Phylogenetic analysis of the human papillomavirus type 2 (HPV-2), HPV-27, and HPV-57 group, which is associated with common warts

Human papillomavirus types 2 (HPV-2), HPV-27, and HPV-57, are three closely related viruses within the phylogenetic supergroup formed by the remotely related genital papillomaviruses. In contrast to this phylogenetic association, these three viruses are most often found in common warts at nongenital sites, but also occasionally in genital warts and mucosal lesions of the nasopharyngeal cavity. We studied the genomic diversity of HPV sequences in skin warts presumably caused by these viruses. These biopsies were sampled from 75 patients living in Germany, Japan, or Singapore. Among 27 warts with HPV-2, we found seven new genomic variants and among 32 with HPV-57, eight new variants. In both cases, we did not detect the original prototype genomes. In contrast, 13 of 16 warts with HPV-27 contained the prototype genome, and only one new variant was found in three patients. We did not find variants clearly intermediate between any two types, although HPV-2 and HPV-27 are among the most closely related of the extent HPV types. We also did not detect novel HPV types, although the samples were examined with polymerase chain reaction protocols that would have detected remotely related HPVs. So we propose that the phylogenetic group formed by HPV-2, HPV-27, and HPV-57 has no or only very are additional members. One of the HPV-57 variants found, HPV-57-G44, was most likely identical to the subtype HPV-57b, previously proposed to be associated with nasal neoplasia, but found here frequently in common skin warts. Our publication establishes a foundation for pathological and phylogenetic comparisons of HPV types in skin warts.

Effects of ingredients on stability of captopril in extemporaneously prepared oral liquids

The stability of captopril in several extemporaneously prepared oral liquid formulations was studied. Captopril 1-mg/mL oral liquid formulations were prepared from either powder or tablets in two grades of water, syrup, methylcellulose, and edetate disodium. The liquids were stored at 5 degrees C in amber glass containers, and samples were removed at intervals up to 30 days for assay of captopril concentration by stability-indicating high-performance liquid chromatography. The pH of the formulations remained fairly stable for 30 days. In general, captopril was more stable in formulations containing captopril from tablets than from powder. Captopril in formulations in which the only vehicle was highly purified water was slightly but not significantly more stable than in formulations made with sterile water for irrigation. Formulations made with undiluted syrup were more stable than formulations in which water was used to dilute syrup or formulations containing methylcellulose. The formulations containing edetate disodium were much more stable than those that lacked this component. The stability of captopril 1 mg/mL in oral liquid formulations was influenced by the captopril source (tablets versus powder) and by the presence of syrup, methylcellulose, and edetate disodium. Captopril in a preparation made with tablets and undiluted syrup was stable for 30 days at 5 degrees C, and the formulation should be palatable.

Stability of admixtures of pethidine and metoclopramide in aqueous solution, 5% dextrose and 09% sodium chloride

OBJECTIVE

To study the stability of admixtures of pethidine and metoclopramide in aqueous solution, 0.9% sodium chloride and 5% dextrose preparations.

METHOD

Aqueous mixtures of 1 ml of 50 mg/ml pethidine with 2ml of 5 mg/ml metoclopramide were prepared in plastic syringes, while the 0.9% sodium chloride and 5% dextrose admixtures, each containing 7.35 mg/ml of pethidine and 0.15 mg/ml of metoclopramide, were prepared in infusion bags. The preparations were stored under light and dark conditions at 32 degrees C for 48 h. Samples were collected at 0, 0.5, 1, 2, 4, 6, 8, 24, 32 and 48 h. A high-performance liquid chromatographic method was developed to separate and quantify both drugs.

RESULTS

All preparations were found to be physically and chemically stable for at least 48h, as concentration changes were within 10% of their initial level, with no development of haze, precipitate or colour. Light appeared to have a negligible effect. Although pH changes were observed, they were inconsistent and were within the ranges in which the drugs are expected to remain stable. Pethidine and metoclopramide admixtures can, therefore, on stability grounds be used for the concomitant management of pain, nausea and vomiting.

