Biomedical subjects

K Liu

Publications and source records attributed to K Liu.

At least 163 records · Page 9Linked to original sources

PubMed1999

Diagnosis of posttransplant granulocytic sarcoma by fine-needle aspiration cytology and flow cytometry.

We describe a patient who developed granulocytic sarcomas of the mesentery and breast approximately 4 yrs following an allogenic bone marrow transplantation for acute myeloblastic leukemia. The diagnosis was made by a combination of fine-needle aspiration cytology and flow cytometry. The differential diagnoses of localized masses in posttransplant patients and how the combination of fine-needle aspiration cytology and flow cytometry may be used are discussed.

Adult↗

PubMed1999

Logistic regression analysis of small round cell neoplasms: a cytologic study.

The diagnosis of small round cell neoplasms (SRCN) in children is difficult by both histologic and cytologic methods. These neoplasms are unified morphologically by the scanty cytoplasm surrounding relatively round nuclei containing a primitive chromatin pattern. Further categorization is achieved histologically by the recognition of architectural differentiation and cytoplasmic features. Numerous series and case reports documenting the cytologic features of SRCN have been published in the English-language literature, but relatively few studies have statistically analyzed the diagnostic utility of these features. Our logistic regression analysis of 59 cases of SRCN indicates that the presence of an extremely scanty cytoplasm favors the diagnosis of Ewing's sarcoma (P = 0.004), as does the positive expression of cytoplasmic vacuoles (P = 0.02). Strap or tadpole cells closely correlate with the diagnosis of rhabdomyosarcoma (P < 0.001). The positive expression of rosettes strongly supports the presence of a neuroblastoma (P < 0.001). The diagnosis of Wilms' tumor is confirmed by the expression of tubules (P < 0.001). The presence of lymphoglandular bodies strongly favors the diagnosis of lymphoma (P < 0.001). While some cytologic features are highly correlated with specific SRCN, these features are not invariably present, and definitive diagnosis may require immunohistochemical or ultrastructural analysis performed on cell block material.

Carcinoma, Small Cell↗

PubMed1999

Fine-needle aspiration findings in idiopathic retroperitoneal fibrosis.

Idiopathic retroperitoneal fibrosis (IRF) is an inflammatory and fibrosing process that can be complicated by periureteral encasement, ureteral obstruction, and subsequent renal failure if left untreated. Unfortunately, treatment is often delayed due to the nonspecific nature of the presenting signs and symptoms. Clinical, radiologic, and microscopic findings in IRF, if examined independently, are all nonspecific for its diagnosis. Rendering a diagnosis of IRF by fine-needle aspiration (FNA) requires supportive clinical and radiologic data and systematic evaluation of entities in the differential diagnosis. Herein we report 2 cases of IRF diagnosed by FNA with subsequent histologic confirmation. Smears prepared from the aspirates revealed a combination of inflammatory cells and fibrous tissue. The inflammatory component was comprised of a mixture of lymphocytes, plasma cells, and rare eosinophils and mast cells. These 2 cases represent, to our knowledge, only the second report of IRF diagnosed by FNA.

Aged↗

PubMed1999

Fine-needle aspiration with flow cytometric immunophenotyping for primary diagnosis of intra-abdominal lymphomas.

Cytomorphology in conjunction with immunophenotypic characterization is becoming increasingly used for the primary diagnosis of non-Hodgkin's lymphomas (NHL). This combination is especially advantageous for the diagnosis of intra-abdominal and intrathoracic lymphomas, since unlike superficial lesions, open biopsy of deep-seated tissues is more invasive and more costly, and is associated with a higher risk. We report the cytologic and immunophenotypic features of intra-abdominal NHL obtained by fine-needle aspiration (FNA). Twenty-two cases of intra-abdominal lesions obtained by image-guided FNA where flow cytometry was also performed were reviewed. Of the 22 studied cases, 7 were classified as large-cell lymphoma, 5 as follicular center-cell lymphoma, 2 as small noncleaved-cell lymphoma, 2 as lymphoplasmacytoid lymphoma, one as small lymphocytic lymphoma, and one as marginal-zone lymphoma. In the remaining 4 cases where the immunophenotypic pattern was not definitive, the cytomorphologic features were of small cleaved cells in 3 cases and of mixed small cleaved and large cells in one case. We successfully classified 9 of the 10 patients on whom histologic confirmation was obtained. The successful primary classification of most intra-abdominal non-Hodgkin's lymphomas can be done with a combination of cytology and flow cytometry, and this can be the initial approach in patients with deep-seated lesions. Diagn. Cytopathol. 1999;21:98-104.

