[Effect of sample solvents on retention in packed column supercritical fluid chromatography]

Factors affecting the retention in supercritical fluid chromatography(SFC) on C18 and NH2 packed columns have been studied. These factors include the sampling solvent, continuous injection, stationary phase type and concentration of modifier. When supercritical carbon dioxide or low concentration(less than 0.5%) of methanol is employed as the mobile phase, retention time increases with the polarity of the solvent on NH2 column, while it keeps almost constant on C18 column. Methanol will cover the active sites on the surface of the bonded phase, forming the "pseudo" stationary phase, which will lower the interaction between the analytes and the stationary phase, hence the shorter will be the retention time. The hydrogen bond between stationary phase (including the amino group and the remaining hydroxyl group) and methanol is the most obvious. So it's quite more evident on NH2 column than on C18 column that the delaying effect of the solvent, with methanol, acetone and chloroform in decreasing sequence, encourages the elution of the analytes during continuous injections. The elution will recover to the first injection after adequate interval has passed, i.e., more than 10 column volumes. When the methanol concentration is greater than 1.0% in carbon dioxide, the effect decreases and becomes negligible. The solvent effect is significant to the reasonable injection and reproducible chromatographic data in packed column SFC.

[Determination of major components in Psoralea corylifolia L. by using supercritical fluid extraction (SFE)]

A method based on SFE and CGC has been developed for qualitative and quantitative analysis of major components in Psoralea corylifolia L.. The orthogonal design method and the analysis of variance are used to optimize the five variables (temperature, pressure, volume of modifier, static extraction time and CO2 dynamic extracting volume) of SFE and the optimized conditions listed as follows: temperature 70 degrees C, pressure 38.5 MPa, static extraction 1 min, dynamic extraction 7 mL and 60 microL CHCl3 as modifier. The recoveries of psoralen and isopsoralen are 96.93% (RSD 1.87%) and 98.43% (RSD 2.06%) respectively. Being compared with conventional methods, the SFE as an alternative technique for sample preparation will be most useful in the quality control of Chinese traditional medicines.

Early newborn hospital discharge and readmission for mild and severe jaundice

OBJECTIVES

To further explore the relationship of early newborn hospital discharge and readmission for jaundice, and to determine if early hospital discharge was associated with increased severity of jaundice among those readmitted.

METHODS

We performed a population-based case-control study using Washington State vital statistics, birth certificates, and hospital discharge abstracts from 1991 to 1995. Cases included 750 infants readmitted to the hospital for jaundice in the first 2 weeks of life; controls included 3192 infants not readmitted. Infants with severe medical conditions and those delivered by cesarean section were excluded. Early hospital discharge was defined as fewer than 30 hours in the hospital, late hospital discharge, 30 to 78 hours. We assessed the risk for hospital readmission for jaundice, for hospital readmissions classified as brief (< or =2 days) or prolonged (>2 days), and for hospital readmissions classified as uncomplicated or complicated.

RESULTS

Infants discharged from the hospital early were at increased risk for jaundice (odds ratio, 1.34 [95% confidence interval, 1.10-1.64] adjusted for birth year, gestational age, maternal race and age, parity, payer, and infant sex). The risk associated with early hospital discharge was similar regardless of whether the hospital readmission was brief or prolonged and complicated or uncomplicated. One hundred twenty-two infants would have to stay for longer than 30 hours to avoid 1 jaundice readmission.

CONCLUSIONS

While newborns discharged from the hospital early are at increased risk for hospital readmission for jaundice, the clinical significance is limited. Mandating longer neonatal stays may not be the most effective strategy to prevent hospital readmission for jaundice and its complications.

[Single-pump on-line addition of modifier for supercritical fluid chromatography]

Modified CO2 as mobile phase is usually necessary for packed-column supercritical fluid chromatography. Single syringe pump was applied in this work to add modifier through a parallel connection device, which can maintain constant and stable volume fraction of modifier without any contamination of the pump. Viscosity of the modifiers (here are methanol and acetone) and the length of the CO2 pipe line/modifier pipe line can affect the volume fraction. Volume fractions of methanol and acetone were determined by gas chromatography and ultraviolet spectrometry respectively and their rules of variation were also examined. It shows that the volume fraction of methanol is lower than that of acetone under similar condition. With fixed modifierr line, the longer the CO2 line is, the higher the volume fraction will be. The new device can conveniently alter the nature and ratio of the modifier with quite stable volume fraction. The online addition device can tentatively replace the dual-pump system.

