Endoscopic and histopathological evaluation of collagenous colitis

Collagenous colitis (CC) is a well-known cause of chronic non-bloody diarrhea, especially in elderly women. CC is characterized histopathologically by an increase in the thickness of the subepithelial collagen layer to at least 10 μm, epithelial damage, and chronic inflammation of the lamina propria. Generally, the colonic mucosa in CC is macroscopically normal, although minor, non-specific abnormalities may be found. Due to the recent advancement of endoscopic and diagnostic technologies, however, microscopic mucosal abnormalities and specific longitudinal linear lacerations of the mucosa characteristic of CC have been identified. The association of CC with non-steroidal anti-inflammatory drugs and proton pump inhibitors has also been reported. Since definitive diagnosis of CC has to rely on pathologically documented collagen bands and mononuclear infiltration, the efficiency and precision of colonic biopsy need to be improved. Of the 29 CC patients that we have encountered at our institution, it was in 15 of 29 cases that the endoscopic finding that we performed a biopsy on was apparent. Our comparison of the endoscopic and histopathological findings of CC in the 15 patients showed that the mucosa frequently appeared coarse and nodular on the surface of the mucosa, which was also significantly thicker in collagen bands, demonstrating a strong correlation between collagen band formation and CC. Also, the coarse and nodular surface of the mucosa was most frequently seen affecting the proximal colon. The results suggest that endoscopic observation and biopsy of the proximal colon, where a coarse and nodular surface of the mucosa is often found, may be useful for confirmation of the diagnosis in patients with suspected CC.     

Reducing Peg-IFN doses causes later virologic response or no response in HCV genotype 1 patients treated with Peg-IFN alfa-2b plus ribavirin

Background

The timing to the first undetectable hepatitis C virus (HCV) RNA level is strongly associated with sustained virologic response in pegylated interferon (Peg-IFN) plus ribavirin combination therapy for patients with chronic hepatitis C (CH-C) with genotype 1. This study was conducted to clarify the impact of drug exposure to Peg-IFN on the timing of HCV RNA negativity in Peg-IFN plus ribavirin combination therapy for CH-C patients with genotype 1.

Methods

A total of 1409 patients treated with Peg-IFN alfa-2b plus ribavirin were enrolled and classified into four categories according to the Peg-IFN dosage. Furthermore, 100 patients were extracted from each Peg-IFN dosage category to adjust for characteristic factors, using the propensity score method.

Results

Peg-IFN exposure was dose-dependently associated with the timing of HCV RNA negativity (p????0.001). The HCV RNA negative rate at week 4 decreased from 12% with a Peg-IFN dose of >1.5???g/kg/week to 1?C3% with a dose of <1.5???g/kg/week (p????0.001), and at week 12 the rate had decreased from 44% with a dose of ??1.2???g/kg/week to 18% with a dose of <1.2???g/kg/week (p?=?0.001). Treatment failure (patients without a 1-log decrease of HCV RNA at week 4 or a 2-log decrease of HCV RNA at week 12, or positive at week 24) was found in 54?C66% of patients given <1.2???g/kg/week (p????0.001), and these patients accounted for 64% of the non-responders.

Conclusions

The timing of HCV RNA negativity depends significantly on the Peg-IFN dose. Reducing the Peg-IFN dose can induce a later virologic response or non-response in HCV genotype 1 patients treated with Peg-IFN plus ribavirin.     

Purkinje cell activity during learning a new timing in classical eyeblink conditioning

During classical eyeblink conditioning, animals acquire adaptive timing of the conditioned response (CR) to the interstimulus interval (ISI) between the conditioned stimulus (CS) and the unconditioned stimulus (US). To investigate this coding of the timing by the cerebellum, we analyzed Purkinje cell activities during acquisition of new timing after we shifted the ISI. Decerebrate guinea pigs were conditioned to an asymptotic level of learning using a delay paradigm with a 250-ms ISI. A 350-ms tone and a 100-ms electrical shock were used as the CS and US, respectively. As reported previously in other species, Purkinje cells in the simplex lobe exhibited three types of responses to the CS: excitatory, inhibitory, or a combination of the two. After we increased the ISI to 400 ms, the frequency of the CR stayed at an asymptotic level, but the latency of the CR peak became gradually longer. Two types of cells were observed, based on changes in the nature of their response to the CS; one changed its type of response in parallel with learning the new timing, while the other did not. There was no correlation between the type of response before and after we changed the ISI. In some cells, the peak latency of activities became longer or shorter, while the type of response did not change. These results suggest that some Purkinje cells code the timing of the CR, but do not play a consistent role in shaping the CR over a range of ISIs.     

Morphological alterations of submandibular glands caused by cisplatin in the rat

Cisplatin is a platinum-containing antineoplastic agent, widely used in the treatment of various malignant neoplasms including head and neck cancer. In this study we examined ultrastructural changes of rat submandibular glands (SMGs) after cisplatin treatment. Male Wistar rats aged 8 weeks were used in the experiments. Cisplatin was injected intraperitoneally into the rats (5 mg/kg/day) for three consecutive days. After 1, 3, 5, and 7 days, the SMGs were removed and observed under an electron microscope. The terminal portion of the SMG is seromucosal. Acinar cells contained a parallel array of rough-surfaced endoplasmic reticulum in the basal cytoplasm, and the apical cytoplasm was filled with homogeneous secretory granules. Vacuolation of cells was observed on the first day after cisplatin treatment. On the third and fifth days, the rough-surfaced endoplasmic reticulum showed an irregular arrangement. Mitochondrial swelling, and the presence of autophagolysosomes was also confirmed. On the seventh day, the damage to organelles began to decrease and the SMG exhibited a tendency towards improvement.     

