The mechanics of the collateral ligaments in the metacarpophalangeal joints: A scoping review

BACKGROUND

The metacarpophalangeal (MCP) joint's collateral ligaments have been extensively debated, with no clear consensus on their mechanics. Understanding their function is crucial for comprehending joint movement and stability.

METHODS

A thorough search was conducted across databases, including PubMed, Scopus, Cochrane library and grey literature. A total of 59 articles were identified, and after rigorous evaluation, six articles were included in the review.

RESULTS

The analysis underscores two principal findings. Firstly, the principal and accessory collateral ligaments exhibit consistent tension influenced by the MCP joint's position. This tension varies across different sections of the ligaments. Secondly, the ligaments' interaction with the joint structure plays a pivotal role in defining the range of motion of the joint.

CONCLUSION

Preliminary findings from this review indicate that MCP joint collateral ligament tension varies with joint position. Increased tension in the principal collateral ligament during flexion and isometric behavior of its volar portion in extension are observed. The accessory ligament may tighten during extension. The shape of the metacarpal head appears to influence this tension. These insights, while informative, call for further detailed research to deepen our understanding of MCP joint mechanics.

DNA-based discrimination and frequency of phytoplasma infection in the two hawthorn-feeding species, Cacopsylla melanoneura and Cacopsylla affinis, in northwestern Italy

A molecular tool, focused on the mitochondrial Control Region (CR), was developed to discriminate the two hawthorn-feeding psyllid species, Cacopsylla melanoneura (Förster) and C. affinis (Löw), and to estimate their frequencies in mixed populations. The test was carried out in paired and single-tube amplifications and validated analysing 52 male specimens previously determined by morphological analysis. The frequencies of the two species in mixed populations in the Aosta Valley (northwestern Italy) were analysed. The presence and type of 16SrX-group phytoplasmas was detected by nested PCR and RFLP tests in both species. C. melanoneura was the predominant species (86.5%; 80.4-91.2 CI); of these, 0.9% of the samples were positive for 'Ca. Phytoplasma mali' and 1.8% for 'Ca. Phytoplasma pyri'. One of 21 specimens of C. affinis was positive for 'Ca. Phytoplasma pyri'. The test also allowed us to identify two genetic variants of C. melanoneura, depending on the presence or absence of a 56 bp indel; these were named WI (with indel) and WOI (without indel), respectively. Further analyses were carried out on C. melanoneura specimens collected in apple orchards at six different locations in northern Italy where different levels of transmission efficiency have been described. Our preliminary observations suggest that some differences might exist between the two genetic variants in their ability to transmit phytoplasmas and to colonise different host plants.

Seasonal progression of sex ratio and phytoplasma infection in Scaphoideus titanus Ball (Hemiptera: Cicadellidae)

The differences between the seasonal occurrence and likelihood of being infected by FD phytoplasmas, of male and female Scaphoideus titanus Ball, were investigated. Sex ratio (male: female) was calculated by counting males and females sampled by means of yellow sticky traps and sweep-nets and from adults derived from hatched eggs in field-collected grapevine wood. PCR essays were performed to test differences in infection between genders. Overall, the sex ratio on sticky traps was significantly more male biased (1.99:1) if compared to net sweeping (0.62:1) and laboratory rearing (0.60:1). The peak of male presence was recorded in the middle of July in laboratory rearing and sweep net, and in the middle of August on sticky traps; the maximum presence of females was detected at the end of July in laboratory rearing, and at the end of August in sweep net samplings and on sticky traps. The seasonal sex ratio was more male biased at the beginning in laboratory rearing (1.50:1) and sticky traps (9:1), and then decreased in favor of females at the end of the sampling period, both in laboratory rearing (0.17:1) and in sticky traps (0.07:1). This trend was significantly less skewed, although similar, in sweep net samplings that recorded a sex ratio of 1:1 and 0.16:1 at the beginning and at the end of the sampling period, respectively. Concerning phytoplasma detection, an interaction between gender and sampling period was observed, the males showing a peak of infected individuals later in the season (35%). Some possible behavioral explanations of the data obtained are given.