Bronchiolitis-associated hospitalizations among US children, 1980-1996

CONTEXT

Respiratory syncytial virus (RSV) causes more lower respiratory tract infections, often manifested as bronchiolitis, among young children than any other pathogen. Few national estimates exist of the hospitalizations attributable to RSV, and recent advances in prophylaxis warrant an update of these estimates.

OBJECTIVES

To describe rates of bronchiolitis-associated hospitalizations and to estimate current hospitalizations associated with RSV infection.

DESIGN AND SETTING

Descriptive analysis of US National Hospital Discharge Survey data from 1980 through 1996.

PARTICIPANTS

Children younger than 5 years who were hospitalized in short-stay, non-federal hospitals for bronchiolitis.

MAIN OUTCOME MEASURE

Bronchiolitis-associated hospitalization rates by age and year.

RESULTS

During the 17-year study period, an estimated 1.65 million hospitalizations for bronchiolitis occurred among children younger than 5 years, accounting for 7.0 million inpatient days. Fifty-seven percent of these hospitalizations occurred among children younger than 6 months and 81 % among those younger than 1 year. Among children younger than 1 year, annual bronchiolitis hospitalization rates increased 2.4-fold, from 12.9 per 1000 in 1980 to 31.2 per 1000 in 1996. During 1988-1996, infant hospitalization rates for bronchiolitis increased significantly (P for trend <.001), while hospitalization rates for lower respiratory tract diseases excluding bronchiolitis did not vary significantly (P for trend = .20). The proportion of hospitalizations for lower respiratory tract illnesses among children younger than 1 year associated with bronchiolitis increased from 22.2% in 1980 to 47.4% in 1996; among total hospitalizations, this proportion increased from 5.4% to 16.4%. Averaging bronchiolitis hospitalizations during 1994-1996 and assuming that RSV was the etiologic agent in 50% to 80% of November through April hospitalizations, an estimated 51, 240 to 81, 985 annual bronchiolitis hospitalizations among children younger than 1 year were related to RSV infection.

CONCLUSIONS

During 1980-1996, rates of hospitalization of infants with bronchiolitis increased substantially, as did the proportion of total and lower respiratory tract hospitalizations associated with bronchiolitis. Annual bronchiolitis hospitalizations associated with RSV infection among infants may be greater than previous estimates for RSV bronchiolitis and pneumonia hospitalizations combined.

Ankle arthrodesis: internal non-compression arthrodesis versus internal compression arthrodesis

Ankle arthrodesis is still considered to be the standard treatment for most disabling types of ankle arthritis, but fusion methods are varied. We report our experience of ankle arthrodesis and compare a group of 34 cases treated by Blair's non-compression arthrodesis to another group of 32 cases treated by internal compression arthrodesis using two crossed screws. The same surgeon performed all the operations. The Blair's non-compression arthrodesis group included 21 males and 13 females with an average age of 42 y/o (range 18-70 y/o) and an average follow up period of 38.6 months (range 26-62 months). The union rate was 91.2% and the average union time was 5.6 months (range 2-10 months). There were three cases of non-union. The cross-screw compression arthrodesis group included 20 males and 12 females with an average age of 45 y/o (range 20-86 y/o) and an average follow up period of 38.3 months (range 15-81 months). The union rate was 96.9% and the average union time was 2.7 months (range 1.5-4.4 months). There was one case of non-union. We conclude that our cross-screws compression arthrodesis with its shorter fusion time was found to be superior to the Blair's non-compression arthrodesis.

Viral induction, transmission and apoptosis among cells infected by a Human Intracisternal A-type retrovirus

Sjogren's Syndrome, a systemic autoimmune disease, is characterized by lymphocytic infiltration of the salivary or lacrimal glands, producing xerostomia or xerophthalmia. Although definitive proof of viral etiology has not been established, a cell line containing viral particles termed Human Intracisternal A-type Particles (HIAP) resulted from co-culture with patient lip biopsies. We stimulated these chronically infected cells with phorbol myristate acetate (PMA) in an effort to enhance production of viral particles for further characterization. We report that the virus present in the HIAP cell line can be induced to become lytic when subjected to PMA and that there is a difference in the effects of PMA on H9 and HIAP cell groups, with apparent protection from apoptosis due to PMA being exerted by viral presence. Delayed apoptosis may prolong exposure of the foreign/self complex, thus enhancing an autoimmune response. Polyacrylamide gel electrophoresis (PAGE) revealed the presence of new peptides in pellets of supernatants of PMA-stimulated HIAP cells, with prominent bands at 55 and 43 kDa, and several fainter ones. HIAP infection was transferred by cell-free filtered supernatants from stimulated cells to H9 cells, which became identical to parent HIAP cells by PAGE and fluorescence activated cell sorter.

