Masking of irregular corneal topography with contact lenses

PURPOSE

We examined the effectiveness of various types of contact lenses in masking irregular corneal topography using videokeratoscopy, residual aberrations, and measurement of visual acuity.

METHODS

Thirteen subjects with differing degrees of keratoconus were recruited. Four types of soft lenses were used that varied in both thickness and water content, along with a rigid gas permeable (RGP) and a flexible gas permeable contact lens.

RESULTS

RGP contact lenses provided the best visual acuity and the least residual aberrations. Flexible gas permeable lenses showed a reasonable masking of corneal distortion but did not provide the expected improvement in visual acuity. Soft contact lenses provided marginally better visual acuity than spectacle correction, but the level of residual aberrations was still high, even for relatively thick soft lenses (up to 0.2 mm). A significant correlation existed between the regularity of the front surface of the contact lenses on the eye and visual acuity in low illumination.

CONCLUSIONS

Among the currently available contact lens materials, RGP lenses provide the best visual performance for subjects with keratoconus.

Retroviral vector targeting to melanoma cells by single-chain antibody incorporation in envelope

Two strategies for targeting recombinant retroviruses to melanoma cells were compared. One was to extend the tropism of an ecotropic envelope to human melanoma cells, the other was to enhance the tropism of an amphotropic envelope for melanoma cells. Chimeric retroviral envelopes, incorporating a single-chain antibody (ScFv) directed against high-molecular-weight melanoma-associated antigen (HMWMAA) at the amino terminus are correctly processed and incorporated into virions. ScFv-ecotropic envelope chimeras allow specific, but low-titer, targeting of HMWMAA-positive cells, when co-expressed with ecotropic envelopes. ScFv-amphotropic envelope chimeras bind specifically to HMWMAA-positive cells and allow preferential infection at high titer.

Quantitation of hepatitis G and C viruses in the liver: evidence that hepatitis G virus is not hepatotropic

Hepatitis G virus (HGV) is prevalent in patients with chronic liver disease and has been previously detected in liver specimens. However, it is unknown whether the virus is replicating in the liver or is simply a contaminant from serum. We sought to determine whether HGV was hepatotropic and to determine whether coinfection with HGV and hepatitis C virus (HCV) influenced the level of either virus. Virus was quantitated using branched DNA (bDNA) assay for both HGV and HCV in the liver explants and pretransplant serum samples from 30 transplant recipients: Group I, HGV/HCV coinfection (n = 10); group II, HCV infection alone, (n = 8); group III, HGV alone (n = 12). In patients with coinfection HCV (RNA) titers in liver were consistently higher than those for HGV RNA (median 1.13 x 10(8) and 360,000 Eq/g respectively, P < .01). The ratio of liver/serum viral RNA was significantly higher for HCV than for HGV (median 129 and 0.3 respectively, P < .01). Levels of HCV RNA were similar in patients with HCV infection alone versus those with HGV/HCV coinfection (median; liver = 1.15 x 10(7) vs. 1.13 x 10(8) Eq/g, serum = 500,000 vs. 200,000 Eq/mL) and levels of HGV RNA in liver and serum were similar in patients with HGV infection alone compared to those with HGV/HCV coinfection (median; liver = 1.2 x 10(6) vs. 4.0 x 10(5) Eq/g, serum = 4.5 x 106 vs. 2.6 x 10(6) Eq/mL). Levels of either virus appeared unaffected by the presence of an additional virus. The high ratio of HCV RNA levels in liver compared to serum is consistent with its known hepatotropism, but this pattern was not observed for HGV. The median liver/serum ratio of HGV RNA was less than unity, a finding consistent with serum contamination of liver tissue. Thus we conclude that the liver is not the main site of HGV replication.

