More laboratories should test for Dientamoeba fragilis infection.
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Clinical Laboratory Techniques↗
Biomedical subjects
E H Johnson
Publications and source records attributed to E H Johnson.
The ultrastructural morphology of the camel eosinophil.
The ultrastructural morphology of the eosinophil was studied in specimens of peripheral blood from normal adult camels and those with eosinophilia. Specific granules were extremely polymorphic. The specific granules exhibited the basic structure of an electron-dense crystalloid core surrounded by a lighter, homogeneous matrix. The crystalloid cores were extremely variable in size and shape, often were segmented and demonstrated a variety of lamellated patterns that were transverse, longitudinal or concentric to the long axis of the core. It was not uncommon to observe multiple crystalloid cores in a single granule. In addition to large specific granules, microgranules and specific microgranules were observed. The extreme polymorphism of the specific granules and variety of lamellated patterns differentiate camel eosinophils from those of other species.
Animals↗
Immune responses to third stage larvae of Onchocerca volvulus in interferon-gamma and interleukin-4 knockout mice.
To shed clarity on the dichotomy of reported results relative to the significance of T helper-1 vs T helper-2 immune responses in onchocerciasis, we compared the survivability of Onchocerca volvulus third-stage larvae (L3) in immunized mice that had either a targeted disruption of the Interleukin-4 or Interferon-gamma gene. Treatment groups consisted of control mice and mice immunized with irradiated O. volvulus L3. All mice were challenged with diffusion chambers containing viable L3. Vaccinated IL-4-/- were unable to kill this larval target. In contrast, vaccinated INF-gamma-/- and C57BL/6 mice, exhibited high levels of killing, had elevated levels of IL-4 and significantly greater numbers of eosinophils in their diffusion chambers than the IL-4-/-. Whereas, levels of IFN-gamma in all three groups of immunized mice were equivalent to those of control mice, levels of IL-5 were elevated, even in the IL-4-/-, indicating that cytokines other than IL-4 were involved in its production. The protective immune response to third-stage larvae of O. volvulus in mice vaccinated with irradiated larvae has an absolute IL-4 requirement.
Animals↗
Incidence of Dientamoeba fragilis in faecal samples submitted for routine microbiological analysis.
Over a six-month period, 857 faecal samples were submitted to the Department of Microbiology and Immunology at Sultan Qaboos University Hospital in Oman, for routine microbiological examination. All samples were stained using the Gomori trichrome method. Trophozoites of Dientamoeba fragilis were detected in 41 (5.1%) patients, making it the most common enteropathogen found in the study. Of the patients with pure D. fragilis infection, 83% had abdominal pain, the duration of which varied from one month to two years. The use of permanently stained smears allowed detection of D. fragilis for the first time in the Sultanate of Oman.
Adolescent↗
Identification of larval-stage-specific antigens of Onchocerca volvulus uniquely recognized by putative immune sera from humans and vaccination sera from animal models.
Immunity to Onchocerca volvulus is indicated by the existence of putative immune individuals (PI), who do not develop patent infections or clinical symptoms after living in endemic areas for extended periods of time. To gain insight into the nature of the humoral response of PI from Liberia and Ecuador, their sera and those of infected individuals were investigated and compared using western blots. The antigen preparations used were extracts of third- and fourth-stage larvae (L3 and L4, respectively), excretory-secretory proteins (ES-L3) and extracts of third-stage larvae (L3-day2) that had been cultured for 2 days, and extracts of nodular and skin microfilariae. Whereas some antigens were commonly recognized by all individuals, many stage-specific antigens (of 68, 60, 55, 46, 43, 42, 20 and 18 kDa in L3; 100, 88, 80, 50, 48, 45, 40 and 20 kDa in L3-day2; 110, 80 and 72 kDa in ES-L3; 48, 18, 16 and 14 kDa in L4; and 115, 60, 47, 43 and 17 kDa in skin and/or nodular microfilariae) were uniquely recognized by sera from PI. Some of the unique antigens were also recognized by sera from mice and a chimpanzee that were resistant to challenge after immunization with irradiated third-stage larvae. The results support the validity of the assumption that a unique status of immunity develops in certain individuals living in areas where onchocerciasis is endemic.
Animals↗
The efficacy of the health belief model for predicting condom usage and risky sexual practices in university students.
This investigation examined the ability of the health belief model (HBM) to predict condom usage and risky sexual practices in 122 white heterosexual college students (ages 17 to 33 years). The HBM did not significantly explain condom usage in the 58 men and 64 women surveyed; rather it partially explained the variance in sexual risk behaviors. Results were not consistent for men and women. The HBM components significantly explained 18% of the variance in multiple sexual partnerships in men and 22% of the variance in this behavior in women. The HBM constructs also explained 9% of the variance in the likelihood of women being intoxicated or high during sex and 18% of the variance in the number of sexual risk behaviors endorsed by women. These findings suggest that the HBM has differential and limited utility for predicting sexual practices in university students. Future research is needed to examine more comprehensive models of behavior change.