Asthma prevalence among American Indian and Alaska Native children

OBJECTIVES

Although asthma is the most common chronic childhood illness in the United States, little is known about its prevalence among American Indian and Alaska Native (AI/AN) children. The authors used the latest available household survey data to estimate the prevalence of asthma in this population.

METHODS

The authors analyzed data for children ages 1 through 17 years from the 1987 Survey of American Indians and Alaska Natives (SAIAN) and the 1987 National Medical Expenditure Survey (NMES). At least one member of each AI/AN household included in the SAIAN was eligible for services through the Indian Health Service.

RESULTS

The weighted prevalence of parent-reported asthma was 7.06% among 2288 AI/AN children ages 1-17 (95% CI 5.08, 9.04), compared with a US estimate of 8.40% for children ages 1-17 based on the 1987 NMES (95% CI 7.65, 9.15). The AI/AN sample was too small to yield stable estimates for a comparison between AI/AN children and all US children when the data were stratified according to household income and metropolitan vs non-metropolitan residence. The unadjusted asthma prevalence rates were similar for AI/AN children and for children in the NMES sample.

CONCLUSIONS

In 1987, the prevalence of parent-reported asthma was similar for AI/AN children in the SAIAN sample and for children in the NMES sample. More recent data are needed to better understand the current prevalence of asthma among AI/AN children.

Preoperative cardiac evaluation of women for noncardiac surgery

Cardiac risk assessment is a crucial aspect of perioperative evaluation because it is estimated that 1 million people, regardless of gender, will have perioperative cardiac complications at a cost of 20 billion dollars. Unfortunately, establishment of optimal guidelines for selected patient subgroups, particularly women, are lacking. More prospective studies are needed to help evaluate the most cost-effective, yet accurate way to noninvasively assess the presence of coronary artery disease in women.

The safety of newborn early discharge. The Washington State experience

CONTEXT

While early discharge of newborns following routine vaginal delivery has become common practice, its safety has not been firmly established.

OBJECTIVE

To assess the risk for rehospitalization following newborn early discharge.

DESIGN

Population-based, case-control study.

SETTING

Washington State linked birth certificate and hospital discharge abstracts covering 310578 live births from 1991 through 1994.

PATIENTS

Case patients were 2029 newborns rehospitalized in the first month of life. Control subjects were 8657 randomly selected newborns not rehospitalized and frequency matched to case patients on year of birth. Cesarean deliveries, multiple births, and births at less than 36 weeks' gestation were not included.

MAIN OUTCOME MEASURE

Stratified analyses and logistic regression were performed to assess the risk for rehospitalization within a month of birth after early discharge (<30 hours after birth) compared with later discharge (30-78 hours after birth).

RESULTS

Seventeen percent of newborns were discharged early. Newborns discharged early were more likely to be rehospitalized within 7 days (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.11-1.47), 14 days (OR, 1.16; 95% CI, 1.03-1.32), and 28 days (OR, 1.12; 95% CI, 1.00-1.25) of discharge than newborns sent home later. Subgroups at increased risk for rehospitalization following early discharge included newborns born to primigravidas (OR,1.25; 95% CI, 1.07-1.45), mothers younger than 18 years (OR, 1.22; 95% CI, 0.79-1.91), and mothers with premature rupture of membranes (OR, 1.41; 95% CI, 0.85-2.36). Early discharge was also associated with an increased risk of readmission for jaundice, dehydration, and sepsis.

CONCLUSION

Newborns discharged home early (<30 hours after birth) are at increased risk for rehospitalization during the first month of life.

