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Biomedical subjects

J T Nielsen

Publications and source records attributed to J T Nielsen.

At least 19 recordsLinked to original sources
PubMed1999

Desulfovibrio zosterae sp. nov., a new sulfate reducer isolated from surface-sterilized roots of the seagrass Zostera marina.

A sulfate-reducing bacterium, designated strain lacT, was isolated from surface-sterilized roots of the benthic macrophyte Zostera marina. Cells were motile by means of a single polar flagellum. Strain lacT utilized lactate, pyruvate, malate, ethanol, L-alanine, fumarate, choline and fructose with sulfate as electron acceptor. In addition, fumarate, pyruvate and fructose were also degraded without an external electron acceptor. Sulfate could be substituted with thiosulfate, sulfite and elemental sulfur. Optimal growth was observed between 32.5 and 34.5 degrees C, at an NaCl concentration of 0.2 M and in a pH range between 6.8 and 7.3. The G + C content of the DNA was 42.7 +/- 0.2 mol%. Desulfoviridin and catalase were present. Strain lacT contained c-type cytochromes. Comparative 16S rRNA gene sequence analysis and the fatty acid pattern grouped this isolate into the genus Desulfovibrio. However, strain lacT differs from all other described Desulfovibrio species on the bases of its 16S rRNA gene sequence, the G + C content, its cellular lipid pattern and the utilization pattern of substrates. These characteristics establish strain lacT (= DSM 11974T) as a novel species of the genus Desulfovibrio, for which the name Desulfovibrio zosterae sp. nov. is proposed.

Base Composition↗
PubMed1996

[Study of children with urinary tract infections. Does intravenous urography play any role?].

Ninety children referred to hospital with urinary tract infections (UTI) were investigated by intravenous urography (IVU), ultrasonography (US) and 99m-Tc dimercaptosuccinic acid scan (DMSA). Fifty-eight children also had a micturition cystourethrography performed. In 36 (40%) of the children at least one result was abnormal. In 29 children IVU was abnormal, 10 had abnormal US and 16 had abnormal DMSA. Six of the 58 children had vesicoureteric reflux in eight kidneys. In 16 children IVU was the only examination with an abnormal result, and in ten of these the findings were considered important for treatment or prognosis. In conclusion, IVU is an important supplement to US and DMSA in investigation programs for children with UTI. IVU should be performed in cases of renal scarring or dilatation and in children with recurrent infections.

Chelating Agents↗
PubMed1996

Location of adrenal medullary pheochromocytoma by I-123 metaiodobenzylguanidine SPECT.

This is a retrospective study evaluating the efficacy of SPECT in the location of pheochromocytoma. Thirty patients with a suspected pheochromocytoma underwent I-123 metaiodobenzylguanidine (I-123 MIBG) SPECT 4 and 22 hours after intravenous injection of 370 MBq I-123 MIBG. SPECT was compared with planar scintigraphy, CT scanning, histology, and clinical course. Twenty-two-hour I-123 MIBG SPECT correctly identified 10 patients with adrenal medullary pheochromocytoma and correctly excluded pheochromocytoma in 19 patients. The sensitivity of the 22-hour MIBG SPECT was 1.00 and the specificity was 0.95. The positive predictive value was 0.95 and the negative predictive value was 1.00. In 16 patients, planar scintigraphy was compared with SPECT. SPECT located normal adrenal glands and tumors with greater confidence in three dimensions, but the patients with adrenal medullary pheochromocytoma were all correctly identified by planar scintigraphy. The results of SPECT and CT agreed in 29 of 30 patients (96.7%). I-123 MIBG SPECT for the location of pheochromocytoma has a high sensitivity, specificity, and positive and negative predictive values. I-123 MIBG SPECT or CT scanning alone were equally good for locating adrenal medullary pheochromocytoma but the combination of MIBG SPECT and CT makes it possible to distinguish between functioning and nonfunctioning adenomas. I-123 MIBG SPECT may be used alone or in combination with planar scintigraphy when three-dimensional location of a lesion is wanted.

3-Iodobenzylguanidine↗
PubMed1995

Pharmacokinetics and dosimetry of [111In] F(ab')2 fragments against prostatic acid phosphatase after intraprostatic injection for immunoscintigraphy in prostate cancer.

