Cell-Free Synthesis of Factor VIII Related Protein

Polyadenylated ribonucleic acid (RNA) was isolated from confluent human endothelial cells in culture and translated in a cell-free rabbit reticulocyte lysate protein-synthesizing system. Using specific immunopredpitation, the translation product was found to contain 1.58% VIH related protein (VIIIR), which has a molecular weight of 0.26 × 106, similar to the subunit of VIIIR present in normal plasma. This indicated that VIIIR messenger RNA is responsible for the synthesis of subunits only and intracellular post-translational events are required for the assembly of tetramer and multimers.

Characterization of Factor VIII Related Protein Synthesized by Human Endothelial Cell: A Study of Structure and Function

Crossed immunoelectrophoresis showed that factor VIII related protein (VIII R) synthesized in the human endothelial cell (EC-VIII R) had faster electrophoretic mobility than that secreted into the culture medium (MED-VIII R). Sodium dodecyl sulphate agarose gel electrophoresis followed by radioimmunofixation showed that EC-VIII R consisted of molecules varying from 0.26 × 106 to 3.76 × 106 daltons while MED-VIII R had molecules ranging from 0.93 × 106 to greater than 10 × 106 daltons, similar to that present in plasma. The smallest VIII R molecule present in normal plasma or spent culture medium (0.93 × 106 daltons) corresponded to a tetramer of subunits of 0.22-0.24 × 106 daltons. Only molecular forms greater than 3.76 × 106 daltons possessed ristocetin cofactor activity. Sonication (15 μ. amplitued for 30 secs) effectively broke the non-covalent bonds of the VIII R multimers resulting in smaller molecules. Thus endothelial cells in culture synthesized VIII R subunits and assembled them into the higher multimeric forms on secretion. Different types of von Willebrand disease could result from defects of either of the two processes.

The Effect of Oral Contraceptives on Coagulation and Fibrinolytic Parameters in the Chinese – A Prospective Study

Thirty-two Chinese and 7 Caucasians were studied prospectively for 12 months for the effects of oral contraceptives (OC) on certain coagulation and fibrinolytic parameters. In both ethnic groups there was an increase in α1 antitrypsin level. There was no significant change in antithrombin III concentration measured either by radioimmunoassay (At-III-RIA) or chromogenic assay (anti Xa-chromogenic) in the Chinese, but a significant decrease in anti Xa-chromogenic at 7 months and At-III-RIA at 12 months in the Caucasians. Also, α2 plasmin inhibitor (α2PI) levels were unchanged in the Chinese but a significant increase occurred in the Caucasians at 12 months. Enhanced fibrinolytic response to venous occlusion was demonstrated in the Chinese at 12 months but not in the Caucasians.

Antithrombin III, the Major Modulator of Intravascular Coagulation, Is Synthesized by Human Endothelial Cells

Human endothelial cells in culture is shown to synthesize antithrombin III (At-III). The endothelial cell At-III(EC-At-III) consists of a small fraction similar to plasma At-III and a larger fraction with decreased heparin-binding as tested by crossed immunoelectrophoresis. However, both the anti-Xa and thrombin-neutralizing activities of the EC-At-III were rapid and active even in the absence of added heparin. It is concluded that the major portion was probably bound to endogenous heparin-like substance, thus accounting for its decreased exogenous heparin binding. The presence of At-III and other antithrombotic factors in the vascular endothelium offer protection against thrombosis and possibly atherosclerosis.

The origin of ultra diffuse galaxies: stellar feedback and quenching

We test if the cosmological zoom-in simulations of isolated galaxies from the FIRE project reproduce the properties of ultra diffuse galaxies (UDGs). We show that outflows that dynamically heat galactic stars, together with a passively aging stellar population after imposed quenching, naturally reproduce the observed population of red UDGs, without the need for high spin haloes, or dynamical influence from their host cluster. We reproduce the range of surface brightness, radius, and absolute magnitude of the observed red UDGs by quenching simulated galaxies at a range of different times. They represent a mostly uniform population of dark matter-dominated dwarf galaxies with M * ~ 108 M☉, low metallicity, and a broad range of ages; the more massive the UDGs, the older they are. The most massive red UDG in our sample(M * ~ 3 × 108 M☉) requires quenching at z ~ 3 when its halo reached M h ~ 1011M☉. Our simulated UDGs form with normal stellar-to-halo ratios and match the central enclosed masses and the velocity dispersions of the observed UDGs. Enclosed masses remain largely fixed across a broad range of quenching times because the central regions of their dark matter haloes complete their growth early. If our simulated dwarfs are not quenched, they evolve into bluer low surface brightness galaxies with M/L similar to observed field dwarfs. While our simulation sample covers a limited range of formation histories and halo masses, we predict that UDG is a common, and perhaps even dominant, galaxy type around M * ~ 108 M☉, both in the field and in clusters.

Gas kinematics in FIRE simulated galaxies compared to spatially unresolved HI observations

The shape of a galaxy's spatially unresolved, globally integrated 21-cm emission line depends on its internal gas kinematics: galaxies with rotationally supported gas discs produce double-horned profiles with steep wings, while galaxies with dispersion-supported gas produce Gaussian-like profiles with sloped wings. Using mock observations of simulated galaxies from the FIRE project, we show that one can therefore constrain a galaxy's gas kinematics from its unresolved 21-cm line profile. In particular, we find that the kurtosis of the 21-cm line increases with decreasing V/σ and that this trend is robust across a wide range of masses, signal-to-noise ratios, and inclinations. We then quantify the shapes of 21-cm line profiles from a morphologically unbiased sample of ~2000 low-redshift, HI-detected galaxies with Mstar = 107-11 M☉ and compare to the simulated galaxies. At Mstar ≳ 1010 M☉, both the observed and simulated galaxies produce double-horned profiles with low kurtosis and steep wings, consistent with rotationally supported discs. Both the observed and simulated line profiles become more Gaussian like (higher kurtosis and less-steep wings) at lower masses, indicating increased dispersion support. However, the simulated galaxies transition from rotational to dispersion support more strongly: at Mstar 108-10 M, most of the simulations produce more Gaussian-like profiles than typical observed galaxies with similar mass, indicating that gas in the low-mass simulated galaxies is, on average, overly dispersion supported. Most of the lower-mass-simulated galaxies also have somewhat lower gas fractions than the median of the observed population. The simulations nevertheless reproduce the observed line-width baryonic Tully-Fisher relation, which is insensitive to rotational versus dispersion support.

