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1. The effects of venous occlusion on the coagulation and fibrinolytic systems were investigated in six patients with type 1 (insulin-dependent) diabetes and 11 age- and sex-matched non-diabetic control subjects. The coagulation parameters (fibrinogen, prothrombin time, partial thromboplastin time with kaolin, von Willebrand factor antigen) did not differ between patients and control subjects either before or after 20 min of venous occlusion. No rise was observed in von Willebrand factor antigen after venous occlusion in either group. 2. In the diabetic patients, chronic activation of the fibrinolytic system was found at baseline, which was indicated by a shortened euglobulin lysis time (P < 0.01), increased tissue plasminogen activator activity (P < 0.05) and decreased plasminogen activator inhibitor type 1 antigen level (P < 0.05), when compared with control subjects. In both groups venous occlusion resulted in significant increments in all measurements, except plasminogen activator inhibitor type 1 antigen level. The post-occlusion values did not differ between the two groups, except the plasminogen activator inhibitor type 1 antigen level, which remained significantly lower in the diabetic patients. The mean increments in each parameter did not differ between the two groups. 3. Coagulation and fibrinolysis were assessed in response to acute insulin-induced hypoglycaemia. Von Willebrand factor antigen levels increased significantly in both groups, with no difference in maximal increments. Significant activation of the fibrinolytic system occurred in response to hypoglycaemia, demonstrated by shortened euglobulin lysis time and increased fibrin plate lysis, tissue plasminogen activator antigen level and tissue plasminogen activator activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Objectives: To determine the prevalence of and risk factors for myocardial dysfunction in HIV infection., Subjects: 173 patients infected with HIV underwent echocardiography. 119 were current or previous injection drug users, 38 were homosexuals, 10 were haemophiliac patients, and six were heterosexual., Main Outcome Measure: Detection of impaired ventricular function., Results: 26 patients with abnormalities of ventricular size or function or both were identified. The abnormality was (a) dilated cardiomyopathy in 13 patients (eight homosexuals, three drug users, and two haemophiliacs) with a mean CD4 count of 38 cells/mm3, which accords with end-stage disease (in addition, three patients were identified as having borderline impairment of left ventricular function); (b) left ventricular dilatation without loss of function in a further six patients; and (c) isolated right ventricular dilation in seven patients. Follow up echocardiograms were obtained in 71 patients, 18 of whom had myocardial dysfunction (103 echocardiograms, mean (SD) 2.5 (0.6) scans per patient, mean interval 200 (116) days, range 14-538 days). These showed that in four cases of isolated right ventricular dilatation, one of isolated left ventricular dilatation, and two with borderline left ventricular dysfunction myocardial function subsequently reverted to normal. There was no excess of exposure to zidovudine in the patients with myocardial dysfunction. Similarly, patients with myocardial dysfunction had no serological evidence of excess secondary infection with Toxoplasma gondii and cytomegalovirus., Conclusions: There was a high prevalence and wide range of myocardial dysfunction in HIV positive patients. Dilated cardiomyopathy was a feature of advanced HIV disease and affected all major risk groups for HIV infection. In contrast, isolated dilatation of either ventricle occurred at an earlier stage of HIV infection and, particularly in the case of the right ventricle, often was transient. Neither treatment with zidovudine nor infection with Toxoplasma gondii or cytomegalovirus seemed to be responsible for these findings.

This study was designed to assess whether factors other than high haemoglobin, thrombocytosis and abnormal platelet function predispose to thrombosis in polycythaemia rubra vera (PRV). Components of the fibrinolytic system and concentrations of the naturally occurring anticoagulants were measured in patients and controls in the resting state; the fibrinolytic capacity was reassessed after venous occlusion. The results were related to presence or absence of a history of thromboembolism. Under resting conditions, patients with PRV had reduced plasminogen activator inhibitor antigen levels and higher fibrin plate lysis area and tissue plasminogen activator activity. Protein C, protein S and factor V levels were reduced. Those patients with a history of thromboembolism had decreased tissue plasminogen activator activity after venous occlusion compared to those who had not experienced a thrombosis. We conclude that reduced fibrinolytic capacity may predispose to thrombosis in PRV. Despite treatment to normalize haemoglobin levels, the patients have persistent activation of their fibrinolytic systems. This, and reduced levels of proteins C and S, may be secondary to a chronic, clinically occult, disseminated intravascular coagulation.

