[Clinical characteristics and prognostic factors of breast cancer patients with tumor deposits in the ipsilateral axillary region]

Objective: To investigate the clinicopathologic features and prognostic factors of breast cancer patients with tumor deposits in the ipsilateral axillary region. Methods: We retrospectively analyzed the clinicopathologic data and follow-up results of 155 patients with breast cancer diagnosed for the first time and complicated with tumor deposits in the ipsilateral axillary region in the Department of Thyroid-Breast-Vascular Surgery of Xijing Hospital from January 2008 to September 2018. Kaplan-Meier method was used for survival analysis. Log rank test was used for the univariate analysis of prognostic factors, and Cox regression was used for multivariate analysis. Results: The median disease free survival (DFS), median distant metastasis free survival (DMFS), and median overall survival (OS) of the 155 patients were 52.0 months, 66.6 months, and 102.2 months, respectively. The 5-year and 10-year DFS rates were 45.7% and 23.1%, the 5-year and 10-year DMFS rates were 56.9% and 28.9%, and the 5-year and 10-year OS rates were 79.3% and 46.0%, respectively. Multivariate Cox regression analysis showed that family tumor history (HR=0.362, 95% CI: 0.140-0.937), clinical T stage (T3: HR=3.508, 95% CI: 1.380-8.918; T4: HR=2.220, 95% CI: 1.076-4.580), estrogen/progesterone receptor status (HR=0.476, 95% CI: 0.261-0.866), number of tumor deposits (HR=1.965, 95% CI:1.104-3.500) and neoadjuvant chemotherapy (HR=1.961, 95% CI: 1.032-3.725) were independent influencing factors for DFS. Molecular subtype [human epidermal growth factor receptor-2(HER-2) positive and hormone receptor negative: HR=7.862, 95% CI: 3.189-19.379], number of tumor deposits (HR=2.155, 95% CI: 1.103-4.212), neoadjuvant chemotherapy (HR=5.002, 95% CI: 2.300-10.880) and radiotherapy (HR=2.316, 95% CI: 1.005-5.341) were independent influencing factors of DMFS. Histological grade (HR=4.362, 95% CI: 1.932-9.849), estrogen/progesterone receptor expression (HR=0.399, 95% CI: 0.168-0.945), HER-2 expression (HR=2.535, 95% CI: 1.114-5.768) and neoadjuvant chemotherapy (HR=4.080, 95% CI: 1.679-9.913) were independent influencing factors of OS. Conclusions: The presence of tumor deposits weakens the influence of axillary lymph node status and distant metastases on the prognosis of breast cancer patients. Therefore, a clinicopathological staging system taking into account tumor deposits should be developed. Since the number of tumor deposits affects the risk of recurrence and metastasis of breast cancer patients, we recommend that the number of tumor deposits should be reported in detail in the pathological report after breast cancer surgery.

Variant spectrum of F8 and F9 in hemophilia patients from southern China and 26 novel variants

Hemophilia, an X-linked recessive disorder, is characterized by spontaneous or trauma-induced prolonged bleeding. It is classified as hemophilia A when caused by variants in the F8 gene, and hemophilia B when caused by F9 variants. Few studies have described hemophilia variants in the Chinese population. This study aimed to investigate the clinical and genetic profiles of 193 hemophilia patients from southern China. Utilizing Sanger sequencing, multiplex ligation-dependent probe amplification, gap detection, long-range PCR, and multiplex PCR, we identified both F8 and F9 gene variants. Pregnant women with a history of hemophilia A offspring underwent amniocentesis or villus sampling for the variant detection. Variants in F8 and F9 were pinpointed in 183 patients, with 26 being novel discoveries. Notably, genetic testing was absent in the initial evaluation of 133 out of 161 patients, leading to a protracted average definitive diagnosis timeline of 2 years. Remarkably, two hemophilia A cases with anticipated severe phenotypes due to protein-truncating variants presented with only moderate or mild clinical manifestations. Among the 40 fetuses tested, 34 were males, with 17 exhibiting hemizygous variants in the F8 gene. Our results contribute to the broader understanding of F8 and F9 variant spectrum and highlight the underuse of genetic analyses in southern China.

Depot buprenorphine as an opioid agonist therapy in New South Wales correctional centres: a costing model

Background

In 2019 daily liquid methadone and sublingual buprenorphine-naloxone were primary opioid agonist treatments for correctional centres in New South Wales, Australia. However, both had significant potential for diversion to other patients, and their daily administration was resource intensive. An alternative treatment in the form of subcutaneous depot buprenorphine became a viable option following a safety trial in 2020 – the UNLOC-T study. Depot preparation demonstrated advantages over current treatments as more difficult to divert and requiring fewer administrations. This paper reports the results of economic modelling of staffing costs in medication administration comparing depot buprenorphine, methadone, and sublingual buprenorphine provision in UNLOC-T trial facilities.

Methods

The costing study adopted a micro-costing approach involving the synthesis of cost data from the UNLOC-T clinical trial as well as data collected from Justice Health and Forensic Mental Health Network records. Labour and materials data were collected during site observations and interviews. Costs were calculated from two payer perspectives: a) the New South Wales (state) government which funds custodial and health services; and b) the Australian Commonwealth government, which pays for medications. The analysis compared the monthly-per-patient cost for each of the three medications in trial-site facilities during July 2019. This was followed by simulation of depot buprenorphine implementation across the study population. Costs associated with medical assessment and reviews were excluded.

Results

The monthly-per-patient New South Wales government service costs of depot buprenorphine, methadone and sublingual buprenorphine were: $151, $379 and $1,529 respectively while Commonwealth government medication costs were $434, $80 and $525. The implementation simulation found that service costs of depot buprenorphine declined as patients transitioned from weekly to monthly administration. Costs of treatment using the other medications increased as patient numbers decreased alongside fixed costs. At 12 months, monthly-per-patient service costs for depot buprenorphine, methadone and sublingual buprenorphine—which would be completely phased out by month 13—were $92, $530 and $2,162 respectively.

Conclusions

Depot buprenorphine was consistently the least costly of the treatment options. Future modelling could allow for dynamic patient populations and downstream impacts for participants and the state health system.

Trial registration

ACTRN12618000942257. Registered 4 June 2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-08687-8.

Preoperative MRI of breast squamous cell carcinoma: diagnostic value of distinguishing between two subtypes

AIM

To retrospectively analyse the clinical and MRI data of primary squamous cell carcinoma (SCC), particularly pure squamous cell carcinoma (PSCC) and mixed squamous cell carcinoma (MSCC).

MATERIALS AND METHODS

The MRI data and clinicopathological characteristics of 20 patients with histopathologically confirmed SCC of the breast, including eight PSCC patients and 12 MSCC patients, from multiple centres between January 2013 and December 2020 were analysed retrospectively.

