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Biomedical subjects

K Hsu

Publications and source records attributed to K Hsu.

At least 73 records · Page 4Linked to original sources
PubMed1989

Transurethral ureterorenoscopic ureteral stone removal in 100 patients.

A total of 102 transurethral ureterorenoscopic stone manipulations were performed on 100 patients with ureteral stones. Among the 81 successful procedures, stones were removed using a stone basket under ureterorenoscopic control in 12 (14.8%), after ultrasonic disintegration in 58 (71.6%), and stone fragments were allowed to be spontaneously passed after ultrasonic disintegration in 11 (13.6%). Owing to improvements in available instruments, transurethral ureterorenoscopic removal of ureteral stones will become an important procedure to endourologists. This report describes transurethral ureterorenoscopic removal of ureteral stones in 100 patients.

Adolescent↗
PubMed1989

Lack of effect of a neurotoxin from the scorpion Buthus martensi Karsch on nerve fibers of this scorpion.

A neurotoxin (BmK I) was purified from the venom of the scorpion species Buthus martensi Karsch. Effects of this toxin on the excitability of the abdominal nerve fibers of the same scorpion were examined. The toxin had no effect at all on the action and resting potentials recorded intracellularly even at a concentration as high as 100 microM. A similar result was obtained through optical measurements of the action potential using a potential sensitive dye. Sea anemone toxin II (8 microM) had no effect on nerve excitability either. However, tetrodotoxin (50 nM) reversibly suppressed the action potential and grayanotoxin II (20 microM) induced a sustained depolarization of the nerve membrane which resulted in a reversible suppression of the action potential. BmK I at a concentration of 0.1 microM greatly prolonged the action potential in the crayfish giant axon. We conclude that the Na channel of nerve fibers of this scorpion is totally insensitive to the neurotoxin in this scorpion's venom.

Animals↗
PubMed1989

Occult infections causing persistent low-back pain.

Occult infections caused by indolent organisms may produce persistent back pain that may be difficult to diagnose. The usual findings considered indicative of spinal infection are not reliable in these cases. The authors describe nine patients who presented with occult infections of the lumbar spine. Two of the nine had no antecedent lumbar surgeries nor open wounds. The predominant organisms were diptheroids and coagulase-negative staphylococci. The diagnosis was established by the clinical course, pathologic tissue changes at surgery, cultures, and response to antibiotic therapy. Normal Westergren sedimentation rates were noted in seven of nine patients, and normal white blood cell counts in six of nine patients. With the exception of two positive computed tomography (CT) scans, one positive gallium scan, and one positive magnetic resonance imaging (MRI) scan, all remaining imaging studies were negative for infection. In many cases, the infection neither was limited to nor involved the disc space.

Abscess↗
PubMed1989

Drosophila mutants with progressive atrophy in dorsal longitudinal muscles.

We have characterized six chemically induced mutations of the Drosophila dlm-defective (d l m d) gene. The mutants are flightless, but they have an otherwise normal appearance. By electron microscopic examination, a focal atrophy was found in their dorsal longitudinal muscle (DLM) fibers, but no abnormalities in nerve conduction or synaptic transmission were detected by electrophysiological tests. The nerve-evoked muscle spike also seemed to be normal, except that the resting potential of DLM in mutant flies was lower and their membrane excitability was higher than those in the wild type flies. The possible causes of the DLM degeneration in this strain are discussed.

Alleles↗
PubMed1989

[The measurement of airway responsive index in normal individuals and asthmatic patients].