New Era of CPR: Application of I-Technology in Resuscitation

Introduction

The present study evaluated the performance and acceptance of a cardiopulmonary resuscitation (CPR) feedback application for the iPhone (“PocketCPR®”) designed to improve chest compression performance.

Methods

We randomly assigned participants into two groups to perform chest compression with (study group) or without (control group) using the “PocketCPR®” on a manikin. The participants performed totally four sets of chest compression simulating two CPR scenarios. In the first scenario, no advanced airway was inserted while in the second scenario, advanced airway was inserted. We measured and compared the rate and depth of chest compression between the groups in both scenarios. Participants in study group also finished a questionnaire on the use of feedback application.

Results

The mean compression depth of the study group was significantly deeper both in the first scenario (5.22 cm; 4.56 cm, p=0.002; 5.30 cm; 4.56 cm, p=0.001) and the second scenario (5.34 cm; 4.56 cm, p<0.001; 5.35 cm; 4.49 cm, p<0.001). However, the mean compression rate of study group was significantly slower than the control group both in the first scenario (105.19; 118.58, p<0.001; 105.23; 119.36, p<0.001) and the second scenario (106.10; 121.08, p<0.001, 106.61; 117.42, p=0.002).

Conclusion

A mobile phone feedback application “PocketCPR®” improves chest compression quality by increasing the compression depth in laboratory setting. Further study is indicated to demonstrate its benefit in clinical setting.

Low-dose subcutaneous alemtuzumab is a safe and effective treatment for chronic acquired pure red cell aplasia

Three patients with pure red cell aplasia, with or without co-existing large granular lymphocytic leukaemia, who remained transfusion-dependent despite treatment with established first-line therapy, were treated with low-dose subcutaneous alemtuzumab 15 mg twice to thrice per week, for 3 to 4 weeks. The mean response time was 17 days compared with a response time of at least 61 days on standard first-line therapy. There were no serious side-effects and the mean duration of remission was 13 months. Low-dose subcutaneous alemtuzumab is a safe and effective treatment for pure red cell aplasia and further trials should be conducted to compare the long-term effectiveness of this treatment with conventional therapy.

Synthesis of embedded Au nanostructures by ion irradiation: influence of ion induced viscous flow and sputtering

The ion-irradiation induced synthesis of embedded Au nanoparticles (NPs) into glass from islands of Au on a glass substrate is studied in the context of recoiling atoms, sputtering and viscous flow. Cross sectional transmission electron microscopy studies revealed the formation of Au NPs embedded in the glass substrates by the 50 keV Si(-) ion irradiation of irregularly shaped Au nanostructures on the glass surfaces at a fluence of 3 × 10(16) ions/cm(2). The depth profiles of Au in the samples were obtained from high-resolution Rutherford backscattering spectrometry studies. The results from TRIDYN simulation reveal the role of various ion-induced processes during the synthesis of the embedded Au NPs, viz. sputtering and recoiling atoms. Simulation and experimental results suggest that the viscous flow is one of the major factors that are responsible for the embedding of Au nanoparticles into the glass substrate.

Andrographolide protects against cigarette smoke-induced oxidative lung injury via augmentation of Nrf2 activity

BACKGROUND AND PURPOSE

Cigarette smoke is a major cause for chronic obstructive pulmonary disease (COPD). Andrographolide is an active biomolecule isolated from the plant Andrographis paniculata. Andrographolide has been shown to activate nuclear factor erythroid-2-related factor 2 (Nrf2), a redox-sensitive antioxidant transcription factor. As Nrf2 activity is reduced in COPD, we hypothesize that andrographolide may have therapeutic value for COPD.

EXPERIMENTAL APPROACH

Andrographolide was given i.p. to BALB/c mice daily 2h before 4% cigarette smoke exposure for 1h over five consecutive days. Bronchoalveolar lavage fluid and lungs were collected for analyses of cytokines, oxidative damage markers and antioxidant activities. BEAS-2B bronchial epithelial cells were exposed to cigarette smoke extract (CSE) and used to study the antioxidant mechanism of action of andrographolide.

KEY RESULTS

Andrographolide suppressed cigarette smoke-induced increases in lavage fluid cell counts; levels of IL-1β, MCP-1, IP-10 and KC; and levels of oxidative biomarkers 8-isoprostane, 8-OHdG and 3-nitrotyrosine in a dose-dependent manner. Andrographolide promoted inductions of glutathione peroxidase (GPx) and glutathione reductase (GR) activities in lungs from cigarette smoke-exposed mice. In BEAS-2B cells, andrographolide markedly increased nuclear Nrf2 accumulation, promoted binding to antioxidant response element (ARE) and total cellular glutathione level in response to CSE. Andrographolide up-regulated ARE-regulated gene targets including glutamate-cysteine ligase catalytic (GCLC) subunit, GCL modifier (GCLM) subunit, GPx, GR and heme oxygenase-1 in BEAS-2B cells in response to CSE.

CONCLUSIONS

Andrographolide possesses antioxidative properties against cigarette smoke-induced lung injury probably via augmentation of Nrf2 activity and may have therapeutic potential for treating COPD.

Anti-allergic action of anti-malarial drug artesunate in experimental mast cell-mediated anaphylactic models

BACKGROUND

Allergy is an acquired hypersensitivity reaction of the immune system mediated by cross-linking of allergen-specific IgE-bound high-affinity IgE receptors, leading to immediate mast cell degranulation. Artesunate is a semi-synthetic derivative of artemisinin, an active component of the medicinal plant Artemisia annua. Artesunate is a clinically effective anti-malarial drug and has recently been shown to attenuate allergic asthma in mouse models. This study investigated potential anti-allergic effects of artesunate in animal models of IgE-dependent anaphylaxis.

METHODS

Anti-allergic actions of artesunate were evaluated in passive cutaneous anaphylaxis and passive systemic anaphylaxis mouse models, and in ovalbumin-induced contraction of bronchial rings isolated from sensitized guinea pigs. Direct mast cell-stabilizing effect of artesunate was examined in RBL-2H3 mast cell line and in mature human cultured mast cells. Anti-allergic signaling mechanisms of action of artesunate in mast cells were also investigated.

RESULTS

Artesunate prevented IgE-mediated cutaneous vascular hyperpermeability, hypothermia, elevation in plasma histamine level, and tracheal tissue mast cell degranulation in mice in a dose-dependent manner. In addition, artesunate suppressed ovalbumin-mediated guinea pig bronchial smooth muscle contraction. Furthermore, artesunate concentration-dependently blocked IgE-mediated degranulation of RBL-2H3 mast cells and human culture mast cells. Artesunate was found to inhibit IgE-induced Syk and PLCγ1 phosphorylation, production of IP(3) , and rise in cytosolic Ca(+2) level in mast cells.

