Effect of tongue position on masseter and temporalis electromyographic activity during swallowing and maximal voluntary clenching: a cross-sectional study.

The purpose of this study was to measure and compare the tonic electromyographic (EMG) activity of the temporalis and masseter muscles following placement of the tongue either on the palate or in the floor of the mouth during swallowing and maximal voluntary clenching (MVC). Thirty healthy dental students with natural dentition and bilateral molar support, between the ages of 18 and 22, with no prior history of oro-facial injury, or current or past pain in the jaw, mouth or tongue participated in the study. Tonic masseter and temporalis EMG activities were recorded using surface electrodes. Subjects were instructed to passively place the tongue either on the anterior hard palate or in the floor of the mouth during swallowing and MVC. At each tongue position, the resulting EMG was recorded. During swallowing, no significant difference in EMG activity was found either for the masseter (P-value = 0.1592) or the temporalis (P-value = 0.0546) muscles, regardless of the tongue position. During MVC, there was a statistically significant difference for both the masseter (P-value = 0.0016) and the temporalis (P-value = 0.0277) muscles with lower levels recorded with the tongue in the floor of the mouth. This study found that in normal, pain-free subjects, placing the tongue in the floor of the mouth significantly reduces masticatory muscle activity during MVC. Thus, it may be considered as a possible therapeutic option to decrease masticatory muscle activity; however, further research is needed in patients with oro-facial pain.

Bite force measurements with hard and soft bite surfaces.

Bite force has been measured by different methods and over a wide variety of designs. In several instruments, the fact that bite surface has been manufactured with stiff materials might interfere in obtaining reliable data, by a more prompt activation of inhibitory reflex mechanisms. The purpose of this study was to compare the maximum voluntary bite force measured by a digital occlusal force gauge (GM10 Nagano Keiki, Japan) between different opponent teeth, employing semi-hard or soft bite surfaces. A sample of 34 young adults with complete natural dentition was studied. The original semi-hard bite surface was exchanged by a soft one, made of leather and rubber. Maximum voluntary bite force recordings were made for each tooth group and for both bite surfaces. Statistical analyses (Student's t-test) revealed significant differences, with higher scores while using the soft surface across sexes and tooth groups (P < 0·05). Differential activation of periodontal mechanoreceptors of a specific tooth group is mainly conditioned by the hardness of the bite surface; a soft surface induces greater activation of elevator musculature, while a hard one induces inhibition more promptly. Thus, soft bite surfaces are recommended for higher reliability in maximum voluntary bite force recordings.

The effect of tongue position and resulting vertical dimension on masticatory muscle activity. A cross-sectional study.

The purpose of this study was to: (a) compare the tonic electromyographic (EMG) activity of the temporalis and masseter muscles between two tongue positions, (b) compare the vertical dimension (VD) resulting from each tongue position and (c) determine the influence of the VD on the tonic EMG activity for each tongue position. Thirty-three healthy dental students with natural dentition and bilateral molar support, between the ages of 18 and 22 years, with no prior history of oro-facial injury, or current or past pain in the jaw, mouth, or tongue participated in the study. Tonic masseteric and temporalis EMG activities were recorded using surface electrodes. Subjects were instructed to passively place the tongue either on the anterior hard palate or in the floor of the mouth. At each tongue position, the resulting EMG and VD were recorded. No significant difference in EMG activity was found for either the masseter (P-value = 0·5376) or temporalis muscle (P-value = 0·7410), between the two tongue positions. However, there was a significant difference in the VD resulting from the two different tongue positions, being greater with the tongue placed in the floor of the mouth. There was no statistically significant correlation between VD and EMG activity for both tongue positions. In spite of the lack of difference in the effect of both tongue positions on the masseteric and temporalis EMG activity, an increment of the VD was registered for the floor of mouth-tongue position. However, VD was not correlated with EMG activity for both tongue positions.

Performance of D-amino acid oxidase in presence of ionic liquids.