Stability of phenoxybenzamine hydrochloride in various vehicles

The stability of phenoxybenzamine hydrochloride in various oral liquids was studied. Phenoxybenzamine hydrochloride powder or capsules were combined with various vehicles to prepare 10-mL formulations with a drug concentration of 2 mg/mL and a 20-mL stock solution containing 10 mg/mL. All formulations were prepared in triplicate and stored at 4 degrees C. A 1.0-mL sample of each of the 2-mg/mL formulations was withdrawn on days 0, 1, 2, 3, and 4, and samples of selected formulations were taken on days 7 and 10. Samples of the stock solution were withdrawn on days 0, 2, 4, 7, 10, 14, and 30. All samples were analyzed by high-performance liquid chromatography. Phenoxybenzamine hydrochloride 2 mg/mL was stable for a longer time in 1% propylene glycol, 0.15% citric acid, and water than in a similar vehicle in which syrup was used in place of water. The concentrations of the drug in both the 10-mg/mL stock solution and stock solutions diluted to 2 mg/mL were > 90% of the initial drug concentration for 30 days. Phenoxybenzamine hydrochloride 2 mg/mL in 1% propylene glycol and 0.15% citric acid in distilled water was stable for 7 days at 4 degrees C. A stock solution of phenoxybenzamine hydrochloride 10 mg/mL in propylene glycol was stable for 30 days at 4 degrees C and, after dilution with 66.7% sucrose in distilled water to a concentration of 2 mg/mL, for up to one hour at 4 degrees C.

Inhibition of the alloantibody response by CD95 ligand

We investigated the effect of Fas/APO1-ligand (CD95L) gene transfer on allogeneic immune responses in vivo. A colon carcinoma cell line from BALB/c mice, CT26, was stably transfected with a vector encoding mouse CD95L and was inoculated into C57BL/6 mice. CD95L expression markedly reduced allogeneic cytotoxic T lymphocyte and helper T lymphocyte activity directed toward CT26. Strikingly, expression of CD95L on these allogeneic tumors completely inhibited the generation of alloantibodies of both IgM and IgG subclasses. Thus, CD95L inhibited alloantibody production and conferred localized immune suppression through this mechanism. These results provide insight into the role of CD95L in regulating the alloantibody response and the generation of local immune responses.

Genomic diversity and evolution of papillomaviruses in rhesus monkeys

We are studying the diversity of and relationships among papillomaviruses (PVs) to understand the modes and timescales of PV evolution and in the hope of finding animal PVs that may serve as model systems for disease caused by human PVs (HPVs). Toward this goal, we have examined 326 genital samples from rhesus monkeys and long-tailed macaques with a PCR protocol optimized for detecting genital HPV types. In 28 of the rhesus monkey samples, we found amplicons derived from 12 different and novel PV genomes, RhPV-a to RhPV-m, with the likely taxonomic status of "type." The frequency with which novel RhPVs were detected suggests that rhesus monkeys may play host to PVs with a diversity similar to that of humans. In phylogenetic trees, all 12 of the different RhPVs and the previously described type RhPV-1 were members of the genital HPV supergroup and formed three minor branches distinct from the 11 branches formed by genital HPVs. We also identified a novel PV amplicon, MfPV-a, from a long-tailed macaque, a species belonging to the same genus as rhesus monkeys. MfPV-a turned out to be a close relative of five RhPVs. It appears that the evolution of primate lineages leading to the genus Macaca and to humans created transmission barriers for PVs, resulting in viral evolution closely linked to the host. Additional support for the linked-evolution hypothesis comes from considering the phylogenetic association of two other ape and monkey PVs with the genital HPVs, the supergroup formed by at least seven ungulate PVs, and the isolated phylogenetic position of the only known bird PV.

