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Biomedical subjects

J Kim

Publications and source records attributed to J Kim.

At least 1,171 records · Page 65Linked to original sources
PubMed1985

Activation of dorsal horn cells by ventral root stimulation in the cat.

Responses of dorsal horn cells to ventral root stimulation were determined for the L7 and S1 levels of the spinal cord of 14 anesthetized cats. Forty-six dorsal horn cells were found that were excited by stimulation of the distal stump of the cut ventral root. For maximum excitation it was necessary to use a train of stimuli. For the 34 dorsal horn cells whose peripheral receptive-field properties could be characterized, 14 were wide dynamic range cells and 19 were high-threshold cells. The other cell responded exclusively to stimulation of deep tissue. None of the cells responded exclusively to innocuous stimuli, and all responded more vigorously to noxious than to innocuous stimuli. Some cells also responded to noxious heat applied to the skin of the receptive field. Locations of 10 of the activated dorsal horn cells were identified. They were distributed throughout the dorsal horn, but most were found in laminae V and VI. In four animals, both the proximal and distal stumps of the cut S1 ventral root were stimulated while searching for dorsal horn cells. Ten dorsal horn cells were found that were excited by stimulation of the distal stump of the ventral root. No cells were found that responded to proximal stump stimulation. To prevent current spread by stimulation of the ventral root, an extra ground electrode was placed distal to the stimulating electrodes. When the ground electrode was removed, distinctive signs of current spread appeared in that a cord dorsum potential could be recorded and the dorsal horn neuronal responses changed. Dorsal horn neurons could also be excited by nonelectrical stimuli such as crushing the ventral root. If the ventral root was crushed distal to the stimulating electrodes, however, the initially excited cell could no longer be activated by ventral root stimulation. Activation of dorsal horn cells by stimulation of the distal stump of a cut ventral root was abolished when the dorsal root of the same segment was sectioned. Conduction velocities of the fibers in the ventral root that excited dorsal horn cells ranged between 0.25 and 1.78 m/s with a mean of 0.91 +/- 0.47 (SD) m/s. These results show that there are unmyelinated afferent fibers in the ventral root that enter the spinal cord through the dorsal root and excite dorsal horn cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Bupropion in the long-term treatment of cyclic mood disorders: mood stabilizing effects.

The effects of bupropion HCl in treating 11 patients with bipolar or schizoaffective disorder were examined in an open trial. Most patients had been intolerant of or showed minimal to moderate improvement on lithium, neuroleptics, antidepressants, or a combination of these drugs. All patients were maintained on bupropion alone or bupropion in combination with low-dose neuroleptics or anxiolytics for 1 year or more, with little or no relapse and few side effects.

Adult↗
PubMed1984

Segmental distribution of dorsal root ganglion cells with axons in the inferior cardiac nerve.

The segmental distribution of visceral afferent neurons with axons in the cardiac nerve was studied in cats with the horseradish peroxidase (HRP) technique. After HRP was introduced into the left inferior cardiac nerve, labeled dorsal root ganglion cells were found in the ganglia from the C7 to T7 spinal levels, with a wide variation in distribution among the individual animals. An average of 93 cells was labeled per animal. The data indicate that the afferent nerve fibers in the inferior cardiac nerve project to a much wider range of segments of the spinal cord than previously believed.

Animals↗
PubMed1984

Polyacrylamide-gel electrophoresis and Alcian Blue staining of sulphated glycosaminoglycan oligosaccharides.

Oligosaccharide fragments of glycosaminoglycans may be separated for rapid analysis by electrophoresis through a 10% polyacrylamide matrix. An extensive ladder-like set of bands is observed for partial testicular hyaluronidase digests of chondroitin 4- or 6-sulphate, and for dermatan sulphate. Co-electrophoresis of purified oligosaccharides has established that the major bands of these patterns represent fragments differing in chain length by one disaccharide unit, with the smallest fragments having the greatest mobility. Additional minor bands, representing heterogeneity in the repeating unit structure, are also observed. There are slight differences in the mobilities of oligosaccharides derived from the three major types of sulphated glycosaminoglycans. Alcian Blue is employed for visualization of the digest fragments. Sample loads of 5-10 micrograms per band appear optimum. The smallest oligosaccharide which may be stained by this method is the hexasaccharide. After consideration of this effect, a good correlation is found to exist between densitometric scans of the gel-electrophoretic patterns and gel-filtration chromatographic profiles based on uronic acid concentration.

Alcian Blue↗
PubMed1984

Prolactin-secreting pituitary adenomas: CT appearance in diffuse invasion.

The authors describe 2 diffusely invasive prolactin-secreting pituitary adenomas which produced marked destruction of the base of the skull thought to be diagnostic of chordoma on computed tomography (CT). Failure to recognize this pattern led to biopsy, which was diagnostic. The authors emphasize the need to recognize this rare growth pattern of diffusely invasive pituitary adenoma on CT.

Adenoma↗
PubMed1984

Effects of deoxycoformycin in mice. II. Differences between the drug sensitivities and purine metabolizing enzymes of transplantable lymphomas of varying immunologic phenotypes.