CONCLUSIONS

We report here for the first time that artesunate possesses anti-allergic activity by blocking IgE-induced mast cell degranulation, providing a foundation for developing artesunate for the treatment of allergic asthma and other mast cell-mediated allergic disorders.

Antineutrophil cytoplasmic antibodies in chronic idiopathic intraocular inflammatory disease

Antineutrophil cytoplasmic antibodies (ANCA) are found in the sera of patients with Wegener's granulomatosis and other systemic necrotising vasculitides. Antibody levels correlate closely with disease activity so that follow-up of ANCA titres might be helpful in guiding therapy. The authors assessed in a cohort of patients with chronic ocular inflammatory disease ANCA titres prospectively over a two-year period, by an indirect immunofluorescent technique. They found that sera from 10/64 patients (15.6%) stained positive for c-ANCA antibodies, and none stained for p-ANCA. Six c-ANCA positive patients had one or more clinical relapses (range one to three) during this study period. Each relapse correlated with a rise in ANCA titre. The remaining four patients who were found to have persistently low titres of c-ANCA had no clinical relapses. The authors conclude that although c-ANCA is only present in a small proportion of patients with idiopathic chronic intraocular inflammatory disease, the ANCA titre may be used to monitor disease activity in this group of patients. Further study to assess the potential of c-ANCA titres in predicting disease relapse is indicated, which in the future may minimise the side effects of currently used immunosuppressive therapies.

Detection of paternal alleles in maternal plasma for non-invasive prenatal diagnosis of beta-thalassemia: a feasibility study in southern Chinese

OBJECTIVE

To evaluate in maternal plasma, the efficacy of detecting the paternal beta-gene mutation and informative single nucleotide polymorphisms (SNPs) linked to the paternal-mutant or -normal allele in non-invasive prenatal diagnosis (NIPND).

STUDY DESIGN

In 20 at-risk pregnancies, using the allele-specific arrayed primer extension (AS-APEX) technology of the previously published "Thalassemia" array, cyanine-5-deoxycytosine triphosphate (Cy5-dCTP) was incorporated into the extended strands to matched PCR-amplified maternal plasma DNA templates, to detect both the paternal beta-gene mutation and informative paternal SNPs.

RESULTS

Sensitivity experiment showed that 5pg DNA as starting template gave detectable signals on the array. In 13 cases (65%), the paternal-derived beta-gene mutation and/or informative mutant-associated SNP were detected. A subsequent invasive procedure was required to determine if the fetus had a beta-thalassemia (thal) major or minor genotype. In 3 cases (15%), absence of the paternal mutant or mutant-associated SNP excluded a beta-thal major fetus; while in 4 cases (20%), this approach was non-discriminative as both parents carry the same mutation without any informative SNP.

CONCLUSION

This approach was useful in 16 out of 20 (80%) pregnancies at risk for beta-thal in southern Chinese.

Localization of hRad9 in breast cancer

Background

hRad9 is a cell cycle checkpoint gene that is up-regulated in breast cancer. We have previously shown that the mRNA up-regulation correlated with tumor size and local recurrence. Immunohistochemical studies were made to better define the role of hRad9 in breast carcinogenesis.

Methods

Localisation of hRad9 protein were performed on paired tumor and normal breast tissues. Immunoblotting with and without dephosphorylation was used to define the protein isolated from breast cancer cells.

Results

Increased hRad9 protein was observed in breast cancer cells nucleus compared to non-tumor epithelium. This nuclear protein existed in hyperphosphorylated forms which may be those of the hRad9-hRad1-hHus1 complex.

Conclusion

Finding of hyperphosphorylated forms of hRad9 in the nucleus of cancer cells is in keeping with its function in ameliorating DNA instability, whereby it inadvertently assists tumor growth.

Experience in preimplantation genetic diagnosis for exclusion of homozygous alpha degrees thalassemia

OBJECTIVE

To report our experience in preimplantation genetic diagnosis (PGD) for the exclusion of homozygous alpha degrees thalassemia.

PATIENTS AND METHODS

PGD was performed on nine couples with alpha degrees thalassemia genotype undergoing assisted reproduction. Oocytes were aspirated after ovarian stimulation and fertilized by intracytoplasmic sperm injection. One or two blastomeres were biopsied from the six- to eight-cell embryo. Single cell multiplex PCR of the normal and alpha degrees thalassemia alleles was performed for first round, followed by semi-nested PCR of the respective alleles using 5'-end labelled fluorescent primers. Only those embryos with a blastomere diagnosed as having at least one normal allele were selected for transfer.

RESULTS

One hundred and twenty-six blastomeres from 82 embryos were analyzed. The rates of allele dropout was 10.2% and PCR failure 12.7%. Fifty-eight embryos (70.7%) had at least one normal allele, of which 31 were transferred to 13 prepared cycles and one triplet pregnancy achieved. The triplets showed no ultrasound features of homozygous alpha degrees thalassemia at 18 weeks and were delivered in healthy condition by caesarean section at 34 weeks. Their genotypes were confirmed by cord blood analysis.

CONCLUSIONS

PGD for alpha degrees thalassemia is possible by single cell PCR. The transfer and successful implantation of unaffected embryos ensure birth of disease-free babies.

Functional outcome of the hand following flexor tendon repair at the 'no man's land'

PURPOSE

To evaluate the functional outcome of the hand following flexor tendon repair at 'no man's land' using 2 strands of a modified Kessler core suture and combined controlled motion rehabilitation protocol.

METHODS

Records of 31 zone-2 flexor tendon injuries in 21 digits of 16 patients between July 2000 and June 2005 were reviewed retrospectively. The injured tendons were repaired within 24 hours using 2 strands of a modified Kessler core suture, reinforced by a continuous circumferential epitendon suture. All patients completed a rehabilitation protocol that included active extension against a rubber band, passive flexion, and controlled passive extension and passive flexion exercises. Functional outcome of the fingers was assessed using the Buck-Gramcko II score. Hand grip strength, rehabilitation period, and rupture rate were also measured.

