Biomedical subjects

M Kim

Publications and source records attributed to M Kim.

At least 19 recordsLinked to original sources

PubMed1992

Effects of intra-amygdala injections of NMDA receptor antagonists on acquisition and retention of inhibitory avoidance.

These experiments examined the effects of intra-amygdala injections of NMDA receptor antagonists on the acquisition and retention of inhibitory avoidance. In Expt. I, rats received bilateral intra-amygdala injections of the NMDA antagonists D,L-AP5 (1-10 micrograms), D-AP5 (0.03-1 micrograms), CPP (0.125 or 0.375 microgram), or MK-801 (0.2 or 0.5 microgram) prior to training in a continuous multiple-trial inhibitory avoidance (CMIA) task. Acquisition of the task was not significantly affected by any of the drug injections. In contrast, all three competitive antagonists, D,L-AP5, D-AP5 and CPP, produced dose-dependent impairment of 48 h retention performance. Although the MK-801 injections did not significantly impair retention performance, the retention scores of the 0.5 microgram MK-801 group were bimodally distributed, indicating retention impairment in a subgroup of the animals given that dose. Intra-amygdala injections of 3 or 10 micrograms D,L-AP5 did not affect footshock sensitivity (Expt. II) or locomotor activity (Expt. III) and their retention-impairing effects were not due to induction of state dependency (Expt. IV). The retention-impairing effects of intra-amygdala injections of NMDA antagonists were not due to diffusion of the drugs dorsally: injections of 1 microgram D-AP5 into the striatal area directly above the amygdala impaired acquisition but not retention performance (Expt. V). The retention-impairing effects of 1 microgram D-AP5 or 0.5 microgram MK-801 were attenuated by giving additional training to the animals shortly after receiving intra-amygdala injections (Expt. VI). The implications of these findings for hypotheses concerning amygdala function in learning and memory are discussed.

Amygdala↗

PubMed1992

Hepatitis B virus and apparent fulminant non-A, non-B hepatitis.

While there is evidence that hepatitis C virus (HCV) does not cause fulminant non-A, non-B hepatitis, the causal agent remains unknown. To evaluate the role of hepatitis B virus (HBV) in this disease, we used a two-step polymerase chain reaction (PCR) to amplify the surface and core regions of HBV DNA in serum and liver samples taken prospectively from twenty-six patients (mean age 36 years, range 1 to 64) with acute hepatic failure undergoing liver transplantation. HBV DNA was absent from the serum of all patients before transplantation. Seventeen patients were diagnosed as having non-A, non-B hepatitis because they lacked serological evidence of hepatitis A virus or HBV infection. Liver samples were taken from twelve of these patients, and six samples were positive for HBV DNA. By contrast HBV DNA was not detected in liver from three patients with acute liver failure caused by hepatitis A or toxins. HCV RNA was not found in pretransplant samples by PCR. Four of the six patients with detectable HBV DNA in liver and presumptive non-A, non-B hepatitis had detectable HBV DNA in serum after transplantation. One additional patient who did not donate pretransplant liver had HBV DNA in a post-transplant serum sample. Thus, HBV DNA was present before or after transplantation in seven of seventeen patients with apparent non-A, non-B hepatitis. Three of five patients with detectable post-transplant serum HBV DNA were serologically positive for HBV surface antigen. These findings indicate that HBV may be a common cause of fulminant hepatic failure in patients lacking serological evidence of HBV infection.

Acute Disease↗

PubMed1992

Regulation of purine nucleotide synthesis in human B lymphoblasts with both hypoxanthine-guanine phosphoribosyltransferase deficiency and phosphoribosylpyrophosphate synthetase superactivity.