RESULTS

Nine of 12 patients in the MSCC group showed hyperintensity on T1-weighted imaging (WI), while this feature was not observed in the PSCC group (p=0.001). Most of the PSCC group showed rim enhancement, whereas most of the MSCC group showed heterogeneous enhancement (p=0.007). In addition, there was no significant difference in the thickness of the rim enhancement and the percentage of necrotic components in the tumours between the two types of SCCs of the breast (p=0.545 and p=0.662, respectively). Four patients (4/12) in the MSCC group had sentinel lymph node metastasis, while only one patient (1/8) in the PSCC group showed lymph node metastasis (p=0.603). Metastatic disease occurred in 25% of patients with PSCC and in approximately 41.7% of patients with MSCC.

CONCLUSION

The signal on T1WI and internal enhancement characteristics were the key features for differentiating PSCC and MSCC. Therefore, MRI phenotypes may provide additional information for the pathological classification of breast SCC.

Efficacy and safety of delafloxacin compared with vancomycin plus aztreonam for acute bacterial skin and skin structure infections: a Phase 3, double-blind, randomized study

Background

Delafloxacin is an investigational anionic fluoroquinolone in development for oral or intravenous administration for the treatment of infections caused by Gram-positive (including MRSA), Gram-negative, atypical and anaerobic organisms.

Objectives

To establish the non-inferiority of delafloxacin compared with vancomycin plus aztreonam for the treatment of acute bacterial skin and skin structure infections and to compare the safety of the two antimicrobials.

Patients and methods

A Phase 3, multicentre, randomized, double-blind, active-controlled study with 660 patients compared delafloxacin 300 mg or vancomycin 15 mg/kg plus aztreonam 2 g each administered twice daily intravenously for 5–14 days. Non-inferiority was evaluated by objective response (≥20% erythema reduction) at 48–72 h after initiation of study drug, investigator subjective assessment of outcome and microbiological responses. Clinical Trials Registration: NCT01811732. EudraCT number: 2012-001767-71.

Results

In the ITT analysis set, the objective response was 78.2% in the delafloxacin arm and 80.9% in the vancomycin/aztreonam arm (mean treatment difference, −2.6%; 95% CI, −8.78% to 3.57%). Investigator-assessed cure was similar between the two groups at follow-up (52.0% versus 50.5%) and late follow-up (70.4% versus 66.6%). Bacterial eradication of MRSA was 100% and 98.5% in the delafloxacin group and the vancomycin/aztreonam group, respectively. Frequency of treatment-emergent adverse events in the delafloxacin and vancomycin/aztreonam groups was similar. Treatment-emergent adverse events leading to study drug discontinuation were higher in the vancomycin/aztreonam group compared with the delafloxacin group (4.3% versus 0.9%).

Conclusions

Delafloxacin, an anionic fluoroquinolone, was statistically non-inferior to vancomycin/aztreonam at 48–72 h following the start of therapy and was well tolerated as monotherapy in the treatment of acute bacterial skin and skin structure infections.

Effects of Herceptin on circulating tumor cells in HER2 positive early breast cancer

The objective of this study was to determine the changes in peripheral blood circulating tumor cells in HER2-positive early breast cancer before and after Herceptin therapy, and to explore the effects of the HER2 gene and Herceptin on circulating tumor cells. CK19 mRNA expression in peripheral blood was evaluated by qRT-PCR as an index of circulating tumor cells in 15 cases of HER-2-positive breast cancer and 18 cases of HER2-negative breast cancer before, and after chemotherapy as well. Ten cases of HER2-positive breast cancer continued on Herceptin therapy for 3 months after chemotherapy, and their peripheral blood was again drawn and assayed for CK-19 mRNA expression. Preoperatively, all cases of HER2-positive cancer were positive for CK19 mRNA in peripheral blood, but 6 cases of HER2-negative breast cancer were positive (33.3%), where there was a substantial difference between the two groups. After 6 cycles of adjuvant chemotherapy, CK19 positive rates in cases of HER2-positive and -negative breast cancer reduced by 93.3 and 11.1%, respectively, with a significant difference still existing. After 3 months of Herceptin therapy, expression of CK19 mRNA declined considerably in 10 cases of HER2 positive breast cancer (113.66 ± 88.65 vs 63.35 ± 49.27, P = 0.025). HER-2 gene expression closely correlated with circulating tumor cells in peripheral blood of early breast cancer patients. Moreover, Herceptin, a monoclonal antibody for HER2, can reduce the number of circulating tumor cells, which can be an early predictive factor for Herceptin therapy effectiveness against breast cancer.

Capillary pressure may predict preclinical changes in the eye

AIMS/HYPOTHESIS

Microvascular dysfunction is associated with end-organ damage. Macular oedema is an important component of diabetic retinopathy. Macular thickness can be accurately quantified by optical coherence tomography (OCT), enabling accurate assessment of the macular prior to clinically apparent abnormalities. We investigated whether macular (fovea) thickness in non-diabetic individuals is related to the microvascular variables controlling fluid filtration across a blood vessel wall, in particular capillary pressure and the microvascular filtration capacity (Kf).

METHODS

We recruited 50 non-diabetic individuals (25 men, 25 women; age range: 26-78 years; BMI range: 20-46 kg/m(2)). Fovea thickness was assessed by OCT. Microvascular assessments included: finger nailfold capillary pressure; Kf; microvascular structural assessments, i.e. skin vasodilatory capacity, minimum vascular resistance (MVR) and microvascular distensibility; and endothelial function.

RESULTS

At 214.6 (19.9) microm (mean [SD]), fovea thickness was within normal range. Capillary pressure, adjusted for BMI, was associated with fovea thickness (standardised beta 0.573, p = 0.006, linear regression). Fovea thickness was not associated with Kf, microvascular structural assessments or endothelial function. Capillary pressure was still associated with fovea thickness when adjusted for microvascular variables (Kf, vasodilatory capacity, MVR, microvascular distensibility or endothelial function), or for risk factors for diabetes (systemic blood pressure, insulin sensitivity, inflammation, glycaemic status and lipids) and age.

CONCLUSIONS/INTERPRETATION

Capillary pressure, a key determinant of movement of fluid across a blood vessel wall, is associated with fovea thickness in non-diabetic individuals. This suggests that with regard to potential preventative or therapeutic targets, attention should be directed at the mechanisms determining retinal microvascular pressure.

Living-related small bowel transplantation for three patients with short gut syndrome

OBJECTIVE

We summarized our experience of living-related small bowel transplantation and postoperative management of 3 patients with short gut syndrome.

METHODS

Patient #1, an 18-year-old boy, received a 150-cm segment of distal ileum with a vascular pedicle of distal superior mesenteric artery and vein, which was donated by his father. Patient #2, a 15-year-old boy, received a 160-cm graft of distal ileum from his mother. Patient #3, a 17-year-old boy, received a 170-cm graft of distal ileum from his father. The graft artery and vein were anastomosed to the recipient infrarenal aorta and vena cava, respectively, in end-to-side fashion using 7/0 Prolene suture. Intestinal continuity was restored by anastomosis of proximal end of the graft to the recipients' own proximal jejunum, the distal end was left open as a stoma. The recipient distal gut was anastomosed to the distal end of the graft. All 3 recipients were given FK506 (tacrolimus) regularly combined with periodic mycophenolate mofetil. In cases of acute rejection, large doses of steroids were administered to the recipients.