RESULTS

17 (81%) out of 21 digits in 15 out of 16 patients achieved an excellent-to-good functional grade. The remaining patient with concomitant injuries to 4 (19%) digits attained a poor functional grade, attributable to poor compliance with the rehabilitation protocol. The mean rehabilitation period was 130 days and the mean grip strength was 78% that of the uninjured side. Concomitant digital nerve injury did not adversely affect the final outcome. Only one (4.8%) patient experienced a rupture.

CONCLUSION

The surgical method and rehabilitation protocol used for zone-2 flexor tendon injury is safe and results in a reasonably good functional outcome.

A thalassaemia array for Southeast Asia

The alpha and beta thalassaemias are the commonest genetic disorders worldwide. The homozygous state is associated with high morbidity and mortality, thus screening of at-risk pregnancies and prenatal testing are strongly advocated. A thalassaemia (thal) array has been designed using allele-specific arrayed primer extension (AS-APEX) for the simultaneous analysis of 15 non-deletion alpha-gene defects and 23 beta-gene mutations commonly found in southeast Asian countries, where thalassaemias are highly prevalent. This overcomes the problem of using multiple reverse dot blot analysis. The array showed 100% sensitivity and specificity in the detection of 120 beta-thal mutants and 35 non-deletion alpha-thal mutants. It is robust enough to be produced in a single place and shipped to other laboratories for use. The production cost of the array is low, each slide can be used for three different test samples and is therefore amenable to large scale antenatal screening in southeast Asian countries.

Long-term survival of primary root canal treatment carried out in a dental teaching hospital

AIM

This study aimed to examine clinically and radiographically the survival of primary root canal treatment completed in a dental teaching hospital between 10 and 20 years previously.

METHODOLOGY

A data collection form was used to collate all information obtained from the written patients' records along with the results from clinical and radiographic examination of 608 teeth, out of a total of 986 randomly selected teeth that had been root filled in the Prince Philip Dental Hospital (PPDH), Hong Kong, between 1981 and 1989. The criteria for failure were extractions (except for documented nonendodontic reason), retreatments and presence of a periapical radiolucency. The survival function of the treated teeth was plotted against the calculated date of failure using the Kaplan-Meier (K-M) method. Covariables were examined further by Cox Regression analysis with a backward stepwise method.

RESULTS

A total of 314 teeth (52%) were either documented or deemed to have failed after examination. The median survival time was 111 months. Cox Regression analysis indicated that the survival of root-filled teeth was significantly influenced by the tooth type, preoperative periapical status and the type of coronal restoration. The survival function declined with time, with a rapid drop in the first 18 months or so. The rate at which failures occurred appeared to slow down with a longer observation time.

CONCLUSIONS

There was a nonlinear decline in the cumulative survival probability of primary root canal treatment. Tooth type, preoperative periapical status and type of post and final restoration significantly affected the long-term survival of the treated teeth.

Can defects in transferrin receptor 2 and hereditary hemochromatosis genes account for iron overload in HbH disease?

Iron overload was found to be the major cause of disability in Chinese HbH disease patients although they were not on regular blood transfusion. The transferrin receptor 2 (TFR2) and hereditary hemochromatosis (HFE) genes were examined to see if inheritance of these gene defects may be a possible cause of iron overload in 45 HbH patients. A novel intronic (IVS6 (+6) T-->A) mutation of the TFR2 gene was identified in one patient, and six others were found to carry a known missense mutation (exon 5, I238M) that was also present in one normal control subject. One HbH patient and one normal control carried the H63D mutation of the HFE gene. Since only eight out of 45 iron-overloaded HbH patients carry a defect in the TFR2 or HFE gene in the heterozygote state and their iron loading status was comparable to the matched controls without such defects, it would appear that the accumulation of excess iron in HbH disease is more likely a result of increase dietary absorption secondary to ineffective erythropoiesis.

Quantitative polymerase chain reaction for the rapid prenatal diagnosis of homozygous alpha-thalassaemia (Hb Barts hydrops fetalis)

A quantitative polymerase chain reaction (Q-PCR) method based on the TaqMan technology has been devised for the prenatal diagnosis of homozygous alpha*-thalassaemia (south-east Asian type deletion). Primers and TaqMan probes were designed to specifically amplify an alpha*-thal chromosomal fragment or a normal alpha-chromosomal fragment. Variations in input target DNA in individual sample wells were normalized by the simultaneous amplification of a beta-actin gene fragment and results expressed as a ratio to that of beta-actin. There was no overlap of the data between the homozygous alpha*-thal, alpha*-thal and normal subjects. Up to 5% maternal DNA (alpha*-thal) contamination did not affect the specificity of the result. In 31 prenatal diagnoses, the result using Q-PCR compared favourably with the gold standard of Southern hybridization of alpha-genes.

Autosomal dominant congenital superior oblique palsy

PURPOSE

We describe a mother and all her offspring with congenital superior oblique palsy (CSOP), and a father and all his sons with unilateral CSOP. We discuss the inheritance pattern in our pedigrees and compare it with previous reports.

METHOD

All available family members were examined. The prism cover test was performed. Ocular movements were examined in all positions of gaze and where possible a Hess chart plotted. Lang and TNO stereotests were used to determine the stereo-acuity. The results of these tests combined with the Bielschowsky head tilt test (BHTT) were used to confirm the diagnosis of superior oblique palsy. The condition was classified as congenital if it presented early based on history or the observation of old photographs and in the absence of a causative factor.

RESULTS

The affected members of family A consist of a father and his three sons with unilateral CSOP. His daughter had a mild weakness of her left inferior and superior rectus muscle. One of his sons was asymptomatic and only recognised on screening of the family for the study. The affected members of family B consist of a mother and her younger daughter with unilateral CSOP and her older daughter with bilateral CSOP. She had no other children.

CONCLUSIONS

Our families demonstrate what is probably an autosomal dominant form of CSOP. It is possible that hereditary CSOP is more common than previously reported.

Timing of postoperative adjustment in adjustable suture strabismus surgery

PURPOSE

The use of adjustable sutures in strabismus surgery has increased the rate of surgical success. Little data are available on the optimum timing for postoperative adjustment after strabismus surgery. We wanted to compare 2 common practices of adjustable suture technique after strabismus surgery.

METHODS

Two comparable groups of 40 patients each, who had strabismus surgery with adjustable suture technique, were prospectively studied. Group A had early adjustment the same day of the surgery about 6 hours after the operation, and group B had late adjustment the next day about 24 hours after the operation. Subjective scoring tables were used to evaluate the pain felt by the patient before, during, and after the adjustment and any difficulties of the adjustment process. Requirements of postoperative pain medications and final alignment 6 weeks after surgery were also compared.