The activity and stability of free and immobilized D-amino acid oxidase (DAAO, EC 1.4.3.3) from Trigonopsis variabilis CBS 4095 in different water-soluble and water-insoluble ionic liquids (ILs) as well as in organic solvents were studied for comparison. The most promising ILs ([BMIM][BF(4)] and [MMIM][MMPO(4)]) were investigated in detail. The kinetic parameters (v(max) = 187 nkat/g dry weight, K(M) = 1.38 mM) with D-phenylalanine as substrate were calculated in 40% [BMIM][BF(4)]. Bioconversions of D/L-phenylalanine in 40% [BMIM][BF(4)] and 20% [MMIM][MMPO(4)] on a 3 ml scale using immobilized DAAO were performed by addition of free catalase from Micrococcus lysodeikticus. After total conversion of substrate in presence of 20% [MMIM][MMPO(4)] the residual activity of the immobilized DAAO was 79% and 100% of the free catalase.

Epidemiology of brain lymphoma among people with or without acquired immunodeficiency syndrome. AIDS/Cancer Study Group.

BACKGROUND: In recent years, brain lymphoma incidence has dramatically increased, presumably because of elevated risk of brain lymphoma among persons with acquired immunodeficiency syndrome (AIDS). PURPOSE: The objective of this study was to estimate independent incidence and survival rates of brain lymphoma among persons with or without AIDS and to understand the epidemiologic features of this cancer. METHODS: We linked AIDS and cancer registry reports at nine state and local health departments and compared the demographics, histology, and survival of brain lymphoma cases among persons with or without AIDS. The data were limited to people under 70 years of age. We calculated the incidence of brain lymphoma among persons with AIDS and compared observed cases with those expected. The differences were statistically analyzed using the Poisson test. Epidemiologic features of brain lymphoma in persons with or without AIDS were compared using the chi-squared test, the Student's t test, and the chi-squared test for linear trend. The logrank test was used to compare survival rates estimated by the Kaplan-Meier technique. All P values were two-sided. RESULTS: We matched 50,989 AIDS registry reports to 859,398 cancer registry reports (data from 1981 to 1990) and found 431 people with both AIDS and brain lymphoma. Among people with AIDS, those developing brain lymphoma versus those without brain lymphoma were more likely to be white (70% versus 59%; P < .001) and had homosexuality as their only human immunodeficiency virus risk factor (75% versus 64%; P < .001). Of the 431 patients, 223 developed brain lymphomas during 47,465 person-years of observation after diagnosis of AIDS. The absolute incidence rate of brain lymphoma among persons with AIDS was 4.7/1000 person-years (95% confidence interval = 4.1-5.3/1000 person-years), 3600-fold higher than the base-line rate in the general population. From 1980 through 1989, overall counts of brain lymphoma increased ninefold. Most of this increase was derived from persons with AIDS, but a substantial increase also occurred among persons without AIDS (0.04/100,000 in 1982 to 0.28/100,000 in 1989) (chi-squared test for trend; P < .05). The median survival was shortest for persons with AIDS and brain lymphoma (2 months), was intermediate for persons with brain lymphoma without AIDS (5-7 months), and was longest for persons with AIDS without brain lymphoma (14 months) (P < .05 for all comparisons). CONCLUSIONS: This analysis distinguishes the separate epidemiologies of brain lymphoma incidence among persons with or without AIDS and shows brain lymphoma incidence among persons with AIDS to be several thousand-fold higher than that in the general population. The study documents the overwhelming effect of AIDS-associated brain lymphoma on the overall rate in the general population and demonstrates a significantly rising trend, although of a lesser magnitude, among persons without AIDS. IMPLICATIONS: This study emphasizes a greater need to bring health care resources to this burgeoning epidemic.

Effect of human T-lymphotropic virus type I infection on non-Hodgkin's lymphoma incidence.