RESULTS

The recipients and donors had fairly unremarkable postoperative courses. So far, patient #1 has survived for 7 years and 6 months with a well-functioning graft and without requirement for total parenteral nutrition (TPN) support. His body weight increased 20 kg and of his life quality has dramatically improved. Patient #2, however, died of acute rejection with fatal sepsis at 5 months after transplantation. Patient #3 has survived for 3 years and 8 months enjoying a normal life. Postoperative recovery of all 3 donors was unremarkable. They were discharged 12 days after surgery without complications.

CONCLUSION

Outcomes of the implantation using the distal ileum as a graft in living-related small bowel transplantation have been satisfactory for both recipients and donors. It is feasible to anastomose the graft artery and vein to the recipient infrarenal aorta and vena cava. The intestinal continuity can be restored by a 1-stage strategy with minimal risk to the recipient. Appropriate application and adjustment of immune suppressors are crucial for the recipients to experience high-quality lives.

Presumed infectious endophthalmitis following cataract surgery in the UK: a case–control study of risk factors

AIMS

To study risk factors for presumed infectious endophthalmitis complicating cataract surgery in the United Kingdom.

METHODS

Two hundred and fourteen clinically diagnosed patients with presumed infectious endophthalmitis were compared with 445 control patients throughout the United Kingdom in a prospective case-control study. The cases were identified through the British Ophthalmological Surveillance Unit reporting card system. Control patients undergoing cataract surgery from 13 'control centres' throughout the United Kingdom were selected randomly. Risk factors were identified by univariate and multivariate logistic regression analyses. Pertinent variables relating to the cataract extraction procedure, antimicrobial prophylaxis, ophthalmic and medical history were analysed with regard to postoperative infection.

RESULTS

Statistically significant risk factors in the multivariate model included inpatient cataract surgery (P=0.001), surgery in dedicated eye theatres (P<0.001), consultant grade surgeon (compared to registrar) (P=0.001), posterior capsule tear during cataract surgery (P=0.001). The use of face masks by the scrub nurse and surgeon during cataract surgery (P<0.001) and the administration of subconjunctival antibiotics at the end of surgery (P<0.001) were protective against postoperative infection.

CONCLUSIONS

In order to minimise the risk of postoperative endophthalmitis we would recommend the wearing of face masks by the surgeon and scrub nurse during cataract surgery and subconjunctival antibiotics at the end of surgery.

Effect of small-sized liposomal Adriamycin administered by various routes on a metastatic breast cancer model

The antitumor effects of small-sized liposomal Adriamycin (LADR) administered by various routes were investigated in rabbits bearing well-developed VX2 tumors in the mammary gland. Rabbits received s.c. or i.v., or s.c. combined with i.v., injections of LADR 6 weeks after tumor implantation. The i.v. route showed a significant inhibitory effect on breast tumors and distant metastases. In comparison, metastases in axillary and mediastinal lymph nodes were more efficiently inhibited after s.c. injection. LADR administered concurrently by both the i.v. and s.c. routes produced satisfactory therapeutic activities on both primary breast tumors and metastases in local-regional lymph nodes, lungs and liver, as shown by slowed growth rates, decreased mRNA expression of proliferating cell nuclear antigen, and extensive necrosis and apoptosis of tumor cells. It is concluded that small-sized LADR administered s.c. provides reliable efficacy on lymphatic metastases of breast cancer and that the addition of treatment by the s.c. route to that by the conventional i.v. route can be recommended as a promising procedure to enhance chemotherapeutic effects in patients with metastatic breast cancer.

Surveillance of endophthalmitis following cataract surgery in the UK

AIMS

To estimate the incidence of acute-onset presumed infectious endophthalmitis (PIE) following cataract surgery in the UK and provide epidemiological data on the presentation, management, microbiology, and outcome of cases of endophthalmitis.

METHODS

Cases were identified prospectively by active surveillance through the British Ophthalmological Surveillance Unit reporting card system, for the 12-month period October 1999 to September 2000 inclusive. Questionnaire data were obtained from ophthalmologists throughout the UK at baseline and 6 months after diagnosis. Under-reporting was estimated by independently contacting units with infection databases.

RESULTS

Data were available on 213 patients at baseline and 201 patients at follow-up. The minimum estimated incidence of PIE was 0.086 per 100 cataract extractions and the corrected incidence was 0.14 per 100 cataract extractions. For the management of PIE, 96% of patients received intravitreal, 30% subconjunctival, 65% oral, and 17% intravenous antibiotics. In all, 17% of patients received intravitreal steroid. From the intraocular samples taken for microbiological analysis, 56% were culture positive. At follow-up, 48% of patients achieved visual acuity of 6/12 or better and 66% achieved better than 6/60. 13% of patients were unable to perceive light or had evisceration of the globe.

CONCLUSIONS

The incidence of PIE after cataract surgery in the UK is comparable to that of other studies. Approximately 50% of patients achieved a visual acuity close to the driving standard.

Suprachoroidal haemorrhage complicating cataract surgery in the UK: a case control study of risk factors

AIMS

To study the risk factors for suprachoroidal haemorrhage (SCH) complicating cataract surgery in the United Kingdom.

METHODS

109 cases of SCH complicating cataract surgery prospectively collected through the British Ophthalmological Surveillance Unit were compared with 449 controls that underwent cataract extraction from 13 "control centres" throughout UK in a case control study. 40 systemic, ophthalmic, and operative variables were examined.

RESULTS

Statistically significant risk factors for SCH in univariate analysis included: older age (p<0.001), taking at least one cardiovascular medication (p<0.001), peripheral vascular disease (p = 0.014), hyperlipidaemia (p = 0.005), glaucoma (p<0.001), elevated preoperative intraocular pressure (p<0.001), sub-Tenon's local anaesthesia (LA) (p<0.001), topical LA (p<0.001), the lack of orbital compression following LA (p<0.001), posterior capsule (PC) rupture before SCH (p<0.001), elective extracapsular cataract extraction (ECCE) (p = 0.038), and phacoemulsification conversion (p<0.001). Logistic regression analysis identified the following significant independent risk factors: older age, taking at least one cardiovascular medication, glaucoma, elevated preoperative intraocular pressure, the lack of orbital compression, PC rupture before SCH, elective ECCE, and phacoemulsification conversion.

CONCLUSION

The results allow identification of patients at risk of SCH. Attention to the various modifiable preoperative and intraoperative risk factors is recommended in order to minimise the risk of SCH.

