Convulsions during superior laryngeal nerve block--a case report

Complications following local anesthesia for fiberoscope-assisted intubation are rare. We report a case with surgical condition indicating awake endotracheal intubation for general anesthesia, suffering from convulsions after receiving left superior laryngeal nerve block to facilitate the procedure. The possible cause may be accidental injection of the local anesthetic into the vertebral artery. Although the amount of local anesthetic injected was small, its concentration in the brain might be high enough to cause convulsion. The central nervous system toxicity of local anesthetic depends not only on the dosage used, but also on the rate of injection, as well as the site at which it is injected. Starting from a small dose together with careful monitoring of patient's response is advised when nerve block in the neck is performed. Here, we also emphasize the importance of availability of resuscitation equipment for maintaining adequate ventilation and circulation in case of emergency.

Polymorphism in the transmembrane region of the MICA gene and type 1 diabetes

Although MHC class II genes have a stronger association with type 1 diabetes than MHC class I genes, studies have shown that MHC class I molecules play an independent role in the etiology of type 1 diabetes, and the existence of susceptibility genes within a segment of MHC between the HLA-B and TNF genes has been predicted, where MHC class I chain-related gene A (MICA) resides. MICA has a triplet repeat polymorphism in the transmembrane region consisting of five alleles. We analyzed this polymorphism in 162 unrelated children (82 boys) with type 1 diabetes (age at diagnosis 7.01 +/- 3.76 yr) and 154 randomly selected unrelated children (87 boys), age 2.81 +/- 2.12 yr. Phenotype frequency of allele A9 in children with type 1 diabetes was significantly higher than in controls (RR = 2.42, 95% CI = 1.52-3.85, p = 0.000162, pc = 0.00081). Gene frequency of allele A9 was also significantly higher in children with type 1 diabetes when compared with control children (RR = 2.73, 95% CI = 1.85-4.03, p = 2.62 x 10(-7), pc = 1.31 x 10(-6)). This study demonstrates that MICA allele A9 confers risk of type 1 diabetes.

Decreased GTPase activity of K-ras mutants deriving from human functional adrenocortical tumours

Our previous studies have shown that seven out of 15 patients with adrenocortical tumours contained K-ras gene mutation. In addition, the mutation type was a multiple-site mutation, and the hot spots were located at codons 15, 16, 18 and 31, which were different from those reported before (codons 12, 13 and 61). To understand whether the mutation hot spots in human adrenocortical tumours were associated with activation of K-Ras oncogene and the alterations of its biocharacteristics, mutant K-Ras genes were cloned from tumour tissues and then constructed with expression vector pBKCMV. Mutant K-Ras genes were expressed at high levels in Escherichia coli and the resultant K-Ras proteins were shown to be functional with respect to their well-known specific, high-affinity, GDP/GTP binding. The purified K-Ras protein from E. coli were then measured for their intrinsic GTPase activity and the GTPase activity in the presence of GTPase-activating protein for Ras. The results showed that the wild-type cellular K-Ras protein (p21BN) exhibits about ten times higher intrinsic GTPase activity than the activated protein (p21BM3) encoded by mutant K-Ras gene, which mutated at codon 60. With regards to the codon 15, 16, 18 and 31 mutant K-Ras proteins (p21BM2), the GTPase activity in the presence of GAP is much lower than that of the normal K-Ras protein, whereas the intrinsic GTPase activity is nearly the same as that of the normal K-Ras protein. These results indicated that mutations at these hot spots of K-Ras gene were indeed activated K-Ras oncogene in adrenocortical tumours; however, their association with tumors needs further experiments to prove.

Treatment of recurrent Kaposi's sarcoma of an AIDS patient with weekly paclitaxel

Paclitaxel was recently recognized as an active chemotherapeutic agent for acquired immunodeficiency syndrome (AIDS)-associated Kaposi's sarcoma (KS). However, the best way to administer paclitaxel in AIDS-KS patients remains unknown. Herein, we reported an AIDS-associated KS patient whose disease progressed on the first-line chemotherapy with doxorubicin and bleomycin, but later responded well to weekly 1-hour infusion of 70 mg/m2 paclitaxel. It is particular noteworthy that this weekly dosing schedule resulted in almost negligible toxicities. The authors suggested a prospective study of weekly paclitaxel for AIDS-KS should be started as soon as possible.

