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Biomedical subjects

K Nielsen

Publications and source records attributed to K Nielsen.

At least 127 records · Page 7Linked to original sources
PubMed1996

A search for persistent rubella virus infection in persons with chronic symptoms after rubella and rubella immunization and in patients with juvenile rheumatoid arthritis.

Peripheral blood polymorphonuclear leukocytes, mononuclear cells, and plasma and nasopharyngeal specimens were obtained from 6 subjects with persistent symptoms following rubella immunization, 1 subject with persistent symptoms following rubella, 11 children with juvenile rheumatoid arthritis, 17 recently immunized control subjects, and 1 control subject with acute clinical rubella. Rubella virus was isolated from the blood or nasopharynx of four of the 18 control subjects. In contrast, rubella virus was not recovered from any specimens from the seven subjects with persistent symptoms following immunization or natural infection or from the 11 children with juvenile rheumatoid arthritis. A polymerase chain reaction assay detected rubella virus in the blood from three of 14 control subjects but not in the blood from two subjects with persistent symptoms following rubella immunization or in that from three children with juvenile rheumatoid arthritis. We have not been able to confirm the findings of others who have reportedly recovered rubella virus from lymphocytes of persons with persistent symptoms following rubella or rubella immunization.

Adolescent↗
PubMed1996

Presence of human immunodeficiency virus (HIV) type 1 and HIV-1-specific antibodies in cervicovaginal secretions of infected mothers and in the gastric aspirates of their infants.

The presence of human immunodeficiency virus (HIV) in cervicovaginal secretions (CVS) may be a risk factor for perinatal transmission. CVS of 25 women were evaluated for HIV and HIV mucosal antibodies; 16 infants had gastric aspirates cultured. Maternal plasma HIV was measured by quantitative RNA polymerase chain reaction. Seven women (28%), 4 of 19 pregnant and 3 of 7 nonpregnant, had HIV in CVS. Two of 4 HIV-infected neonates had positive gastric aspirate cultures. The 4 pregnant women with HIV in CVS did not transmit infection. HIV-specific secretory IgA was present in CVS of 10 (42%) of 24 women (in 3 cases concurrent with virus). Plasma HIV RNA levels at delivery were higher among transmitters (mean, 68,921 copies/mL) than nontransmitters (mean, 9457 copies/mL). Intermittent HIV shedding in CVS occurred despite mucosal antibodies and did not necessarily correlate with maternal plasma HIV RNA copy number. The presence of HIV in newborn gastric aspirates may be a risk factor for perinatal infection.

Cervix Uteri↗
PubMed1996

Systemic treatment in the rat with epidermal growth factor causes polycystic growth of the ovaries.

BACKGROUND: It has previously been suggested that epidermal growth factor (EGF) plays a role in the function of the ovary. We administered systemic EGF to assess the influence of EGF receptor stimulation on the morphology of the ovaries. METHODS: Forty-eight female Wistar rats were allocated to five groups receiving EGF treatment (150 microgram/kg/day) for 0 (controls), 1, 2, 3 and 4 weeks. All rats were exactly 8 weeks at the start of the experiment and 12 weeks at sacrifice. The EGF was administered in the weeks prior to sacrifice. At sacrifice, the perfusion-fixed ovaries were removed and weighed, and the volumes of tissue components were quantified using stereology. RESULTS: EGF administration increased the total weight of the ovaries from 129 +/- 18 mg in the controls to 158 +/- 29 mg (p<0.05) after one week. In subsequent weeks the total weight increased to 230 +/- 73 mg (p<0.001). The weight gain after one week of treatment was exclusively due to a fourfold increase in follicular cyst volume (p<0.01). In subsequent weeks the cyst volume was increased up to eightfold. After 2, 3 and 4 weeks of treatment the quantity of luteinizing cells was likewise increased by 70% (p<0.01). CONCLUSION: EGF administration causes the follicular cells to produce cysts and increases the quantity of luteinizing cells.