Suprachoroidal haemorrhage complicating cataract surgery in the UK: epidemiology, clinical features, management, and outcomes

AIMS

To study the incidence, management, and outcomes of suprachoroidal haemorrhage (SCH) complicating cataract surgery in the United Kingdom.

METHODS

Cases were prospectively collected by active surveillance through the British Ophthalmological Surveillance Unit. Details were obtained using an incident questionnaire with follow up at 6 months.

RESULTS

118 cases were reported in 1 year. The estimated incidence of SCH was 0.04% (95% confidence interval 0.034% to 0.050%). Cataract extractions were by phacoemulsification in 76.2%, extracapsular cataract extraction (ECCE) in 11.0%, and phacoemulsification conversion in 12.8%. SCH was "limited" (1 to 2 quadrants) in 48.7%, "full blown" (3 to 4 quadrants) in 43.1%. SCH in phacoemulsification was more likely to be limited (63.2%), compared with ECCE (11.1%) and phacoemulsification conversion (23.1%) (p<0.001, chi(2) test). Visual acuity (VA) was better than 6/60 in 57 of 95 (60%) cases after a median follow up interval of 185 days. 33 of 34 cases (97.1%) with secondary anterior segment revision had VA better than 6/60. VA was worse than 6/60 in 7 of 8 (87.5%) cases that had intraoperative sclerostomy, and in all 6 (100%) cases that had secondary posterior segment intervention.

CONCLUSION

SCH is a rare but serious complication of cataract surgery. Poor prognostic factors included full blown SCH, ECCE, phacoemulsification conversion, retinal apposition, and retinal detachment.

Presbyopic phacovitrectomy

AIM

To review the results and complications of combined phacoemulsification and vitrectomy in presbyopic patients.

METHODS

Retrospective review of 90 consecutive presbyopic patients who underwent phacoemulsification and vitrectomy for primary rhegmatogenous retinal detachment (RRD) (21), redo-RRD (seven), stages 2 and 3 full thickness macular holes (FTMH) (38), stage 4 FTMH (six), idiopathic epiretinal membrane (ERM) (11), proliferative diabetic retinopathy (PDR) (three) and vitreous haemorrhage secondary to branch retinal vein occlusion (BVO) (four).

RESULTS

Lens opacity was absent or mild in 84.5% of patients. Reattachment rates for primary RRD and redo-RRD after one procedure were 90.5% and 71.4% and final reattachment rates were 95.2% and 100%, respectively. Macular hole closure rate was 89.5% for stage 2 and 3 FTMH and 83.3% for stage 4 FTMH. There was significant improvement in the median logMAR visual acuity from 1.00 preoperatively to 0.48 postoperatively for the whole cohort (p<0.001, Wilcoxon test). Postoperative complications included fibrinous uveitis (13.3%), iris bombe (2.2%), IOL/iris capture secondary to gas overfill (1.1%), and posterior capsule opacification (51.1%).

CONCLUSION

Combined phacoemulsification and vitrectomy is a safe and desirable option in the management of phakic, presbyopic patients with vitreoretinal pathologies that warrant vitreous surgery, even in the absence of significant lens opacity.

Longitudinal study of a cohort of people with diabetes screened by the Exeter Diabetic Retinopathy Screening Programme

PURPOSE

To evaluate the long-term outcome of a cohort of people with diabetes screened by the Exeter Diabetic Retinopathy Screening Programme.

METHOD

The cohort comprised of diabetic patients from nine market town General Practices around Exeter who first attended the diabetic retinopathy screening programme in 1992. Screening was carried out by a combination of dilated fundoscopy by a screening technician and a single 45 degrees Polaroid photograph of each eye. The prevalence of diabetic retinopathy at the baseline, the incidence of sight threatening diabetic retinopathy (STDR) in the next two rounds of screenings, and the long-term visual outcome are described.

RESULTS

The cohort consisted of 775 patients (104 Type I, 517 Type II non-insulin-requiring and 154 Type II insulin-requiring). The mean age was 72.1 years (15-100), with mean disease duration of 13.0 years (1-79). Baseline prevalence was as follows: background retinopathy: 21.4%, proliferative: 2.8%, clinically significant macular oedema: 6.1%. The incidence of proliferative disease was 2.20% and 2.25% respectively in the next two rounds of screening (P > 0.05, chi2 test). The incidence of clinically significant macular oedema was also constant over next two rounds of screening, at 4.79% and 5.18% respectively (P > 0.05, chi2 test). Ninety-five (12.3%) patients were deceased and a further 179 (23%) patients were lost to follow-up by the third round. Only two patients with newly diagnosed STDR suffered deterioration of visual acuity to 6/60 or worse as a result of diabetic retinopathy.

CONCLUSION

The incidence of STDR remained constant throughout the period of screening, reflecting the chronic progressive nature of the disease. Significant numbers of patients were lost to follow-up. Screening seemed effective in preserving vision in those patients with newly diagnosed STDR.

Detection of sporadic cases of hepatitis E virus (HEV) infection in China using immunoassays based on recombinant open reading frame 2 and 3 polypeptides from HEV genotype 4

We reported previously on the complete sequence of hepatitis E virus (HEV) genotype 4, isolated from patients with sporadic cases of acute HEV infection in China. At least eight HEV genotypes have now been described worldwide, and further isolates await classification. Current immunoassays for the detection of anti-HEV antibodies are based on polypeptides from genotypes 1 and 2 only and may be inadequate for the reliable detection of other genotypes. Because genotypes 1 and 4 predominate in China, we wished to investigate the antigenic reactivities of HEV genotype 4 proteins. Four overlapping regions of open reading frame 2 (ORF2) (FB5, amino acids [aa] 1 to 130; E4, aa 67 to 308; F2-2, aa 288 to 461; E5, aa 414 to 672) and the entire ORF3 product were expressed in Escherichia coli as fusion proteins. Enzyme immunoassays based on each of the five purified polypeptides were evaluated with sera from patients with sporadic cases of acute HEV infection. Individual immunoassays derived from HEV genotype 4 detected more cases of acute hepatitis E than a commercial assay. Some serum samples, which were positive for anti-HEV immunoglobulin G only by assays based on HEV genotype 4, were positive for HEV RNA by reverse transcription-PCR. Polypeptide FB5, from the N terminus of ORF2, had the greatest immunoreactivity with sera from patients with acute hepatitis E. These data indicate that the N terminus of ORF2 may provide epitopes which are highly reactive with acute-phase sera and that assays based on genotypes 1 and 2 alone may be inadequate for the detection of HEV infection in China, where sporadic cases of HEV infection are caused predominantly by HEV genotypes 4 and 1.

Traumatic rupture of the medial rectus muscle

Traumatic rupture of an extraocular muscle, in the absence of significant injury to the globe and adnexa, is uncommon. We report the case of a patient with an isolated mid-belly rupture of the medial rectus muscle following ocular trauma and describe the technique of repairing the ruptured muscle by suturing the distal segment to the Tenon sleeve of the proximal segment. This was combined with postoperative botulinum toxin injection to the ipsilateral lateral rectus muscle. Good primary position alignment was achieved 7 months after surgery. The patient regained a useful horizontal field of binocular single vision totaling 27 degrees.

