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Biomedical subjects

J Strauss

Publications and source records attributed to J Strauss.

At least 37 records · Page 2Linked to original sources
PubMed2000

Diuretic MAG3 scintirenography in children with HIV nephropathy: diffuse parenchymal dysfunction.

UNLABELLED: HIV nephropathy (HIVN) is prevalent in 15%-56% of HIV-infected children and induces mild to severe progressive nephropathy. METHODS: A total of 33 renal diuretic scintirenographic studies with 99mTc-mercaptoacetyltriglycine (MAG3) were reviewed and analyzed from 23 HIV pediatric patients, 21 of whom had HIVN with varying degrees of renal impairment. Results were compared with 10 studies of control patients of matching ages. Visual interpretation of images and renograms as well as semiquantitative analyses were performed. Variables compared were size of kidneys, time of peak and one-half peak activities, residual (or retained) cortical activity at 20 min, ratio of cortical activity at 2.5-20 min, and ratio of kidney activity to kidney plus background activity at 2 min. The results of MAG3 renal studies were also compared with laboratory data pertaining to creatinine clearance in all patients and with sonography in 17 patients. RESULTS: In most patients with HIVN (18/21), the kidneys were larger than normal, with a diffuse parenchymal dysfunction (decreased uptake, slow processing, and increased retention of activity) and flat renograms, findings similar to those observed in other diffuse parenchymal diseases. In all patients with HIVN, semiquantitative analysis (paired t test) showed statistically significant differences from control patients for all variables. On ANOVA, a statistically significant correlation was found between most scintigraphic parameters and the severity of renal impairment. Of the 17 concurrent sonographic studies in HIVN patients, 7 showed no abnormalities, whereas the results of scintigraphy were abnormal. CONCLUSION: Diuretic MAG3 scintirenography shows nonspecific diffuse parenchymal dysfunction in pediatric patients with HIVN. Such dysfunction may provide corroborative evidence of HIVN and should be recognized when the test is performed for standard indications. Further work is necessary to prove that the test has indeed the high sensitivity and good correlation with the seventy of HIVN suggested in this population; the test may be useful to follow up the progression of disease and the effect of treatment.

AIDS-Associated Nephropathy↗
PubMed2000

Diuretic MAG3 scintigraphy (F0) in acute pyelonephritis: regional parenchymal dysfunction and comparison with DMSA.

UNLABELLED: 99mTc-DMSA late static planar imaging or SPECT is being used for the investigation of focal acute pyelonephritis (APN), especially in children with urinary tract infection (UTI). Diuretic 99mTc-mercaptoacetyltriglycine (MAG3) dynamic scintirenography has been applied in the evaluation of kidney function and structure, frequently to exclude obstruction. However, in children and adults with a clinical picture of APN, diuretic MAG3 scintigraphy with zero time injection of furosemide (MAG3-F0) was observed to display focal parenchymal abnormalities; regional dysfunction (focal parenchymal decrease in early uptake; slow filling in and prolonged late retention of activity); or, less frequently, fixed defects. This observation was further studied both retrospectively and prospectively, and its sensitivity and specificity for APN were compared with those of dimercaptosuccinic acid (DMSA). METHODS: In the retrospective study, for 36 children with UTI and regional parenchymal findings on MAG3-F(0), data were reviewed, analyzed, and compared with the results of concurrent DMSA studies. In the prospective study, for 57 children with clinical and laboratory findings suggestive of APN, the 2 radiopharmaceuticals were used for imaging sequentially and the results of the 2 studies were compared. The criteria for abnormal findings compatible with the diagnosis of APN were, for MAG3-F(0), regional parenchymal dysfunction and fixed focal defects and, for DMSA, focal defects without parenchymal loss. RESULTS: In all groups of patients, most abnormal MAG3-F(0) studies (80%) showed regional parenchymal dysfunction, but in some (20%) a fixed defect was found. Compared with DMSA and when both regional dysfunction and focal defects were considered, MAG3-F(0) was as sensitive as DMSA. Some patients had only MAG3-F(0) abnormalities, suggesting a slightly lower specificity for MAG3-F(0) compared with DMSA (86%); this finding needs further study, because it also raises questions about the sensitivity of DMSA, considering that only a small percentage of patients with clinically suggestive findings had abnormal study findings. In most patients with fixed defects on both DMSA and MAG3-F(0), follow-up studies showed no resolution, suggesting that a fixed defect on MAG3-F(0) may indicate either more severe APN or preexistent scars and that regional dysfunction may be a sign more specific for APN and prognostic of potential recovery. In addition, a pattern more specific for a scar--a fixed defect with a dilated regional calyx--was seen on follow-up MAG3-F(0). CONCLUSION: A fast (25-min) planar dynamic MAG3-F(0) study was found to be as sensitive at depicting focal parenchymal abnormalities in APN as was the 3- to 4-h DMSA routine procedure. The sensitivity and specificity of both studies need further evaluation.

