Death due to sickle cell crisis: a case report

Sickle cell disease (SCD) is the most common hereditary hemoglobinopathy worldwide. It results in characteristic acute and chronic findings on postmortem computed tomography (PMCT), macroscopic and microscopic examinations. While the diagnostic imaging and macroscopic features are not specific for SCD on their own, when coupled with microscopic features such as sickled erythrocytes and evidence of chronic venous congestion (i.e., Gamna-Gandy bodies), these clues can help alert forensic pathologists to the presence of SCD. Despite the prevalence of the disease and the constellation of findings alluded to above, SCD is not often explored in forensic pathology literature. This case demonstrates classic acute and chronic features of SCD on PMCT, macroscopic and microscopic examinations. It explores the pathophysiology leading to sudden and unexpected death in a person with SCD and possible pitfalls in attribution of cause of death.

Ankle proprioception in children with cerebral palsy

PURPOSE

There is no established clinical standard to evaluate ankle proprioception in children with cerebral palsy (CP). This study compared ankle position sense of children with CP to age-matched children who are typically developing (TD).

METHODS

Children aged 6-17 years participated (15 CP, 58 TD). Using a custom-built device, the ankle was passively rotated to two positions for 25 trials. Using a psychophysical forced-choice paradigm, participants indicated which position was more plantarflexed. A psychometric function was fitted to the response data to determine the just noticeable difference (JND) threshold and the associated uncertainty (random error) for ankle position sense.

RESULTS

Median JND thresholds for the CP group were elevated (CP: 4.3°, TD: 3.0°). Three children with CP exceeded the 95th percentile of TD. No differences in random error were found.

CONCLUSION

This method assessed ankle proprioception relative to norm data and identified position sense impairments in children with CP. Using this method can provide data on proprioceptive status in CP, augmenting the assessment of motor impairment.

Delta radiomics analysis of Magnetic Resonance guided radiotherapy imaging data can enable treatment response prediction in pancreatic cancer

Background

Magnetic Resonance Image guided Stereotactic body radiotherapy (MRgRT) is an emerging technology that is increasingly used in treatment of visceral cancers, such as pancreatic adenocarcinoma (PDAC). Given the variable response rates and short progression times of PDAC, there is an unmet clinical need for a method to assess early RT response that may allow better prescription personalization. We hypothesize that quantitative image feature analysis (radiomics) of the longitudinal MR scans acquired before and during MRgRT may be used to extract information related to early treatment response.

Methods

Histogram and texture radiomic features (n = 73) were extracted from the Gross Tumor Volume (GTV) in 0.35T MRgRT scans of 26 locally advanced and borderline resectable PDAC patients treated with 50 Gy RT in 5 fractions. Feature ratios between first (F1) and last (F5) fraction scan were correlated with progression free survival (PFS). Feature stability was assessed through region of interest (ROI) perturbation.

Results

Linear normalization of image intensity to median kidney value showed improved reproducibility of feature quantification. Histogram skewness change during treatment showed significant association with PFS (p = 0.005, HR = 2.75), offering a potential predictive biomarker of RT response. Stability analyses revealed a wide distribution of feature sensitivities to ROI delineation and was able to identify features that were robust to variability in contouring.

Conclusions

This study presents a proof-of-concept for the use of quantitative image analysis in MRgRT for treatment response prediction and providing an analysis pipeline that can be utilized in future MRgRT radiomic studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01957-5.

Influence of the level of arterial resection on the replanting and revascularization results in hand surgery: prospective study over 22 months

