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Biomedical subjects

A King

Publications and source records attributed to A King.

At least 145 records · Page 8Linked to original sources
PubMed1999

Molecular epidemiology of cryptosporidiosis outbreaks and transmission in British Columbia, Canada.

Isolates from 25 (13 sporadic and 12 outbreak) cryptosporidiosis cases, 24 of which were from British Columbia, Canada, were characterized using nested polymerase chain reaction amplification of the polymorphic internal transcribed spacer 1 locus. Two predominant Cryptosporidium parvum genotypes were found. Twelve (8 sporadic and 4 outbreak) isolates amplified with the cry7/cry21 primer pair and 12 (5 sporadic and 7 outbreak) isolates amplified with the cry7/cryITS1 primer pair. Multi-locus gene analysis using sequence polymorphisms on 3 other loci, i.e., the thrombospondin-related adhesion protein gene, the dihydrofolate reductase gene, and the 18S rRNA gene on 8 (4 outbreak and 4 sporadic) isolates showed non-random association among the human and animal alleles of the 4 different C. parvum gene loci. Associations between these 2 parasite genotypes and different routes of cryptosporidiosis transmission such as zoonotic, anthroponotic, and waterborne transmission were studied using municipal population and agricultural information, as well as detection of C. parvum oocysts in municipal drinking water specimens of the residential communities of sporadic and outbreak cases.

Animals↗
PubMed1999

Glucose metabolism in vitro of cultured and transplanted mouse pancreatic islets microencapsulated by means of a high-voltage electrostatic field.

The aim of this study was to assess the function of mouse pancreatic islets microencapsulated using a high-voltage electrostatic field. Islets were microencapsulated in alginate/poly-L-lysine/alginate (APA) capsules and maintained in tissue culture. Rates of glucose oxidation and insulin release were then assessed. Glucose metabolism was also measured in microencapsulated islets retrieved after transplantation to normal syngeneic mice. The high-voltage electrostatic system made possible the production of uniformly sized microcapsules, which were smaller than those produced by co-axial air-jet systems. Nonencapsulated islets were used as controls. Empty microcapsules or islet-containing microcapsules were transplanted intraperitoneally and retrieved after 2 weeks for assessment of foreign-body reactions and glucose oxidation rates. After 1 day and 2 weeks in tissue culture, both control islets and microencapsulated islets increased their rates of glucose oxidation and insulin release 7- to 10-fold in response to an increase in glucose concentration from 1.7 to 16.7 mmol/l. Both empty and islet-containing microcapsules, retrieved 2 weeks after transplantation, showed high rates of glucose oxidation at both low and high glucose concentrations, suggesting overgrowth with metabolically active fibroblasts. Morphological studies indicated a marked foreign-body reaction on the surface of all transplanted microcapsules. The islets in cultured microcapsules had a normal histological appearance, whereas the islets within transplanted microcapsules showed a range of morphological appearances, from intact islets to cell debris. In conclusion, this study shows that mouse pancreatic islets survive and remain functionally competent for at least 2 weeks in vitro after microencapsulation in APA capsules generated in an electrostatic field. However, a foreign-body reaction with cellular growth on the capsular surface was present after intraperitoneal syngeneic transplantation.

Animals↗
PubMed1999

Denaturing gradient gel electrophoresis screening of the BRCA1 gene in cells from precancerous cervical lesions.

OBJECTIVE: To determine the integrity of the BRCA1 gene in archival, paraffin-embedded tissues from precancerous lesions of the uterine cervix. STUDY DESIGN: DNA was extracted from histologically documented precancerous cervical lesions (17 cases). Polymerase chain reactions were performed targeting exon 11 of BRCA1 (434-bp), the L1 consensus human papillomavirus (HPV) gene common to > 25 HPV types, as well as the beta-globin gene. The amplified products were analyzed using denaturing gradient gel electrophoresis. RESULTS: Mutation of the BRCA1 exon 11 gene was detected in > 76% of cases with precancerous lesions of the cervix. The mutations were either complete deletions or deletions of one or more nucleotides, leading to frame shifts. There were no significant differences in frequency of BRCA1 mutations among precancerous cervical tissues positive for the HPV L1 consensus gene (n = 9) when compared with HPV-negative tissues. CONCLUSION: The mutated BRCA1 gene was associated with 76% of 17 precancerous lesions of the cervix. The type of cervical intraepithelial neoplasia and the presence or absence of HPV were not related to the mutations. The role of BRCA1 mutation in the genesis of precancerous cervical lesions needs to be explored further.