Genital papillomaviruses (PVs) and epidermodysplasia verruciformis PVs occur in the same monkey species: implications for PV evolution

Portions of the genome from two different papillomaviruses (PVs) of the Abyssinian Colobus monkey were sequenced and phylogenetically analyzed. This revealed that the major evolutionary separation between genital PVs and epidermodysplasia verruciformis-associated PVs (EV-PVs) hitherto found only in human papillomaviruses (HPVs) also exists in animal PVs. The sequence of the long control region (LCR) of Colobus monkey PV type 2 (CgPV-2) reveals a small size and an arrangement of potential cis-responsive elements typical of the EV-HPVs; namely four binding sites for the viral E2 protein, with one of them being located within the L1 gene, a cluster of nuclear factor I (NFI)- and AP-1-binding sites and a 50-bp sequence upstream of the E6 gene consisting only of the nucleotides A and T. This level of conservation of functional elements within the highly variable LCR suggests that CgPV-2 could be adopted as a model for studying human skin cancer associated with EV-HPVs. Although isolated from the same monkey species, the other Colobus monkey PV, CgPV-1, is a typical genital PV as shown by E1 and L1 sequence comparisons. The presence of these two major phylogenetic divisions of PVs in both human and monkey hosts strongly suggests that this diversification predated the evolutionary split between monkeys and apes. In other words, at least two different groups of PVs have been evolving separately in their respective primate hosts for more than 22 million years with only moderate sequence changes since their genesis.

Intrachain disulfide bond in the core hinge region of human IgG4

IgG is a tetrameric protein composed of two copies each of the light and heavy chains. The four-chain structure is maintained by strong noncovalent interactions between the amino-terminal half of pairs of heavy-light chains and between the carboxyl-terminal regions of the two heavy chains. In addition, interchain disulfide bonds link each heavy-light chain and also link the paired heavy chains. An engineered human IgG4 specific for human tumor necrosis factor-alpha (CDP571) is similar to human myeloma IgG4 in that it is secreted as both disulfide bonded tetramers (approximately 75% of the total amount of IgG) and as tetramers composed of nondisulfide bonded half-IgG4 (heavy chain disulfide bonded to light chain) molecules. However, when CDP571 was genetically engineered with a proline at residue 229 of the core hinge region rather than serine, CDP571 (S229P), or with an IgG1 rather than IgG4 hinge region, CDP571(gamma 1), only trace amounts of nondisulfide bonded half-IgG tetramers were observed. Trypsin digest reversephase HPLC peptide mapping studies of CDP571 and CDP571(gamma 1) with on-line electrospray ionization mass spectroscopy supplemented with Edman sequencing identified the chemical factor preventing inter-heavy chain disulfide bond formation between half-IgG molecules: the two cysteines in the IgG4 and IgG1 core hinge region (CPSCP and CPPCP, respectively) are capable of forming an intrachain disulfide bond. Conformational modeling studies on cyclic disulfide bonded CPSCP and CPPCP peptides yielded energy ranges for the low-energy conformations of 31-33 kcal/mol and 40-42 kcal/mol, respectively. In addition, higher torsion and angle bending energies were observed for the CPPCP peptide due to backbone constraints caused by the extra proline. These modeling results suggest a reason why a larger fraction of intrachain bonds are observed in IgG4 rather than IgG1 molecules: the serine in the core hinge region of IgG4 allows more hinge region flexibility than the proline of IgG1 and thus may permit formation of a stable intrachain disulfide bond more readily.

Novel methodology for echocardiographic quantification of cardiac shape

BACKGROUND

Left ventricular (LV) shape is a major determinant of cardiac physiology with important prognostic implications. Current techniques are limited in their ability to characterize shape. Regional curvature analysis is a recently developed method that is free of idealized shape assumptions and is applicable globally or regionally.

OBJECTIVE

To measure the change in regional curvature from diastole to systole to determine whether modifications of this methodology can be applied to study LV shape noninvasively, and to compare this method with other shape analysis methods.

