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At least 145 records · Page 8Linked to original sources

Comparison of immune response against Orientia tsutsugamushi, a causative agent of scrub typhus, in 4-week-old and 10-week-old scrub typhus-infected laboratory mice using enzyme-linked immunosorbent assay technique.

Using the indirect enzyme-linked immunosorbent assay (ELISA) technique, we compared the immune response of specific antibodies (IgM and IgG) in serum samples of scrub typhus-infected and non-infected mice against Orientia sutsugamushi (a causative agent of scrub typhus). Two different age groups (4-week-old and 10-week-old) of ICR laboratory mice were infected with O. tsutsugamushi by the animal passage procedure. Serum samples were detected for scrub typhus-specific antibodies using ELISA technique. Results from determining the presence of IgM and IgG in the serum samples obtained from scrub typhus-infected mice showed that the IgG was first detected on day-13 after the initial infection in both the 4-week-old and 10-week-old mice. The IgG titer levels of both groups were not significantly different. Although the presence of IgM in the in serum samples obtained from scrub typhus-infected mice was first detected on day 13 in the 4-week-old mice and on day-12 in the 10-week-old mice, the IgM titer in the 4-week-old mice was slightly lower than in the 10-week-old mice. Clinical observations of the scrub typhus-infected mice showed that the older mice become ill on day 9 whereas the younger mice exhibited the symptoms on day 12. Considering the earlier detection and slightly higher level of specific IgM antibody, it could be interpreted that the older mice may appear to have responded against O. tsutsugamushi faster than the younger mice.

Aging↗

Detection and treatment of bloodstream infection: laboratory reporting and antimicrobial management.

We analyzed antimicrobial use in 509 episodes of clinically significant bloodstream infection to assess the impact that microbiology laboratory reporting had on antimicrobial management. Most therapy interventions occurred at the time of phlebotomy and after notification of Gram stain results by telephone. Release of antimicrobial susceptibility data had the least impact on antimicrobial management.

Anti-Bacterial Agents↗

Genital herpes simplex virus infections: laboratory confirmation in diverse patient groups.

The laboratory diagnosis of genital herpes simplex virus (HSV) infections in various patient groups with diverse clinical manifestations including asymptomatic pregnant women with history of genital herpes and in a high prevalence group consisting of male patients with recurring genital ulcerations is described. HSV was detected by conventional cell culture and also by a CPE-enhancement technique using human embryonic lung fibroblasts (MRC-5) and Vero cells with subsequent typing of isolate by HSV type-specific monoclonal antibodies. A definite improvement in HSV diagnosis was noted by the use of the CPE-enhancement technique with the reduction of turn-around time to 24 h at which 61.1% and 50% isolation rates were detected in MRC-5 cells in comparison to 38.9% and 16.6% by conventional cell culture in the high prevalence patient population and asymptomatic pregnant women, respectively. Delayed development of CPE and reduced isolation rates were detected using Vero cells. Follow-up sampling of subsequent episodes of genital ulcerations in those with history of recurrence but an initial negative cell culture result, increased the isolation rate substantially and enabled the confirmation of diagnosis of genital HSV infection.

Cells, Cultured↗

[Dhori virus--a causative agent of human disease. 5 cases of laboratory infection].

The materials presented in the paper are first indications of the pathogenicity of Dhori virus for man and prove the role of this agent in the occurrence of 5 cases of the disease in laboratory workers accidentally infected during the preparation of cultural agents. Clinically, Dhori infection was characterized by an acute course with marked general toxicity and a febrile period of 2 to 4 days. Two out of 5 patients had changes on the part of the nervous system of the type of encephalitic reaction predominantly with subcortical symptoms and mild involvement of the pyramidal system or in the form of encephalopolyradiculoneuritis with paresthesia and sensitivity disorders.

Acute Disease↗

The early sporogonic cycle of Plasmodium falciparum in laboratory-infected Anopheles gambiae: an estimation of parasite efficacy.