IL-13, IL-4Ralpha, and Stat6 are required for the expulsion of the gastrointestinal nematode parasite Nippostrongylus brasiliensis

Although IL-4 induces expulsion of the gastrointestinal nematode parasite, Nippostrongylus brasiliensis, from immunodeficient mice, this parasite is expelled normally by IL-4-deficient mice. This apparent paradox is explained by observations that IL-4 receptor alpha chain (IL-4Ralpha)-deficient mice and Stat6-deficient mice fail to expel N. brasiliensis, and a specific antagonist for IL-13, another activator of Stat6 through IL-4Ralpha, prevents worm expulsion. Thus, N. brasiliensis expulsion requires signaling via IL-4Ralpha and Stat6, and IL-13 may be more important than IL-4 as an inducer of the Stat6 signaling that leads to worm expulsion. Additional observations made in the course of these experiments demonstrate that Stat6 signaling is not required for IL-4 enhancement of IgG1 production and actually inhibits IL-4-induction of mucosal mastocytosis.

Hepatitis G virus infection in patients transplanted for cryptogenic cirrhosis: red flag or red herring?

BACKGROUND

The significance of hepatitis G (HGV) infection in liver transplant recipients is not known. We set out to determine the pre-orthotopic liver transplantation (OLT) prevalence, the pre- and postoperative viral titers of HGV, and the allograft histology in patients infected with HGV who underwent OLT for cryptogenic cirrhosis.

METHODS

HGV RNA was measured using a research-based branched DNA assay. The assay used a target-specific probe set that was based on the 5'-untranslated region of the HGV genome. Allograft histology was assessed with protocol liver biopsies in all patients who survived longer than 6 months.

RESULTS

The preoperative prevalence of HGV infection in recipients transplanted for cryptogenic cirrhosis was 26%. Thirty-seven percent (12 of 33) of recipients who had serum available in the first postoperative month had HGV infection. Mean HGV RNA levels were 9.8 (+/-4.2) (viral molecular equivalents/ml x 10[6]) before OLT and 37.5 (+/-10.7) at 1 year after OLT. In 4 of the 11 cryptogenic recipients in whom HGV RNA was detectable in the first postoperative month, HGV RNA fell to undetectable levels at the most recent follow-up (mean 70 months). Of the five cryptogenic recipients who continue to have measurable HGV RNA, three have unexplained hepatitis histologically.

CONCLUSIONS

These findings suggest the following: 1) The prevalence of HGV infection in patients undergoing OLT for cryptogenic cirrhosis is about 25%. 2) In recipients persistently infected with HGV, mean HGV RNA titers increase after OLT. 3) HGV RNA becomes undetectable in about one third of recipients who had detectable HGV RNA in the first month after OLT. 4) Hepatitis of uncertain etiology occurs in 60% (3 of 5) of persistently HGV-infected cryptogenic recipients.

Heteroclitic proliferative responses and changes in cytokine profile induced by altered peptides: implications for autoimmunity

Productive engagement of T cell receptors (TCRs) by cognate ligand (major histocompatibility complex plus peptide) leads to proliferation, differentiation, and the elaboration of effector functions. Altered peptides generated by single amino acid substitutions in the antigenic peptide have diverse effects on the outcome of the T cell response. We have generated an altered peptide (Q144) from an autoantigenic peptide of myelin proteolipid protein 139-151 by a single amino acid substitution (from tryptophan to glutamine) in the primary TCR contact at position 144 that is capable of inducing CD4(+) T cell responses in H-2(s) mice. By using a Q144-specific T cell clone (Q1.1B6), we see a hierarchy in T cell proliferation and cytokine production with various position 144 substituted peptides and have identified a peptide (L144) that hyperstimulates this T cell clone. In contrast to Q144, L144 induces maximal proliferation at 7 logs lower antigen concentration, induces greater cell death at higher antigen dose, and induces the secretion of cytokines not detected following stimulation with the cognate ligand. This heteroclitic T cell response associated with changes in cytokine profile was observed with several other T cell clones of different specificities. The L144 peptide also induces costimulation independent proliferation and cytokine production from the Q1.1B6 T cell clone. We describe this as a superagonist response. Such responses may have a role in the initiation of autoimmunity by promoting a proinflammatory environment following ligation of a cross-reactive TCR on autoreactive T cells.