DNA, Viral↗
PubMed1999

[T lymphocyte immunological response to different antigenic fractions of Mycobacterium bovis in juvenile chronic polyarthritis].

BACKGROUND: The possible relationship of stress or heat-shock proteins (hsp) with the pathogenesis of autoimmune disease has been intensely studied recently. In adult rheumatoid arthritis, a bacterial hsp (65 kDa hsp from Mycobacterium tuberculosis or bovis) would have a cross reactivity with a hsp of ARTICULAR cartilage. AIM: To assess the cellular immune response to the 65 kA hsp from M Bovis in children. PATIENTS AND METHODS: The proliferative response of peripheral mononuclear cells of 20 children with juvenile chronic polyarthritis and 20 healthy controls, against the 65 kDa hsp and other antigenic fractions from M bovis, was studied. RESULTS: Patients with juvenile chronic polyarthritis had a intense reaction against 65 kDa fraction and a second fraction located between 32.5 and 27.5 kDa. Patients with a prolonged evolution of the disease (more than five years), reacted preferentially to an antigenic segment located between 32.5 and 27.5 kDa and those with a shorter evolution did so with an antigen of 27.5-18.5 kDa. CONCLUSIONS: These results support the hypothesis that 65 kDa hsp from M bovis is involved in the pathogenesis of chronic juvenile polyarthritis and suggest that patients with short or prolonged evolutions of the disease would react to different antigenic fractions.

Adolescent↗
PubMed1999

Toward a standard of care for treating suicidal outpatients: a survey of social workers' beliefs about appropriate treatment behaviors.

This study attempts to establish what reasonable, prudent professionals, named in the standard of care, believe is appropriate treatment for suicidal outpatients. We hope to move toward establishing a standard of care based on actuarial data, rather than after the fact evaluation by experts, judges, and lawyers. Previously, Greaney (1995, doctoral dissertation, Pacific Graduate School, Palo Alto, CA) empirically examined the beliefs of psychologists in appropriately treating suicidal outpatients. Our goal is to broaden the perspective of existing empirical data by examining the beliefs of clinical social workers in treating suicidal outpatients.

Ambulatory Care↗
PubMed1998

Chromogranin B (secretogranin I), a neuroendocrine-regulated secretory protein, is sorted to exocrine secretory granules in transgenic mice.

Chromogranin B (CgB, secretogranin I) is a secretory granule matrix protein expressed in a wide variety of endocrine cells and neurons. Here we generated transgenic mice expressing CgB under the control of the human cytomegalovirus promoter. Northern and immunoblot analyses, in situ hybridization and immunocytochemistry revealed that the exocrine pancreas was the tissue with the highest level of ectopic CgB expression. Upon subcellular fractionation of the exocrine pancreas, the distribution of CgB in the various fractions was indistinguishable from that of amylase, an endogenous constituent of zymogen granules. Immunogold electron microscopy of pancreatic acinar cells showed co-localization of CgB with zymogens in Golgi cisternae, condensing vacuoles/immature granules and mature zymogen granules; the ratio of immunoreactivity of CgB to zymogens being highest in condensing vacuoles/immature granules. CgB isolated from zymogen granules of the pancreas of the transgenic mice aggregated in a mildly acidic (pH 5.5) milieu in vitro, suggesting that low pH-induced aggregation contributed to the observed concentration of CgB in condensing vacuoles. Our results show that a neuroendocrine-regulated secretory protein can be sorted to exocrine secretory granules in vivo, and imply that a key feature of CgB sorting in the trans-Golgi network of neuroendocrine cells, i.e. its aggregation-mediated concentration in the course of immature secretory granule formation, also occurs in exocrine cells although secretory protein sorting in these cells is thought to occur largely in the course of secretory granule maturation.

Animals↗
PubMed1998

Preclinical characterization of an anti-tat ribozyme for therapeutic application.

