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Biomedical subjects

S Bak

Publications and source records attributed to S Bak.

At least 37 records · Page 2Linked to original sources
PubMed1997

MR imaging of the wrist in carpal tunnel syndrome.

PURPOSE: To determine whether specific parameters measured on MR images correlated to electrophysiological changes in carpal tunnel syndrome (CTS). MATERIAL AND METHODS: Prospective clinical examinations were made of 20 patients with suspected CTS. We performed bilateral electrophysiological examinations of the median nerve and bilateral MR imaging of the wrists. RESULTS: The electrophysiological examination suggested median nerve entrapment in 18 wrists. These wrists were compared to the remaining 22 electrophysiologically normal wrists. In addition, we compared both wrists in 12 patients with unilateral symptoms of CTS without reference to the electrophysiological findings. We found no difference in specific MR parameters between the 2 groups. CONCLUSION: Neither symptoms nor electrophysiological findings in CTS were related to specific MR parameters.

Carpal Bones↗
PubMed1997

Isolation and reconstitution of cytochrome P450ox and in vitro reconstitution of the entire biosynthetic pathway of the cyanogenic glucoside dhurrin from sorghum.

A cytochrome P450, designated P450ox, that catalyzes the conversion of (Z)-p-hydroxyphenylacetaldoxime (oxime) to p-hydroxymandelonitrile in the biosynthesis of the cyanogenic glucoside beta-D-glucopyranosyloxy-(S)-p-hydroxymandelonitrile (dhurrin), has been isolated from microsomes prepared from etiolated seedlings of sorghum (Sorghum bicolor L. Moench). P450ox was solubilized using nonionic detergents, and isolated by ion-exchange chromatography, Triton X-114 phase partitioning, and dye-column chromatography. P450ox has an apparent molecular mass of 55 kD, its N-terminal amino acid sequence is -ATTATPQLLGGSVP, and it contains the internal sequence MDRLVADLDRAAA. Reconstitution of P450ox with NADPH-P450 oxidoreductase in micelles of L-alpha-dilauroyl phosphatidylcholine identified P450ox as a multifunctional P450 catalyzing dehydration of (Z)-oxime to p-hydroxyphenylaceto-nitrile (nitrile) and C-hydroxylation of p-hydroxyphenylacetonitrile to nitrile. P450ox is extremely labile compared with the P450s previously isolated from sorghum. When P450ox is reconstituted in the presence of a soluble uridine diphosphate glucose glucosyltransferase, oxime is converted to dhurrin. In vitro reconstitution of the entire dhurrin biosynthetic pathway from tyrosine was accomplished by the insertion of CYP79 (tyrosine N-hydroxylase), P450ox, and NADPH-P450 oxidoreductase in lipid micelles in the presence of uridine diphosphate glucose glucosyltransferase. The catalysis of the conversion of Tyr into nitrile by two multifunctional P450s explains why all intermediates in this pathway except (Z)-oxime are channeled.

Amino Acid Sequence↗
PubMed1997

A clinical trial of dextromethorphan in amyotrophic lateral sclerosis.

INTRODUCTION: Although the cause of amyotrophic lateral sclerosis (ALS) is unknown, excitotoxicity mediated by glutamate has been implicated. Dextromethorphan is a NMDA-glutamate receptor antagonist with neuroprotective properties. MATERIAL AND METHODS: The effect of treatment with dextromethorphan (150 mg daily) in ALS patients was evaluated in a randomized, double-blind, placebo-controlled study. Forty-five patients were included in the analysis. RESULTS: At the end of the treatment period, 12 months after randomization, 15 patients (65%) in the placebo group and 12 patients (55 %) in the dextromethorphan group were still alive (log rank test, P=0.49). Rates of disease progression, as expressed by rates of decline in pulmonary function and in functional disability, were similar in both groups except for a significantly less pronounced rate of decline in the ability scores for the lower extremities in the dextromethorphan group. CONCLUSION: Treatment with a relatively low dose of dextromethorphan did not result in an improvement in 12-month survival in ALS.

Adult↗
PubMed1997

Development of an ostomy competency.

Staff educators and staff nurses developed an ostomy competency, with the guidance and expertise of the advanced practitioner and enterostomal nurse at a large teaching hospital. The competency improved the quality of care for surgical ostomy patients. Care was standardized and staff nurses' clinical knowledge was enhanced. Following the sessions, staff nurses verbalized increased confidence in working with patients with ostomies and demonstrated increased autonomy and problem-solving abilities. No variances in educational aspects of care were noted on clinical pathways.