Human B lymphoblast lines severely deficient in hypoxanthine-guanine phosphoribosyltransferase (HGPRT) were selected for resistance to 6-thioguanine from cloned normal and phosphoribosylpyrophosphate (PP-Rib-P) synthetase-superactive cell lines and were compared with their respective parental cell lines with regard to growth and PP-Rib-P and purine nucleotide metabolism. During blockade of purine synthesis de novo with 6-methylthioinosine or aminopterin, inhibition of growth of all HGPRT-deficient cell lines was refractory to addition of Ade at concentrations which restored substantial growth to parental cell lines. Ade-resistant inhibition of growth of parental lines by 6-methylthioinosine, however, occurred during Ado deaminase inhibition. Insufficient generation of IMP (and ultimately guanylates) to support growth of lymphoblasts lacking HGPRT activity and blocked in purine synthesis de novo best explained these findings, implying that a major route of interconversion of AMP to IMP involves the reaction sequence: AMP----Ado----Ino----Hyp----IMP. PP-Rib-P generation and purine nucleoside triphosphate pools were unchanged by introduction of HGPRT deficiency into normal lymphoblast lines, in agreement with the view that accelerated purine synthesis de novo in this deficiency results from increased availability of PP-Rib-P for the pathway. Cell lines with dual enzyme defects did not differ from PP-Rib-P synthetase-superactive parental lines in rates of PP-Rib-P and purine synthesis despite 5-6-fold increases in PP-Rib-P concentrations, excretion of nearly 50% of newly synthesized purines, and diminished GTP concentrations. Fixed rates of purine synthesis de novo in PP-Rib-P synthetase-superactive cells appeared to reflect saturation of the rate-limiting amidophosphoribosyltransferase reaction for PP-Rib-P. In combination with accelerated purine excretion, increased channeling of newly formed purines into adenylates, and impaired conversion of AMP to IMP, fixed rates of purine synthesis de novo may condition cell lines with defects in HGPRT and PP-Rib-P synthetase to depletion of GTP with consequent growth retardation.

Aminopterin↗

PubMed1992

Interferon-alpha in lupus psychosis.

OBJECTIVE: Since the level of interferon-alpha (IFN alpha) is increased in the sera of patients with active systemic lupus erythematosus (SLE) and is detectable in the cerebrospinal fluid (CSF) of some SLE patients with neuropsychiatric manifestations, we investigated the contribution of IFN alpha to the pathogenesis of the neuropsychiatric manifestations of SLE. METHODS: IFN alpha levels were quantitated by radio-immunoassay in CSF and serum samples from 17 SLE patients with neuropsychiatric manifestations and 28 patients with SLE alone or SLE and other neurologic disorders. RESULTS: Levels of IFN alpha were increased in the CSF of 5 of 6 patients with lupus psychosis, and in 4 of these 5 patients, the levels in CSF were higher than those in serum. IFN alpha levels decreased when the manifestation of lupus psychosis subsided. In contrast, IFN alpha levels in CSF samples from patients with seizures alone were not increased. One patient with lupus psychosis died of complications of generalized seizures resulting from the SLE. At autopsy, we investigated whether IFN alpha protein or messenger RNA was detectable in the subject's brain. IFN alpha protein was immunohistochemically demonstrated in the neurons and in the microglia (focal accumulation), features not present in the brain tissues of subjects who died of other diseases. CONCLUSION: These findings support the hypothesis that IFN alpha, possibly synthesized in the brain, is the cause of the manifestation of psychosis in patients with SLE.

Brain↗

PubMed1992

Preparation of N-acetylneuraminic acid from delipidated egg yolk.

