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Biomedical subjects

A Manns

Publications and source records attributed to A Manns.

At least 73 records · Page 4Linked to original sources
PubMed1993

The immediate effect of the variation of anteroposterior laterotrusive contacts on the elevator EMG activity.

A unilateral maxillary splint divided into three occlusal blocks was built for eight healthy young adults. The three blocks allowed the anteroposterior location of the laterotrusive contacts to vary and to distribute the occlusal force over equivalent periodontal surfaces. The ipsilateral masseteric and temporalis electromyogram (EMG) activities were recorded with surface electrodes during maximal voluntary clenching. The elevator EMG activity with the anterior occlusal block in place was significantly lower than with the intermediate or posterior blocks. The reduction for both elevators with the intermediate block in place did not show a significant variation in comparison to the posterior block of the three blocks inserted. The elevator activity with the three occlusal blocks did not differ from that recorded with the posterior block alone. Neurophysiologic and biomechanical explanations are given related to this laterotrusive elevator muscular behavior.

Adult↗
PubMed1993

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.

Adolescent↗
PubMed1992

A prospective study of transmission by transfusion of HTLV-I and risk factors associated with seroconversion.

To evaluate the risk of transfusion-related transmission of HTLV-I in Jamaica, a prospective study was initiated, prior to availability of a licensed HTLV-I serological screening assay. This information would prove useful in formulating strategies for blood-donor screening. We followed 118 pre-transfusion HTLV-I-negative transfusion recipients at monthly intervals post-transfusion for 1 year. Laboratory and questionnaire data were obtained at each visit to evaluate the clinical and immunological status of recipients. Cumulative incidence of HTLV-I seroconversion was estimated and risk-factor data associated with seroconversion among 66 HTLV-I-exposed transfusion recipients were analyzed. Seroconversion occurred in 24/54 (44%) of recipients of HTLV-I-positive cellular blood components, 0/12 recipients of positive non-cellular donor units and 0/52 recipients of HTLV-I-negative donor units. Significant risk factors associated with recipient seroconversion were receipt of a seropositive cellular blood component stored for less than one week [odds ratio (OR) = 6.34, 95% confidence interval (CI) = 1.83 to 21.92], male sex (OR = 4.79, 95% CI = 1.15 to 20.0) or use of immuno-suppressive therapy at time of transfusion (OR = 12.20, 95% CI = 0.95 to 156). Risk of blood-borne infection per person per year in Jamaica was estimated to be 0.009%. Our results confirm that blood transfusion carries a significant risk of HTLV-I transmission and that screening of donor blood effectively prevents HTLV-I seroconversion. Recipients at greatest risk for seroconversion were those who required multiple transfusions or who were receiving immunosuppressive therapy at the time of transfusion. These patients should be given priority in receiving selectively screened blood components, if universal blood-donor screening for HTLV-I is not possible.

Blood Donors↗
PubMed1992

Expression of alternatively spliced human T-lymphotropic virus type I pX mRNA in infected cell lines and in primary uncultured cells from patients with adult T-cell leukemia/lymphoma and healthy carriers.

Although human T-cell lymphotropic virus type I (HTLV-I) is the etiologic agent of adult T-cell leukemia/lymphoma (ATL), the role of viral gene expression in the progression to and maintenance of the leukemic state in vivo is unclear because of the inability of most previous studies to readily detect HTLV-I RNA in infected individuals. By using the reverse transcriptase-polymerase chain reaction, we detected spliced messages for the HTLV-I pX regulatory genes in primary uncultured cells from ATL patients and healthy asymptomatic carriers. In addition to the expected doubly spliced pX message, three alternatively spliced mRNAs were demonstrated (pX delta 17, pX-p21rex, and pX-orfII mRNAs, where orf = open reading frame). The same splice sites were shown in the messages from uncultured ATL cells and from the HTLV-I-producing C10/MJ cell line. Alternatively spliced pX mRNAs have the potential to code for known and putative pX gene products. Among the transcripts is a monocistronic mRNA likely to code for p21rex (pX-p21rex mRNA). Since alternative splicing of HTLV-I pX mRNA can be found in primary uncultured cells, it is likely to have a functional significance in vivo. This suggests possible roles for HTLV-I gene expression in the progression to and maintenance of ATL, as well as in the phase preceding it.

