Molecular cloning and disease association of hepatitis G virus: a transfusion-transmissible agent

An RNA virus, designated hepatitis G virus (HGV), was identified from the plasma of a patient with chronic hepatitis. Extension from an immunoreactive complementary DNA clone yielded the entire genome (9392 nucleotides) encoding a polyprotein of 2873 amino acids. The virus is closely related to GB virus C (GBV-C) and distantly related to hepatitis C virus, GBV-A, and GBV-B. HGV was associated with acute and chronic hepatitis. Persistent viremia was detected for up to 9 years in patients with hepatitis. The virus is transfusion-transmissible. It has a global distribution and is present within the volunteer blood donor population in the United States.

Selective alterations in gene expression for NMDA receptor subunits in prefrontal cortex of schizophrenics

NMDA receptor antagonists can induce a schizophrenia-like psychosis, but the role of NMDA receptors in the pathophysiology of schizophrenia remains unclear. Expression patterns of mRNAs for five NMDA receptor subunits (NR1/NR2A-D) were determined by in situ hybridization in prefrontal, parieto-temporal, and cerebellar cortex of brains from schizophrenics and from neuroleptic-treated and nonmedicated controls. In the cerebral cortex of both schizophrenics and controls, mRNAs for NR1, NR2A, NR2B, and NR2D subunits were preferentially expressed in layers II/III, Va, and VIa, with much higher levels in the prefrontal than in the parieto-temporal cortex. Levels of mRNA for the NR2C subunit were very low overall. By contrast, the cerebellar cortex of both schizophrenics and controls contained very high levels of NR2C subunit mRNA, whereas levels for the other subunit mRNAs were very low, except NR1, for which levels were moderate. Significant alterations in the schizophrenic cohort were confined to the prefrontal cortex. Here there was a shift in the relative proportions of mRNAs for the NR2 subunit family, with a 53% relative increase in expression of the NR2D subunit mRNA. No comparable changes were found in neuroleptic-treated or untreated controls. These findings indicate regional heterogeneity of NMDA receptor subunit expression in human cerebral and cerebellar cortex. In schizophrenics, the alterations in expression of NR2 subunit mRNA in prefrontal cortex are potential indicators of deficits in NMDA receptor-mediated neurotransmission accompanying functional hypoactivity of the frontal lobes.

A polymorphism in randomly amplified DNA that differentiates the Y chromosomes of Bos indicus and Bos taurus

A small number of west African Bos taurus cattle breeds, including the N'Dama, constitute a valuable genetic resource by virtue of their ability to remain productive under trypanosomiasis challenge. However, introgression of Bos indicus genes into the trypanotolerant breeds, particularly by introduction of zebu bulls, is a threat to this resource. This work describes the characterization and cloning of a bovine randomly amplified polymorphic DNA (RAPD) that is generated in polymorphic DNA (RAPD) that is generated in polymerase chain reaction (PCR) with the 10 base primer ILO1065 from Bos indicus male templates, but not from B. taurus male templates or female templates of either type. Male-specific sequences with homology to the RAPD also occur in B. taurus breeds. This suggests that the polymorphism may be due to base substitution(s) in an ILO1065 priming site, or insertion/deletion events either affecting priming sites or occurring between sites on the cattle Y chromosome. We have shown that cattle, whether of B. indicus or B. taurus phenotype, which possess a typically B. indicus metaphase Y chromosome on the basis of QFQ banding, have a B. indicus ILO1065-generated genotype. The ILO1065-primed RAPD can be used in a simple dot blot assay as a probe of RAPD-PCR products, to provide a convenient, reliable and effective means of detecting introgression of zebu genes in B. taurus cattle populations.

Immunosuppressive properties of cultured human cornea and ciliary body in normal and pathological conditions

Corneal transplantations may survive when transplanted orthotopically even in the presence of massive corneal neovascularization, while such grafts would be rejected in heterotopic locations. Experiments with murine tissues have shown that cultured corneal tissue as well as iris/ciliary body (I/CB) tissue produce immunosuppressive factors. This was not the case when traumatized corneas were tested. We therefore wondered whether the same difference could be observed when explants of normal or pathological human corneas or I/CB tissues were tested. Supernatant of cultured cornea and I/CB tissue was added to a mixed lymphocyte reaction (BALB/c responder and C57B1/6 stimulator cells) and thymidine incorporation was measured. Culture supernatants from normal corneas and corneas with bullous keratopathy achieved similar levels of MLR inhibition, which could not be blocked by addition of anti-transforming-growth factor-beta 2 antibody or indomethacin. The supernatant from cultured I/CB cells from normal eyes and from eyes containing a posterior segment melanoma did not differ in their immunosuppressive effect. The MLR inhibitory effect of supernatant from I/CB cells was partly blocked by addition of indomethacin. We conclude that MLR inhibiting factors are produced by normal and pathological corneas and by I/CB cells, but the supernatants from these tissues achieve their effect by different means. It is likely that the ability of cornea and I/CB tissues to produce immunosuppressive factors contributes to the success of orthotopic corneal transplants in man.