Acquired Immunodeficiency Syndrome↗
Prostatic acid phosphatase levels (enzymatic method) from completely sectioned, clinically benign, whole prostates.
Clinically benign, whole untrimmed prostates were obtained from 104 patients at autopsy, completely sectioned, and examined microscopically. The histological and gross findings of the prostate were correlated with premortem prostatic acid phosphatase levels (PAP, enzymatic method, ACA, Dupont Co.) to determine how often carcinoma of the prostate (CAP) affected PAP levels and to identify other findings within the prostate associated with elevated PAP levels. Sixty (58%) prostates did not have CAP, 34 (33%) had CAP smaller than 1 ml in volume, and 10 (10%) had CAP larger than 1 ml in volume. PAP levels were elevated (greater than 1 U/L) in 8 of 60 (13%) prostates without CAP, in 2 of the 34 (6%) prostates with CAP smaller than 1 ml, and in 1 of the 10 (10%) prostates with CAP larger than 1 ml. These differences were not statistically significant. Likewise, a statistically significant correlation between PAP levels and patient age, patient race, severe inflammation, of high grade prostatic intraepithelial neoplasia (PIN) was not found. However, there was a statistically significant correlation between PAP levels and prostate weight (p < 0.0001). This study suggest that PAP cannot distinguish between patients with clinically undetected CAP and patients without CAP. Furthermore, elevated PAP levels are often not due to metastatic CAP and additional evidence should be present, even in patients with known CAP, before an elevated PAP level is considered to be conclusive evidence of metastatic CAP.
Acid Phosphatase↗
Characteristics of African-Americans with multiple risk factors associated with HIV/AIDS.
Multiple risk factors in young African-Americans have tremendous implications for the spread of AIDS. Two hundred forty-two heterosexual college students were classified as having low, moderate, or high risk for HIV infection based upon their self-reported sexual practices. Results indicated that subjects differed in AIDS knowledge and attitudes toward condoms with respect to both Gender and Risk level, with men and High Risk individuals being less knowledgeable and having more negative attitudes than their female and Low Risk counterparts respectively. Interaction effects revealed that High Risk men were less knowledgeable than both Low Risk men and High Risk women. High Risk men as well as High and Low Risk women reported more anger surrounding condom usage than Low Risk men. Low perceptions of vulnerability for AIDS were reflected in the entire sample. The implications of this study for primary prevention and future research are discussed.
Adult↗
Colonic adenocarcinoma in a rhesus macaque (Macaca mulatta).
A spontaneous colonic adenocarcinoma and endometriosis was diagnosed in a 34-year-old female rhesus macaque (Macaca mulatta). The tumor caused partial obstruction of the ascending colon and histologically resembled the commonly described napkin-ring tumors of the descending and sigmoid colon found in humans. Serum levels of CA 125, a high-molecular-weight glycoprotein antigen that has been reported elevated in a variety of pathological conditions of the pelvic cavity in humans, was severely elevated. Both the adenocarcinoma and the endometriosis may have contributed to this finding.
Adenocarcinoma↗
Obesity and hypertension among African Americans: do African-American primary care providers address these conditions when secondary to primary illness?
This study examined the extent that black family medicine residents manage African-American patients with hypertension and obesity secondary to the primary health problem. A retrospective chart survey of 1806 outpatients was used to select a sample of 362 patients being treated by 12 African-American family medicine residents. Of the 362 patient charts, 31.2% of the patients had hypertension (ie, blood pressure > or = 140/90 mm Hg). A plan for managing hypertension was found in the charts for 77% of these patients. Obesity was present among 37% of the patients, and yet there was documentation of a treatment plan for managing this condition for only 38% of these patients. Black family medicine residents appear to be sensitized about addressing the problem of hypertension among African-American patients being treated for other illnesses. However, there is a vital need to teach family medicine physicians how to address and aggressively manage the problem of obesity among African-American patients, particularly those patients for whom obesity was not the primary reason for seeking medical care.
Black People↗
Onchocerca volvulus: a comparative study of in vitro neutrophil killing of microfilariae and humoral responses in infected and endemic normals.