Comparison of hemocytometer leukocyte counts and standard urinalyses for predicting urinary tract infections in febrile infants

OBJECTIVES

To compare the accuracy of standard and hemocytometer white blood cell (WBC) counts and urinalyses for predicting urinary tract infection (UTI) in febrile infants.

METHODS

Enrolled were 230 febrile infants < 12 months of age. All urine specimens were obtained by suprapubic bladder aspiration and microscopically analyzed by the standard urinalysis (UA) and by hemocytometer WBC counts simultaneously, and quantitative urine cultures were performed. Receiver-operating characteristic (ROC) curves were constructed for each method of UA. The optimal cutoff point of the UA test in predicting UTI was determined by ROC analysis.

RESULTS

There were 37 positive urine cultures of at least 1,000 CFU/ml. Of these 37 patients, 9 females and 28 males, 1 had a positive blood culture (Escherichia coli). Thirty (81%) of the positive urine cultures had a bacterial colony count > or = 100,000 colony-forming units/ml, whereas the remaining had between 1,000 and 50,000 colony-forming units/ml. The area under the ROC curve for standard UA was 0.790 +/- 0.053, compared with 0.900 +/- 0.039 for hemocytometer WBC counts (P < 0.05). For hemocytometer WBC counts, the presence of < or =10 WBC/microl appeared to be the most useful cutoff point, yielding a high sensitivity (83.8%) and specificity (89.6%). Standard UA, with a cutoff point of 5 WBC/high power field, had a lower sensitivity (64.9%) and similar specificity (88.1%). The hemocytometer WBC counts showed significantly greater sensitivity and positive predictive value (83.8 and 60.8%, respectively) than the standard urinalysis (64.9 and 51.1%, respectively) (P < 0.05). The accuracy, specificity and likelihood ratio of hemocytometer WBC counts were also greater than that of standard UA (88.7, 89.6 and 8.08% vs. 84.3, 88.1 and 5.44%).

CONCLUSION

Hemocytometer WBC counts provide more valid and precise prediction of UTI in febrile infants than standard UA. The presence of > or =10 WBC/microl in suprapubic aspiration specimens is the optimum cutoff value for identifying febrile infants for whom urine culture is warranted.

Urinary tract infection in febrile infants younger than eight weeks of Age

OBJECTIVE

To assess the usefulness of laboratory parameters, including peripheral white blood cell (WBC) count, C-reactive protein (CRP) concentration, erythrocyte sedimentation rate (ESR), and microscopic urinalysis (UA), for identifying febrile infants younger than 8 weeks of age at risk for urinary tract infection (UTI), and comparison of standard UA and hemocytometer WBC counts for predicting the presence of UTI.

METHODS

A total of 162 febrile children <8 weeks of age were enrolled in this prospective study. All underwent clinical evaluation and laboratory investigation, including WBC count and differential; ESR; CRP; blood culture; a lumbar puncture for cell count and differential, glucose level, protein level, Gram stain, and culture; and a UA and urine culture. All urine specimens were obtained by suprapubic aspiration and microscopically analyzed with standard UA as well as with hemocytometer WBC counts. Quantitative urine cultures were performed. Sensitivity, specificity, accuracy, likelihood ratios, and receiver operating characteristic (ROC) curves were determined for each of the screening tests.

