Biomedical subjects

K C Lin

Publications and source records attributed to K C Lin.

At least 55 records · Page 3Linked to original sources

PubMed1998

Ultrastructural morphology of Enterocytozoon bieneusi in biliary epithelium of rhesus macaques (Macaca mulatta).

Enterocytozoon bieneusi is the most common microsporidian parasite found in humans with acquired immunodeficiency syndrome. A nearly identical organism was recently recognized in rhesus macaques (Macaca mulatta). Ultrastructural examination of this microsporidian parasite in biliary epithelium of rhesus macaques reveals characteristics unique to E. bieneusi, including 1) a lack of sporophorus vesicles or pansporoblastic membranes, 2) direct contact of all stages with the host-cell cytoplasm, 3) elongated nuclei present within proliferative and sporogonial stages, 4) late thickening of the sporogonial plasmodium plasmalemma, 5) electron-lucent inclusions present throughout the life cycle, 6) precocious development of electron dense discs before plasmodial division to sporoblasts, and 7) the presence of polar tube doublets within spores and sporoblasts visualized as 5-7 coils in section.

Animals↗

PubMed1998

Acute fulminant sarcocystosis in a captive-born rhesus macaque.

A captive-born juvenile female rhesus macaque (Macaca mulatta) was acquired from a commercial breeder and placed in quarantine. Within 8 days of arrival, the animal became anorexic, inactive, and dehydrated. Subsequently, generalized edema and facial ecchymoses developed, and despite supportive therapy, the animal became moribund and was euthanatized. Macroscopic examination showed diffuse stippling and streaking of the myocardium. Histopathologic examination revealed multifocal to coalescing myocardial edema, necrosis, lymphohistiocytic inflammation, and generalized endothelial infection with Sarcocystis sp. Immature and mature schizonts within endothelial cells were most prevalent in the heart. Fewer schizonts were present in the vasculature of other tissues, including skeletal muscle, smooth muscle, adipose tissue, brain, and retina. Mature tissue cysts within muscle fibers were not found in the myocardium but were occasionally seen in skeletal muscle. Analysis of polymerase-chain-reaction-amplified 18s ribosomal RNA gene sequences revealed 96% identity to published sequences of S. hirsuta, S. hominis, and S. fusiformis and 95% identity to S. cruzi and S. tenella. However, sequences did not show complete identity with any organism in the GenBank database. Sequence homology suggests that this is a newly described Sarcocystis sp. Results of antibody tests for simian retrovirus, simian T-lymphotropic virus 1, and simian immunodeficiency virus were negative, suggesting that viral immunosuppression was unlikely to have augmented the pathogenicity of sarcosporidial infection. Clinical and histopathologic findings in this case of fulminant sarcosporidiosis are similar to those described in Dalmeny disease in cattle, which is associated with ingestion of massive numbers of infective Sarcocystis oocysts.

Acute Disease↗

PubMed1998

Effects of task goal on movement kinematics and line bisection performance in adults without disabilities.

OBJECTIVE: This study investigated (a) whether the kinematic profile of a reaching-for-an-object movement would differ depending on the goal of the reaching task and (b) the effect of task goal on attentional carryover. METHOD: Twenty-four adults without disabilities performed a horizontal line bisection task under three conditions: (a) a natural condition (pressing the ringing lever of a desk bell), (b) an impoverished condition (touching the ringing lever of a desk bell), and (c) a control condition (bisecting a line only). Only the natural and impoverished conditions used the reaching task (i.e., pressing or touching the ringing lever of the desk bell). The kinematic profile of reaching for the bell was established with the OPTO-TRAK system, a quantitative kinematic analysis measure. The line bisection task was performed immediately after the reaching task, which was located adjacent to the left of the line to be bisected. RESULTS: The natural condition elicited better quality of reaching movement than did the impoverished condition. It produced significantly shorter movement time and higher peak velocity. A less impressive effect was found for percentage of reach where peak velocity occurs. Bisection performance under the two experimental conditions was leftward biased relative to the control condition, and the magnitude of leftward bias in the natural condition was greater than that for the impoverished condition. CONCLUSION: Results supported one core assumption of occupational therapy: goal-directed and functional tasks can be used to enhance human performance. If the results hold for clinical populations, manipulations of functional goals may enhance movement performance of persons with disabilities and remediate left neglect often seen in clients who have had a stroke.