Screening and chemoprophylaxis for tuberculosis infection in college populations

Active tuberculosis and the potential for widespread disease exist on college campuses. To maximize the benefit and minimize the potential harm of a screening program, health service clinicians should administer tuberculin skin tests to high-risk students only. Those found to be infected should be considered for prophylactic treatment. The criteria that identify students as being at high risk need to be clearly appreciated, especially the issue of birth outside the United States. Certain countries of origin pose a high risk; others do not. By understanding the fundamentals of the current pandemic and employing a consistent approach, college health professionals can make the correct screening decisions, thereby reducing the risk to their campus communities and assisting in the eradication of this preventable disease.

Dissociation of cytokine signals for proliferation and apoptosis

Cytokines such as IL-2 or IL-3 prevent cell death through apoptosis, either by preventing apoptosis directly or by sensitizing cells to survival factors present in serum. We demonstrate herein that BAF-B03 cells transfected with the wild-type IL-2R beta-chain undergo apoptosis when stimulated with IL-2 or IL-3 in the absence of serum. IL-2 also induced apoptosis in normal IL-2-responsive human T cell blasts in the absence of serum, and furthermore, epidermal growth factor and fibroblast growth factor induced increased rates of apoptosis in fibroblasts in the absence of serum, suggesting that cytokine-induced apoptosis in the absence of serum survival factors might represent an important biologic phenomenon. In the presence or the absence of serum, IL-2 and IL-3 induced expression of both c-Myc and Bax. In contrast, optimal cytokine-induced expression of Bcl-2 requires serum. Constitutive expression of Bcl-2 prevented cytokine-induced apoptosis. Transferrin mimicked serum by inducing an increase in Bcl-2 expression levels and concurrently prevented apoptosis. These results suggest that the balance between cytokine- and serum-induced Bcl-2 expression and cytokine-induced Bax expression may determine whether a cell undergoes cytokine-induced apoptosis. In BAF/BO3 cells expressing a mutant IL-2Rbeta with a deletion of the acidic domain, IL-2 did not induce either Bax expression or apoptosis. This suggests that the acidic domain of the IL-2R beta-chain plays an essential role in regulating IL-2-mediated Bax expression and apoptosis. Cytokine-induced apoptosis and its counterbalance by survival factors present in serum may play an important role in the regulation of cellular homeostasis during pathophysiologic processes.

Dissociation of cytokine signals for proliferation and apoptosis

Cytokines such as IL-2 or IL-3 prevent cell death through apoptosis, either by preventing apoptosis directly or by sensitizing cells to survival factors present in serum. We demonstrate herein that BAF-B03 cells transfected with the wild-type IL-2R beta-chain undergo apoptosis when stimulated with IL-2 or IL-3 in the absence of serum. IL-2 also induced apoptosis in normal IL-2-responsive human T cell blasts in the absence of serum, and furthermore, epidermal growth factor and fibroblast growth factor induced increased rates of apoptosis in fibroblasts in the absence of serum, suggesting that cytokine-induced apoptosis in the absence of serum survival factors might represent an important biologic phenomenon. In the presence or the absence of serum, IL-2 and IL-3 induced expression of both c-Myc and Bax. In contrast, optimal cytokine-induced expression of Bcl-2 requires serum. Constitutive expression of Bcl-2 prevented cytokine-induced apoptosis. Transferrin mimicked serum by inducing an increase in Bcl-2 expression levels and concurrently prevented apoptosis. These results suggest that the balance between cytokine- and serum-induced Bcl-2 expression and cytokine-induced Bax expression may determine whether a cell undergoes cytokine-induced apoptosis. In BAF/BO3 cells expressing a mutant IL-2Rbeta with a deletion of the acidic domain, IL-2 did not induce either Bax expression or apoptosis. This suggests that the acidic domain of the IL-2R beta-chain plays an essential role in regulating IL-2-mediated Bax expression and apoptosis. Cytokine-induced apoptosis and its counterbalance by survival factors present in serum may play an important role in the regulation of cellular homeostasis during pathophysiologic processes.

GC-MS-MS confirmation of unusually high delta 9-tetrahydrocannabinol levels in two postmortem blood samples

Unusually high levels of delta 9-tetrahydrocannabinol (delta 9-THC) were detected in two postmortem blood samples. Because of sample decomposition, the major metabolite, 11-nor-9-carboxy-tetrahydrocannabinol (delta 9-THCCOOH), could not be determined using the routine EI-MS technique, which cast some doubt on the delta 9-THC result. Analysis of the sample extracts by GC-MS-MS confirmed the presence of delta 9-THC, although no delta 9-THCCOOH was detected.