BACKGROUND: We previously reported from a case-control analysis that T-cell non-Hodgkin's lymphoma (NHL) was strongly associated with human T-lymphotropic virus type I (HTLV-I) infection in Jamaica and Trinidad and that the relative risk for HTLV-I infection was very high in younger patients. PURPOSE: The objective of this study was to estimate the age-specific incidence rates of NHL among HTLV-I-infected and HTLV-I-uninfected adults in Jamaica and Trinidad. METHODS: Population rates of HTLV-I infection were calculated from available census reports and serosurvey data. Incidence rates for NHL were calculated from all incident cases in Jamaica during 1984-1987 (n = 135) and from all incident cases in Trinidad during 1986-1990 (n = 117). Using biopsy material, we determined whether the immunophenotype of the tumor cells was T cell, B cell, or other. NHL incidence rates were computed according to HTLV-I status, age, sex, and tumor phenotype for each country separately and for both countries combined by weighting to the relative population size of each country. RESULTS: The age-standardized NHL incidence rate (mean +/- SE) in Jamaica was 1.9 +/- 0.2 per 100,000 person-years (PY). In Trinidad, the rate was 2.9 +/- 0.4 per 100,000 PY. Overall, the incidence of NHL increased with age and was higher in males than in females. In the HTLV-I-infected population, the incidence of NHL was inversely related to age, and age-specific rates were higher in males than in females. The NHL incidence in those estimated to have acquired HTLV-I infection in childhood, however, showed no sex difference, and one in 1300 such carriers (95% confidence interval: one in 1100 to one in 1600) per annum were estimated to be at such risk. For T-cell NHL, as proxy for adult T-cell lymphoma/leukemia, incidence was highest in those patients infected with HTLV-I early in life (perinatally or via breast milk), with high, sustained risk from early adulthood in both sexes. CONCLUSIONS: While overall NHL incidence rates reveal that HTLV-I endemicity does not impose an exaggerated lymphoma burden on these populations, the risk for lymphoma among carriers who acquire infection early in life is dramatic and is consistent with the hypothesis that virus exposure early in life is most important for lymphoma-genesis. IMPLICATIONS: Studies of HTLV-I carriers known to be infected in childhood may provide insight into markers intermediate in the lympho-magnetic process. Strategies to disrupt early-life transmission of HTLV-I, notably mother-infant transmission, may be critical in reducing the burden of lymphoreticular disease in these populations.

Human leukocyte antigen class II alleles associated with human T-cell lymphotropic virus type I infection and adult T-cell leukemia/lymphoma in a Black population.

BACKGROUND: Human T-cell lymphotropic virus type I (HTLV-I) is linked to adult T-cell leukemia/lymphoma (ATL) and HTLV-I-associated myelopathy (HAM; also known as tropical spastic paraparesis [TSP]), a chronic neurodegenerative disorder. Worldwide, several million HTLV-I carriers are at risk for disease, with an estimated lifetime cumulative risk of 1%-5%. However, the determinants of disease progression are relatively unknown. We studied human leukocyte antigens (HLA class II) that have been implicated in the pathogenesis of HTLV-I-related diseases. METHODS: We analyzed HLA class II alleles among asymptomatic HTLV-I carriers (n = 45), patients with ATL (n = 49) or HAM/TSP (n = 54), and HTLV-I seronegative control subjects (n = 51). All participants were of African descent and were enrolled in epidemiologic studies conducted at the University of the West Indies, Kingston, Jamaica. We used standard microlymphocytotoxicity assays for HLA antigen serotyping and polymerase chain reaction-based methods to examine HLA class II DRB1 and DQB1 alleles. RESULTS: Two antigens determined by serotyping, DR15 and DQ1, occurred at significantly increased frequency among HTLV-I carriers compared with seronegative control subjects (42% versus 22% for DR15 [odds ratio [OR] = 2.7; 95% confidence interval [CI] = 1.0-7.2] and 78% versus 53% for DQ1 [OR = 3.1; 95% CI = 1.2-8.5]). Asymptomatic carriers were shown to have an HLA class II allele distribution similar to that of patients with ATL, and the frequencies of the alleles DRB1*1501, DRB1*1101, and DQB1*0602 were significantly greater in patients with ATL and asymptomatic carriers than in patients with HAM/TSP. In addition, haplotypes DRB1*1101-DQB1*0301 and DRB1*1501-DQB1*0602 were significantly increased among patients with ATL compared with patients with HAM/TSP. CONCLUSIONS: These data suggest that host genetic background is an important factor in determining whether HTLV-I carriers develop either ATL or HAM/TSP.