Animals↗
PubMed1996

Enhancement of respiratory immunity to Pasteurella multocida by cholera toxin in rabbits.

Cholera toxin (CT) is a potent adjuvant for the mucosal immune system. The purpose of this study was to determine if coadministration of CT with a potassium thiocyanate extract of Pasteurella multocida (PTE) leads to enhanced anti-PTE antibody activity and increased protection of rabbits against infection with P. multocida and associated disease. Groups of rabbits were immunized intranasally on days 0, 7, and 14, with phosphate buffered saline (PBS), 200 micrograms of CT, 1.0 mg of PTE, or 1.0 mg PTE with 200 micrograms CT. Nasal lavage and serum samples were collected over 28 days after initial immunization and evaluated by ELISA for specific antibody directed against PTE. Marked increases in serum (IgG) and nasal lavage (IgA) anti-PTE antibody activity were found beginning after day 14 in rabbits immunized with PTE. Rabbits immunized with PTE and CT demonstrated further increases in this activity. Tracheobronchial lavage samples collected at the time of necropsy demonstrated a significant level of anti-PTE IgA activity in animals immunized with PTE, and coadministration with CT stimulated a further significant increase in this activity. Groups of similarly immunized rabbits were challenged 16 days after initial immunization with 5 x 10(7) CFUs of P. multocida. Nasal lavage samples were cultured for P. multocida over the next 10 days. Rabbits were euthanized within 10 days after challenge, tissues cultured for P. multocida, and histopathologic lesion severity graded using a numeric scale. Rabbits immunized with PTE survived longer, had less severe lesions of the lungs, pleura, and liver, and fewer P. multocida CFUs cultured from samples than PBS or CT controls. Coadministration of CT led to further reductions in lesion severity of those tissues and numbers of P. multocida CFUs cultured from samples. Increased nasal turbinate atrophy of rabbits immunized with PTE with or without CT was associated with increased mean survival time. In summary, coadministration of CT with PTE enhanced protective immunity to P. multocida disease and infection in rabbits.

Adjuvants, Immunologic↗
PubMed1995

The reliability of preconization diagnostic evaluation in patients with cervical intraepithelial neoplasia and microinvasive carcinoma.

The accuracy of preconization cytology and histology was evaluated in 536 patients undergoing combination laser conization. Exact agreement between cytology and cone diagnosis was observed in 41.8% of the patients. The lowest agreement, 13.6% was demonstrated in cytologic cervical intraepithelial neoplasia (CIN) I, the highest in cytologic CIN III, 64.3%. Concerning microinvasive disease, the positive predictive value of cytology was only 27.3%; the negative predictive value 94.6%. When cytology showed CIN II or worse, the cone biopsy showed CIN or invasive disease in 92.8%. Exact agreement between preconization histology and the cone biopsy was found in 59.5%. Highest agreement was observed in CIN III lesions, 67.1%, and the lowest agreement in CIN II lesions, 42.7%. When preconization showed CIN II, a higher grade of lesion was found in the cone biopsy in 29.1%. Cone biopsy revealed invasive disease in 38 cases. In 24 cases, invasive disease was not demonstrated prior to conization, corresponding totally to 4.7% of patients not suspected to have invasive disease prior to conization. Regarding invasive disease, the sensitivity of preconization histology was 36.8%, the positive predictive value 58.3%, and the negative predictive value 95.3%. Kappa statistics demonstrated rather low agreement between cone diagnoses and preconization diagnoses. These results confirm the potential risk of overlooking invasive disease by conventional preconization evaluation and demonstrate the need for excisional methods in the management of cervical intraepithelial neoplasia to provide a sufficient specimen for diagnostic purposes. Combined with the therapeutic results, combination laser conization was a reliable diagnostic and therapeutic method in the management of patients with CIN and microinvasive cancer of the cervix.

Conization↗
PubMed1995

Serological crossreactivity between Brucella abortus and Yersinia enterocolitica 0:9 II the use of Yersinia outer proteins for the specific detection of Yersinia enterocolitica infections in ruminants.