Abdominal Neoplasms↗

PubMed1999

Diagnosis of anaplastic large-cell lymphoma, including multifocal osseous KI-1 lymphoma, by fine-needle aspiration biopsy.

We present the fine-needle aspiration (FNA) findings of 4 cases of anaplastic (Ki-1) large-cell lymphoma (ALCL). A primary diagnosis of ALCL was made on FNA material in 2 cases, of which one was a multifocal osseous Ki-1 lymphoma. In the other 2 patients who had a known history of ALCL, FNA was used to detect recurrent disease. In all cases, large discohesive pleomorphic cells in the absence of lymphoglandular bodies in the background raised the possibility of a nonhematopoietic neoplasm. Immunochemical staining for CD30 was positive in all cases. The cytomorphologic and immunochemical features are discussed, along with the differential diagnosis of Ki-1 lymphoma. Diagn. Cytopathol. 1999;21:174-179.

Adolescent↗

PubMed1999

Radiologically-determined diameter, pathologic diameter, and reactive zone surrounding pulmonary neoplasms: implications for transthoracic fine-needle aspiration of pulmonary neoplasms.

To determine the relationship between radiologically determined tumor diameter and true pathologic tumor diameter and correlate radiologically determined diameter with the size of reactive zone surrounding pulmonary neoplasms, radiographs and surgical pathology specimens were obtained from 57 patients with pulmonary neoplasms. The tumor size on plane films and CT-scans was measured, as was the size of the neoplasm on gross specimen and surgical pathology slide. The width of the reactive zone was also measured on H&E stained microscopic slides. These findings were correlated along the histopathologic type of neoplasm present. On average, the reactive zone represented approximately 11% of the overall diameter of the neoplasm. However, there was considerable variation in this percentage, with reactive zone thickness varying between 2% and 48% of total tumor diameter. Bronchioloalveolar cell carcinomas generally lacked a reactive zone, while the other types of carcinomas frequently contained reactive zone. Approximately half of all carcinomas displayed a reactive zone of 1 mm in thickness or more. The present study demonstrates that a majority of carcinomas contain a reactive zone. This reactive zone is of variable thickness, but in approximately 50% of carcinomas it is at least 1 mm in thickness. The thickness of the reactive zone represents approximately 11% of total tumor diameter. Diagn. Cytopathol. 1999;21:250-252.

Biopsy, Needle↗

PubMed1999

Intermittent pneumatic compression of legs increases microcirculation in distant skeletal muscle.

Intermittent pneumatic compression has been established as a method of clinically preventing deep vein thrombosis, but the mechanism has not been documented. This study observed the effects of intermittent pneumatic compression of legs on the microcirculation of distant skeletal muscle. The cremaster muscles of 80 male rats were exposed, a specially designed intermittent pneumatic-compression device was applied to both legs for 60 minutes, and the microcirculation of the muscles was assessed by measurement of the vessel diameter in three categories (10-20, 21-40, and 41-70 microm) for 120 minutes. The results showed significant vasodilation in arterial and venous vessels during the application of intermittent pneumatic compression, which disappeared after termination of the compression. The vasodilation reached a maximum 30 minutes after initiation of the compression and could be completely blocked by an inhibitor of nitric oxide synthase, NG-monomethyl-L-arginine (10 micromol/min). A 120-minute infusion of NG-monomethyl-L-arginine, beginning coincident with 60 minutes of intermittent pneumatic compression, resulted in a significant decrease in arterial diameter that remained at almost the same level after termination of the compression. The magnitude of the decrease in diameter in the group treated with intermittent pneumatic compression and NG-monomethyl-L-arginine was comparable with that in the group treated with NG-monomethyl-L-arginine alone. The results imply that the production of nitric oxide is involved in the positive influence of intermittent pneumatic compression on circulation. It is postulated that the rapid increase in venous velocity induced by intermittent pneumatic compression produces strong shear stress on the vascular endothelium, which stimulates an increased release of nitric oxide and thereby causes systemic vasodilation.