Involvement of transporter recruitment as well as gene expression in the substrate-induced adaptive regulation of amino acid transport system A

We investigated the molecular mechanism involved in the adaptive regulation of the amino acid transport system A, a process in which amino acid starvation induces the transport activity. These studies were done with rat C6 glioma cells. System A activity in these cells is mediated exclusively by the system A subtype, amino acid transporter A2 (ATA2). The other two known system A subtypes, ATA1 and ATA3, are not expressed in these cells. Exposure of these cells to an amino acid-free medium induces system A activity. This process consists of an acute phase and a chronic phase. Laser-scanning confocal microscopic immunolocalization of ATA2 reveals that the acute phase is associated with recruitment of preformed ATA2 from an intracellular pool to the plasma membrane. In contrast, the chronic phase is associated with an induction of ata2 gene expression as evidenced from the increase in the steady-state levels of ATA2 mRNA, restoration of the intracellular pool of ATA2 protein, and blockade of the induction by cycloheximide and actinomycin D. The increase in system A activity induced by amino acid starvation is blocked specifically by system A substrates, including the non-metabolizable alpha-(methylamino)isobutyric acid.

Evidence for the transport of neutral as well as cationic amino acids by ATA3, a novel and liver-specific subtype of amino acid transport system A

We report here on the cloning and functional characterization of the third subtype of amino acid transport system A, designated ATA3 (amino acid transporter A3), from a human liver cell line. This transporter consists of 547 amino acids and is structurally related to the members of the glutamine transporter family. The human ATA3 (hATA3) exhibits 88% identity in amino acid sequence with rat ATA3. The gene coding for hATA3 contains 16 exons and is located on human chromosome 12q13. It is expressed almost exclusively in the liver. hATA3 mediates the transport of neutral amino acids including alpha-(methylamino)isobutyric acid (MeAIB), the model substrate for system A, in a Na(+)-coupled manner and the transport of cationic amino acids in a Na(+)-independent manner. The affinity of hATA3 for cationic amino acids is higher than for neutral amino acids. The transport function of hATA3 is thus similar to that of system y(+)L. The ability of hATA3 to transport cationic amino acids with high affinity is unique among the members of the glutamine transporter family. hATA1 and hATA2, the other two known members of the system A subfamily, show little affinity toward cationic amino acids. hATA3 also differs from hATA1 and hATA2 in exhibiting low affinity for MeAIB. Since liver does not express any of the previously known high-affinity cationic amino acid transporters, ATA3 is likely to provide the major route for the uptake of arginine in this tissue.

Local anaesthetic techniques and pulsatile ocular blood flow

AIM

To compare pulsatile ocular blood flow (POBF) and intraocular pressure (IOP) between eyes of patients receiving either peribulbar (with and without balloon compression) or subconjunctival local anaesthesia (LA).

METHODS

30 eyes of 30 patients undergoing cataract surgery by phacoemulsification were investigated in a study of parallel group design. Ten patients had peribulbar LA and 10 minutes compression with a Honan's balloon (group A). A further 10 patients who received peribulbar LA alone (group B) acted as controls for the effects of balloon compression. Ten other patients were given subconjunctival LA (group C). POBF and IOP were measured using a modified Langham pneumatonometer. Three measurements were made in each eye, the first recording immediately before LA, the second 1 minute after, and the third 10 minutes after LA.

RESULTS

No significant change in POBF or IOP was recorded in eyes receiving subconjunctival LA. In the peribulbar groups (A and B), there was a drop in median POBF of 252 and 138 microl/min respectively 1 minute after LA, which was statistically significant in both groups (p<0. 01). By 10 minutes, POBF tended to return to baseline levels, but remained significantly reduced in group B (p<0.05). In addition, there was a significant (p<0.05) reduction in IOP (mean drop of 4.82 mm Hg) in group A following peribulbar LA with balloon compression.

CONCLUSIONS

POBF was significantly reduced after peribulbar LA but was unchanged after subconjunctival LA. Balloon compression reduced IOP and improved POBF following peribulbar LA. The findings may have clinical implications in patients with compromised ocular circulation or significant glaucomatous optic neuropathy.

A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization

Changes in iron supply to oceanic plankton are thought to have a significant effect on concentrations of atmospheric carbon dioxide by altering rates of carbon sequestration, a theory known as the 'iron hypothesis'. For this reason, it is important to understand the response of pelagic biota to increased iron supply. Here we report the results of a mesoscale iron fertilization experiment in the polar Southern Ocean, where the potential to sequester iron-elevated algal carbon is probably greatest. Increased iron supply led to elevated phytoplankton biomass and rates of photosynthesis in surface waters, causing a large drawdown of carbon dioxide and macronutrients, and elevated dimethyl sulphide levels after 13 days. This drawdown was mostly due to the proliferation of diatom stocks. But downward export of biogenic carbon was not increased. Moreover, satellite observations of this massive bloom 30 days later, suggest that a sufficient proportion of the added iron was retained in surface waters. Our findings demonstrate that iron supply controls phytoplankton growth and community composition during summer in these polar Southern Ocean waters, but the fate of algal carbon remains unknown and depends on the interplay between the processes controlling export, remineralisation and timescales of water mass subduction.

Unusual hepatitis B surface antigen variation in a child immunised against hepatitis B

Perinatal transmission of and infection with hepatitis B (HBV) in early childhood are observed in a small proportion of the offspring of hepatitis B surface antigen (HBsAg)-positive mothers who are vaccinated against HBV immediately after giving birth. The children may be infected by wild-type HBV or by variants with amino acid substitutions in the "a" determinant of HBsAg, particularly at position 145 and, rarely, at positions 120, 126, 129, 131, 141, and 144. Four hundred and forty-six newborn infants of HBsAg-positive mothers in the northeastern part of the Czech Republic received combined active and passive immunisation against HBV. Only one child became an HBsAg carrier. This followed a mild, acute HBV illness in the beginning of the second year of his life. HBV DNA encoding the "a" determinant and surrounding region of HBsAg was sequenced after amplification from the plasma of the child and his mother. The child was infected with variants of HBsAg with substitutions at residues 137 and 139. The virus of the mother had changes at residues 120 and 121. HBV from both child and mother had an unusual substitution at residue 118 and seemed to be of the ayw subdeterminant.

Cytotoxic T lymphocyte responses and CTL epitope escape mutation in HBsAg, anti-HBe positive individuals

BACKGROUND/AIMS

Clearance of hepatitis B virus (HBV) is characterised by a strong cytotoxic T cell response. Persistence of HBV in chronic hepatitis B carriers may be related to failure of this response. The aim of this study was to determine whether HLA class I restricted cytotoxic T lymphocyte (CTL) responses persist in anti-hepatitis B e (HBe) positive / HBV DNA negative individuals, and to correlate the presence of viral CTL epitope mutation with clinical outcome.