Adult↗

PubMed1998

Characterization of pulsatile secretion of gonadotropin and prolactin in women with normal menstrual cycle, secondary amenorrhea and polycystic ovary syndrome (PCOS).

To characterize the episodic fluctuations of serum LH, FSH and PRL in women with normally cycling, secondary amenorrhea and polycystic ovary syndrome (PCOS), four groups of women were studied: group I (N = 8) consisted of normal women in the follicular phase of the cycle; group II (N = 10) of women with secondary amenorrhea and positive progesterone withdrawal bleeding; group III (N = 8) of women with secondary amenorrhea and negative progesterone withdrawal bleeding; group IV (N = 9), women with polycystic ovary syndrome (PCOS). Blood samples were obtained at 15 minute intervals for 4 hours during one admission day. Ovarian steroids were measured to evaluate the baseline endocrine environment in each group. Distinct pulsatile fluctuations of serum LH, FSH and PRL were observed in all subjects. These pulses showed a high degree of coincidence in LH with FSH and LH with PRL in each group. However, the mean (+/- SD) frequencies of LH in group III and group IV were significantly lower (P < 0.01) and higher (P < 0.01) than in group I, respectively. The mean frequencies of FSH in groups III and IV were lower (P < 0.05), as compared with those of group I. The mean amplitude of LH in group IV was significantly higher (P < 0.001) than in group I. These results suggest that loss of the regulatory pulsatility of gonadotropin releases may be a contributory cause to anovulation and secondary amenorrhea. The concomitant pulsatile releases of gonadotropin and PRL are essential to reproductive function and their regulatory controls in the follicular phase may be mediated through a common neuroendocrine mechanism in normal and hypogonadal women.

Adult↗

PubMed1998

Assessment of hypothalamic-pituitary function by hormonal pulsatility, gonadotropin-releasing hormone and thyrotropin-releasing hormone testing in women with euprolactinemic secondary amenorrhea.

To evaluate the integrated hypothalamic-pituitary function of euprolactinemic secondary amenorrhea, blood samples of 23 patients were taken every 15 min for 4 hours in examination of pulsatile LH, FSH, PRL secretions and then 2 hours GnRH, TRH tests were performed. Nine normal cycling women (group I) served as the controls. Thirteen amenorrheic women (group II) revealed responsive bleeding to progestin injection and the other 10 women (group III) were nonresponsive. The LH frequency, amplitude, and LH response to GnRH of groups II and I were comparable, whereas delta PRL after TRH in group II (60.8 +/- 18.9 ng/ml) exhibited a significantly (P < 0.05) exaggerated response, as compared with that of group I (43.6 +/- 11.4 ng/ml). The LH frequency (1.3 +/- 0.4/4h) and amplitude (1.7 +/- 0.4 mIU/mL) of group III were significantly lower (P < 0.01) than those in group I (2.4 +/- 0.5 and 2.5 +/- 0.5, respectively), but their delta LH and delta FSH responses to GnRH showed no differences from those of controls. The frequency, amplitude of PRL and delta PRL response to TRH in group III were no significant difference with those of group I. These results suggest that masked PRL hypersecretion and loss of the regulatory pulsatility of gonadotropin release may be responsible in part for the causes resulting to euprolactinemic secondary amenorrhea. The analysis of these hormonal environments is useful for the understanding of clinical perspectives, pathophysiology and management.

Adult↗

PubMed1997

Random mutagenesis of the cAMP chemoattractant receptor, cAR1, of Dictyostelium. Mutant classes that cause discrete shifts in agonist affinity and lock the receptor in a novel activational intermediate.

