Deterioration of detectable human immunodeficiency virus serum p24 antigen in samples stored for batch testing.

Virologic measurements are becoming important surrogate markers for therapeutic efficacy in clinical trials with human immunodeficiency virus (HIV)-infected subjects. One such marker which is inexpensive and easily evaluated is the HIV p-24 antigen. To determine the storage stability of p24 antigen assayed by enzyme-linked immunosorbent assay of serum collected during clinical trials, a retrospective analysis was performed. The p24 antigen results were available from four Adult or Pediatric AIDS Clinical Trials Group protocols: studies 047, 050, 128, and 213. Paired samples (n = 930) which were assayed by ELISA for p24 antigen both in real time and in batch were analyzed for agreement. Batch and real-time values were correlated; however, there was a lack of agreement which increased with prolonged storage time of batched samples and greater p24 antigen levels. The p24 antigen values were significantly lower in the batched samples, which had a maximum storage time of 1,548 days. The degradation rate of p24 antigen per year was 0.052 log10 for samples with less than 30 pg/ml, 0.197 log10 for those with 30 to 100 pg/ml, and 0.245 log10 for those with > 100 pg/ml. Due to degradation over time, use of p24 antigen values from batch assays with long-term storage could bias study results toward a lack of treatment effect. On the basis of these results we make the following recommendations. (i) Samples should be assayed either in real time by laboratories undergoing quality assurance or in batch with short-term storage (less than 1 year). (ii) When real-time assays are to be performed, the serum samples should not be stored at 4 degrees C, but should be frozen immediately after processing and stored frozen until tested.     

Differences in dietary intake associated with smoking status

This study was designed to identify and describe smoking-related differences in dietary and nutritional factors that are potential independent predictors of cancer risk or effect modifiers or confounders of tobacco-cancer relationships. Data were obtained from a large hospital-based case-control study which was designed to estimate the cancer risk from various tobacco products and consisted of 465 male and 300 female incident lung cancer cases and 870 male and 556 female hospitalized patient controls matched on sex and age (+/- 5 years). Nutritional data were analysed as log-transformed frequencies of thirty food items, nine factor scores generated to describe overall patterns of dietary intake, and estimated daily nutrient scores for fat, vitamin A, fibre, and cholesterol. In general, the dietary habits of ex-smokers more closely resembled those of never-smokers than those of current smokers. We found that after controlling for case-control status, education, alcohol consumption, and age, there were many more significant differences in nutritional exposures by smoking status than could be explained merely by chance. For both sexes we observed significantly increased consumption of fruits and higher vitamin A and fibre scores in non-smokers compared to current smokers (for any smoking vs non-smoking comparison the P-value was always less than 0.002, 0.01, and 0.007, respectively). A similar but weaker relationship was observed for high-fat, sweet foods such as ice cream. An inverse association, also of smaller magnitude, was found for other high-fat foods items. Implications for further study and strengths and weaknesses of the current study are discussed.     

Ewingella americana: recurrent pseudobacteremia from a persistent environmental reservoir.

From September 1981 through April 1984, 20 patients at one hospital were identified with Ewingella americana pseudobacteremia. Case-control studies demonstrated an association between having a positive blood culture for E. americana and having blood for culture obtained simultaneously with blood obtained for coagulation studies (15 of 19 case patients versus 4 of 38 controls; P = 4.5 X 10(-7)). Review of blood-drawing procedures showed that blood for coagulation studies and culture was drawn with the same syringe, and coagulation tubes were filled before blood culture tubes. Some phlebotomists were not using new sterile needles to inoculate blood culture bottles. Collection tubes for coagulation studies were prepared in the hospital, and E. americana was isolated from all 52 unused coagulation tubes tested. Solutions prepared in the hospital may constitute a persistent inanimate environmental reservoir for this uncommon microorganism. Pseudobacteremia can result in unnecessary antimicrobial therapy for some patients, incurring the risks of adverse drug reactions, selection of drug-resistant bacteria, and increased health care costs.     

Quantification of Human Immunodeficiency Virus Type 1 RNA Levels in Plasma by Using Small-Volume-Format Branched-DNA Assays

We have developed small-volume (50 or 250 μl)-format branched-DNA assays for human immunodeficiency virus type 1 (HIV-1) RNA for use with specimens in which the volume is limited and/or a high viral load is anticipated. These formats exhibited good correlation with the standard 1-ml format; high specificity, reproducibility, and linearity; and no significant difference in the quantification of HIV-1 subtypes.     

Rabbit antisera to the variable region domains of an anti-alpha(1----6) dextran using E. coli-produced VL and VH fusion proteins as immunogens.