Plasma HHV-8 viral load in HHV-8-related lymphoproliferative disorders associated with HIV infection

This is a mono-institutional analysis of the clinical features, immunological and virological findings, and prognostic factors of patients with HIV infection and HHV-8-lymphoproliferative disorders. Patients with Multicentric Castleman Disease and HHV-8-related lymphoma diagnosed and treated from April 1987 to June 2004 were included in the study. HHV-8 and HIV plasma viral load, CD4+ count, hematologic parameters, and general wellbeing (performance status) were assessed at the onset of the diseases and analyzed in order to identify possible prognostic factors. Nine patients with Multicentric Castleman disease, and 16 with HHV-8-related lymphomas (13 primary effusion lymphomas and 3 solid lymphomas), were diagnosed and treated out of 327 HIV-related non-Hodgkin's lymphomas. Four patients with Multicentric Castleman disease received only antiretroviral drugs; 5 HAART plus oral etoposide. Nine patients with primary effusion lymphoma were treated with a CHOP-like regimen (Cyclophosphamide, Prednisone anthracyclines, Vinca alkaloids, Bleomycin, Etoposide) and HAART; 1 with etoposide and HAART, 1 with HAART alone. The patients with solid lymphoma underwent CHOP-like chemotherapy. Patients with Multicentric Castleman disease showed lower median values of HHV-8 viral load and longer overall survival compared with HHV-8-related lymphomas. Patients with viral load of HHV-8, >40,000 cp/ml had a significant shorter overall survival. In the univariate analysis, HHV-8-related lymphoma, HHV-8 viral load >40,000 cp/ml and performance status >2 were associated with an increased risk of death. Multivariate analysis confirmed the diagnosis of lymphoma as an independent predictor of shorter survival.

Recent thymic emigrants in lymphoma patients with and without human immunodeficiency virus infection candidates for autologous peripheral stem cell transplantation

Signal joint T cell receptor excision circles (sjTRECs) have been reported as a clinical marker to measure the potential for recovery of the immune system after immunosuppressive treatments. The aim of this study was to investigate the thymic regenerative potential in 55 human immunodeficiency virus (HIV)-1 infected (HIV(+)) and non-infected (HIV(-)) lymphoma patients, candidates for autologous stem cell transplantation (ASCT). Moreover, the possible associations between sjTRECs and other immunological and clinical parameters were examined. SjTRECs levels in peripheral blood mononuclear cells (PBMCs) were quantified by real-time polymerase chain reaction and T lymphocyte subsets were analysed by flow cytometry. Our data showed that sjTRECs were reduced in lymphoma patients compared to healthy controls, although a weak significant association between low sjTRECs levels and increasing age was maintained [odds ratio (OR) = 4.00; 95% confidence interval (CI) 1.09-17.17]. We found that different chemotherapeutic treatments seem to induce similar effects on the thymic reservoir, independently from their intensity (type and number of cycles of previous chemotherapy). Results from multivariate models including adjustment for patients' sex, type of lymphoma and type of chemotherapy showed that thymic output was independent from HIV infection (OR, 0.95; 95% CI 0.20-4.48). SjTRECs levels correlated with naive T cell subsets in overall lymphoma patients and after stratification by HIV infection (r > 0.37). HIV replication should be maximally suppressed to properly evaluate thymic output by sjTREC markers. Our results suggested that de novo T cell generation is maintained partially in pretreated recurrent lymphoma patients, candidates for ASCT, and could contribute to restore the immune function after transplantation.