Time-integrated blood lead concentration is a valid surrogate for estimating the cumulative lead dose assessed by tibial lead measurement

The concentration of lead in tibia (Pb-T) was measured in vivo by a 109Cd K-shell X-ray fluorescence technique in 123 workers from a primary lead smelter (age: mean, 45 years; range, 30-61; duration of employment: mean, 20 years; range, 7-45). Their cumulative blood lead index (CBLI) was also calculated on the basis of the blood lead (Pb-B) records available from the company's medical files. Geometric mean for Pb-T was 49 micrograms Pb/g bone mineral (range, 15-167). The company's health surveillance programs, implemented since 1945, resulted in Pb-B values which rarely exceeded 70 micrograms Pb/dl whole blood. Pb-B at the time of Pb-T measurement averaged 31 micrograms Pb/dl (range, 6-62) and the geometric mean for CBLI amounted to 803 micrograms Pb/dl x year (range, 220-2130). Despite various assumptions and uncertainties inherent in the assessment of the cumulative lead dose through Pb-T measurement or CBLI calculation, the relation between both variables in the present lead smelter populations is very strong (rpearson = 0.80, P < 0.0001; age explained at the most 9.5% of the variance). The slope of the regression equation of log Pb-T vs log CBLI showed that a doubling of CBLI also corresponds to doubling of Pb-T. It may be concluded that a sound calculation of CBLI represents a valid surrogate for estimating the life time integrated dose of lead as assessed by the measurement of cortical bone lead (e.g., in tibia).

The insecticidal CryIB crystal protein of Bacillus thuringiensis ssp. thuringiensis has dual specificity to coleopteran and lepidopteran larvae

The crystals found in sporulation extracts of Bacillus thuringiensis (Berliner) contain proteins that are highly toxic to insects. Different crystal proteins exhibit distinct specificities for restricted groups of insects. An uncharacterized strain of B. thuringiensis (BtS2), derived from China, was found to carry several crystal protein genes and to be toxic to a wide variety of insects, including some coleopterans. Surprisingly, the coleopteran toxicity was traced to a CryIB-class protein. The previously cloned CryIB protein from B. thuringiensis ssp. thuringiensis strain HD-290-I, which was believed to be lepidopteran-specific, was also found to be toxic to at least two species of coleopteran larvae under certain conditions. In contrast to CryIB toxicity toward lepidopterans, the coleopteran activity of CryIB is enhanced by solubilization and by truncation with trypsin prior to administration. The magnitude of this effect varies with the host species and is reversed for the one lepidopteran tested. These results suggest that, for at least some insects, the apparent host specificity of CryIB may depend both on differences in midgut environment and on differences in toxin-receptor interaction. The results of insect toxicity experiments with a series of deletion mutants allowed definition of a CryIB protein fragment of ca. 65 kDa as the smallest peptide that retains bioactivity against both lepidopteran and coleopteran larvae. Deletions smaller than this resulted in the production of a protein that was nontoxic to both lepidopteran and coleopteran larvae.

Malaria imported into the United Kingdom in 1992 and 1993

A total of 1,629 cases of malaria were reported in the United Kingdom in 1992, and 1,922 cases in 1993, fewer than the peak of 2,332 reached in 1991. Of the 3,551 cases of malaria reported during 1992 and 1993, 74 were reported from Scotland, 45 from Wales, and 13 from Northern Ireland. Fourteen people died of falciparum malaria in the two years, 12 of whom contracted the disease in Africa and two in India. Preventive measures were inadequately followed by 12 of the 14 patients who died, eight of whom took no prophylaxis at all, and diagnosis was delayed in the other two. Over a third of the malaria cases were immigrants from endemic areas who had settled in the United Kingdom and who travelled to visit friends and relations. This was the commonest reason for travel given by cases, and correlates with a marked rise in falciparum malaria in settled immigrants from West Africa.

Renal function and hyperfiltration capacity in lead smelter workers with high bone lead

OBJECTIVE

The study was undertaken to assess whether the changes in urinary excretion of eicosanoids (a decrease of 6-keto-PGF1 alpha and PGF2 and an increase of thromboxane) previously found in lead (Pb) exposed workers may decrease the renal haemodynamic response to an acute oral protein load.