This study investigated the successive losses in the parasite densities of Plasmodium falciparum stages during the early sporogony in laboratory-reared Anopheles gambiae infected by membrane feeding with blood from naturally infected gametocyte carriers (>50 gametocytes/mm3). The developmental stages of P. falciparum in the mosquito were studied from zygote to oocyst, by immunofluorescent method using monoclonal antibodies against the Pfs25 protein present on the surface of newly formed gametes. This method allows for assessment of the various sporogonic stages before, during and after passage of the midgut wall. Parasite densities were determined within the entire blood meal at 3 h (zygotes and macrogametes) and 24 h (ookinetes) post-infection. At 48 h after the mosquito blood meal, midguts were checked for the presence of early oocysts. For the mid-size oocysts count, classic microscopy examination was used at day 7 postinfection. The parasite efficacy was estimated by following successive losses in parasite densities between different early stages of the sporogonic cycle in A. gambiae. Thirty-seven experimental infections were realized with high gametocyte densities, ranging from 64 to 2392 gametocytes/mm3. All gametocyte carriers showed infection with round forms 100%; ookinetes were found in 91.9%. The prevalences of infections with oocysts were 48.6% at day 2 (young oocyst) and 37.8% at day 7 (mid-size oocyst). The mean densities per mosquito for each parasite stage were 12.6 round forms, 5.5 ookinetes, 1.8 young oocyst and 2 mid-size oocysts. Significant correlations were found between two consecutive parasite stages (round forms/ookinetes, ookinetes/young oocysts, young oocysts/mid-size oocysts) and between round forms and mid-size oocysts. The mean parasite density significantly decreased between round forms and ookinetes (yield Y1 = 41.6%) and between ookinetes and young oocysts (Y2 = 61.4%). By contrast, no significant decrease was observed between young oocysts and mid-size oocysts (Y3 = 91.2%). The overall yield of the early sporogonic cycle (from round form to oocyst at day 7) was equal to 25.7%, indicating that almost 3/4 of the total parasites were lost during the early step of the sporogonic cycle, from 3 h post-infection to day 7.

Animals↗

Reversal of human immunodeficiency virus type 1 IIIB to a neutralization-resistant phenotype in an accidentally infected laboratory worker with a progressive clinical course.

The role of humoral immunity in controlling human immunodeficiency virus type 1 (HIV-1) is still controversial. The resistance of primary HIV-1 variants to neutralization by antibodies, sera from HIV-1-infected patients, and soluble CD4 protein has been suggested to be a prerequisite for the virus to establish persistence in vivo. To further test this hypothesis, we studied the neutralization sensitivity of two IIIB/LAV variants that were isolated from a laboratory worker who accidentally was infected with the T-cell-line-adapted neutralization-sensitive IIIB isolate. Compared to the original virus in the inoculum, the reisolated viruses showed an increased resistance to neutralization over time. The ratio of nonsynonymous to synonymous nucleotide substitutions in the envelope gene pointed to strong positive selection. The emergence of neutralization-resistant HIV preceded disease development in this laboratory worker. Our results imply that the neutralization resistance of primary HIV may indeed be considered an escape mechanism from humoral immune control.

Amino Acid Sequence↗

Diagnostic techniques for evaluating herpes simplex virus infections. Laboratory considerations.

Recent advances in the management and treatment of genital herpes simplex virus (HSV) infections underscore the importance of timely and accurate diagnosis of the disease. Moreover, increased physician awareness of the importance of accurately diagnosing herpes has led to a better understanding of its natural history. Like all diagnostic medical devices, microbiologic tests used to diagnose HSV infections are subject to governmental regulations. Based on the current status of available testing and our knowledge of the nature of HSV, clearly there is still much to be learned about HSV infections. The answers to some key questions will provide advances in diagnostic expertise and, ultimately, in the effective treatment and prevention of HSV-associated illness.