Acute Disease↗
PubMed1999

The GATA factor AreA is essential for chromatin remodelling in a eukaryotic bidirectional promoter.

The linked niiA and niaD genes of Aspergillus nidulans are transcribed divergently. The expression of these genes is subject to a dual control system. They are induced by nitrate and repressed by ammonium. AreA mediates derepression in the absence of ammonium and NirA supposedly mediates nitrate induction. Out of 10 GATA sites, a central cluster (sites 5-8) is responsible for approximately 80% of the transcriptional activity of the promoter on both genes. We show occupancy in vivo of site 5 by the AreA protein, even under conditions of repression. Sites 5-8 are situated in a pre-set nucleosome-free region. Under conditions of expression, a drastic nucleosomal rearrangement takes place and the positioning of at least five nucleosomes flanking the central region is lost. Remodelling is strictly dependent on the presence of an active areA gene product, and independent from the NirA-specific and essential transcription factor. Thus, nucleosome remodelling is independent from the transcriptional activation of the niiA-niaD promoter. The results presented cast doubts on the role of NirA as the unique transducer of the nitrate induction signal. We demonstrate, for the first time in vivo, that a GATA factor is involved directly in chromatin remodelling.

Aspergillus nidulans↗
PubMed1999

Survival and complications of cuffed catheters in children on chronic hemodialysis.

Central venous catheters are being increasingly used as hemodialysis vascular access. We evaluated catheter survival, outcome predictors, and complications in a total of 36 catheters used in 13 children and young adults undergoing chronic maintenance hemodialysis through catheter for a duration of 10.4+/-5.6 months. Reasons for catheter failure were: thrombosis 12 of 36 (33%), infection 6 of 36 (17%), and extrusion 2 of 36 (5.4%). Catheters were lost to infection and thrombosis at 1.1 and 2.2 episodes per 1,000 catheter days, respectively. Symptomatic infections, Gram-negative and polymicrobial sepsis increased the risk of catheter failure. Most of the thrombotic episodes occurred in patients with inherent thrombotic tendency. The survival of the 36 catheters was 62% at 1 year. The survival of 13 randomly chosen catheters, 1 from each patient, was 85% at 1 year. The time from insertion to first complication correlated significantly with the outcome (P<0.03). We conclude that central venous catheters are still associated with a high rate of failure and may be a regular access choice only in a selected patient population with no inherent thrombotic tendency and no other option available for long-term hemodialysis.

Adolescent↗
PubMed1999

Abnormal urinary acidification in infants with hydronephrosis.

Distal renal tubular abnormalities have been observed in patients with dilated urinary tract disorders. The present study was undertaken to look for patterns in urinary acidification in infants with varying degrees of hydronephrosis due to either reflux or obstruction and occurring as unilateral or bilateral disease. Three groups of infants (mean age 3.7+/-3.8 months) were studied prospectively. Groups IA and IB included patients with hydronephrosis who were acidotic and non-acidotic, respectively. Group II served as controls and consisted of patients with diarrhea and secondary metabolic acidosis with no known renal disease. Serum electrolytes, creatinine, and urine pH were measured in all patients. Urinary titratable acidity, ammonium (NH4), and net acid excretion (NAE) were measured by the titrimetric method. Infants with hydronephrosis demonstrated lower urinary buffering capacity, reflected in low NAE in the face of acidosis. Deficiencies were noted in both titratable acid and NH4 excretion compared with control infants. Acidosis was as common in unilateral as in bilateral disease, regardless of severity score. These data confirm a defect in distal urinary acidification in infants with hydronephrosis, whether unilateral or bilateral. Immaturity and endogenous acid load may play a significant role in the manifestation of metabolic acidosis with unilateral disease.

Female↗
PubMed1999

ACE inhibition scintigraphy in the management of hypertension in children.

Angiotensin converting enzyme (ACE) inhibition scintirenography was performed to help establish the diagnosis and plan treatment of renovascular hypertension (RVH) in 57 hypertensive pediatric patients, 33 infants and 24 children older than 1 year. In 16 of 33 hypertensive infants, ACE inhibition scintirenography established the diagnosis of RVH from renal ischemia (due to aortic or renal arterial thrombi). Two scintigraphic criteria were used for the diagnosis of RVH: criterion I, ischemic and damaged kidney (a non-functioning kidney on or off ACE inhibition) and criterion II, ischemic but not damaged kidney (ACE inhibition induced deterioration of function of the kidney). When criterion I was present and the contralateral kidney was normal, ACE inhibitors could be used for treatment of hypertension without deterioration of renal function; kidneys satisfying criterion I eventually involuted or manifested growth arrest and frequently caused persistent RVH, even after resolution of the thrombus, requiring nephrectomy. When criterion II was present bilaterally, or it was associated with criterion I contralaterally, the use of antihypertensive drugs other than ACE inhibitors was necessary in order to prevent renal insufficiency or failure from ACE inhibitors. However, kidneys with criterion II showed normal growth and, following retraction or dissolution of the aortic thrombus, hypertension resolved. In 2 of 24 hypertensive children older than 1 year, the test was diagnostic of branch renal artery stenosis; RVH was cured by selective angioplasty. ACE inhibition scintirenography is useful in the evaluation and planning of treatment in children with hypertension and may predict the outcome of therapy and ultimate renal function.