The purpose of this study was to investigate the pharmacokinetics and dosimetry of using [111In]-labelled F(ab')2 fragments against prostate acid phosphatase (FC-3001, Orion Corporation Farmos, Finland) for the detection of metastatic prostate cancer. Five patients in all were subjected to intraprostatic injection of 1 mg FC-3001 labelled with 85-100 MBq [111In]. In four of the patients the biodistribution was studied by sequential whole-body counting, gamma-camera scintigraphy of the abdomen in antero-posterior and postero-anterior projections. Blood and urine samples were collected sequentially up to 72 h after injection. Initially, significant amounts of antibody fragments were released from the site of injection. After the first 4 h, 22.0% of injected antibody (2.2-41.3% ID) remained in the prostate and was slowly released with a final half-life of 80.4 h (49.9-141.8 h). Labelled antibody appeared in the blood shortly after injection and was cleared from the blood with a final half-life of 27.7-300.9 h. The liver, the bone marrow and, in two patients, the kidneys accumulated antibody fragments in significant amounts during the period of investigation. An apparent relationship between the initial whole-body clearance and renal uptake is described. The effective dose averaged 0.37 mSv/MBq (range 0.24-0.52 mSv/MBq). The highest equivalent doses were received by the kidneys (0.46-2.81 mGy/MBq) the liver (0.44-1.59 mGy/MBq) and the bone marrow (0.37-0.57 mGy/MBq). Only in two of the patients with known metastases were pathological foci seen. The disappointing imaging results were probably caused by the biphasic release of antibody from the prostate, and indicates that intraprostatic injection of this antibody has no advantage for imaging, as well as being unpleasant for the patient. The biodistribution of the antibody following release from the prostate is similar to but more variable than the biodistribution seen in patients after intravenous injection of labelled antibodies.

Aged↗
PubMed1995

Diagnostic imaging in children with urinary tract infection: the role of intravenous urography.

Ninety children referred to hospital with urinary tract infection (UTI) were investigated by iv urography (IVU), ultrasonography (US) and 99mTc dimercaptosuccinic acid scan (DMSA). Fifty-eight children also underwent micturating cystourethrography (MCUG). In 36 (40%) of the children, at least one result was abnormal. Abnormal findings were found in 29 children with IVU, in 10 with US and in 16 with DMSA. Six of the 58 children had vesicoureteric reflux (VUR) in 8 kidneys. In 16 children, IVU was the only examination with an abnormal result, and in 10 of these the findings were considered important for treatment or prognosis. IVU is an important supplement to US and DMSA in investigation programs for children with UTI. IVU should be performed in cases of renal scars, dilatations or in children with recurrent infections.

Adolescent↗
PubMed1992

Detection of rhinorrhoea by cisternography in combination with single photon emission tomography, following lumbar injection of iodine-123-labelled albumin.

Eight patients were examined. Seven had verified rhinorrhoea and six had had one or more episodes of pneumococcal meningitis. In four of the patients a fistula could not be visualized by computed tomography. All eight patients had injections of iodine-123-labelled albumin by lumbar puncture. Tomoscintigraphy (SPET) was performed 3, 6 and 8-9 h after injection. After 6-8 h we were able to demonstrate a fistula in seven of the patients with verified rhinorrhoea and the findings were confirmed by a subsequent operation. In one of the patients we were not able to visualize any leak of cerebrospinal fluid into the nasal cavity. This patient was not operated upon and we were not able to verify the findings in this patient. The operated patients all did well after the operation with no relapse of meningitis. In conclusion, SPECT-cisternography after intralumbar injection of iodine-123-labelled albumin is a valuable diagnostic tool for the detection of small fistulae in patients with rhinorrhea.

Adult↗
PubMed1992

Renal handling of carboplatin.

The mechanism for renal handling of carboplatin was studied in 17 ovarian cancer patients treated with a combination of carboplatin and cyclophosphamide. Carboplatin and [51Cr]-ethylenediaminetetraacetic acid (EDTA) renal clearances were measured simultaneously during short intervals of from 45 to 120 min. A total of 131 clearance intervals were analyzed during 35 chemotherapy courses. The carboplatin/[51Cr]-EDTA clearance ratio (R) served as an indicator of the net tubular reabsorption (R less than 1) or secretion (R greater than 1). The R value was calculated for each sampling interval. No significant difference was found between interpatient and intertreatment variation. The intertreatment variation as tested against the variation in the short intervals by an F-test was highly significant. We calculated the average R value for each treatment and consequently based our results on a total of 35 observations. The mean R value was 0.77 (t-test for R = 1; P less than 0.001). We conclude that the renal elimination of carboplatin takes place by glomerular filtration followed by tubular reabsorption.

Adult↗
PubMed1992

Angiotensin-converting enzyme inhibitor renography in the diagnosis of renovascular hypertension. Studies before and after angioplasty.

Renography with [99mTc] diethylenetriaminepenta-acetate (DTPA) was performed in 26 patients with renal artery stenosis (RAS), unilateral in 15 and bilateral in 11, and in 16 patients with essential hypertension with a normal renal angiogram. Nine of the patients with unilateral RAS were restudied after a successful percutaneous transluminal renal angioplasty (PTRA), i.e. complete removal of the stenosis and a normalization of the blood pressure without antihypertensive treatment. Single-kidney [99mTc]-DTPA clearance and parenchymal mean transit time (MTT) were determined at each examination. All patients were studied on two different days using the same procedure except that captopril 25 mg was given orally before renography at the second examination. In unilateral RAS captopril reduced single-kidney [99mTc]-DTPA clearance significantly on the affected side (-42.7%, median) but not on the unaffected side (-3.2%). In bilateral RAS single-kidney [99mTc]-DTPA clearance was reduced to the greatest extent on the most affected side (-43.0%) compared with the least affected side (-17.2%). In essential hypertension no significant changes were recorded on any side (-1.5% for both). After PTRA, single-kidney [99mTc]-DTPA clearance was not significantly changed by captopril either on the previously affected side (4.3%) or on the unaffected side. MTT was significantly prolonged after captopril on the affected side in unilateral RAS and on the most affected side in bilateral RAS, whereas no significant changes were found on the unaffected side in unilateral RAS, on the least affected side in bilateral RAS, or on any side in essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

New evidence for trans-species evolution of the H-2 class I polymorphism.

