Pulmonary gas exchange during dialysis in patients with obstructive lung disease.

Hypoxemia occurs during routine hemodialysis and may contribute to morbidity, but its cause is not well understood. We reasoned that patients with COPD would be more vulnerable to abnormalities in gas exchange with dialysis. Thus, to investigate the cause of dialysis-related hypoxemia, we measured gas exchange in a group of stable dialysis patients with normal pulmonary function (n = 6) and a group of dialysis patients with COPD (n = 6). Measurements were made predialysis, at 1 h, and postdialysis with both acetate and bicarbonate dialysates. Acetate dialysis decreased PaO2 in normal and COPD patients at 1 h and postdialysis. Acetate-induced hypoxemia was associated with reduced respiratory CO2 excretion and hypoventilation but PaCO2 did not change. This decrease in CO2 excretion resulted from CO2 fixation during acetate metabolism and modest CO2 loss across the dialyzer. Hypoxemia occurred only postdialysis with bicarbonate dialysate in normal and COPD patients. An increased P(A-a)O2 occurred postdialysis with both dialysates, and was most consistently observed in the COPD patients. In summary, at least two mechanisms contribute to dialysis hypoxemia. With acetate dialysate, alveolar hypoventilation from CO2 unloading occurs at 1 h and postdialysis due to acetate metabolism. However, abnormalities in ventilation/perfusion contribute to postdialysis hypoxemia observed with both dialysates. In addition, the decrement in PaO2 associated with dialysis is similar in normal and COPD patients, although preexisting COPD makes postdialysis changes more apparent.

Localization of angiotensin II receptor subtypes in the rabbit adrenal and kidney.

The localization of subtypes of the angiotensin II receptor has been determined by autoradiographic techniques using iodinated angiotensin II and two nonpeptide antagonists that exhibit selective affinities. DuP 753 specifically displaces type 1 sites (AII-1) and PD123177 inhibits only type 2 sites (AII-2). The rabbit adrenal cortex contains predominately AII-1 sites and the few AII-2 sites that are present are nonuniformly distributed. In the rabbit kidney, the fibrous outer sheath contains exclusively AII-2 sites whereas the glomeruli of the renal cortex and the renal medulla exhibit only AII-1 sites.

Ileal perforation due to arteriovenous malformation in a premature infant.

Gastrointestinal arteriovenous malformations (AVM) in children are most commonly associated with bleeding. Although not previously reported, we present a case of an AVM associated with intestinal perforation in a premature infant.

Cytologic diagnosis of malignant melanoma metastatic to the endometrium.

A case of cytologically diagnosed malignant melanoma metastatic to the endometrium is presented. The literature on extragenital malignant neoplasms metastatic to the uterus was reviewed to document the rarity of this entity. The cytologic features of metastatic malignant melanoma are described along with a differential diagnosis of other lesions having pigmented cells such as primary pigmented lesions of the endometrium, primary malignant vaginal melanomas, benign pigmented lesions of the cervix and vagina, and pigmented conditions other than melanoma.

Entrapment of an exchange wire by an inferior vena caval filter: a technique for removal.

The anesthesiology literature does not describe entrapment of a guidewire by an inferior vena caval filter. Because anesthesiologists are involved in central access in various perioperative and intraoperative settings, consideration of this complication is important. A case of guidewire entrapment by an inferior vena caval filter and a unique technique for removal of the entrapped wire is presented.

Acetate dialysate versus bicarbonate dialysate: a continuing controversy.

The use of bicarbonate dialysate as the buffer during routine dialysis is growing. This discussion reviews several of the comparative trials in which bicarbonate and acetate buffers have been tested. Effects of the two buffers on BP, cardiac function, and pulmonary performance are discussed. Costs of the two systems are also compared. Patients who seem most likely to benefit from bicarbonate dialysate include those with a reduced muscle mass in whom a high sodium dialysate has not prevented hypotension.

Bowel infarction as a cause of death in dialysis patients.