METHODS

An HLA/HBV dual transfectant model was used to demonstrate these CTL responses in individuals chronically infected with HBV. Subsequently, a known hepatitis B core (HBc) CTL epitope was sequenced in a family of five chronically infected individuals all sharing a HLA allele (HLA-A68.1).

RESULTS

Low level HLA class I restricted cytotoxic T cell responses were detected in the peripheral blood of five of eight anti-HBe positive individuals. In the family of HLA-A68.1 positive chronically infected individuals, mutation of the HLA-A68.1 restricted hepatitis B core antigen (HBcAg) CTL epitope STLPETTVVRR was found in all four anti-HBe positive individuals but not in the sole hepatitis B e antigen (HBeAg) positive patient.

CONCLUSION

These data are consistent with a continued immune selection pressure on HBV in anti-HBe positive chronically infected individuals with low replicating HBV infection and suggest that mutation of a CTL epitope may be a consequence of the immune response, as opposed to the cause of viral persistence.

The complete sequence of hepatitis E virus genotype 4 reveals an alternative strategy for translation of open reading frames 2 and 3

Isolates of hepatitis E virus (HEV) have recently been described from China that are distinct from Burmese, Mexican and US viruses and constitute a novel genotype (genotype 4). Here, the complete genomic sequence of a representative isolate of genotype 4 HEV, amplified directly from the stool of an acutely infected patient, is presented. Analysis of the entire sequence confirms our previous conclusion, based upon partial sequence data, that these Chinese isolates belong to a novel genotype. Typical of genetic variation in HEV, most nucleotide substitutions occur in the third base of the codon and do not affect the amino acid sequence. The genotype 4 virus is unusual in that a single nucleotide insertion in the ORF 3 region changes the initiation of ORF 3, and perhaps also ORF 2. The consequences of these changes are discussed.

Histidine-tagged ubiquitin substitutes for wild-type ubiquitin in Saccharomyces cerevisiae and facilitates isolation and identification of in vivo substrates of the ubiquitin pathway

A general method for purification of any substrate of the ubiquitin pathway, the major eukaryotic proteolytic pathway, should utilize the common characteristic of covalent linkage of ubiquitin to substrate lysyl residues. The utility of a N-terminal histidine-tagged ubiquitin (HisUb) for in vivo conjugation and isolation of ubiquitinated proteins by metal chelation chromatography is conditioned by the requirement that HisUb conjugate to the same set of proteins as wild-type ubiquitin. Stringent in vivo tests with Saccharomyces cerevisiae strains expressing ubiquitins only from plasmids were performed to show that HisUb could substitute for wild-type ubiquitin. The utility of HisUb as a method for purification of proteins ubiquitinated in vivo was demonstrated by metal chelation chromatography of yeast extracts expressing HisUb and immunoblotting for Rpb1, the largest subunit of RNA polymerase II. A fraction of Rpb1 was present in the ubiquitinated form in vivo. The ability to use HisUb expression in transgenic organisms that retain expression of their endogenous ubiquitin genes was demonstrated through transgenic Arabidopsis thaliana expressing HisUb or its variant HisUbK48R. UbK48R is a version of ubiquitin capable of conjugation to proteins, but cannot serve as an attachment site for ubiquitin via the major in vivo interubiquitin linkage. Whereas transgenic plants expressing HisUb showed insignificant enrichment of ubiquitinated proteins, transgenic Arabidopsis lines expressing HisUbK48R gave a much better yield.

Unusual hepatitis B surface antigen variation in a child immunised against hepatitis B

Perinatal transmission of and infection with hepatitis B (HBV) in early childhood are observed in a small proportion of the offspring of hepatitis B surface antigen (HBsAg)-positive mothers who are vaccinated against HBV immediately after giving birth. The children may be infected by wild-type HBV or by variants with amino acid substitutions in the "a" determinant of HBsAg, particularly at position 145 and, rarely, at positions 120, 126, 129, 131, 141, and 144. Four hundred and forty-six newborn infants of HBsAg-positive mothers in the northeastern part of the Czech Republic received combined active and passive immunisation against HBV. Only one child became an HBsAg carrier. This followed a mild, acute HBV illness in the beginning of the second year of his life. HBV DNA encoding the "a" determinant and surrounding region of HBsAg was sequenced after amplification from the plasma of the child and his mother. The child was infected with variants of HBsAg with substitutions at residues 137 and 139. The virus of the mother had changes at residues 120 and 121. HBV from both child and mother had an unusual substitution at residue 118 and seemed to be of the ayw subdeterminant.

Incomplete cement mantles in the sagittal femoral plane: an anatomical explanation

The influence of operative technique on the formation of incomplete cement mantles in the sagittal plane has been rarely considered in the literature. In this article, we discuss the influence of the anatomy of the proximal femur on the formation of incomplete cement mantles and discuss how their incidence can be reduced by correct component positioning.

Functional analysis of mutations conferring lamivudine resistance on hepatitis B virus

Two patterns of mutation are commonly observed in the polymerase gene of lamivudine [(-)2'-deoxy-3'-thiacytidine]-resistant hepatitis B virus (HBV). The M539I substitution in the conserved YMDD motif occurs independently of other changes, whereas the M539V substitution is associated with an additional upstream change (L515M). These mutations were introduced into a common background and their effects on HBV DNA replication and lamivudine resistance studied. The L515M and M539V mutations provided only partial resistance while the M539I mutation conferred a high degree of lamivudine resistance. The combination of the L515M and M539V mutations gave an intermediate level of replication competence, compared with either mutation alone, and increased resistance to lamivudine. This probably accounts for these two mutations always being observed together. The M539I mutation reduced replication competence.

A divergent genotype of hepatitis E virus in Chinese patients with acute hepatitis

Recent studies have reported and provided nucleotide sequence data from divergent isolates of hepatitis E virus (HEV), including isolates from North America and Africa. Sera were investigated from 29 Chinese patients with a diagnosis of acute hepatitis and who were negative for hepatitis viruses A-E by serology (HEV was excluded by testing for IgG antibody only). To determine whether some patients were infected with HEV but had yet to seroconvert to antibody positivity, RT-PCR was carried out with primers designed within conserved sequences of the HEV open reading frame (ORF) 1 and ORF2 regions. Fifteen patients were found to harbour sequences related to HEV. Analysis of the HEV products revealed that nucleotide sequences from nine of the sera closely matched Burmese-like HEV sequences (more than 92% nucleotide identity across ORF1 and 88% in ORF2). The remaining six HEV isolates were similar to each other but divergent from all other known HEV sequences (74 to 83% nucleotide identity in ORF1 or ORF2). Phylogenetic analysis suggests that the six divergent isolates represent a fourth genotype of HEV, distinct from the previously described Burmese, Mexican and United States variants (genotypes 1, 2 and 3). This novel variant, referred to here as the Chinese genotype (genotype 4), may be responsible for a significant proportion of cases of acute hepatitis in China, as seen by the fact that 40% of the HEV-infected patients in this study were genotype 4 positive.