A serological survey using alloantisera specific for the H-2 class I antigens in Japanese wild mice. Mus musculus molossinus, revealed a high frequency of the H-2Kf antigen. This antigen has also been found in European wild mice, M. m. domesticus and M. m. musculus. In this survey, the H-2Kf antigen was characterized through the use of ten newly isolated monoclonal antibodies raised against cells of a Japanese wild mouse, and by Southern blot analysis using an H-2K locus-specific probe which hybridizes with the 3' end of the gene. The serologically identified H-2Kf antigens revealed several minor variations in reactivities to the monoclonal antibodies. However, all the antigens examined could be clearly separated into two types with respect to the restriction fragment length polymorphism (RFLP) pattern. The first type, found together with a single, characteristic RFLP pattern, was always associated with the presence of reactivity to one particular monoclonal antibody MS54. The second type, found to represent different RFLP patterns, is associated with the absence of reactivity to MS54. This concordance between the presence of an antigenic determinant and a particular RFLP was observed not only within Mus musculus subspecies but also in a different species: M. spretus, carrying the same antigenic determinant, gave an identical RFLP to that of the other MS54-positive Mus musculus subspecies. The data suggest that the antigenic determinant specific for MS54 is an ancient polymorphic structure which has survived the long period of diversification of Mus species (approximately 2-3 million years) without alteration, and is associated with a stable DNA structure at the 3' end of the H-2K gene.

Animals↗
PubMed1988

Influence of flow rate and perfused load on insulin absorption in isolated proximal tubules.

The effect of flow rate and perfused load on insulin absorption was studied in isolated proximal rabbit tubules. In one series of experiments tubules were perfused for 30 min with 125I-[A14]insulin at 3.6 ng/ml and at flow rates varying between 2.2 and 43.3 nl/min, thus varying both flow rate and the perfused load. In a second series of experiments the tubules were exposed to increasing loads of insulin at a fixed flow rate of 15 nl/min. In a third series of experiments two groups of tubules were exposed to identical perfused loads at two different flow rates. The results showed that absorption is linearly correlated with the perfused load in the ranges of flow rates and concentrations examined. The perfused load determined the magnitude by which the insulin was reabsorbed, whereas the flow rate determined the efficiency (fractional absorption) by which the protein was reabsorbed. At flow rates less than 5 nl/min the fractional absorption was greater than 65%, and at flow rates greater than 30 nl/min fractional absorption was less than 40%. Thus, there is an inverse relationship between flow rate and fractional absorption. The described effects of changes in flow rate and perfused load are suggested to be caused by concomitant changes in the mean luminal concentration.

Absorption↗
PubMed1987

Luminal and basolateral uptake of insulin in isolated, perfused, proximal tubules.

The present study was performed to quantitate and compare the luminal and the peritubular uptake of 125I-labeled insulin in isolated, perfused, proximal tubules from rabbit kidneys. 125I-insulin was added in physiological concentrations of 3.0-7.0 ng/ml or 59.0-89.5 ng/ml (high insulin concentrations) to either the perfusate or the bath fluid for 30 min. The luminal uptake in 30 min averaged 0.76 pg/mm at physiological concentrations and 18.0 pg/mm at high insulin concentrations. About 15-41% of the absorbed insulin was digested and less than 5% was transported from the lumen to the peritubular space as intact insulin. The peritubular binding/uptake of 125I-insulin at physiological and high concentrations in the bath was 0.136 and 0.318 pg, respectively. Addition of excess unlabeled insulin (10(-5) M) to the bath produced significant inhibition of binding (53.7%) at 7.0 ng/ml, but no inhibition at 89.5 ng/ml labeled insulin in the bath. This indicates that insulin is bound/absorbed at the basolateral membranes both by a saturable specific mechanism and a nonspecific, nonsaturable mechanism. The basolateral absorption constituted 15.2 and 1.8% of the total tubular extraction of insulin at physiological and high insulin concentrations, respectively. Electron microscope autoradiography showed that, after luminal as well as basolateral endocytosis, insulin was exclusively accumulated in endocytic vacuoles and lysosomes.

Animals↗
PubMed1986

Coordination of murine parotid secretory protein and salivary amylase expression.

PSP, parotid secretory protein, and salivary amylase are the major secretory proteins of mouse parotid gland where they appear in a constant ratio. Here we describe the isolation of the PSP gene and show through expression analysis on this and the salivary amylase gene that the two genes are transcribed in a coordinate fashion in adult animals, whereas the activation profiles are different during postnatal development. An explanation is put forward that involves activation of the genes at different stages of the acinar cell differentiation, leading in adults to the maximal and thus proportionate expression.

Amylases↗