Complete deletion of the androgen receptor gene: definition of the null phenotype of the androgen insensitivity syndrome and determination of carrier status.

The molecular basis of androgen insensitivity was investigated in a family with the complete form of the syndrome. Polymerase chain reaction amplification and Southern blot analysis of genomic DNA revealed a deletion of the entire androgen receptor (AR) gene in affected individuals. The carrier status of female members of this family was examined using a HindIII restriction fragment length polymorphism associated with the AR gene. Obligate carriers were hemizygous for one of the two alleles at this locus, while heterozygosity for the polymorphic alleles, implying the presence of two copies of the AR gene, indicated noncarrier status. This conclusion was supported by gene dosage studies using comparative densitometric analysis of Southern blots hybridized simultaneously with an AR cDNA probe and a control cDNA probe from an unrelated gene. Finally, the pattern of inheritance of another X-linked DNA polymorphism allowed us to conclude that the original mutation had occurred in the germ line of the maternal great-grandfather of the index patient. Although rare, complete deletion of the AR gene is of particular importance in terms of correlation between molecular defect and phenotype, as it represents the quintessential form of complete androgen insensitivity, the null phenotype.     

Evolution of mouse immunoglobulin lambda genes.

The mouse has four C lambda and two V lambda genes. We have isolated Charon 4A clones that contain all six lambda genes from a BALB/c germ-line library. We present here the DNA sequences of the C lambda 2, C lambda 3, and C lambda 4 genes and also correct what are apparently errors in previous reports of C lambda 1 protein and DNA sequences. In addition, we have analyzed cloned DNAs by restriction mapping and electron microscopy to determine the relationships among the various lambda genes. By heteroduplex analysis, two gene clusters containing JC lambda 3--JC lambda 1 and JC lambda 2--JC lambda 4 show homology extending from the J regions 5' of C lambda 3/C lambda 2 to just 3' of C lambda 1/C lambda 4. Other than the region between the genes, very little homology exists in the C lambda flanking regions. In contrast, V lambda 1 and V lambda 2 genes show considerable homology extending into the 5' flanking regions. Large inverted repeats are found in the 5' flanking regions of V lambda 1 and C lambda 3, as well as in the 3' flanking regions of both C lambda gene clusters. DNA sequence divergences between the C lambda genes indicate that an ancestral JC lambda x--JC lambda g gene cluster arose at about the time of the first mammals by duplication of a primordial JC lambda gene. The data further suggest that the JC lambda x--JC lambda gene cluster duplicated after the speciation of mouse and man and subsequently diverged into the present day JC lambda 3--JC lambda 1 and JC lambda 2--JC lambda 4 gene clusters. C lambda 4, a pseudogene, became inactive at about the time of duplication of the ancestral JC lambda x--JC lambda y cluster. Comparison of DNA sequence divergence between the V lambda 1 and V lambda 2 genes demonstrates an anomaly. The percentage of amino acid replacement changes is approximately the same for V lambda 1/V lambda 2 as for C lambda 3/C lambda 2, implying that the ancestral V lambda gene was duplicated at the same time, and possibly together with, the JC lambda x--JC lambda y cluster. However, there are fewer silent changes than amino acid replacement changes between the V lambda 1/V lambda 2 genes, suggesting either that a selective pressure acted on the silent sites or that V lambda genes have only recently been duplicated. We also consider the possibility of a gene conversion event subsequent ot a more ancient duplication.     

Incidence of Pseudomonas aeruginosa bacteremia: a population-based study

Background

The incidence of Pseudomonas aeruginosa bacteremia has not been defined in a population-based investigation.

Methods

We performed a retrospective, population-based incidence study using resources of the Rochester Epidemiology Project of Olmsted County, Minnesota. We identified all Olmsted County residents with P. aeruginosa bacteremia between January 1, 1997, and December 31, 2006, by microbiology records in the only 2 laboratories in the county. Medical records were reviewed to confirm diagnosis, residency status, and clinical characteristics.

Results

Age-adjusted incidence per 100,000 person-years was 10.8 (95% confidence interval [CI], 7.5-14.0) in men and 3.7 (95% CI, 2.2-5.2) in women for total P. aeruginosa bacteremia, and 8.4 (95% CI, 5.5-11.2) in men and 2.5 (95% CI, 1.3-3.8) in women for monomicrobial P. aeruginosa bacteremia. There was no significant change in incidence of total P. aeruginosa bacteremia during the past decade (P = .418). Incidence increased exponentially with age, with a greater magnitude of increase in men compared with women for total and monomicrobial P. aeruginosa bacteremia (P = .007 and P = .015, respectively). In patients with monomicrobial P. aeruginosa bacteremia, the median age was 69 years, and 78.4% of cases were either nosocomial or health care associated. Most patients had multiple comorbid conditions. The urinary tract was the most common primary source of infection. The 28-day all-cause mortality of monomicrobial P. aeruginosa bacteremia was 25.5%. In vitro susceptibility to ciprofloxacin was 95.3%.