A hammerhead ribozyme retroviral construct, denoted RRz2, targeting the coding region of the human immunodeficiency virus type 1 (HIV-1) tat gene, has shown itself to be effective in a range of test systems. Inhibition of the replication of HIV-1 IIIB and primary drug-resistant strains in pooled transduced CEMT4 cells was consistently found to be more than 80% compared with the control-vector transduced cells, whereas a mutant RRz2 gave approximately 45% inhibition. A multiple HIV-1 passage assay showed the absence of emergence of mutations within the specific viral RNA ribozyme target sequences. This lack of generation of ribozyme "escape mutants" occurred despite the almost complete disappearance of a HIV-1 quasi-species in the testing virus. When RRz2 was tested in peripheral blood lymphocytes (PBLs) from HIV-1-infected patients, paired analysis showed that cell viability in the ribozyme-transduced HIV-1-infected PBLs was significantly higher than that in the vector-transduced cells. This difference in viability (vector versus RRz2) was not observed in PBLs from non-HIV-1-infected donors. Taken together, these results indicate that the transfer of an anti-HIV-1 ribozyme gene into human T lymphocytes could have major impact on viral replication and T cell viability in the HIV-1-infected individual.

Base Sequence↗
PubMed1998

The pufferfish SLP-1 gene, a new member of the SCL/TAL-1 family of transcription factors.

The SCL/TAL-1 gene encodes a basic helix-loop-helix (bHLH) transcription factor essential for the development of all hemopoietic lineages and also acts as a T-cell oncogene. Four related genes have been described in mammals (LYL-1, TAL-2, NSCL1, and NSCL2), all of which exhibit a high degree of sequence similarity to SCL/TAL-1 in the bHLH domain and two of which (LYL-1 and TAL-2) have also been implicated in the pathogenesis of T-cell acute lymphoblastic leukemia. In this study we describe the identification and characterization of a pufferfish gene termed SLP-1, which represents a new member of this gene family. The genomic structure and sequence of SLP-1 suggests that it forms a subfamily with SCL/TAL-1 and LYL-1 and is most closely related to SCL/TAL-1. However, unlike SCL/TAL-1, SLP-1 is widely expressed. Sequence analysis of a whole cosmid containing SLP-1 shows that SLP-1 is flanked upstream by a zinc finger gene and a fork-head-domain gene and downstream by a heme-oxygenase and a RING finger gene.

Amino Acid Sequence↗
PubMed1998

Flow cross-matching identifies patients at risk for postoperative elaboration of cytotoxic antibodies.

BACKGROUND: Cytotoxic IgG against class I antigens can contribute to renal dysfunction or failure after transplantation. However, the clinical relevance of IgG measured by flow cytometric cross-matching is controversial. This study correlated pre- and postoperative flow reactivity with clinical outcome among renal transplant patients with negative preoperative cytotoxic cross-matches. METHODS: Nonsensitized primary renal allograft patients (n = 157) with negative preoperative cytotoxic cross-matches (complement-dependent lymphocytotoxicity assays) were stratified on the basis of IgG reactivity measured by flow cytometric cross-matching (FCXM) as FCXM negative (Neg) or positive against class I (T-pos FCXM) or class II (B-pos FCXM) antigens. The groups were compared in terms of frequency of early rejection and 1-year graft survival. RESULTS: Patient distribution was 67% Neg, 14% T-pos FCXM, 14% B-pos FCXM, and 5% IgM FCXM. The incidence of early rejection was 25+/-3% for Neg and 51+/-3% for T- and B-pos FCXM (P < 0.05). One-year graft survival for Neg versus T-pos and B-pos FCXM was 97+/-3% versus 44+/-10% (P < 0.05) and 77+/-5% (P = 0.06), respectively. Rejections requiring plasmapheresis were found only among patients with T-pos FCXM. Among 29 patients, FCXM and complement-dependent lymphocytotoxicity assays were performed 10+/-2 and 28+/-4 days after transplantation. Pre- and posttransplant antibody levels were relatively unchanged among Neg and B-pos FCXM patient groups. In contrast, patients with T-pos FCXM produced cytotoxic IgG against class I after transplantation, which may have contributed to the severe graft dysfunction experienced by this group. CONCLUSIONS: FCXM is a useful tool to stratify primary renal transplant candidates in terms of potential risk for severe rejection. Furthermore, demonstration of preoperative flow reactivity against class I may identify a subgroup of patients at risk for early elaboration of cytotoxic alloantibody.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1998

Expression of CD3 epsilon, CD3 zeta, and RAG-1/RAG-2 in decidual CD56+ NK cells.