Animals↗

PubMed1999

Motor functional and morphological findings following end-to-side neurorrhaphy in the rat model.

Nerve repair cannot always be achieved by the conventional end-to-end technique. This study evaluated the functional recovery of nerves repaired with end-to-side neurorrhaphy in a rat model. The right peroneal nerves of 80 female rats were transected and divided into four groups. In group A, the nerve ends were separated and remained unrepaired; in group B, the distal peroneal ends were directly sutured to the epineurium of the tibial nerves in end-to-side fashion; in group C, the distal ends were sutured through an epineurial window at the repair site in end-to-side fashion; and in group D, the nerve ends were reconnected by the traditional end-to-end technique. Evaluation included gait analysis by calculation of a peroneal functional index, measurement of contractile function of the extensor digitorum longus muscle, wet weight of the extensor digitorum longus, and histological examination. The findings of this study suggested the following: (a) end-to-side neurorrhaphy allows effective motor functional recovery, demonstrated by earlier improvement of the peroneal functional index, stronger muscle contractile function, greater muscle weight, and higher density of regenerated axons compared with unrepaired nerves; (b) removal of the epineurium of the donor nerve at the nerve coaptation site increases the effectiveness of end-to-side neurorrhaphy, but the epineurium appears to be a partial barrier to axonal regeneration; (c) removal of the epineurium does not affect the structure and function of the donor nerve; and (d) end-to-end repair achieved the best functional recovery among the four groups; therefore, end-to-side repair should be considered as a potential alternative only when no proximal nerve is available.

Animals↗

PubMed1999

Influences of inflation rate and duration on vasodilatory effect by intermittent pneumatic compression in distant skeletal muscle.

Previous study has demonstrated that application of intermittent pneumatic compression on legs can cause vasodilation in distant skeletal muscle at the microcirculation level. This study evaluated the influence of inflation rate and peak-pressure duration on the vasodilatory effects of intermittent pneumatic compression. The cremaster muscles of 50 male rats were exposed and divided into five groups of 10 each. A specially designed intermittent pneumatic-compression device was applied in a medial-lateral fashion to both legs of all rats for 60 minutes, with an inflation rate and peak-pressure duration of 0.5 and 5 seconds, respectively, in group A, 5 and 0 seconds in group B, 5 and 5 seconds in group C, 10 and 0 seconds in group D, and 10 and 5 seconds in group E. Diameters of arterial segments were measured in vessels of three size categories (10-20, 21-40, and 41-70 microm) for 120 minutes. The results showed that the greatest increase in diameter was produced by intermittent pneumatic compression with the shortest inflation rate (0.5 seconds). A moderate increase resulted from compression with an inflation rate of 5 seconds, and no effective vasodilation occurred during compression with the longest inflation rate (10 seconds). When the groups with different inflation rates but the same peak-pressure duration were compared, there was a significant difference between any two groups among groups A, C, and E and between groups B and D. When the groups with different peak-pressure durations but the same inflation rate were compared, compression with a peak-pressure duration of 5 seconds caused a generally similar degree of diameter change as did compression without inflation at peak pressure. The findings suggest that inflation rate plays an important role in the modulation of distant microcirculation induced by intermittent pneumatic compression whereas peak-pressure duration does not significantly influence the vasodilatory effects of the compression. This may be due to the fact that rapid inflation produces a significant increase in shear stress on the vascular wall, which stimulates vascular endothelium to release nitric oxide, causing systemic vasodilation.

Animals↗

PubMed1999

The effect of GHRH, GHRP-2 and somatostatin on GH secretion by fetal pituitary.