Clinical Competence↗
PubMed1996

Isolation and reconstitution of the heme-thiolate protein obtusifoliol 14alpha-demethylase from Sorghum bicolor (L.) Moench.

The heme-thiolate (cytochrome P450) enzyme which catalyzes the 14alpha-demethylation of obtusifoliol has been isolated from microsomes prepared from etiolated seedlings of Sorghum bicolor (L.) Moench. The obtusifoliol 14alpha-demethylase is a key enzyme in plant sterol biosynthesis and a target for the design of phyla-specific sterol 14alpha-demethylase inhibitors. Microsomal cytochrome P450s were solubilized by using the detergents Renex 690 and reduced Triton X-100, and the obtusifoliol 14alpha-demethylase was isolated by DEAE ion exchange and dye affinity column chromatography. The isolated enzyme has an absorption spectrum characteristic for low spin cytochrome P450s and produces a Type I binding spectrum with obtusifoliol as substrate. Binding spectra were not obtained with lanosterol, campesterol, sitosterol, or stigmasterol. Obtusifoliol 14alpha-demethylase has an apparent molecular mass of 53 kDa and is estimated to constitute approximately 20% of the total cytochrome P450 content of the microsomal membranes and about 0.2% of the total microsomal protein. Gas chromatography-mass spectrometry analysis of reconstitution experiments with dilauroylphosphatidylcholine micelles containing isolated obtusifoliol 14alpha-demethylase and sorghum NADPHcytochrome P450 oxidoreductase demonstrated the conversion of obtusifoliol (4alpha,14alpha-dimethyl-5alpha-ergosta-8, 24(28)-dien-3beta-ol) to 4alpha-methyl-5alpha-ergosta-8,14, 24(28)-trien3beta-ol, the 14alpha-demethylated product of obtusifoliol with a double bond introduced at the Delta14 position. The N-terminal amino acid sequence of the protein is MDLADIPQ/KQQRLMAGXALVV. Five internal sequences were obtained after endoproteinase Lys-C and Glu-C digestion. The fragment AAGAFSYISFGGGRH aligns with the unique heme binding domain of mammalian and yeast sterol 14alpha-demethylases which belong to the CYP51 family. Therefore it is conceivable that the obtusifoliol 14alpha-demethylase from plants also belongs to the CYP51 family, the only P450 family so far known to be conserved across the phyla.

Carbon Monoxide↗
PubMed1996

Why are most drowning victims men? Sex differences in aquatic skills and behaviors.

Men have higher drowning rates than women for most age groups. Data from a 1991 national household survey (n = 3042) on aquatic activities were used to examine hypotheses about differential drowning rates by sex. Men and women were compared by (1) exposure to aquatic environments; (2) frequency of aquatic activities involving or potentially involving, submersion; (3) swimming training and ability; (4) aquatic risk-taking behaviors; and (5) alcohol use on or near the water. Men had elevated risks for exposure, risk taking, and alcohol use. It was concluded that several factors contribute to their relatively high drowning rates, including a possible interaction between overestimation of abilities and heavy alcohol use.

Adolescent↗
PubMed1996

Parents and procedures: a randomized controlled trial.

INTRODUCTION: Previous work has shown that parents prefer to be present when their children undergo common invasive procedures, although physicians are ambivalent about parental presence. PURPOSE: To determine the effect of a parent-focused intervention on the pain and performance of the procedure, anxiety of parents and clinicians, and parental satisfaction with care. POPULATION: Children younger than 3 years old undergoing venipuncture, intravenous cannulation, or uretheral catheterization. SETTING: Pediatric emergency department of Boston City Hospital. DESIGN: Randomized controlled trial with three groups; parents present and given instructions on how to help their children; parents present, but no instructions given; and parents not present. INTERVENTION: The parents were instructed to touch, talk to, and maintain eye contact during the procedure. RESULTS: A total of 431 parents was randomized to the intervention (N = 153), present (N = 147), and not present (N = 131) groups. The groups were equivalent with respect to measured sociodemographic variables and parents' previous experience in the pediatric emergency department. No differences emerged with respect to pain (3-point scale measured by parent and clinician, and analysis of cry); performance of the procedure (number of attempts, completion of procedure by first clinician, time); clinician anxiety; or parental satisfaction with care. Parents who were present were more likely to rate the pain of the children as extreme/severe (52%) in comparison to clinicians (15%, kappa .07, poor agreement) and were significantly less anxious than parents who were not present. CONCLUSION: Overall, the intervention was not effective in reducing the pain of routine procedures. Parental presence did not negatively affect performance of the procedure or increase clinician anxiety. Parents who were present were less anxious than those who were not present. CLINICAL IMPLICATION: In general, parents have indicated that they want to be present when their children undergo procedures. The results of this study challenge the traditional belief that parental presence negatively affects our ability to successfully complete procedures. We should encourage parents who want to be present to stay during procedures.