The effect of factor VIII concentrate, from commercial and National Health Services manufacturers, on in vitro lymphocyte proliferative response to allogeneic stimulator cells was investigated. Factor VIII preparations 'purified' by ion exchange or by monoclonal antibody affinity had no effect in this assay but lymphocyte proliferation in response to allogeneic cells was markedly and consistently enhanced by some intermediate purity factor VIII concentrates and, to a lesser extent, by a factor IX preparation. These preparations did not stimulate lymphocyte proliferation in the absence of other mitogens. The co-mitogenic factor(s) present in intermediate purity factor VIII was not identified. However, enhanced proliferation was not due to factor VIII itself, nor to albumin or fibronectin. The clinical relevance of the immunomodulatory activity of intermediate purity factor VIII concentrates in vitro is discussed.

In an investigation of the evolution of the third hypervariable loop of gp120 (V3), the principal neutralization determinant of human immunodeficiency virus type 1, we have analyzed 89 V3 sequences of plasma viral RNA purified from peripheral blood samples donated over 7 years by an infected hemophiliac. Considerable sequence diversity in the V3 region was found at all time points after seroconversion. Phylogenetic analysis revealed that an important diversification had occurred by 3 years postinfection and that, subsequently, most sequences could be allocated to either one of two major lineages that persisted throughout the remainder of the infection. Rapid changes in frequency of the most common sequences and the observation that the same hexapeptide motif (GPGSAV) at the crown of the V3 loop has evolved convergently provide strong evidence that selective processes determine the evolutionary fate of sequence variants in this region.

A 26-year-old HIV positive severe haemophiliac developed Burkitt-type acute lymphoblastic leukaemia with intracranial involvement. He underwent standard combination therapy, and entered complete remission. Syngeneic bone marrow transplantation (BMT) was undertaken; the donor was also HIV positive. The patient died 18 months from transplant of isolated intracranial relapse, with no evidence of systemic relapse. Unlike other types of non-Hodgkin's lymphoma, Burkitt's type occurs in HIV positive patients with relatively normal CD4 cell counts. Remission can be achieved using intensive chemotherapy, and since these patients may otherwise have a reasonable life expectancy, BMT may be appropriate.

To investigate the prevalence of hepatitis C virus infection in two risk groups, stored serum samples from treated haemophiliacs and intravenous drug users were tested for anti-HCV by both anti-C-100 based and second generation ELISAs (Abbott and Ortho) followed by testing in two confirmatory immunoblot assays that incorporate core as well as other non-structural antigens (Innogenetics LIA and Chiron RIBA-HCV test). Clear evidence of HCV infection was found in all but one of 78 haemophiliacs treated with non-virus inactivated clotting factor concentrates, but in none exposed only to super dry heat-treated concentrates. Only four samples gave rise to conflicting serological results between the four tests, two of these occurred in patients with advanced HIV related disease and almost certainly reflected loss of humoral immunity associated with disease progression, and the others occurred in the only two patients tested who were chronic carriers of hepatitis B infection and may reflect an interaction between the two viruses. Comparison of anti-C-100 versus second generation tests in immunocompetent drug users revealed a false negative rate of 20% using C-100 alone, indicating the advantage of using second generation assays for detection of past or current HCV infection. Of all of the antigens used in the confirmatory assay, positive sera showed strongest and most frequent reactivity with the C22 and C33c proteins (Ortho RIBA).

10 years ago, it became apparent that haemophiliacs were developing diseases which were indicative of underlying immunodeficiency. The results of investigation confirmed that many had abnormal immune systems, particularly with regard to cell-mediated immunity. These abnormalities were thought to be a consequence of the use of clotting factor concentrates, and indeed the discovery of HIV and its mode of transmission, confirmed these suspicions. However, it subsequently became clear that HIV infection did not explain all the abnormalities observed. Many in vivo studies have shown that the immune systems of HIV-negative haemophiliacs are not entirely normal, and in vitro studies have shown that clotting factor concentrates per se have a modulating effect on immune function. We have reviewed particularly the abnormalities seen in HIV-negative haemophiliacs and their possible causes, as well as the specific features of HIV infection in haemophiliacs.