Organotin concentrations in three intertidal neogastropods from the coastal waters of Taiwan

This study was aimed to determine organotin concentrations in the muricids Thais clavigera, Thais tuberosa and Morula granulata on an island wide scale and to find an adequate bioindicator species for long-term monitoring purpose. Samples were collected from the coast of Taiwan and vicinity islands with organotin analysis by graphite furnace atomic absorption spectrophotometry. Because triphenyltin (TPT) could not be discriminated from tributyltin (TBT) by the extraction method, organotins were measured as TBT + TPT and total hexane extractable organotins. Severity of imposex in the muricid population samples expressed as relative penis size (RPS) indices were calculated and compared to determine a suitable bioindicator species. In T. clavigera, T. tuberosa and M. granulata, TBT + TPT were 17-157, 1-44 and 117-1343 ng Sn g(-1) dry wt, respectively. And total organotins varied in the range of 181 to 1125, 23 to 44 and 229 to 1402 ng Sn g(-1) dry wt, respectively. A positive correlation was found between TBT + TPT and total organotins in M. granulata (TBT + TPT = Total organotins x 1.01-110.79; R2=0.97; p<0.001). At the site of Dapaisha, total organotins in M. granulata was 10 times higher than in T. tuberosa (i.e. 242 versus 23 ng Sn g(-1) dry wt). No signs of imposex were found in T. tuberosa (a single site in two subsequent years) and in M. granulata (seven collection sites). The degree of imposex (RPS) of T. clavigera varied from 0.2 to 38.1%. The RPS indices from fishing harbors were not higher than from rocky shores and oyster culture sites. No correlation was found between RPS indices and concentrations of TBT + TPT or total organotins. M. granulata seemed to be insensitive to organotin pollution although organotins were also detected. Our results indicate that organotin pollution is wide spread in coastal waters of Taiwan and pollutants at least include butyltins and phenyltins. As a bioindicator species, T. clavigera is more appropriate than T. tuberosa and M. granulata to monitor organotin contamination.

Pregnancy among American Indian adolescents: reactions and prenatal care

PURPOSE

Adolescent childbearing is twice as common among Native Americans as among all US races combined. Despite this, little is written about the psychosocial context or prenatal care of pregnant Native American adolescents. The objective of this study was to explore the reactions and prenatal care of Navajo and Apache adolescents delivering infants at Shiprock Indian Hospital, New Mexico, between January and March 1991, and Whiteriver Indian Hospital, Arizona, between May and June 1991.

METHODS

Of the 25 eligible adolescents aged 19 years and younger, 15 Navajo and 5 Apache participants were interviewed within 24 hours of delivery. The interview consisted of 121 questions divided into 5 areas: sociodemographics, personal and family reactions to the pregnancy, knowledge and attitudes toward prenatal care, barriers to care, and ways to improve access to care.

RESULTS

The mean age was 17.4 +/- 1.1, 6 were married, and 13 were primiparous. According to the Maternal Health Services Index, 5 adolescents received adequate, 13 intermediate, and 2 inadequate prenatal care. During the pregnancy, 3 adolescents used tobacco, 3 used alcohol, and none admitted to other drugs. Although only 1 adolescent planned the pregnancy, 15 were not using contraception when they became pregnant. In exploring reactions to the pregnancy, 13 adolescents were afraid to tell their families and 4 concealed the pregnancy until confronted. During the pregnancy, 7 adolescents described loneliness and 6 expressed suicidal ideation. Although over half reported no barriers to obtaining prenatal care, barriers that were noted by the remainder included transportation, family problems, and missing school.

CONCLUSION

We conclude that pregnancy among many American Indian adolescents is unplanned and characterized by uncertainty and fear of disclosure, resembling the reactions to pregnancy of other adolescent populations. Furthermore, despite universal access to health services, many American Indian adolescents continue to experience barriers to care and receive intermediate or inadequate prenatal care. These preliminary findings suggest further research may help clarify how adolescent reactions to pregnancy and knowledge of prenatal care affect health care utilization.

[A study on the protective effect of metallic chelators on ischemia-reperfusion injury of isolated rat heart]

A Langendorff isolated rat heart preparation was used to determine the effect of the metallic chelators, deferoxamine and penicillamine on the extent of myocardial ischemia reperfusion injury. Each heart was subjected to 15-60 minutes of total ischemia at 37 degrees C followed by 15-60 minutes of reperfusion with either saline, deferoxamine (0.61 mmol/L), or penicillamine (30 mmol/L) treated perfusate. Reperfusion injury was assessed by the production of free radicals with electronic spin resonance spectroscopy and spin trap PBN, by the amount of creatine phospholipase released into the perfusate, by the changes in the myocardial vascular resistance, and by pathologic examination of myocardium. The results showed that the drug treated groups released significantly less radical adducts of PBN (P < 0.01) and creatine phosphokinase into the perfusate than the saline treated group (P < 0.01). The mean vascular resistance significantly increased in the saline treated group than in the drug treated groups (P < 0.01). Ultrastructural examination showed prominent attenuation of mitochondrial swelling in drug treated groups in comparison with the saline one. These findings indicated that both deferoxamine and penicillamine can protect the isolated rat heart from ischemia reperfusion injury. The possible mechanism of which is that metallic chelators block the transitional metal-catalyzed fenton reaction, and subsequently decrease the production of hydroxyl radical.

