An open-label trial of stavudine, lamivudine and efavirenz in the treatment of HIV-positive, treatment-naive patients, and implications for clinical practice

A phase II, open-label study of stavudine, lamivudine and efavirenz resulted in significant reductions in plasma HIV-1 RNA over a 24 week period in human immunodeficiency virus (HIV)-infected individuals. The trial currently has 68 patients, and this presentation covers data on the first 42 patients enrolled for 24 weeks. The mean plasma HIV-1 RNA on entry was 75858 HIV RNA copies/ml, and the mean CD4 count was 380 cells/mm3. After 24 weeks, the CD4 count increased by 169 cells/mm3 above baseline. plasma HIV-1 RNA was markedly reduced: at 24 weeks, more than 97% of patients had <50 HIV RNA copies/ml based on observed data, and 89% of patients had <50 copies/ml based on strict intent-to-treat analysis (non-completer=failure). The favourable interactions of these agents resulted in no discontinuations owing to adverse effects. This regimen provides an important first-line treatment for antiretroviral-naive patients.

Design for an accelerator-based orthogonal epithermal neutron beam for boron neutron capture therapy

This paper is concerned with the proposed Birmingham accelerator-based epithermal neutron beam for boron neutron capture therapy (BNCT). In particular, the option of producing a therapy beam at an orthogonal direction to the incoming protons is considered. Monte Carlo radiation transport simulations, both with and without a head phantom, have shown that an orthogonal beam geometry is not only acceptable but is indeed beneficial, in terms of a lower mean neutron energy and an enhanced therapeutic ratio for the same useful neutron fluence in the therapy beam. Typical treatment times for various beam options have been calculated, and range from 20 to 48 min with a 5 mA beam of 2.8 MeV protons, if the maximum photon-equivalent dose delivered to healthy tissue is to be 12.6 Gy Eq. The effects of proton beam diameter upon the therapy beam parameters have also been considered.

Tibial lead determination by99Tcmradiopharmaceutical X-ray fluorescence

The feasibility of measuring tibial lead concentration by x-ray fluorescence with an internal 99Tcm labelled bone-seeking radiopharmaceutical was investigated using phantoms containing known values of lead concentration and 99Tcm activity. The minimum detectable concentration (MDC) at two standard deviations based on the counts in the Kalpha1 peak of 10.9 microg Pb ml(-1) was estimated to correspond to an MDC for an individual within a range of approximately 8-15 microg Pb (g bone mineral)(-1) if the counts from all four K x-ray peaks were included. Due to its much greater dose compared to an external source, the MDC of this internal source technique would have to be reduced before it could be used for measurements of occupationally or environmentally exposed individuals other than as an adjunct for a patient undergoing a bone scan. Methods of achieving such a reduction include increasing the acquisition time and the number of HPGE detectors, and optimizing the design of their collimators.

Toward a final design for the Birmingham boron neutron capture therapy neutron beam

This paper is concerned with the proposed Birmingham accelerator-based epithermal neutron beam for boron neutron capture therapy (BNCT). Details of the final moderator design, such as beam delimiter, shield, and beam exit surface shape are considered. Monte Carlo radiation transport simulations with a head and body phantom have shown that a simple flat moderator beam exit surface is preferable to the previously envisioned spherical design. Dose rates to individual body organs during treatment have been calculated using a standard MIRD phantom. We have shown that a simple polyethylene shield, doped with natural lithium, is sufficient to provide adequate protection to the rest of the body during head irradiations. The effect upon the head phantom dose distributions of the use of such a shield to delimit the therapy beam has been evaluated.

Morphology comparison of individually selected hyperactivated and non-hyperactivated human spermatozoa

The objective of this study was to compare the morphology of human spermatozoa undergoing hyperactivated motility in vitro with those that were non-hyperactivated (non-hyp). Hyperactivation criteria were established by the Hobson Sperm Tracker (HST), sampling at 25 Hz, as curvilinear velocity (VCL) > or = 70 microns/s, amplitude of lateral head displacement (ALH) > or = 7 microns, linearity (LIN) < or = 30% and straight-line velocity (VSL) < or = 30 microns/s. Specially developed software incorporated in the HST produced a white computer-generated overlay for spermatozoa satisfying hyperactivation criteria. These spermatozoa, visually identified on a tracking monitor, were individually removed with micromanipulation equipment using a 12 microns-diameter needle. Fifty-six patient ejaculates were examined comprising a total morphological analysis of 1886 non-hyp spermatozoa and 1051 hyperactivated spermatozoa. Hyperactivated spermatozoa had a significantly higher mean percentage of normal heads and small acrosomes (P < 0.0001 and < 0.0001 respectively) and a significantly lower percentage of large and round heads, midpieces and tail defects (P = 0.002, < 0.0001, 0.02 and < 0.0001 respectively) when compared with non-hyp spermatozoa. These data demonstrate, for the first time, that a homogeneous live population of human hyperactivated spermatozoa, selected in vitro from patients with highly variable degrees of teratozoospermia, is comprised predominantly of cells with normal morphology (P < 0.0001).