The objective of this work was to assess whether the injury mechanisms are responsible for histological arterial lesions. This prospective single-center study included adults with wrist or hand arterial injury. Arterial resection of at least 2 mm from the proximal and distal stumps was performed before the arterial anastomosis. Histological analysis of the arterial stumps was performed. An ultrasound was performed 1 month postoperatively to check arterial patency. A clinical and functional evaluation was done at 1 month postoperative, then every 3 months. From 2018 to 2020, 46 patients were included with a maximum follow-up of 13 months. There were 35 cuts, 2 crush injuries, 8 amputation and 1 blast injury. Macroscopically, 37% of the margins were considered damaged. Histological analysis showed significant damage in 59% of the sections (27 out of 46 patients) with 50% for crush injury, 55% for cuts by mechanical tool, 62% for cuts by power tool, 62% for amputations and 100% for blasts. The failure rate was 9%: 2 replantations and 2 asymptomatic thromboses diagnosed by ultrasound. Postoperative pain on VAS was 1.75/10, range of motion was 87%, Quick DASH was 8%, SF36 PCS was 69% and SF36 MCS was 70%. Factors influencing the success or failure of anastomosis were the mechanism of injury (p = 0.02), associated nerve damage (p = 0.014) and length of proximal arterial cut (p = 0.046). Histological arterial lesions seem to correlate with the injury mechanism. Cuts caused by glass or crush injuries do not seem to require arterial resections of more than 2 mm. A continuation of the study with a larger number of subjects may generate statistically significant results.

Oral sedation in dentistry: evaluation of professional practice of oral hydroxyzine in the University Hospital of Rennes, France

PURPOSE

Management of a child's anxiety early in their treatment is essential in dentistry. Sedative medications are used to overcome increased anxiety from previous appointments and to promote the cooperation of children during treatment. Hydroxyzine is currently prescribed to young patients as part of the first level of conscious sedation. The main objective was to evaluate the professional practice of oral hydroxyzine, when prescribed for children presenting anxiety during dental treatment procedure performed by students and senior practitioners.

METHODS

A retrospective study of dental records and questionnaires was conducted at the Dental Care Centre of the University Hospital of Rennes, France. Parameters related to the prescription of hydroxyzine in children were evaluated as potential predictors of the dental session success, with adjustments on potential confounders.

RESULTS

The therapeutic outcome was very encouraging with 78.3% of success during dental sessions under sedation with oral hydroxyzine. Anxiety levels before the dental procedure and the medication compliance of the child were the main predictors of success. On the other hand, lower age (< 6 years old) and longer treatments (such as pulpotomy) worsened the outcome.

CONCLUSIONS

Careful analysis of the literature and results of this work showed the safety of hydroxyzine within the maximum dose authorized without adverse effects, compared to other molecules described and commonly used in dentistry. No adverse effects during dental procedure were noted. This allows for minimal sedation with efficiency for the great majority of pediatric treatment. This solution should be the first step in sedation to help practicing clinicians.

Nitrogen futures in the shared socioeconomic pathways 4

Humanity's transformation of the nitrogen cycle has major consequences for ecosystems, climate and human health, making it one of the key environmental issues of our time. Understanding how trends could evolve over the course of the 21st century is crucial for scientists and decision-makers from local to global scales. Scenario analysis is the primary tool for doing so, and has been applied across all major environmental issues, including nitrogen pollution. However, to date most scenario efforts addressing nitrogen flows have either taken a narrow approach, focusing on a singular impact or sector, or have not been integrated within a broader scenario framework - a missed opportunity given the multiple environmental and socio-economic impacts that nitrogen pollution exacerbates. Capitalizing on our expanding knowledge of nitrogen flows, this study introduces a framework for new nitrogen-focused narratives based on the widely used Shared Socioeconomic Pathways that include all the major nitrogen-polluting sectors (agriculture, industry, transport and wastewater). These new narratives are the first to integrate the influence of climate and other environmental pollution control policies, while also incorporating explicit nitrogen-control measures. The next step is for them to be used as model inputs to evaluate the impact of different nitrogen production, consumption and loss trajectories, and thus advance understanding of how to address environmental impacts while simultaneously meeting key development goals. This effort is an important step in assessing how humanity can return to the planetary boundary of this essential element over the coming century.

How Hydrologic Connectivity Regulates Water Quality in River Corridors

Downstream flow in rivers is repeatedly delayed by hydrologic exchange with off-channel storage zones where biogeochemical processing occurs. We present a dimensionless metric that quantifies river connectivity as the balance between downstream flow and the exchange of water with the bed, banks, and floodplains. The degree of connectivity directly influences downstream water quality - too little connectivity limits the amount of river water exchanged and leads to biogeochemically inactive water storage, while too much connectivity limits the contact time with sediments for reactions to proceed. Using a metric of reaction significance based on river connectivity, we provide evidence that intermediate levels of connectivity, rather than the highest or lowest levels, are the most efficient in removing nitrogen from Northeastern United States' rivers. Intermediate connectivity balances the frequency, residence time, and contact volume with reactive sediments, which can maximize the reactive processing of dissolved contaminants and the protection of downstream water quality. Our simulations suggest denitrification dominantly occurs in riverbed hyporheic zones of streams and small rivers, whereas vertical turbulent mixing in contact with sediments dominates in mid-size to large rivers. The metrics of connectivity and reaction significance presented here can facilitate scientifically based prioritizations of river management strategies to protect the values and functions of river corridors.