Blood levels of organochlorines before and after chemotherapy among non-Hodgkin's lymphoma patients.

Several small studies suggest a link between environmental exposure to organochlorine compounds and risk of non Hodgkin's lymphoma (NHL). Because NHL is uncommon, studies of the topic often use a population-based case-control design, in which cases generally are enrolled after treatment has begun. If chemotherapy affects blood levels of organochlorines, exposure will be misclassified and findings distorted. To determine whether chemotherapy alters serum levels of organochlorines in NHL cases, we compared serum samples before and after treatment in 22 cases diagnosed with NHL between March 1994 and August 1995 and enrolled in a clinical trial at the United States National Cancer Institute's Clinical Center. The time difference between pretreatment and posttreatment samples ranged from 15 to 27 months with an average of 20 months. Laboratory analyses were conducted in blinded pretreatment and posttreatment pairs of the subjects. Pretreatment and posttreatment organochlorine serum levels were compared using Pearson correlation coefficient (r) and paired t test. The pretreatment and posttreatment serum levels were highly correlated for 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and polychlorinated biphenyls (PCBs) PCB-138, PCB-153, PCB-156, and total PCBs (ranging from 0.78 to 0.93). Serum levels of all of these organochlorines significantly decreased between initiation and completion of chemotherapy, 25% for total PCB (P = 0.0044), 28% for DDE (P = 0.0014), 25% for PCB-138 (P = 0.0053), 27% for PCB-153 (P = 0.0031), and 29% for PCB-156 (P = 0.045). Neither weight change nor lipid change was correlated with changes in chemical levels. There was no association between the length of time between blood draws and changes in chemical levels. Our data raise the possibility that lymphoma treatment depresses serum organochlorine levels.

Distribution of human leukocyte antigens in a population of black patients with human T-cell lymphotrophic virus type I-associated adult T-cell leukemia/lymphoma.

Human leukocyte antigens (HLAs) play an important role in regulating the immune response to infectious agents and determinants of malignant transformation. We compared the HLA frequencies of 25 black patients with adult T-cell leukemia/lymphoma (ATL) referred to the National Cancer Institute for therapy with a racially similar, asymptomatic control population of human T-cell lymphotrophic virus, type I (HTLV-I)-seropositive individuals (n = 45). Serological typing was performed for MHC class I and II antigens. Antigen frequencies were calculated, and corresponding gene frequencies were estimated using the maximum likelihood method. Comparisons between the ATL and control group were made with chi 2 or Fisher's exact test. Three antigens (A36, B18, and DR53) were found to have a higher frequency in the ATL patients than in the controls (uncorrected two-tailed P < 0.05). The gene frequencies for these antigens also were statistically significant in the uncorrected analysis. However, only A36 approached statistical significance after correction of the P value for multiple comparisons (P = 0.08). The results of this pilot study indicate that black patients with ATL may have increased frequencies of certain class I HLA when compared with a racially similar HTLV-I-positive reference population. This suggests that either these antigens may represent markers for a population at greater risk of developing ATL once infected with HTLV-I or that they were acquired at some point in the process of malignant transformation or progression from the carrier state to onset of ATL. These antigens should be targeted in larger studies to confirm or refute these findings.