Yersinia outer protein (YOP) preparations from Y. enterocolitica and Y. pseudotuberculosis were used as antigens in immunoblots for the detection of Yersinia infections in experimentally and naturally infected ruminants. Sera from 9 groups of animals were used: (1) 51 sera from cattle which were false-positive in the standard brucellosis serological tests, (2) 52 sera from brucellosis-negative cattle, (3) 51 sera from a deer herd in which 16 animals were positive in the brucellosis tests and Yersina species were isolated from 5 animals, (4) 50 sera from a deer herd in which sera from all animals were negative in the brucellosis tests, (5) 107 sera from brucellosis-negative cattle which were received from throughout New Zealand, (6) 30 sera from cattle naturally infected with B. abortus and from which B. abortus was isolated, (7) 55 sera from cattle naturally infected with B. abortus, (8) 26 sera from cattle experimentally infected with B. abortus, with mostly high titres in the conventional brucellosis tests, and (9) sera taken weekly from 3 cattle experimentally infected with Y. enterocolitica 0:9. In all 3 Y. enterocolitica 0:9 experimentally infected animals the antibody reactivity against major YOPs in the Y. enterocolitica and in the Y. pseudotuberculosis YOP preparation correlated well with the strength in the classical brucellosis tests and with the staining of smooth lipopolysaccharides (SLPS) in blots, thus confirming the usefulness of YOPs for the detection of Yersinia infections. Sera from naturally infected cattle and deer herds, regardless of whether they were false positive or negative in the brucellosis tests, showed high frequencies of staining in YOP blots (53-58% in cattle and 80-100% in deer), indicating a high prevalence of field infections with Yersinia species in New Zealand. In two of the three sera groups from B. abortus infected animals, antibodies against YOPs were detected with high frequency, showing that dual infections may be common and may interfere with differential serological testing.

Animals↗
PubMed1995

Long-term oral refeeding of patients with cirrhosis of the liver.

A previous study has shown that malnourished, clinically stable patients with liver cirrhosis are in protein and energy balance at their spontaneous dietary intake and that an improvement in nutritional status cannot be anticipated at this intake (Nielsen et al. 1993). In the present study we examined to what extent oral intake could be increased by nutritional support, and to what extent dietary protein would be retained with increased intake. The techniques used for balance studies were also validated since this information is not available for patients with liver cirrhosis. Fifteen malnourished patients with alcoholic liver cirrhosis were given increasing amounts of a balanced ordinary diet for 38 (SE 3) d. Intakes of protein and energy were recorded by weighing servings and leftovers on food trays. Protein intake was calculated from food tables. Total N disposal was calculated after measurement of urinary N excretion, and protein balance was calculated from the N balance. A validation study of protein balance in a subgroup of patients (analysis of N in food by the duplicate portion technique, correction for incomplete recovery of urine by measurement of urinary para-aminobenzoic acid (PABA) after administration of PABA tablets, and measurement of faecal N) did not change protein balance values. Protein intake increased from 1.0 (SE 0.1) g/kg per d to 1.8 (SE 0.1) g/kg per d. With increasing protein intake, 84 (SE 8)% of the increase in intake was retained. The rate of protein retention was not saturated at the intakes obtained in this study. Protein intolerance was only encountered in one patient. Available evidence indicates that the requirement for achieving N balance is increased in these patients but protein retention is highly efficient with increased intake. Protein retention is dependent on energy balance. Energy intake was calculated from food tables and total energy expenditure was calculated by the factorial method. A validation study was performed in a subgroup of patients. The energy contents of food sampled by the duplicate portion technique, and of urine and faeces were measured by bomb calorimetry. Resting energy expenditure (REE) was measured by indirect calorimetry before and at the end of the study, and O2 uptake during bicycle exercise was measured before and at the end of the study. The measured intake of metabolizable energy was on average 13% lower than the value given in food tables. Calculated energy expenditure was not changed by the validation study.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary Proteins↗
PubMed1995

Stability of freeze dried horseradish peroxidase conjugated monoclonal antibodies used in diagnostic serology.

