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Biomedical subjects

C Combe

Publications and source records attributed to C Combe.

At least 55 records · Page 3Linked to original sources
PubMed1999

Volume flow measurement in hemodialysis shunts using time-domain correlation.

Volume flow was measured in 58 hemodialysis shunts (32 grafts and 26 radial fistulas) using the color velocity imaging-quantification method. This method is based on time-domain correlation for velocity calculation and integration of time-varying velocity profiles generated by M-mode sampling. Measurements were made in the brachial artery to estimate radial fistula flow or directly in the grafts. Intraoperator reproducibility was 14.9% for fistulas and 11.6% for grafts. Flow rate was significantly lower in abnormal shunts associated with a functional disorder or a morphologic complication (808 ml/min +/- 484) than in shunts associated with no abnormalities (1401 ml/min +/- 562). Receiver operating characteristic curves showed that a flow rate of 900 ml/min for fistulas and 1300 ml/min for grafts provided 81% and 79% sensitivity and 79% and 67% specificity, respectively. A functional disorder or a morphologic complication was associated with all fistulas and grafts in which flow rates were lower than 500 ml/min and 800 ml/min, respectively.

Adolescent↗
PubMed1998

[Secondary cubital paralysis from prolonged thoracic drainage].

In intensive therapy patients, thoracic drains are usually inserted in the lateral part of thorax with the extension tube crossing the posterior aspect of the upper limb. We report the cases of two sedated patients who experienced ulnar palsy from a thoracic drain located behind their elbow.

Accidents, Traffic↗
PubMed1998

[Effectiveness of valproic acid for postanoxic action myoclonus (Lance-Adams syndrome)].

We describe the case of a patient who experienced postanoxic action myoclonus after a transient cardiopulmonary arrest. Whereas benzodiazepines (clonazepam, midazolam, diazepam) were inefficient, valproic acid allowed a full control of the myoclonus. It is essential that the distinction between postanoxic action myoclonus and posthypoxic seizures is made early to avoid a delayed appropriate therapy and erroneous prognostic conclusions.

Adult↗
PubMed1998

Worksite and family education for dietary change: the Treatwell 5-a-Day program.

The National Cancer Institute's '5-a-Day for Better Health Campaign is examining the efficacy of interventions in increasing the consumption of fruits and vegetables to five or more servings a day. This paper presents the study design, intervention and baseline survey results of the Treatwell 5-a-Day project, a randomized, controlled worksite-based intervention study. Twenty-two community health centers were randomly assigned to either a Minimal Intervention, Worksite Intervention or Worksite Plus Family Intervention. The Worksite Intervention included participation of employee advisory boards, programs aimed at individual behavior change and programs aimed at changes in the worksite environment. The Worksite Plus Family Intervention incorporated family-focused interventions into the worksite program, including a learn-at-home program, family newsletter, family festival and materials mailings. A self-administered survey was conducted prior to randomization (mean response rate: 87%, n = 1359). Twenty-three percent reported consuming five or more servings of fruits and vegetables a day. Consumption of fruits and vegetables was directly associated with level of household support for healthy eating. The Treatwell 5-a-Day intervention model has the potential to enhance existing worksite-based intervention through incorporation of its family focus, especially given the association of household support with individual eating habits.

Adult↗
PubMed1997

[Spontaneous rupture of the esophagus (Boerhaave syndrome) in a patient with scleroderma treated by continuous ambulatory peritoneal dialysis].

Esophageal involvement is a common situation found in 50 to 80% of patients with scleroderma, but Boerhaave's syndrome is rare in this context. The authors report the first case of spontaneous esophageal rupture occurring in a chronic renal failure patient treated by continuous ambulatory peritoneal dialysis. In this observation, sclerodermal esophageal dyskinesia, chronic renal failure which is a classical cause of vomiting and the peritoneal dialysis which play an increasing role in the intraabdominal pressure are potential contributing factors to Boerhave's syndrome. In such patients presenting risk factors, even if they are asymptomatic, it seems reasonable to propose esophageal explorations with manometry or/and endoscopy looking for dyskinesia or other complications of gastro-esophageal reflux.

Esophageal Diseases↗
PubMed1997

Henoch-Schönlein purpura with immunoglobulin A nephropathy and abnormalities of immunoglobulin A in a Wiskott-Aldrich syndrome carrier.