Measurement of airway responsiveness to nonallergenic stimuli can be used to confirm the diagnosis of asthma, document the severity of airway responsiveness, and follow changes in airway responsiveness with time in relation to treatment or exposure to occupational sensitizers. Methacholine inhalation is the preferred test for the clinical laboratory as it is more sensitive than exercise or cold air, and there are fewer side effects than with histamine. Airway responsiveness to nonspecific, pharmacologic, bronchoconstricting stimuli has been described using various methods of summarizing dose-response data. The purpone of this study was to examine a simple index of nonspecific airway responsiveness to methacholine, i.e., the slope of a straight line approximation of the dose-response curve. Twelve normal and 19 asthmatic volunteers were studied. Subjects underwent a standard methacholine challenge test, both specific airway conductance (SGaw) and forced expiratory volume of one second (FEV1) were measured. We examined the relationship between response assessed by SGaw or FEV1 and dose of methacholine in each subject. The results showed that, in most of the subjects, the decline of pulmonary function with increasing dose of methacholine almost followed a simple linear relationship. A straight line extending from the origin to the last data point obtained approximating this relationship provides a reasonable summary of each plot. This were true not only in asthmatic subjects but also in normals, and not only for FEV1 but also for SGaw. The slope of this straight line was denominate as responsive index. The summary dose-response slope effectively separated asthmatic from normal subjects without any overlapping; this was true not only when FEV1 but also for SGaw was used as the parameter of response. The responsive index was much greater among asthmatics than among normal subjects (P less than 0.001). The responsive index from the parameter of SGaw was nearly perfectively correlated with which was from FEV1 (r = 0.989, P less than 0.001). We considered that airway responsive index can be calculated not only when FEV1 but also SGaw was used as a parameter of pulmonary function response. The dose-response slope calculated in the present analysis is a summary of the overall dose-response relationship and thus differs from the slope of the latter part of the log dose-response curve. It has the advantage of providing a single, continuous, easily interpreted measure of responsiveness for all subjects.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1988

Early results of spinal fusion using variable spine plating system.

Seventy-seven consecutive patients underwent application of variable spine plating (VSP) spinal plates between August 1984 and October 1985. Sixty-four percent had previous procedures at the same level or levels operated. Operative indications were spinal stenosis, segmental instability, unstable spondylolisthesis, herniated disc with instability, pseudoarthrosis, unstable fracture, and failed surgery syndrome with evidence of one of the preceding. Overall results showed 30% excellent, 30% good, 34% fair, 6% poor. There were four deep wound infections and 19 patients with one or more broken screws. Screw alignment and the angular relationship of each screw to the spinal plate are considered important technical factors in minimizing screw failure. Vigorous distraction of the vertebrae using interpedicular screws is rarely indicated. Twenty-four patients required reoperation. We feel the procedure is relatively indicated in cases of moderate to severe instability, such as some cases of spondylolisthesis, failed surgery with marked segmental instability, the obese, deconditioned patient, or cases of spinal stenosis rendered very unstable by surgical decompression, and most strongly indicated in unstable lumbar and thoracolumbar fractures.

Adult↗
PubMed1988

Normal magnetic resonance imaging with abnormal discography.

In degenerative lumbar spine disease, recent studies have supported the clinical usefulness of discography, especially when used with computed tomography (CT) scanning. The role and capabilities of magnetic resonance imaging (MRI) scanning are currently evolving and being defined. This study reviews a series of patients with prolonged disabling symptoms who had normal MRI scans and abnormal discography. Discograms and discogram-CT scans may at times allow detection of clinically correlative and significant pathology (usually annular disruptions) not suggested by MRI scanning. This fact should be considered in patients with normal MRI scanning and continuing unexplained symptomatology.

Adult↗
PubMed1988

Purification and the partial amino acid sequence of an insect neurotoxin from the venom of scorpion Buthus martensi Karsch.

1. A neurotoxic peptide was isolated from the venom of the scorpion Buthus martensi Karsch collected in Henan Province, China. 2. This toxin showed the highest neurotoxic potency to crickets amongst all components in the venom examined. 3. The amino acid composition of the toxin was similar to that of insect toxin 1 of Leiurus quinquestriatus quinquestriatus. 4. The partial primary sequence of the toxin at the N-terminal was very similar to that of an insect toxin of Androctonus australis Hector. 5. We conclude that the neurotoxin we isolated is indeed an insect toxin and thus named it as BmK IT.

Amino Acid Sequence↗
PubMed1987

Dielectric properties of adsorption/ionization site of pentachlorophenol in lipid membranes.