RESULTS

There were 22 positive urine culture results of at least 100 colony-forming unit/mL. Eighteen of these 22 patients were males, and all were uncircumcised. There were significant differences for pyuria >/=5 WBCs/hpf, pyuria >/=10 WBC/microL, CRP >20 mg/L, and ESR >30 mm/hour between culture-positive and culture-negative groups (P <.05). The ROC area for hemocytometer WBC count, standard UA, peripheral WBC count, ESR, and CRP concentration were.909 +/-.045,.791 +/-.065,.544 +/-.074,. 787 +/-.060, and.822 +/-.036, respectively. The ROC curve analysis indicates that the CRP, ESR, and standard UA were powerful but imperfect tools with which to discriminate for UTI in potentially infected neonates. Hemocytometer WBC counts had the highest sensitivity, specificity, accuracy, and likelihood ratios for identifying very young infants with positive urine culture results. For all assessments, hemocytometer WBC counts were significantly different, compared with the standard urinalysis. ESR, CRP, and peripheral WBC counts were not helpful in identifying UTI in febrile infants.

CONCLUSION

UTI had a prevalence of 13.6% in febrile infants <8 weeks of age. The CRP, ESR, and standard UA were imperfect tools in discriminating for UTI, and the sensitivity of these laboratory parameters was relatively low. Hemocytometer WBC count was a significantly better predictor of UTI in febrile infants.

Association of CTLA4 gene A-G polymorphism with type 1 diabetes in Chinese children

OBJECTIVE

The CTLA4 (cytotoxic T lymphocyte associated antigen-4) gene encodes the T cell receptor involved in the control of T cell proliferation and mediates T cell apoptosis. Thus it is a strong candidate gene for T cell-mediated autoimmune disease. There is polymorphism at position 49 in exon 1 of the CTLA4 gene, providing a A-G exchange. This polymorphism is reportedly associated with type 1 diabetes in Caucasians but not in a small data set of Chinese. We wished to test this polymorphism in a larger and more homogeneous data set of Chinese children with type 1 diabetes and normal adult controls.

DESIGN

A population-based case-control study of a CTLA4 gene 49 A-G polymorphism was performed to look for an association with type 1 diabetes in Chinese children.

PATIENTS

We analysed this polymorphism in 253 unrelated children (128 boys) with type 1 diabetes (age at diagnosis 7.1 +/- 3.7 years) and 91 randomly selected normal adults. All individuals were Han Chinese.

RESULTS

The genotype and gene frequencies of children with type 1 diabetes differed significantly from those of adult controls (P = 0.0091 and P = 0.0051, respectively). Genotype CTLA4 49 G/G and G allele conferred a risk of type 1 diabetes (RR = 2.13, 95% CI = 1.31-3.46, P = 0.0022; RR = 1.68, 95% CI = 1.17-2.43, P = 0.0051, respectively).

CONCLUSIONS

This study demonstrates that CTLA4 49 A-G polymorphism is associated with type 1 diabetes in Han Chinese children. The CTLA4 49 G allele confers an increased risk of type 1 diabetes.

Curcumin-containing diet inhibits diethylnitrosamine-induced murine hepatocarcinogenesis

Curcumin has been widely used as a spice and coloring agent in foods. Recently, curcumin was found to possess chemopreventive effects against skin cancer, forestomach cancer, colon cancer and oral cancer in mice. Clinical trials of curcumin for prevention of human cancers are currently ongoing. In this study, we examine the chemopreventive effect of curcumin on murine hepatocarcinogenesis. C3H/HeN mice were injected i.p. with N-diethylnitrosamine (DEN) at the age of 5 weeks. The curcumin group started eating 0.2% curcumin-containing diet 4 days before DEN injection until death. The mice were then serially killed at the scheduled times to examine the development of hepatocellular carcinoma (HCC) and changes in intermediate biological markers. At the age of 42 weeks, the curcumin group, as compared with the control group (DEN alone), had an 81% reduction in multiplicity (0.5 versus 2.57) and a 62% reduction in incidence (38 versus 100%) of development of HCC. A series of intermediate biological markers were examined by western blot. While hepatic tissues obtained from the DEN-treated mice showed a remarkable increase in the levels of p21(ras), PCNA and CDC2 proteins, eating a curcumin-containing diet reversed the levels to normal values. These results indicate that curcumin effectively inhibits DEN-induced hepatocarcinogenesis in the mouse. The underlying mechanisms of the phenomenon and the feasibility of using curcumin in the chemoprevention of human HCC should be further explored.