Designing a minimally-invasive, ultrasound-guided, percutaneous flexor tendon sheath lavage technique: a cadaver study

The goal of this study was to develop a minimally-invasive, ultrasound-guided percutaneous flexor tendon sheath lavage technique on cadaver model. Two catheters were inserted using ultrasound guidance at the proximal and distal ends of the tendon sheath in 20 fingers from cadaveric forearms. Percutaneous injection of a saline solution colored with methylene blue resulted in anterograde lavage of the flexor tendon sheath. The technique was successful in 13 out of 20 cases. The proximal catheter was in the correct position in 17 cases and the distal catheter was correctly positioned in 15 cases. The flexor tendons were continuous in all cases and had puncture wounds in 9 cases. Based on our study, this minimally-invasive, ultrasound-guided percutaneous lavage of the flexor tendon sheath was effective in 65% of cases and safe in 100% of cases in the index, middle and ring fingers. If this percutaneous lavage fails, it is always possible to switch to a conventional open technique.

Two-team management of vascular injuries concomitant with osteo-articular injuries in 36 patients over six years

BACKGROUND

Patients with both vascular and osteoarticular injuries require multidisciplinary management. Vascular injuries may be function- and/or life-threatening. The lower limbs are predominantly affected. Traffic, domestic, and work-related accidents contribute most of the cases. The primary objective of this study was to describe the management of patients with concomitant vascular and osteo-articular injuries, with special attention to the rates of amputation and fasciotomy. The secondary objective was to suggest a management sequence to optimise our surgical practice.

HYPOTHESIS

The management sequence is a crucial consideration in patients with both vascular and osteo-articular injuries.

MATERIAL AND METHODS

A 6-year, retrospective, observational study was conducted in patients with concomitant vascular and osteo-articular injuries.

RESULTS

The study included 36 patients with a mean age of 40.6±22.1 years. The main sources of injury were traffic accidents (n=19, 52.8%), crush injury (n=8, 22.2%), and falls (n=5, 13.9%). A compound fracture was present in 20 (55.6%) patients. Evidence of ischaemia in 25 (69.4%) patients, and bleeding in 11 (30.6%) patients. Pre-operative imaging, by ultrasonography or computed tomography, was performed in 27 (75.0%) patients. The lower limb was involved in 30 (83.3%) patients, who had osteoarticular injuries to the femur and leg combined with injury to the popliteal artery. Fasciotomy was performed in 11 (30.6%) patients and secondary amputation in 7 (19.4%) patients. The limb salvage rate was 80.6%. Median patient survival was 9.3 [0-74.8] months.

DISCUSSION

Coordinated work by two surgical teams is crucial to manage concomitant vascular and osteo-articular injuries. The management sequence must be defined clearly. Computed tomography angiography is the investigation of choice and should be performed at the slightest suspicion of vascular injury.

LEVEL OF EVIDENCE

IV, retrospective observational study.

Radiation exposure and the orthopedic surgeon's hand: Measurement of the equivalent dose over 13 months

Exposure to ionizing radiation in the operating room is governed by practical prevention and protection measures on the international, national and local levels. We evaluated the equivalent dose to the hand of an orthopedic surgeon over 13 months. An orthopedic surgeon wore a ring dosimeter on the ring finger of his right hand for all surgical procedures requiring intraoperative fluoroscopy between March 2014 and April 2015. Monthly doses were evaluated by the IRSN over the study period. The number and type of procedures were compiled as well as the type of fluoroscopy unit used. Four hundred procedures were performed during this period, including 182 with fluoroscopy. The equivalent cumulative dose at the hand was 4,75 mSv. No correlation was found with the type of procedure or type of fluoroscopy unit (conventional or mini C-arm). Equivalent doses were below the annual regulatory limit in France of 500 mSv. These results are consistent with those reported in the literature. However, recent studies have noted that both younger surgeons in training and more experienced surgeons must remember to use radiation protection measures.

