A patient with hyperkalemia and metabolic acidosis

Uptake of potassium by extrarenal tissues, primarily muscle and liver, represents a major defense mechanism in the maintenance of normokalemia following an acute elevation in the serum potassium concentration. Insulin, epinephrine, and aldosterone all play major roles in maintaining the normal distribution of potassium between the intracellular and extracellular environment. In addition to hormonal regulation, changes in blood pH and tonicity also exert a strong influence on extrarenal potassium metabolism. Last, the serum potassium concentration per se directly influences its own cellular uptake and this transport mechanism appears to be inhibited by uremia.     

Nephrotic syndrome and renal failure associated with a novel glycolipid storage disorder

A 57-year-old Caucasian male presented with severe nephrotic syndrome and diffuse organomegaly; he subsequently developed renal failure and died. Intracellular, crystalloid material was identified by light and electron microscopy in bone marrow, liver, spleen, mesenteric lymph nodes, and kidneys. Tissue extraction analysis identified the material as glucocerebroside and its immediate precursor, ceramide lactoside. Although Gaucher's disease cannot be completely excluded, glycolipid profiles do not conform to those of known storage disorders. Additionally, electron-microscopic studies indicate that the structural features of the glycolipid deposits are different from those of previously described storage diseases. These findings suggest a unique crystalloid deposition as the probable cause of a multisystem process, which was associated with renal insufficiency and death.     

Reconstruction of the burned thumb.

The thumb accounts for 40 to 50% of hand function. Reconstruction of soft-tissue contractures include release and coverage with skin grafts or various local, regional, distant, or free flaps. Thumb length, so important for prehension and opposition, can be restored by phalangealization, pollicization, or toe-to-thumb transfer. Secondary techniques such as metacarpal distraction-lengthening or osteoplastic reconstruction are rarely indicated.     

Effects of lysine on bicarbonate and fluid absorption in the rat proximal tubule

The effects of lysine on bicarbonate and fluid reabsorption in the rat proximal tubule were studied by luminal and capillary perfusion in situ. The proximal tubule and peritubular capillaries were perfused with bicarbonate Ringer solution containing [14C]inulin. The rate of bicarbonate reabsorption (JHCO3) was estimated to be 124 +/- 9.5 peq.min-1.mm-1 using a pH membrane glass electrode. The rate of net fluid reabsorption (Jv) was 2.6 +/- 0.21 nl.min-1.mm-1. When 10 mM L-lysine was added to the luminal perfusate, a 35% reduction in JHCO3 and no change in Jv were observed. Increase of L-lysine concentration in the luminal perfusate to 20 mM did not reduce JHCO3 further nor did it influence Jv.l When 10 mM L-lysine was added to the capillary perfusate, a 13% reduction in JHCO3 was observed (NS). Increase of lysine concentration in the capillary perfusate to 20 mM significantly reduced JHCO3 by 26% (P less than 0.01). There was no significant change in Jv under both conditions. The effect of L-lysine in the lumen was related to its reabsorption kinetics, D-Lysine, which was not reabsorbed significantly, did not affect bicarbonate reabsorption in the proximal tubule. These results indicate that the inhibitory effect of L-lysine is related to the entry of lysine into the cell from the lumen.     

Rapid Identification of Candida albicans and Other Human Pathogenic Yeasts by Using Short Oligonucleotides in a PCR

A PCR system that can quickly and accurately identify 14 species of human pathogenic yeasts was developed. The procedure distinguished between nine species of a closely related clade, Lodderomyces elongisporus, Candida parapsilosis, a new Candida sp., C. sojae, C. tropicalis, C. maltosa, C. viswanathii, C. albicans, and C. dubliniensis and between another five more divergent species, Pichia guilliermondii, C. glabrata, C. zeylanoides, C. haemulonii, and C. haemulonii type II. A rapid DNA extraction procedure that yields purified DNA in about 1 h is also described. The system uses uniform conditions with four primers for each reaction, two 40- to 50-mer universal primers that serve as a positive control and two 23- to 30-mer species-specific primers. Species-specific primers were derived from a 600-nucleotide variable region (D1/D2) at the 5′ end of the large-subunit (26S) ribosomal DNA gene and were generally designed to use mismatches at the 3′ end. Universal primers were developed from conserved nucleotide sequences in the small-subunit (18S) rRNA gene. In this system, a control 1,200- to 1,300-base DNA fragment was produced in all reactions and a smaller 114- to 336-base DNA fragment was produced if the chromosomal DNA from the target species was present. The PCR procedure is rapid and easy to interpret and may be used with mixed cultures.     