The proneural gene amos promotes multiple dendritic neuron formation in the Drosophila peripheral nervous system

In the Drosophila peripheral nervous system, proneural genes direct the formation of different types of sensory organs. Here, we show that amos is a novel proneural gene that promotes multiple dendritic (MD) neuron formation. amos encodes a basic-helix-loop-helix (bHLH) protein of the Atonal family. During embryonic development, amos is expressed in patches of ectodermal cells, and the expression is quickly restricted to sensory organ precursors. Loss of amos function eliminates MD neurons that remain in ASC;atonal mutants. Misexpression of amos generates ectopic MD and other types of neurons. Amos interacts with the ubiquitously expressed Daughter-less protein in vivo and in vitro. Our final misexpression experiments suggest that a domain located outside the DNA-binding domain of Amos determines the MD neuronal specificity.

Neonatal vallecular cyst: report of eleven cases

BACKGROUND

Vallecular cyst is fairly uncommon in neonates and infants. Although benign in nature, it may cause severe airway obstruction and even death. This study retrospectively analyzed the clinical manifestations of vallecular cyst in neonates and discussed its management.

METHODS

From June 1993 through January 1997, 11 cases of vallecular cyst were collected and reviewed retrospectively. There were 8 male infants and 3 female infants. Their clinical manifestations, age at the onset of symptoms, age at diagnosis, and surgical management were analyzed. Fibrolaryngoscopy was used for preoperative diagnosis and postoperative follow-up.

RESULTS

The infants' initial presentations were inspiratory stridor, respiratory distress, noisy breathing, feeding difficulty, and failure to thrive. There was a high incidence of patients with coexisting signs of laryngomalacia (10/11). Ten patients received laryngomicrosurgery with CO2 laser for deroofing the cyst. Additional supraglottoplasty was performed at the same time in 4 patients with laryngomalacia type A + C and in one patient with severe laryngomalacia type C. Their symptoms all resolved soon after surgery. The phenomenon of laryngomalacia also disappeared. There has been no recurrence up to the present.

CONCLUSION

Although fairly uncommon, vallecular cyst should be included in the differential diagnosis of congenital laryngeal stridor in neonates. The use of fibroendoscopy can promptly diagnose vallecular cyst and any synchronous airway lesions. Although most of the synchronous laryngomalacia (type C) in this study was secondary to vallecular cyst, we suggest that supraglottoplasty be taken into consideration during cyst deroofing when the signs and symptoms of laryngomalacia type A are also present.

Concurrent chemoradiotherapy for locally advanced esophageal cancer--a pilot study by using daily low-dose cisplatin and continuous infusion of 5-fluorouracil

BACKGROUND

Concurrent chemoradiotherapy (CCRT) has recently become a promising treatment for esophageal cancer. However, most investigators have adopted the conventional or modified Wayne-State PF (cisplatin plus 5-fluorouracil) regimen, which is inevitably associated with moderate to severe treatment-related toxicities. In this pilot study, we incorporated a daily low-dose regimen of cisplatin and 5-fluorouracil into CCRT in order to improve the compliance of the patients.

PATIENTS AND METHODS

Between July 1993 and Dec. 1997, 25 patients with locally advanced esophageal cancer (T3, or N1 disease), received CCRT which consisted of daily low-dose cisplatin (6 mg/m2/day) and continuous infusion of 5-FU (225 mg/m2/day) with radiotherapy (fraction size = 200-250 cGy/day). Except for the initial 9 patients, for whom post-CCRT esophagectomy was compulsory, all subsequent patients underwent esophagectomy only when inadequate response to CCRT was noted. The scheduled radiation dose was 50 Gy for the first 9 patients, and 60 Gy for the rest of the patients.

