Cytomegalovirus (CMV) resistance in patients with CMV retinitis and AIDS treated with oral or intravenous ganciclovir

Treatment of cytomegalovirus (CMV) retinitis with oral ganciclovir results in relatively low plasma concentrations of drug, which theoretically could cause more frequent viral resistance compared with intravenous (iv) ganciclovir. By use of a plaque-reduction assay to quantify phenotypic sensitivity to ganciclovir, virus isolates were studied from patients with CMV retinitis participating in four clinical trials of oral ganciclovir. Before treatment, 69% of patients were culture-positive but just 1.1% of patients yielded a resistant CMV, defined as a median inhibitory concentration (IC50) >6 microM. On treatment, the first resistant isolate was recovered at 50 days. Overall, 3.1% of patients receiving iv ganciclovir and 6. 5% of those taking oral ganciclovir shed resistant CMV (median ganciclovir exposures of 75 and 165 days, respectively). Since IC50s for clinical isolates increased proportionately with treatment duration, it is likely that viral resistance would be more frequent with longer treatment.

Strand displacement amplification and homogeneous real-time detection incorporated in a second-generation DNA probe system, BDProbeTecET

BACKGROUND

Amplified DNA probes provide powerful tools for the detection of infectious diseases, cancer, and genetic diseases. Commercially available amplification systems suffer from low throughput and require decontamination schemes, significant hands-on time, and specially trained laboratory staff. Our objective was to develop a DNA probe system to overcome these limitations.

METHODS

We developed a DNA probe system, the BDProbeTecTMET, based on simultaneous strand displacement amplification and real-time fluorescence detection. The system uses sealed microwells to minimize the release of amplicons to the environment. To avoid the need for specially trained labor, the system uses a simple workflow with predispensed reagent devices; a programmable, expandable-spacing pipettor; and the 96-microwell format. Amplification and detection time was 1 h, with potential throughput up to 564 patient results per shift. We tested 122 total patient specimens obtained from a family practice clinic with the BD ProbeTecET and the Abbott LCx(R) amplified system for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae.

RESULTS

Based on reportable results, the BDProbeTecET results for both organisms were 100% sensitive and 100% specific relative to the LCx.

CONCLUSIONS

The BDProbeTecET is an easy-to-use, high-throughput, closed amplification system for the detection of nucleic acid from C. trachomatis and N. gonorrhoeae and other organisms.

Antimicrobial resistance in gram-positive pathogens isolated in the UK between October 1996 and January 1997

Antimicrobial resistance in gram-positive pathogens from 30 centres in the UK (ten Teaching, ten Associate Teaching and ten District General Hospitals) was studied over a 4 month period between October 1996 and January 1997. High-level resistance (HLR) and low-level resistance (LLR) to penicillin amongst pneumococci was 3.3% and 3.4%, respectively. However, considerable variation in resistance rates was observed depending on geographical location (LLR range 0-15.4% and HLR range 0-30.8%). Considerable variation in resistance rates was also observed for Staphylococcus aureus to methicillin, with rates ranging from 0% to 56.7% depending on locality. Using conventional MIC methodology, none of the isolates of S. aureus was considered as having reduced sensitivity to vancomycin. However, eight isolates grew on Brain Heart Infusion Agar containing vancomycin (4 mg/L) after prolonged incubation and are therefore worthy of further investigation by electron microscopy. With Enterococcus faecalis, resistance rates were similar between the three types of hospital and only four isolates were considered resistant to glycopeptide antibiotics (one vanA and three vanB phenotype).

Medical packaging: more for less?

The market for medical devices is governed by the need to have validated products and processes, clean manufacturing environments and proven shelf-life. All this, often for products that are disposable, low-unit-cost items and, as such, highly price sensitive. This, in turn, has an impact on the businesses supplying the market. This article considers one such supply market, packaging, and the steps taken by packaging manufacturers to respond to these pressures while maintaining long-term, viable products.

Human corneal ablation threshold using the 193-nm ArF excimer laser

PURPOSE

To determine the human corneal threshold ablation energy density for the 193-nm ArF excimer laser, approximating clinical conditions.