Growth hormone releasing peptide (GHRP-2) is a synthetic hexapeptide which specifically stimulates secretion of growth hormone (GH) by fetal pituitary somatotrophs through a new membrane receptor, which is different from growth hormone releasing hormone (GHRH) and somatostatin (SMS) receptors. We used cell cultures of human fetal pituitary somatotroph cells to investigate the effect of GHRH, GHRP-2 and somatostatin on GH secretion. The results showed that the mechanism of GHRH/SMS and GHRP-2 was different. This indicated that a different intracellular signal transduction system might also play a crucial role in the regulation of GH secretion.

Fetus↗

PubMed1999

Effects of the novel GH secretogogue, hexarelin on GH secretion and phosphatidylinositol hydrolysis by human pituitary somatotrophinomas in cell culture.

The effects of the novel GH-releasing hexapeptide, Hexarelin, on cultured human pituitary somatotrophinomas were investigated. Hexarelin (0.01-100 nmol/L) dose-dependently stimulated GH secretion up to 4.6-fold. Maximal effects occurred with 10 nmol/L. These effects were very similar to those observed with GHRP-6. The effects of Hexarelin were reduced by phloretin, an inhibitor of protein kinase C (PKC). The rate of phosphatidylinositol (PI) hydrolysis was markedly increased by Hexarelin in a dose-dependent manner. These results demonstrated that Hexarelin could directly stimulate GH secretion by human pituitary somatotrophs in a PKC-dependent manner, probably via activation of the PI transduction system.

Adenoma↗

PubMed1999

Intraoperative high dose fentanyl induces postoperative fentanyl tolerance.

PURPOSE: In a randomized, double-blind clinical trial, we compared the postoperative analgesic effect and dose consumption of fentanyl after intraoperative high dose and low dose fentanyl administration. METHODS: Sixty ASA class I to II female patients undergoing total abdominal hysterectomy (TAH), were randomly allocated to receive either 1 microg x kg(-1) (low dose group, n = 30) or 15 microg x kg(-1) (high dose group, n = 30) fentanyl during induction of anesthesia. Anesthesia depth was maintained with inhalation of halothane in the low dose group, or combined with 100 microg x hr(-1) fentanyl i.v. in the high dose group. Postoperative pain was treated with an intravenous patient-controlled analgesia system and was assessed with a visual analog pain score at rest. RESULTS: Patients in the high dose group had higher pain intensity at four and eight hours postoperatively, more fentanyl consumption and a greater incidence of emesis in the postoperative period of 16 hr than those in the low dose group (P < 0.05). Heart rate, blood pressure, and respiratory rate were similar between the two groups. CONCLUSION: Our results suggest that acute fentanyl tolerance develops after administration of high dose fentanyl during surgery and, consequently, results in a higher postoperative pain intensity and greater fentanyl consumption.

Analgesics, Opioid↗

PubMed1999

Testicular catch-up growth after varicocele correction in adolescents.

We evaluated retrospectively the outcome of artery-sparing (AS) versus non-artery-sparing (NAS) laparoscopic varicocelectomy and measured any reversal of testicular growth. Twenty patients (13 left and 7 bilateral varicoceles) were evaluated after surgery. A total of 27 varicocelectomies (20 AS and 7 NAS) were performed. The indication for surgery was smaller testicular size on the affected side in all patients and discomfort/pain in 3. The mean age was 12.9 years (range 8-15 years) at surgery. The testicular volumes were determined clinically and by color Doppler sonography (US). The follow-up time was 6-48 months after surgery. There were 4 recurrences out of 27 varicocelectomies (15%), of which 1 has been reoperated. Testicular volumes were equal in both groups after surgery, indicating catch-up growth except in the cases with minor recurrences (2 AS and 2 NAS varicocelectomies). In 12 testes, dilated veins in the pampiniform plexus were revealed by US. No severe intraoperative complications occurred. Three patients had a hydrocele after surgery (11%). These data show that there is testicular catch-up growth after varicocelectomy, but some questions remain unanswered: (1) should the remaining dilated veins detected by Doppler US be tackled; and (2) is an AS operation worthwhile?

Adolescent↗

PubMed1999

Effects of laparoscopic vs laparotomy treatment of E. coli peritonitis on hemodynamic responses in a porcine model.