The cAMP chemoattractant receptor, cAR1, of Dictyostelium transduces extracellular cAMP signals via G protein-dependent and G protein-independent mechanisms. While site-directed mutagenesis studies of G protein-coupled receptors have provided a host of information regarding the domains essential for various functions, many mechanistic and structural questions remain to be resolved. We therefore carried out polymerase chain reaction-mediated random mutagenesis over a large part of the cAR1 sequence (from TMIII through the proximal part of the cytoplasmic tail). We devised a rapid screen for loss-of-function mutations based on the essential role of cAR1 in the developmental program of Dictyostelium. Although there were an average of two amino acid substitutions per receptor, approximately 90% of the mutants were able to substitute for wild-type cAR1 when expressed in receptor null cells. About 2% were loss-of-function mutants that expressed wild-type levels of receptor protein. We used biochemical screens to select about 100 of these mutants and chose eight representative mutants for extensive characterization. These fell into distinct classes. One class had a conditional defect in cAMP binding that was reversed by high salt. Another large class had decreased affinity under all conditions. Curiously, the decreases were clustered into three discrete intervals. One of the most interesting class of mutants lost all capacity for signal transduction but was phosphorylated in response to agonist binding. This latter finding suggests that there are at least two activated states of cAR1 that can be recognized by different downstream effectors.

Animals↗

PubMed1996

Effects of left-sided movements on line bisection in unilateral neglect.

Thirteen patients with left neglect performed line bisection under four conditions: no cue, visual cueing involving the report of a digit placed at the left end of the line, circling the left-end digit, and digit circling plus tracing of the line with the right index finger from its left end to its midpoint before bisection. Digit circling plus finger tracing was unequivocally more effective in reducing left neglect than digit circling alone, which was in turn more effective than visual cueing; indeed, digit circling with tracing completely abolished the rightward bisection bias. Thus continuously directing visuomotor control to the left side of the line (even with the right hand) until bisection is performed reduces neglect more than only requiring patients to attend to left-sided visual cues. The facilitatory effects of the cueing procedures may reflect their differential efficacy in constraining as well as attracting attention and action to the left part of the target line. These findings have implications for neglect rehabilitation.

Adult↗

PubMed1996

Isolation and expression of a host response gene family encoding thaumatin-like proteins in incompatible oat-stem rust fungus interactions.

Four cDNA clones (corresponding to tlp-1, -2, -3, and -4 genes) encoding thaumatin-like (TL), pathogenesis-related proteins were isolated from oat (Avena sativa) infected by an incompatible isolate Pga-1H of the oat stem rust fungus (Puccinia graminis f. sp. avenae). All four cDNA clones contained an open reading frame predicted to encode a 169-amino acid polypeptide with a signal peptide of 21 amino acids at the N-terminus, suggesting that these proteins are transported through a secretory pathway. The amino acid sequences revealed high homology among the four cDNA clones, 80 to 99% identity and 86 to 100% similarity. The tlp genes and several TL protein genes of certain cereals are clustered into a small group that is phylogenetically separate from the major group of TL protein genes of several plant species. In plants infected with the incompatible isolate Pga-1H, or an inappropriate isolate Pgt-8D of P. graminis f. sp. tritici, high levels of tlp gene transcripts accumulated at 42 to 48 h AI and thereafter when hypersensitive host cell death occurred and hyphal growth was inhibited, whereas in plants infected with a compatible isolate Pga-6A, relatively lower amounts of transcripts were detected. Overall, transcript levels were higher with tlp-1 than with the three other genes. Spray with a light mineral oil used as a spore carrier induced transient expression of tlp-1, -2, and -3 genes at 16 to 30 h AI which obscured the initial induction of the tlp genes in response to infection by the pathogens. In contrast, tlp-4 was induced very little by oil spray, so that induction was clearly observed in response to either compatible, incompatible, or inappropriate isolates at 24 to 30 h AI. Wounding leaves by either slicing or puncturing them strongly induced tlp-1 and tlp-3, moderately induced tlp-2, but had no effect on tlp-4. Taken together, the results showed that tlp genes displayed differential responses to oil spray, mechanical wounding, and pathogen infection and that the expression of tlp genes, especially tlp-1, in oat is associated with resistance reactions in response to infection by incompatible and inappropriate isolates of the stem rust fungi.

Amino Acid Sequence↗

PubMed1996

Ultrasound-guided percutaneous transhepatic fine needle aspiration cytology study of gallbladder polypoid lesions.

