Biomedical subjects

J Hahm

Publications and source records attributed to J Hahm.

5 recordsLinked to original sources

PubMed2000

Structural and topological differences between a glycopeptide-intermediate clinical strain and glycopeptide-susceptible strains of Staphylococcus aureus revealed by atomic force microscopy.

Novel cell surface topography was revealed on cocci from a glycopeptide-intermediate Staphylococcus aureus (GISA) clinical strain by using atomic force microscopy. The GISA isolate and its revertant had two parallel circumferential surface rings. One equatorial surface ring was observed in control strains. In vancomycin-susceptible strains, additional rings were formed in the presence of vancomycin. Ring depth measurements also revealed striking differences between the GISA strain and susceptible strains grown with or without vancomycin.

Anti-Bacterial Agents↗

PubMed2000

Changes in gallbladder motility in gastrectomized patients.

OBJECTIVES: Gastric resection may predispose gallstone formation. However, the mechanism has not been clearly understood. To evaluate the relationship between gastric resection and gallstone formation, we compared gallbladder(GB) motility in gastrectomized patients and control subjects. METHODS: We compared the GB volume and ejection fraction of the 46 gastrectomized patients with 37 healthy controls using real time ultrasonography. RESULTS: GB volume increased significantly in the gastrectomized group in fasting (30.2 +/- 13.9 ml). The GB volume after a fatty meal was greater in the gastrectomized group (12.6 +/- 6.4 ml) than in the control group (4.3 +/- 3.3 ml) (p < 0.01). A significant reduction of ejection fraction was found in gastrectomized patients (56.9 +/- 13.0%) in comparison with the control group (75.5 +/- 16.1%) (p < 0.01). The GB ejection fraction had a poor correlation to the postoperative period (r = 0.232). CONCLUSION: A gastrectomy appears to be a risk factor of GB dysmotility, which may play a major role in gallstone formation in gastrectomized patients.

Adult↗

PubMed1995

The role of contrast enhanced computed tomography in the diagnosis of low density pulmonary nodules.

Contrast enhanced CT manifestations of 141 pulmonary nodules having internal density less than 40 HU were evaluated to study the prevalence of causative disease and their differential points. Tuberculosis (n = 79) was most common, active in 96%. There were 22 cancers, 10 abscesses, 9 paragonimiases, 8 cysts, 7 metastases, 4 aspergillomas without air meniscus sign, and so on. 35% of the benign lesions were greater than 3 cm in diameter and 67% of benign lesions did not show a smooth outer margin. Lung cysts and aspergillomas showed relatively thin peripheral enhanced rim (PER), sharp transitional zone (TZ), a smooth inner border (IB), and homogeneous low densities (LD). Tuberculous nodules tended to be smaller in size with thin PER and most had smooth IB and homogeneous LD. Paragonimiasis, abscess, and cancer tended to present with thick PER and lobulated IB. Lung abscess and paragonimiasis both showed homogeneous LD and narrow TZ. However, in paragonimiasis, multiple locules were seen. Lung cancer showed wider TZ and heterogeneous LD. The size and outer margin of pulmonary nodules as a diagnostic criteria is less useful in LD pulmonary nodule. Therefore, CT can be more useful in differentiating the benign from the malignant lesions by observing a more specific and characteristic pattern of peripheral enhanced rim, transitional zone, inner border, and homogeneity of low density area.

Adolescent↗

PubMed1994

Morphology of retinal axons induced to arborize in a novel target, the medial geniculate nucleus. I. Comparison with arbors in normal targets.

Ferret retinal axons can be induced to innervate the medial geniculate nucleus (MGN) by a combination of brain lesions early in development. Our previous work suggests that the retinal ganglion cells responsible for this plasticity are W cells. The present study continues this work with a morphological investigation of normal retinal ganglion-cell axons and retinal ganglion-cell axons induced to arborize in the MGN. Retinal axons were bulk filled with horseradish peroxidase placed in the optic tract, and individual axons were serially reconstructed from sagittal sections. The control population consisted of fine-caliber axons arborizing in the superior colliculus (SC) and in the ventral C laminae of the lateral geniculate nucleus (LGN) of normal ferrets. We also compared the axons in the MGN of lesioned ferrets to intracellularly filled X and Y axons from normal ferrets as reported by Roe et al. ([1989] J. Comp. Neurol. 288:208). We have found that the retino-MGN axons in the lesioned ferrets do not resemble X or Y axons in normal ferrets in axon diameter, arbor volume, bouton number, or bouton density. However, they do resemble the fine-caliber, presumed W axons arborizing in the C laminae of the LGN and in the SC of normal ferrets. Thus, this study, in combination with previous studies, suggests strongly that W retinal ganglion cells are responsible for the retinal input to the MGN in lesioned animals. In addition, we find that the retino-MGN axons are of two types, branched and unbranched, which may correspond to different subtypes of retinal W cells.

Animals↗

PubMed1994

An N-methyl-D-aspartate receptor antagonist does not prevent eye-specific segregation in the ferret retinogeniculate pathway.

Recent studies have shown that electrical activity, particularly that mediated by NMDA receptors, has a profound effect on the development of specific neuronal connections. Blocking NMDA receptors in the ferret's lateral geniculate nucleus prevents the segregation of retinal afferents into ON and OFF sublaminae. We have now examined the involvement of NMDA receptors in the separation of afferents from the two eyes that occurs in the lateral geniculate nucleus several weeks earlier in development. Blockade of NMDA receptor activity does not appear to interfere with this eye-specific segregation.

Animals↗