[Treatment of extra-articular distal radius fractures in active elderly patients]

Extra-articular distal radius fractures in active elderly patients are common and predominantly affect females. The high number of patients lost to follow-up compromises the evaluation of outcomes. Treatment aims to control the comminution and allow fast recovery of pre-injury activity levels. Fixation with volar locking plates is the gold standard. The role of bone substitutes in this type of injury is unclear.

Long-term changes in femoral anteversion and hip rotation following femoral derotational osteotomy in children with cerebral palsy

BACKGROUND

Excessive femoral anteversion is common in cerebral palsy (CP), is often associated with internal hip rotation during gait, and is frequently treated with a femoral derotational osteotomy (FDO). Concerns exist regarding long-term maintenance of surgical outcomes. Past studies report varying rates of recurrence, but none have employed a control group.

METHODS

We conducted a retrospective analysis examining long-term (∼5 years) changes in anteversion and hip rotation following FDO in children with CP. We included a control group that was matched for age and exhibited excessive anteversion (>30°) but did not undergo an FDO. Anteversion, mean stance hip rotation, and rates of problematic remodeling and recurrence were assessed (>15° change and final level outside of normal limits).

RESULTS

The control group was reasonably well matched, but exhibited 9° less anteversion and 3° less internal hip rotation at the pre time point. At a five year follow-up, the FDO group had less anteversion than the control group (20° vs. 35°, p<0.05). The mean stance phase hip rotation did not differ between the groups (4° vs. 5°, p=0.17). Over one third of limbs remained excessively internal in both groups (FDO: 34%, Control: 37%). Rates of problematic recurrence and remodeling were low (0%-11%).

CONCLUSIONS

An FDO is an effective way to correct anteversion in children with CP. Long-term hip rotation is not fully corrected by the procedure, and is not superior to a reasonably well matched control group. Rates of problematic recurrence and remodeling are low, and do not differ between the groups.

Lyme meningoradiculitis: prospective evaluation of biological diagnosis methods

The symptoms of Lyme meningoradiculitis and the value of biological examinations in an endemic area were determined in a prospective study in which data were collected on all patients consecutively hospitalised for Lyme meningoradiculitis at our institution during an 18-month period. Specific antibody titres in the serum and cerebrospinal fluid (CSF) were determined by Vidas enzyme-linked-immunosorbent-assay (IgG + IgM), Dade-Behring enzyme immunoassay (EIA) (IgM; IgG) and Western blot analysis (IgG). We also searched for Borrelia burgdorferi in the CSF by PCR analysis and following culture on a specific medium. A control group was recruited, consisting of 16 consecutive patients who had been referred during the same period with suspected but not confirmed Lyme meningoradiculitis. Eleven patients were included. Borrelia EIA of the serum revealed that 40% of the patients had both elevated specific IgM titres and intrathecal synthesis of specific IgG; 40% of the patients was negative for IgM but had isolated intrathecal synthesis of IgG; 20% of the patients had elevated specific IgM titres without intrathecal synthesis of IgG. PCR analysis and the CSF culture were positive in one case only (B. garinii). The results of this study highlight the importance of systematic serological testing for B. burgdorferi in the CSF in the case of early neuroborreliosis suspicion, even in the absence of IgM serum antibodies, which was the case in 40% of the patients in the present study. Nevertheless, intrathecal anti-B. burgdorferi IgG synthesis, which remains the "gold standard" for the diagnosis of neuroborreliosis, was not detectable in 20% of the patients for whom diagnosis was subsequently confirmed by demonstration of specific serum IgM.