Performance assessment of patient dosimetry services and X-ray quality assurance instruments used in diagnostic radiology

Experiences of the Regional Radiation Physics and Protection Service (RRPPS) in performance assessment of diagnostic X-ray QA instrumentation and on-patient dosemeters are recounted. Issues relating to the provision of realistic and reproducible reference conditions for calibrated X-irradiations are considered and summary statistics from test measurements of dose and kVp meters are provided. For both dose and kVp meters it is indicated that as many as 25% of instruments used in routine use in the U.K. may require some adjustment before they can truly be said to be performing as the manufacturer intended. Results from intercomparison exercises for patient dosimetry services are also discussed. It is apparent that, for those centres participating in the exercise, dose assessments are generally being obtained to within a bias and a relative standard deviation of less then 10%.

Assessment of human CD4+ and CD8+ T lymphocyte responses in experimental viral vaccine studies

The traditional in vitro correlate of immunological protection is the induction by a vaccine of neutralizing antibodies against the virus. It was formerly assumed that protection induced by a vaccine was solely due to neutralizing antibodies. Neutralizing antibodies are potent in the prevention of certain diseases, but virus-specific CD4+ T helper cells aid in the proliferation of specific antigen-triggered B cells to make antibodies. CD8+ T cells are responsible for eliminating virus-infected cells during viral illness, and may act as a second line of defence by becoming activated and eliminating any cells that become infected despite the presence of neutralizing antibodies, for example because of a large challenge dose or antigenic variation at the antibody combining sites. We will briefly review our approaches for measuring human virus-specific CD4+ and CD8+ T cell responses to experimental vaccines. It is critically important to have sensitive, quality controlled assays, including positive controls. There are many potential variables in human T cell assays and pitfalls, which usually result in negative CTL results. Uninterpretable data are to be expected unless adequate preliminary testing has been done to establish sensitive, specific and controlled human antigen specific CD4+ and CD8+ T cell assays.

In-phantom neutron fluence measurements in the orthogonal Birmingham boron neutron capture therapy beam

This paper presents the results of an experimental investigation into the performance of the Birmingham accelerator-based epithermal BNCT beam. In-phantom gold foil activation and boron trifluoride tube measurements have been used. The results have been compared with calculated response rates using Monte Carlo modeling of the entire neutron system from source to phantom and detector. The excellent agreement obtained gives us confidence in the validity of the simulations and our ability to predict accurately the neutronic performance of our BNCT facility.

The case history of an elite ultra-endurance cyclist who developed chronic fatigue syndrome

An elite ultra-endurance athlete, who had previously undergone physiological and performance testing, developed chronic fatigue syndrome (CFS). An incremental cycling exercise test conducted while he was suffering from CFS indicated decreases in maximum workload achieved (Wmax; -11.3%), the maximum oxygen uptake (VO2max; -12.5%), and the anaerobic threshold (AT; -14.3%) compared to pre-CFS data. A third test conducted after the athlete had shown indications of significant improvement in his clinical condition revealed further decreases in Wmax (-7.9%), VO2max (-10.2%) and AT (-8.3%). These data, along with submaximal exercise data and muscle biopsy electron microscopic analyses, suggest that the performance decrements were the result of detraining, rather than an impairment of aerobic metabolism due to CFS per se. These data may be indicative of central, possibly neurological, factors influencing fatigue perception in CFS sufferers.