ANIMALS

Seventeen normal dogs underwent transthoracic echocardiography. LV dimensions were measured at end-diastole and end-systole. LV endocardial outlines were traced from apical four-chamber views. LV short to long axis (D/L) ratios and eccentricity index (E) were calculated. Regional curvatures were determined using customized software. Reproducibility of regional curvature was also determined.

MAIN RESULTS

LV regional curvature values were consistent among animals at diastole and systole in all areas. Regional curvature showed divergence in different areas. D/L ratios showed a 7% decrease from diastole to systole, whereas E demonstrated a 10% increase. However, regional curvature exhibited a 39% change, suggesting that this methodology is more sensitive. Duplicate curvature values from same or different cardiac cycles were highly reproducible.

CONCLUSIONS

Quantitative regional curvature analysis can be applied with echocardiography to study LV shape. This methodology is more sensitive than current methods, is reproducible and may be applicable to the noninvasive study of shape changes in cardiac disease.

Differential effects of IL-12 receptor blockade with IL-12 p40 homodimer on the induction of CD4+ and CD8+ IFN-gamma-producing cells

The role of IL-12 role in regulating Th1/Th2 balance is attributed in part to the ability of this cytokine to induce IFNgamma production by NK and Th1 cells, which in turn promotes Th1 and inhibits Th2 development. In the present study, the requirement for IL-12 in the development of alloantigen-reactive Th1 was assessed by adding neutralizing anti-IL-12 Abs or the IL-12 receptor antagonist p40 homodimer to primary MLC. The resulting cell populations were assessed for Th1 development by measuring IFN-gamma production upon restimulation with alloantigens. While the addition of anti-IL-12 Abs to primary MLC did not influence subsequent cytokine production, addition of p40 homodimer markedly enhanced, rather than decreased, Th1 development. To determine which T cell population produced enhanced levels of IFN-gamma in response to p40 homodimer, CD4+ or CD8+ T cells were depleted from the MLC. While p40 homodimer was inhibitory to selected CD4+ Th1 development, it enhanced IFN-gamma production by CD8+ T cells. To test the in vivo relevance of these findings, mouse heterotopic cardiac allograft recipients were treated with either p40 homodimer, anti-CD8 mAb, or with both p40 homodimer and anti-CD8 mAb. Treatment of allograft recipients with p40 homodimer had no effect on the in vivo sensitization of IFN-gamma-producing cells and resulted in accelerated allograft rejection relative to unmodified recipients. However, p40 homodimer markedly prolonged allograft survival in mice depleted of CD8+ T cells. Hence, p40 homodimer stimulates CD8+ Th1 development in vitro but inhibits CD4+ T cell function both in vitro and in vivo.

Differential effects of IL-12 receptor blockade with IL-12 p40 homodimer on the induction of CD4+ and CD8+ IFN-gamma-producing cells

The role of IL-12 role in regulating Th1/Th2 balance is attributed in part to the ability of this cytokine to induce IFNgamma production by NK and Th1 cells, which in turn promotes Th1 and inhibits Th2 development. In the present study, the requirement for IL-12 in the development of alloantigen-reactive Th1 was assessed by adding neutralizing anti-IL-12 Abs or the IL-12 receptor antagonist p40 homodimer to primary MLC. The resulting cell populations were assessed for Th1 development by measuring IFN-gamma production upon restimulation with alloantigens. While the addition of anti-IL-12 Abs to primary MLC did not influence subsequent cytokine production, addition of p40 homodimer markedly enhanced, rather than decreased, Th1 development. To determine which T cell population produced enhanced levels of IFN-gamma in response to p40 homodimer, CD4+ or CD8+ T cells were depleted from the MLC. While p40 homodimer was inhibitory to selected CD4+ Th1 development, it enhanced IFN-gamma production by CD8+ T cells. To test the in vivo relevance of these findings, mouse heterotopic cardiac allograft recipients were treated with either p40 homodimer, anti-CD8 mAb, or with both p40 homodimer and anti-CD8 mAb. Treatment of allograft recipients with p40 homodimer had no effect on the in vivo sensitization of IFN-gamma-producing cells and resulted in accelerated allograft rejection relative to unmodified recipients. However, p40 homodimer markedly prolonged allograft survival in mice depleted of CD8+ T cells. Hence, p40 homodimer stimulates CD8+ Th1 development in vitro but inhibits CD4+ T cell function both in vitro and in vivo.