Adult↗
PubMed1995

[Prevalence of risk factors in cerebral ischemia].

The prevalence of risk factors for ischaemic stroke is described in 270 patients with transient ischaemic attacks or ischaemic stroke. Smoking was the most common risk factor (46%) followed by hypertension (30%) and increased levels of serum cholesterol (26%). Diabetes mellitus, atrial fibrillation and earlier myocardial infarction were less common risk factors. Ninety-one patients (34%) had two or more risk factors. In conclusion, vascular risk factors are frequently present in patients with transient ischaemic attacks or ischaemic stroke. It is still not yet clarified if risk factor modification is of any value in prevention of stroke recurrence.

Aged↗
PubMed1995

Gene expression of urea cycle enzymes following two-thirds partial hepatectomy in the rat.

The effect of reduction of functional liver mass on the expression of enzyme systems for hepatic urea synthesis was assessed in rats following two-thirds partial hepatectomy. Results were related to normal, fed rats and to sham-operated rats, with identical timing for surgery and feeding. Among the five urea cycle enzymes the mRNA steady-state level was higher in hepatectomized than in sham-operated rats for carbamoyl phosphate synthetase and arginino-succinate lyase. The level for albumin mRNA remained close to that of the controls. Relative transcription rates were found to be increased for carbamoyl phosphate synthetase, arginino-succinate synthase and arginase. For albumin the transcription rate was drastically reduced initially, but recovered gradually during the experimental period. The data indicate that the expression of urea cycle enzymes, in particular that of carbamoyl phosphate synthetase which is the rate-limiting step, is up-regulated by partial hepatectomy. This helps to maintain urea synthesis rate at a normal or near normal level during the period of reduced liver mass, confirming metabolic studies. In contrast, the transcription for albumin was reduced. The immediate increase in urea cycle enzyme expression during the period of acute hepatocyte loss is consistent with the view that it is vitally important that urea synthesis, in contrast to e.g. albumin synthesis, remains intact when the metabolic capacity of the liver is reduced.

Albumins↗
PubMed1994

[Symptomatic treatment of amyotrophic lateral sclerosis].

During a twelve year period 58 patients with motor neurone disease were admitted to the Department of Neurology, Odense University Hospital. The medical records were reviewed and different aspects of symptomatic treatment for these patients were recorded retrospectively. After the first admission 55% of the patients received out-patient treatment, while 31% had no further contact to the Department of Neurology. Forty-nine patients developed bulbar symptoms. Of these patients 41% were referred to a laryngologist, 27% were referred to a speech therapist and 10% to a nutritionist. Seven patients had a gastrostomy, while feeding tube was used by at least six patients. At the time of follow up 49 patients had died, 63% in hospital. At least 22 patients were treated with morphine in the last period of their lives. In order to improve the symptomatic treatment in motor neurone disease we suggest that these patients are treated at the neurological departments by interdisciplinary teams with particular interest in motor neurone disease.

Adult↗
PubMed1993

Fear of falling among the community-dwelling elderly.

To assess the incidence of falls and the prevalence, intensity, and covariates of fear of falling among community-dwelling elderly, the authors surveyed a random sample of 196 residents (> or = 58 years of age) of housing developments for the elderly in Brookline and Plymouth, Massachusetts. Forty-three percent reported having fallen in recent years, 28% in the last year. Of those who had fallen within the year prior to the interview, 65% reported injury, 44% sought medical attention, and 15% required hospitalization as a consequence of their fall(s). Fear of falling ranked first when compared to other common fears (i.e., fear of robbery, financial fears). Self-rated health status and experience of previous falls were significantly associated with fear of falling. Further analysis suggests that fear of falling may affect social interaction, independent of risks for falling.