Joint Nordic prospective study on human herpesvirus 8 and multiple myeloma risk

An association between human herpesvirus 8 (HHV8) and multiple myeloma (MM) has been reported, though most studies have not confirmed such association. To follow-up on a previous prospective seroepidemiological study, where HHV8 tended to associate with MM risk, we linked five large serum banks in the Nordic countries with the Nordic cancer registries and 329 prospectively occurring cases of MM were identified, together with 1631 control subjects matched by age and gender. The HHV8 seroprevalences among cases and controls were similar (12 and 15%, respectively) and HHV8 seropositivity did not associate with the risk of MM, neither when considering positivity for lytic antibodies (relative risk (RR)=0.8, 95% confidence interval (CI)=0.5–1.1) nor for latent antibodies (RR=0.6, 95% CI=0.1–2.7). Similar risks were seen when analysis was restricted to case–control sets with at least 2 years lag before diagnosis (RR=0.8, 95% CI=0.5–1.2 and RR=0.9, 95% CI=0.1–4.2). In conclusion, the data indicate that HHV8 infection is not associated with MM.

Laboratory diagnosis of human herpesvirus 8 infection in humans

Human herpesvirus 8 (HHV-8) is causally associated with Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman's disease. Serological and molecular biology assays are used to investigate the biology of this virus in different populations and diseases. Serological assays are mainly used to study the prevalence of the viral infection and to predict the diagnosis of Kaposi's sarcoma and other HHV-8-associated cancers. The appearance of antibodies against lytic antigens precedes the appearance of antibodies against latent antigens, probably explaining the lower sensitivity of assays based on latent HHV-8 antigens. The lack of international reference serum panels is presently the major bottleneck for further progress in the field of HHV-8 serology. Molecular biological assays are an absolute requirement for both the diagnosis and the follow-up of HHV-8 infection. Qualitative methods have been particularly useful to elucidate the mode of transmission and the causal association between HHV-8 and HHV-8-associated diseases. Quantitative methods have become an essential tool to monitor the progression of the infection and the effects of antiviral therapies. This review analyzes the performance of the different serological and molecular biological assays available at present. The main conclusion is that more research is needed to define the most useful laboratory tests for the diagnosis of HHV-8 infection and to establish the clinical role of such tests.

Viral load of human herpesvirus 8 in peripheral blood of human immunodeficiency virus-infected patients with Kaposi's sarcoma

Viral load is an important marker of activity of viral diseases for a number of viruses. We wished to evaluate whether the viral load of human herpesvirus 8 (HHV-8) in peripheral blood was a consistent feature of Kaposi's sarcoma (KS) patients and whether the viral load correlated with human immunodeficiency virus (HIV) RNA levels, CD4 counts, and/or the HHV-8 seroreactivity. Fifty-four consecutive plasma samples from 14 patients with KS were evaluated for HHV-8 viral load by quantitative real-time PCR. Samples were analyzed at the start of highly active antiretroviral therapy (HAART) and at different intervals during treatments. The median HHV-8 DNA load before HAART treatment was 8,998 (ranging from 170 to 40,100) copies/ml and 12,270 (ranging from 40 to 142,575) copies/ml during HAART. There were both increasing and decreasing trends. There was an association between HHV-8 DNA and HIV RNA viral loads (odds ratio [OR] = 5.40; 95% confidence interval [95% CI], 1.54 to 18.98) and between HHV-8 viral load and CD4 cell counts (OR = 7.24; 95% CI, 1.30 to 40.35). High HHV-8 viral load was also correlated with the titers of antibodies to the lytic HHV-8 antigen detected with immunofluorescence (P < 0.01), but not with antibodies to the latent HHV-8 antigen. In conclusion, we found that HHV-8 viremia in KS is associated with HIV viral load, CD4 cell counts, and lytic HHV-8 serological reactivity. HHV-8 viral load monitored by real time PCR might be useful for determination HHV-8 viral load during the follow-up of KS patients.