Bowel infarction as a frequent occurrence in patients with end-stage renal disease has not been previously recognized. This report describes 12 dialysis patients with nonocclusive bowel infarction. All patients with bowel infarction had large weight losses secondary to vomiting, diarrhea, or ultrafiltration when undergoing dialysis, preceding the development of this disease. Of the potential risk factors analyzed, frequent and severe hypotension (systolic blood pressure, less than 100 mm Hg) when receiving dialysis occurred more commonly in patients developing bowel infarction. The weight loss was not often recognized initially as an important compromising problem. A fatal outcome was experienced in nine of the 12 patients. We conclude that bowel infarction may be a significant cause of morbidity and mortality in dialysis patients.

A modified acrosome induction test.

Many types of acrosome induction tests require special equipment and reagents that are not available to most clinicians; thus, simpler tests seem desirable. A modified acrosome induction test has been developed that uses basic reagents and a light microscope, which are available in most office settings. A hypoosmotic swelling test and a double stain (Bismark brown and rose Bengal) were combined to evaluate the viable acrosome reaction (AR) among 74 infertile men and 42 control men. The study included 34 infertile males without varicoceles, 20 with nonrepaired varicoceles and 20 with repaired varicoceles. On each test day, a specimen from a fertile donor was run as a control. The spontaneous acrosome reaction was recorded in semen before and after capacitation. The final % viable acrosome reaction equaled the capacitated value minus the spontaneous value for whole semen. The mean % viable AR among the control specimens was 16% with no values less than 10%. This mean value for controls was significantly greater than the mean % viable AR in each patient group. There were no overlaps in the 95% confidence intervals. When the study group was stratified according to normal acrosome induction tests or >10% viable AR, 30 patients had a normal test and 44 had abnormal tests. Six patients with varicoceles and an abnormal acrosome induction test had a varicocelectomy, and 2 (33%) converted their acrosome induction test to normal after at least 6 months of follow-up. Nine patients had in vitro fertilization (IVF), 3 had a poor result, and all had an abnormal acrosome induction test. Six had a good result with IVF and all 6 had a normal acrosome induction test. Thus, the acrosome induction test described in this report may be performed in any office laboratory to detect subtle male factor problems. The results may be helpful for planning IVF, intracytoplasmic sperm injection, or varicocele surgery for infertile men.

Endoscopic retrieval of retained Jackson-Pratt drain.

Jackson-Pratt (JP) drains are commonly used after urologic surgery. One of the complications associated with the use of JP drains occurs when the drain breaks, leaving the distal fenestrated part at the time of attempted removal. We describe the endoscopic retrieval of a retained JP drain, which was safely performed with local anesthesia and minimal risk.

Evaluation of prostate volume by transrectal ultrasonography for use in a brachytherapy program.

OBJECTIVES: To evaluate two methods of measuring the prostate volume using transrectal ultrasonography. The measurements were performed in vivo at preplanning and again preoperatively in connection with brachytherapy. The accurate measurement of the prostate volume is important in a brachytherapy program for treatment planning. METHODS: A total of 43 patients with biopsy-proven prostate cancer underwent prospective determination of the prostate volume, by one physician, using transrectal ultrasonography. Volume calculations were made at the preplanning and preoperative settings, both by a hand-held rectal probe using the prolate ellipsoid formula and by a mounted probe in a stepping device using the planimetric method. RESULTS: The coefficient of variation between the preplanning and preoperative prostate volumes with the probe holder was less than 3% compared with the hand-held probe, which was greater than 10%. The difference between the median values at the preplanning and preoperative settings by serial planimetry was 2.5 cm(3) (range 0.2 to 9.4). The difference in the median volumes between the preplanning and preoperative ellipsoid calculations was 6.7 cm(3) (range 0.3 to 38.7). The difference between the median values with the ellipsoid volume was significant (P <0.001). The Pearson correlation coefficient for all values using the planimetric method was 0.92 versus 0.58 for the ellipsoid method. The correlation coefficient was significantly greater for the planimetric method (P <0.001). CONCLUSIONS: On the basis of these data, planimetric prostate volume determination, by a single ultrasonographer, is an accurate and reproducible method with applicability to a brachytherapy program.

High-flow priapism: a novel way of lateralizing the lesion in radiologically inapparent cases.