RESULTS

Despite adequate statistical power, no significant differences were found between the groups regarding pain before, during, and after adjustment, difficulties performing the adjustment, and final alignment after 6 weeks (P > .05). Both adjustment schedules were equally associated with mild to moderate pain before, during, and after the adjustment. In the first 24 hours after surgery, no overall difference in the use of pain medications was found. Nausea and vomiting in the first 24 postoperative hours were more common in the early adjustment group (P = .02).

CONCLUSION

The surgeon can feel free to choose the timing for postoperative adjustment. However, when performing an early adjustment, the surgeon should be especially prepared to control nausea and vomiting.

Effect of storage conditions on calcium sulphate hemihydrate-containing products

OBJECTIVE

Dental gypsum products are liable to deterioration on exposure to the air because of reaction between calcium sulphate hemihydrate and water vapour. The purpose of this investigation was to refine the knowledge of the conditions and rates at which this occurred for a representative selection of such products with a view to improved storage recommendations.

MATERIALS AND METHODS

Absorption of water from controlled atmospheres (25-40 degrees C, 75-99% RH) was monitored gravimetrically for a dental artificial Stone, Plaster of Paris, an Impression plaster and a gypsum-bonded Investment.

RESULTS

An initial steady absorption stage was followed by a transition to a rapid absorption; this led to a completion stage as the presumed hydration reaction approached completion. The logarithm of time of the transition showed approximately linear dependence on the relative humidity (and not on water vapour pressure as might have been expected) and a slight but significant (P<0.005) negative dependence on temperature in the range 25-35 degrees C for Stone, Plaster of Paris and the Impression plaster, but not for the Investment (P>0.5). The behaviour for the first three materials at 40 degrees C departed significantly from the temperature-dependent trend (P<0.05) while the Investment showed no such effect. The absorption by the Investment was substantially faster than for the other materials.

SIGNIFICANCE

There is no evidence to suggest that there is a 'safe' humidity for exposure to the atmosphere although for the Stone and Plasters at RH <70% in excess of 1000 h is predicted to be necessary before rapid reaction commences. For the Investment, the equivalent time at 70% RH is 1d.

Indocyanine green angiography of the anterior segment in patients undergoing strabismus surgery

BACKGROUND

Anterior segment imaging using fluorescein angiography is only suitable in lightly pigmented irides as the brown pigmentation of the iris masks fluorescein transmission. Indocyanine green (ICG) angiography has excellent penetration of pigment epithelium and, therefore, has potential application in detecting perfusion changes of dark irides after strabismus surgery.

METHODS

A prospective study was conducted on patients older than 15 years undergoing strabismus surgery. A fundus camera was focused on the arteriolar tufts of the pupillary margin and 50 mg of ICG (concentration of 12.5 mg/ml) was given intravenously. Images were then obtained at 1 minute intervals of 5 minutes' duration.

RESULTS

45 patients with a mean age of 54.6 years and a mean follow up period of 8.6 weeks were studied. There were 23 patients in the primary surgery group, 11 in the secondary surgery group, and 11 in the staged group. Iris ICG angiograms were successfully performed in all patients. No persistent filling defect was detected in the primary and secondary horizontal recti surgery groups or in the secondary or staged vertical and combined vertical rectus groups 6-8 weeks postoperatively. 57% of both primary vertical and combined vertical and horizontal groups showed defects in the early postoperative phase. Only three cases demonstrated late perfusion defects in this series.

CONCLUSION

ICG can detect iris perfusion changes in dark irides after strabismus surgery. Iris reperfusion was achieved in the majority of the cases.

Single nucleotide polymorphisms of the factor IX gene for linkage analysis in the southern Chinese population

Carrier detection and prenatal testing for haemophilia B in Oriental populations have been hampered by the lack of informative markers within the factor IX (FIX) gene. We detected a T/C nucleotide variation at nucleotide 32770 in the poly-A region of the FIX gene in the mother of a haemophilia B child. Analysis of 139 unrelated alleles revealed a heterozygosity rate of 0.193, thus offering an additional marker for linkage analysis. Together with two other polymorphic sites (5' MseI and 3' HhaI) found in Chinese and Thai populations, these polymorphisms were useful in 66% of the families studied.

Genetic and clinical features of hemoglobin H disease in Chinese patients

BACKGROUND

Normally, one pair of each of the two alpha-globin genes, alpha1 and alpha2, resides on each copy of chromosome 16. In hemoglobin H disease, three of these four alpha-globin genes are affected by a deletion, a mutation, or both. We studied the alpha1-globin gene abnormalities and the clinical and hematologic features of Chinese patients with hemoglobin H disease in Hong Kong.

METHODS

We assessed the clinical features, hematologic values, serum ferritin levels, and liver function of 114 patients with hemoglobin H disease. We also performed echocardiography and magnetic resonance imaging of the liver and examined the two pairs of alpha-globin genes.

RESULTS

Hemoglobin H disease in 87 of the 114 patients (76 percent) was due to the deletion of three of the four alpha-globin genes (--/-alpha), a combination termed the deletional type of hemoglobin H. The remaining 27 patients (24 percent) had the nondeletional type of hemoglobin H disease, in which two alpha-globin genes are deleted and a third is mutated (--/alphaalphaT). All 87 patients with the deletional type of hemoglobin H were double heterozygotes in whom there was a deletion of both alpha-globin genes from one chromosome, plus a deletion of the alpha1 or alpha2 gene from the other chromosome (--/alpha- or --/-alpha). A variety of mutated alpha-globin genes was found in the patients with nondeletional type of hemoglobin H disease. Patients with the nondeletional type of the H disease had more symptoms at a younger age, more severe hemolytic anemia, and larger spleens and were more likely to require transfusions than patients with deletional hemoglobin H disease. The severity of iron overload was not related to the genotype.

CONCLUSIONS

Chinese patients in Hong Kong with the nondeletional type of hemoglobin H disease have more severe disease than those with the deletional type of the disease. Iron overload is a major cause of disability in both forms of the disease.

Endogenous bacterial endophthalmitis: an east Asian experience and a reappraisal of a severe ocular affliction

PURPOSE

To report 32 eyes of 27 patients with endogenous bacterial endophthalmitis seen over a 4 year period. Features and outcomes of this condition in the current series and the cases reported in the literature from 1986-1998 were reviewed.

DESIGN

Retrospective noncomparative case series.

PARTICIPANTS

All patients with this condition seen at the three participating general hospitals were included.