Pneumocystis carinii pneumonia in patients with hematologic malignancies: a descriptive study

Objectives. A retrospective multicentric study was conducted over a five-year period to evaluate the clinical and laboratory characteristics and outcome of patients with proven Pneumocystis carinii pneumonia (PCP) complicating hematologic malignancies.Results. The study included 60 HIV-negative patients with 18 non-Hodgkin's malignant lymphoma (30%), 13 chronic lymphocytic leukaemia (21.7%), 10 acute leukemia (16.6%), 5 multiple myeloma (8.3%), 4 Waldenström's diseases (6.6%), 4 chronic myeloid leukemia (6.6%), 3 myelodysplasia (5%), 2 Hodgkin's diseases (3.3%) and 1 thrombopenia. Bronchoalveolar lavage was diagnostic in all patients. Forty-nine patients received cytotoxic drugs (81.7%), 25 (41.7%) a long-term corticotherapy and 15 (25%) underwent bone marrow transplantation. Twenty-seven patients (45%) required admission in the intensive care unit, 35 (58.3%) received an adjunctive corticotherapy and 18 mechanical ventilation (30%). Twenty patients (33.3%) died of PCP. A previous long-term corticotherapy (p=0.04), high respiratory (p=0.05) and pulse rates (p=0.02), elevated C reactive protein (p=0.01) and mechanical ventilation (OR=13.37; IC: 1.9-50) were associated with a poor prognosis. Adjunctive corticotherapy did not modify the prognosis.Conclusions. These results suggest that PCP can occur during the course of various hematologic malignancies, not only lymphoproliferative disorders. Prognosis remains poor. The diagnosis should be advocated more frequently and earlier to improve the prognosis.

Acquisition of Mn(II) in addition to Fe(II) is required for full virulence of Salmonella enterica serovar Typhimurium

The roles of the genes feoB (ABC ferrous iron transporter), mntH (proton-dependent manganese transporter), and sitABCD (putative ABC iron and/or manganese transporter) in Salmonella pathogenicity were investigated by using mutant strains deficient in one, two, or three transporters. Our results indicated that sitABCD encodes an important transporter of Mn(II) and Fe(II) which is required for full virulence in susceptible animals (Nramp1(-/-)) and for replication inside Nramp1(-/-) macrophages in vitro. The mntH sitABCD double mutant (mutant MS) showed minimal Mn(II) uptake and increased sensitivity to H(2)O(2) and to the divalent metal chelator 2,2'-dipyridyl (DP) and was defective for replication in macrophages. In vivo MS appeared to be as virulent as the sitABCD mutant in Nramp1(-/-) animals. The ferrous iron transporter Feo was required for full virulence in 129/Sv Nramp1(-/-) mice, and infection with multiple mutants lacking FeoB was not fatal. The sitABCD feoB mutant (mutant SF) and the mntH sitABCD feoB mutant (mutant MSF) showed minimal Fe(II) uptake and were slightly impaired for replication in susceptible macrophages. MSF showed reduced growth in minimal medium deficient in divalent cations. The role of the mntH gene, which is homologous to mammalian Nramp genes, was also investigated after overexpression in the double mutant MS. MntH preferred Mn(II) over Fe(II) and could suppress MS sensitivity to H(2)O(2) and to DP, and it also improved the intracellular survival in Nramp1(-/-) macrophages. This study indicates that acquisition of Mn(II), in addition to Fe(II), is required for intracellular survival and replication of Salmonella enterica serovar Typhimurium in macrophages in vitro and for virulence in vivo.

Novel locus required for expression of high-level macrolide-lincosamide-streptogramin B resistance in Staphylococcus aureus

The yycF1(Ts) mutation in Staphylococcus aureus conferred hypersensitivity to macrolide-lincosamide-streptogramin B (MLS(B)) antibiotics on strains either containing or lacking ermB. The overexpression of the S. aureus Ssa protein restored the yycF1 mutant to wild-type levels of susceptibility. Inactivation of ssa in an unmutagenized strain dramatically reduced ermB-based resistance. Conditional loss of function or expression of ssa in the yycF1 mutant is proposed to result in the observed hypersensitivity to MLS(B) antibiotics.

Polyphyletic origins of bacterial Nramp transporters

The redox-active metals iron and manganese are required for energy metabolism, protection against oxidative stress and defense against infections. In eukaryotes, both divalent metals are transported by Nramp transporters. The sequence of these transporters was remarkably conserved during evolution. Several bacterial Nramp homologs (MntH) are also proton-dependent manganese transporters. Here, we present phylogenetic evidence for the polyphyletic origins of three groups of MntH proteins and for possible Nramp horizontal gene transfer with eukaryotes. We propose that the evolution of the MntH/Nramp family is related to adaptation to oxidative environments, including those arising during infection of animals and plants.