In vitro neutrophil-mediated microfilarial killing, humoral responses to crude adult worm antigens (OVAg) and to four recombinant Onchocerca antigens (GST-OV7, GST-OV103, GST-OV3.6, and MBP-OV16), as well as Western blot analysis to stage-specific Onchocerca proteins were studied in individuals from Bassa County, Liberia, infected with onchocerciasis and in endemic normals, defined as individuals without microfilaridermia. Both groups exhibited high levels of specific serum-dependent killing of microfilariae but could not be differentiated on the basis of these results. However, infected individuals had a significantly higher frequency of antibody response to OVAg (P = 0.0001) except GST-OV103. Based on the pattern of response to the different antigens, 17 categories of specific recognition were observed. Nine of these categories were common to both the infected individuals and the endemic normals, 2 were unique to the infected individuals, and 6 were unique to the endemic normals. Among the endemic normals, we identified a subcategory of individuals who had nondetectable levels of total IgG to OVAg by ELISA and had significantly lower IgG4 responses to OVAg. These same individuals demonstrated evidence of past infection, based on serum antibodies detectable by Western blot analysis to male and female adult worms and skin microfilariae, and had a positive response to two or less of the recombinant antigens. We believe that this subcategory may represent individuals with a unique status of immunity.
Adolescent↗
Incidence, racial differences, and prognostic significance of prostate carcinomas diagnosed with obstructive symptoms.
BACKGROUND: It is unknown how often prostate carcinomas are diagnosed as a result of urinary obstructive symptoms or whether prostate carcinomas diagnosed because of obstructive symptoms have a favorable or unfavorable prognosis. It is also unknown whether racial differences in obstructive symptoms could help explain why black men with prostate carcinoma are diagnosed with more advanced stages and grades of prostate carcinoma than are white men with prostate carcinoma. METHOD: At a single Veterans Administration Medical Center, 478 consecutive cases of prostate carcinoma diagnosed between 1973 and 1985 were identified. The incidence of obstructive symptoms at diagnosis, racial differences in obstructive symptoms, and the survival of patients with and without obstructive symptoms, stratified by stage and grade, were determined. In addition, racial differences in the frequency of surgical intervention required to relieve the obstructive symptoms were determined. RESULTS: All patients diagnosed with Stage A prostate carcinoma and most (82%) patients diagnosed with Stage C prostate carcinoma had obstructive symptoms. Those diagnosed with Stage B and Stage D prostate carcinomas had with similar frequencies (53% and 55%, respectively) of obstructive symptoms. Survival, stratified by stage and grade, was similar for men with and without obstructive symptoms. The incidences of obstructive symptoms and the frequency of surgical intervention to relieve the obstructive symptoms, stage for stage, were similar for white and black men. CONCLUSION: Survival, stratified by stage and grade, is not affected adversely by obstructive symptoms. Neither racial differences in the incidence of obstructive symptoms nor the frequency with which obstructive symptoms require surgical correction explain why black men with CAP consistently are diagnosed more frequently with Stage D prostate carcinoma and less frequently with Stage A CAP than white men with CAP.
Adult↗
Psychopathology and anger in interpersonal violence offenders.
The current literature on psychopathology and anger suggests that both contribute to interpersonal violence. The present study examined psychopathology and anger expression with two objectives: to confirm previous distinctions of personality type among abusive individuals and to examine the relation between these types and anger. Cluster analysis was conducted with data gathered from 40 subjects. Results suggested confirmation of four clusters of interpersonal violence offenders. Furthermore, the most pathological cluster type reported the highest level of total anger experience, while the histrionic cluster type reported the lowest anger expression. These results provide tentative support for a positive relationship between psychopathology and anger, as well as for the distinction between overcontrolled and under-controlled anger as subtypes of interpersonal violence offenders.
Adolescent↗
Identification of trisomy in Macaca fascicularis by fluorescence in situ hybridization with a human chromosome 13 DNA library.
A juvenile macaque monkey with abnormal phenotypic and behavioral features was studied cytogenetically. An additional autosome was found in over 90% of the animal's cultured cells. This chromosome, subsequently identified as number 16 in the macaque karyotype by G-banding, was shown to be mostly homologous with human chromosome 13 using fluorescence in situ hybridization of a human chromosome specific cosmid library. Although the monkey, now deceased, exhibited some abnormal physical and behavioral features, none of the severe clinical characteristics associated with human chromosome 13 trisomy were apparent. We suggest that the incomplete expression of 13-trisomy observed could result if the macaque chromosome were deficient in some of the region(s) of chromosome 13 common to humans affected with the disorder.
Animals↗
Characteristics of prostatic infarcts and their effect on serum prostate-specific antigen and prostatic acid phosphatase.