High-flow priapism is a rare entity, which is typically diagnosed with the help of either color flow Doppler ultrasound or arteriogram. In the case presented, both of these diagnostic modalities were unsuccessful in uncovering a vascular lesion. The patient underwent an empiric selective embolization of the left pudendal artery followed by a repeat angiogram of the right because of persistent tumescence. This procedure uncovered a previously unseen arteriolacunar fistula, which was treated successfully with a second selective embolization.

Antiproliferative gene BTG1 is highly expressed in apoptotic cells in macrophage-rich areas of advanced lesions in Watanabe heritable hyperlipidemic rabbit and human.

In the present study, the expression and potential role of the highly conserved antiproliferative gene BTG1 in the process of apoptosis as it occurs in atherosclerotic lesions was examined. In situ hybridization and immunodetection studies demonstrated that BTG1 localized to specific macrophage-rich regions of lesions in both Watanabe heritable hyperlipidemic rabbits and humans. In addition, the spatial distribution of BTG1 mRNA was shown to colocalize not only with macrophage-rich regions but also to cells that exhibited changes consistent with apoptosis, such as DNA fragmentation and nuclear condensation. In vitro studies demonstrated that forced overexpression of BTG1 induced a 3-fold increase in apoptosis in NIH/3T3 cells. Furthermore, significantly increased expression of BTG1 mRNA resulted from lipid loading of human monocyte-derived macrophages in vitro. The process of increasing lipid content in macrophages is frequently associated with decreased macrophage viability. Taken together, these data underscore a potentially important role for BTG1 in regulating the cellularity of advanced atherosclerotic lesions.

Distal neuropathy in experimental diabetes mellitus.

Although nerve conduction slowing is a well-accepted abnormality in rats with acute experimental diabetes, reports of neuropathological changes in diabetic rat nerves have been inconsistent. To examine this further, we studied electrophysiological and morphological features of posterior tibial nerves and their distal branches from four-week streptozotocin-induced diabetic rats and matched controls. Diabetic rat posterior tibial motor conduction was slowed (mean +/- 1 SD, 34.8 +/- 3.1 m/sec; controls, 41.2 +/- 2.5 m/sec), and evoked muscle response amplitudes were only half of control values. Using quantitative techniques, we documented a diminution in number of the largest myelinated fibers in otherwise normal mid posterior tibial nerves, with an increase in the smaller sizes, indicating either a degree of axonal atrophy or impaired fiber growth during development. The principal pathological finding was active breakdown of myelinated fibers in the most distal motor twigs of hindfoot muscles supplied by posterior tibial branches, with preservation of fibers in more proximal segments of these nerves. This anatomical lesion in diabetic nerves could account for both oberved conduction slowing and lowered muscle response amplitudes. A consistent feature in both diabetic and control mid lateral plantar nerves was a zone of demyelination that apparently occurs at this natural site of nerve entrapment in rats. Taken together, the pathological abnormalities of peripheral nerve in acute experimental diabetes are best explained as resulting from a distal axonopathy.

alphavbeta3, alphavbeta5, and osteopontin are coordinately upregulated at early time points in a rabbit model of neointima formation.

Both smooth muscle cell migration and replication are known to be responsible for neointima formation. Recent reports based on in vitro studies and animal models of neointima formation highlight the possible importance of alphavbeta3 and alphavbeta5 integrins in mediating neointima formation. Clinical data suggest that specific alphavbeta3 blockade may limit restenosis. The aim of this study was to identify the expression of alphavbeta3 and alphavbeta5 and their ligand osteopontin in the very early phases of neointima formation in a rabbit model. A non-occlusive cuff placed around the rabbit femoral artery resulted in a complete, concentric neointima that formed by 14 days. Antibodies specific for the integrin heterodimers and for osteopontin, along with a probe specific for osteopontin mRNA, were used to identify expression at early time points (6 h, 1 day, 3 days, 5 days) post-cuffing. Immunohistochemistry and in situ hybridization expression results were quantitated by image analysis and tested for statistical significance by a two-tailed t-test. The data demonstrated the rapid (within 6 h) and abundant upregulation of alphavbeta3 and alphavbeta5 integrins and their ligand during very early time points of neointima formation. The very early (6 h) upregulation of alphavbeta3 underscores a potentially important clinical intervention point in limiting restenosis following clinical angioplasty procedures.