Development of a novel, rapid processing protocol for polymerase chain reaction-based detection of bacterial infections in synovial fluids

We describe the development of a molecular detection system designed for use with synovial fluid (SF)-based infections. The methodology employs a lysis/extraction procedure that effectively disrupts microorganisms allowing for release of the microbial DNA and its amplification by polymerase chain reaction (PCR). We tested the effectiveness of adding a mixed-bed, ion-exchange resin to the extract to remove PCR inhibitory components present in the SF. After centrifugation to separate the resin, DNA contained in the supernatant is subjected to PCR using oligonucleotide primers designed for broad-spectrum microorganism detection. Amplification products are analyzed by agarose gel electrophoresis and/or DNA hybridization methodology. We report here the detection sensitivity and specificity of the protocol using SF inoculated with Escherichia coli and Staphyloccocus aureus. We have applied this new methodology to clinical SF specimens with results superior to standard laboratory culturing assays.     

Influence of gender and the endocrine environment on the distribution of androgen receptors in the lacrimal gland

Androgens are known to regulate both the structure and function of lacrimal tissue in a variety of species. To explore the endocrine basis for this hormone action, the following study was designed to: (1) determine the cellular distribution of androgen receptors in the lacrimal gland; and (2) examine the influence of gender and the endocrine environment on the glandular content of these binding sites. Lacrimal glands were obtained from intact, castrated, hypophysectomized, diabetic or sham-operated male or female adult rats, mice or hamsters, as well as from orchiectomized rats exposed to placebo compounds or physiological levels of testosterone. The cellular location of androgen receptors was evaluated by utilizing an immunoperoxidase protocol, in which a purified rabbit polyclonal antibody to the rat androgen receptor was used as the first antibody. Our findings with lacrimal glands showed that: (1) androgen receptors are located almost exclusively in nuclei of epithelial cells; (2) the cellular distribution or intranuclear density of these binding sites is far more extensive in glands of males, as compared to females; (3) orchiectomy or hypophysectomy, but not sham-surgery or diabetes, lead to a dramatic reduction in the immunocytochemical expression of androgen receptors; and (4) testosterone administration to orchiectomized rats induces a marked increase in androgen receptor content, relative to that in placebo-exposed glands. Our results also reveal that a 10 kb androgen receptor mRNA exists in the rat lacrimal gland. Overall, these findings demonstrate that gender and the endocrine system may significantly influence the distribution of androgen binding sites in rat lacrimal tissue. Moreover, our results show that androgens up-regulate their own lacrimal gland receptors.     

A chromatic-cancellation property of human pupillary responses

The pupil exhibits a response property somewhat analogous to perceptual red-green cancellation. Across a limited range of flash intensities near threshold, pupillary constrictions evoked by red flashes can be reduced, if not nulled, by the simultaneous addition of a green flash. The percentage of trials on which a stimulus-evoked response can be correctly discriminated from noise also falls to chance level as a green flash is added to the red flash. In terms of the quanta absorbed by L and M cones, the cancellation can be modelled as a function of magnitude of 0.65*L-M.     

Regeneration of a transplanted liver after right hepatic lobectomy

Liver regeneration has been described after heterotopic liver transplantation, small-for-size orthotopic liver transplantation and reduced-size liver transplantation. In this report, we document the regenerative response of a whole liver transplant to major resection for the first time. A right hepatic lobectomy for liver ischemia was performed in a 30-year-old female after transplantation for autoimmune disease of the liver. Volumetric analysis of computed tomography (CT) scans revealed a preoperative liver volume of 1,961 mL, whereas analysis of the 6-week posthepatectomy CT scan showed a volume of 1,820 mL. Factors influencing regeneration in the setting of a liver transplant include rejection, ischemia/thrombosis, infection, or cyclosporine hepatotrophic/hepatotoxic effects. These factors, balanced with the intrinsic ability of hepatocytes to achieve a standard liver volume, determine the extent of regeneration.     

