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Biomedical subjects

H Seto

Publications and source records attributed to H Seto.

At least 433 records · Page 24Linked to original sources
PubMed1974

Early stages in DNA binding and uptake during genetic transformation of pneumococci.

Ethylenediaminetetraacetate and other divalent-cation-complexing agents greatly stimulate the cellular binding of DNA molecules to competent pneumococci, while the appearance of genetic transformants and nuclease-resistant DNA binding are completely inhibited. Based on this finding, we developed an experimental system in which three early and consecutive stages of genetic transformation can be experimentally separated: (i) attachment of DNA molecules to cell surface sites that are only demonstrable in the competent state; (ii) a divalent-cation-dependent nucleolytic splitting and release of the adsorbed molecules to the medium; and (iii) emergence of potential transformants accompanied by an energy-requiring and divalent-cation-dependent process in which the cell-associated DNA molecules become inaccessible to shearing forces, nucleases, anti-DNA serum, and polycations.

Binding Sites↗
PubMed1969

Inducible synthesis of beta-galactosidase in disrupted spheroplast of Escherichia coli.

A membrane preparation obtained from osmotic lysate of spheroplasts of Escherichia coli cells showed an activity of synthesizing beta-galactosidase which was dependent upon oxidative phosphorylation. The synthesis was inhibited by the addition of actinomycin D or of chloramphenicol. The beta-galactosidase synthesized in the membrane preparation was completely released into the medium, while that synthesized in the spheroplasts and intact cells remained within the cells. The minimum concentration of the inducer, methyl-beta-d-thiogalactoside, required for the induction of beta-galactosidase was 5 x 10(-5)m for intact cells, 3 x 10(-4)m for spheroplasts and 1 x 10(-3)m for membrane preparation. Incorporation of labeled glucose into insoluble components in membrane preparation was extremely low compared with that in intact cells or in spheroplasts. Based on these and other observations, the nature of this membrane preparation is discussed in relation to the structure of E. coli cells.

Bacteriolysis↗
PubMedDate not supplied

Thoracic esophageal carcinoma: evaluation in the sagittal section with magnetic resonance imaging.

Among 54 patients with thoracic esophageal carcinoma (53 squamous cell carcinoma, 1 adenosquamous carcinoma), the usefulness of MR sagittal imaging for evaluating local extent (T factor) was examined by measuring the anteroposterior (AP) diameter of the tumor. The MR examination was performed using ECG gated scans with a 3 mm slice at 1.5 Tesla. T1-weighted sagittal images were obtained. In 10 patients the appearance of the esophagus was normal, and in 44 patients a tumor was detected in the sagittal section. Thirty-seven lesions were histologically proved (Tis, 1; T1, 3; T2, 3; T3, 15; T4, 15). Lesions classified as 30 mm were resected. They were located in the lower esophagus. It is concluded that lesions detected in MR sagittal images might be T3 or T4 tumors, and masses of >30 mm might extend to adjacent organs, although two tumors with an AP diameter < 25 mm also invaded the trachea.

Adult↗
PubMedDate not supplied

Clinical utility of three-dimensional time-of-flight magnetic resonance angiography for the evaluation of intracranial aneurysms.

Magnetic resonance (MR) angiographic studies of 14 patients with intracranial aneurysms (AN) were analyzed retrospectively as compared with contrast angiographic studies. Eighteen of 19 (95%) lesions were detected, and the relation between AN and their parent vessels was precisely assessed. The diameter of the smallest aneurysm detected in our case was 3 mm. However, small vessels around AN were not visualized. Therefore, MR angiography (MRA) is definitely not a substitute for preoperative contrast angiography. MRA is a useful screening tool for nonruptured AN, but further refinement is required to evaluate emergency ruptured AN.

Adolescent↗
PubMedDate not supplied

A case of retroperitoneal extramedullary plasmacytoma with multiple metastases.

We investigated a patient with extramedullary plasmacytoma in the retroperitoneal space with multiple metastases using abdominal CT scan and 67Ga scintigraphy. Abdominal enhanced CT revealed the retroperitoneal tumor mimicking lymphoma. 67Ga scintigraphy showed multiple tumor localization. We could detect retroperitoneal extramedullary plasmacytoma with multiple metastases using 67Ga scintigraphy. This retroperitoneal tumor may appear similar to lymphoma on CT.

Diagnosis, Differential↗
PubMedDate not supplied

Qualitative evaluation of chronic diffuse liver disease by STIR MRI.

OBJECTIVE: The purpose of our study was to characterize the relationship between signal intensity on STIR MRI, histology, and liver function. MATERIALS AND METHODS: MRI was performed in 39 patients with chronic liver diseases [chronic persistent hepatitis (CPH), chronic active hepatitis (CAH), liver cirrhosis (LC)] and 11 patients without liver dysfunction (normal). RESULTS: On STIR images, very low signal intensities compared with those of the spleen were seen in all 11 normal livers (100%), and brighter intensities were seen in chronic diffuse liver diseases (10 patients with CPH, 11 patients with CAH, and 18 patients with LC) (100%). The higher the signal grade on STIR images (moderate, marked), the more advanced was the chronic diffuse liver disease (p < 0.02). The levels of serum glutamic-oxaloacetic and glutamic-pyruvic transaminase increased in parallel with increasing signal intensity on STIR images (both p < 0.01). CONCLUSION: We found that the signal intensity of liver on STIR images appeared to be associated with the degree of histologic and/or clinical severity in patients with chronic liver disease.

Adult↗
PubMedDate not supplied

MR sialographic evaluation of sialectasia of Stensen's duct: comparison with X-ray sialography and ultrasonography.

We describe a patient with unilateral sialectasia of Stensen's duct. X-ray sialography, MR sialography, and ultrasonography showed multiple stenoses and rosary dilatation of Stensen's duct during stimulation of the parotid gland. Before stimulation, Stensen's duct showed focal dilatation as indicated by MR sialography and ultrasonography. The patient also had ipsilateral masseter hypertrophy (BMH), which may be a cause of sialectasia.

Adult↗