Differential patterns of serum biomarkers of immune activation in human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis, and adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATL) and human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) are associated with differing patterns of immune dysfunction. Biomarkers of immune activation may correlate with perturbations of immune function associated with these diseases. We conducted a pilot cross-sectional study to assess four candidate biomarkers of immune activation. beta 2-microglobulin, neopterin, tryptophan, and kynurenine levels were assayed in stored sera from asymptomatic, human T-cell leukemia virus type I (HTL V-I)-seronegative (HTLV-I-) and HTLV-I-seropositive (HTLV-I+) individuals, and ATL and HAM/TSP patients previously enrolled in seroepidemiological studies in Jamaica. Mean levels of beta 2-microglobulin, neopterin, and kynurenine were significantly elevated among ATL patients compared to the other study groups. Mean tryptophan levels were significantly lower among ATL and HAM/TSP patients than HTLV-I- and HTLV-I+ groups. No significant differences in biomarkers were found between the HTLV-I- and HTLV-I+ groups. Among HAM/TSP patients, a significant association was found between elevated neopterin levels and symptoms of less than 4 years duration. In Cox proportional hazards regression modeling, neopterin and tryptophan were found to be independent predictors of survival among ATL patients. This study demonstrates a differential pattern of biomarkers of immune activation among ATL and HAM/TSP patients compared to HTLV-I- and HTLV-I+ individuals. Neopterin and tryptophan may be useful clinical indicators of disease severity and prognosis among HAM/TSP and ATL patients.

Cervical intraepithelial neoplasia is not associated with elevated serum neopterin levels.

Neopterin, a marker of cellular immune activation, was elevated in patients who had cervical cancer in previous studies. To examine neopterin in the presence of precursors to cervical cancer (i.e., cervical intraepithelial neoplasia) we measured serum levels in 185 colposcopy patients in Jamaica, a country with high cervical cancer incidence, and in 72 age-matched Jamaican women selected from a large population-based sample. We also measured serum levels of beta-2-microglobulin, another commonly used marker of immune activation. Neopterin and beta-2-microglobulin levels were not elevated in colposcopy patients; neither were they related to severity of cervical neoplasia. In multivariable analysis, neither adjustments for detection of cervical human papillomavirus DNA by PCR nor detection of antibodies to human T-cell lymphotropic virus type I (a retrovirus endemic to Jamaica) altered our findings. The absence of a serologically detectable increase in cellular immune activation linked to cervical intraepithelial neoplasia suggests that the immunological response to cervical intraepithelial neoplasia does not involve substantial systemic cellular immune activation.

HTLV-I specific IFN-gamma+ CD8+ lymphocytes correlate with the proviral load in peripheral blood of infected individuals.

Human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is an inflammatory neurological disease caused by HTLV-I infection. It has been shown that HAM/TSP patients have high proviral loads and an extraordinarily high frequency of circulating CD8 + cytotoxic T lymphocytes specific for HTLV-I in their peripheral blood when compared to asymptomatic HTLV-I carriers (AC). We have previously described an intracellular cytokine detection assay, in which interferon-gamma (IFN-gamma) + CD8 + lymphocytes are specific for HTLV-I in infected individuals. Here, we have established a competitive polymerase chain reaction assay to measure the proviral load of patients and investigate a potential relationship between proviral load and virus-specific CD8 + lymphocytes. Genomic DNA was extracted from peripheral blood lymphocytes (PBL) from eight HAM/TSP patients and seven AC for the measurement of HTLV-I measuring proviral loads. The same PBL were analyzed for intracellular IFN-gamma expression by flow cytometry. In the HAM/TSP patients and AC, the average proviral loads were 34,482 and 9784 copy/microg DNA (P = 0.021), and the average of IFN-gamma + CD8 + lymphocytes in total PBL were 1.47 and 0.08% (P = 0.001), respectively. It was confirmed that HAM/TSP patients have both high proviral loads and increased HTLV-I-specific CD8 + lymphocytes. Furthermore, we found a positive correlation between both factors in the patients with HAM/TSP (P = 0.044) but not in the AC (P = 0.508). These findings suggest that the high number of HTLV-I-specific lymphocytes may result from the increased proviral load in HAM/TSP patients.

Fast isolation of recombinant baculovirus by antibody screening.

The use of a rapid and efficient scheme for the detection and purification of recombinant baculoviruses is described. The method is based on the detection of foreign proteins in cellular lysates of baculovirus-infected insect cells by antibody screening. The recombinant virus is purified by repeated serial dilutions. The method allows the identification and purification of recombinant viruses within two to three weeks.

Viral-specific humoral immune responses following transfusion-related transmission of human T cell lymphotropic virus type-I infection.