Adolescent↗
PubMed1999

The function of CreA, the carbon catabolite repressor of Aspergillus nidulans, is regulated at the transcriptional and post-transcriptional level.

The creA gene of A. nidulans encodes a wide-domain regulatory protein mediating carbon catabolite repression. Northern blot analysis of creA mRNA revealed a complex expression profile: the addition of monosaccharides to a carbon-starved culture of A. nidulans provoked a strong transient stimulation of creA transcript formation within a few minutes. In the case of repressing carbon sources, creA mRNA levels were subsequently downregulated, whereas the high creA mRNA levels were maintained in a creA mutant strain and in the presence of derepressing monosaccharides. A high creA transcript level is essential to achieve carbon catabolite repression and is dependent on glucose transport and, at least partially, on the creB gene product. Subsequent downregulation of creA mRNA levels, on the other hand, is typical of carbon catabolite repression and requires a functional CreA recognition site in the creA promoter (and thus involves autoregulation) and formation of glucose-6-phosphate. Despite the presence of continuing high transcript levels of creA in the presence of derepressing carbohydrates, EMSA demonstrated the presence of only low levels of a CreA-DNA complex in respective cell-free extracts. Upon transfer of carbon catabolite derepressed mycelia to catabolite-repressing conditions, a CreA-DNA complex is formed, and this process is dependent on de novo protein synthesis.

Aspergillus nidulans↗
PubMed1999

Lack of association between schizophrenia and a pancreatic phospholipase A-2 gene (PLA2G1B) polymorphism.

Patients with schizophrenia (DSM IV, n = 149) and controls (n = 180) participated in a case-control association study in which a trinucleotide repeat polymorphism of pancreatic phospholipase A2 group 1B (PLA2G1B) was examined. Both African-American and Caucasian populations were included in this USA sample. There were no significant case-control differences, therefore his study does not support an association between schizophrenia and a PLA2G1B polymorphism on chromosome 12.

Adult↗
PubMed1999

Kidney transplantation at the University of Miami.

Of the 1,679 renal allografts performed at the University of Miami between January 1, 1979 and October 31, 1999, 1,154 were from cadaver donors (CAD), 515 were from living-related donors (LRD), and 10 were from living-unrelated donors. The 3 ethnic groups: Black Caribbean-African-American, Hispanic, and others were almost equally represented among recipients. Recipient ages ranged between 1-83 years. In the CAD group, HLA matching was emphasized so that no patient received a kidney with less than one DR match, and for the entire series a mean of 2.59 of 6 HLA antigens were matched between donors and recipients. Overall actuarial 20-year patient and graft survival rates were 65.3% and 30.7%, respectively, with 69.2% patient and 38.5% graft survival rates for LRD, and 65.6% patient and 29.0% graft survival rates for CAD recipients. Several factors adversely affected long-term graft outcome. African-Americans had an overall 20-year graft survival rate of 13.6% compared with 34% for non African-Americans (p < 0.001) (not dependent on patient survival). Diabetic patients had an overall 20-year graft survival rate of 13.5% versus 34.2% for non-diabetics (primarily dependent on patient survival). In the category of non African-American, non-diabetic patients under age 36 (n = 412), the 20-year patient survival rates in the LRD and CAD groups were 85.0% and 79.3%, respectively, and the graft survival rates were 55.7% and 46.5%, respectively. This differed markedly from the results for the entire series.

Adolescent↗
PubMed1998

The regulator of nitrate assimilation in ascomycetes is a dimer which binds a nonrepeated, asymmetrical sequence.

The regulation of nitrate assimilation seems to follow the same pattern in all ascomycetes where this process has been studied. We show here by in vitro binding studies and a number of protection and interference techniques that the transcription factor mediating nitrate induction in Aspergillus nidulans, a protein containing a binuclear zinc cluster DNA binding domain, recognizes an asymmetrical sequence of the form CTCC GHGG. We further show that the protein binds to its consensus site as a dimer. We establish the role of the putative dimerization element by its ability to replace the analogous element of the cI protein of phage lambda. Mutagenesis of crucial leucines of the dimerization element affect both the binding ability of the dimer and the conformation of the resulting protein-DNA complex. This is the first case to be described where a dimer recognizes such an asymmetrical nonrepeated sequence, presumably by each monomeric subunit making different contacts with different DNA half-sites.