OBJECTIVE: To determine the accuracy and safety of ultrasound (US)-guided percutaneous transhepatic fine needle aspiration cytology (PT FNAC) in the diagnosis of large gallbladder (GB) polyps, especially cholesterol polyps. METHODS: Between January 1993 and April 1995, 17 patients with GB polyps of a size over 1 cm were examined preoperatively with US-guided PT FNAC, with needle aspiration from the center of the polyps. A cytological-histopathological correlation study was performed postoperatively to assess the accuracy of the PT FNAC results. RESULTS: 1) All eight cholesterol polyps were accurately diagnosed with the PT FNAC alone, showing foamy histiocytes. 2) In five patients, a diagnosis of epithelial tumor was made with PT FNAC study, showing the presence of columnar epithelium, but the PT FNAC failed to detect focal malignant change in adenomas of three of these patients. Only one case of adenocarcinoma was correctly diagnosed preoperatively by the PT FNAC. 3) The PT FNAC failed to detect an inflammatory polyp in one patient. 4) Failed cytology study was encountered in three patients-only bile was aspirated out. One patient had a GB stone, misdiagnosed as a GB polyp, another had an adenomyoma, and the last patient had chronic cholecystitis with Rokitansky-Aschoff sinuses. 5) One complication occurred-mild bile peritonitis. CONCLUSIONS: US-guided PT FNAC directly targeting the GB lesions seems accurate in the diagnosis of cholesterol polyps, and is a safe procedure.

Adenocarcinoma↗

PubMed1996

[Operation directions by comparing financial ratio of 22 provincial hospitals].

Even more restrictive regulations and reimbursement limits seem to be a very heavy burden and stress for most provincial hospitals, especially after the National Health Insurance System has been introduced. The purpose of this project to find a better, universal direction for these hospitals through three steps: 1) Using different financial and accounting ratio indexes to evaluate the general business performance of each hospital. 2) Taking a comprehensive questionnaire with senior managers of each hospital to know their concepts and attitudes concerning external environment and internal operation. 3) Comparing data's correlation and differentiation to ascertain better trends for future operation for all hospitals. The database for this project comes from two resources: 1) Government finance and budget reports of 22 provincial hospitals for the 1994 accounting calendar year. 2) The results of questionnaires returned by 274 senior managers of hospitals, and analysis of these by chi-square test. Through statistical comparison, a number of conclusions can be made: 1) Most hospitals have better operation efficiency if any professional hospital administrator is working for them. 2) The hospital with more comprehensive personnel system shows better business performance. 3) The hospital with routine and formal financial analysis reports always has better business performance. 4) The hospital with poor operational efficiency tends to get rid of restriction or limitation from government's system. 5) The hospital with good operational efficiency has more confidence and desire to improve and change. 6) The hospital with poor operational efficiency is more dependent on outside support from government. 7) The hospital with better business performance has more concern about the impact of malpractice around the hospital. In short, a hospital with poor business efficiency always has more pessimistic attitude and tends to rely on outside resource support. On the other hand, a hospital with more confidence, flexibility and readiness for internal improvement always demonstrates greater business efficiency.

Economics, Hospital↗

PubMed1995

A simple method for DNaseI footprinting analysis.

DNaseI footprinting technique has been a very useful method in gaining direct and immediate information about the location of a protein binding site in the DNA sequence. In this report, we present a method that overcomes many of the inconveniences of previous methods. This method was based on the combination of PCR technique and the dideoxy DNA sequencing reaction. It avoids the need of the secondary restriction sites that any candidate DNA sequence for DNaseI footprinting analysis can be prepared efficiently as long as its flanking sequences are known. Replacing the difficult Maxam-Gilbert DNA sequencing with the dideoxy-mediated DNA sequencing method makes the footprinting experiments even safer and easier.

Base Sequence↗

PubMed1995

Collagenolytic enzymes and progestin in induced ovulation in rabbits with hyperprolactinemia.