Identification of the lectin-like receptor for oxidized low-density lipoprotein in human macrophages and its potential role as a scavenger receptor

A new receptor for oxidized low-density lipoprotein (LDL), lectin-like oxidized LDL receptor-1 (LOX-1), has recently been cloned from bovine endothelial cells and human lung. A limited tissue-distribution study suggested that the protein was mainly produced by the vascular endothelium. In the present study we demonstrate that LOX-1 is also expressed in macrophages, where it may function as a scavenger receptor. LOX-1 was not detected in undifferentiated THP-1 cells or in freshly isolated human blood monocytes. However, mature human monocyte-derived macrophages and differentiated THP-1 cells showed high levels of LOX-1 transcripts. Consistent with these results, immunofluorescence staining and FACS analysis demonstrated that LOX-1 protein is expressed on the plasma membrane of macrophages. Western-blot analysis of membranes from macrophages (but not those from monocytes) identified a single band, with an apparent molecular mass of about 40 kDa, that displayed oxidized LDL-binding activity. These results suggest that differentiation induces the expression of LOX-1 in macrophages, where it may play a role as a scavenger receptor and/or a receptor for oxidized LDL.

Microplate-reverse hybridization method to determine dengue virus serotype

A reverse transcriptase-polymerase chain reaction (RT-PCR) and microplate-reverse hybridization method were developed to detect and type dengue viruses in patients plasma specimens. A silica method was used to isolate RNA; and 3'-noncoding region universal primers were used to amplify dengue virus RNA. Using RT-PCR and ethidium bromide staining we could detect dengue virus in serum spiked with serially diluted dengue virus with a level of sensitivity similar to that of a quantitative fluorescent focus assay of dengue viruses in cell culture, i.e. 1.4 fluorescent focus units per reaction. Applying this assay to 14 dengue-positive plasma samples and 13 dengue-negative samples, dengue viremia was detectable by RT-PCR with a sensitivity comparable to mosquito inoculation. To determine the serotypes, digoxigenin-labeled PCR products from plasma samples and six laboratory adapted dengue viruses were hybridized in stringent conditions to serotype-specific DNA probes immobilized on microplates, and the hybridized product was detected with a colorimetric assay. Serotypes of dengue viruses, in cell culture and in patient plasma specimens, were identified using this method.

Changes in performance, muscle metabolites, enzymes and fibre types after short sprint training

In contrast to endurance training, little research has been carried out to investigate the effects of short (< 10 s) sprint training on performance, muscle metabolism and fibre types. Nine fit male subjects performed a mean of 16 outdoor sprint running training sessions over 6 weeks. Distances sprinted were 30-80 m at 90-100% maximum speed and between 20 and 40 sprints were performed in each session. Endurance (maximal oxygen consumption; VO2max), sprint (10 m and 40 m times), sustained sprint (supramaximal treadmill run) and repeated sprint (6 x 40 m sprints, 24 s recovery between each) performance tests were performed before and after training. Muscle biopsy samples (vastus lateralis) were also taken to examine changes in metabolites, enzyme activities and fibre types. After training, significant improvements were seen in 40 m time (P < 0.01), supramaximal treadmill run time (P < 0.05), repeated sprint performance (P < 0.05) and VO2max (P < 0.01). Resting muscle concentrations of ATP and phosphocreatine did not change. Phosphorylase activity increased (P < 0.025), citrate synthase activity decreased (P < 0.01), but no significant changes were recorded in myokinase and phosphofructokinase activities. The proportion of type II muscle fibres increased significantly (P < 0.05). These results demonstrate that 6 weeks of short sprint training can improve endurance, sprint and repeated sprint ability in fit subjects. Increases in the proportion of type II muscle fibres are also possible with this type of training.

Hypothermia reduces neurologic deficits associated with placement of a vascular prosthesis in the abdominal aorta of rabbits

Treatment for atherosclerotic vascular disease in human beings ranges from medical management to interventional therapy, such as angioplasty, atherectomy, and bypass grafting. Recently, bypass grafting with a vascular prosthesis has received increased attention and clinical use. In the course of studies to optimize use of a small-caliber vascular prosthesis, five of six rabbits undergoing implantation of a polytetrafluoroethylene vascular prosthesis in the infrarenal abdominal aorta developed hind limb neurologic deficits, which resulted from focal ischemic damage to the spinal cord attributable to temporary vascular occlusion of the abdominal aorta during placement of the vascular prosthesis. In subsequent studies, induction of systemic hypothermia decreased the rate of development of neurologic deficits from 83 to 9% without any apparent perioperative complications associated with decreased body temperature. We determined that mild hypothermia (rectal temperature of 32 to 35 degrees C), combined with aortic occlusion time of < 40 min, is sufficient to afford protection from ischemic injury to the spinal cord in the rabbit.

Knowledge of and attitude toward patient confidentiality within three family medicine teaching units

PURPOSE

To describe the knowledge and attitudes about confidentiality issues within family medicine teaching units (FMUs) at McGill University.