Amino Acid Sequence↗
PubMed1998

Fungal peritonitis in pediatric patients.

Fungal peritonitis (FP) is a rare complication of peritoneal dialysis (PD). Although treatment with fluconazole (FCZ) has improved catheter survival and preservation of the peritoneal membrane, FP still carries a high morbidity and mortality in pediatrics. High-risk factors for FP include previous usage of systemic antibiotics and recurrent bacterial peritonitis. A prospective experience in the treatment of FP was conducted at the University of Miami/Jackson Children's Hospital from 1992 to 1997. All patients received either oral or intravenous loading dose of FCZ (5-7 mg/kg) followed by intraperitoneal (i.p.) FCZ (75 mg/L). Amphotericin B (amp B) was added when clinical sepsis was present. A total of 6 patients had FP (all Candida sp.; mean age: 6 years). Two of these patients were neonates with Tenckhoff-catheter placement at less than 1 week of age. Five patients achieved sterilization of the peritoneal fluid. One patient required catheter removal (C. tropicalis). The 2 neonates were infection free for 29 and 41 days, respectively, but both died of superimposed bacterial sepsis. The remaining 4 patients survived and completed 6 weeks of FCZ treatment. Two have had preservation of the peritoneal membrane for more than 1 year. The other 2 were switched to hemodialysis. We conclude that FCZ is an effective treatment for fungal peritonitis in pediatric patients. Adjunct therapy with amp B is usually necessary if sepsis is present. Although eradication of the fungus is possible in a majority of cases, neonates and immunocompromised hosts remain at high risk for morbidity and mortality.

Adolescent↗
PubMed1997

An OR nurse internship program that focuses on retention.

Today's health care environment has pushed OR managers to reconsider the skill mix of staff members and to use more surgical technologists and unlicensed assistive personnel, Health care administrators want to decrease the RN: surgical technologist ratio in an effort to cut costs. This financial constraint and the unavailability of experienced OR nurses has created the problem of having enough trained nurses in the OR. One tactic that may prevent the available positions for RNs from being filled by unlicensed assistive personnel is to train more nurses. Training programs organized around optimal patient outcomes may be more cost-effective than training focused on technical proficiency alone. This article describes retention strategies (ie, classroom study, OR training, work with preceptors) used in an OR nurse training program conducted at a southeastern teaching hospital.

Hospitals, Teaching↗
PubMed1996

Mycoparasitic interaction relieves binding of the Cre1 carbon catabolite repressor protein to promoter sequences of the ech42 (endochitinase-encoding) gene in Trichoderma harzianum.

The fungus Trichoderma harzianum is a potent mycoparasite of various plant pathogenic fungi. We have studied the molecular regulation of mycoparasitism in the host/mycoparasite system Botrytis cinerea/T. harzianum. Protein extracts, prepared from various stages of mycoparasitism, were used in electrophoretic mobility-shift assays (EM-SAs) with two promoter fragments of the ech-42 (42-kDa endochitinase-encoding) gene of T. harzianum. This gene was chosen as a model because its expression is triggered during mycoparasitic interaction [Carsolio, C., Gutierrez, A., Jimenez, B., van Montagu, M. & Herrera-Estrella, A. (1994) Proc. Natl. Acad. Sci. USA 91, 10903-10907]. All cell-free extracts formed high-molecular weight protein-DNA complexes, but those obtained from mycelia activated for mycoparasitic attack formed a complex with greater mobility. Competition experiments, using oligonucleotides containing functional and nonfunctional consensus sites for binding of the carbon catabolite repressor Cre1, provided evidence that the complex from nonmycoparasitic mycelia involves the binding of Cre1 to both fragments of the ech-42 promoter. The presence of two and three consensus sites for binding of Cre1 in the two ech-42 promoter fragments used is consistent with these findings. In contrast, the formation of the protein-DNA complex from mycoparasitic mycelia is unaffected by the addition of the competing oligonucleotides and hence does not involve Cre1. Addition of equal amounts of protein of cell-free extracts from nonmycoparasitic mycelia converted the mycoparasitic DNA-protein complex into the nonmycoparasitic complex. The addition of the purified Cre1::glutathione S-transferase protein to mycoparasitic cell-free extracts produced the same effect. These findings suggest that ech-42 expression in T. harzianum is regulated by (i) binding of Cre1 to two single sites in the ech-42 promoter, (ii) binding of a "mycoparasitic" protein-protein complex to the ech-42 promoter in vicinity of the Cre1 binding sites, and (iii) functional inactivation of Cre1 upon mycoparasitic interaction to enable the formation of the mycoparasitic protein-DNA complex.

Base Sequence↗