Locally advanced breast cancer: early results of a randomised trial of multimodal therapy versus initial hormone therapy

The aim of this study was to investigate initial treatment of locally advanced breast cancer. Patients were randomised to "multimodal" therapy (pre-operative chemotherapy, Patey mastectomy, flap irradiation and adjuvant hormone therapy) (n = 55), or initial "hormone" therapy (n = 53) with further therapy upon tumour progression. The objective response to chemotherapy was 57% (31/54) after four cycles. Of patients on hormone therapy, 36% (19/53) had an objective response and 32% (17/53) disease stasis at a 6 month assessment. At a median 30 months follow-up, there was no notable difference in development of metastases or survival: only 6 patients have uncontrolled loco-regional relapse (4 "hormonal", 2 "multimodal"). The number of treatments per patient required for this loco-regional control was lower in the "hormone" group (mean 2.13 versus 4.20 in the "multimodal" group). This small study has shown that the use of consecutive therapies, with the aim of tumour control, does not appear to compromise outcome in comparison with initial "multi-modal" therapy. Adopting such a policy may allow some patients to avoid unnecessary treatments.

Colorectal carcinoma in Hong Kong: epidemiology and genetic mutations

The incidence of colorectal carcinoma is rising at an alarming pace in Asian urban societies such as Hong Kong. Detailed examination of the epidemiological pattern and genetic mutation of colorectal cancer in the Hong Kong Chinese population is overdue. We compared the reported age incidence of colorectal carcinoma in Hong Kong with that of Scotland and other countries. Hong Kong showed a much higher incidence of colorectal carcinoma among the young age groups. By comparison with other countries, this raised incidence among the young appeared to be related to southern Chinese societies. The recent dramatic rise in colorectal cancer in Hong Kong was largely attributable to an increase in the over 50 years age group, while the young incidence remained unchanged. We also defined the mutation spectrum of p53 and Ki-ras in 67 unselected cases by direct DNA sequencing. Interestingly, insertion/deletion mutations in p53 from colorectal carcinoma in Hong Kong showed a significantly higher frequency (17.2%) than the Scottish data (0%) and the world database (6.6%), although the overall frequency of p53 mutation (43%) in Hong Kong was similar to others. The high incidence of colorectal carcinoma in young people and the raised proportion of frameshift mutations in p53 encourage further search for a genetic basis for susceptibility to this disease in the Hong Kong Chinese population.

Does a hypertonic saline load predict fluid retention in pacing induced heart failure?

OBJECTIVE

We examined the response to hypertonic saline challenge (SC) as a potential predictor of fluid retention during heart failure induced by rapid ventricular pacing.

METHODS

Twelve dogs (22 +/- 4 kg) were given an intra-arterial bolus of 30 ml of 20% saline after establishing baseline fluid intake and urine output (24 h). Dogs were classified according to whether they drank more (Group A) or less (Group B) than the amount required to dilute the s.c. to isotonicity. Fluid retention was then assessed during heart failure after rapid ventricular pacing according to a graded ordinal scale and correlated with the responses to s.c..