A retrospective epidemiology study of contact eczema among the elderly attending a tertiary dermatology referral centre in Singapore

AIM

The aim of this study was to examine the epidemiology of contact eczema in the elderly patients attending a skin clinic in Singapore.

METHODOLOGY

This is a retrospective study on patients attending our skin clinic at the National Skin Centre. All patients older than 49 years old attending our Contact and Occupational Dermatoses Clinic between 1990 and 1993 were included in the study. The prevalence of contact eczema among different age groups (50-59 years, 60-69 years, and 70-79 years) were compared. Diagnosis of contact dermatitis was based on the clinical history, physical examination and relevant patch test reactions. Demographic data of the patients were collected and analysed. Chi-square test was used for statistical analysis.

RESULTS

Two hundred and one patients who were older than 49 years old, were included in the study. There was no significant difference in the prevalence of personal history of atopy among the 3 age groups. There was no significant difference in the racial distribution of the 3 age groups. The proportion of patients who were occupationally active decreased with age (50% vs 23% vs 0% respectively). There was no significant difference in the proportion of patients with positive patch test reactions in the 3 age groups although the proportion appears to increase with age (68% vs 75% vs 75% respectively). Similarly, the proportion of patients with allergic contact dermatitis was slightly higher in the older age group although the difference was not statistically significant among the 3 age groups (32% vs 45% vs 39% respectively). The face (54%) and hands (31%) were the commonest sites of eczema in the younger age group (50-59 years age group) whereas the lower limbs (41%) and the upper limbs (33.3%) were the commonest sites of eczema in the older patients (70-79 years age group). Nickel allergy was significantly more common in the younger age group (23% vs 17% vs 14% respectively). Medicament allergy (clioquinol-mix) and medicament related allergens e.g. balsam of Peru and fragrance-mix and para-phenylenediamine were slightly more prevalent in the older patients.

CONCLUSIONS

The findings appear to indicate that the prevalence of allergic contact dermatitis is higher in older patients and that contact dermatitis tends to occur on the extremities in older patients than younger patients.

White-centred retinal haemorrhages (Roth spots)

Roth spots (white-centred retinal haemorrhages) were classically described as septic emboli lodged in the retina of patients with subacute bacterial endocarditis. Indeed many have considered Roth spots pathognomonic for this condition. More recent histological evidence suggests, however, that they are not foci of bacterial abscess. Instead, they are nonspecific and may be found in many other diseases. A review of the histology and the pathogenesis of these white-centred haemorrhages will be provided, along with the work-up of the differential diagnosis.

HBV core promoter mutations prevail in patients with hepatocellular carcinoma from Guangxi, China

The development of primary liver cancer frequently is associated with persistent HBV infection, and tumours may arise in individuals who are anti-HBe positive. However, it is unclear whether viruses with an HBeAg-negative phenotype are associated with tumour development or are selected, during seroconversion, after chromosomal integration of wild-type viral DNA. In order to investigate the temporal evolution of the HBV genome in such individuals, the polymerase chain reaction was used to amplify HBV DNA from tumour tissue and serum of 14 patients from Guangxi, China with hepatocellular carcinoma. Comparison of nucleotide and amino acid sequences of the precore and proximal core region of HBV from the two sites in each patient produced evidence of divergence following integration in the tumour, but in most cases, HBeAg-negativity could not be explained by precore mutations. Sequences from the core promoter region were therefore examined and mutations were found in the majority, which are believed to upregulate transcription of the core (and pregenomic) RNA but to downregulate precore mRNA. To determine whether this finding merely reflected sequence variation among geographical isolates of HBV, the same region of HBV DNA from asymptomatic controls was sequenced and these mutations were found to be rare. We hypothesise that HBV with the core promoter mutations replicates at higher levels than the wild type, with the consequence that more integrations occur into the hepatocyte chromosomes during the early stages of infection. These hepatocytes may expand clonally and be targets for further mutagenic events leading to tumour development.

Double-evoked otoacoustic emissions. II. Intermittent noise rejection, calibration and ear-canal measurements

Measurements of double-click-evoked otoacoustics emissions (2CEOAEs) and double-chirp distortion products (2ChDPs) are reported for normal-hearing adults based upon theory presented in an earlier report [Keefe, J. Acoust, Soc. Am. 103, 3489-3498 (1998)]. The nonlinear acoustic response of a probe assembly used in ear-canal measurements in tested in a calibration cavity to compare the double-evoked (2E) technique with existing OAE techniques. The 2E technique reduces the peak distortion by approximately 30 dB relative to existing click-evoked techniques. The 2E subtraction of click responses is partially analogous to current techniques in that the linear response is eliminated, but differs in that high-frequency measurements are improved by eliminating time gating of the cochlear response, and low-frequency measurements are improved by reducing probe distortion, especially when two acoustic sources are used. Because time gating is eliminated, it is straightforward to measure the onset of a click-evoked OAE. The nonlinear coherence function is used to measure the nonlinear distortion signal-to-noise ratio (DNR) for the 2ChDPs and 2CEOAEs. The DNR is typically 20-30 dB. An intermittent noise rejection technique is implemented in real time that compares a currently acquired ear-canal response with a stored response. Dissimilar responses indicate the presence of intermittent noise, and the noise-contaminated responses are thereby discarded before ensemble averaging.

Engineering in vivo instability of firefly luciferase and Escherichia coli beta-glucuronidase in higher plants using recognition elements from the ubiquitin pathway

The ubiquitin pathway targets proteins for degradation through the post-translational covalent attachment of the 76 amino acid protein ubiquitin to epsilon-amino lysyl groups on substrate proteins. Two instability determinants recognized by the ubiquitin pathway in Saccharomyces cerevisiae have been identified. One is described by the N-end rule and requires specific destabilizing residues at the substrate protein N-termini along with a proximal lysyl residue for ubiquitin conjugation. The second is a linear uncleavable N-terminal ubiquitin moiety. The ability of these two determinants to function in higher plants was investigated in tobacco protoplast transient transfection assays using DNA encoding variants of well characterized reporter enzymes as substrates: firefly luciferase that is localized to peroxisomes (pxLUC), a cytosolic version of LUC (cLUC), and Escherichia coli beta-glucuronidase (GUS). cLUC with phenylalanine encoded at its mature N-terminus was 10-fold less abundant than cLUC with methionine at its mature N-terminus. GUS with phenylalanine encoded at its mature N-terminus was 3-fold less abundant than GUS with methionine at its mature N-terminus. The presence of a uncleavable N-terminal ubiquitin fusion resulted in 50-fold lower protein accumulation of cLUC, but had no effect on GUS. Both instability determinants had a much larger effect on cLUC than on pxLUC, suggesting that these degradation signals are either unrecognized or poorly recognized in the peroxisomes.