Hepatitis C and G co-infection: response to interferon therapy and quantitative changes in serum HGV-RNA

Hepatitis G virus (HGV), a positive sense RNA virus, is distantly related to hepatitis C virus (HCV): its genetic organization and identity are consistent with the Flaviviridae family. Coinfection with HGV occurs in 10% to 20% of HCV-infected subjects. These similarities raise two theoretical questions. First, could HGV coinfection play any role in the response of HCV to antiviral therapy and second, would this coinfected population have changes in serum HGV-RNA induced by interferon. To address these questions, 98 patients with documented chronic HCV underwent interferon therapy (3 million units three times a week) for 6 months. Response to therapy was categorized using standard biochemical criteria. Changes in HGV-RNA levels were evaluated before, during, and after interferon therapy by a quantitative branched DNA amplification research-based assay. Eleven of 98 (11%) patients with HCV infection had detectable serum HGV-RNA. There was no difference between the groups (HGV+ vs. HGV-) when baseline alanine aminotransferase (ALT) values, HCV-RNA levels, HCV genotype, histological severity, or other demographic features were analyzed. Interferon response was similar in both groups and HGV was not associated with outcome following therapy. Antiviral therapy appeared to induce a reduction in HGV-RNA load in five of nine patients coinfected with HCV serially tested. In two patients, the fall in serum HGV-RNA correlated with biochemical response, independent of changes in HCV-RNA. These observations indicate that a larger study of an HGV population is required to more clearly define the relationship between HCV and HGV coinfection and their response to antiviral therapy.

A role for JNK/SAPK in proliferation, but not apoptosis, of IL-3-dependent cells

Activation of c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) has been implicated in the induction of apoptosis in a variety of systems [1] [2] [3] [4] [5] [6] [7] [8]. BAF3 cells are pre-B cells that undergo apoptosis following IL-3 withdrawal or ceramide treatment [9] [10]. JNK/SAPK in BAF3 cells is stimulated by ceramide and also during cell proliferation in response to IL-3 [11], but its role in the apoptotic response is not clear. We have devised a method of selectively inhibiting JNK/SAPK activity using a dual-specificity threonine/tyrosine phosphatase, M3/6. Expression of this phosphatase in BAF3 cells prevented ceramide stimulation of JNK/SAPK activity but did not affect apoptosis following IL-3 withdrawal or ceramide treatment. IL-3-stimulated proliferation of BAF3 cells expressing the phosphatase was, however, inhibited. Hence JNK/SAPK activation is likely to be involved in the proliferative response of these cells but is not required for apoptosis. Selective ablation by dual-specificity phosphatases should be a general method for determining the functions of specific mitogen-activated kinase pathways.

The epidemiology of meningococcal disease in England and Wales, 1996 and 1997

Surveillance of meningococcal infection in England and Wales relies on three sources of data. Doctors are required by statute to notify clinically diagnosed cases of meningococcal meningitis and, since 1989, cases of meningococcal septicaemia (in the abse

What do children aged 5 to 11 years old know about the sun and skin cancer? The practical difficulties of international collaborative research when analysis of language is involved

The objective of this study was to determine the perceptions of primary school children about sun exposure and skin cancer, and the language they use about these issues, as a basis for the design of health promotional materials. In all, 2857 children in five European countries took part in the study and were compared with 641 Australian children participating in a similar study, since the latter have been exposed to more intensive health education about the sun. The 'draw and write' technique was used. In Europe the level of awareness about the risks of excessive sun exposure and the need to protect the skin was considerably lower than in Australia, although there was some variation within northern Europe. Amongst the European children acknowledging a need to protect the skin, the principal means of protection quoted was the use of suncreams, with inadequate awareness of the value of clothing, hats and shade. European children expressed greater approval of suntans than did the Australian children. Some methodological problems were encountered as a result of nuances in the languages involved, emphasizing difficulties in international research of this type.