RESULTS

No difference was noted in baseline fluid intake (1112 +/- 236 ml in Group A vs. 809 +/- 129 ml in Group B). Five hours after s.c. cumulative water intake was significantly greater in Group A than in Group B (1018 +/- 136 vs. 591 +/- 17 ml) (P < 0.01). Urine sodium concentration was 113 +/- 11 and 124 +/- 28 mmol/l at baseline in Group A and B, respectively; increased to 190 +/- 21 and 295 +/- 59 mmol/l at 5 h and remained elevated 24 h after s.c., 177 +/- 60 and 274 +/- 55 mmol/l (both P < 0.01 for within-group comparisons vs. baseline). Urine sodium concentration was less in Group A than in Group B at 5 and 24 h (P < 0.05). The fluid retention score was greater in Group A (3.6 +/- 0.5) than in Group B (0.8 +/- 0.4) (P < 0.01). Fluid retention in heart failure correlated with water intake after the pre-pacing s.c. (r = 0.68, P < 0.025) and inversely with urine concentrating ability (r = -0.58, P < 0.05). Furthermore, water intake and urine concentrating ability following the s.c. were inversely related (r = -0.67, P < 0.02).

CONCLUSIONS

We conclude that normal dogs may be classified according to their fluid intake after s.c.. Those dogs that drank excessively and produced a dilute urine were more likely to retain fluid during pacing-induced heart failure. Hence, fluid intake and the ability to excrete a concentrated urine after a saline challenge may be useful variables to predict fluid retention in pacing-induced heart failure.

Identification of mutations in seven Chinese patients with X-linked chronic granulomatous disease

X-linked chronic granulomatous disease (CGD) is due to mutations in the gp91phox gene on Xp21.1. Studies in white and Japanese X-linked CGD patients have shown mutations in nearly every exon. We studied the molecular defect of seven Chinese patients with X-linked CGD from six unrelated families. Mutations were located by single-strand conformation polymorphism and then defined by sequence analysis. The mutations were two different amino acid substitutions, a nonsense mutation, an in-frame trinucleotide deletion, a single A insertion causing a frameshift, and a premature stop. Lastly, a rare splice site mutation caused by G to A transition at the terminal nucleotide of exon 3, resulting in the skipping of exon 3, was found. The possible effects of these mutations on protein structure-function or splicing were discussed. Together with previous reports, the A insertion in the run of six As from nucleotide 749 to 754 and the G to A transition at the terminal position of exon 3 may be mutation hotspots of the gp91phox gene. The extreme heterogeneous mutations found in our patients suggest the absence of ethnic group-specific mutation.

IL-12 antagonism induces T helper 2 responses, yet exacerbates cardiac allograft rejection. Evidence against a dominant protective role for T helper 2 cytokines in alloimmunity

IL-12 promotes Th1 development and inhibits the generation of Th2 by inducing IFN-gamma production. In several experimental models, Th2 are preferentially induced in the absence of IL-12. It was proposed that the preferential induction of Th2 by IL-12 antagonism would inhibit Th1-driven rejection responses, thereby promoting allograft acceptance. To test this possibility, mouse cardiac allograft recipients were treated with either anti-IL-12 Abs, or with the IL-12 receptor antagonist p40 homodimer. Unmodified rejection is characterized by a Th1-dominated response, with Th2 cytokines being absent or only weakly expressed within the allograft. Though both forms of IL-12 antagonism induced Th2 cytokine expression within the allograft, these treatments surprisingly exacerbated graft rejection relative to control animals. Interestingly, IL-12 antagonism did not inhibit IFN-gamma gene expression or in vivo sensitization of IFN-gamma-producing cells. Similar observations were made when IL-12 p40 knockout mice were used as allograft donors and recipients, verifying that IL-12 was not required for Th1 development. Further, IL-12 antagonism was associated with strong expression of p40 and weak expression of p35 within the graft. Neither p35 nor p40 mRNAs were detectable in control allografts. These data indicate that while IL-12 antagonism does induce Th2 cytokine expression within cardiac allografts, Th2 cytokines do not play a dominant protective role in the rejection process. Further, the Th2-inducing activity of IL-12 antagonism is not related to decreased IFN-gamma production, but may reflect altered regulation of IL-12 itself.