Use of a genetic approach to evaluate the consequences of inhibition of efflux pumps in Pseudomonas aeruginosa

Drug efflux pumps in Pseudomonas aeruginosa were evaluated as potential targets for antibacterial therapy. The potential effects of pump inhibition on susceptibility to fluoroquinolone antibiotics were studied with isogenic strains that overexpress or lack individual efflux pumps and that have various combinations of efflux- and target-mediated mutations. Deletions in three efflux pump operons were constructed. As expected, deletion of the MexAB-OprM efflux pump decreased resistance to fluoroquinolones in the wild-type P. aeruginosa (16-fold reduction for levofloxacin [LVX]) or in the strain that overexpressed mexAB-oprM operon (64-fold reduction for LVX). In addition to that, resistance to LVX was significantly reduced even for the strains carrying target mutations (64-fold for strains for which LVX MICs were >4 microg/ml). We also studied the frequencies of emergence of LVX-resistant variants from different deletion mutants and the wild-type strain. Deletion of individual pumps or pairs of the pumps did not significantly affect the frequency of emergence of resistant variants (at 4x the MIC for the wild-type strain) compared to that for the wild type (10(-6) to 10(-7)). In the case of the strain with a triple deletion, the frequency of spontaneous mutants was undetectable (<10(-11)). In summary, inhibition of drug efflux pumps would (i) significantly decrease the level of intrinsic resistance, (ii) reverse acquired resistance, and (iii) result in a decreased frequency of emergence of P. aeruginosa strains highly resistant to fluoroquinolones in clinical settings.

[Cutaneous Scedosporium infection revealed by bullous-necrotic purpura]

BACKGROUND

Non-mycetomatous cutaneous scedosprium is an uncommon mycosis observed in immunodepressed subjects. We report a case with an inaugural presentation of bullous and necrotic purpura.

CASE REPORT

A 79-year-old man on intermittent corticosteroid therapy for bronchospasm was admitted for bullous and necrotic purpura and fever. Subcutaneous nodules with a sporotrichoid aspect developed despite wide-spectrum antibiotics. Microbiology samples cultured on Sabouraud medium evidenced Scedosporium apiospermum. The pathogenic nature of the infection was proven on a skin biopsy showing numerous myceleal filaments with Gomori-Grocott staining despite negative PAS. No pulmonary involvement was evidenced. The patient was treated unsuccessfully with itraconazole. A Pseudomonas lung infection was fatal.

DISCUSSION

Scedosporium apiospermum, an ubiquitous ascomycetes anamorphous to Pseudallescheria boydii, is the cause of a growing number of human infections due to widespread use of immunosuppressors. Skin and lung localizations predominate. The inaugural bullous and necrotic purpural skin manifestations in this case are unusual. In addition, the patient was only minimally immunodepressed and despite demonstrated in vitro sensitivity, itraconazole was ineffective clinically. Treatment is not well defined, but surgery is essential in combination with empirically chosen antifungals.

Genotypic changes in human immunodeficiency virus type 1 associated with loss of suppression of plasma viral RNA levels in subjects treated with ritonavir (Norvir) monotherapy

Ten subjects received 600 to 1,200 mg of the human immunodeficiency virus type 1 (HIV-1) protease inhibitor ritonavir per day. Following 2 weeks of therapy, plasma HIV RNA levels decreased by a mean of 1. 57 (range, 0.89 to 1.96) log units. With continued therapy, HIV RNA levels began to rise in eight subjects. The initial rise in plasma RNA levels was temporally associated with the development and quantitative increase in the V82 resistance mutation. Doubling times of the V82A mutant virus were estimated to be 2.4 to 4.8 days. An L63P/A mutation was commonly present at baseline even in subjects with a durable virologic response. The concomitant acquisition of an L63P/A mutation with the V82A/F mutation at the time when plasma RNA levels rebounded suggests a role for the L63P/A mutation in improving the fitness of the V82A/F mutation. Subsequent additional genotypic changes at codons 54 and 84 were often associated with further increases in plasma RNA levels. Ongoing viral replication in the presence of drugs resulted in the appearance of additional genotypic changes, including the L90M saquinavir resistance mutation, and decreased phenotypic susceptibility. The relative fitness of the protease V82A ritonavir resistance mutation and reverse transcriptase T215Y/F zidovudine resistance mutation following drug withdrawal were estimated to be 96 to 98% that of the wild type. Durability of the virologic response was associated with plasma RNA levels at the nadir. A virologic response beyond 60 days was not observed unless plasma HIV RNA levels were suppressed below 2,000 copies/ml, consistent with estimates from V82A doubling times for selection of a single resistance mutation to dominate the replicating population.