Immunological studies were performed on a group of 44 haemophilia A and 15 haemophilia B patients who were treated exclusively with blood products manufactured by the Scottish National Blood Transfusion Service (SNBTS). All patients were HIV seronegative throughout the study. Of the haemophilia A patients 14 (32%) had CD4+ lymphocyte subset counts less than or equal to 0.5 x 10(9)/l, compared with one (6%) haemophilia B patient and four (8%) controls. The percentage of activated T cells was greater than 5% in 19/33 (57%) with haemophilia A, 5/9 (55%) haemophilia B and 14/50 (28%) of control subjects. beta 2 microglobulin values greater than or equal to 2.0 mg/l were observed in 19 (43%) haemophilia A and four (26%) haemophilia B patients, compared with one (2%) control. No significant increases in serum interleukin-2 receptor concentrations were observed in 15 haemophilia A and one haemophilia B patients. Significantly elevated levels of IgG, IgM and IgA were observed in the haemophilia A group, but elevation of immunoglobulins was restricted to the IgG class in the haemophilia B group. Of the haemophilia A patients 16/30 (53%) and 6/11 (54%) haemophilia B patients had depression of cell-mediated immunity (CMI) as assessed by delayed-type hypersensitivity responses to intradermally injected recall antigens. There was no correlation between factor VIII or factor IX usage and changes in lymphocyte subsets, beta 2 microglobulin, and immunoglobulin levels. There was, however, a strong correlation between annual factor VIII usage and the degree of depression of CMI for those with haemophilia A but not for those with haemophilia B. No correlation between alterations in the immune parameters and disturbance of liver function tests was observed in either haemophilia A or haemophilia B patients. We conclude that alloantigen or non-HIV viral exposure due to repeated administration of factor concentrates brings about alterations in the immune response, and that these changes are more marked following exposure to intermediate purity factor VIII compared with factor IX concentrate.

Markers of immune function present before infection may determine the subsequent course of disease in HIV-infected individuals. In 1983, we measured immune function in a group of haemophiliacs in Edinburgh. In 1984, 18 of these patients became infected with HIV-1 from contaminated factor VIII. We have followed-up these patients since their seroconversion. The rate of disease progression, as assessed by the appearance or not of AIDS symptoms or signs within five years of seroconversion, was related both to the concentration of total plasma IgM before exposure to infection and to the pattern of specific IgM and IgA anti-HIV response around the time of IgG seroconversion. Disease progression also correlated with concentrations of plasma interleukin-2 receptor (a marker of lymphocyte activation) and with the number and percentage of circulating DR + ve (activated) T cells. Our findings show that the extent of host immune reactivity, which may be genetically determined, is a powerful factor in the pathogenesis of HIV-associated disease.

Data have been collected by questionnaire on 15 acute bleeding episodes in 12 patients with acquired hemophilia, treated with porcine factor VIII (FVIII). The median initial anti-human FVIII inhibitor level was 40 Bethesda Units (BU)/ml, whereas that against porcine was 1 BU/ml. The mean initial dose of porcine FVIII infused was 54 micrograms/kg, which resulted in a rise of 0.57 IU/mL in the FVIII concentration. Therapy was continued for a mean of 8.5 days, during which time the average number of infusions was 11. Clinical response was rated as good or excellent in 82% of recipients. Side effects were uncommon; only one patient experienced a severe reaction. Following therapy, no increase in antihuman antibody levels was noted; increased levels of antiporcine antibody was detected in only two patients. One patient bled on three further occasions and was successfully retreated with porcine FVIII. Porcine FVIII is a safe and clinically effective treatment for bleeding episodes in acquired hemophilia and should be considered as first-line therapy for patients with low antiporcine FVIII levels.

Sequence change in different hypervariable regions of the external membrane glycoprotein (gp120) of human immunodeficiency virus type 1 (HIV-1) was studied. Viral RNA associated with cell-free virus particles circulating in plasma and proviral DNA present in HIV-infected peripheral blood mononuclear cells (PBMCs) were extracted from blood samples of two currently asymptomatic hemophiliac patients over a 5-year period. HIV sequences were amplified by polymerase chain reaction to allow analysis in the V3, V4, and V5 hypervariable regions of gp120. Rapid sequence change, consisting of regular replacements by a succession of distinct viral populations, was found in both plasma virus and PBMC provirus populations. Significant differences between the frequencies of sequence variants in DNA and RNA populations within the same sample were observed, indicating that at any one time point, the predominant plasma virus variants were antigenically distinct from viruses encoded by HIV DNA sequences in PBMCs. How these findings contribute to current models of HIV pathogenesis is discussed.