METHODS

The renal haemodynamic response was estimated by determining the capacity of the kidney to increase the glomerular filtration rate (in terms of creatinine clearance) after an acute consumption of cooked red meat (400 g). A cross sectional study was carried out in 76 male Pb workers (age range 30 to 60 years) and 68 controls matched for age, sex, socioeconomic state, general environment (residence), and workshift characteristics.

RESULTS

The Pb workers had been exposed to lead on average for 18 (range 6-36) years and showed a threefold higher body burden of Pb than the controls as estimated by in vivo measurements of tibial Pb concentration (Pb-T) (geometric mean 66 v 21 micrograms Pb/g bone mineral). The geometric mean concentrations of Pb in blood (Pb-B) and Pb in urine (Pb-U) were also significantly higher in the Pb group (Pb-B: 430 v 141 micrograms Pb/l; Pb-U: 40 v 7.5 micrograms Pb/g creatinine). These conditions of chronic exposure to Pb did not entail any significant changes in the concentration of blood borne and urinary markers of nephrotoxicity, such as urinary low and high molecular weight plasma derived proteins (beta 2-microglobulin, retinol binding protein, albumin, transferrin), urinary activities of N-acetyl-beta-D-glucosaminidase and kallikrein, and serum concentrations of creatinine, beta 2-microglobulin, urea, and uric acid. All participants also had normal baseline creatinine clearances (> 80 ml/min/1.73 m2) amounting on average to 115.5 in the controls v 121.3 ml/min/1.73 m2 in the Pb group. Both control and Pb exposed workers showed a significant increment in creatinine clearance (on average 15%) after oral protein load suggesting that the previously found changes in secretion of urinary eicosanoids apparently has no deleterious effect on renal haemodynamics in the examined Pb workers.

CONCLUSIONS

The finding that both baseline and stimulated creatinine clearance rates were not only significantly higher in the Pb workers but also positively correlated with Pb-T, suggests that moderate exposure to Pb may be associated with a slight hyperfiltration state, which has been found to attenuate the age related decline in baseline creatinine clearance by a factor of two. Although the relevance of this effect for the worker's health is unknown, it can be concluded that adverse renal changes are unlikely to occur in most adult male Pb workers when their blood Pb concentration is regularly kept below 700 micrograms Pb/l. One should, however, be cautious in extra-polating this conclusion to the general population because of pre-employment screening of the Pb workers for the absence of renal risk factors.

Fulminant hepatic failure resulting from coexistent Wilson's disease and hepatitis E

Fulminant hepatic failure resulting from hepatitis E and coexistent Wilson's disease was diagnosed in a six year old girl six weeks after returning from a holiday in India. Wilson's disease was diagnosed on the basis of histological evidence of hepatocellular copper deposition, confirmed by biochemical estimation of liver copper concentration. Although severely damaged, the liver was non-cirrhotic. Hepatitis E virus (HEV) was diagnosed by nested polymerase chain reaction, the specificity of which was confirmed by direct sequencing of amplified DNA. Replication of HEV within the liver at the time of diagnosis was confirmed by selective amplification of the antigenomic strand of the virus obtained from total liver RNA. The patient had an orthotopic liver transplantation without recurrence of hepatitis and remains well at 19 months. Viral excretion, recorded by serial amplification of HEV RNA extracted from stool samples, persisted for 30 days after liver grafting. Severe vitiligo, present preoperatively, dramatically improved after liver grafting and institution of immunosuppressive treatment. This case suggests that viral infection may play a part in the acute decompensation seen in some cases of Wilson's disease.

Hepatitis C and E in non-A non-B fulminant hepatic failure: a polymerase chain reaction and serological study

A significant proportion of patients with fulminant hepatic failure have clinical, biochemical and histological features suggestive of acute viral hepatitis, without serological evidence of either hepatitis A or B. The contribution of hepatitis C to such cases of non-A non-B fulminant hepatic failure is presently uncertain while hepatitis E is well recognized as a cause of fulminant hepatic failure in endemic areas. Nested polymerase chain reaction for detection of both hepatitis C and E virus as well as two serological assays for anti-hepatitis C virus and anti-hepatitis E virus western blotting (both IgG and IgM) were performed on acute sera of 42 consecutive cases of non A, non B-fulminant hepatic failure and on convalescent sera of 17 of 20 patients who underwent orthotopic liver transplantation. Fresh liver tissue, obtained at the time of transplantation, was also studied by polymerase chain reaction in eight cases. Evidence of an acute hepatitis E virus infection (hepatitis E virus RNA amplified from serum by polymerase chain reaction or serum IgM positive to western blot) was found in eight patients. One patient had anti-HCV at presentation but assays on later sera proved negative. Convalescent sera and sera obtained after orthotopic liver transplantation were all negative to both anti-HCV assay systems, but HCV RNA was not found in either serum or liver tissue in any case.(ABSTRACT TRUNCATED AT 250 WORDS)