Lymphocyte subsets and viral load in patients with HIV-associated non-Hodgkin's lymphoma treated with anti-CD20 monoclonal antibody and chemotherapy

The anti-CD20 monoclonal antibody Rituximab is a novel antitumor agent used in association with chemotherapy (CT) for the treatment of high-grade/intermediate non-Hodgkin's lymphomas (NHL) in HIV-negative populations. This therapeutic combination is currently also being explored in HIV-positive patients with NHL (HIV-NHL). The objective of our study was to determine CD4 and CD8T cell counts, HIV plasma viremia and proviral load in patients with CD20-positive HIV-NHL treated with Rituximab plus CT and highly active antiretroviral therapy (HAART). We studied eight patients with HIV-NHL treated by anti-CD20 and CT before, after three, and after six cycles of therapy; CD4, CD8 and CD19 lymphocyte subsets were measured by monoclonal antibodies and flow cytometry. HIV plasma viremia was determined by the b-DNA assay, and proviral load by a quantitative competitive PCR. CD4T cell counts remained stable after three cycles of therapy, while a significant reduction of this subset was present at the end of therapy. HIV plasma viremia was significantly reduced after the third cycle, but returned to pretreatment levels at the end of therapy; we also observed individual fluctuations of proviral load during therapy, this marker being increased in two out of three patients at the end of therapy. These observations suggest that Rituximab plus CT accelerated the rate of CD4 depletion and of HIV replication in the peripheral blood of HIV-NHL patients and that HAART may be able to delay these effects.

A prospective seroepidemiological study of human herpesvirus-8 infection and the risk of multiple myeloma

Presence of the Human Herpesvirus 8 (HHV8) genome has been reported in the bone marrow of multiple myeloma (MM) patients. So far, serological studies of HHV8 and MM have been inconsistent but have not included prospective epidemiological studies. We evaluated whether HHV8 infection is associated with increased risk for MM in a prospective population-based study of 39 000 Finnish subjects who donated serum samples in the period 1968-72. Serum samples from 47 subjects who developed MM during a 23-year follow-up and 224 age, area of residence and sex-matched subjects who remained healthy over a similar follow-up period were evaluated for HHV8 antibodies at enrollment, as assayed both with an immunofluorescence assay (IFA) for lytic and latent HHV8 antigens and by Western blot (WB) with three recombinant HHV8 proteins (ORFs 65, 73 and K8.1A). HHV8 seropositivity for at least one HHV8 protein on WB was found in 7% of the Finnish population and was not associated with the risk of developing MM (Relative Risk (RR) = 0.89, Confidence Interval (CI): 0.25-3.25). HHV8 seropositivity for lytic and latent antigens in the IFA was found in 16% and 0.4% of the Finnish population and tended to associate with risk of MM (RR = 2.02, CI: 0.94-4.33 and RR = 10.00, CI: 0.91-110.29, respectively). In conclusion, no statistically significant evidence for an association between HHV8 infection and the risk of future MM was found.

Seropositivity to human herpesvirus 8 in relation to sexual history and risk of sexually transmitted infections among women

The mode of transmission of human herpesvirus 8 (HHV8) was investigated in two seroepidemiological studies of Swedish women who completed a questionnaire about sexual behavior. Seropositivity for HHV8 antibodies, measured using an indirect immunofluorescence assay, was linked to a high number (>10) of sexual partners (P < 0.004). It also correlated strongly with a history of other sexually transmitted diseases (STD; P < 0.0001), in particular with a history of Chlamydia trachomatis infection and condyloma acuminata. There was appreciable HHV8 seropositivity already among virginal or monogamous women (9%). In summary, HHV8 transmission to women in Sweden may occur nonsexually. When sexual transmission occurs, it appears to be associated with high risk-taking sexual behavior.

Two Field Isolates of Tomato Spotted Wilt Tospovirus Overcome the Hypersensitive Response of a Pepper (Capsicum annuum) Hybrid with Resistance Introgressed from C. chinense PI152225

