Past rifampicin dosing determines rifabutin resistance of Helicobacter pylori

BACKGROUND

Recently, the number of Helicobacter pylori isolates showing antibiotic resistance has been increasing. Rifabutin (RFB) is one of the possible candidates for H. pylori eradication. In the present study, the RFB minimum inhibitory concentrations (MICs) and the resistance-determining genes to RFB (rpoB) were examined to clarify the relationship between drug MICs, rpoB mutations, and past history of rifampicin (RFP) treatment.

METHODS

The MICs of RFB and rpoB mutations were examined for 48 strains with failure of H. pylori eradication in the University Hospital and 46 isolated from patients at a specialized hospital for chronic respiratory diseases without past H. pylori eradication. Past RFP treatment was also examined.

RESULTS

Eight of 94 strains showed high RFB MICs and 6 of the 8 strains showed rpoB point mutations. Although no strains showed high RFB MICs among 48 strains from the patients in the University Hospital, all 7 strains isolated from patients with past RFP treatment showed high RFB MICs (>or=0.12 mg/l).

CONCLUSION

Although RFB might be a potential candidate component of a new H. pylori eradication regimen following the first- or second-line failure, it should be used after examining a past history of RFP treatment.

[Evaluation of patients with cerebral infarction using transesophageal echocardiography: atherosclerotic changes in the thoracic aorta and the branches of the aortic arch]

Atherosclerotic disease of the aortic arch is thought to be a potential source of cerebral emboli, but this disease in the branch of the aortic arch has not been extensively explored. This study assessed atherosclerotic lesions in the thoracic aorta and the branches of the aortic arch using transesophageal echocardiography in patients with cerebral infarction, and simultaneously searched for potential cardiac sources for emboli. Thrombi were detected in the left atrial appendage in nine of 54 patients with cerebral infarction and these patients were excluded. The remaining 45 patients with cerebral infarction (31 males and 14 females aged 68.5 +/- 7.4 years) and 35 normal subjects (21 males and 14 females aged 69.2 +/- 9.5 years) were evaluated. The thickness of the wall was measured in the branches of the aortic arch (brachiocephalic trunk, left common carotid artery and left subclavian artery) as well as the thoracic aorta (ascending aorta, aortic arch and descending aorta). Atherosclerotic lesions were defined as increased echogenicity of the intima (intimal thickening), calcification, protruded plaque, ulceration or plaque with cystic lesion. The thicknesses of the wall in the aortic arch (3.84 +/- 1.25 vs 2.71 +/- 1.33 mm, p < 0.01), left common carotid artery (2.67 +/- 1.10 vs 2.16 +/- 0.91 mm, p < 0.05) and the left subclavian artery (2.52 +/- 0.67 vs 2.15 +/- 0.88 mm, p < 0.05) were significantly greater in patients than in the normal subjects. The incidence of plaque or ulceration was significantly increased in patients with cerebral infarction compared with the normal subjects in the aortic arch (76% vs 43%, p < 0.05) and left common carotid artery (44% vs 17%, p < 0.05). Transesophageal echocardiography can detect possible sources of emboli in the branches of the aortic arch as well as the thoracic arch in patients with cerebral infarction.

Evidence for an antemortem injury of a burned head dissected from a burned body

A 41-year-old woman was killed following blows to the head with a bat. Her body was burned and her head was dissected with a saw and hidden in the soil. Although the body was discovered within a few days of her death, the putrescent head was not located until four months later. A fracture of the left temporal bone was found in the head, which was partially charred. The confession of the murder suspect was unreliable, and the police suggested that the cause of death may not have been a head injury but asphyxia, and that the bone fracture to the head may have been caused after its dissection. It was therefore necessary to determine when the fracture was formed. The fracture line continued to the base of the skull, indicating that it was not due to heat. Magnetic resonance computed tomography (MR-CT) indicated the existence of a blood clot in the left mastoid cells, across which the fracture line passed. Upon sectioning of the skull with a saw, a dark red clot was located in the left mastoid cells, indicating that bleeding had occurred before the body was set alight. It seemed most logical to assume that the bone fracture was formed when the victim was alive, or before her body was burned.

Convergence of afferents from the SLN and GPN in cat medullary swallowing neurons

We demonstrated the convergence of information from the pharyngeal and laryngeal mucosa, transmitted by the glossopharyngeal nerve (GPN) and superior laryngeal nerve (SLN), in the nucleus of the tractus solitarius (NTS). First, the distribution of terminals of the GPN and SLN in the NTS was examined by an HPR tracing technique in cats, and the synapse formation of these neurons with NTS neurons was demonstrated by electron microscopy. The HRP-labeled SLN and GPN terminals were localized in a small area of the interstitial subnucleus of the NTS, slightly rostral to the obex, forming synapses with NTS neurons. Next, using extracellular recording in anesthetized cats, we determined whether or not swallowing-related neurons in the medulla oblongata receive peripheral inputs. Convergence of peripheral sensory inputs from the SLN and GPN was observed in more than 80% of the NTS cells. These results suggest that the NTS is not only a sensory-relay nucleus but also integrates information necessary for eliciting protective reflexes of the upper airway, such as swallowing.