METHOD

The authors surveyed McGill University FMU staff (physicians, nurses, and support staff) on their knowledge of and attitudes toward confidentiality issues.

RESULTS

The response rate was 84%. Only one of nine questions on confidentiality laws was correctly answered by more than 80% of the respondents. Only 55% of the support staff knew that police are not permitted free access to charts, although the majority of those who answered incorrectly held attitudes that were consistent with the law. Only approximately 25% knew that physicians and nurses are not permitted free access to any medical record within the center. There were minimal differences between the professions or between the FMUs.

CONCLUSION

These findings suggest that FMU staff do not fully understand their obligations towards patient confidentiality.

Minimally oxidized low-density lipoprotein increases expression of scavenger receptor A, CD36, and macrosialin in resident mouse peritoneal macrophages

Fully oxidized LDL (OxLDL) is believed to contribute to atherogenesis in part by virtue of uptake into macrophages via specific scavenger receptors. This phenomenon results in the formation of cholesterol-loaded foam cells, a major component of atherosclerotic lesions. The present study is directed at examining the effects of OxLDL and minimally oxidized LDL (MM-LDL) on scavenger receptor expression and activity in mouse peritoneal resident macrophages. Macrophages were preincubated with MM-LDL or OxLDL at concentrations of 25 or 50 microg/mL for 24 to 48 hours, after which their ability to bind and take up 125I-OxLDL or 125I-acetylated LDL (AcLDL) was determined. MM-LDL pretreatment induced a clear increase of cell association and degradation of 125I-OxLDL and 125I-AcLDL. Pretreatment with OxLDL also enhanced scavenger receptor activity, but to a lesser degree. Neither native LDL nor AcLDL had any effect. Scatchard analysis showed that preincubation with 50 microg/mL MM-LDL for 48 hours increased the Bmax of 125I-OxLDL and 125I-AcLDL by 139% and 154%, respectively, without significantly changing their affinity. Lipids extracted from MM-LDL also significantly induced scavenger receptor activity, but to a lesser extent than did intact MM-LDL. MM-LDL pretreatment increased both mRNA levels and protein levels of scavenger receptor A, CD36, and macrosialin. On the other hand, OxLDL pretreatment increased expression of macrosialin only. These results, showing that MM-LDL can upregulate scavenger receptor expression in mouse resident peritoneal macrophages, suggest that clearance of OxLDL by macrophages in lesions is more effective, in part because the OxLDL precursor, MM-LDL, primes the macrophage for foam cell generation.

Can we justify spermatid microinjection for severe male factor infertility?

During 1995 and 1996 the first spermatid pregnancies were announced with both round spermatid (ROSI) and elongated spermatid (ELSI) injections. These publications were flanked by live births from ROSI in a number of animal species, with resulting offspring appearing normal, healthy and fertile. However, the live births in humans heralded a scientific and ethical debate on the clinical use of this technology; and in a number of countries nationwide moratoria prohibiting spermatid microinjection were enjoined. Concerns surrounded the biological condition of spermatids and clinical implications of utilizing an immature spermatozoon for conception. Nevertheless, case reports and a few scientific studies on human spermatid conception have been published in recent years, and further polemic on testicular histopathology and prognosis has ensued. This paper reviews the current arguments on the clinical use of ROSI and ELSI, and evaluates the biology of the main contributory components of a spermatozoon to the subsequent embryo, namely the genetic material, the microtubular organizing complex and the putative oocyte activating factor. We also consider the relevant testicular histopathology and likely outcome in the context of the current birth rate from ROSI and ICSI. We conclude by considering the way forward for infertile men who require this technology to become genetic fathers, and whether the time is now appropriate to consider clinical trials.

Heat shock proteins hsp27 and hsp70: lack of correlation with response to tamoxifen and clinical course of disease in estrogen receptor-positive metastatic breast cancer (a Southwest Oncology Group Study)