A highly sensitive and reliable RNA polymerase chain reaction method has been developed which has been used to detect, quantify and sequence cell-free HIV RNA directly from the plasma of seropositive individuals. Plasma from 10 out of 12 haemophiliacs tested was found to contain detectable levels of HIV-1 RNA [log mean value: 1.2 x 10(3) copies for Centers for Disease Control (CDC) group II patients, 5.5 x 10(3) copies for CDC group IV patients]. The presence of cell-free circulating virus in both symptomatic and asymptomatic individuals suggests that viral replication continues throughout the course of infection. The same procedure has been used to detect and sequence HIV-1 RNA in two batches of unheated commercial factor VIII concentrate distributed in 1981 and 1983. The sequences obtained revealed a closer relationship to North American than to African strains of HIV-1.

We describe three cases of consumptive coagulopathy caused by extensive thrombus formation in otherwise 'uncomplicated' aortic aneurysms. These cases demonstrate the importance of performing a coagulation screen in any patient presenting with thrombocytopenia who may have an aortic aneurysm. Effective therapy with low-dose heparin was demonstrated with subsequent haemostasis being maintained with warfarin.

We present an unusual case of light chain myeloma complicated by systemic amyloidosis. There was massive infiltration of the left iliopsoas and quadratus femoris muscles with amyloid, manifesting itself clinically as a progressive, painless limp. We point out that accurate diagnosis by muscle biopsy in such cases has important prognostic implications and may avoid the unnecessary use of potentially toxic and ineffective treatment.

The polymerase chain reaction (PCR) detected specific hepatitis C viral (HCV) RNA sequences in plasma from 15 of 21 haemophiliacs (12 HCV-antibody positive) and 7 of 27 intravenous drug users (13 HCV-antibody positive). Quantification of RNA-positive samples showed high levels of HCV (10(5) to 10(6) copies of RNA/ml) in infected patients. HCV was more frequently found in haemophiliacs infected with human immunodeficiency virus (11/11 HIV-positive and 4/10 HIV-negative patients). HCV-RNA was detected in all batches of commercially available factor VIII tested and in low concentrations in some pools of plasma donations from volunteers. Factor VIII, manufactured from volunteer donations, was uniformly negative by PCR. Phylogenetic analysis of viral sequences showed two distinct groups: one was associated with intravenous drug users and the other with haemophiliacs infected with Scottish factor VIII preparations. Both were distinct from sequences found in commercially available factor VIII.

Direct sequencing of segments of the envelope gene of human immunodeficiency virus type 1 proviruses in peripheral blood mononuclear cells has revealed that a cohort of hemophiliacs who were infected after exposure to a single common batch of factor VIII share closely related virus strains. Seventy-four sequences extending from hypervariable regions V4 through V5 from nine patients yielded a mean intrapatient nucleotide distance of 5.5%, while a mean of 4.2% was observed in 39 sequences of the V3 loop (six patients). Phylogenetic analysis revealed that sequences of six Edinburgh patients were particularly closely related and those from a patient infected in the United States were very distinct. The mean nucleotide distance among these six was 8.3%, while the mean distance from the U.S.-derived sequences was 25.5% in the V4-V5 region. The rate of sequence change across this patient group has been estimated to be 0.4% per year in the V4-V5 region and 0.5% per year in the V3 region, with at least a twofold range across patients. Only two inactivating nucleotide substitutions have been observed in a total of 42 kb of sequence obtained from the env and gag genes during this study.