Antibodies, Viral↗

Laboratory infections of Culicoides debilipalpis and C. stellifer (Diptera: Ceratopogonidae) with bluetongue virus.

Six species of field-collected Culicoides females were used in preliminary laboratory tests: C. biguttatus, C. debilipalpis, C. obsoletus, C. stellifer, C. variipennis and C. venustus. Tests were conducted to determine if females would take a blood meal through a membrane, if blood fed females could be maintained in the laboratory for up to 14 days and if they could support replication of bluetongue virus (BTV) serotype 11. One pool of C. stellifer (23 specimens) assayed positive for BTV 7 days following intrathoracic inoculation, which datum suggests that this species might be capable of harboring the virus. One of 52 individually assayed C. debilipalpis females in 2 trials was positive for BTV at 14 days after membrane feeding on a mixture of BTV and sheep blood (infection rate 1.9%), and 1 of 2 pools of C. debilipalpis (26 specimens) was positive 14 days after blood feeding. These data for C. debilipalpis showed that the species can pick up and harbor BTV through replication of the virus.

Animals↗

[Comparative efficiency of infecting laboratory animals via intravenous and subcutaneous administration of Schistosoma mansoni cercaria].

Comparative study on effectiveness of intravenous and subcutaneous methods of infection of animals has shown that infection rate of helminths after the injection of equal dozes of cercariae under skin, into portal and femoral veins of golden hamsters does not differ significantly (42.6 +/- 4.2, 37.8 +/- 5.8 and 26.0 +/- 6.6 schistosomes, respectively). When using the above methods for cotton rats the infection rate was lower than that in golden hamsters. The most insignificant infection rate of parasites was recorded in both species after the injection of cercariae into the femoral vein. Results of the infection of golden hamsters with different dozes of cercariae have shown that with the increase of dozes of infectious material the infection rate of helminths rises during the experimental intestinal schistosomiasis only to a definite level, which is attained by the injection of cercariae into the portal vein in dozes lower than those used for subcutaneous infection.

Animals↗

Sisomicin in surgical infections. Laboratory and clinical studies.

A clinical and bacteriological study to evaluate the effectiveness and toxicity of sisomicin in the treatment of surgical infections is described. Fifteen patients received i.m. injections of 150 or 225 mg/day for seven days. The daily doses was divided into three applications. The mean serum levels at the first hour were 5.26 +/- 2.41 microgram/ml and at the seventh hour 1.0 +/- 1.19 microgram/ml. Similar values were determined on the seventh day of treatment with sisomicin: 6.36 +/- 2.36 microgram/ml one hour, 1.17 +/- 1.67 microgram/ml seven hours after i.m. injection. All the microorganisms isolated had MICs below the sisomicin levels measured. The clinical results were assessed as "excellent" in 11 patients. Therapeutic results were considered as "fair" in three patients. The clinical conditions of one patient affected by osteomyelitis following osteosynthesis of the femur was not improved by treatment. No side effects were observed.

Adolescent↗

Is pinworm a vanishing infection? Laboratory surveillance in a New York City medical center from 1971 to 1986.

Records of our parasitology laboratory were reviewed to determine trends in the frequency of specimens submitted for diagnosis of pinworm infection, the proportion of such specimens that were positive, and the proportion of such positive results for the pediatric age group from 1971 to 1986 in a major New York City medical center. These data demonstrate a markedly declining trend in the absolute number of sticky tape tests sent for pinworm diagnosis, from 248 in 1971 to 38 in 1986, an average of 8% decline per year. The number of specimens identifying Enterobius vermicularis among those submitted has similarly declined, from 57 in 1971 to none being positive in 1986, an average of 16% decline per year. The dramatic decline in pinworm identification and the fall in the number of specimens sent by practitioners at this medical center, and reported elsewhere in the United States by other investigators, may reflect a genuine decline in oxyuriasis occurring in the patient populations served.

Adolescent↗