Base Sequence↗
PubMed1992

Influence of mucosal mechanoreceptors on anterior temporalis EMG activity in patients with craniomandibular dysfunction: a preliminary study.

An analysis of saliva swallowing and tonic electromyographic (EMG) activity was undertaken in 15 young adult patients with craniomandibular dysfunction with and without a palatal base inserted. Recordings were performed by placing surface electrodes on the right and left anterior temporal muscles. Saliva swallowing and tonic activity were initially recorded with and without the palatal base inserted. After one week of continuous use of the palatal base, EMG activity was recorded again. Nonsignificant differences in EMG activity were observed in the studied conditions. EMG results do not support the therapeutical use of palatal base as a conservative and reversible treatment in patients with craniomandibular dysfunction.

Adult↗
PubMed1991

Detection of early human T-cell lymphotropic virus type I antibody patterns during seroconversion among transfusion recipients.

From a cohort of human T-cell lymphotropic virus type I (HTLV-I) exposed transfusion recipients (N = 71) enrolled in the Jamaican Transfusion Study, 11 were selected for detailed laboratory evaluation. All recipients were followed at monthly intervals for 6 months and then bimonthly up to 1 year for evidence of HTLV-I seroconversion. Without regard to results on screening assays, pretransfusion and posttransfusion samples were tested with two licensed HTLV-1 whole-virus screening enzyme immunoassays (EIAs), recombinant EIAs for antibody against tax (p40x) and p21e envelope, standard whole virus Western blot (WB), WB enhanced with recombinant p21e, and radioimmunoprecipitation assay (RIPA). In the early period posttransfusion, antibody to gag core protein was predominant with anti-p24 generally appearing before anti-p19. Recombinant anti-p21e envelope protein, in EIA and WB format, was frequently the earliest envelope reactivity detected, while anti-gp46 in WB and anti-gp61/68 in RIPA system appeared later. Anti-tax antibodies appeared later in the time course of seroconversion. The whole-virus EIAs were less sensitive than the confirmatory assays. The combination of WB and RIPA or WB enhanced with recombinant p21e appeared equally effective in confirming samples as positive by the Public Health Service two gene group confirmatory algorithm. However, specificity of this assay approach could not be addressed in this study.

Adolescent↗
PubMed1991

Fidelity of reverse transcriptase of the simian immunodeficiency virus from African green monkey.

The in vitro fidelity of highly purified recombinant reverse transcriptase from simian immunodeficiency virus of African green monkeys (SIVagm) was determined. By using the phi X174am16 reversion assay an overall error rate of 1/19,000 was determined. This is 2.4-fold higher than the overall accuracy of purified recombinant HIV-1 reverse transcriptase, measured in parallel. The evaluation of error frequencies from nucleotide pool bias studies suggest an even higher accuracy for the SIVagm-derived reverse transcriptase. T:dGMP mismatches were formed most frequently with an error rate of 1/155,000, followed by G:dGMP (1/230,000), A:dGMP (1/315,000), G:dAMP (1/340,000), T:dCMP (1/540,000), T:dTMP (1/790,000), and A:dCMP (1/1,050,000) mispairs. Thus, according to pool bias effects and depending on the mismatch under consideration SIVagm reverse transcriptase appears to be 2 to 20-fold more accurate than the homologous enzyme from the human immunodeficiency virus type 1. This higher accuracy is not due to a co-purifying exonuclaease activity. Like the enzyme from HIV-1, the simian monkey-derived enzyme was found to be devoid of a proofreading 3' to 5' exonuclease.