Accidental Falls↗
PubMed1991

[Adrenomyeloneuropathy].

A case of adrenomyeloneuropathy is presented. The clinical picture is characteristic with slowly progressive spastic paraparesis, relatively mild peripheral neuropathy and adrenal insufficiency. Dietary therapy may prevent further progression of the neurologic symptoms.

Adrenoleukodystrophy↗
PubMed1990

An unidentified macromolecular inhibitory constituent of calcium oxalate crystal growth in human urine.

We have detected and isolated a macromolecular constituent in normal human urine possessing calcium crystal growth inhibitory activity. The purification procedure consisted of two anion exchange chromatographies and one affinity chromatography. The crystal growth inhibitor was found to be heterogeneous in net charge as well as in size. It has not been identified. It is not an uronic acid-containing glycosaminoglycan, hitherto presumed to be responsible for the inhibitory activity. Whether an urinary fragment of inter-alpha-trypsin inhibitor is responsible has yet to be resolved.

Calcium Oxalate↗
PubMed1990

Recombinant human tumour necrosis factor increases cytosolic free calcium in murine fibroblasts and stimulates inositol phosphate formation in L-M and arachidonic acid release in 3T3 cells.

Stimulation of murine L-M and 3T3 fibroblasts with human recombinant tumour necrosis factor (rTNF) resulted in an increase in the cytosolic free Ca2+ concentration ([Ca2+]i). In 3T3 cells rTNF also induced release and metabolization of arachidonic acid, whereas in L-M cells rTNF provoked rapid increases in the levels of inositol mono-, bis- and trisphosphates (IP1, IP2 and IP3). In these cells the Ca2+ response was also observed in Ca2+ free medium, suggesting that rTNF promotes mobilization of Ca2+ from intracellular stores. In 3T3 cells, however, Ca2+ originated from the extracellular space, since the response was abolished in medium containing 1 mM EGTA. Both rTNF-induced calcium responses were inhibited by a specific rabbit IgG antibody to rTNF but not by 1-verapamil, a blocker potential-operated calcium channels. These results suggest that increased formation of inositol phosphates, arachidonic acid release and increased cytosolic free Ca2+ are involved in the biological effects of rTNF. However, rTNF generate these signals by different mechanisms depending upon the target cell.

Animals↗
PubMed1989

[Gynecomastia. A follow-up study].

Classification of gynaecomastia as physiological/idiopathic is traditionally carried out by exclusion on the basis of the case history and results of the clinical examination. Out of 138 consecutive patients with gynaecomastia referred by general practitioners to the Surgical Gastroenterological Department K in Odense Hospital during the period 1978-1981 for treatment, 98 patients (71%) were classified in this manner. Following a period of observation ranging from four months to ten years, average 7.5 years, diseases were demonstrated in five of the physiological/idiopathic cases which were perhaps the causes of gynaecomastia. Employment of an extensive paraclinical programme of investigation would probably have resulted in demonstration of the underlying disease in three cases but would scarcely have improved the prognosis despite the possibility for earlier institution of treatment. Routine employment of extensive paraclinical investigations of selected patients with gynaecomastia of this type cannot be recommended on account of the limited diagnostic and therapeutic results. Classification of gynaecomastia based on the case history and clinical examination appears to be sufficiently exact in patients referred by general practitioners for treatment to a surgical department.

Adolescent↗
PubMed1989

Preparation of fresh frozen human sera for external quality assessment.

A procedure for preparation of unmodified and modified fresh frozen human quality testing sera is described. The materials have been used for external quality assessment in Denmark. Examples of improvements in external quality assessment schemes using this type of material are shown.

Alanine Transaminase↗
PubMed1989

Postmastectomy seroma. A study of the nature and origin of seroma after mastectomy.

To investigate the nature and origin of postmastectomy seroma, the concentration of IgG, the number of leucocytes, granulocytes and lymphocytes in the drain fluid and seroma aspirates was studied in breast cancer patients after mastectomy. The composition of the fluid and aspirates and the time-related changes of the investigated criteria suggested that 1) seroma is not an accumulation of serum, but an exudate, 2) the exudate is an element in an acute inflammatory reaction, i.e. the first phase of wound repair, and 3) seroma formation reflects an increased intensity and a prolongation of this phase. By paying attention to factors influencing the duration and intensity of the first phase of wound repair, it should be possible to reduce the occurrence of seroma.

Acute-Phase Reaction↗