Abnormalities of immunoglobulin A1 (IgA1) glycosylation have been described in patients with IgA nephropathy (IgAN), whether primitive or secondary to Henoch-Schönlein purpura. The Wiskott-Aldrich syndrome, an X-linked recessive disorder, is associated with abnormalities of IgA. Renal involvement with mesangial IgA deposition identical to that found in IgAN has been reported during this affection. We report the case of a female carrier of the Wiskott-Aldrich syndrome presenting with Henoch-Schönlein purpura and abnormalities of IgA glycosylation, as previously reported in patients with IgAN. The galactosylation abnormalities of IgA could be linked to the patient's status as carrier of the Wiskott-Aldrich syndrome and could contribute to the pathogenesis of IgAN.

Adult↗
PubMed1997

[Anuric renal insufficiency caused by bilateral ureteral lithiasis].

A 73-year-old man was admitted to the ICU for anuria. He reported no history of urinary disease. The abdominal roentgenography and two echographies showed an empty urinary bladder, a right ureteral calculus without dilatation of the urinary tract. Computed tomography demonstrated the presence of a left ureteral stone. Bilateral retrograde ureteroscopy and drainage allowed a rapid recovery. When the abdominal roentgenography and echography cannot explain the occurrence of anuria, the computed tomography, or better the helical CT, can demonstrate the presence of otherwise unrecognized calculi.

Acute Kidney Injury↗
PubMed1997

Antioxidant effects of a supplemented very low protein diet in chronic renal failure.

Increased peroxidation of lipids in red blood cells (RBC) in patients with advanced chronic renal failure (CRF) reflects increased generation of reactive oxygen species (ROS), which may contribute to the metabolic damage induced by CRF and to its progression. We have evaluated parameters indicative of lipoperoxidation (LPO) of RBC at baseline in patients with CRF compared to controls, and the effects of a very low protein diet supplemented with amino and keto acids and vitamins A, C, E (VLPD) over a 6-month period. The presence of peroxidation damage in CRF patients before the administration VLPD was demonstrated by elevated levels of free malondialdehyde (MDA) (p < .0003) and decreased levels of polyunsaturated fatty acids (PUFA), particularly C20:4 (p < .001), C22:4 (p < .0001) and C22:5 (p < .0001) when compared to controls. Similarly, RBC vitamin E content was significantly decreased (p < .0001) while enzymatic activities were unalterated. VLPD reduced erythrocyte LPO as suggested by (a) decreased levels of free and total RBC MDA (p < .003 and p < .03, respectively), (b) increased levels of PUFA, particularly C22:4 and C22:5 (p < .003 and p < .03, respectively), and (c) increased levels of vitamins A and E (p < .001 and p < .04, respectively) as compared to prediet results. Antioxidant enzyme activities were not modified. These results suggest that VLPD has a protective role against LPO of erythrocytes in patients with CRF.

Adult↗
PubMed1997

Low protein diet in uremia: effects on glucose metabolism and energy production rate.

Low-protein diets (LPD) increase insulin-mediated glucose disposal in chronic renal failure (CRF), but the fate of the better utilized glucose and the effect on energy production rate are unknown. Using a two-step (1 and 5 mU x kg(-1) x min(-1)) euglycemic hyperinsulinemic clamp combined with indirect calorimetry, we studied the effects of a LPD (0.3 g x kg(-1) x day(-1), supplemented with essential amino acids and ketoanalogs) in six patients suffering from chronic renal failure. After three months of diet, no significant change was observed concerning glomerular filtration rate, body wt, or arterial pH. In the postabsorptive state, plasma glucose and insulin levels were significantly lower, and energy production rose from 15.72 +/- 0.48 to 17.16 +/- 0.67 Cal x kg(-1) x min(-1) (P < 0.05). Insulin-stimulated glucose oxidation (2.36 +/- 0.29 vs. 3.37 +/- 0.35 mg x kg(-1) x min(-1); P < 0.05 at first clamp step) and nonoxidative disposal (P < 0.05 at both clamp steps) increased after LPD. This confirms that LPD ameliorates insulin sensitivity in CRF, even for low plasma insulin concentrations. Since energy production rate is increased by LPD, the caloric intake should be increased when protein intake is restricted.

Adult↗
PubMed1997

Hypoxia induces intercellular adhesion molecule-1 on cultured human tubular cells.