Nucleotide sequences in three hypervariable regions of the human immunodeficiency virus type 1 (HIV-1) env gene were obtained by sequencing provirus present in peripheral blood mononuclear cells of HIV-infected individuals. Single molecules of target sequences were isolated by limiting dilution and amplified in two stages by the polymerase chain reaction, using nested primers. The product was directly sequenced to avoid errors introduced by Taq polymerase during the amplification process. There was extensive variation between sequences from the same individual as well as between sequences from different individuals. Interpatient variability was markedly less in individuals infected from a common source. A high proportion of amino acid substitutions in the hypervariable regions altered the number and positions of potential N-linked glycosylation sites. Sequences in two hypervariable regions frequently contained short (3- to 15-bp) duplications or deletions, and by amplifying peripheral blood mononuclear cell DNA containing 10(2) or 10(3) proviral molecules and analyzing the product by high-resolution electrophoresis, the total number and abundance of distinct length variants within an individual could be estimated, providing a more comprehensive analysis of the variants present than would be obtained by sequencing alone. Sequences from many individuals showed frequent amino acid substitutions at certain key positions for neutralizing-antibody and cytotoxic T-cell recognition in the immunodominant loop. The rates of synonymous and nonsynonymous nucleotide substitution in the region of this and flanking regions indicate that strong positive selection for amino acid change is operating in the generation of antigenic diversity.

Objective: To identify measures of immune state that reflect the course of HIV related disease in order to predict deterioration of symptoms and assess response to treatment., Design: Five year longitudinal clinical and laboratory study., Setting: Regional haemophilia centre, university virology laboratory, and Medical Research Council laboratory., Patients: 32 Patients with haemophilia A exposed to a single batch of HIV contaminated factor VIII concentrate from the Scottish National Blood Transfusion Service in 1984 who were followed up regularly in Edinburgh (31) or abroad (one)., Main Outcome Measures: Counts of circulating T cell subsets (CD4 and CD8); plasma beta 2 microglobulin, neopterin, and IgA concentrations; and delayed type hypersensitivity to multiple skin test antigens., Results: 18 Patients who seroconverted after exposure had received significantly more contaminated factor VIII than the 14 who did not (mean 43 (range 9-109) v 15 (3-30) phials, p less than 0.01). The two groups were not distinguishable by other criteria before exposure. The group that seroconverted subsequently showed a progressive fall in mean circulating CD4 lymphocytes and an increase in plasma beta 2 microglobulin and neopterin concentrations. From 1987 patients in this group also showed an increase in mean circulating CD8 lymphocytes and in plasma IgA concentration, neither of which was seen in patients who did not seroconvert. Patients with HIV antibody who developed Centers for Disease Control category IV symptoms within five years after infection showed more extreme changes in all measures, except CD8 lymphocyte count, than those whose symptoms remained in categories II and III. Skin test reactivity declined to barely detectable levels in all patients positive for HIV antibody., Conclusions: Serial estimates of circulating CD4 lymphocytes and of plasma beta 2 microglobulin concentration are the most reliable measures of disease progression; of these, beta 2 microglobulin concentration seems to be the better predictor of impending serious symptoms. High IgA concentrations reflect rather than predict disease state. Individual variation in most measures is such that a wide range of measurements should be used in assessing the effects of trial treatment in HIV infected patients without symptoms.

In human immunodeficiency virus (HIV)-infected individuals, the proportion of circulating mononuclear cells (PBMCs) which carry HIV provirus and the number of HIV proviral sequences per infected PBMC have been matters for conjecture. Using a double polymerase chain reaction which allows the detection of single molecules of provirus and a method of quantifying the provirus molecules, we have measured provirus frequencies in infected individuals down to a level of one molecule per 10(6) PBMCs. As a general rule, only a small proportion of PBMCs contain provirus (median value of samples from 12 patients, one per 8,000 cells), and most if not all of the infected cells carry a single provirus molecule. The frequency of provirus-carrying cells correlated positively both with the progression of the disease and with the success with which virus could be isolated from the same patients by cocultivation methods. Of seven asymptomatic (Centers for Disease Control stage II) patients, all but one contained one provirus molecule per 6,000 to 80,000 cells; of five Centers for Disease Control stage IV patients, all but one contained one provirus molecule per 700 to 3,300 cells. When considered in conjunction with estimates of the frequency of PBMCs that express viral RNA, our results suggest that either (i) the majority of provirus-containing cells are monocytes or (ii) most provirus-containing lymphocytes are transcriptionally inactive. We also present nucleotide sequence data derived directly from provirus present in vivo which we show is not marred by the in vitro selection of potential virus variants or by errors introduced by Taq polymerase. We argue from these data that, of the provirus present in infected individuals, the proportion which is defective is not high in the regions sequenced.