In early pregnancy the uterine mucosa, the decidua, is infiltrated by numerous CD56bright, CD16- natural killer (NK) cells. In this paper we have shown that unlike adult peripheral blood NK cells these uterine NK cells express cytoplasmic CD3 and CD3 zeta, but CD3 gamma and CD3 delta were not found in the majority of cells. In contrast to previous reports, there was no evidence of RAG-1 nor RAG-2 expression in decidual NK cells. These findings have implications for the ontogeny and development of decidual NK cells.

CD3 Complex↗
PubMed1998

Assessment of archived paraffin-embedded cervical condyloma tissues for mycoplasma-conserved DNA using sensitive PCR-ELISA.

Clinically, it is important to detect mycoplasmas because these organisms have been implicated in gastric and ovarian cancer, pneumonia, postabortal fever, pelvic inflammatory disease, pyelonephritis, endometritis, urethritis, perinatal mortality, arthritis, spontaneous abortion, infertility and interference with sperm development and they act as cofactors catalyzing the HIV disease state. Recently, the combined polymerase chain reaction and enzyme-linked immunosorbent assay method targeting the consensus DNA of over 15 species of mycoplasmas was shown to be superior for the detection of mycoplasmas. The objective was to determine if there was an association between mycoplasmas and cervical neoplasia. Cervical tissues, histopathologically categorized by cervical intraepithelial neoplasia (CIN) grade, flat or exophytic, and acanthosis or koilocytotic, were used. The results showed that mycoplasmas DNA were present in 21.4% of the condyloma tissues and in 33.3% of condyloma tissues with CIN. In contrast, mycoplasmas DNA were not detected when there were no CIN. The presence or absence of human papillomavirus (HPV) did not make a difference. Mycoplasmas DNA were present in 40.0 and 12.5% of the exophytic and flat condylomas, respectively. A higher percentage of cervical tissues graded with slight koilocytosis had (P = 0.05) mycoplasmas DNA compared with tissues graded with moderate koilocytosis. The detection of mycoplasmas DNA in archived cervical condyloma tissues with CIN corroborated previous reports of an association between mycoplasmas and CIN. However, the association between mycoplasmas and the presence of HPV could not be made in this study.

Condylomata Acuminata↗
PubMed1998

Enhanced fertility after heat-induced hyperactivation.

OBJECTIVE: To determine sperm hyperactivation, kinematic parameters, and fertilizing capacity after pretreating sperm at 40 degrees C for 4 hours. DESIGN: Prospective study involving pooled donor sperm that were colloid washed and incubated at either 23 degrees C (control) or 40 degrees C (heat-treated) for 4 hours as pretreatment. After incubation, analyses were performed with a computer-assisted sperm analyzer, whereas separate portions of sperm were evaluated with the sperm penetration assay at 37 degrees C. SETTING: Clinical and academic research environment. PATIENT(S): Cryopreserved-thawed sperm from different donors (n = 5). MAIN OUTCOME MEASURE(S): Sperm kinematic and fertilizing parameters. RESULT(S): Heat pretreatment of sperm resulted in over 22 times higher hyperactive motility at hour 4 compared with the control. The other kinematic parameters were also different. The heat-pretreated sperm group had a significantly higher percent penetration of zona-free oocytes with more swollen sperm heads per oocyte and enhanced sperm binding. CONCLUSION(S): The results showed that hyperactivation was induced by pretreatment of sperm with 40 degrees C heat, suggesting the involvement of heat factors in hyperactivation. The fertilizing capacity of sperm may be improved by the mild heat pretreatment when marked by the presence of heat-induced hyperactivation.

Female↗
PubMed1998

Ofloxacin: the next generation of antibiotic in sperm and embryo cultures for assisted reproductive technologies.