个体化下肢小腿假肢接受腔设计的生物力学评价技术研究

作为传递体重、固定假肢的部件 ,接受腔对于小腿假肢使用的舒适性和方便程度有决定性的作用。本研究建立了基于有限元应力分析的小腿假肢生物力学评价技术平台 ,实现了小腿残端 /接受腔 3D几何建模与信息交互、三维有限元自动建模及应力分析。 3D模型与信息交互的实现基于得到广泛支持的OpenGL技术 ,有限元模型的构建采用了专门针对小腿残端 /接受腔结构特点的自动建模方法 ,通过构建档案数据库系统作为整个系统的操作平台。该技术平台可与现有的CAD/CAM系统相结合 ,为接受腔的个体化设计提供生物力学定量化依据。其临床应用将改善传统的设计流程 ,提高设计效率。同时 ,它也是未来构建接受腔设计专家 /智能系统的基础。     

The effects of chronic papillary necrosis on acid excretion

Complete papillary necrosis in rats can be induced within 1 month following a single injection of 2-bromoethylamine hydrobromide (BEA) (50 mg, i.v.). Utilizing a combination of clearance and balance techniques the effects of complete absence of the papilla was examined as regards urinary acidification, whole kidney glomerular filtration rate (GFR), single nephron GFR, and morphology. Whole kidney GFR was not different from control, however, the percent filtering juxtamedullary nephrons was markedly diminished (87.2±2.1 vs. 31.5±3.6% filtering, control vs. BEA, respectively,P<0.001) and significantly reduced in the superficial nephrons (80.6±3.6 vs. 62.2±6.1% filtering, control vs. BEA, respectively,P<0.05). There was a significant decrease in juxtamedullary single nephron GFR and an increase in the superficial single nephron GFR as assessed by the quantitative Hanssen's technique in the animals with chronic papillary necrosis. Complete papillary necrosis was associated with normal arterial bicarbonate concentration, pH, and plasma electrolyte concentrations. At the same degree of acidemia (induced by NH₄Cl administration) minimal urinary pH, ammonium excretion, and titratable acid excretion were not different than seen in age matched controls. The response to Na₂SO₄ infusion and phosphate infusion was the same in both groups of animals. The urineblood (U-B)pCO₂, an index of urinary acidification, was identical in BEA and control animals. Scanning electron microscopy showed scarring of the juxtamedullary glomeruli one month after BEA. The papilla was sloughed and lying free in the renal pelvis in every experimental animal. These data demonstrate that complete papillary necrosis is not associated with acidosis nor a defect in urinary acidification.     

Fluorescence in situ hybridization with peptide nucleic acid probes for rapid identification of Candida albicans directly from blood culture bottles

A new fluorescence in situ hybridization (FISH) method that uses peptide nucleic acid (PNA) probes for identification of Candida albicans directly from positive-blood-culture bottles in which yeast was observed by Gram staining (herein referred to as yeast-positive blood culture bottles) is described. The test (the C. albicans PNA FISH method) is based on a fluorescein-labeled PNA probe that targets C. albicans 26S rRNA. The PNA probe is added to smears made directly from the contents of the blood culture bottle and hybridized for 90 min at 55 degrees C. Unhybridized PNA probe is removed by washing of the mixture (30 min), and the smears are examined by fluorescence microscopy. The specificity of the method was confirmed with 23 reference strains representing phylogenetically related yeast species and 148 clinical isolates covering the clinically most significant yeast species, including C. albicans (n = 72), C. dubliniensis (n = 58), C. glabrata (n = 5), C. krusei (n = 2), C. parapsilosis (n = 4), and C. tropicalis (n = 3). The performance of the C. albicans PNA FISH method as a diagnostic test was evaluated with 33 routine and 25 simulated yeast-positive blood culture bottles and showed 100% sensitivity and 100% specificity. It is concluded that this 2.5-h method for the definitive identification of C. albicans directly from yeast-positive blood culture bottles provides important information for optimal antifungal therapy and patient management.