Transplantable BALB/c and AKR lymphomas of different cell surface immunologic phenotypes have distinctive patterns of response to the ADA inhibitor DCF in vivo and in vitro. BAL 9, a lymphoma of the Lyt-1+,2+ T cell phenotype, was the most sensitive to DCF in vivo, and its DNA synthesis was inhibited more than 95% when cultured in the presence of dAr and DCF in vitro. This was correlated with a 10-fold increase in dATP content. The ADA and AMPDA activities were both high. Two lymphomas of the Lyt-1-,2+ T cell phenotype, BAL 5 and AKTB - lt , as well as two B cell phenotype lymphomas, A20 .3 and AKTB -lb, were all moderately inhibited in their in vivo growth if enough DCF was administered. However, their DNA synthesis in vitro was only inhibited 8 to 24% by dAr and DCF, there was only a twofold increase in the accumulation of dATP, and ADA and AMPDA activities were both low in the two BALB/c lymphomas tested. BAL 13, the only lymphoma of the Lyt-1+,2- phenotype examined, was completely resistant to DCF in vivo and in vitro. When cultured in the presence of dAr and DCF there was a transient increase in dATP content, followed by an abrupt decline. AMPDA activity was five to seven times greater than in the other lymphomas tested. ADA activity was moderate. The activities of 5' nucleotidase and of adenosine kinase were low and approximately equal in all the BALB/c lymphomas. These results suggest that the response to DCF by lymphomas of various immunologic phenotypes can be correlated with their nucleoside metabolism. The sensitivity of BAL 9 and the resistance of BAL 13 to DCF are correlated with their tendency to accumulate dATP and with their AMPDA and ADA activity ratios. The moderate sensitivity to DCF in vivo of the other T and B cell lymphomas, however, could not be clearly explained by any of the in vitro parameters thus far investigated, and this suggests that mechanisms inhibiting lymphoma proliferation other than dATP accumulation may be operating.

Adenosine Deaminase↗
PubMed1983

Crystallographic data for complexes of the Cro repressor with DNA.

Complexes of the bacteriophage lambda Cro repressor with two DNA duplexes have been crystallized. The DNA sequences are equimolar mixtures of ApTpCpApCpC and its complementary strand and ApCpCpGpCpApApGpG and its complementary strand, which are both parts of the lambda OR3 operator. The space group of both co-crystals is C2221 with cell dimensions a = 81.1 A, b = 89.2 A, and c = 80.0 A. Analysis of dissolved crystals shows that they respectively contain approximately two hexamers per Cro dimer and one nonamer per dimer. The co-crystals diffract to about 3 A resolution and appear suitable for structural studies.

DNA↗
PubMed1983

Asymmetric distribution and temperature-dependent clustering of filipin-sterol complexes in the nuclear membrane of Ehrlich ascites tumor cells.

When Ehrlich ascites tumor (EAT) cells were fixed at 4 degrees C and freeze-fractured, patchy areas having no intramembrane particles were visible in the nuclear envelope. The particle free areas (PFAs) were not seen on fixation at 28 degrees C, indicating that appearance of PFAs was caused by a kind of thermotropic phase separation. The PFAs were detected only in the nuclear membrane, and not in the plasma membrane. Most of them were present in the outer membrane of the nuclear envelope. In cells fixed at 4 degrees C, and treated with filipin all the filipin-sterol complexes appeared in clusters located in the PFAs. In contrast, the filipin-sterol complexes were evenly distributed in cells fixed at 28 degrees C. This suggests that at low temperature, molecules of cholesterol gather in the PFAs. Temperature-dependent cluster formation was seen only in the complexes of the nuclear membrane, suggesting that the cholesterol in the nuclear membrane is more mobile than that in the plasma membrane. In addition, the distribution of filipin-sterol complexes in the nuclear envelope was asymmetric. The complexes were seen only in the outer (cytoplasmic), but not in the inner (nucleoplasmic) membrane of the nuclear envelope, reflecting differences in the structural, and presumably functional, characteristics of the outer and inner nuclear membranes.

Animals↗
PubMed1983

Intracranial tuberculomas in a child: computed tomographic scan diagnosis and nonsurgical management.

Despite great strides in screening and detection of tuberculosis, urban areas still harbor many children with this disease. The case of a child with probable intracranial tuberculomas who was medically treated with antituberculous therapy and followed with frequent computed tomographic (CT) scans is reported. Despite older textbooks that espouse surgery as the treatment for intracranial tuberculomas, it is suggested that in the era of CT scanning, they should be treated the same as other focal CNS infections. Surgery should be reserved for medical failure or deteriorating conditions.

Antibiotics, Antitubercular↗
PubMed1982

Glycoproteins of Sendai virus (HVJ) have a critical ratio for fusion between virus envelopes and cell membranes.

The biological activity of two glycoproteins, hemagglutinin and neuraminidase (HN) and fusion (F) proteins, of Sendai virus (HVJ) were studied using purified proteins. The proteins were purified by chromatography on DEAE and CM cellulose in the presence of Nonidet P-40 (NP40). The glycoproteins were reconstituted at various ratios of F to HN into lipid vesicles containing fragment A of diphtheria toxin. The association of HN and F proteins with the vesicles was confirmed by electron microscopy and sucrose density gradient centrifugation. The cytotoxic activity of vesicles containing fragment A on fusion with L cells was determined by measuring colony formation of the cells. It was found that for maximum cytotoxic activity of the vesicles, there was an optimal ratio of F to HN of two. This suggests that HN is not merely the initial binding site to the cell surface, and that interactions between HN and F proteins on the virus surface may be important for the biological activities of these proteins on the cells.

Animals↗