Two murine monoclonal antibodies, an IgG1 isotype specific for the heavy chain of bovine IgG1, the second an IgG3 isotype and specific for an epitope of the O-polysaccharide of Brucella abortus were conjugated with horseradish peroxidase. The conjugated antibodies were freeze dried in the presence of a number of additives to preserve activity and tested for stability over an 18 month period. Addition of 0.3M trehalose or 0.8% lactalbumin and 3.2% sucrose resulted in the lowest loss of activity if the conjugated antibodies were freeze dried in glass vials. Freeze drying in polypropylene vials resulted in a more rapid rate of deterioration with some additives or an accelerated rate of decline after an initial plateau of lesser loss of activity. The use of polypropylene vials and lactalbumin and sucrose were included in this study because of their low cost compared to glass vials and trehalose. While each antibody behaved differently, addition of trehalose or lactalbumin and sucrose to the conjugated antibodies aided in the preservation of enzyme activity. Both additives provide a suitable method for long term storage of freeze dried or freeze dried and reconstituted monoclonal antibody-enzyme conjugates.

Animals↗
PubMed1995

Correlation of clinical progression in human immunodeficiency virus-infected children with in vitro zidovudine resistance measured by a direct quantitative peripheral blood lymphocyte assay.

A rapid method for determination of zidovudine resistance was developed and results were correlated with clinical outcome in human immunodeficiency virus (HIV)-infected children. The zidovudine susceptibilities of HIV-1 isolates from 34 children were determined through a direct quantitative peripheral blood lymphocyte assay and compared with results of the AIDS Clinical Trials Group resistance assay. Patients' peripheral blood lymphocytes were 5-fold diluted and cocultured with donor lymphocytes and varying concentrations of zidovudine. Isolates were defined as sensitive if inhibited by < or = 1.0 microM zidovudine and resistant at > 1.0 microM. Children (n = 21) with zidovudine-resistant virus had greater evidence of disease progression than did those with zidovudine-sensitive virus (n = 11) as demonstrated by failure to thrive (57% vs. 9%, P = .01) and opportunistic infections (48% vs. 0, P = .006). This assay may be useful as a screening tool for development of clinically relevant zidovudine resistance.

Child↗
PubMed1995

Evaluation of an indirect ELISA for the diagnosis of bovine brucellosis.

Control and eradication of bovine brucellosis is usually based on the serological detection of antibodies. In Argentina, the rose bengal test (RB) and the buffered plate antigen test (BPA) are the 2 screening tests officially recognized, whereas the 2-mercaptoethanol test (2ME) and the tube agglutination test (SAT) are the confirmatory assays currently in use. In order to improve the serological diagnosis of bovine brucellosis in Patagonia, Argentina, an indirect enzyme-linked immunosorbent assay (I-ELISA) kit distributed by the International Atomic Energy Agency was evaluated. Sera from negative nonvaccinated, negative but vaccinated, and positive animals were tested by all the above techniques. The specificity of the I-ELISA (98.9% and 97.2%) was similar to that of the BPA, RB, 2ME and complement fixation (CF) tests when used to test sera from negative nonvaccinated and negative but vaccinated animals, respectively. The sensitivity of the I-ELISA (98.7%) was higher than the BPA test (96.1%) and the CF test (95.2%). The I-ELISA kit evaluated in this study was thought to be a valuable tool for the diagnosis of bovine brucellosis in the Patagonia region where little epidemiological information is available about this disease, and where large numbers of sera should be tested to obtain such information.

Agglutination Tests↗
PubMed1995

The in vitro growth and serial passage of RA 27/3 rubella vaccine virus in cord blood mononuclear leukocytes from normal babies.