OBJECTIVE: To analyze the effect of different concentrations of ofloxacin on sperm kinematic parameters and to determine the embryotoxicity of ofloxacin at physiologic and at 100x concentrations. DESIGN: Prospective comparative study. SETTING: Clinical and academic research environment. PATIENT(S): Pooled cryopreserved donor sperm (n = 7). INTERVENTION(S): Human sperm were processed through two-layer discontinuous Percoll gradients, and the resultant pellet was resuspended in either HEPES-buffered human tubal fluid medium containing different concentrations of ofloxacin or the control medium. After measuring the kinematic parameters, the percentages of apoptosis and viability were obtained. Next, the sperm DNA was extracted and polymerase chain reaction of beta-globin gene was performed followed by denaturing gradient gel electrophoresis. Mouse embryos recovered at the one-cell pronuclear or zygote stages were cultured in the presence or absence of ofloxacin up to the hatched blastocyst stage and differences in development were recorded. MAIN OUTCOME MEASURE(S): Sperm kinematic parameters, sperm beta-globin gene, and number of embryos reaching the hatched blastocyst stage. RESULT(S): The number of embryos exposed to control and physiologic ofloxacin concentrations showed comparable excellent growth. However, the 100x concentration significantly arrested development. Rates of sperm viability and apoptosis measured 48 hours after exposure to the above concentrations were not different from controls. No differences were noted in the sperm kinematic parameters of sperm exposed to ofloxacin concentrations (1x, 10x, and 100x) or control medium after 0, 4, and 48 hours of incubation. Denaturing gradient gel electrophoresis of beta-globin genes from DNA exposed to varying ofloxacin concentrations failed to show any point mutations. CONCLUSION(S): Ofloxacin was embryotoxic at pharmacologic concentrations (100x). At physiologic or higher concentrations, ofloxacin appears to be safe and does not affect sperm kinematic parameters when compared with controls. This may indicate that sperm motility parameters alone cannot be relied on to evaluate the effects of drugs on fertility and that in vitro embryologic studies are essential. Ofloxacin at any concentration did not alter the rates of sperm apoptosis or viability. Ofloxacin does not appear to be mutagenic as evidenced by the beta-globin gene analysis.

Analysis of Variance↗
PubMed1998

A convenient mixed immunobeads screen for antisperm antibodies during routine semen analysis.

OBJECTIVE: To determine if leftover unused IgG, IgA, and IgM immunobeads could be combined as a convenient screen for antisperm antibodies in unwashed sperm. For comparisons, the mixed antiglobulin reaction (SpermMar) and immunobead test were performed. DESIGN: Prospective comparative study. SETTING: Clinical and academic research environment. SUBJECT(S): Donor human sperm negative for antisperm antibodies. INTERVENTION(S): Sperm specimens (n = 9) were equally divided and sera with antisperm antibodies added to one portion (positive control). MAIN OUTCOME MEASURE(S): Assessment of antisperm antibodies in sperm. RESULT(S): The mixed immunobeads screen qualitative results were the same for both the SpermMar and immunobead tests. The mixed immunobeads screen (positive when > or =10% motile sperm was bound) had a sensitivity and specificity of 100%. The percentages of bound sperm for the mixed immunobeads screen correlated with the SpermMar but not the immunobead test. The mixed immunobeads screen intraassay and interassay coefficients of variation were 28.9% and 45.6%, respectively. CONCLUSION(S): Matching results between the mixed immunobeads screen and the SpermMar or immunobead test suggested that the screen could be used to detect antisperm antibodies in unwashed sperm. There was no advantage to washing the sperm, although the screen was flexible and applicable for both unwashed and washed sperm.

Autoantibodies↗
PubMed1998

Multiple cases of acquired toxoplasmosis retinitis presenting in an outbreak.

OBJECTIVE: The purpose of the study was to examine the variability in presentation and outcome of individuals presenting with acquired toxoplasmosis retinitis in the setting of an outbreak of the disease. DESIGN: The study design was a case series. PARTICIPANTS: Twenty-one eyes of 20 patients with equal gender distribution and a mean age of 54 years followed for 38 to 170 weeks (mean 113.7 weeks) were studied. INTERVENTION: Systemic antimicrobials and corticosteroids when indicated were given. MAIN OUTCOME MEASURES: Visual acuity, media inflammation and clarity, resolution of active retinitis, and appearance of recurrence were observed. RESULTS: Fifteen of 21 lesions were active, and 7 of the total number of lesions fell within the macula-peripapillary region. Overall, vision improved with treatment except in cases of macular involvement (3 cases) and persistent vitritis (3 cases). Four recurrences have occurred to date. CONCLUSIONS: This is the largest reported outbreak of acquired toxoplasmosis retinitis occurring within a single outbreak. Twenty-one eyes of 20 patients presented with retinal lesions, and on average, those treated for active retinitis had improvement in vision.