Energy reflectance in the ear canal can exceed unity near spontaneous otoacoustic emission frequencies

There is some controversy in the literature over whether the so-called "active mechanism" or "cochlear amplifier" is actually a power amplifier that can produce an output signal with more power than its input, or whether it simply minimizes dissipative losses within the cochlea without providing an actual power gain greater than unity. A corollary of this controversy is whether spontaneous otoacoustic emissions (SOAEs) represent the output of a nonlinear oscillator mechanism, i.e., a power amplifier which can produce an oscillatory output signal in the absence of an input oscillatory signal, or whether they represent the output of a noise-driven, passive, nonlinear system. This paper describes measurements of energy reflectance, and acoustic impedance in the ear canals of human subjects with strong SOAEs. The reflectance, and the resistive and reactive parts of the acoustic impedance, all show a frequency fine structure which correlates with SOAE frequencies, and which becomes more pronounced at low stimulus levels. In some ears at some SOAE frequencies, energy reflectance exceeds unity, and correspondingly, acoustic resistance is negative. This result demonstrates that there is a power gain at these frequencies: The power reflected from the cochlea to the ear canal exceeds the power incident. It is also consistent with the theory that these SOAEs are produced by a nonlinear oscillator mechanism in the cochlea.

Production of hepatitis B virus covalently closed circular DNA in transfected cells is independent of surface antigen synthesis

Covalently closed circular DNA (cccDNA) is the first hepatitis B virus (HBV) DNA replicative intermediate formed from the genomic DNA and serves as the template for synthesis of viral mRNA and pregenomic RNA. It also appears to be produced by intracellular recycling of relaxed circular DNA intermediates. Here, we report that none of the forms of HBV surface antigen affect this intracellular recycling of HBV DNA. Elimination of the initiation codons for the large and middle surface proteins did not affect the detection of surface antigen in culture supernatants. In contrast, detection of surface antigen was eliminated by the removal of, or the introduction of two stop codons downstream of, the initiation codon of the small (major) surface antigen. None of the mutations affected the production, in transfected HepG2 cells, of HBV DNA replicative intermediates, including cccDNA.

Selection of mutations in the hepatitis B virus polymerase during therapy of transplant recipients with lamivudine

We describe mutations in the hepatitis B virus (HBV) polymerase gene in viruses which reactivated in two patients during therapy with -2'-deoxy-3'-thiacytidine, or lamivudine (3TC), and following orthotopic liver transplantation for chronic hepatitis B. Virus resistance to 3TC is associated with mutations which lead to amino acid substitutions in the highly conserved tyr-met-asp-asp (YMDD) motif, part of the active site of the polymerase, and which parallel those seen in resistant human immunodeficiency virus (HIV). Substitutions of valine and isoleucine for methionine were found in the two cases. The significance of single secondary mutations, which differ between viruses from the two patients, remains to be determined. Thus, viral resistance to lamivudine of hepatitis B virus mimics that of HIV and can occur in the setting of immunosuppression after liver transplantations.

Sequence of the nucleocapsid protein gene of subgroup A and B avian pneumoviruses

The nucleocapsid protein (N) gene of two subgroup A and one subgroup B strains of avian pneumovirus has been cloned and sequenced. The gene of all three isolates comprised 1197 nucleotides (nt), which formed a single major open reading frame, potentially encoding a protein of 391 amino acid residues. The N gene of the two subgroup A isolates differed by only 1 nt but differed by 282 (24%) nt and 35 (11%) amino acids from the B isolate. The predicted protein was identical in length to that of human, bovine and ovine respiratory syncytial viruses, the amino acid identity being approximately 41% overall but with some regions of identity > 90%.

Case report: malignant fibrous histiocytoma following radiation therapy of fibrous dysplasia

Malignant fibrous histiocytoma commonly occurs spontaneously. In some cases it follows previous therapeutic or incidental irradiation, or miscellaneous pre-existing osseous conditions. Recently, it has been associated with total hip arthroplasty. We report a case of malignant fibrous histiocytoma following radiation therapy of fibrous dysplasia and review the relevant literature.

Sequence and in vitro expression of the phosphoprotein gene of avian pneumovirus

The phosphoprotein (P) gene of two subgroup A strains of avian pneumovirus comprised 855 nucleotides containing only one substantial open reading frame encoding a protein of 278 amino acids, with a predicted M(r) of 30,323. In vitro translation of P mRNA in a wheat germ system resulted in the synthesis of two polypeptides of M(r) 35,000. Comparison of the deduced P protein sequence with that of the known mammalian pneumoviruses revealed overall amino acid identities ranging from 31 to 34.5%, suggesting a distant relationship. However, there was a much higher identity (63.2-68.4%) in a region of 57 residues, which included a heptad repeat sequence.

Use of single-cysteine mutants to probe the location of the disulfide bond in LamB protein from Escherichia coli

The two cysteine residues of the LamB protein of Escherichia coli outer membrane have been shown to form an intrasubunit disulfide whose location differs greatly in the two current topology models of the LamB protein. This study probes the location of the disulfide by examining conditions for intersubunit disulfide formation in single-cysteine mutants of LamB protein. Formation of an intersubunit bond in the purified mutant proteins, which resulted in a disulfide-linked dimer, only occurred after heat treatment, suggesting the disulfide is not exposed on the surface in the native protein.

Sequence analysis of the 22K, SH and G genes of turkey rhinotracheitis virus and their intergenic regions reveals a gene order different from that of other pneumoviruses

The nucleotide and deduced amino acid sequences of three genes of turkey rhinotracheitis virus (TRTV) together with the nucleotide sequences of the relevant intergenic regions were determined. The deduced amino acid sequence of one of the genes shows significant identity (42%) to that of the 22K protein of human respiratory syncytial virus (RSV). The TRTV 22K gene, like that of RSV, has a second open reading frame, although the amino acid sequence deduced from this reading frame does not show any similarity to the equivalent predicted RSV protein. The other two genes and their deduced amino acid sequences do not show any sequence similarity to the genes of other pneumoviruses. However, the hydrophobicity profiles of the predicted proteins do show similarities to those of the small hydrophobic (SH) and attachment protein (G) genes of RSV. The TRTV G gene is 1193 nucleotides in length and encodes a protein of 391 amino acids (M(r) 42984), which is rather larger than the RSV G protein (predicted M(r) 36000). The TRTV SH gene is 589 nucleotides in length, encoding a protein of 174 amino acids (M(r) 18797), which is considerably larger than the size of the RSV SH protein (M(r) 7500). The sequences of the intergenic regions derived from clones of polycistronic mRNAs and polymerase chain reaction products obtained with primers from different genes reveal the order on the virus genome to be 3' F-22K-SH-G 5'. This differs from the gene order of paramyxoviruses and morbilliviruses, which lack a 22K gene (and in some cases a SH gene), and the pneumoviruses RSV and pneumonia virus of mice, which have the F and 22K genes located after the G gene.