Animals↗
PubMed1991

Cytokine induction in HTLV-I associated myelopathy and adult T-cell leukemia: alternate molecular mechanisms underlying retroviral pathogenesis.

The human T-cell lymphotropic virus type I (HTLV-I) is capable of inducing a variety of host cellular genes including many of the cytokines responsible for immune regulation and osteoclast activation. This derangement in cytokine expression may contribute to the panoply of disease states associated with HTLV-I infection such as the adult T-cell leukemia (ATL) and HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP). We wished to determine if there was a correlation between the expression of an array of cytokines and the diverse clinical manifestations of ATL and HAM/TSP. Utilizing the techniques of specific mRNA amplification by the polymerase chain reaction (PCR) as well as Northern blotting, we analyzed the ex vivo mRNA expression of gamma-interferon (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and transforming growth factor-beta 1 (TGF-beta 1) in the peripheral blood of HAM/TSP and ATL patients as well as asymptomatic seropositive carriers. IFN-gamma, TNF-alpha, and IL-1 beta transcripts were up-regulated in patients with HAM/TSP and seropositive carriers when compared to their levels in ATL and normal controls. In contrast, the ATL patients constitutively expressed higher levels of TGF-beta 1 mRNA than HAM/TSP and seropositive carriers. In addition, TNF-alpha and IL-1 beta serum levels were elevated in HAM/TSP, but not in ATL patients nor seropositive carriers. However, the circulating leukemic cells from ATL patients secreted increased levels of TGF-beta 1 protein into the culture medium than T-cells derived from HAM/TSP patients. Collectively these results suggest that induction of IFN-gamma, TNF-alpha, and IL-1 beta in HAM/TSP may initiate an inflammatory cascade with subsequent events leading to immune mediated destruction of the central nervous system in these patients. Expression of osteoclast activators such as TNF-alpha and IL-1 beta is not associated with hypercalcemia in ATL. Finally, impaired cellular and humoral immune responses present in ATL, but not in HAM/TSP, may be related to elevated levels of TGF-beta 1 produced by the leukemic cells. These differences in retroviral-induced host cytokine expression in ATL and HAM/TSP suggest alternate roles in disease pathogenesis.

Adult↗
PubMed1991

Patterns of electromyographic activity in subjects with different skeletal facial types.

Integrated electromyographic activity of masseter and anterior temporal muscles was recorded using bipolar surface electrodes in 33 young adults. Subjects were skeletally classified according to ANB angle reading corrected both for maxillary position and rotation of the jaw. Postural activity for both muscles was higher in Class III subjects than in Class I and Class II, whereas in Class I and II subjects activity was similar. During swallowing, masseter muscle activity in Class III subjects was higher than Classes I and II, whereas anterior temporal muscle activity was not different between Classes III and I. During maximal voluntary clenching, activity was not different among classes. High correlations between electromyographic activity and corrected ANB angle as well as with overjet were observed. Skeletal classification used in the present study may have clinical relevance regarding treatment and prognosis, as well as in the assessment of the relationship between muscular activity and craniofacial characteristics.

Adolescent↗
PubMed1991

Influence of occlusal splints on bilateral anterior temporal EMG activity during swallowing of saliva in patients with craniomandibular dysfunction.

A full-arch maxillary stabilization occlusal splint was made for each of 10 patients with craniomandibular dysfunction. These splints were divided into three sections (one anterior and two posterior). This procedure allowed variation in the anteroposterior centric localization of occlusal contacts, thus permitting the recording of the EMG effects produced by the different occlusal splint sections. The integrated EMG activity was recorded from the right and left anterior temporal muscles during swallowing of saliva in habitual occlusion and with the different occlusal splint sections inserted. EMG activity during swallowing of saliva was significantly lower with the different occlusal splints than in habitual occlusion. This supports the rationale for diurnal wear of the occlusal splint. No differences in EMG activity were found during swallowing of saliva when different sections of the occlusal splints were used. This fact points out the possibility for therapeutic use of different occlusal splints for improving swallowing function.