Electroencephalographic analysis of activities in the optic tectum of unrestrained carp

Electroencephalographic activity of the optic tectum in unrestrained resting carp was classified into three dominant frequency ranges of 4–7, 8–13 and 14–25 Hz, peaking at 6, 10, and 17 and 22 Hz, respectively, under power spectral analysis. All these activities were suppressed in the dark. The suppression was most prominent in the 8–13 Hz waves, but less so in the 4–7 Hz. However, while the fish was swimming actively, the 4–7 Hz spectrum increased in power and no actual increase could be observed for the higher frequency waves. Thus, it is probable that the 4–7 Hz waves involve rich motor activity, while the 8–13 Hz waves are mainly visual. The tectal activity was enhanced in the hypoxic state, with an increase in all frequency components, and enhanced further after loading, each of which corresponds to the hypoxic and post-hypoxic activations described for the mammalian cortex.A component analysis for the photically evoked response in restrained carp supported the four peaks of fundamental tectal rhythm being obtained as the spontaneous activity. In addition, each component belonging to the lower two peaks could be decomposed into the others, suggesting that the 17 and 22 Hz waves might be elementary for the tectal activity.     

Usefulness of polyethylene glycol solution with dimethylpolysiloxanes for bowel preparation before capsule endoscopy

Background and Aim:  Capsule endoscopy (CE) is widely used for diagnosing small intestinal diseases. In some cases, however, observation of target sites is very poor during CE because of residues etc. Herein we report the usefulness of a preparation comprised of polyethylene glycol solution (PEG) for CE.
Methods:  This was a prospective, randomized, and single-blind study. Forty subjects, fasted for 12 h before CE, were randomized into two groups: 20 subjects in Group A were fasted only, whereas 20 in Group B received 1 liter (L) PEG with 200 mg dimethylpolysiloxane 3 h before CE. For evaluation, the observation period of the small intestine was divided into first and second halves. Subsequently, four investigators, blinded as to which group received the preparation, assessed the condition of the intestine using four rating scales in terms of 'residue' and 'intraluminal gas bubbles'. The effects of the preparation were statistically compared.
Results:  CE images were better in Group B than in Group A with respect to 'intraluminal gas bubbles' ( P  = 0.0038) in the first half of the observation period, as well as residue ( P  = 0.0087) and intraluminal gas bubbles ( P  = 0.0011) in the second half.
Conclusion:  Bowel preparation using 1 L PEG with dimethylpolysiloxane 3 h before CE significantly reduced residue and intraluminal gas bubbles, and was considered to be a useful method for CE.     

Reversible cortical auditory dysfunction caused by cerebral vasospasm after ruptured aneurysmal subarachnoid hemorrhage and evaluated by perfusion magnetic resonance imaging. Case report

A 52-year-old woman developed subarachnoid hemorrhage (SAH) caused by a ruptured right internal carotid artery (ICA) aneurysm. Because of the aneurysm configuration, the authors decided to delay surgery and instead undertook serial imaging studies of the aneurysm. The patient remained alert but developed acute bilateral deafness on Day 7. Audiological examination and auditory brainstem responses suggested that the hearing disturbance was cortical in origin. Three-dimensional computed tomography (CT) angiography showed severe vasospasm in the right middle cerebral artery (MCA) and moderate vasospasm in the left ICA and MCA. Three-tesla magnetic resonance (MR) imaging was performed 2 days after the onset of symptoms. Diffusion-weighted and T2-weighted MR images showed an acute infarction in the right insular cortex caused by vasospasm. Perfusion-weighted MR imaging, particularly mean transit time mapping, revealed hypoperfusion in both temporal lobes including the auditory cortex and right auditory radiation. The vasospasm was treated with induction of mild hypertension and hypervolemia. Follow-up MR images, 3D CT angiograms, and audiometry performed 2 weeks after the first examination showed recovery of vasospasm and resolution of perfusion abnormality and hearing disturbance. On Day 26, the aneurysm was successfully occluded with clips and the patient was discharged with no deficits. To the authors' knowledge, this is the first reported case of reversible cortical auditory dysfunction purely due to bilateral cerebral vasospasm detected using perfusion MR imaging after SAH.     

Combined effects of meropenem and aminoglycosides on Pseudomonas aeruginosa in vitro

To investigate combinations of antibiotics against Pseudomonas aeruginosa, the in vitro effects of combinations of meropenem with each of three aminoglycosides, arbekacin, amikacin and netilmicin, were evaluated using an agar dilution chequerboard technique. The combinations of meropenem and aminoglycosides were effective against almost all P. aeruginosa strains tested, which included meropenem-resistant strains. Increased synergic effects were observed in combinations that included arbekacin or amikacin. None of the combinations had an antagonistic effect. Most of the synergic and additive effects were achieved at clinically relevant concentrations.