Lymphocyte subset distribution and natural killer cell activity in men with idiopathic hypogonadotropic hypogonadism

Sex-related differences in immune responsiveness are mediated at least in part by sex steroid hormones. Lymphocyte subset distribution in peripheral blood and natural killer cell function both have been reported to be under hormonal control. In order to gain more insight into sex steroid hormone action on the immune system, we have measured the lymphocyte subset distribution and natural killer cell activity in 18 men with idiopathic hypogonadotropic hypogonadism before treatment, and after hormonal treatment had normalized plasma testosterone levels. In untreated patients, the mean plasma testosterone concentrations were significantly lower than those in the treated men (3.0 +/- 0.5 nmol/l vs 16 +/- 1.7 nmol/l, p less than 0.001). The percentage of peripheral CD3+ lymphocytes, CD8+ cells, the CD4+/CD8+ ratio, and the natural killer cell activity of peripheral mononuclear cells measured in a 51Cr release assay against target K 562 cells did not differ between patients with idiopathic hypogonadotropic hypogonadism and healthy adults, and most importantly, did not change during hormonal treatment which normalized plasma testosterone levels in the patients. In contrast, the percentage of peripheral CD4+ cells was significantly higher in untreated patients compared with normal adult subjects or patients with idiopathic hypogonadotropic hypogonadism after hormonal treatment that resulted in normal plasma testosterone levels (53 +/- 2 vs 47 +/ 2, p less than 0.05). It should be noted that the percentage of peripheral CD16+ cells was significantly lower in untreated men with low plasma testosterone levels than in normal controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolism and DNA single strand breaks induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and its analogues in primary culture of rat hepatocytes

Previous studies have shown that the tobacco specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), is hepatocarcinogenic and results in alkylation of hepatic DNA in F344 rats. In this study, we have characterized the metabolism of NNK in cultured rat hepatocytes and have established the relationship between various metabolic pathways and the induction of DNA single strand breaks. DNA fragmentation by NNK and two other related N-nitrosamines, N'-nitrosonornicotine and nitrosodimethylamine, were compared. Metabolism of [5-3H]NNK (4.5 microM) by carbonyl reduction, alpha-carbon hydroxylation, and pyridine N-oxidation was linear from 0 to 6 h and with 0 to 2 x 10(6) hepatocytes. Using the alkaline elution assay, we observed that NNK induces DNA single strand breaks (SSB) in a dose (1-10 mM) and time (0.5-6 h) dependent manner. SSB induced by NNK (5 mM; rate of elution between 3 and 9 h, 0.117) are rejoined partially within 2 h (rate, 0.039) and totally 12 h after exposure. NNK N-oxide (5 mM) produces a smaller number of SSB (rate, 0.017) than NNK (rate, 0.105) suggesting that pyridine N-oxidation of NNK is a deactivation pathway. Hydrolysis of carbethoxy-nitrosaminomethane and 4-(N-carbethoxy-N-nitrosamino)-1-(3-pyridyl)butanone yields methyldiazohydroxide and 4-(3-pyridyl)-4-oxobutyl-diazohydroxide, respectively. These two alkylating intermediates are generated during alpha-carbon hydroxylation of NNK. After treatment of hepatocytes with 5 microM carbethoxynitrosaminomethane and 1 mM 4-(N-carbethoxyl-N-nitrosamino)-1-(3-pyridyl)butanone, the rates of DNA elution were 0.092 and 0.120, respectively. Carbonyl reduction of NNK leads to 4-(methylnitrosamino)-1-(3-pyridyl)butan-1-ol (NNAl). Reaction of NNK with methyl magnesium iodide gives 1-MeNNAl with 82% yield, NNAl but not 1-MeNNAl can be reoxidized to NNK. Both 5 mM NNAl (rate, 0.073) and 5 mM 1-MeNNAl (rate, 0.054) induce SSB indicating that NNAl does not require reconversion to NNK to be activated to DNA damaging intermediates. alpha-Methylene hydroxylation of NNK results in an equimolar formation of methyldiazohydroxide and 4-oxo-4-(3-pyridyl)-butanal. This aldehyde, at a concentration of 1 mM, induces the same frequency of SSB (rate, 0.116) as 5 mM NNK (0.105) and could possibly play a role in the carcinogenicity of NNK.(ABSTRACT TRUNCATED AT 400 WORDS)