The immunoglobulin (Ig) isotypes of antibodies to specific proteins of the human T cell lymphotropic virus type I (HTLV-I) were determined by Western blot analysis of serial specimens from six individuals who experienced HTLV-I seroconversion following blood transfusion; five remained asymptomatic carriers, while one developed HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) 32 weeks posttransfusion. Analysis of Ig isotypes demonstrated that while IgM was the most frequent early response to gag (p19, p24) and env (r21e) proteins within the first 3 months following transfusion, IgG and IgA responses could also be detected within this period. HTLV-I-specific antibody responses plateaued in all Ig isotypes, including IgM, within the next 4- to 6-month period following transfusion and persisted through the entire study period (> 4 years). Comparison of antibody profiles in Ig isotypes and IgG1 and IgG3 subclass among asymptomatic carriers and one individual who developed HAM/TSP demonstrated no evidence of isotypic prominence or IgG subclass restriction in either group. These results indicate the appearance of HTLV-I-specific IgM that persists even after the primary infection and suggest that such response does not appear to provide an early marker of seroconversion. Further, we found no evidence of isotypic prominence or restriction of the antibody response in recipients who remained asymptomatic compared to one who developed HAM/TSP.

Real-time polymerase chain reaction assay for cell-associated HTLV type I DNA viral load.

We have developed a quantitative real-time PCR assay for HTLV-I DNA. This assay approach uses real-time monitoring of fluorescent signal generation as a consequence of Taq-mediated amplification of specific target sequences to allow real-time kinetic analysis of amplicon production. This kinetic approach yields excellent sensitivity and an extremely broad linear dynamic range, and ensures that quantitation is based on analysis during the exponential phase of amplification, regardless of the input template copy number. The HTLV-I DNA assay has a nominal threshold sensitivity of 10 copy Eq/reaction, although single-copy plasmid template can be detected at frequencies consistent with statistical prediction. The linear dynamic range is in excess of 5 logs. Interassay reproducibility averages 14% (coefficient of variation) for control templates over a range of 10(1) to 10(6) copy Eq/reaction and 25%, based on studies of extraction and analysis of replicate aliquots of PBMC specimens from HTLV-I-infected subjects. The primer/probe combination targets tax sequences conserved across described HTLV-I and HTLV-II isolates. Parallel quantitation in the same samples of an endogenous sequence present at a known copy number per cell allows normalization of results for potential variation in DNA recovery. Availability of this assay should facilitate studies of basic pathogenesis and clinical evaluation of HTLV-I and HTLV-II infection, as well as assessment of therapeutic approaches.

Presence of human T lymphotropic virus types I and II in Ghana, west Africa.

Until recently, HTLV-I was considered to be an Old World virus and HTLV-II was thought to be endemic in the Americas. However, the presence of HTLV-II among Pygmies and other populations of Africa has raised doubts as to whether HTLV-II is primarily a New World virus. The large serosurveys conducted in the urban and rural areas of southern Ghana have identified a 1-2% prevalence for HTLV-I/II. To define the HTLV type, we have used a Western blot assay (HTLV-2.3 blot) that allows simultaneous confirmation and differentiation between HTLVs. Samples (n = 139) were chosen on the basis of previous reactivity with either an enzyme immune assay or r21e-spiked WB results. The WB 2.3 analysis of these specimens identified 55 (40%) to be HTLV positive, 70 (50%) to be HTLV indeterminant, and 14 (10%) to be HTLV negative for HTLV. HTLV seroindeterminant patterns ranged from both gag and env (14 were r21+, p24+, and/or p19+ [all were RIPA negative]) to gag only (21 were p24+/p19+, 16 were p19+, and 7 were p24+), and env only (8 were r21+ and 4 were rgp46+) reactivities. Of the 55 HTLV-positive specimens, 41 were typed as HTLV-I, 9 were HTLV-II, and 5 could not be typed (HTLV-I/II). Of the nine HTLV-II-positive specimens, three were from patients with Burkitt's lymphoma and six were from healthy individuals (two pregnant women) with no obvious risk factors for HTLV-II.(ABSTRACT TRUNCATED AT 250 WORDS)

The prevalence of antibodies to the human T lymphotropic virus (HTLV) in Ghana, West Africa.