INTERVENTION

A review of the systemic and ocular characteristics, therapeutic methods, and final outcomes in patients afflicted with this condition.

MAIN OUTCOME MEASURES

Features studied included patients' demographic characteristics, microbiology, source of infection, ocular features, therapeutic interventions, final visual and anatomic outcomes.

RESULTS

Nineteen (70%) of the 27 incriminating organisms in this case series were gram negative microbes, with Klebsiella pneumoniae infections alone being responsible in 16 (60%) cases. Hepatobiliary tract infection was the source of bacteremia in 13 (48%) patients. Only nine (28%) eyes obtained good final visual acuity (20/120 or better), and two eyes were enucleated/eviscerated. A literature review of 209 patients with endogenous endophthalmitis over a 12 year period showed a similar increase in the frequency of gram negative microbes as the responsible organism, especially among the East Asian population. Overall, 22% had bilateral involvement; two thirds of patients had predisposing factor(s) or underlying illness(es), and diabetes mellitus was present in 46%. Thirty-four percent of all eyes obtained counting finger or better final vision, and 16% had their eyes eviscerated or enucleated. Infections with virulent organisms (gram negative rods, Serratia, Bacillus) usually denoted a grave visual prognosis; however, a media that was not opaque on presentation was usually associated with a good prognosis.

CONCLUSION

Metastatic ocular infection is not uncommon despite the availability of modern antibiotic therapy. Among the East Asian population, the patient at highest risk is a diabetic patient with Klebsiella pneumoniae hepatobiliary infection. In contrast, in the Caucasian population, this condition occurs in predisposed patients with gram-positive bacteremia arising from endocarditis or skin/joint infections. The final visual outcome in patients with endogenous bacterial endophthalmitis in the recent 12 years has not differed significantly from five decades ago.

Rapid identification of Pseudomonas aeruginosa from ocular isolates by PCR using exotoxin A-specific primers

The purpose of this research was to evaluate the use of PCR for the identification of ocular isolates of Pseudomonas aeruginosa by using primers specific to the exotoxin A gene of the bacteria. Genomic DNA was obtained from ocular microbial isolates of keratitis patients. Primers were designed based on the published sequence of the exotoxin A gene of P. aeruginosa. Using the primers designed, PCR reactions were performed on the DNA samples. The PCR was also examined for its specificity and sensitivity. In addition, a direct PCR using heating method was attempted on P. aeruginosa with no separate DNA extraction step. ATCC strains of P. aeruginosa were included as positive controls. The rest of the bacteria other than P. aeruginosa served as negative controls. A single band was obtained when analysed on agarose gel electrophoresis only from samples that contained genomic DNA of P. aeruginosa. The direct PCR method was also successful with the same band produced from the amplification. The whole process was completed within 4 h. The direct PCR amplification targeting at the exotoxin A gene of P. aeruginosa is potentially a rapid, specific, sensitive and relatively simple method for the identification of ocular isolates of P. aeruginosa.

Eye cancer incidence in Singapore

AIM

To describe the epidemiological characteristics of patients with primary intraocular, conjunctival, and orbital cancers seen in Singapore from 1968 to 1995.

METHODS

Epidemiological data of all cancers diagnosed in Singapore are collected by the Singapore Cancer Registry. The data of all cases of Singapore residents with eye cancers (ICD-9, site 190) were retrieved for analysis. This includes intraocular, conjunctival, and orbital cancers but excludes cancer of the eyelids.

RESULTS

There were 125 patients of which 67 (53.6%) were male and 58 (46.4%) were female. The average annual age standardised incidences for male and female Singapore residents were 1.89 and 1.81 per million respectively. The most common cancer was retinoblastoma (53.6%), followed by malignant melanoma (19.2%) and squamous cell carcinoma (11.2%). The most common cancer among patients younger than 15 years was retinoblastoma (95.7%) and that for those 15 years and older was malignant melanoma (42.6%). The most common subsite was the retina (53.6%), followed by conjunctiva (12.8%), orbit (8.8%), and lacrimal gland (6.4%).

CONCLUSION

The annual age standardised incidence have been stable for the 28 years studied. Retinoblastoma is much more common than melanoma in Singapore. These expanded epidemiological characteristics serve to provide ophthalmologists and epidemiologists with a foundation to monitor future disease patterns in Singapore and provide a basis for comparison with other selected populations elsewhere.

Treatment of de novo acute myeloid leukaemia in Hong Kong: a twenty-year experience (1975 to 1996)

BACKGROUND

Small patient numbers and short follow-up are common in some acute myeloid leukaemia (AML) studies and data on secondary malignancies after treatment of AML are rare.

AIMS

To determine the prognostic factors and long-term treatment results.

METHODS

A retrospective study of patients with de novo AML under the age of 60 over a 20-year period in which two induction therapy regimens: 7:3 (1975-1983) and 7:3:7 (1984-1996) and three consolidation chemotherapy regimens: 5:2 (1975-1983), 5:2:5 (1984-1990) and Ara-C/mitoxantrone (1991-1996) were used. Disease-free (DFS), overall survivals (OS) and prognostic factors were analysed.

RESULTS

Two-hundred and two of 276 (73%) patients attained complete remission (CR). The CR rates of 7:3 and 7:3:7 regimens were 70.5% and 74.5% respectively (p=0.92). The median DFS was 12 months and the projected DFS at 10- and 20-years were 23% and 21% respectively. For patients consolidated with 5:2, 5:2:5 and Ara-C/mitoxantrone, the median DFS was 15 m, 12 m and 11 m respectively and the projected ten-year DFS were 27%, 21% and 18% respectively (p=0.2). Ninety per cent of relapses occurred within two years from remission but there were two late relapses at 109 m and 120 m respectively. Young age and FAB M3 subtype were favourable prognostic factors to OS (p=0.04) and DFS (p=0.006) respectively. There was no secondary solid tumour in the long-term survivors.

CONCLUSION

Our experience confirmed the efficacy of standard-dose Ara-C/daunorubicin and the prognostic value of age and FAB subtype. Median and projected DFS were similar to western studies.

The results of adjustable suture technique in paediatric strabismus surgery

PURPOSE

Adjustable suture technique (AST) has been shown to be an effective treatment method in adult strabismus. The application of AST is not well studied in children due to potential poor cooperation during adjustment and the concern that the adjustment process can not be completed. The present series evaluates the efficacy and safety of this technique in a preselected group of children between 7 and 15 years of age.