In a group of six normal male volunteers, infusion of DDAVP, venous occlusion and exercise were shown to increase plasma levels of factor VIII and plasminogen activator, activity and antigen, to different extents and at differing rates. Any mechanisms suggested to explain release of these proteins by various stimuli should account for such differences. All three stimuli could also increase plasma levels of prostacyclin metabolites, although this was only significant for high doses of DDAVP. Other potential endothelial markers, such as fibronectin and thrombospondin, showed no specific increase after any of the stimuli.

Eight patients on warfarin with rheumatic heart disease and prosthetic cardiac valves were selected for study on the basis of persistently elevated plasma beta-thromboglobulin (beta-tg) and platelet factor 4 (PF4) concentrations. Platelet mean lifespan and fibrinogen half life were short, and positively correlated, and both were inversely related to the plasma concentration of the platelet specific proteins. Antithrombin III (ATIII) levels were also reduced. Treatment with sulphinpyrazone resulted in lengthening of both platelet and fibrinogen survival, a rise in ATIII but no change in the beta tg or PF4 concentrations. It is concluded that patients with abnormal cardiac valves and raised plasma levels of beta tg or PF4 have, despite warfarin, a consumption coagulopathy that can be inhibited by sulphinpyrazone.

23 obligate carriers of mild and severe haemophilia A and 26 normal females were bled on three occasions, and their plasmas assayed for procoagulant factor VIII (VIIIC), factor VIII related antigen (VIIIRAg) and factor VIII clotting antigen (VIIICAg). A comparison of the ratios VIIIC/VIIIRAg and VIIICAg/VIIIRAg indicated that, although the two ratios gave the same proportional misclassification of carriers as normals (four of 23), the latter ratio showed greater discriminatory power when an unequal variances predictive method was used to calculate likelihood ratios (for carrier status). This greater power was shown to be due to a greater reproducibility between visits for the VIIICAg/VIIIRAg ratio. Discrimination was considerably better when the median of the three median values for each variable was analysed, compared to the median value obtained at the first visit. There was also no statistical difference between VIIICAg/VIIIRAg (or VIIIC/VIIIRAg) ratios obtained from carriers of severe compared to mild haemophilia.

Sequential serum samples from 18 haemophiliac patients exposed simultaneously to human immunodeficiency virus type 1 (HIV 1) in early 1984 were tested retrospectively for serological markers of infection. Assay for total antibodies to HIV established that the time to seroconversion might be as long as 110 days after exposure to contaminated factor VIII; serum samples were also tested by Western blotting, by enzyme linked immunosorbent assay (ELISA) for specific antibodies to envelope and core proteins, and for p24 antigen by two assay systems during the two years after infection. The studies showed that five of the 12 patients for whom serum samples obtained between exposure and seroconversion were available had transient p24 antigenaemia. Although amounts of total antibody to HIV and of antibodies to envelope proteins rose continuously during the two years of the study, amounts of antibody to the core protein were variable and tended to decline in patients who became symptomatic. Two patients had persistent p24 antigenaemia that began four months after seroconversion; these patients remained asymptomatic. One patient who developed the acquired immune deficiency syndrome (AIDS) had transient antigenaemia at the time of seroconversion but failed to show any antigen for the rest of the study; progression to AIDS was accompanied by an increase in antibodies to envelope proteins. Much of the variability in the course of infection with HIV must represent the differences in the susceptibility of the patients to infection.

Two batches of heat-treated factor VIII concentrate were found to contain anti-HIV-positive plasma donations. The batches were dry-heat-treated at 68 degrees C for 2 and 24 h, respectively. No HIV seroconversions occurred in 13 susceptible haemophiliacs receiving a total of 540 bottles of these factor VIII preparations.

The measurement of platelet lifespan and the plasma concentration of beta-thromboglobulin and platelet factor 4 are potentially useful techniques for assessing platelet function in vivo. Recent clinical and laboratory studies are reviewed.