To clarify the possible role of collagenolytic enzymes and progestin in induced ovulation and to investigate whether progesterone interacts with these enzymes in leading to ovulation during the hyperprolactinemic state, the alterations of 2,4-dinitrophenyl-Pro-Gln-Gly-Ile- Ala Gly-Gln-D-Arg-OH peptidase (DNP-peptidase) and alpha-n-benzoyldl-Arg-beta-naphthylamide hydrolase (BANA-hydrolase) activities were measured in rabbit ovaries. The ovaries were primed with four daily sulpiride (SLP) injections followed by human chorionic gonadotropin (hCG) administration. The peripheral and ovarian progesterone, 20 alpha-hydroxypregn-4-en-3-one (20 alpha OHP) levels and ovulation rate at 14 hours after hCG administration in SLP-treated rabbits were significantly suppressed as compared with the control animals. The usual changes in DNP-peptidase and BANA-hydrolase activities in the follicular tissue at 8 and 10 hours after hCG were also altered by this abnormal hypersecretion of circulating prolactin. When progesterone was administered concomitantly with hCG to the hyperprolactinemic rabbits during ovulation induction, the ovulation rate was restored to a physiologic level comparable to that of the controls. These results suggest that both progesterone and collagenolytic enzymes are mandatory for follicular rupture induced by hCG and that progesterone may interact with these enzymes to facilitate the completion of the ovulatory process during the hyperprolactinemic state.

Animals↗

PubMed1994

Transcriptional analysis of the Escherichia coli bio operon.

Using primer extension, two in vivo transcription start points (tsp) were identified for rightward transcription of the Escherichia coli biotin operon, at nucleotides (nt) +20 and +29. The strongest leftward transcript begins at +9, with a tenfold less abundant transcript starting at +3. The activity of segments cloned into promoter probe vectors locates the major leftward promoter between nt +1 and +105, as expected for the +9 tsp. Although the activity of a chromosomal operator is reduced about 300-fold by point mutation in either arm of the palindrome extending from nt -20 to +20, either a half-operator segment or a full operator bearing the same point mutation in one arm is substantially repressed when cloned into pKB2000, as though cellular location strongly affects the operator's affinity for the repressor.

Base Sequence↗

PubMed1994

A comparison of enzyme-linked immunosorbent assay (ELISA) with sperm immobilization test (SIT) in detection of antisperm antibodies in sera of infertile women.

In the present study, an enzyme-linked immunosorbent assay (ELISA) for antisperm antibodies was compared with a traditional standard sperm immobilization test (SIT) in sera from 158 infertile women in order to evaluate their clinical usefulness for various causes of infertility. Ten pregnant and unmarried women were used as the control group. There was a higher incidence rate by ELISA (13.9%) compared with that by SIT (10.1%) after examination of overall samples, although the difference was not statistically significant. The unexplained infertility group exhibited the highest incidence among the various causes of infertility in both of these two methods. Fifteen (93.8%) of 16 patients with positive SIT showed positive reaction in ELISA method, indicating that a close correlation exists between the two methods. The positive predictive value (54.5%) of ELISA was significantly (p < 0.05) lower than that (87.5%) of SIT, as evaluated with the results of postcoital test (PCT) performed at periovulatory phase. This suggests that the ELISA method for antisperm antibodies is less specific than SIT in view of the PCT results. Nevertheless, no fresh sperms are not required for the ELISA examination. Thus, it seems that the ELISA method may provide a convenient and practical means for mass screening in detecting antisperm antibodies in clinical practice.

Agglutination Tests↗

PubMed1994

The relationship between occupational form and occupational performance: a kinematic perspective.

OBJECTIVES: This study examined, through kinematic analysis, the effect of occupational form on reaching performance. The hypothesis was that reaching performance would show an enhanced quality of movement in materials-based occupation (i.e., pick up a pencil and prepare to write one's own name) than in imagery-based occupation (i.e., pretend to pick up a pencil and prepare to sign one's own name) and in exercise (i.e., move the arm forward). It was further hypothesized that imagery-based occupation would elicit better performance than exercise. METHOD: The reaching performance was measured, using WATSMART (Waterloo Spatial Motion Analysis & Recording Technique), by the variables including reaction time, movement time, number of movement units, total displacement, the amplitude of peak velocity, and percentage of reach in which peak velocity occurred. A repeated-measures counterbalanced research design was used with 37 female college students. Contrast analysis was used to test the hypotheses. RESULTS: Materials-based occupation elicited enhanced quality of movement performance, as compared with imagery-based occupation and exercise. However, exercise seemed to elicit better performance than imagery-based occupation. CONCLUSION: The practical implication is that materials-based occupation might be used to elicit enhanced quality of reaching movement in occupational therapy intervention.