METHODS

A retrospective review of 89 consecutive children undergoing AST was completed to assess: (1) the ability to perform and complete adjustment in children; (2) the frequency of need to perform adjustment; and (3) accuracy of surgical alignment. Only patients with horizontal rectus muscle surgery were included.

RESULTS

All children successfully completed the AST on the first post-operative day. Of the 89 patients, 24 (27%) required further adjustment by the AST. The mean follow-up period was 13.1 months. Fifty-three patients (60%) had previous strabismus surgery (range 1 to 5 operations). Sixty-six (74%) patients achieved successful alignment. Complications included slipped muscles in 1 case and difficulty in recession of the lateral rectus muscle in 1 patient.

CONCLUSIONS

Twenty-seven per cent of the patients required post-operative adjustment. The AST achieved an overall 74% successful alignment. Application of the AST should be considered in children with horizontal deviations over age 7 years, especially in the reoperations of esotropia.

Clinical features of congenital absence of the superior oblique muscle as demonstrated by orbital imaging

INTRODUCTION

Absence of an extraocular muscle was considered rare when demonstrable only by surgical exploration or necropsy. This study presents advances in orbital imaging to correlate clinical findings with absence of the superior oblique (SO) muscle.

METHODS

We performed high-resolution coronal orbital imaging by magnetic resonance imaging (222 orbits) or computerized radiographic tomography (32 orbits) in 127 patients with strabismus. We reviewed the histories and ocular motility examinations in patients who had absence of 1 or both SO muscles. Findings were compared with patients who were clinically diagnosed with SO palsy but had demonstrable SO muscles on orbital imaging.

RESULTS

SO muscles were absent in 6 patients. All had histories suggesting congenital strabismus. In patients old enough for quantitative testing who had unilateral SO muscle absence, visual acuity was a least 20/25 in all and stereopsis was better than 80 arc/s in one. Three patients were orthotropic in primary position. Five patients with unilateral SO muscle absence had clinical findings variably consistent with SO palsy, whereas a sixth patient with Duane syndrome had clinically unsuspected bilateral SO muscle absence. Versions and patterns of hypertropia in patients with SO muscle absence overlapped findings of 20 patients with SO palsy but demonstrable SO muscles.

CONCLUSIONS

Imaging can frequently demonstrate absence of the SO muscle in patients with SO palsy. Such patients may have good vision and stereopsis and clinical findings indistinguishable from SO palsy without absence of the SO muscle. Orbital imaging should be considered in the evaluation of congenital SO palsy to facilitate planning of effective surgical correction.

Incidence of eyelid cancers in Singapore from 1968 to 1995

AIM

To describe the epidemiological characteristics of patients with eyelid malignancies seen in all hospitals in Singapore from 1968 to 1995.

METHOD

The Singapore Cancer Registry has been collecting epidemiological data of all cancers seen in Singapore since 1968. The data of all cases of Singapore residents with eyelid cancers diagnosed from 1968 to 1995 (ICD-9, sites 172.1 and 173.1) were retrieved for analysis.

RESULTS

There were 162 male patients (49.8%) and 163 females (50.2%). The median age at diagnosis was 63 years in males and 66 years in females. The average annual age standardised incidence rate among male Singapore residents was 6.5 per million and 5.5 per million among female Singapore residents. Between 1993 and 1995, the average annual rate for females was 6.8 per million, compared with 3.1 per million between 1968 and 1972. The most common cancer was basal cell carcinoma (84.0%), followed by sebaceous adenocarcinoma (10.2%) and squamous cell carcinoma (3.4%).

CONCLUSION

The annual age standardised incidence for male residents has remained relatively stable. The incidence for female residents has shown a steady increase over the past 28 years. The incidence for males is generally higher than that for females. These expanded epidemiological characteristics may serve to provide a foundation to monitor future disease patterns and to promote further research into the aetiology of these cancers.

A reverse dot-blot method for rapid detection of non-deletion alpha thalassaemia

A reverse dot blot method based on membrane-bound allele-specific oligonucleotides as hybridization targets for amplified alpha-gene fragments has been developed for the rapid detection of four non-deletion alpha thalassaemia defects found in the Chinese. Since these non-deletion defects account for 22 8% of haemoglobin H disease, a sensitive, specific and rapid screening method should be of value.

Allogeneic bone marrow transplantation for adult acute lymphoblastic leukemia: a single-centre experience

Between 1990 and 1997, we performed 29 allogeneic BMTs for acute lymphoblastic leukemia (ALL) patients with HLA-identical sibs. Their median age was 31 years (range 15 to 43); there were 15 males and 14 females. The conditioning protocol was Cy-TBI (n = 15), VP16-Cy-TBI(n = 12), CBV (n = 1) and Bu-Cy (n = 1). Cyclosporin and methotrexate were used for GVHD prophylaxis. The median disease-free survival (DFS) was 12 months (range 1 to 92) with an actuarial 4-years DFS of 42.3 per cent. Three patients died of transplant-related complications before 100 days. Relapse occurred in 11 cases at a median time of 5 months (range 3 to 14). All nine patients relapsing within one year died form resistant leukemia. Three patients died of late treatment-related complications. There were 13 survivors (median follow-up 38 months, range 12-98), with 12 in remission. Only four had limited cGVHD, and all had 100 per cent performance scores. One patient also cleared her chronic hepatitis B carrier status due to acquired immunity. The DFS rates amongst CR1 cases and R1/CR2 cases were comparable (p = 0.39). No long-term DFS is obtained from patients with resistant disease (n = 4). The survival results for BMT at CR1 were superior to those using intensive chemotherapy consolidation (p = 0.29), mainly due to poor late results in the chemotherapy arm. For young ALL patients with HLA-matched siblings, the option of BMT should be considered in light of local consolidation survival results.

Nosocomial Klebsiella pneumoniae conjunctivitis resulting in infectious keratitis and bilateral corneal perforation

PURPOSE

Klebsiella pneumoniae is a known cause of metastatic endophthalmitis. However, the organism has never been described to cause severe infectious keratoconjunctivitis. We report a fulminant case of nosocomial K. pneumoniae conjunctivitis complicated by infectious keratitis and corneal perforation in both eyes.

METHODS

An 83-year-old previously healthy Chinese woman, blind in the right eye from rubeotic glaucoma and with bilateral dense cataracts, was admitted for observation after a head injury. While in hospital, she developed purulent bilateral conjunctivitis. Repeated cultures grew K. pneumoniae. This rapidly progressed to severe infectious keratitis and corneal perforation in both eyes, despite intensive antibiotics to which the organism was susceptible. The patient was otherwise well, and investigations did not reveal any source of endogenous sepsis.