Egg yolk, a large proportion of the egg, was studied for the preparation of N-acetylneuraminic acid (Neu5Ac). The delipidated hen egg yolk (DEY; 500 kg containing 0.2% w/w, Neu5Ac) was hydrolysed with HCl (pH 1.4) at 80 degrees C and neutralized with NaOH (pH 6.0). The mixture was filtered and electrodialysed until the conductivity was 240 microS cm-1. The filtrate was applied on a column of Dowex HCR-W2 (20-50 mesh), followed by a column of Dowex 1-X8 (200-400 mesh). The latter column was washed with water, and then eluted with a linear gradient of HCO2H (0-2 M). The eluates containing Neu5Ac were concentrated using a reverse osmosis membrane and, finally, rotary evaporated at 40 degrees C. The residue was then lyophilized to yield 500 g Neu5Ac. The purity of Neu5Ac was > 98% (TBA method). HPLC, NMR spectroscopy and TLC chromatography of the product obtained from the DEY showed that Neu5Ac was the sole derivative present in egg yolk. The DEY, a byproduct from egg processing plants, was found to be an excellent source for the large-scale preparation of Neu5Ac.

Amino Acids↗

PubMed1992

Recurrent and acquired hepatitis C viral infection in liver transplant recipients.

To examine the postliver transplant recurrence of hepatitis C virus (HCV) infection in patients with pretransplant infection, as well as its acquisition in patients without prior infection, we used the polymerase chain reaction to amplify HCV RNA in serum and/or liver samples of 89 patients with alcoholic and cryptogenic cirrhosis undergoing liver transplantation. Results were correlated with histologic findings from posttransplant liver biopsies. Ninety-five percent of patients with pretransplant infection had posttransplant viremia. In contrast, 35% of patients without pretransplant infection acquired the virus (P less than 0.0001). Pretransplant HCV infection predisposed patients to hepatitis in the new graft. HCV RNA was present in serum of 96% of patients with posttransplant hepatitis. Fifty-six percent of patients with posttransplant HCV infection had no evidence of liver damage at least 1 year posttransplant. However, of those patients with histologic hepatitis, chronic active hepatitis was common. It is concluded that although HCV infection recurs posttransplant in almost all infected patients, acquisition of the HCV infection with transplant is common. Pretransplant HCV infection is an independent risk factor for the development of posttransplant hepatitis. HCV infection accounts for the majority of posttransplant hepatitis not due to cytomegalovirus, and although many patients with posttransplant viremia have little evidence of histologic hepatitis, significant hepatic damage may occur.

Base Sequence↗

PubMed1992

Electrophysiological effects of phencyclidine and the sigma agonist ditolylguanidine in the cerebellum of the rat.

The electrophysiological actions of phencyclidine (PCP) and the sigma agonist 1,3-di(2tolyl)guanidine (DTG) were examined in the cerebellum of urethane-anesthetized rats. The object of the study was to determine if PCP and sigma agonists shared a common mechanism of action. The cerebellar Purkinje neuron was chosen because it has sigma receptors but not N-methyl-D-aspartate receptors, where PCP has additional effects. Both DTG and PCP decreased the spontaneous discharge rate of cerebellar Purkinje neurons after parenteral administration. When the drugs were applied locally to single Purkinje neurons, using pressure ejection through multibarrel micropipettes, both compounds decreased the spontaneous activity of the neurons with equal potency. Previous studies have shown that the actions of PCP in the cerebellum are dependent upon an interaction with noradrenergic terminals from the nucleus locus coeruleus. A similar finding was made in this study for DTG. Elimination of the noradrenergic input by lesion with the neurotoxin, 6-hydroxydopamine, diminished equally the effects of PCP and DTG. Treatment of the animals with haloperidol had similar effects. It is concluded that PCP and the sigma agonist DTG both act as indirect noradrenergic agonists in the cerebellum.

Animals↗

PubMed1992

Epidemiology of measles immunity in a population of healthcare workers.

OBJECTIVE: To evaluate epidemiologic factors that can be used to predict lack of measles immunity in healthcare workers. DESIGN: During mandatory screening of employees for measles antibody, a questionnaire was used to collect demographic information. SETTING: Inpatient hospital, acute care clinics, and skilled nursing facility of a health maintenance organization. PARTICIPANTS: Employees of all ages and occupations. RESULTS: Measles immunity could not be predicted from history of measles disease and vaccination, gender, or birthplace. Of nonimmune employees, 63.7% were in the 20- to 29-year-old age group and 26.5% were in the 30- to 39-year-old age group. CONCLUSIONS: Age is the most clinically significant predictor of measles antibody, especially in persons born after 1950, who make up a large group susceptible to measles.