Adolescent↗
PubMed1998

Positive intravenous line tip cultures as predictors of bacteraemia.

Intravenous line tip cultures provide valuable information when taken in conjunction with blood culture, but in practice are often performed in isolation. This retrospective study has evaluated: (1) the frequency of isolated line tip culture; and (2) whether the species of microorganism isolated from line tip culture, using the Maki semi-quantitative culture method, is predictive of bacteraemia. Of 2753 line tip culture episodes in 1659 patients between May 1993 and August 1995, 2230 were performed in isolation (81%). Evaluation of 792 positive line tip culture episodes in 654 patients where blood cultures were performed in the period from 48 h before, to 24 h after tip culture, identified 825 line tip isolates. Of these, 194 were associated with a blood culture positive for the same species. The rate of positive blood culture, according to species, ranged from 10-72%. The highest rate was seen for methicillin-susceptible Staphylococcus aureus where 70 of 97 line tip episodes (72%) were associated with positive blood culture. This compared with a rate of 17% for coagulase-negative staphylococci (P < 0.0001). Patients with line tip cultures positive for S. aureus should be considered to be at high risk of bacteraemia.

Bacteremia↗
PubMed1998

Heat-induced hyperactivation.

PURPOSE: The objectives of this study were (1) to determine the sperm hyperactivation and related kinematic parameters at 40 degrees C after using four sperm wash procedures and (2) to correlate the heat-induced hyperactivation data with cases of clinical pregnancies from either artificial insemination or standard in vitro fertilization (IVF). METHODS: Semen samples (n = 51) were collected by ejaculation, and semen analyses were carried out to determine the pretreatment data. Sperm kinematic measurements were performed using the Hamilton Thorn HTM-C computer-aided sperm analyzer. Hyperactivation was determined using the sort module on the HTM-C. Membrane integrity was assessed using the hypoosmotic sperm swelling procedure. Sperm morphology and acrosomal status were also determined using the Spermac stain. Each semen specimen was divided and processed through either the swim-up wash, the 1-h test-yolk buffer (TYB) wash, the 1 mg/ml pentoxifylline stimulant procedure, or the two-layer 90:47% gradient colloidal solution procedure. The washed sperm were incubated at 25 or at 40 degrees C for 4 hr. After incubation, kinematic parameters were assessed for the posttreatment data. Semen specimens were obtained on different occasions for artificial insemination or standard IVF. Data from intracytoplasmic sperm injection cases were not included to avoid confounding factors. Live births and/or pregnancies with fetal heart-beat examined by ultrasound were considered clinical pregnancies. RESULTS: Heat-induced hyperactive motility was significantly higher in sperm of the male partner of pregnant (n = 7) patients compared with nonpregnant (n = 44) patients (mean +/- SE, 10.0 +/- 3.3 versus 5.5 +/- 0.8%) after TYB processing followed by 4 hr of incubation at 40 degrees C. This was also observed after colloid (Percoll) processing (11.6 +/- 4.6 versus 5.8 +/- 0.8%). There were no differences in hyperactivation after 4 hr at 23 degrees C between pregnant and nonpregnant cases. Parameters such as count, volume, motility, viability, and acrosomal status were not different for the groups. However, the percentage of sperm with normal morphology (WHO classification) was twice as high in the pregnant group versus the nonpregnant group. CONCLUSIONS: Heat-induced hyperactivation was associated with fertile sperm and was predictive of pregnancy obtained after artificial insemination or IVF. The association was evident only after TYB or Percoll sperm processing. The study could not confirm the finding of significant decreases in motility after heat treatment of sperm derived from infertile males. The mechanism for heat-induced hyperactivation did not involve membrane integrity or the sperm acrosome, although an involvement of heat shock proteins was postulated. Interestingly, there were no pregnancies when sperm did not exhibit heat-induced hyperactivation.

Acrosome↗