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Biomedical subjects

J C Hwang

Publications and source records attributed to J C Hwang.

At least 91 records · Page 5Linked to original sources
PubMed1975

An electrophysiological study of the sacculo-ocular pathways in cats.

Microelectrode recordings of neuronal activities in the cat were made in the vestibular main nuclei and the y group cells in response to stimulation of the saccule and IIIrd (oculomotor) nuclei. A relatively new anaesthetic (Ketalar, Parke Davis Co.) that apparently did not suppress transmissions through the sacculo-oculomotor pathways was used. A social accessory arm to replace one side of the standard stereotaxic frame was designed to permit surgical access to the inner ear. Orthodromic focal potentials indicating monosynaptic activation were recorded in the region of the lateral and inferior vestibular nuclei in response to ipsilateral stimulation of saccule. Antidromic field potentials in response to IIIrd nuclear stimulation were also recorded. Similar results were obtained from the y group cells. Unit recordings demonstrated that neurones in the rostral part of the lateral vestibular nucleus received monosynaptic excitation from the saccule before projecting to the IIIrd nuclei. However, studies on the y group cells indicated the existence of a separate and distinct pathway in the sacculo-oculomotor reflex. This pathway involves at least three synapses before reaching the motoneurones.

Animals↗
PubMedDate not supplied

Colonic wall thickening in cirrhotic patients: CT features and its clinical significance.

BACKGROUND: To evaluate the computed tomographic (CT) features of colonic wall thickening in cirrhotic patients and to determine their prognostic value. METHODS: We retrospectively reviewed 28 cirrhotic patients with colonic wall thickening (>/=10 mm) on CT. Twenty-six of the 28 patients had hepatocellular carcinoma. The severity of hepatic dysfunction was determined by using the Child-Pugh classification. We analyzed the patterns of bowel wall thickening and degree of portal hypertension on CT and the survival periods after initial CT detection of colonic wall thickening. RESULTS: The involved segment of the colon was diffusely thickened with either scalloped or nodular circumferential configuration. In all patients, the thickened colonic wall enhanced poorly. Although the ascending colon was involved in all patients, the transverse (n = 14) or descending (n = 5) colon was also simultaneously involved. Most patients exhibited an advanced stage of portal hypertension on CT. The median survival period of 25 patients who expired was 34 days, and 21 patients (84%) expired within 3 months. CONCLUSIONS: Colonic wall thickening on CT can be used as one of the indicators of poor prognosis in cirrhotic patients. Advanced liver cirrhosis with significantly severe dysfunction is the likely cause of mortality. Therefore, a less aggressive therapeutic approach is recommended if hepatocellular carcinoma is coexistent in these patients.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Pleural and pulmonary staining at inferior phrenic arteriography mimicking a tumor staining of hepatocellular carcinoma.

PURPOSE: To describe the findings of pleural and pulmonary staining of the inferior phrenic artery, which can be confused with tumor staining during transarterial chemoembolization (TACE) of hepatoma. METHODS: Fifteen patients who showed pleural and pulmonary staining without relationship to hepatic masses at inferior phrenic arteriography were enrolled. The staining was noted at initial TACE (n = 8), at successive TACE (n = 5), and after hepatic surgery (n = 2). The angiographic pattern, the presence of pleural change on computed tomography (CT), and clinical history were evaluated. RESULTS: Draining pulmonary veins were seen in all cases. The lower margin of the staining corresponded to the lower margin of the pleura in 10 patients. CT showed pleural and/or pulmonary abnormalities in all cases. After embolization of the inferior phrenic artery, the accumulation of iodized oil in the lung was noted. CONCLUSION: Understanding the CT and angiographic findings of pleural and pulmonary staining during TACE may help differentiate benign staining from tumor staining.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Microcomputer-based spike train analysis.

A system has been developed to analyse statistically the information contained within neuronal spike trains in the central nervous system. The system consists of a microprocessor development system, together with the peripheral components and transducers. Suitable software packages have been developed to analyse statistical parameters including the mean, variance, entropy, conditional entropy, serial correlation coefficients, Markov dependency and Markov order. By linking up the required routines, the system is capable of responding in real-time and plotting the desired results from the spike train obtained. Such system has been used to study the neuronal spike trains recorded from central vestibular neurons which could be affected by positional changes, anaesthetics and various drugs for the relief of motion sickness.

Animals↗
PubMedDate not supplied

Crossed sacculo-ocular pathway via the Deiters' nucleus in cats.

Single unit recordings were made in the Deiters' nucleus of cats in response to electrical stimulation of the superior area of the contralateral saccule and the ipsilateral oculomotor (IIIrd) nuclear complex. Correct placements of the stimulating and recording electrodes were identified by upward movements of the eyeballs associated with characteristic field potentials in the Deiters' nucleus. Stimulation of the contralateral saccule induced a negative N wave followed by positive P1 and P2 potentials. One hundred twenty-two units responded to contralateral saccular stimulation with a mean latency of 2.48 +/- 0.06 msec (SEM). Of these, only the responses of 31 cells could be made to collide with antidromic spikes evoked from ipsilateral IIIrd nuclear stimulation. This implies that the crossed sacculo-ocular pathway would involve at least four neurons with one commissural cell interposing between the bilateral vestibular nuclei.

Afferent Pathways↗