Adolescent↗
PubMed1991

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.

Animals↗
PubMed1990

Transactivation of interleukin 2 and its receptor induces immune activation in human T-cell lymphotropic virus type I-associated myelopathy: pathogenic implications and a rationale for immunotherapy.

A state of T-cell activation, reflected by a marked degree of spontaneous proliferation in vitro, exists among patients with human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) but not in those with retroviral-induced adult T-cell leukemia (ATL). We wished to define the mechanism by which the immune activation of circulating cells from HAM/TSP is driven, thus gaining insight into the pathogenesis of this HTLV-I-associated disease. By using a modification of the polymerase chain reaction, we compared the levels of interleukin 2 (IL-2) and IL-2 receptor alpha chain (IL-2R alpha) mRNA expression to the transcription of the HTLV-I transactivator gene, pX, in peripheral blood mononuclear cells of HAM/TSP and ATL patients as well as seropositive carriers. Up-regulation of IL-2 and IL-2R alpha transcripts was detected in HAM/TSP and seropositive carriers that paralleled the coordinate mRNA expression of the pX transactivator. In addition, IL-2 and soluble IL-2R alpha serum levels in HAM/TSP and seropositive carriers were elevated. Despite markedly elevated levels of soluble IL-2R alpha in ATL, transcripts for IL-2 and pX were not demonstrable in the circulating cells. Finally, the marked degree of in vitro spontaneous proliferation present in HAM/TSP was profoundly inhibited by specific anti-IL-2R or anti-IL-2 blocking antibodies. Collectively, these results suggest that immune activation in HAM/TSP, in contrast to ATL, is virally driven by the transactivation and coordinate expression of IL-2 and IL-2R alpha. This deregulated autocrine process may contribute to the evolution of inflammatory nervous system damage in HAM/TSP.

Base Sequence↗
PubMed1990

Relationship between the tonic elevator mandibular activity and the vertical dimension during the states of vigilance and hypnosis.

The variation of the tonic EMG elevator mandibular activity was studied as well as the consequent variation of the vertical dimension in two different experimental states: those of vigilance and hypnosis. In the state of vigilance, normal values of tonic EMG activity were recorded and a space of inocclusion (X = 2.22 mm) coincident with the postural mandibular position. Under hypnosis a significant reduction of the tonic EMG activity was observed (43 to 50%), together with a great increase of the inocclusion space (X = 8.90 mm).

Adolescent↗
PubMed1990

Development and evaluation of a human T-cell leukemia virus type I serologic confirmatory assay incorporating a recombinant envelope polypeptide.

A recombinant protein derived from the gp21 region of the human T-cell leukemia virus type I (HTLV-I) env gene was synthesized in Escherichia coli and purified by reversed-phase high-performance liquid chromatography. The purified protein was free of contaminating bacterial proteins and retained reactivity with human HTLV-I- and HTLV-II-positive sera and a gp21 monoclonal antibody. An immunoblot procedure using the recombinant polypeptide in conjunction with native viral proteins was more sensitive than the conventional immunoblot and radioimmunoprecipitation confirmatory assays for detection of antibodies to HTLV-I and HTLV-II env-encoded gene products. The recombinant protein was equally reactive with sera from polymerase chain reaction-confirmed HTLV-I or HTLV-II infections. Furthermore, on the basis of the differential reactivities of gp21-positive sera with the HTLV-I p19 and p24 gag-encoded proteins, an algorithm was proposed to distinguish exposure to HTLV-I from exposure to HTLV-II. These results establish the utility of a modified immunoblot assay incorporating a recombinant envelope polypeptide as an alternative to existing HTLV-I-confirmatory assays.

Antibodies, Viral↗