Canopy and environmental control of root dynamics in a long-term study of Concord grape.

Below-ground carbon allocation represents a substantial fraction of net photosynthesis in plants, yet timing of below-ground allocation and endogenous and exogenous factors controlling it are poorly understood. Minirhizotron techniques were used to examine root populations of Vitis labruscana Bailey cv. Concord under two levels of dormant-season canopy removal and irrigation. Root production, pigmentation, death and disappearance to a depth of 110 cm were determined over two wet and two dry years (1997-2000). There was continual root production and senescence, with peak root production rates occurring by midseason. Later in the season, when reproductive demands for carbon were highest and physical conditions limiting, few roots were produced, especially in dry years in nonirrigated vines. Root production under minimal canopy pruning was generally greater and occurred several weeks earlier than root production under heavy pruning, corresponding to earlier canopy development. Initial root production occurred in shallow soils, likely due to temperatures at shallow depths being warmer early in the season. Our study showed intricate relationships between internal carbon demands and environmental conditions regulating root allocation.

Sustaining continuous ambulatory peritoneal dialysis after herniotomy.

Controversy still exists as to whether peritoneal dialysis (PD) treatment can be safely continued after herniotomy. Many nephrologists withhold PD treatment for several weeks after herniotomy for fear of dialysate leakage and hernia recurrence. Here, we report on 9 patients (2 women, 7 men) in whom herniotomy was performed for umbilical (n = 3), inguinal (n = 5), or cicatricial hernia (n = 2), or for open processus vaginalis (n = 2). Surgery was performed according to the Lichtenstein method with insertion of a polypropylene mesh and ligation of the hernia sac. In all patients, PD treatment was paused for the day of surgery and for 1-3 days postoperatively, depending on residual renal function. Over the next several days, low-volume (1.0-1.5 L), high-frequency (6 per day) exchanges were started. The patient's original PD regimen was gradually reinstated over the next 2-4 weeks. All patients recovered rapidly, with no uremia or dialysis-related complications. Particularly, no leakage and no hernia recurrence could be observed 3 months thereafter. None of the patients had to be hemodialyzed intercurrently. In conclusion, continuing a modified regimen of CAPD treatment after herniotomy seems to be safe, with excellent patient comfort.

Phthalic acid is the main metabolite of the plasticizer di(2-ethylhexyl) phthalate in peritoneal dialysis patients.

Di(2-ethylhexyl) phthalate (DEHP) is the most commonly used plasticizer in polyvinyl chloride (PVC) plastics, and is therefore a major constituent of continuous ambulatory peritoneal dialysis (CAPD) bags. Because DEHP is not chemically bound, it leaches out of the plastic matrix. Recently, we found that leukocyte function in vitro is impaired by a mixture of metabolites of DEHP. In the present study, we investigated the metabolism of DEHP in patients on CAPD. The study group consisted of 10 stable patients, on CAPD for at least 6 months, using a plasticizer-containing PVC PD system [ANDY Plus (Fresenius Medical Care, Bad Homburg, Germany)]. Effluent dialysate and urine samples were collected over 24 hours, and a 10 mL blood sample was drawn. Concentrations of DEHP and its metabolites mono(2-ethylhexyl) phthalate (MEHP), phthalic acid (PA), and 2-ethylhexanol (2-EH) were determined in urine, dialysate, and serum using gas chromatography/mass spectrometry. Additionally, the degree of glucuronidation of the phthalic acid esters in urine were determined. In serum, dialysate, and urine, PA was the predominant metabolite of DEHP (0.205 +/- 0.067 mg/L, 0.284 +/- 0.180 mg/L, and 1.34 +/- 1.00 mg/L, respectively), but concentrations of MEHP were low (0.0100 +/- 0.0056 mg/L, 0.022 +/- 0.008 mg/L, 0.011 +/- 0.0064 mg/L, respectively). Urinary MEHP was glucuronidated to approximately 15%. PA was 35% eliminated as a glucuronide. Unlike healthy subjects, PD patients do not eliminate DEHP mainly in the form of MEHP or MEHP metabolites. They further break these compounds down to PA. The fact that concentrations of PA in urine exceed by far the respective serum concentrations indicates that PA is secreted by the kidney. Further research on the toxicological aspects of plasticizers in uremic patients should take these findings into account.