RESULTS

The patient lost complete vision in both eyes. The left eye turned phthisical, and the right eye was eviscerated for uncontrolled endophthalmitis.

CONCLUSION

Although not previously reported, K. pneumoniae can cause devastating keratoconjunctivitis resulting in corneal melt, perforation, and uncontrolled endophthalmitis.

Allogeneic bone marrow transplantation for severe aplastic anemia: the Hong Kong scenario

Severe aplastic anemia (SAA) is a disease associated with high mortality. For young patients with HLA identical siblings, allogeneic bone marrow transplantation (BMT) offers the best chance of cure. Favourable results have also been reported using immunosuppressive therapy (IST). Transplantation is usually favoured for patients below 45 years of age. We report our experience of 11 allogeneic and one syngeneic BMT for adult Chinese patients with SAA, over a 4-year period from 1991 to 1995. Ten of the 12 (83 per cent) patients had received and failed prior IST including anti-thymocyte globulin (ATG) before being referred for BMT. Neutrophil and platelet engraftment was successful in 11 of them (92 per cent) and nine were completely transfusion independent after transplantation. Their overall 3-year survival was 67 per cent. The compromised overall result was due to a number of cases transplanted after a long time delay. No patient transplanted beyond 3 years from the initial time of diagnosis of SAA achieved long-term marrow engraftment, and they all eventually succumbed. On univariate analysis, a longer time delay and hence a larger amount of blood products exposure, were highly significantly statistically associated with inferior marrow engraftment and patient survival. Other factors including age, iron status, infused cell dose and the conditioning protocol were not found to significantly affect engraftment and survival. Graft versus host disease was clinically mild or absent in most patients. This may be related to ethnicity or previous ATG exposure. In conclusion, early allogeneic BMT was a safe and effective treatment in our small series of patients with SAA failing IST.

Hemophilia B in a female carrier due to skewed inactivation of the normal X-chromosome

A novel missense mutation (codon 351, GCT (Ala) --> CCT (Pro)) of the FIX gene was characterised in a young female with mild hemophilia B. She is heterozygous for the FIX mutation inherited from her carrier mother. Analysis of the methyl-sensitive Hpa II sites at the 5' end of the hypoxanthine phosphoribosyltransferase gene showed that skewed inactivation of the X chromosome carrying her normal FIX gene accounted for the hemophilia phenotype.

Clinical significance of alimentary tract microbes in bone marrow transplant recipients

A prospective study on the microbes isolated from the alimentary tract in 120 bone marrow transplant (BMT) recipients (1991-1993) was undertaken to define the spectrum of organisms isolated under antimicrobial prophylaxis, their temporal sequence of emergence, and the associated morbidity and mortality. Clostridium difficile (n = 20), isolated in the pre-engraftment and early post-engraftment periods (day 2-45 post-BMT), was the most common microbe recovered from stool of patients with diarrhea. In contrast to previous reports, no significant difference in mortality was observed between patients with and without C. difficile isolated in stool. Two patients had neutropenic ileocecitis with concomitant bacteremia due to Escherichia coli and Klebsiella pneumoniae. One patient was found to have astrovirus gastroenteritis (day 7), and Giardia lamblia was recovered from the stool of another (day -7). Heavy growth of Staphylococcus aureus from direct smear-positive specimens was found from the upper airway of two patients with severe mucositis and complete dysphagia (day 12 and 23). Salmonella spp. of groups B and E were found in the stool of five asymptomatic patients at the time of conditioning. No specific organisms was recovered from the endoscopic brushing of two patients with lower end esophagitis, three patients with upper gastrointestinal bleeding, and three patients with perirectal cellulitis. During the post-engraftment period, five patients had documented cytomegalovirus gastroenterocolitis (days 34-97), one had Mycobacterium chelonae colitis (day 70), and another had nodular gastritis due to Acremonium falciforme (day 270). Overall, only 28% of patients with alimentary tract symptoms/syndrome had specific pathogens isolated from clinical specimens. Differentiation of the causation of alimentary tract symptoms was often difficult because noninfectious complications such as conditioning toxicity, graft-versus-host disease, and its treatment often caused alimentary tract symptoms in addition to predisposed BMT patient to infection. The reluctance of obtaining tissue biopsy for ascertaining the importance of those potential alimentary tract pathogens often dictate the use of empirical treatment.

Pentasomy 8q in myelodysplasia

Trisomy 8 and, less commonly tetrasomy 8, are karyotypic aberrations found in myeloid malignancies. We describe a unique case of acute myeloid leukemia with partial pentasomy 8 resulting from duplication of isochromosome 8q, and discuss its possible roles in leukemogenesis.

Treatment of adenovirus-associated haemorrhagic cystitis with ganciclovir

We report a 47-year-old bone marrow transplant recipient with haemorrhagic cystitis caused by adenovirus successfully treated with ganciclovir. This is the first report on the use of ganciclovir for the successful treatment of adenoviral infection. Shell vial culture may be more sensitive than conventional culture in the detection of adenovirus in such patients.

Human herpesvirus-6 and human herpesvirus-7 infections in bone marrow transplant recipients

Human cytomegalovirus (HCMV), human herpesvirus-6 (HHV-6), and human herpesvirus-7 (HHV-7) DNA in peripheral blood leukocytes (PBL) of 61 bone marrow transplant recipients was monitored weekly during the first 12 weeks post-transplantation by a nested polymerase chain reaction (PCR). Thirty-seven (61%), 17 (28%), and 32 (53%) of patients had one or more PBL specimens positive for HCMV, HHV-6 or HHV-7 DNA, respectively. HHV-7 DNA in PBL during the early post-transplant period was associated with a longer time to neutrophil engraftment (mean 28.8 days vs 19.8 days; P = 0.01). In two patients who failed to engraft, HHV-6 DNA and HHV-7 DNA was detected in plasma and PBL, respectively, early in their post-transplant period. Patients with HCMV disease were more likely to have concurrent HHV-7 DNA in PBL prior to onset of disease than were patients with asymptomatic HCMV infection, suggesting that HHV-7 may be a cofactor in the progression from HCMV infection to HCMV disease. In the 17 patients (179 specimens) in whom viral DNA in plasma was studied (in addition to PBL), a positive result was found only in 3. In each, viral DNA in plasma appeared to correlate with clinically significant disease. HHV-7 DNA in plasma was associated with encephalitis in an allograft recipient.