BACKGROUND: Laparoscopic surgery is being used now for increasingly diverse clinical applications, including diagnosis and treatment of appendicitis and bacterial peritonitis. However, some concerns and controversies exist regarding the effectiveness of laparoscopic irrigation of the abdominal cavity compared with that achieved during laparotomy. Of no less importance is concern that establishing a CO(2) pneumoperitoneum in patients with cardiopulmonary insufficiency or endotoxemic shock may compromise hemodynamic function. The objective of this randomized, controlled study was to determine the effects of laparoscopic versus laparotomy intervention on hemodynamic and outcome measurements using a porcine model of Escherichia coli peritonitis. METHODS: For this study, 24 specific pathogen-free Hanford pigs underwent surgical placement of carotid, Swan-Ganz, and peritoneal catheters. After a 24-h recovery period, one subset of pigs (n = 12) received a bolus infusion of 9 x 10(8) CFU/kg E. coli intraperitoneally (septic) and intravenous fluid resuscitation. The remaining 12 pigs were not challenged with E. coli (control). Twenty-four hours later, all 24 pigs underwent either laparoscopic or open peritoneal irrigation with saline, then were reevaluated 48 h after surgical intervention. Standard cardiopulmonary, hematologic, and bacteriologic assessments were obtained both perioperatively and 48 h after surgical intervention. RESULTS: Pigs given E. coli exhibited significantly elevated heart rates and core temperatures and decreased O(2) saturation during the initial 6 h. Within 24 h, these pigs exhibited respiratory alkalosis, altered blood leukocyte profiles, and E. coli-infected peritoneal fluid. Random blood samples from the septic pigs tested negative for E. coli. Mean pulmonary artery and capillary wedge pressures were lower (p < 0.05) in septic than in control pigs before and after surgical intervention. Septic pigs that underwent laparoscopy had significantly lower (p < 0.05) arterial pH and higher arterial pCO(2) levels than septic pigs after laparotomy. Other cardiopulmonary responses were similar irrespective of the surgical modality used. One of six septic pigs from each surgical group still had E. coli growth in its peritoneal fluid 48 h after surgical intervention. CONCLUSION: Laparoscopic intervention demonstrated effectiveness equal to that of laparotomy for treating acute E. coli peritonitis in pigs without septic shock.

Animals↗

PubMed1999

Static and pulsatile blood pressure correlates of left ventricular structure and function in black and white young adults: the CARDIA study.

OBJECTIVE: To determine the unbiased relative strength of the association of static (systolic and diastolic) and pulsatile (pulse pressure) blood pressure components with left ventricular mass and function. BACKGROUND: Blood pressure is correlated with left ventricular mass; however, the unbiased relative strength of static and pulsatile blood pressure components with left ventricular mass and function is unknown in young adults. METHODS: Cross-sectional analyses of 3918 young adult participants at 4 community-based CARDIA clinical centers during 1990 and 1991. RESULTS: Left ventricular mass positively correlated (P <.01) with systolic, diastolic, and pulse pressure in all ethnicity-sex groups except for diastolic blood pressure in white men (P =.19). The association rank ordered as systolic blood pressure > pulse pressure > diastolic blood pressure except in white men, in whom pulse pressure and systolic blood pressure reversed positions in this hierarchy. Systolic blood pressure was the third and fourth strongest independent correlate of left ventricular mass in men and women, respectively. Body mass index, followed by height, was the strongest correlate of left ventricular mass in both sexes. Left ventricular wall thickness/chamber radius ratio positively correlated with diastolic and systolic blood pressure (women only) (P <.05) but not with pulse pressure. In all groups, stroke volume positively correlated (P <.05) with pulse pressure but was unrelated to static blood pressure measures, except for systolic blood pressure in black men. Left ventricular mass and the ventricular wall thickness/chamber radius ratio were greater in blacks compared with whites. CONCLUSIONS: Although systolic blood pressure was consistently the strongest unbiased blood pressure correlate of left ventricular mass, this relation varied by ethnicity and sex. Pulse pressure correlated with favorable left ventricular function and geometry, suggesting an opposite meaning to the ominous prognosis of wide pulse pressure in hypertensive, older adults.