METHODS

The VISX Star (Santa Clara, CA) 193-nm argon fluoride excimer laser was used to ablate the cornea in human eye bank eyes under clinical conditions. Corneas were exposed to energy densities of 10, 20, 30, 35, 40, 45, and 140 to 160 mJ/cm2. Corneas were fixed for light and transmission electron microscopy immediately after laser exposure.

RESULTS

Different ablation thresholds for various corneal structural elements were observed. The ablation threshold for the collagen in the corneal stroma was determined to be 30 mJ/cm2. Keratocytes had ablation thresholds of 40 mJ/cm2. These different ablation thresholds accounted for the production of stromal peaks and valleys, with the keratocytes atop the peaks.

CONCLUSIONS

Different corneal structural elements have different ablation threshold energy densities.

An in vitro comparison of the computerized tomography/CAD-CAM and direct bone impression techniques for subperiosteal implant model generation

Subperiosteal implants are currently fabricated by using the classic two-stage direct bone impression technique or by the use of the one-stage computer tomography/computer-assisted design-computer-assisted manufacture (CT/CAD-CAM) method. This study compares the accuracy of the two techniques by using cadaver maxillae and mandibles as the models for fabrication of casts. Seven cadaver jaw specimens were collected and subjected to direct bone impressions and to CT scans. Those derived from the direct bone impressions were poured in die stone, while the CT scans were sent for fabrication of CAD-CAM-generated casts. On each of the 14 models so produced, a cast grid was fabricated that was designed as a measuring device. The preciseness of fit of each grid was subjected to analyses that presented levels of accuracy. Statistical evaluation of these levels, reduced to numerical indices, revealed that the direct bone techniques resulted in acceptable castings in seven of seven cases, whereas the CAD-CAM method yielded adequate castings in five of seven cases.

Cytomegalovirus-specific IFNgamma and IL-4 are produced by antigen expanded human blood lymphocytes from seropositive volunteers

The cytokine responses to cytomegalovirus (CMV) antigen in seropositive and seronegative individuals were measured using a combination of antigenic expansion and intracellular staining. Intracellular IFNgamma and IL-4 were produced in a dose-dependent manner by T cells in response to CMV only in the seropositive population. The potential for individual cells to produce both Th1 and Th2 cytokines simultaneously was clear, as IL-4 was most often produced in those cells with the highest IFNgamma production. The cytokine-specific nature of this response was demonstrated by fluorescence microscopy, which showed granular cytoplasmic staining, and at the mRNA level by ribonuclease protection assays. These methods expand our ability to evaluate the immune response to CMV, and can now be correlated to a number of clinical conditions.

Interaction of insulin, glucagon-like peptide 1, gastric inhibitory polypeptide, and appetite in response to intraduodenal carbohydrate

The relation between gastrointestinal incretin hormones in the control of insulin release and short-term satiety by intestinal carbohydrate was investigated in 8 fasted, healthy male volunteers. Insulin, gastric inhibitory polypeptide (GIP), glucagon-like peptide 1 (GLP-1), and appetite ratings were measured during, and food intake was measured after, intraduodenal infusions of glucose or saline. Studies were conducted under hyperinsulinemic and euglycemic conditions. Raising plasma insulin with intravenous insulin infusion to concentrations slightly above usual postprandial concentrations (356.4 +/- 4.8 pmol/L) had no effect on GIP, GLP-1, or appetite ratings before the intraduodenal infusions began. Intraduodenal glucose infusion resulted in a further increase in plasma insulin to a peak of 779.4 +/- 114.0 pmol/L, caused an early increase in plasma GIP and a later increase in GLP-1 concentrations (P < 0.01), suppressed appetite (P < 0.05), and reduced energy intake (P < 0.01) compared with intraduodenal infusion of saline. There was a close association between the increase in GLP-1 and decrease in appetite. Infusion of octreotide to suppress the release of gastrointestinal hormones prevented the rise in insulin, GIP, and GLP-1 induced by intraduodenal glucose infusion and reversed the suppression of appetite and reduction in energy intake. These results suggest that 1) when infused to result in plasma concentrations slightly above usual postprandial concentrations, insulin does not inhibit its own release and 2) the effects of intraduodenal glucose on appetite may be mediated through the release of GLP-1 and not insulin.