The results of three complementary studies focused on characterization of the local environment of the common pesticide pentachlorophenol (PCP) adsorbed to phosphatidylcholine (PC) and phosphatidylglycerol (PG) membranes are reported. The effect of cholesterol (Chol) was examined. These studies included: Measurements of solvatochromic shifts of the ultraviolet absorption spectra of PCP in membranes and in polar non-hydrogen-bonding (a red shift) and hydrogen-bonding (a blue shift) solvents. Pi-pi transition energies were analyzed in terms of the dielectric cavity models of Onsager, Block-Walker, which includes dielectric saturation, and a soft dipole model of Suppan, which accounts for PCP's polarizability. The estimates of dielectric constant of the PCP adsorption site yielded 8.1-8.7 for the PC and 16.8-20.1 for PG membranes. Solvatochromic effects indicate hydrogen bonding between the membrane-bound ionized PCP molecule and water, which is enhanced by the presence of cholesterol. Determinations of the pKa of PCP adsorbed to PC, PG, PC/Chol, PG/Chol membranes and dissolved in dioxane-water solutions of a known dielectric constant. The pKa value of PCP adsorbed to membranes was always greater than the standard pKa value and it increased with the membrane's negative charge. The pKa value sequence in 0.1 M KCl was 6.68 (PG), 6.32 (PG/Chol = 70:30 mole fractions), 5.97 (PC), and 5.75 (PC/Chol = 70:30). The intrinsic pKa values of PCP in membranes were 5.2-5.4 (PG) and 5.5-6.0 (PC). Estimates of the dielectric constant of PCP's ionization site in membranes yielded 10-22 (PC) and 27-37 (PG). Cholesterol facilitated the release of the hydrogen ion from membrane-bound PCP. Measurements of pH dependence of PCP-induced membrane electrical conductivity. pH values of conductivity maxima were always greater than the standard pKa of PCP, and their sequence corresponded to that of the pKa values of membrane-bound PCP. The anomalous properties of PCP as a Class 2 uncoupler are due to PCP's lipophilic character. In response to a low dielectric constant of the adsorption/ionization site, the physicochemical characteristics of PCP adsorbed to membranes are different from the standard values--a fact that needs to be taken into account in the development of models of PCP's toxicity.

Adsorption↗
PubMed1987

Prevalence of depression and distress in a large sample of Canadian residents, interns, and fellows.

Using data from 1,805 interns, residents, and fellows in Ontario, Canada, the authors report the prevalence of symptoms measured by the Center for Epidemiologic Studies Depression Scale (CES-D). They found that the proportion of subjects scoring as depressed was somewhat higher than that found in community studies. Women had higher depression scores than men. The proportion of unmarried house staff with moderate or severe depression scores was higher than that of married house staff. Considerable differences were found by specialty, and depression was most prevalent in the first year of postgraduate training. These findings have implications for those who direct postgraduate medical training or who seek to alleviate unnecessary stress in the postgraduate education experience.

Adult↗
PubMed1987

Effects of neutrophils on collateral ventilation and peripheral lung reactivity in dogs.

We studied the effects of neutrophil activation on collateral ventilation and peripheral lung reactivity in anesthetized dogs. A fiberoptic bronchoscope was wedged into a segmental airway under direct vision. Ventilation beyond the obstruction thus occurred only through collateral channels. Through one lumen of a double-lumen catheter threaded through the suction port of a bronchoscope, 5% CO2 in air was infused at a known constant rate (V coll). Through the other lumen, pressure at the tip of the bronchoscope was monitored (Pb). For measurements of resistance to flow through the collateral system (Rcs), the ventilation was stopped at functional residual capacity (FRC). Histamine was delivered through the bronchoscope to the obstructed lung segment in the form of an aerosol mist generated by an ultrasonic nebulizer. Measurements of Rcs were used as a parameter of the peripheral lung reactivity to histamine challenge. Within one hour after intravenous infusion of phorbol myristate acetate (PMA), a neutrophil activator, the reactivity to histamine significantly increased. After this, Rcs increased even without histamine challenge. This increase may have been due to an edematous injury of lung caused by PMA. The nature of the injury was confirmed by wet to dry weight ratios. In the other group, the white cell count dropped below 1000 per cu. mm. after intravenous infusion of nitrogen mustard. The same experimental protocols were followed. The Rcs did not increase even with histamine challenge. Our results suggested that substances such as oxygen radicals and arachidonic acid metabolites, which can be released by activated neutrophils, may not not only increase peripheral lung reactivity, but may also induce pulmonary edema.

Airway Resistance↗