Adolescent↗

PubMed1994

Evidence of progesterone dependence in ovulation induced by human chorionic gonadotropin in female rabbits.

The ovulation rate at 14 hours after human chorionic gonadotropin (hCG) injection in female rabbits was significantly reduced and the postovulatory increase in progesterone levels in peripheral and ovarian veins were suppressed by four days sulpiride-induced hyperprolactinemia, as compared to the control group. However, the levels of estradiol and testosterone from the same samples showed comparable alterations between the control and sulpiride-treated rabbits. When progesterone was added to hCG to induce ovulation in sulpiride-primed animals, the ovulation rate was restored as compared to the control group. These results suggest that progesterone is a prerequisite for ovulation in this experimental system.

Animals↗

PubMed1994

Effects of long-acting propranolol and verapamil on blood pressure, platelet function, metabolic and rheological properties in hypertension.

The newly developed antihypertensive drugs, the long-acting beta-blocker propranolol and the sustained release calcium antagonist verapamil, are compared in their antihypertensive, platelet function, rheological properties and metabolic effects. The trial was a double-blind, randomised, placebo-controlled cross-over study. Thirty patients with mild to moderate hypertension received propranolol (40-120 mg) or verapamil (80-200 mg) once daily in two separate ten week courses. After ten weeks treatment both drugs had significantly reduced both SBP and DBP. Beta-thromboglobulin (beta-TG) concentration, reflecting the status of platelet activation in vivo, was significantly decreased after propranolol (129.6 +/- 13.5 vs. 77.9 +/- 8.6 ng/ml) and verapamil (129.6 +/- 13.5 vs. 90.7 +/- 10.1 ng/ml) treatments while platelet aggregation induced by ADP, collagen, arachidonic acid or adrenaline and the production of thromboxane B2 (TXB2), 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) and platelet cyclic 3'-5' adenosine monophosphate (C-AMP) concentration were not affected. Significant alterations in rheological parameters such as plasma and whole blood viscosity, fibrinogen level and red cell deformability were not found. Higher cholesterol and low-density lipoprotein-cholesterol (LDL-C) levels were observed after propranolol treatment but not in verapamil treatment. Side-effects were mild, tolerated and no patient had to be withdrawn from the study. In conclusion, propranolol and verapamil are generally effective antihypertensive as well as rheologically safe drugs. Compared with the metabolic effect on serum lipid, verapamil may be a better choice. Both drugs possess the tendency to inhibit platelet properties which is desirable in hypertension treatment.

Adult↗

PubMed1994

Relationship between pituitary reserve and efficacy of bromocriptine in women with euprolactinemic ovulatory dysfunction.

To evaluate the relationship between pituitary reserve and efficacy of bromocriptine therapy in patients with euprolactinemic ovulatory dysfunction, the responses of prolactin (PRL) to thyrotropin-releasing hormone (TRH) and luteinizing hormone (LH), follicle-stimulating hormone (FSH) to gonadotropin-releasing hormone (GnRH) provocation in 46 anovulatory patients were compared with 15 normally cycling ovulatory women. After provocation, the patients were treated with bromocriptine 2.5 mg twice a day for two weeks from the day of menstruation or withdrawal bleeding. Within 12 weeks, 29 of 46 (63.0%) patients had resumption of ovulatory menstruation, and 11 of them became pregnant. There were a significantly (P < 0.001) exaggerated responses of PRL to TRH in bromocriptine responders compared to controls and nonresponders. Also, LH responses to GnRH were higher in responders than in controls and nonresponders, although there was no significant differences. However, FSH responses to GnRH were significantly (P < 0.005) lower in bromocriptine nonresponders, as compared with the controls and responders. These results demonstrate that pituitary reserve of PRL and gonadotropin may correlate with the efficacy of bromocriptine and aid to predict the outcome of therapy in patients with euprolactinemic ovulatory dysfunction.

Adult↗