Because of our inability to isolate rubella virus from peripheral blood lymphocytes from patients with chronic symptoms after rubella immunization we performed a series of experiments with cord blood mononuclear cells (CBL) to determine whether and to what extent these cells supported the growth of rubella virus in vitro. CBL were stimulated with phytohemagglutinin for 48-72 h, washed, and inoculated with 1000 tissue culture 50% infection dose of rubella virus and placed in RPMI 1640 medium with 10% fetal bovine serum and IL-2. Approximately every 9 d the volume was halved, and new CBL were added. Aliquots at 2- to 9-d intervals were obtained and quantitatively cultured in African green monkey tissue culture. Rubella virus growth was determined by echovirus 11 challenge. Controls consisted of rubella virus in RPMI 1640 medium. Rubella virus persisted in CBL culture longer than in control medium in seven of 11 experiments, and in three instances there was evidence of productive infection.

Animals↗
PubMed1995

Protective immunity to Pasteurella multocida heat-labile toxin by intranasal immunization in rabbits.

Heat-labile Pasteurella multocida toxin (PMT) is an important virulence factor of some isolates from rabbits. To determine whether protective immunity to PMT could be induced in rabbits by intranasal immunization with heat-inactivated PMT, we immunized groups of rabbits intranasally at days 0, 7, 14, and 21 with inactivated PMT, with or without cholera toxin, an adjuvant for the mucosal immune system. Significant increases in anti-PMT IgA in nasal lavage samples and anti-PMT serum IgG, as determined by enzyme-linked immunosorbent assay, developed within 2 weeks after initial immunization. Coadministration of cholera toxin with inactivated PMT enhanced anti-PMT activity in the samples. Rabbits similarly immunized on days 0, 7, and 14 were challenged with PMT, and tissues were graded histologically on a numeric scale of lesion severity. Immunization conferred partial protection against development of pneumonia, pleuritis, hepatic necrosis, and testicular atrophy in rabbits challenged 16 days after initial immunization. Thus, immunization with inactivated PMT stimulates a protective response to PMT challenge in rabbits that is enhanced by coadministration of cholera toxin.

Administration, Intranasal↗
PubMed1994

A search for persistent measles, mumps, and rubella vaccine virus in children with human immunodeficiency virus type 1 infection.

OBJECTIVE: To determine whether live measles, mumps, and rubella vaccine viruses persist after immunization of immunocompromised children with human immunodeficiency virus type 1 infection. METHODS: Ten children with symptomatic human immunodeficiency virus type 1 infection who received measles, mumps, and rubella immunizations were studied. Peripheral blood mononuclear cells, polymorphonuclear leukocytes, and plasma were cocultivated with primary African green monkey kidney tissue culture cells for detection of measles, mumps, and rubella viruses. Antibody to measles and mumps was determined by indirect fluorescent antibody and rubella was determined by enzyme-linked immunosorbent assay. Children seronegative to measles were revaccinated. RESULTS: Neither measles, mumps, nor rubella virus was recovered from peripheral blood mononuclear cells, polymorphonuclear leukocytes, or plasma in these children. No child experienced symptoms thought to be related to the vaccines. Humoral immunity after one or two immunizations was detected in 33% of the children. After vaccination, two of 10 children had IgG to measles; four of 10, to mumps; and four of 10, to rubella. CONCLUSIONS: In spite of an impaired humoral immune response, persistent viremia or infection did not occur after immunization with attenuated measles, mumps, and rubella vaccine viruses. These findings suggest that immunologic response to these viruses was sufficient to prevent persistent infection in these children immunocompromised by human immunodeficiency virus type 1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Laser conization: the results of treatment of cervical intraepithelial neoplasia.

Combination laser conization was performed for the treatment of cervical intraepithelial neoplasia (CIN) in 473 patients, who were followed for a mean period of 70 months. In 16 cases (3.4%) CIN was demonstrated during follow up, and in 10 cases (2.1%) within the first year after treatment. The grade of CIN in the cone specimen was of no predictive value to recurrence. When excisional margins were involved recurrence was observed in 8.7% of cases, compared to 2.3% when margins were uninvolved. The risk of recurrence was significantly higher in patients with involvement of the endocervical cone margin. The only case of invasive disease during follow-up was observed more than 2 years after conization; cone biopsy was without involved margins. The results clearly demonstrate the method to be effective and justify an expectant management of all patients after conization by this method.