Conclusion

To our knowledge, this is the first population-based incidence study of P. aeruginosa bacteremia. The incidence of P. aeruginosa bacteremia has remained stable during the past decade. Fluoroquinolone susceptibility is high among local P. aeruginosa bacteremia isolates.     

Host defense and inflammatory gene polymorphisms are associated with outcomes after HLA-identical sibling bone marrow transplantation

We made the hypothesis that donor and recipient gene polymorphisms that drive the host response to microorganisms could be associated with infections after bone marrow transplantation (BMT). HLA-identical BMT was performed for patients with acute (n = 39) or chronic leukemia (n = 68). Genotyping was performed in 107 D/R DNA pairs for gene polymorphisms of cytokines (tumor necrosis factor-alpha [TNF-alpha] and TNF-beta, interleukin-1 receptor antagonist [IL-1Ra], IL-6, and IL-10), adhesion molecules (CD31 and CD54), Fcgammareceptors (FcgammaRIIa, IIIa, IIIb), mannose-binding lectin (MBL), and myeloperoxidase (MPO). First infection (overall) and first episodes of bacterial, viral, or invasive fungal infection were studied retrospectively for 180 days after BMT. Univariate and multivariate analyses, using death as a competing event, were performed to study risk factors. In multivariate analysis, first overall infections were increased in patients with the FcgammaRIIa R-131 genotype (hazard ratio [HR] = 1.92; P =.04), and severe bacterial infections were increased when the MPO donor genotype was AG or AA (HR = 2.16; P =.03). Viral and invasive fungal infections were not influenced by any genetic factor studied. Interestingly, we also found that (1) time to neutrophil recovery was shorter when donors were FcgammaRIIIb HNA-1a/HNA-1b (HR = 1.77; P =.002); (2) donor IL-1Ra (absence of IL-1RN*2) increased the risk for acute graft-versus-host disease (GVHD) (II-IV) (HR = 2.17; P =.017); and (3) recipient IL-10 (GG) and IL-1Ra genotypes increased the risk for chronic GVHD (P =.03 and P =.03, respectively). Finally, 180-day transplantation-related mortality rates were increased when donors were FcgammaRIIIb HNA-1a/HNA-1a or HNA-1b/HNA-1b (HR = 2.57; P =.05) and donor MPO genotype was AA (HR = 5.14; P =.004). In conclusion, donor and recipient gene polymorphisms are informative genetic risk factors for selecting donor/recipient pairs and could help in the understanding of mechanisms involved in host defenses of BM transplant recipients.     

A perspective on converting enzyme inhibitors and calcium channel antagonists in diabetic renal disease.

Hypertension and renal disease are major causes of morbidity and mortality in the diabetic population, with the presence of microalbuminuria established as a predictor of excess mortality. Numerous attempts, both pharmacologic and nonpharmacologic, have been made to intervene in the disease process. Experimental and clinical evidence suggests that the converting enzyme inhibitors and, more recently, certain calcium antagonists have beneficial effects on renal function above and beyond those simply due to blood pressure control. These effects are likely attributable to favorable systemic and renal hemodynamic changes as well as to direct cellular effects. However, intervention with these agents in various rat models of diabetes or hypertension is initiated very early. Hence, some of the beneficial renal effects may not be as dramatic in clinical practice because of the more commonly advanced stage seen at the time of intervention. We present an overview of the histologic, renal hemodynamic, and antiproteinuric effects of these agents in the experimental setting, as well as the clinical evidence supporting the use of angiotensin-converting enzyme inhibitors and certain classes of calcium antagonists in diabetic renal disease.     

Treatment with interleukin-3 plus granulocyte-macrophage colony- stimulating factors improves the selectivity of Ara-C in vitro against acute myeloid leukemia blasts

Hematopoietic growth factors (HGFs) interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) individually have been shown to increase the percentage of acute myeloid leukemia (AML) blasts in S phase and enhance the cytotoxic effects of Ara-C against these blasts in culture. We compared in vitro the effects of a combined treatment with GM-CSF (10 ng/mL) plus IL-3 (10 ng/mL) on the metabolism and cytotoxicity of Ara-C in normal bone marrow mononuclear cells (NBMMC) and AML blasts. NBMMC from six healthy volunteers and AML blasts from 10 patients were incubated for 20 hours with or without IL- 3 plus GM-CSF, followed by a concurrent treatment with Ara-C for 4 additional hours. Exposure to the HGFs and Ara-C produced significantly higher intracellular Ara-CTP levels as well as higher Ara-CTP/dCTP pool ratios in AML blasts as compared with NBMMC. Treatment with HGFs resulted in [3H] Ara-C DNA incorporation that was significantly higher in AML blasts versus NBMMC. This selective improvement of Ara-C metabolism in AML blasts was associated with an enhanced Ara-C-mediated leukemia colony-forming unit (CFU) growth inhibition. In contrast, exposure to HGFs resulted in an improved colony growth of normal CFU granulocyte-monocyte and CFU-granulocyte, erythroid, monocyte, megakaryocyte. These in vitro studies indicate that a combined treatment with IL-3 plus GM-CSF may improve the selectivity of Ara-C against AML blasts.     