CP-101,606, a potent neuroprotectant selective for forebrain neurons

The neuroprotective activity of (1S,2S)-1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol (CP-101,606), an N-methyl-D-aspartate (NMDA) receptor antagonist structurally similar to ((+/-)-(R*,S*)-alpha-(4-hydroxyphenyl)-beta-methyl-4-(phenylmethyl)-1-++ +piperidineethanol (ifenprodil), was investigated in neurons in primary culture. CP-101,606 potently and efficaciously protected hippocampal neurons from glutamate toxicity but was > 900-fold less effective for cerebellar granule neurons. The neuroprotective activity in the hippocampal neurons is mediated through a high affinity binding site distinct from the agonist and thienylcyclohexylpiperidine (TCP) binding sites of the NMDA receptor. Autoradiography indicates the CP-101,606 binding site is localized in forebrain, most notably in hippocampus and the outer layers of cortex. The functional selectivity for hippocampal neurons, forebrain localization of binding sites, and structural relation to ifenprodil suggest that CP-101,606 is an NMDA antagonist highly selective for NR2B subunit containing receptors.

bFGF induces BCK promoter-driven expression in muscle via increased binding of a nuclear protein

Changes in gene expression occurring during skeletal muscle differentiation are exemplified by downregulation of brain creatine kinase (BCK) and induction of muscle creatine kinase (MCK). Although both are transcriptionally regulated, there appears to be no transcription factor-element overlap, suggesting that their coordinate expression results from culture medium-related influences. Basic fibroblast growth factor (bFGF) prevents myogenesis and represses MCK expression by inhibiting transcriptional activation. It was hypothesized that bFGF similarly influenced BCK by inducing its expression. Accordingly, BCK promoter constructs were transiently transfected into C2C12 cells and, after a switch to differentiation medium, were treated with bFGF, bFGF plus herbimycin, adenosine 3',5'-cyclic monophosphate (cAMP), or phorbol 12-myristate 13-acetate (PMA). Analyses demonstrated that bFGF responsiveness was contained within a 33-base pair element. Electromobility shift assays showed that bFGF induction increased the abundance of the nuclear factor binding the element. Both effects were prevented by herbimycin. Neither cAMP nor PMA specifically induced the construct containing the bFGF-responsive element. The induced factor required phosphorylation to bind, implying that bFGF-mediated increases in binding may be due to transcription factor phosphorylation.

Influence of hepatitis G virus infection on the severity of liver disease and response to interferon-alpha in patients with chronic hepatitis C

BACKGROUND

Dual infection with hepatitis G virus (HGV) and hepatitis C virus (HCV) is common. The effect of HGV infection on chronic hepatitis C is not well known.

OBJECTIVE

To assess the prevalence of HGV infection; the effect of HGV infection on the clinical, virologic and histologic features of patients with chronic hepatitis C treated with interferon-alpha; and the influence of HGV infection on response to interferon-alpha therapy.

DESIGN

Retrospective study.

SETTING

A university hospital in France.

PATIENTS

228 patients with chronic hepatitis C treated with interferon-alpha (3 million U or 5 million U subcutaneously 3 times a week for 3, 6, or 12 months).

MEASUREMENTS

Before initiation of treatment, serum HGV RNA and serum HCV RNA were detected with branched-DNA assays and HCV genotype was determined with a line probe assay. Serum HGV RNA and serum HCV RNA were detected by polymerase chain reaction at the end of treatment and 6 months after treatment.

RESULTS

Infection with HGV was detected in 21% of patients and 32% of intravenous drug users. The median serum HGV RNA level was 33 x 10(6) genome equivalents/mL. Infection with HGV was more frequently found in men with a history of intravenous drug use and was associated with HCV genotype 3a (P = 0.02) independent of the source of infection. Serum HCV RNA levels, liver histologic findings, and response to interferon-alpha therapy did not differ between patients with and those without HGV infection. The loss of serum HGV RNA was not correlated with the biochemical response contrarily to the loss of serum HCV RNA.

CONCLUSIONS

Infection with HGV occurred frequently in this sample of patients with chronic hepatitis C, especially in patients infected with HCV genotype 3a. The level of HGV viremia was high relative to the level of HCV viremia. Infection with HGV did not influence the severity of liver disease or response to interferon-alpha therapy.