We conducted a population-based serosurvey of urban areas and rural regions of southern Ghana, West Africa. Subjects (3763) of all ages were enrolled from 25 city and village sites and in studies of groups of special interest. "Positive" results were difficult to define because of a high frequency of results that were indeterminate on immunoblotting, the current standard for confirmation of HTLV-I. However, polymerase chain reaction results and HTLV type-specific discriminatory tests proved HTLV-I was present in Ghana. No HTLV-2 positivity was observed. By using strict criteria that considered indeterminate results as negative, the overall prevalence was found to be between 1 and 2% in all areas, with no difference by geographic location. Prevalence rose with age and was higher in adult women than men. However, in substudies of selected populations, we found HTLV prevalence among 124 persons with lymphomas and hematological malignancies was not different from that in the general population. Furthermore, the prevalence in prostitutes was similar to that in the general population and in pregnant women. HTLV-I is present in West Africa, but we were unable to associate HTLV-I seropositivity with malignancy or with prostitution.

Comparison of HHV-6 antibody titers in West Africa and the Caribbean.

Human herpesvirus-6 (HHV-6) infection seems to be ubiquitous early in life, but antibody responses vary by geographic area. We compared HHV-6 antibody titer in 123 West African and 122 Caribbean serum samples. A quantitative immunofluorescence assay (IFA) using antigens derived from an HSB-2 cell line was used to test for IgG HHV-6 (GS strain) antibodies. The prevalence of HHV-6 antibodies was high (98%) in both sites. African samples had a significantly higher geometric mean titer (GMT: 697) than did Caribbean samples (GMT: 99). There was no difference between males (GMT: 260) and females (GMT: 270) overall. Children up to and including 9 years old had significantly higher titers (GMT: 483) than did all others (GMT: 237), and female children tended to have higher titers than did male children. In both areas there was a trend towards highest titer at younger age, followed by a decrease in titer during adulthood and middle age, and a secondary rise in titer in the oldest age group. Environmental and host factors may explain these geographic differences in antibody responses between two groups of African origin.

HLA DRB1*DQB1* haplotype in HTLV-I-associated familial infective dermatitis may predict development of HTLV-I-associated myelopathy/tropical spastic paraparesis.

A possible causal association between infective dermatitis and HTLV-I infection was reported in 1990 and confirmed in 1992. We now report familial infective dermatitis (ID) occurring in a 26-year-old mother and her 9-year-old son. The mother was first diagnosed with ID in 1969 at the age of 2 years in the Dermatology Unit at the University Hospital of the West Indies (U.H.W.I.) in Jamaica. The elder of her 2 sons was diagnosed with ID at the age of 3 years, also at U.H.W.I. Both mother and son are HTLV-I-seropositive. A second, younger son, currently age 2 years, is also HTLV-I-seropositive, but without clinical evidence of ID. Major histocompatibility complex (MHC), class II, human leucocyte antigen (HLA) genotyping documented a shared class II haplotype, DRB1*DQB1* (1101-0301), in the mother and her 2 sons. This same haplotype has been described among Japanese patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and has been associated with a possible pathologically heightened immune response to HTLV-I infection. The presence of this haplotype in these familial ID cases with clinical signs of HAM/TSP may have contributed to their risk for development of HAM/TSP. The unaffected, HTLV-I-seropositive younger son requires close clinical follow-up.

Fast isolation of recombinant baculovirus by antibody screening.

We describe a rapid and efficient scheme for the isolation and purification of recombinant baculoviruses. The method is based on the detection of foreign proteins in cellular lysates of baculovirus-infected insect cells by antibody screening. The recombinant virus is purified by repeated serial dilutions. The method allows the identification and purification of recombinant viruses within 2 to 3 wk. This procedure selects for recombinant baculoviruses that highly overproduce the desired protein product.