OBJECTIVES: To determine how prostatic infarcts affect serum prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) levels. METHODS: Two hundred eighteen clinically benign, whole prostates were obtained at autopsy, completely sectioned, and examined histologically. PSA and PAP levels were determined from premortem serum. RESULTS: Six of the 218 (2.8%) prostates had infarcts. The infarcts were usually multiple and usually located in the central and/or middle concentric zones of the middle third of the prostate without a preference for a particular lobe. Serum PSA by immunoradiometric assay were elevated in all 6 cases. Serum PAP by both enzymatic assay (ACA), and immunoradiometric assay were available for 5 cases and were elevated by both methods in 2 cases, approached elevated levels by both methods in 1 case, and were normal by both methods in 2 cases. The PSA and PAP levels appeared to be affected more by the age than by the size of the infarct. CONCLUSIONS: Prostatic infarcts elevate PSA levels more frequently than PAP levels, and prostatic infarcts may be responsible for some unexplained elevations of serum PSA and PAP levels.
Acid Phosphatase↗
Long-term survival of stage A prostate carcinoma, atypical hyperplasia/adenosis and BPH.
Between 1972 and 1986, 134 patients with stage A carcinoma of the prostate (CAP) were diagnosed at a single Veterans Administration medical centre and followed annually by the hospital tumour registry. Seventy-four were classified as stage A1, defined as non-palpable, well-differentiated CAP, regardless of amount, found unexpectedly on transurethral resection of the prostate (TURP). Twenty-eight were classified as stage A2, defined as non-palpable, moderately or poorly differentiated CAP, regardless of amount, found unexpectedly on TURP. The remaining 32 were reclassified as atypical hyperplasia/adenosis (AH/A) rather than CAP. The survival of each group was compared with the survival of a control group from the same medical centre who had TURPs showing histologically proven benign prostatic hyperplasia (BPH). Survival and tumour progression were similar for patients with stage A1 CAP, AH/A and BPH. Furthermore, patients with stage A1 CAP, with or without therapy, had similar survivals as patients with BPH in each age group (under 65, 65-74 and over 74 years). Stage A2 CAP was associated with a significantly worse survival and more tumour progression. Within stage A1 CAP and stage A2 CAP the percentage of chips with CAP or the amount of CAP removed did not affect survival.
Adult↗
Onchocerca volvulus: in vitro cytotoxic effects of human neutrophils and serum on third-stage larvae.
The cytotoxic effects of neutrophils co-cultured with infective third-stage larvae (L3) and autologous serum from three groups of individuals: infected (INF), non-patent endemic normals (EN) and non-endemic controls (NEC), were compared using a MTT (3-(4,5 dimethylthiazol-2yl)-2,5 diphenyl tetrazolium bromide) reduction assay as a biochemical parameter of larval viability. The MTT assay permitted the detection of L3 which had suffered varying levels of necrosis. The observations from this study indicate that infected individuals and endemic normals are capable of mounting a specific immune response against the infective L3. This is based on our findings of i) significantly greater numbers of L3 showed necrosis in neutrophil cultures of the INF and EN compared to those from the NEC, ii) a superior ability of cultures from these individuals to inhibit the molting of L3 to fourth-stage larvae, iii) IgG antibodies reactive with the surface of L3, detected by immunofluorescence in the serum of the INF and the EN and iv) recognition of specific antigens in extracts of L3 detected by Western blot analysis. The specific immune response directed against L3 is probably a significant immunological defense mechanism used to limit infection in endemic areas.
Adolescent↗
What is the significance of black-white differences in risky sexual behavior?
A sample of African-American and white young adults were classified as having multiple sex partners or one sexual partner. Subjects with multiple sexual partners were more likely to use drugs and practice risky sexual behaviors such as having anal intercourse, having sexual experiences with a prostitute, and having a history of gonorrhea (P < .001) and genital warts (P < .01). Additional analyses were conducted to determine African-American versus white differences in risky sexual behaviors. Results indicated that whites in the multiple partners and single partner groups were more likely to engage in anal and oral sex, while African Americans were more likely to have sex with prostitutes. Attitudes about the use of condoms differed significantly by multiple partner status (P < .004) and gender (P < .007), but not ethnicity. However, angry reactions about the use of condoms occurred more with African Americans (P < .003) and males (P < .05) than with whites or females. While whites reported a greater use of drugs and a significantly higher level of knowledge about HIV/AIDS, African Americans reported a significantly greater perception of risk for being exposed to human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) (P < .01) and significantly more gonorrhea (P < .10), syphilis (P < .05), and HIV/AIDS (P < .05). No whites in our sample were treated for syphilis nor had they tested positive for HIV/AIDS. On the other hand, 4.5% of the total sample of African Americans reported testing positive for HIV/AIDS. Finally, the results from discriminant analysis indicate that a large number of variables significantly discriminate between subjects who engage in risky sexual behaviors and those who do not. Although there is some similarity in the variables for African Americans and whites, there was tremendous variability between the ethnic groups in the factors that predict risky behaviors. These findings are discussed with reference to the need to develop HIV/AIDS prevention programs for African Americans that are based on data derived from African-American populations rather than from black versus white comparison studies.
Acquired Immunodeficiency Syndrome↗