IL-12 antagonism induces T helper 2 responses, yet exacerbates cardiac allograft rejection. Evidence against a dominant protective role for T helper 2 cytokines in alloimmunity

IL-12 promotes Th1 development and inhibits the generation of Th2 by inducing IFN-gamma production. In several experimental models, Th2 are preferentially induced in the absence of IL-12. It was proposed that the preferential induction of Th2 by IL-12 antagonism would inhibit Th1-driven rejection responses, thereby promoting allograft acceptance. To test this possibility, mouse cardiac allograft recipients were treated with either anti-IL-12 Abs, or with the IL-12 receptor antagonist p40 homodimer. Unmodified rejection is characterized by a Th1-dominated response, with Th2 cytokines being absent or only weakly expressed within the allograft. Though both forms of IL-12 antagonism induced Th2 cytokine expression within the allograft, these treatments surprisingly exacerbated graft rejection relative to control animals. Interestingly, IL-12 antagonism did not inhibit IFN-gamma gene expression or in vivo sensitization of IFN-gamma-producing cells. Similar observations were made when IL-12 p40 knockout mice were used as allograft donors and recipients, verifying that IL-12 was not required for Th1 development. Further, IL-12 antagonism was associated with strong expression of p40 and weak expression of p35 within the graft. Neither p35 nor p40 mRNAs were detectable in control allografts. These data indicate that while IL-12 antagonism does induce Th2 cytokine expression within cardiac allografts, Th2 cytokines do not play a dominant protective role in the rejection process. Further, the Th2-inducing activity of IL-12 antagonism is not related to decreased IFN-gamma production, but may reflect altered regulation of IL-12 itself.

Allogeneic class I MHC requirement for alloantigen-reactive helper T-lymphocyte responses in vivo. Evidence for indirect presentation of alloantigen

The mechanisms by which host T cells recognize transplant-associated alloantigens in vivo have not been established. Two alloantigen presentation pathways may be used: (1) allogeneic class I and class II MHC molecules may be recognized directly by host CD8+ and CD4+ cells, respectively, or (2) allogeneic MHC molecules may be processed as foreign peptide and presented by host antigen-presenting cells to CD4+ cells in the context of self class II proteins. In this study, the sponge matrix allograft model was used to examine the relative contributions of these alloantigen presentation pathways to CD4+ T-cell activation in vivo. Limiting dilution analysis was used to quantify the localization of interleukin-2-producing helper T lymphocytes (HTL) following implantation of sponge allografts. Allografts either were disparate at both class I and class 11, or were derived from beta2-microglobulin knockout (beta2M-/-) mice, which express class II but are deficient in class I. Two measures of in vivo HTL function were monitored: (1) the accumulation of HTL within the allograft (a process that is dependent upon antigen-driven cytokine production), and (2) the development of cytolytic alloantibodies. After implantation of sponge allografts expressing both class I and class II, HTL were readily detectable in the allograft, and cytolytic alloantibodies were present in the serum. When mice were implanted with beta2M-/- sponge allografts, HTL failed to infiltrate these class I-deficient allografts, and alloantibodies were not detectable in the sera of recipients of beta2M-/- sponge allografts. This in vivo requirement for class I expression was not reflected by traditional in vitro measures of HTL function; cells obtained from lymphoid tissues mounted a mixed lymphocyte response and produced interleukin-2 when stimulated with beta2M-/- splenocytes in vitro. One possible interpretation of these data is that in vivo HTL functions are dependent upon the presence of class I-reactive CD8+ T cells. However, HTL readily infiltrated grafts expressing both class I and class II when recipients depleted of CD8+ T cells, and alloantibodies were produced. These observations support the idea that indirect presentation of allogeneic class I molecules plays a critical role in regulating CD4+ HTL functions associated with allograft rejection in vivo.