Development of endometrial cancer in women on estrogen and progestin hormone replacement therapy

The presenting symptoms, hormonal regimens, treatment modalities, tumor pathology, and follow-up of 25 women developing endometrial cancer while receiving postmenopausal estrogen and progestin therapy were investigated retrospectively. Patients were interviewed and hormone therapies were confirmed through medical records. Pathology specimens were reviewed. Patients received conjugated estrogens (n = 20) or another estrogen (n = 5). For those on conjugated estrogens, the mean daily dose was 0.68 mg, monthly duration was 24.9 days, and monthly dose was 17.0 mg. Women also received medroxyprogesterone acetate (n = 23) or norethindrone acetate (n = 2). The most common regimen was sequential medroxyprogesterone acetate, at a mean daily dose of 7.5 mg, monthly duration of 9.3 days, and monthly dose of 68 mg (mean duration = 5.7 years). Most tumors were low stage and grade, with few demonstrating grade 3 disease (n = 2) or greater than 50% myometrial invasion (n = 2). Twenty-three (92%) had disease limited to the uterus, while two had stage IIIA disease. All are alive and disease-free after a median follow-up of 26 months. Estrogen and progestin therapy does not prevent endometrial cancer in all patients. Women who developed this tumor on sequential therapy in general received less than the recommended guidelines for daily dosage and monthly duration of progestin. Most patients had early-stage and low-grade disease. Continued vigilance in the care of women on hormone replacement therapy is necessary even when combination therapy is prescribed.     

Gordon Holmes, the cortical retina, and the wounds of war. The seventh Charles B. Snyder Lecture

By the turn of the 20th century, localization of function in the cerebral cortex of the brain had advanced considerably, but a relatively vague idea only existed that human vision was represented in the vicinity of the calcarine cortex. World War I produced a large number of isolated missile wounds of the brain. Their study yielded a complete topographical mapping of the visual field in the primary cortical vision center, and is a basis of our modern interpretation of visual fields. This map has been recently modified by MRI studies to show that the magnification of the central retinal projection onto the cerebral cortex to be even greater than previously thought. Many names are associated with the story of how war led to this knowledge. This essay refers to Harvey Cushing, William Osler, Tatsui Inouye, and most particularly to the career and contributions of the British neurologist Gordon Holmes.     

DNA damage and cell cycle checkpoints

DNA is prone to numerous forms of damage that can injure cells and impair fitness. Cells have evolved an array of mechanisms to repair these injuries. Proliferating cells are especially vulnerable to DNA damage due to the added demands of cellular growth and division. Cell cycle checkpoints represent integral components of DNA repair that coordinate cooperation between the machinery of the cell cycle and several biochemical pathways that respond to damage and restore DNA structure. By delaying progression through the cell cycle, checkpoints provide more time for repair before the critical phases of DNA replication, when the genome is replicated, and of mitosis, when the genome is segregated. Loss or attenuation of checkpoint function may increase spontaneous and induced gene mutations and chromosomal aberrations by reducing the efficiency of DNA repair. Defects in checkpoint control have been seen in certain hereditary cancer syndromes and at early stages of cell transformation. Mutations in checkpoint control genes therefore may contribute to the genetic instability that appears to drive neoplastic evolution.     

Gaucher disease: recommendations on diagnosis, evaluation, and monitoring

BACKGROUND: Timely diagnosis and continued monitoring of patients with type I Gaucher disease is critical because skeletal involvement can permanently disable patients and visceral organ involvement can lead to abdominal pain and secondary hematologic and biochemical complications. OBJECTIVE: To seek clinical consensus for minimum recommendations for effective diagnosis and monitoring of patients with type I Gaucher disease. PARTICIPANTS, EVIDENCE, AND CONSENSUS PROCESS: Contributing authors collaborated in quarterly meetings over a 2-year period to synthesize recommendations from peer-reviewed publications and their own medical experiences. These physicians care for most patients with Gaucher disease in the United States and serve as the US Regional Coordinators for the International Collaborative Gaucher Group Registry, the world's largest database for this disorder. CONCLUSIONS: The definitive method of diagnosis is enzyme assay of beta-glucocerebrosidase activity. Schedules differ for monitoring complications of type I Gaucher disease, depending on symptoms and whether enzyme replacement therapy is used. Hematologic and biochemical involvement should be assessed by complete blood cell count, including platelets, acid phosphatase, and liver enzymes, at baseline and every 12 months in untreated patients and every 3 months and at enzyme replacement therapy changes in treated patients. Visceral involvement should be assessed at diagnosis using magnetic resonance imaging or computed tomographic scans. Skeletal involvement should be assessed at diagnosis using T1- and T2-weighted magnetic resonance imaging of the entire femora and plain radiography of the femora, spine, and symptomatic sites. Follow-up skeletal and visceral assessments are recommended every 12 to 24 months in untreated patients, and every 12 months and at enzyme replacement therapy changes in treated patients.