Bacteria were engineered for the expression of mouse immunoglobulin light chain variable region (VL) and heavy chain variable region (VH) fusion proteins. cDNAs encoding the VL and VH of anti-alpha(1----6)dextran hybridoma protein 19.22.1 were inserted into the pATH 10 prokaryotic expression vector downstream of trp operon sequences. V domains joined to approximately 330 amino acids of the trp E gene product encoded by the expression plasmids accumulated at high levels in E. coli. In addition, the VL domain was expressed with a 15 amino acid extension at low levels in lon mutant bacteria. The trp E-VL and trp E-VH proteins were used to raise antisera in rabbits and the V specificity of the sera demonstrated.     

A dinucleotide mutation in the endothelin-B receptor gene is associated with lethal white foal syndrome (LWFS); a horse variant of Hirschsprung disease

Lethal white foal syndrome (LWFS) is a congenital anomaly of horses characterized by a white coat colour and aganglionosis of the bowel, which is similar to Hirschsprung disease (HSCR). We decided to investigate possible mutations of the endothelin-B receptor gene ( EDNRB ) in LWFS as recent studies in mutant rodents and some patients have demonstrated EDNRB defects. First, we identified a full-length cDNA for horse EDNRB . This cDNA fragment contained a 1329 bp open reading frame which encoded 443 amino acid residues. The predicted amino acid sequence was 89, 91 and 85% identical to human, bovine and mouse as well as rat EDNRB respectively, but only 55% identical to the human, bovine and rat endothelin A receptor (EDNRA). Secondly, sequence analysis, together with allele-specific PCR and the amplification- created restriction site (ACRS) technique, revealed a dinucleotide TC-- >AG mutation, which changed isoleucine to lysine in the predicted first transmembrane domain of the EDNRB protein. This was associated with LWFS when homozygous and with the overo phenotype when heterozygous.      

Stabilities of free and complexed human immunodeficiency virus p24 antigens during short- and long-term storage.

By the standard p24 assay there was a 25 to 27% decrease in free p24 antigen in serum after storage at 4 degrees C over 14 days but no loss at -70 degrees C. There was no loss at either temperature by the immune complex dissociation (ICD) procedure. Furthermore, there was no significant loss of detectable p24 in serum by either the ICD or the standard p24 assay after 700 days of storage at -70 degrees C.     

Relationship between HLA-DRB1 and DQ alleles and the genetic susceptibility to type 1 diabetes

Objective　To study the relationship between human leukocyte antigen (HLA)-DRB1 and DQ alleles and the genetic susceptibility of type 1 diabetes in North Chinese children. Methods　Polymerase chain reaction (PCR) techniques were used to amplify the second exon of DRB1 and DQ alleles, after which sequence specific olignucleotide probe (SSOP) dot blot hybridization techniques were used to analyze the amplified products. Results　DRB1*0301, DQA1*0301, DQB1*0201 alleles and DRB1*0301-DQA1*0501-DQB1*0201 haplotype were significantly increased in patients, while DQA1*0103 and DQB1*0601 alleles were significantly increased in controls. The distribution of DR4 and DR9 haplotypes in patients and controls were not significantly different, but DR3/DR4 and DR4/DR9 heterozygotes were significantly increased in patients. Conclusions　DRB1*0301, DQA1*0301 and DQB1*0201 confer susceptibility while DQA1*0103 and DQB1*0601 confer protection to type 1 diabetes. DRB1*0301-DQA1*0501-DQB1*0201 haplotype offers a predisposition to type 1 diabetes in North Chinese. Although the distribution of DR4 and DR9 in patients and controls had no significant difference, DR3/DR4 and DR3/DR9 heterozygotes were significantly increased in patients, showing that the susceptive effects of DR3 and DR4 or DR4 and DR9 haplotypes could be added up.     

Pharmaceutical service differences between teaching and community hospitals

The purpose of this study was to inventory the highly specialized units maintained in teaching hospitals and compare and contrast the scope and level of pharmaceutical services provided in teaching and similar-size community hospitals. In 1989, a 30-item questionnaire was mailed to a sample of 120 teaching hospitals. The scope and level of services provided was compared with similar size hospitals in the 1989 American Society of Hospital Pharmacists' survey of hospital-based pharmaceutical services. Teaching hospitals maintain more licensed and occupied beds, are more likely to be a member of a nonprofit multisystem organization, maintain many specialized care units and high speed transportation vehicles, exercise more control over specialized drugs and products, provide a broader array of pharmacy services to ambulatory patient populations, offer a more extensive and broader array of clinical services, maintain more extensive drug information resources, exercise more comprehensive formulary management initiatives, engage in broader diversified service initiatives, and generate 50% more annual pharmacy costs per occupied bed than do similar-sized community hospitals. Teaching hospitals are complex organizations that provide care to patients who require higher levels of pharmaceutical services than those provided in similar-sized community hospitals.