The hypersensitive response to tomato spotted wilt tospovirus (TSWV) present in Capsicum chinense PI152225 (1) was introgressed into C. annuum cultivars. During the summer of 1998, a hybrid with good agronomic performance was grown in glasshouses in Albenga, Liguzia Region of northwestern Italy, an area where infection by TSWV in pepper has been severe since 1992. In August, observations of different susceptible cultivars revealed that >50% of plants had TSWV-like symptoms, whereas the resistant hybrid remained healthy, except for two plants that showed virus-like symptoms on apical leaves and fruits. From the infected plants, tospoviruses (coded P164/6 and P166) were transmitted by sap-inoculation to Nicotiana benthamiana. Triple-antibody sandwich enzyme-linked immunosorbent assay with a panel of monoclonal antibodies against the TSWV nucleocapsid, but with different reactivity to the related species groundnut ringspot (GRSV) and tomato chlorotic spot (TCSV) viruses, indicated the isolates were TSWV. The host ranges of the isolates were wide and typical of normal TSWV isolates. Thus, they incited typical symptoms in all 50 TSWV-susceptible C. annuum cv. Quadrato d'Asti plants. However, isolate P164/6 also systemically infected 12 of 27 C. chinense PI152225 and 14 of 19 C. chinense PI159236 plants. These accessions are normally resistant to TSWV (1). Isolate P166 systemically infected 7 of 17 C. chinense PI152225 and 6 of 11 C. chinense PI159236 plants. Systemically infected plants showed severe necrosis, and some plants died. Other plants showed only necrotic local lesions. The response by C. chinense differed from that caused by typical TSWV, which causes only local lesions, and from both GRSV and TCSV, which cause mosaic but no necrosis in 100% of plants. The two new TSWV isolates were tested for transmission using a local population of Frankliniella occidentalis in a leaf disk assay with susceptible C. annuum. Transmission rates were high: 93.7% (63 thrips) for isolate P164/6 and 89.9% (49 thrips) for P166. Thus, the fitness of the two TSWV resistance-breaking isolates (a wide experimental host range and high transmission rates by the natural vector) was as high as that of typical TSWV. The absence of systemic infection in some C. chinense PI152225 and PI159236 plants that are resistant to typical TSWV suggests the possibility of selecting plants resistant to these pathotypes. This is the first report of field tospovirus isolates typed as TSWV (according to the current taxonomy based on nucleocapsid serology) overcoming the hypersensitive response of C. chinense PI152225 and PI159236, an ability previously found only in closely related viruses: TCSV and GRSV (2). Other TSWV-like isolates systemic on C. chinense were not typed further (3,4). References: (1) L. L. Black et al. Plant Dis. 75:863, 1991. (2) L. S. Boiteux and A. C. DeAvila. Euphytica 75:139, 1994. (3) H. A. Hobbs et al. Plant Dis. 78:1220, 1994. (4) B. Moury et al. Euphytica 94:45, 1997.

Human serum antibodies to a major defined epitope of human herpesvirus 8 small viral capsid antigen

The major antibody-reactive epitope of the small viral capsid antigen (sVCA) of human herpesvirus 8 (HHV-8) was defined by use of overlapping peptides. Strong IgG reactivity was found among approximately 50% of 44 human immunodeficiency virus-positive or -negative patients with Kaposi's sarcoma and 13 subjects who were seropositive by immunofluorescence assay (IFA) for the latent HHV-8 nuclear antigen. Only 1 of 106 subjects seronegative for both lytic and latent HHV-8 antigens and 10 of 81 subjects IFA-seropositive only for the lytic HHV-8 antigen had strong IgG reactivity to this epitope. Among 534 healthy Swedish women, only 1.3% were strongly seropositive. Comparison of the peptide-based and purified sVCA protein-based ELISAs found 55% sensitivity and 98% specificity. However, only 1 of 452 serum samples from healthy women was positive in both tests. In conclusion, the defined sVCA epitope was a specific, but not very sensitive, serologic marker of active HHV-8 infection. Such infection appears to be rare among Swedish women, even with sexual risk-taking behavior.