Adolescent↗

PubMed1999

Scanning time efficient slinky for non-contrast MRA at low field.

To eliminate slab boundary artifact (SBA) for non-contrast multi-slab three-dimensional time-of-flight magnetic resonance angiogram (3D TOF MRA), we have previously developed a novel technique, termed SLINKY (Sliding Interleaved kY) acquisition in which a thin slab continuously "walks" along the z-axis while data are acquired in an interleaved fashion along the kY-axis. It has been demonstrated in our earlier works that SLINKY can suppress the SBA without any assumption of blood flow behavior, such as velocity or direction. At the same time, SLINKY keeps the same SNR as conventional multiple overlapping thin slab acquisition (MOTSA). Yet, this method is sensitive to any phase error along the ky axis. In our earlier application of SLINKY, we used navigator echoes to measure and correct the phase errors along the kY axis. The cost of using navigator echo collection is an increase in the imaging time. We therefore propose an improved SLINKY technique which does not use navigator echo collection for correcting phase errors, reducing the imaging time while keeping the same suppression of slab boundary artifacts. The present study demonstrates that by using a specifically designed RF pulse, the navigator echo collection can be avoided without incurring any extra ghosting or SNR reduction in the reconstructed images.

Artifacts↗

PubMed1999

Genetic dissection of systemic lupus erythematosus.

Recent progress towards elucidating the genetic basis for susceptibility to systemic lupus erythematosus (SLE) has provided insights into the manner in which individual susceptibility genes contribute to disease pathogenesis. Studies in animal models of systemic autoimmunity suggest that genes in three separate pathways contribute to the initiation and progression of systemic autoimmunity. Linkage studies in humans suggest that at least some susceptibility genes mediating disease in lupus-prone mice may also contribute to susceptibility in humans.

Animals↗

PubMed1999

The role of hydroxyl radical as a messenger in the activation of nuclear transcription factor NF-kappaB.

Although it is generally believed that reactive oxygen species activate NF-kappaB, a primary oxidative stress-responsive transcription factor, it is unclear which one among these species causes NF-kappaB activation. Our hypothesis is that hydroxyl radical (*OH) functions as a messenger for the activation of NF-kappaB. Jurkat cells, macrophages and JB6 cells were used to test this hypothesis. Cr(VI), silica and ZnO were used as sources of *OH radicals. None of these *OH generating systems involves exogenous H2O2. Cr(VI) expressed enhanced activity in induction of NF-kappaB in Jurkat cells. This activation of NF-kappaB was decreased by a metal chelator, diethylene triaminepentaacetic acid or a H2O2 scavenger, catalase, but was increased by superoxide dismutase. Mn(II), which reacts with Cr(IV) to inhibit this metal ion-mediated *OH generation, decreased the NF-kappaB activation. Sodium formate, an *OH radical scavenger, also inhibited the NF-kappaB activation. Electron spin resonance measurements show that Cr(VI) was reduced by Jurket cells to Cr(IV) and Cr(V). During the reduction process, molecular oxygen was reduced to O2 and then to H2O2, which reacted with Cr(IV) and Cr(V) to generate *OH radical. The *OH generation correlated with the Cr(VI)-induced NF-kappaB activation. Similarly, silica caused NF-kappaB activation in macrophages via the *OH radical-mediated reaction. This radical was generated via metal mediated reaction from H2O2, which was generated by the reduction of molecular oxygen via O2- as an intermediate during the silica-stimulated 'respirable burst'. Silica particles did not cause *OH generation either in Jurket or in JB6 cells and thus did not cause any observable NF-kappaB activation in these cells. ZnO induced NF-kappaB activation in JB6 cells through the generation of *OH resulting from light irradiation of ZnO which was measured by electron spin resonance. The results thus show that *OH radical functions as a messenger for NF-kappaB activation. Antioxidants, which scavenge *OH radical or its precursors, inhibit NF-kappaB activation. Metal chelators, which make metal ions incapable of generating *OH from H2O2, inhibit activation of this transcription factor.

Animals↗