Adolescent↗

PubMed1992

Structure of dietary pectin, iron bioavailability and hemoglobin repletion in anemic rats.

The effects of the degree of esterification (DE) and the molecular weight (MW) of pectins on iron bioavailability were investigated in anemic rats. The pectins prepared differed (in DE and MW, respectively) as follows: P-A (73%, 860,000), P-B (75%, 89,000), P-C (22%, 1,260,000) and P-D (24%, 114,000). Rats were fed an iron-deficient diet (8 mg Fe/kg diet) for 14 d. The anemic rats were then fed a ferrous sulfate-supplemented basal diet (47 mg Fe/kg diet) or the basal diet containing one of the pectins (80 g/kg diet) for 10 d. None of the pectins used caused any significant reduction in the bioavailability of ferrous sulfate. Addition of pectin P-B to the diet resulted in significantly greater iron repletion. Compared with control rats fed with ad libitum access or pair-fed, rats fed P-B showed higher (P < 0.05) hemoglobin regeneration efficiency, hematocrit, serum iron concentration, and transferrin saturation, and lower unsaturated iron-binding capacity and total iron-binding capacity. Pectins P-A and P-D also slightly improved the hematological indices compared with P-C and control. The observed effects were dependent on the physicochemical properties of each pectin as determined by its MW and DE.

Anemia, Hypochromic↗

PubMed1992

A novel light-regulated promoter is conserved in cereal and dicot chloroplasts.

The chloroplast psbD-psbC genes encode D2 and cp43, a reaction center protein and chlorophyll-binding antenna protein of photosystem II, respectively. We have previously shown that differential accumulation of light-induced psbD-psbC mRNAs in barley chloroplasts is due to transcription from a blue light-responsive promoter (LRP). It is hypothesized that the light-induced mRNAs help to maintain levels of the D2 polypeptide, which is photodamaged and degraded in illuminated plants. To determine if light-induced accumulation of psbD-psbC mRNAs was a conserved phenomenon in chloroplasts, the expression of psbD-psbC operons from five cereals (barley, wheat, rice, maize, and sorghum) and three dicot (tobacco, spinach, and pea) species was examined. Cereal and dicot psbD-psbC operons differ due to several DNA rearrangements that moved psbK-psbI proximal to psbD-psbC, allowing cotranscription of these genes and production of several unique transcripts in cereals. Despite differences in the structure and expression of the cereal and dicot psbD-psbC operons, the accumulation of light-induced psbD-psbC mRNAs was conserved in all species studied. An unusual feature of the light-induced mRNAs was the occurrence of 5' end microheterogeneity. The multiple 5' termini were mapped to several consecutive nucleotides (8 to 25 bp) within a highly conserved (61%) DNA region that represents the transcription initiation site for the mRNAs in barley and tobacco. The novel LRP differs in sequence from typical plastid promoters that have prokaryotic "-10" and "-35" elements and is centered 570 bp (cereals), 900 bp (tobacco, spinach), or 1100 bp (pea) upstream from the psbD translational start codon. We propose that physiological and gene regulatory demands of the chloroplast act as constraints that preserved the linkage of the LRP with psbD despite DNA inversions involving the psbD upstream region.

Base Sequence↗

PubMed1992

Absorption of polar drugs following caecal instillation in healthy volunteers.

We have investigated colonic drug absorption in man by the caecal instillation of a multi-component solution of atenolol, cimetidine, frusemide, hydrochlorothiazide and salicylic acid. We found that salicylic acid absorption from this solution was delayed but complete whereas the absorption of atenolol, cimetidine, frusemide and hydrochlorothiazide was four- to five-fold lower than expected from oral bioavailability studies.

Adult↗

PubMed1992

The influence of gastrointestinal transit on drug absorption in healthy volunteers.