Adult↗
PubMed1994

The use of divalent cation chelating agents (EDTA/EGTA) to reduce non-specific serum protein interaction in enzyme immunoassay.

An indirect enzyme immunoassay (ELISA) for detection of bovine antibody to Brucella abortus was modified by the addition of divalent chelating agents to the serum diluent. This addition resulted in an increase in specificity from 96.0% in the regular assay to 99.4% in the modified procedure. Of the 15,715 sera initially tested by the indirect ELISA, 691 that had given positive reactions were selected for retesting in the indirect ELISA with EDTA/EGTA added. The buffered plate antigen test (BPAT) correctly identified 98.6% of the samples as negative. The addition of chelating agents did not alter the sensitivity of the indirect ELISA, which correctly classified 609 sera from animals from which B. abortus had been isolated as positive. The sensitivity of the BPAT was 97.8%.

Agglutination Tests↗
PubMed1994

Anti-idiotypic antibodies generated by sequential immunization detect the shared idiotype on antibodies to pseudorabies virus antigens.

Anti-idiotypic antibodies (anti-Id or Ab2) were generated in Balb/c mice against either mouse monoclonal or swine polyclonal antibodies (Ab1) to pseudorabies virus (PRV) antigens by conventional and sequential immunization methods. In the conventional method, one antibody preparation was repeatedly injected into the animals, whereas three anti-PRV antibody preparations were used alternately for the sequential immunization procedure. Anti-Ids were serologically characterized for possession of the Ab2s that detect shared idiotype (IdX) on antibodies to PRV antigens. Only the Ab2s that were generated by the sequential immunization method recognized the IdX present on murine and swine antibodies to PRV. The sequential immunization method described herein was anticipated to be helpful for generating virus specific Ab2s as candidates for serodiagnostic reagents or vaccines.

Animals↗
PubMed1994

Casein and soya-bean protein have different effects on whole body protein turnover at the same nitrogen balance.

The present study examined whether different proteins have different effects on whole-body protein turnover in adult rats. The rats were either starved, given a protein-free but energy-sufficient diet (1 MJ/kg body weight (BW) per d) or a diet containing intact casein, hydrolysed casein, or hydrolysed soya-bean protein at a level of 9.1 g/kg BW per d. The diets, which were isoenergetic with the same carbohydrate: fat ratio, were given as a continuous intragastric infusion for at least 4 d. During the last 19 h 15N-glycine (a primed continuous infusion) was given intragastrically and 15N was recovered from urinary ammonia and urea during isotope steady state for measurement of protein synthesis and protein degradation. Compared with starvation the protein-free diet decreased N excretion by 75%, probably by increasing the rate of reutilization of amino acids from endogenous proteins for protein synthesis. The protein diets produced a positive N balance which was independent of the protein source. Intact and hydrolysed casein increased protein synthesis 2.6- and 2.0-fold respectively, compared with the protein-free diet. Protein degradation increased 1.4- and 1.2-fold respectively. Hydrolysed soya-bean protein did not increase protein synthesis but decreased protein degradation by 35% compared with the protein-free diet. Compared with the hydrolysed soya-bean protein, intact casein resulted in 2.2- and 2.8-fold higher rates of protein synthesis and degradation respectively. These results are not easily explained by known sources of misinterpretation associated with the 15N-glycine method. Hydrolysed casein and hydrolysed soya-bean protein produced similar concentrations of insulin-like growth factor-1, insulin, glucagon, and corticosterone. The difference in amino acid composition between the dietary proteins was reflected in plasma amino acid composition and this is suggested to be responsible for the different effect on protein turnover. Preliminary results from this study have previously been published in abstract form (Nielsen et al. 1991).

Amino Acids↗