Effect of abciximab on late adverse events in patients with diabetes mellitus undergoing stent implantation

Percutaneous coronary intervention (PCI) in patients with diabetes mellitus (DM) is associated with higher rates of adverse cardiac events. Recent data suggest that adverse events are reduced in DM after PCI using stents with abciximab. We performed a retrospective analysis of a prospective PCI registry for all patients with DM who underwent stent placement at the Mayo Clinic from 1995 to 1997 (n = 570), and divided them into 2 groups based on whether abciximab was administered. Characterization and comparison of the clinical and angiographic variables, procedural outcomes, and short- and long-term event rates between groups was performed. The baseline clinical characteristics of the groups were similar, but patients treated with abciximab were more likely to be men with a lower left ventricular ejection fraction. Patients treated with abciximab had more multivessel intervention, saphenous vein graft intervention, and thrombus before intervention. The 30-day mortality rate (0.6% vs 3.0%, p = 0.03) and repeat PCI (0% vs 1.1%, p = 0.03) was lower in patients treated with abciximab. The 30-day rates of bypass surgery, myocardial infarction (MI), and a composite of death, MI, and revascularization were similar. The 1-year event rates did not differ significantly between patients taking and not taking abciximab for the end points of death (8.9% vs 8.8%, p = 0.97), MI (13.3% vs 11.4%, p = 0.57), bypass surgery (10.3% vs 6.2%, p = 0.20), repeat PCI (14.7% vs 15.9%, p = 0.76), and a composite of death, MI, and revascularization (30.4% vs 26.7%, p = 0.43). After adjusting for baseline variables, abciximab did not influence the occurrence of late adverse events.     

Disparities in HIV treatment and physician attitudes about delaying protease inhibitors for nonadherent patients

BACKGROUND: Current HIV treatment guidelines recommend delaying antiretroviral therapy for nonadherent patients, which some fear may disproportionately affect certain populations and contribute to disparities in care. OBJECTIVES: To examine the relationship of physician's attitude toward prescribing protease inhibitors (PIs) to nonadherent patients with disparities in PI use and with health outcomes. DESIGN: Prospective cohort study. PATIENTS AND SETTING: A national probability sample of HIV-infected adults in the United States and their health care providers was surveyed between January 1996 and January 1998. We analyzed data on 1717 patients eligible for PI treatment and the 367 providers who cared for them. MEASUREMENTS: Providers' attitude toward prescribing PIs to nonadherent patients, time until patients' first receipt of PIs, mortality, and physical health status. MAIN RESULTS: Eighty-nine percent of providers agreed that patient adherence is important in their decision to prescribe PIs (Selective) while 11% disagreed (Nonselective). Patients who had a Selective provider received PIs later than those with a Nonselective provider (P =.05). Adjusting for patient demographics and health characteristics and provider demographics, HIV knowledge, and experience, Latinos, women, and poor patients received PIs later if their provider had a Selective attitude but as soon as others if their provider had a Nonselective attitude. African-American patients received PIs later than whites, irrespective of their providers' prescribing attitude. Patients with Selective providers had similar odds of mortality than those with Nonselective providers (odds ratio, 1.1; 95% confidence interval, 0.6 to 2.0), but had slightly worse adjusted physical health status at follow-up (49.1 vs 50.4, respectively; P =.04), after controlling for baseline physical health status and other patient and provider covariates. CONCLUSIONS: Most providers consider patient adherence an important factor in their decision to prescribe PIs. This attitude appears to account for the relatively later use of PI treatment among Latinos, women, and the poor. Given the rising HIV infection rates among minorities, women, and the poor, further investigation of this treatment strategy and its impact on HIV resistance and outcomes is warranted.     

A likely explanation for the J-curve of blood pressure cardiovascular risk

We prospectively tested in the combined original and offspring Framingham cohorts the hypothesis that the increase in cardiovascular disease (CVD) incidence at low diastolic blood pressure (BP) is largely confined to subjects with increased systolic BP and hence an increased pulse pressure. The 10-year risk of 951 nonfatal CVD events and 204 CVD deaths was estimated at diastolic pressures of <80, 80 to 90, and > or =90 mm Hg, according to concomitant systolic BP. An increasing tendency for a J-curve relation of CVD incidence to diastolic BP was observed with successive increments in accompanying systolic BP. In both genders, a statistically significant excess of CVD events was observed at a diastolic BP of <80 mm Hg only when accompanied by a systolic BP of >140 mm Hg that persisted after adjustment for age and associated CVD risk factors. Patients with this condition of isolated systolic hypertension have been shown to benefit from antihypertensive treatment.