RESULTS

Eighteen patients (72%) completed the CCRT without interruption. Clinically, there were 8 CR and 9 PR, with a total response rate of 68% (47-87%, 95% C.I.). All patients were evaluable for toxicity. Grade 3/4 leukopenia and thrombo-cytopenia developed in 14 (56%) and 7 (28%) patients, respectively. Grade 3/4 non-hematologic toxicity was seen in 4 (16%) patients. The median survival of the whole group was 8 months (range: 2-59+). The projected 3-year overall survival was 24%.

CONCLUSION

We suggest that for locally advanced esophageal cancer CCRT with the aforementioned daily low-dose regimen, is a treatment with good patient compliance.

Thyroid function in the sick very low-birth-weight infants

This study was undertaken to determine postnatal changes in thyroid function in very low-birth-weight (VLBW) infants. A total of one-hundred VLBW infants participated. Serial examination of serum levels of thyroxine (T4), free T4, triiodothyronine (T3), and thyroid-stimulating hormone (TSH) was performed in the neonatal period. A total of eighty-nine infants survived to discharge, while eleven died during hospitalization. Transient hypothyroxinemia was found in forty-one (46.1 percent) of the survivors. One of the surviving infants had primary hypothyroidism. His data was excluded from the analysis. In the other eighty-eight surviving infants, TSH levels were within normal limits throughout the six-week study period. T4 and free T4 values decreased after the first day of life, reaching a nadir at one week of age, followed by progressive increases. The mean cord blood T3 level was very low; the serum T3 value increased progressively in the postnatal period. We found a correlation between low T4 and free T4 values and mortality and neonatal illness. Hypothyroxinemia was associated with critical illness. In conclusion, the postnatal changes in thyroid function in VLBW infants were characteristic, with transient hypothyroxinemia being common in these infants. Further investigation of the relationship between thyroid function, death, neonatal illness, and developmental outcome is warranted.

Cardiovascular function in young patients with type 1 diabetes mellitus

Echocardiographic assessment of cardiovascular function was performed in 47 type 1 diabetic patients and 30 healthy control subjects of comparable age, height, weight, and heart rate. Indexed left ventricular mass, stroke volume, cardiac output, cardiac index, shortening fraction, indexed diastolic dimension, and indexed diastolic volume were calculated and compared between patient and control groups. Left ventricular mass and performance were slightly elevated in type 1 diabetic patients compared with 30 healthy control individuals. However, only cardiac output had borderline statistical significance (p = 0.06). The reason might be short duration (mean, 4.02 +/- 4.07 years) of diabetes in our patients group. In 18 of 47 patients the duration of type 1 diabetes was even less than two years. Relation of left ventricular mass to independent variables showed that, left ventricular mass was significantly correlated with stroke volume (p = 0.008), cardiac index (p = 0.0005), indexed systolic blood pressure (p = 0.0000199), indexed diastolic blood pressure (p = 0.0000172) and left ventricular contractility (p = 0.000273) in diabetic patients. Left ventricular contractility was also independently associated in diabetic patients with the indexed systolic and diastolic blood pressure (p = 0.0000755 and 0.000678 respectively). Albumin excretion, duration of diabetes, glycosylated hemoglobin (HbAlc), serum creatinine, and left ventricular preload did not have significant univariate correlation with left ventricular contractility.