Experimental and clinical investigation on oxiconazole

A new antimycotic imicazole drug, oxiconazole, used both in vitro and in vivo in the treatment of 212 cases of tinea corporis, tinea cruris and tinea pedis is reported. In vitro, it shows marked antimycotic effect against 24 strains of pathogenic fungi except those of Wangiella dermatitides and 3 strains of Aspergilli. The minimal inhibition concentration (MIC) to Epidermophyton floccosum and Candida guilliermondi are 1 microgram/ml and 0.5 microgram/ml. The cure rate of 2% cream of oxiconazole in 124 cases of tinea corporis and tinea cruris is 90.3%, and in 88 cases of tinea pedis, 89.78%.

Lung abscess caused by Eikenella corrodens: report of a case

Eikenella corrodens is a slow-growing, facultatively anaerobic, gram-negative bacillus. It is part of the normal flora of the human upper respiratory tract. We report a 68-year-old man who developed lung abscesses caused by E. corrodens while on long-term corticosteroid therapy for polymyositis. It was isolated by percutaneous transthoracic aspiration of an abscess under real-time sonographic guidance. The organism has a very unusual antimicrobial susceptibility: sensitive to penicillin, ampicillin, cephapirin, chloramphenicol, minocycline and erythromycin but resistant to clindamycin, oxacillin and gentamicin. The patient was treated empirically with penicillin G and gentamicin. The latter was discontinued after the results of the bacterial culture and sensitivity test were available. He was discharged one month later with marked improvement. Our report clearly demonstrates that E. corrodens can be the sole pathogen of a respiratory tract infection.

Effect of amiodarone on the disposition of procainamide in the rat

We examined the effect of amiodarone on the disposition of procainamide in the rat to determine the mechanism of a reported interaction between amiodarone and procainamide and to determine the effect of amiodarone on drug acetylation. Animals received a 5-d pretreatment with amiodarone hydrochloride (100 mg/kg) or diluent prior to the intravenous administration of 50 mg/kg of procainamide hydrochloride. The plasma clearance, volume of distribution, and half-life of procainamide did not significantly differ between the two groups. The urinary recovery of N-acetylprocainamide was increased by 31% (p less than 0.01) in amiodarone pretreated animals. However, there was no change in the partial clearance of procainamide to N-acetylprocainamide. Neither the renal clearance of procainamide nor N-acetylprocainamide was altered by amiodarone pretreatment. These data suggest that amiodarone interacts with procainamide by reduction of an alternate pathway of elimination, possibly oxidative metabolism.

Effect of amiodarone and desethylamiodarone on the pharmacokinetics of antipyrine in the rat

The effect of amiodarone on hepatic drug metabolism in vivo was examined in the rat using antipyrine as a model substrate. Pretreatment with oral amiodarone hydrochloride, 100 mg/kg/day, for 5 days resulted in a 19% reduction in antipyrine clearance and a 22% increase in half-life. The administration of single oral doses of amiodarone hydrochloride, 100 mg/kg, 1 or 5 hr prior to antipyrine administration had no significant effect on antipyrine pharmacokinetics. The administration of a single intravenous dose of amiodarone hydrochloride, 50 mg/kg, reduced antipyrine clearance by 32% and increased the half-life by 46%. The desethyl metabolite of amiodarone was also found to reduce antipyrine clearance (21%) after a single oral dose of 100 mg/kg.

Recognition of the alpha-1 and alpha-2 domains of H-2 molecules by allospecific cloned T cells

Previously we had shown that allospecific bulk cultures of cytolytic T lymphocytes lysed the products of cloned class I major histocompatibility genes expressed after DNA-mediated gene transfer. In these experiments, performed by using cloned allospecific T cell effectors, a T cell hybridoma, and recombinant DNA technology, we have been able to map determinants recognized by these T cell clones to the alpha-1 domain of H-2Dd and the alpha-2 domain of H-2Ld (four of eight clones). Target cells used were L cells (H-2k), expressing wild type or hybrid H-2 antigens of H-2d origin. Thus, for the first time determinants recognized by cloned T cells are found in the recombined alpha-1 and alpha-2 domains.