1. The effect of variability of gastric emptying and oro-caecal transit on the absorption of a multicomponent solution of frusemide, atenolol, hydrochlorthiazide and salicylic acid has been studied in six healthy subjects. Each subject was studied on five separate occasions: three times under basal conditions, once following metoclopramide and once following codeine pretreatment in an attempt to speed and slow transit respectively. 2. Inter-subject variability of gastric emptying, oro-caecal transit and the rate and extent of drug absorption was considerable. 3. The absorption of salicylic acid appeared rate-limited by gastric emptying but the rate and extent of frusemide, atenolol and hydrochlorthiazide absorption were unrelated to measures of gastric emptying or oro-caecal transit. 4. Codeine phosphate caused a two-fold delay in oro-caecal transit but did not influence gastric emptying while metoclopramide had no significant effect on either function. 5. Metoclopramide and codeine had no significant effect on the rate or extent of absorption of any of the study drugs. 6. Within the limits of this experiment, oro-caecal transit time did not appear to be an important determinant of frusemide, atenolol, hydrochlorothiazide or salicylic acid absorption. Other factors must account for the observed variability in drug absorption.

Administration, Oral↗

PubMed1992

Effects of a non-absorbable osmotic load on drug absorption in healthy volunteers.

1. We have studied the effects of a non-absorbable osmotic load on the absorption of a multicomponent solution of frusemide, atenolol, hydrochlorothiazide and salicylic acid in six healthy volunteers. 2. Each subject was studied on up to four separate occasions. The drugs were administered in one of four solutions: a) a mannitol/electrolyte solution, b) a double-strength mannitol/electrolyte solution, c) a glucose/electrolyte solution and d) water. Lactulose or sulphasalazine were added as oro-caecal transit markers. Lactulose was included in the mannitol- and glucose-based solutions, adding a further non-absorbable osmotic load, and sulphasalazine was added to the water, adding little osmotic load. 3. The absorption of atenolol and hydrochlorothiazide was two- to three-times less from all lactulose-containing solutions than from the sulphasalazine-containing solution. The absorption of frusemide and salicylic acid was similar from all four solutions. 4. The largest non-absorbable osmotic load impaired the absorption of atenolol and hydrochlorothiazide most and the incorporation of glucose only partly restored absorption. 5. These results suggest that transmucosal water movement is an important determinant of atenolol and hydrochlorothiazide absorption but is less relevant for the absorption of frusemide and salicylic acid. Furthermore, these data demonstrate a previously unrecognised interaction between a commonly prescribed laxative--lactulose, and atenolol and hydrochlorothiazide.

Adult↗

PubMed1992

Two studies of the non-pharmacological treatment of menstrually-related migraine headaches.

In order to evaluate the effect of non-pharmacological treatment on menstrual and non-menstrual migraine headache (HA), 2 studies have been conducted. In Study 1 which was a retrospective examination of between group reactions to non-drug treatments, 37 self-defined menstrual migraineurs and 62 non-menstrual migraineurs showed comparable overall improvement (reduction in HA activity) after treatment, but menstrual migraineurs maintained larger usage of medication across time than non-menstrual migraineurs. In Study 2 which was a prospective examination of within subject reactions to non-drug treatments, 15 carefully documented menstrual migraineurs again showed comparable levels of overall improvement but also showed that level of menstrual headache activity remained higher across time than non-menstrual migraine HA. Because there were no interactions of time and type of migraine in either study, these results raise some questions about the existence of differential effectiveness of non-pharmacological treatment of menstrual vs non-menstrual migraine.

Adult↗

PubMed1992

Clinical effects of long-term use of neutralized dialysate for continuous ambulatory peritoneal dialysis.