New phosphate binding agents: ferric compounds

Several prior studies suggest that ferric compounds bind dietary phosphate and possess clinical potential as phosphate binding agents. Therefore, this study was conducted to measure the effect of several ferric compounds on intestinal phosphate binding and absorption. Balance studies lasting 2 to 4 wk were performed in normal and azotemic (achieved by subtotal nephrectomy) rats maintained on a 1.02% phosphorus diet supplemented with ferric salts (formulated to 0.95% Fe) or no ferric salt (control). In rats with normal renal function (average creatinine clearance, 4.0 ml/min per kg), the average net intestinal absorption of phosphate over all balance periods was 103.3 mg/d for the control group versus 84.7 mg/d for the ferric citrate group (P < 0.005). In the azotemic rats (average creatinine clearance, 3.3 ml/min per kg), the average net intestinal absorption of phosphate over all balance periods was significantly lower for the three ferric groups than the control groups (P < or = 0.02): 95.3 mg/d for the control group versus 75.6 mg/d for the ferric ammonium citrate-treated group (P = 0.058), 77.0 mg/d for the ferric citrate-treated group (P = 0.057), and 62.5 mg/d for the ferric chloride-treated group (P < 0.002). Urinary phosphate excretion fell, sometimes to an even greater extent than did intestinal absorption, yielding no net reduction in phosphate balance in these growing, young animals with relatively preserved renal function. Calcium balance was largely unaffected by the ferric compounds. There were trends toward decreased serum phosphorus and parathyroid hormone concentrations and increased iron and hematocrit in the ferric-treated azotemic groups. All tested ferric compounds were well tolerated, but animal growth was stunted in the ferric chloride animals compared with the control group. Phosphate binding was estimated at 85 to 180 mg per gram of elemental iron, which is comparable to other phosphate binding agents. Ferric salts decrease net intestinal phosphate absorption and hold promise for the treatment of phosphate retention in patients with renal failure.

Mutational spectrum of p53 gene in arsenic-related skin cancers from the blackfoot disease endemic area of Taiwan

To understand the role of p53 tumour suppressor gene in the carcinogenesis of arsenic-related skin cancers from the blackfoot disease endemic area of Taiwan, we collected tumour samples from 23 patients with Bowen's disease, seven patients with basal cell carcinomas (BCC) and nine patients with squamous cell carcinomas (SCC). The result showed that p53 gene mutations were found in 39% of cases with Bowen's disease (9/23), 28.6% of cases with BCC (2/7) and 55.6% of cases with SCC (5/9). Most of the mutation sites were located on exon 5 and exon 8. Moreover, the results from direct sequencing indicated that missense mutations were found at codon 149 (C-->T) in one case, codon 175 (G-->A) in three cases, codon 273 (G-->C) in three cases, codon 292 (T-->A) in one case, codon 283 (G-->T) in one case, codon 172 (T-->C) in one case and codon 284 (C-->A) in one case. In addition, silent mutations were also found in four cases. These mutations were located at codons 174, 253, 289 and 298 respectively. In immunohistochemistry analysis, p53 overexpression was found in 43.5% (10/23) of cases with Bowen's disease, 14% (1/7) of cases with BCC and 44% (4/9) of cases with SSC. These findings showed that p53 gene mutation rate in arsenic-related skin cancers from the blackfoot disease endemic area of Taiwan is high and that the mutation types are different from those in UV-induced skin cancers.

Factors affecting the mortality of sick newborns admitted to intensive care units

In order to provide better understanding of the factors affecting the mortality of sick newborns in the Taipei metropolitan area, data of newborns admitted to the intensive care units (ICU) were analyzed retrospectively according to the hospital type of care. Fourteen of the 19 hospitals with an ICU admitting sick newborns joined the data collection: 3 were local hospitals, 7 were regional hospitals and 4 were medical centers. Perinatal and neonatal data of 1083 sick newborns were analyzed: 60% were premature newborns and 58% were male newborns. The maternal referral rate was 7.8% and the neonatal transport rate was 36.2%. Fifty-nine percent of very low birth-weight newborns and 66% of extremely low birth-weight (ELBW) newborns were admitted to the medical centers. The two most common illnesses were perinatal asphyxia and respiratory distress syndrome. About 40% needed assisted ventilation. There were higher incidence of maternal referral, fetal distress, resuscitation in the delivery room, perinatal asphyxia, and necrotizing enterocolitis; lower incidence of meconium aspiration syndrome, sepsis and pneumothorax in newborns admitted to the medical center than those newborns admitted to other hospitals. A total of 153 newborns (14%) died. The most common cause of death was sepsis (22.9%). Multivariate logistic regression analysis revealed that factors significantly related to the mortality were gestational age < 28 weeks, congenital anomaly, sepsis, resuscitation in the delivery room, neonatal transport, congenital heart disease, hospital type of care, ELBW, pneumothorax and high-risk pregnancy. The results of the study stress the importance of regionalization of perinatal and neonatal care, organization of neonatal transport system, newborn resuscitation training, infection control, and delicate ventilatory care in the further improvement of the outcome of sick newborns in the Taipei metropolitan area.