Case notes, case histories, and the patient's experience of insanity at Gartnavel Royal Asylum, Glasgow, in the nineteenth century

This article is concerned primarily with questions as to how and why case notes were produced and utilized, and how they may (or may not) be used by historians. More specifically, it discusses how the Glasgow Royal Asylum's case notes may be deployed to access patients' experiences of madness and confinement. The deficiencies and biases of the case record are also explored. So too is the relationship of case notes with other asylum based records, including reception order questionnaires, with a separate section on patient writings as part of the case history corpus. This leads into an analysis of how the Asylum's case notes became case histories and for what purposes. These subjects are related to changes and continuities in medical ideologies about insanity, social attitudes to the insane and the nature of medical practice in asylums. Some fundamental shifts in emphasis in the use of the case note and case history occurred in this period. These shifts were associated with an increased emphasis on organic interpretations of mental disease and on clinical approaches to insanity; with the medicalization of asylum records and the wider discourse on insanity, and with declining deference to the public at large in the presentation of cases. The survey concludes by analysing the changing place of patient testimony within the case record.

Optimizing smoking cessation strategies

Smoking cigarettes remains the leading cause of preventable illnesses and premature deaths in the United States. Although approximately half of living Americans who have ever smoked have quit, recent studies show that more than 70% of current smokers would like to stop smoking. Health care providers can enhance smoking cessation in their clients by performing assessments of both the physical and psychologic addictive aspects of smoking as well as past and current cessation barriers. Based on the assessment, the clinician should formulate a treatment plan by individualizing appropriate education, counseling, motivation, and pharmacologic support. This article reviews the prevalence and hazards of smoking and supplies health care providers with interventions to assist clients in becoming and remaining nonsmokers.

Drosophila OVO zinc-finger protein regulates ovo and ovarian tumor target promoters

The ovo+ and ovarian tumor+ genes function in the germline sex determination pathway in Drosophila, but the hierarchical relationship between them is unknown. We found that increased ovo+ copy number resulted in increased ovarian tumor expression in the female germline and increased ovo expression in the male germline. The ovo locus encodes C2H2 zinc-finger proteins. Bacterially expressed OVO zinc-finger domain bound to multiple sites at or near the ovo and ovarian tumor promoters strongly suggesting that OVO is directly autoregulatory and that ovarian tumor is a direct downstream target of ovo in the germline sex determination hierarchy. Both positive and negative regulation by OVO proteins appears likely, depending on promoter context and on the sex of the fly. Our observation that two strong OVO-binding sites are at the initiator of the TATA-less ovo-B and ovarian tumor promoters raises the possibility that OVO proteins influence the nucleation of transcriptional pre-initiation complexes.

"Carving out" conditions from global capitation rates: protecting high-cost patients, physicians, and health plans in a managed care environment

The purposes of this study were (1) to develop a method for identifying individuals with high-cost medical conditions, (2) to determine the percentage of healthcare spending they represent, and (3) to explore policy implications of "carving out" their care from managed care capitation. Annual payments over a 2-year period to enrollees of three health plans--a traditional managed care organization, and a state Medicaid program--were determined by using a cross-sectional analysis of insurance claims data. The main outcome measures were the number of enrollees with total annual payments in excess of $25,000 and the contribution of these high-cost enrollees to each health plan's total costs. Forty-one groups of diagnosis and procedure codes representing a combination of acute and chronic conditions were included on the list of carve-out conditions. Pulmonary insufficiency and respiratory failure together accounted for the largest number of high-cost individuals in each health plan. Solid organ and bone marrow transplants, AIDS, and most malignancies that required high-dose chemotherapy were also important. The carve-out list identified more than one third of high-cost individuals enrolled in the Medicaid program, approximately 20% of high-cost managed care enrollees, and 10% of high-cost fee-for-service enrollees. These data confirm that it is possible to identify high-cost individuals in health plans by using a carve-out list. Carving out high-cost patients from capitation risk arrangements may protect patients, physicians, and managed care organizations.