During each of the four-year periods 1971-1975 and 1975-1979, the annual incidence of hepatitis B infection has been assessed in 56 patients with haemophilia A by measuring plasma HBsAg, anti-HBs and anti-HBc levels. Infection rates of 7% and 9.5% per annum respectively were observed for each four-year period despite the screening of individual blood donations for HBsAg by techniques up to the sensitivity of reversed passive haemagglutination. The highest incidence of seroconversion was amongst severe haemophiliacs many of whom had received treatment predominantly with cryoprecipitate. Of the 16 patients in whom serological evidence of hepatitis B infection was obtained only one had an accompanying clinical episode of hepatitis. We conclude that haemophiliacs are still at high risk of infection by hepatitis B virus despite the screening of individual blood donors for HBsAg.

The present study was designed to investigate the survival of platelets of differing densities in normal and post-splenectomized subjects. Autologous platelets, labelled with 111In-oxine, were reinjected into normal subjects (n = 12); 63% were recovered in the circulation and their survival curve was linear with a T 1/2 of 4.5 d. When the platelets were layered onto a continuous Percoll gradient, they formed a band extending between 1.040 and 1.080 g ml-1. After fractionation of the gradient the specific radioactivity of 111In platelets recovered was measured. The specific activity of low density platelets (average 1.050 g ml-1) decreased rapidly with a T 1/2 of 2.0 d, whilst medium density platelets (average 1.060 g ml-1) survived with a T 1/2 of 4.5 d; high density platelets (average 1.073 g ml-1) exhibited a T 1/2 greater than 5.0 d. This latter population of high density platelets also showed a significant increase in specific activity on the first day following injection. In post-splenectomy subjects a similar relationship between density and 111In associated activity was observed but no increase in the specific activity of the dense platelets on day 1 was observed. We conclude that high density autologous 111In-platelets are preferentially retained in the spleen and have a more prolonged survival than those of lower density.

Psychiatric morbidity, relevant symptoms and satisfaction with communication were assessed in patients suffering from malignant lymphoma. Before treatment started 15 of 40 patients had clinically significant psychiatric morbidity. Treatment, in its early stages, was not associated with a significant change in mean psychiatric morbidity scores but there was a decrease in ratings of concern about illness and an increase in ratings of nausea. Eleven of 31 patients seen for a second interview reported dissatisfaction with some aspect of communication with the medical staff. The findings suggest that emotional distress can be contained with a policy of frank communication; nevertheless dissatisfaction is common, being associated with initial less concern, good general health and neurotic personality traits. Personality assessment should be incorporated in future studies of doctor-patient communication.

During the collection of samples for plasma beta-thromboglobulin (beta-TG) determination, it is well established that artificially high values can be observed due to in-vitro release. To estimate the reliability of a single beta-TG measurement, blood samples were collected simultaneously from both arms on two separate occasions in 56 diabetic patients selected for a clinical trial. From each arm, blood was taken into two tubes containing an anticoagulant mixture with (tube A) and without (tube B) PGE1. The overall mean value of B-TG in tube B was 1.14 times higher than in tube A (p less than 0.01). The markedly large between-arms variation accounted for the most part of within-subject variation in both tubes and was significantly greater in tube B than in tube A. Based on the difference between B-TG values from both arms, the number of subjects with artificially high B-TG values was significantly higher in tube B than in tube A on each occasion (overall rate: 28% and 14% respectively). Estimate of between-occasions variation showed that B-TG levels were relatively stable for each subject between two occasions in each tube. It is concluded that the use of PGE1 decreases falsely high B-TG levels, but a single measurement of B-TG does not provide a reliable estimate of the true B-TG value in vivo.

An immunoradiometric assay (IRMA) has been developed based on the inhibitor which arose in a polytransfused severe haemophiliac. The two-site IRMA measures antigens closely associated with the procoagulant parts of the factor VIII complex, which are termed FVIIC antigens or FVIIICAG. FVIIICAG was present in normal plasma and also, at a slightly lower concentration, in normal serum. In 37 patients with haemophilia A, 36 had FVIIICAG levels of less than 10% of the normal plasma pool. In patients with von Willebrand's disease the levels of FVIIIC and FVIIICAG were in good agreement, both before and after treatment with cryoprecipitate or DDAVP. FVIIICAG was relatively stable in plasma at 37 degrees C and could also be detected in cord and fetal serum. The assay is of potential value for detecting reduced levels of factor VIII, for carrier detection and for the prenatal diagnosis of haemophilia.