The long-term effects of neutralized dialysate used in continuous ambulatory peritoneal dialysis (CAPD) were evaluated in 8 well-controlled patients. Twelve milliliters of 8.4% sodium bicarbonate was added to Dianeal PD-1 immediately before every administration. The final pH was 6.8 and the concentration of sodium bicarbonate was 6 mmol/l. The final sodium level was 138 mEq/l. This dialysate was used for 5 months. For 2 months before and 3 months after this period, Dianeal PD-2 was used as the dialysate for comparison. Blood bicarbonate levels significantly improved during the use of the neutralized dialysate. Blood sodium, chloride and magnesium levels and the effluent volume significantly increased. Sodium balance improved during the period when neutralized dialysate was used. Total leukocyte counts in the effluent decreased, and leukocyte viability increased. Abdominal distention, abdominal pain during instillation, nausea and headache improved. No side effects, including peritonitis, occurred during the trial of neutralized dialysate. The results suggest that this dialysate was less irritating to the peritoneal membrane than the control dialysate and that the therapeutic effects were satisfactory.

Blood Urea Nitrogen↗

PubMed1992

Intervention program for obese school children.

The purpose of this study was to implement and evaluate a program for obese school children. A pretest-posttest design was utilized. Data was collected related to weight status, skinfold measurements, self-esteem, and nutritional knowledge. A convenience sample of 26 children, in the fourth to sixth grades, completed this 9-week program. The results indicate that self-esteem increased significantly (p less than .001) between the pretest and posttest interval. Weight status and nutritional knowledge showed no improvement. Exercise was difficult to assess on self-report, therefore no conclusions were were drawn in relation to this variable. Future research will be directed toward refining this intervention program.

Child↗

PubMed1992

An improved high-performance liquid chromatographic assay for the determination of pyridinoline in connective tissues.

A high-performance liquid chromatographic (HPLC) method for determination of pyridinoline and its application to connective tissues are described. The chromatographic separation was accomplished by using Inertsil ODS-2 column and a mixture of 0.1 M sodium phosphate and acetonitrile (75:25, v/v) containing sodium dodecyl sulfate (SDS) and ethylenediamine tetraacetic acid (EDTA) as eluent. The chromatogram was developed isocratically and the eluted components were monitored with excitation at 295 nm and emission at 395 nm. The pyridinoline in crude hydrolysate of connective tissues can be determined in 5 min, with as little as 1 pmol of sample. The present method is rapid, simple and can be used for the routine analysis of connective tissues such as cartilage, bone, Achilles tendon and aorta.

Amino Acids↗

PubMed1992

Oncogene and growth factor expression in MEN 2 and related tumors.

Pheochromocytomas occur sporadically or in individuals affected by inherited syndromes including multiple endocrine neoplasia (MEN) type 2A and 2B, neurofibromatosis, and the von Hippel-Lindau syndrome (vHL). Medullary thyroid carcinomas (MTCs) also occur sporadically or as part of MEN 2A, MEN 2B, and familial MTC. Little is known of the molecular genetic background of these tumors. We have shown previously that activation of the N-ras, H-ras, and K-ras oncogenes does not occur in these tumors, but that deletions of the short arm of chromosome 1 are extremely common (> 60%) and may indicate loss of a suppressor gene in the chromosomal region 1p31-36. We have examined the structure and expression of N-myc, c-myc, L-myc, c-mos, nerve growth factor (beta-NGF), and the low affinity nerve growth factor receptor (LNGFR) in a series of pheochromocytomas and MTCs from patients with hereditary and sporadic diseases. Southern analysis, using radiolabeled DNA probes, revealed no evidence of amplification or rearrangement of these genes in any normal or tumor tissues except for loss of heterozygosity at the L-myc locus (1p32) in 9 pheochromocytomas from patients with MEN 2A or MEN 2B, in 5 of 11 non-MEN pheochromocytomas, and in 3 of 24 non-MEN MTCs. Gene expression at the RNA level was examined by Northern analysis or ribonuclease protection assay (RPA) using radiolabeled DNA or cRNA probes. C-myc transcripts were detectable at low levels in all tumors tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