DNA adduct formation by secondary metabolites of cyclopenta[cd]pyrene in vitro

In this study, calf thymus DNA was reacted in vitro with cyclopenta[cd]pyrene 3,4-epoxide (CPPE) or its metabolites, 3,4-dihydroCPP-3,4-diol (CPP-3,4-diol) and 4-hydroxy-3,4-dihydroCPP (4-OH-DCPP), activated with sulfotransferase. The adducts formed were analyzed by HPLC with fluorescence detection following enzymatic digestion of DNA to deoxynucleosides. We have shown previously that the major CPPE-reacted DNA adducts are cis-3-(deoxyguanosin-N2-yl)-4-hydroxy-3,4-dihydroCPP. Sulfotransferase activation of trans-CPP-3,4-diol yielded two adducts that were identical to the products resulting from the reaction of CPPE with DNA, while cis-CPP-3,4-diol gave very low covalent binding. Two adducts formed by sulfotransferase activation of 4-OH-DCPP were identical to the products of the reaction of synthetic 4-NaO3S-O-DCPP or sulfotransferase-activated 4-OH-DCPP with deoxyguanosine. These results indicate that guanine is the predominant site of CPP adduct formation in DNA, and that the 4-hydroxy-3-dGuo adducts can arise by reaction of DNA with either CPPE or sulfotransferase-activated trans-CPP-3,4-diol.

Pulmonary artery hemodynamics with varying degrees of valvular stenosis: an in vitro study

The study was to investigate the effects of varying degrees of valvular stenosis on the hemodynamics of the main (MPA), left (LPA), and right (RPA) pulmonary arteries. Particle flow visualization was used to examine the flow patterns in a series of pulmonary artery models manufactured out of glass. These glass models were made based on the geometry of the porcine pulmonary arteries with dilatation in the MPA and LPA. Also, detailed pressure mappings in the models were conducted using a side-hole catheter. As the valve became stenotic, a jet-like flow was observed in the M PA. A higher degree of valvular stenosis corresponded to a narrower jet. This jet-like flow was noted to deflect away from the centerline and impinge on the roof of the dilated MPA. Additionally, a notable pressure gradient across the deflected jet-like flow in the direction of its radius of curvature was seen. Moreover, secondary flows started to appear in the dilated MPA. This suggested that the change in geometry in the MPA, due to its dilatation, had a marked effect on the pulmonary artery hemodynamics. In the LPA and RPA, the strengths of the secondary flows increased as the valve became more stenotic. The flow patterns observed in the LPA appeared to be more disturbed than in the RPA, due to the poststenotic, dilatation present in the LPA. Pressure recovery along the axial direction in the M PA was observed for all the stenotic valves studied. As the degree of valvular stenosis increased, the transvalvular energy loss increased. Moreover, it was observed that the energy loss decreased progressively as the flow traveled downstream. This tendency was consistent with the phenomenon of pressure recovery observed in the pressure measurement. The study demonstrates the importance of analyzing biological flows from a three-dimensional viewpoint.