In this study, we tested the hypothesis that heat shock proteins (hsps) 27 and 70 are associated with clinical resistance to tamoxifen. hsp27 is, like progesterone receptor, an estrogen-regulated protein. hsp70 is also of interest because of its interaction with estrogen receptors and because hsp70 is a component of the molecular chaperone machinery functioning in the assembly and trafficking of steroid receptors. In addition, hsps in general help protect cells against noxious stimuli and stress, and their expression has been linked to drug resistance. The study involved 205 tumors from estrogen receptor-positive tamoxifen-treated breast cancer patients with metastatic disease. All patients received daily tamoxifen as initial therapy for metastatic disease. The study began in 1982, and follow-up is now 9 years. hsp27 and hsp70 were detected by immunohistochemistry and scored according to the nuclear and/or cytoplasmic content. Expression of hsp27 or hsp70 was unrelated to estrogen receptor content, progesterone receptor content, menopausal status, age, and presence of visceral disease. Cytoplasmic and nuclear hsp27 positivities were weakly and inversely related to each other (P = 0.05). There was a significant association between cytoplasmic hsp27 and cytoplasmic hsp70 content (P < 0.001), as well as between nuclear hsp70 and nuclear hsp27 content (P = 0.001). Cytoplasmic and nuclear hsp70 were also associated (P = 0.02). However, increased hsp27 and hsp70 expression (nuclear or cytoplasmic) was not significantly associated with response to tamoxifen, time to treatment failure, or survival. Thus, this study clarifies the lack of clinical utility of hsp27 and hsp70 in predicting the response to tamoxifen in an estrogen receptor-positive breast cancer population.

Longitudinal measurements of the cadmium burden of 'jig solderers' using IVNAA

The liver and kidney cadmium burdens of a population of 10 'jig solderers' were measured in 1983 and 1995 using similar IVNAA measuring systems. Cadmium exposure ceased in 1985. No significant variation in kidney content was observed. The mean body burden had fallen by 18%, due to a decrease of mean liver content of 35%.

Predominance of HLA-restricted cytotoxic T-lymphocyte responses to serotype-cross-reactive epitopes on nonstructural proteins following natural secondary dengue virus infection

We examined the memory cytotoxic T-lymphocytic (CTL) responses of peripheral blood mononuclear cells (PBMC) obtained from patients in Thailand 12 months after natural symptomatic secondary dengue virus infection. In all four patients analyzed, CTLs were detected in bulk culture PBMC against nonstructural dengue virus proteins. Numerous CD4+ and CD8+ CTL lines were generated from the bulk cultures of two patients, KPP94-037 and KPP94-024, which were specific for NS1.2a (NS1 and NS2a collectively) and NS3 proteins, respectively. All CTL lines derived from both patients were cross-reactive with other serotypes of dengue virus. The CD8+ NS1.2a-specific lines from patient KPP94-037 were HLA B57 restricted, and the CD8+ NS3-specific lines from patient KPP94-024 were HLA B7 restricted. The CD4+ CTL lines from patient KPP94-037 were HLA DR7 restricted. A majority of the CD8+ CTLs isolated from patient KPP94-024 were found to recognize amino acids 221 to 232 on NS3. These results demonstrate that in Thai patients after symptomatic secondary natural dengue infections, CTLs are mainly directed against nonstructural proteins and are broadly cross-reactive.

Correlation between intracellular cAMP content, kinematic parameters and hyperactivation of human spermatozoa after incubation with pentoxifylline

Various compounds have been used in the attempt to improve sperm motility, including pentoxifylline (PF), a methylxanthine derivative. It has been postulated that PF, being a phosphodiesterase inhibitor, increases sperm kinematic parameters and the number of spermatozoa exhibiting hyperactivated motility by raising the intracellular content of cAMP, a molecule involved in the generation of sperm energy. However, it has not been clarified whether the biological effects of PF on sperm motility correlate with its ability to increase intracellular cAMP levels. To examine this relationship, the kinematic parameters, hyperactivation, and intracellular cAMP content were evaluated in motile spermatozoa, obtained by discontinuous Percoll gradient and swim-up from 21 normozoospermic semen samples, incubated without and with PF for 0, 1, 2, and 4 h. PF increased beat cross frequency after 1 and 2 h of incubation, curvilinear velocity and lateral head displacement (ALH) after 4 h, and hyperactivation after 1, 2, and 4 h, and decreased linearity (LIN) after 1 h of incubation. The intracellular cAMP content of spermatozoa incubated with PF increased at all time-points examined. Both intracellular cAMP content and increase in hyperactivation in response to PF decreased with the length of incubation. In the absence of PF, cAMP content was unchanged and was correlated significantly only with ALH and the percentage of spermatozoa with hyperactivated motility. Following incubation with PF, cAMP content correlated with hyperactivation and all sperm kinematic parameters, with the exception of LIN and straightness. These findings suggest that the beneficial effects of PF on sperm kinematic parameters and hyperactivation are related to its ability to increase intracellular cAMP content.