[Cervical actinomycosis in systemic lupus erythematosus, nephrocalcinosis and distal renal tubular acidosis (type I-RTA)]. / Zervikale Aktinomykose bei systemischem Lupus erythematodes, Nephrokalzinose und distaler renaler tubulärer Azidose (Typ-I-RTA).

HISTORY AND CLINICAL FINDINGS: A 25-year-old woman presented with a painful soft-tissue swelling in the right neck, which made it impossible to assess the right cervical lymph nodes, while other lymph nodes were unremarkable on palpation. For 9 years she had been known to have polyarthritis. All joints were freely mobile and were without deformity or inflammatory signs. Flexion of the left elbow was slightly painful but freely mobile. There was no skin rash. INVESTIGATIONS: Erythrocyte sedimentation rate was 44 mm/h, there was a leucocytosis of 16,000 granulocytes/ml. There was hypokalaemia (3.5 mEq/l) and a metabolic hyperchloremic acidosis with a pH of 7.27 and a urinary pH of 6.5. Antinuclear and anti-ds-DNA antibodies were raised (ANA: 3.9 multiple of cutoff point [MOC; normal: 0-1.0]; anti-ds-DNA antibodies: 4.0 [normal: 0-1.0])-Fine needle aspiration cytology from the swelling revealed erythrocytes, double-refractory horny lamellae, cellular debris and only a few inflammatory cells. Abdominal ultrasound showed nephrocalcinosis. Microbiological cultures were negative. DIAGNOSIS, TREATMENT AND COURSE: Assuming a bacterial cause of the swelling antibiotic treatment with Phenoxymethylpenicillin (4 MU/d) was initiated. The local findings rapidly improved and the inflammatory parameters regressed to normal. 16 weeks after the initial admission the abscess recurred and biopsy now revealed actinomycetes with typical granules, confirming cervical actinomycosis. The other symptoms indicated autoimmune disease and, together with previous findings, established the additional diagnosis of lupus erythematodes, which caused the type 1 distal tubular acidosis. CONCLUSIONS: This case illustrates the basic approach of establishing an all-encompassing diagnosis that brings together seemingly isolated findings. It is especially in systemic disease that such diagnostic strategy will frequently lead to its recognition.

Severe thrombocytopenia and response to corticosteroids in a case of nephropathia epidemica.

Nine days after working in the woods, a previously healthy 32-year-old man fell seriously ill. His symptoms included high fever, chills, diffuse myalgia, severe headache, and back pain. On the fifth day of onset of symptoms, blood tests showed creatinine levels of 5.4 mg/dL accompanied by marked proteinuria. After admission to the hospital, a diagnosis of nephropathia epidemica (NE) caused by Puumala virus was made using solid-phase enzyme-linked immunosorbent assay (ELISA). The patient gradually recovered renal function without requiring dialysis. However, he surprisingly experienced a sharp decline in platelet count to a minimum of 2,000/microL with concomitant occurrence of petechiae and conjunctival hemorrhage. Prednisolone was initiated, resulting in a swift rise in platelets. Six days later, when the medication was withdrawn, a sharp decrease in platelets recurred. The steroids were then readministered for the next 3 months, thus reestablishing a stable platelet count. The immediate rise of platelets after administration of prednisolone supports the pathophysiological view of hantavirus infection as an immunologically mediated disease. Corticosteroids in the treatment of hantavirus-associated thrombocytopenia might need further systematic evaluation.

The yeast RNA1 gene product necessary for RNA processing is located in the cytosol and apparently excluded from the nucleus.

