to their beta-lactamase-inducibility in P. aeruginosa. The antagonistic effect of 1a was less than that of desmethyl-meropenem (1b). Two other meropenem-analogues (3, 4), with the highly basic C-2 side chain, showed greater antagonistic effects than that of 1a, which has a weakly basic C-2 side chain. The beta-lactamase-inducibility of 1a in P. aeruginosa was lower than those of 2a, 1b and 4. These results indicated that the antagonism of the antipseudomonal activity of ceftazidime by carbapenems was due to the induction of beta-lactamase in P. aeruginosa. As a result of the study on the structure-activity relationships, we clarified that the introduction of a 1beta-methyl group and/or the reduction of the basicity (cationic character) of the C-2 side chain in carbapenem skeleton decreased the antagonistic effect of carbapenems on the antipseudomonal activity of ceftazidime resulted mainly from the decreasing the beta-lactamase inducibility.     

A non-enzymatic derived arachidonyl peroxide, 8-iso-prostaglandin F2 alpha, in cerebrospinal fluid of patients with aneurysmal subarachnoid hemorrhage participates in the pathogenesis of delayed cerebral vasospasm

We performed serial measurements of 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha), a non-enzymatic derived arachidonyl peroxide, in the cerebrospinal fluid (CSF) of 34 patients with subarachnoid hemorrhage (SAH). Patients were treated with open or endovascular surgery within 48 h of onset. Delayed cerebral vasospasm was verified by the presence of a low-density area on CT scan indicating focal cerebral infarction occurring after symptomatic delayed vasospasm. Concentrations of 8-iso-PGF2alpha in the CSF of 15 patients exhibiting delayed cerebral vasospasm were compared with those of 19 patients who did not exhibit vasospasm. The concentrations of 8-iso-PGF2alpha in the CSF of patients showing vasospasm were 42.4+/-37.1 pg/ml (mean+/-S.D., n=12) on Days 0-2, 66.4+/-41.0 pg/ml (n=14) on Days 3-5, 118.5+/-89.9 pg/ml (n=15) on Days 6-8, 86.2+/-70.2 pg/ml (n=11) on Days 9-11, 48.8+/-31.8 pg/ml (n=10) on Days 12-14, 27.8+/-20.1 pg/ml (n=7) after Day 20, while the concentrations in patients not showing vasospasm were 24.8+/-12.0 pg/ml (n=18) on Days 0-2, 25.7+/-15.2 pg/ml (n=19) on Days 3-5, 47.5+/-52.3 pg/ml (n=18) on Days 6-8, 56.7+/-72.0 pg/ml (n=13) on Days 9-11, 34.2+/-53.1 pg/ml (n=15) on Days 12-14, 20.1+/-18.2 pg/ml (n=10) after Day 20. CSF concentrations of 8-iso-PGF2alpha on Days 3-5 and Days 6-8 were significantly higher in patients showing vasospasm as compared to patients not showing vasospasm. CSF levels of 8-iso-PGF2alpha in patients showing vasospasm gradually increased in the days after onset of SAH and peaked on Days 6-8. Levels returned to normal after Day 20. These values on Days 3-5, Days 6-8, and Days 9-11 were significantly higher than the value after Day 20. Considering these data and the biological activities of 8-iso-PGF2alpha, such as development of inflammation, membrane perturbation and vasoconstriction, we conclude that 8-iso-PGF2alpha may play a role in delayed cerebral vasospasm after SAH.     

Investigations on the etiology of sepsis by using an experimental mouse model with leukocytopenia. 2. The role of the reticuloendothelial system in the etiology of bacteremia

It has been recognized by clinical data that most of sepsis occurring in the immunocompromised host are endogenous infection. In recent years, we have investigated the mechanism of these bacteremia and sepsis by experimental studies using neutropenic mice treated with cyclophosphamide. And we evidenced that most pathogens causing bacteremia originated in the intestinal flora of the host. It has been shown that bacteria causing bacteremia were divided into two main groups, causing systemic bacteremia and causing portal bacteremia. Pseudomonas aeruginosa and Morganella morganii belonged to the former, on the other hand, Escherichia coli, Enterobacter cloacae and some other bacteria belonged to the latter. In this study, we studied the role of the reticuloendothelial system (RES) in the etiology of bacteremia or sepsis, using various kinds of bacteria isolated from bacteremic mice. As a result, the following facts were revealed. 1. It was suggested that the low blood clearance rate of the bacteria was one of the great risk factor of systemic bacteremia, since the blood clearance rate of bacteria causing systemic bacteremia was significantly lower than those of bacteria causing portal bacteremia. 2. Bacteria in the blood were eliminated by the RES, mainly by the liver, and the level of bacterial clearance by the liver was relative to the type of bacteremia which was systemic or portal. 3. It was suggested that the bacterial clearance by the liver mainly reflected the phagocytosis by Kupffer cells, and especially the adherence of these cells to bacteria as the first step of phagocytosis.     

Trace eyeblink conditioning in decerebrate guinea pigs

We investigated the trace eyeblink conditioning in decerebrate guinea pigs to elucidate the possible role of the cerebellum and brainstem in this hippocampus-dependent task. A 350-ms tone conditioned stimulus was paired with a 100-ms periorbital shock unconditioned stimulus with a trace interval of either 0, 100, 250 or 500 ms. Decerebrate animals readily acquired the conditioned response with a trace interval of 0 or 100 ms. Even in the paradigm with a 500-ms trace interval, which is known to depend critically on the hippocampus in all animal species examined, the decerebrate guinea pigs acquired the conditioned response, which had adaptive timing as well as in the other paradigms with a shorter trace interval. However, it took many more trials to learn in the 500-ms trace paradigm than in the shorter trace interval paradigms, and the conditioned response expression was unstable from trial to trial. When decerebrate animals were conditioned step by step with a trace interval of 100, 250 and 500 ms, sequentially, they easily acquired the adaptive conditioned response to a 500-ms trace interval. However, the frequency of conditioned responses decreased after the trace interval was shifted from 250 ms to 500 ms, which was not observed after the shift from 100 ms to 250 ms. These results suggest that the cerebellum and brainstem could maintain the 'trace' of the conditioned stimulus and associate it with the unconditioned stimulus even in the 500-ms trace paradigm, but that the forebrain might be required for facilitating and stabilizing the association.     

Photoelectric dye-coupled polyethylene film as a prototype of retinal prostheses

Photoelectric dyes, which absorb light and convert photon energy to electric potentials, have been previously shown to stimulate retinal neurons in culture. In this study, a photoelectric dye was coupled to a polyethylene film surface and tested in vitro using retinal tissues from chick embryos at the 12-day embryonic stage, at which time outer segments of retinal photoreceptor cells have not yet developed. Carboxyl moieties were introduced to a polyethylene film surface by fuming nitric acid, and then a photoelectric dye, 2-[2-[4-(dibutylamino)phenyl]ethenyl]-3-carboxymethylbenzothiazolium bromide, was coupled to the film through amide linkage. Intracellular calcium elevation was observed with Fluo-4 in retinal tissues placed on the dye-coupled polyethylene film, in contrast to retinal tissues which had no contact with the film. The response was inhibited by calcicludine, a voltage-gated calcium channel blocker, and also by extracellular calcium depletion. The photoelectric dye, coupled to the polyethylene film surface, absorbed light under a dissecting microscope and stimulated neurons in retinal tissues, showing that the dye-coupled film could be used as a prototype of retinal prostheses.