High CD40 membrane expression in AIDS-related lymphoma B cell lines is associated with the CD45RA+, CD45RO+, CD95+ phenotype and high levels of its soluble form in culture supernatants

CD40 is a membrane glycoprotein expressed on normal and neoplastic B lymphocytes. Stimulation through CD40 regulates important cellular functions, but the effects depend on its membrane density. While extensive studies have characterized CD40 in non-Hodgkin lymphomas of immunocompetent individuals, little is known on the characteristics of this molecule in lymphomas arising in immunocompromised hosts. The aim of this study was to characterize the pattern of CD40 expression in an in vitro model constituted by AIDS small non-cleaved lymphoma (SNCCL) cell lines. The analysis of CD45 isoforms, a group of molecules alternatively spliced during B cell differentiation, has been chosen to correlate this process to the number of CD40 molecules per cell in these cell lines. Since Apo 1/Fas expression is upregulated on B lymphocytes after CD40 ligation and this expression is functionally relevant, we wanted to know whether a different CD40 pattern in AIDS-SNCCL cell lines could influence CD95 expression. We have shown that 3 of these cell lines (PA 682, Es III, and HBL-2) have high membrane CD40 expression (> 100,000 molecules/cell); they release large amounts of soluble CD40 (sCD40) in culture supernatants (>500 pg/ml), are CD45RA/RO double labelled, and express the Apo 1/Fas (CD95) antigen. On the contrary, low CD40 membrane antigen cell lines (BRGIgA, HBL-2, NC 71, AS 283A, and LAM C3+, < 50,000 molecules/cell) release low amounts of sCD40 (<300 pg/ml), are CD45RA+ but CD45RO-, and do not express CD95. EBV has no role in CD40 and CD45 isoform behaviour, because EBV superinfection of the EBV negative, low membrane CD40 HBL-2 cell line does not modify CD40 membrane expression, sCD40 production, or CD45 isoform and CD95 expression. Our data suggest that membrane CD40 in AIDS-SNCCL cell lines might be a key element in the regulation of their pathophysiology by influencing the expression of CD45 isoforms and of CD95, and by the release of its soluble form.

Antibody responses to defined epitopes in the Epstein-Barr virus BZLF1-encoded transactivator protein among human immunodeficiency virus-infected patients

The Epstein-Barr virus BZLF1-encoded replication activator (ZEBRA) is a key mediator of reactivation from latency to the viral productive cycle. In the present study, the serum antibody responses against three defined ZEBRA epitopes (designated ZEBRA-1, -19, and -22) were determined for 50 human immunodeficiency virus (HIV)-seropositive patients and 100 matched healthy control subjects. The anti-ZEBRA responses were more commonly found among HIV-seropositive patients than among healthy controls for all the three ZEBRA epitopes tested (P < 0.0003, P < 0.003, and P < 0.001, respectively). Comparison of ZEBRA antibody levels with the degree of immunodeficiency (CD4 cell counts), CDC grouping, and HIV p24 antigen positivity showed little association, suggesting that induction of ZEBRA antibodies is an early event after HIV infection.

The disease associations of the antibody response against the Epstein-Barr virus transactivator protein ZEBRA can be separated into different epitopes

The BamHI-Z-encoded Epstein-Barr virus (EBV) replication activator (ZEBRA) is a key mediator of the switch from latency to productive cycle in EBV virus. Antibodies against ZEBRA are a marker of EBV reactivation and are regularly found among patients with infectious mononucleosis (IM) or nasopharyngeal carcinoma (NPC), but are only rarely found among healthy EBV-seropositive donors. In order to define the serologically reactive epitopes in the ZEBRA protein, we synthesized a set of overlapping peptides and tested them for reactivity with serum samples from EBV-seronegative persons, patients with NPC, IM, chronic fatigue syndrome, lymphoma or from healthy donors. Three major EBV-specific epitopes were found. These epitopes were further defined and optimized using substitution or truncation analogues of the peptides. Reactivity with epitope number 22 was found in 63% of NPC patients' sera, with < 2% of healthy donors' sera being positive. Serological reactivity with epitope number 19 was associated with IM (57% positive, 5% healthy donors positive). Serum antibodies against epitope 1 were found among healthy donors, but were significantly elevated among patients with NPC, IM or lymphomas. In conclusion, different serologically reactive epitopes in the ZEBRA protein associate with different EBV-associated diseases.