The yeast RNA1 gene is required for RNA processing and nuclear transport of RNA. The rna1-1 mutation of this locus causes defects in pre-tRNA splicing, processing of the primary pre-rRNA transcript, production of mRNA and export of RNA from the nucleus to the cytosol. To understand how this gene product can pleiotropically affect these processes, we sought to determine the intracellular location of the RNA1 protein. As determined by indirect immunofluorescence localization and organelle fractionation, the RNA1 antigen is found exclusively or primarily in the cytoplasm. Only a tiny fraction of the endogenous protein could be localized to and functional in the nucleus. Furthermore, the RNA1 antigen does not localize differently under stress conditions. These findings suggest that the RNA1 protein is not directly involved in RNA processing but may modify nuclear proteins or otherwise transmit a signal from the cytosol to the nucleus or play a role in maintaining the integrity of the nucleus.

Legg-Calvé-Perthes disease.

Legg-Calvé-Perthes disease is a disease occurring in otherwise healthy children. An understanding of the physiologic process of the disease and the purpose of various forms of treatment is essential for nurses caring for these children and their families. Nurses are in a position to assist the child and family to cope with the alterations in lifestyle that result from treatment of Perthes disease.

Limb lengthening with the Ilizarov external fixator.

The Ilizarov External Fixator is used to lengthen or widen bones, to correct angular or rotational defects, or to immobilize fractures. This article discusses techniques of application and care of the device; physiology and mechanics of limb lengthening and bone regeneration; and nursing strategies to achieve patient compliance and prevent complications.

Characterization of an essential Saccharomyces cerevisiae gene related to RNA processing: cloning of RNA1 and generation of a new allele with a novel phenotype.

The RNA1 gene product is believed to be involved in RNA metabolism due to the phenotype of a single conditionally lethal, temperature-sensitive allele, rna1-1. We cloned the RNA1 gene and determined that it produces a 1,400-nucleotide polyadenylated transcript. On a multicopy plasmid, the mutant rna1-1 allele partially complements the rna1-1 temperature-sensitive growth defect. This suggests that the temperature-sensitive nature of the rna1-1 allele results from the synthesis of a product with lowered activity or stability at elevated temperatures or from a decrease in synthesis of the rna1-1 product at the restrictive temperature. A chromosomal disruption of RNA1 behaves as a recessive lethal mutation. Haploids bearing the disruption were isolated by sporulating a diploid heterozygous for the disrupted allele and the rna1-1 allele and possessing an episomal copy of the RNA1 gene. Analysis of the rescued haploids bearing the chromosomal disruption indicated that the recessive lethal phenotype of the RNA1 disruption is not merely due to a block in spore germination. Unexpectedly, diploids heterozygous for the disruption and the rna1-1 alleles become aneuploid for chromosome XIII at a frequency of 2 to 5%. It appears that the disrupted RNA1 allele on a multicopy plasmid also promotes aneuploidy for chromosome XIII. Promotion of aneuploidy seems to be a phenotype of this particular allele of RNA1.

A double base change in alternate base pairs induced by ultraviolet irradiation in a glycine transfer RNA gene.

The glyUsuAGA mutation affects Escherichia coli tRNA Gl y GGG, changing it to an AGA missense suppressor tRNA. Sequence studies have shown that the mutation involves a double base subsitution at the first and third positions of the tRNA anticodon, the result being a change in the anticodon from CCC to UCU. A system has been developed to facilitate the detection of this novel mutation, and we have shown that ultraviolet irradiation and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) are effective in causing the double base change. A single observation of the mutation occurring spontaneously has been made also. The frequency of MNNG-induced glyUsuAGA mutations is compatible with their being caused by two separate mutagenic events. The frequency of UV-induced glyAGA mutations, however, strongly suggests that the occurrence of one base substitution strongly enhances the chance of finding the second substitution at the alternate position. In addition to the double change in the anticodon, the glyUsuAGA tRNA differs from tRNA Gl y GGG in that it bears a modification of the A adjacent to the 3' position of the anticodon. Most likely, this modified base is N-[9-(beta-D-ribofuranosyl)-purin-6-ylcarbamoyl] threonine.