Tension pneumoperitoneum

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Mannose-binding protein in preterm infants: developmental profile and clinical significance

The aim of this study was to determine the developmental profile of mannose-binding protein (MBP) in preterm infants. MBP was measured in 885 longitudinally collected serum samples from 168 preterm infants, and 63 were genotyped with respect to the codon 54 mutation in the MBP gene. MBP level/codon 54 genotyping were also determined on the cord blood of 146/123 term infants and 138/123 adults, respectively. The best cut-off values of MBP for dividing preterm, term infants and adults into 'low' and 'high' MBP groups were 400 ng/ml (55 low, 113 high), 700 ng/ml (35 low, 111 high) and 750 ng/ml (33 low, 105 high), respectively, by achieving the least number of misclassifications according to the codon 54 mutation. The relative risk of the 'low' groups for presence of the codon 54 mutation compared with 'high' groups were 42.4, 67.9 and 22.9 for preterm, term infants and adults, respectively (P < 0.00001). The gestational age and birth weight of the 'low' (n = 55) and 'high' (n = 113) MBP groups of the 168 preterm infants were 29.5 +/- 2.8 weeks, 30.5 +/- 2.8 weeks (P = 0.03) and 1230 +/- 317 g, 1277 +/- 289 g (P = 0.35), respectively. The mean MBP levels of these two groups of preterm infants were different (P < 0.001) at all ages measured. As a whole group, the MBP level rose from a mean of 500 ng/ml at 25 weeks gestation to 1700 ng/ml at 20 weeks post full-term. The mortality rates of 'low' and 'high' MBP groups of preterm infants were 22% and 12%, respectively (P = 0.113). This difference in mortality was due to gestational age and birth weight standard deviation score (SDS) after adjusting for length of gestation and gender (P = 0.0001) rather than to low MBP levels (P = 0.65). MBP levels were not related to birthweight SDS score (P = 0.26). The mean +/- s.d. MBP levels for preterm, term infants and adults without the codon 54 mutation were 1225 +/- 701 ng/ml (n = 45), 2064 +/- 829 ng/ml (n = 88) and 2473 +/- 1395 ng/ml (n = 95), respectively; the corresponding values for those with the codon 54 mutation were 130 +/- 275 ng/ml (n = 18), 533 +/- 665 ng/ml (n = 35) and 330 +/- 225 ng/ml (n = 28), respectively. Intra-uterine growth retardation in preterm infants does not influence MBP levels. For those without the codon 54 mutation, there is a significant difference in MBP level between the three age groups. For those with the codon 54 mutation, there is a significant difference between preterm and term infants, but not between term infants and adults. We conclude that there is a maturation in MBP levels for preterm infants, and that a moderately low MBP phenotype does not affect survival. We cannot exclude an effect of profoundly reduced MBP levels (characteristic of individuals homozygous for the codon 54 mutation), since no such preterm infant was identified in this study.

In situ detection of Epstein-Barr virus in non-small cell lung carcinomas

Epstein-Barr virus (EBV) is strongly associated with nasopharyngeal carcinoma and lymphoepithelioma-like carcinomas (LELC) of foregut-derived organs. Recently this group of EBV-associated carcinomas has been expanded by the identification of the virus in conventional adenocarcinomas of the stomach. In situ hybridization (ISH) using a sensitive digoxigenin-labelled EBER RNA probe was performed on 167 consecutive unselected primary non-small cell lung carcinomas, to determine the frequency of EBV association in these tumours. Nine cases (5.4 per cent) showed strong EBER signals in the tumour cell nuclei. By immunohistochemistry, four of the EBER-positive tumours showed patchy expression of the viral latent membrane protein (LMP-1) and none showed any expression of the EBV nuclear antigen 2 (EBNA2). Morphologically, all the positive tumours were LELC, whereas no conventional type of non-small cell lung carcinoma showed EBV association. The LELC presented a morphological spectrum from undifferentiated to squamoid or glandular differentiation. The patients showed a male to female ratio of 8:1. The mean age at presentation was 48 years. Smoking was not a risk factor. All patients were alive at follow-up periods of 23-52 months. Southern blot analysis performed on eight of the nine positive tumours showed a clonal episomal form of EBV, suggesting the clonal expansion of an infected tumour cell early in oncogenesis. These characteristics of the EBV-associated lung tumours justify their consideration as a distinct clinicopathological entity.