Nonisotopic hybridization assay for determination of relative amounts of genotypic human immunodeficiency virus type 1 zidovudine resistance

A nonisotopic hybridization assay for human immunodeficiency virus genotypic zidovudine resistance determination is described. Biotinylated PCR product was hybridized with enzyme-labeled probes for wild-type or resistant mutant sequences and detected colorimetrically or chemiluminescently in a microplate format. Changes in mutant-to-wild-type ratios allow for the monitoring of longitudinal patient samples.

Determination of human immunodeficiency virus RNA in plasma and cellular viral DNA genotypic zidovudine resistance and viral load during zidovudine-didanosine combination therapy

Eleven human immunodeficiency virus (HIV)-infected subjects on long-term zidovudine (ZDV) therapy had didanosine (ddI) added to their antiretroviral regimen. HIV RNA in plasma was quantitated by branched-DNA signal amplification assay. Peripheral blood mononuclear cell (PBMC) HIV viral DNA was quantitated by PCR. The relative amounts of wild-type (WT) sequence, ddI resistance-associated codon changes (reverse transcriptase [RT] gene codon 65 K-->R [RT K65R], RT 174V, RT I135K/T/V, and RT M184I/V), and ZDV resistance-associated codon change (RT T215Y/F) from HIV RNA in plasma and RT T215Y/F from PBMC viral DNA were determined by differential hybridization of PCR products from 10 of 11 subjects. All subjects had evidence of RT T215Y/F mutation in both RNA in plasma and PBMC DNA at baseline. Subjects with a mixture of WT and RT T215Y/F HIV RNA in plasma at baseline demonstrated a decline in RNA levels in plasma after the addition of ddI. However, after 6 months of ZDV-ddI therapy, WT HIV RNA in plasma was undetectable in all subjects who had demonstrated a mixture at baseline. Subjects with only RT T215Y/F RNA present in plasma at baseline remained so and demonstrated no decline in RNA levels in plasma. In all subjects, no significant changes in PBMC DNA viral load and RT T215Y/F or WT levels were seen. HIV RNA in plasma demonstrated a significantly higher RT T215Y/F mutant/WT ratio than that of PBMC viral DNA, both at baseline and after ZDV-ddI combination therapy in all subjects. No subjects developed mutations associated with ddI resistance at codons 65, 74, 135, and 184 during this study. This study suggests that determination of relative amounts of RT T215Y/F and WT species from HIV RNA in plasma at baseline may be predictive of virologic response during ZDV-ddI combination therapy.

[Invasive cysticercosis due to Taenia crassiceps in an AIDS patient]

A first case is reported from France of a subcutaneous and muscular tissues invasion by proliferative larval forms of Taenia crassiceps in an AIDS-patient with severe immunodeficiency. These larvae usually develop in rodents whereas the adult form of the cestode is commonly found in foxes. Authors emphasize the differential diagnosis from other human subcutaneous metacestodoses such as T. solium cysticercosis, cenurosis and hydatidosis. The proliferative aspect of the larvae, the recurrence of lesions after surgical removal and the possible invasion of other tissues are elements of a poor prognosis.

[Anatomical sections at low temperature]

The authors present anatomical sections realized with a "scanigraph": an unedited self acting apparatus specially conceived for the exploration of anatomical specimens. It is possible to take photographs of successive parallel plans, scanned at 18, 9 or 6 pictures by millimeter. With the help of a computer, anatomical sections could be reconstituted in orthogonal projection and axial incidence. The results obtained reveal a new process in anatomical investigation.