Phosphine-induced oxidative stress in Hepa 1c1c7 cells

Phosphine (PH3), from hydrolysis of metal phosphides, is an important insecticide (aluminum phosphide) and rodenticide (zinc phosphide) and is considered genotoxic and cytotoxic in mammals. This study tests the hypothesis that PH3-induced genotoxicity and cytotoxicity are associated with oxidative stress by examining liver (Hepa 1c1c7) cells for possible relationships among cell death, increases in reactive oxygen species (ROS) and lipid peroxidation, and elevated 8-hydroxyguanine (8-OH-Gua) in DNA. PH3 was generated from 0.5 mM magnesium phosphide (Mg3P2) to give 1 mM PH3 as the nominal and maximal concentration. This level causes 31% cell death at 6 h, measured by lactate dehydrogenase leakage, with appropriate dependence on concentration and time. The intracellular ROS level is elevated within 0.5 h following exposure to PH3, peaking at 235% of the control by about 1 h. Lipid peroxidation (measured as malondialdehyde plus 4-hydroxyalkenals) is increased up to 504% by PH3 at 6 h in a time-dependent manner. The level of 8-OH-Gua in DNA, a biomarker of mutagenic oxidative DNA damage analyzed by GC/MS, increases to 259% at 6 h after PH3 treatment. Antioxidants significantly attenuate the PH3-induced ROS formation, lipid peroxidation, 8-OH-Gua formation in DNA, and cell death, with the general order for effectiveness of GSH (5 mM) and D-mannitol (10 mM) (hydroxyl radical scavengers), then Tempol (2.5 mM) and sodium azide (3 mM) (superoxide anion and singlet oxygen scavengers, respectively). These studies support the hypothesis that PH3-induced mutagenic and cytotoxic effects are due to increased ROS levels, probably hydroxyl radicals, initiating oxidative damage.

Inhibition of calcitriol-induced monocyte CD14 expression by uremic toxins: role of purines

End-stage renal disease is associated with a defect in immunologic functions. Previous studies have demonstrated that uremic ultrafiltrate (UUF) contains factors that suppress calcitriol synthesis and its biological actions. In the present study, the effect of UUF on basal and calcitriol-induced membrane bound CD14 expression of monocytes activated by phorbol 12-myristate 13-acetate was evaluated. CD14 acts as a receptor for the complexes of lipopolysaccharide and lipopolysaccharide-binding protein. Monocytes isolated from normal donors were used for the assay of monocyte CD14 expression. A calcitriol induced rise in monocyte CD14 expression (1966+/-423 to 2421+/-436 fluorescence intensity) was found. However, UUF not only suppressed basal CD14 expression of monocytes (from 1966+/-423 to 1240+/-203, P < 0.05) but also significantly blunted calcitriol-induced CD14 expression (from 2421+/-436 to 1744+/-229, P < 0.05). HPLC fractionated UUF collected from 8 to 16 min (fraction 1, F1) and from 25 to 40 min (fraction 3, F3) also significantly suppressed the expression of CD14. Because purine derivatives coeluted within F1, their effect on monocyte CD14 expression was also tested. Uric acid, xanthine, and hypoxanthine was found to suppress basal as well as calcitriol-induced CD14 expression of monocytes in a dose-dependent manner. In conclusion, UUF contains factors that impair calcitriol activated function of monocytes.

Home oxygen therapy for chronic lung disease in very low-birth-weight infants

Prolonged hospitalization in infants suffering from chronic lung disease who require continuous oxygen therapy can be avoided by oxygen administration at home. In the period from August 1995 to September 1996, 155 very low-birth-weight (VLBW) infants were consecutively admitted to the neonatal intensive care unit of Mackay Memorial Hospital. Of the 155 infants, 72% (111/155) survived to discharge. However, 34% (38/111) of the survivors developed chronic lung disease. Twenty-three infants with chronic lung disease underwent home oxygen therapy after 107.0 +/- 43.6 days of hospitalization. The mean duration of home oxygen therapy was 4.3 +/- 3.4 months. In the first year after discharge, 91% of the patients required rehospitalization. One patient died during the fourth hospitalization. Follow-up information on growth and development at one year of corrected age was available for 19 patients. Five of the 19 patients had a body weight below the 5th percentile. Five of the 19 infants were mentally retarded and 12 of the 19 patients had significantly delayed motor development. In conclusion, carefully supervised home oxygen therapy permits safe early discharge of selected VLBW infants with chronic lung disease. Their somatic and psychomotor development should be carefully followed up.