The adverse effects of acute renal ischemia are partly mediated through an infiltration of inflammatory cells into the tubulointerstitium. The expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) by resident renal cells (endothelial cells and tubular cells) may facilitate this process. We investigated whether hypoxia stimulates the expression of ICAM-1 by cultured human proximal tubular cells (HPTC). Hypoxic culture conditions (PO2 < 4 kPa) stimulated the expression of ICAM-1 by HPTC in a time-dependent manner (P < 0.0001) as demonstrated by quantitative flow cytometry analysis. Quantitative PCR demonstrated an increase in ICAM-1 transcription. Re-oxygenation of tubular cells did not increase ICAM-1 expression further. TNF alpha concentration in culture supernatants increased with hypoxia, but blocking experiments demonstrated that TNF alpha was not implicated in hypoxia-induced expression of ICAM-1. Furthermore, the cytokines IL-6 and IL-1 beta were not involved, but the effect of hypoxia was blocked by PDTC, an antioxidant that may inhibit the activation of the transcription factor NF-kappa B. These data demonstrate that hypoxia is a stimulus that induces the synthesis and expression of the adhesion molecule ICAM-1, presumably via the activation of NF-kappa B.

Antioxidants↗
PubMed1997

A low-protein diet improves insulin sensitivity of endogenous glucose production in predialytic uremic patients.

A low-protein, low-phosphorus diet (LPD) has been shown to improve insulin sensitivity in uremic patients; however, this improvement has not been studied at low physiologic concentrations of plasma insulin, and the metabolic pathways concerned with this improvement have not been located. We used the glucose clamp technique at a low (0.25 mU.kg-1.min-1) level of hyperinsulinemia associated with the infusion of D[6,6-2H2] glucose to assess the insulin sensitivity of endogenous glucose production (EGP). Eight nondialyzed uremic patients were studied before and after 3 mo on an LPD providing 0.3 g/kg protein, 5-7 mg P/kg, and 146 kJ/kg (67% of energy as carbohydrates and 30% as lipids) per day, supplemented with ketoanalog amino acids. Postabsorptive plasma glucose and insulin declined after 3 mo of the diet (plasma glucose: 5.0 +/- 0.1 mmol/L before compared with 4.7 +/- 0.1 mmol/L after the LPD, P < 0.05; plasma insulin: 82.4 +/- 20.7 pmol/L before compared with 48.8 +/- 6.0 pmol/L after, P < 0.05). Postabsorptive glucose turnover rates did not change with the diet (2.06 +/- 0.14 mg.kg-1.min-1 before compared with 2.11 +/- 0.17 mg.kg-1.min-1 after LPD; NS). The insulin metabolic clearance rate was enhanced after the diet, so a lower level of hyperinsulinemia was obtained during the clamp (168.8 +/- 28.1 pmol/L before compared with 115.2 +/- 14.7 pmol/L after; P < 0.05). However, EGP was more easily inhibited after the diet (0.90 +/- 0.31 mg.kg-1.min-1 before compared with 0.30 +/- 0.17 mg.kg-1.min-1 after; P < 0.05), providing evidence of an improved insulin sensitivity of this parameter. This beneficial influence takes place at a physiologic level of hyperinsulinemia, and it probably plays an important role in the better glucose tolerance that has been reported in uremic patients on an LPD. An abnormal insulin sensitivity of EGP may participate in the disturbances of glucose metabolism in chronic renal failure.

Adult↗
PubMed1997

Cyclosporin-A- and angiotensin-II-induced vasoreactivity in isolated glomeruli and cultured mesangial cells, 4 and 24 h after renal mass reduction: role of vasodilatory prostaglandins.

Subtotal nephrectomy in the rat is followed by early hypertrophy and functional adaptation of the remnant glomeruli in which mesangial cells seem to play a leading part. Using a morphoquantitative approach, we assessed the vasoconstrictive response to 1 microM cyclosporin A (CsA) or 0.1 microM angiotensin II (AII) of isolated glomeruli and cultured mesangial cells obtained from normal rats and from rats after five-sixths nephrectomy. In normal rats, a significant reduction of glomerular size was observed after the administration of vasoactive agents (-14% after 30 min exposure to CsA or AII). After five-sixths nephrectomy the vasoconstrictive response, which was preserved at the 4th hour (-12% at the 30th minute), disappeared at the 24th hour (-1.5% at the 30th minute), but was maintained in animals pretreated with indomethacin (-10% at the 30th minute). Similar responses were observed with cultured mesangial cells at the first passage. Inhibition of prostaglandin synthesis abolishes the adaptative adjustments observed in partially nephrectomized rats during the first days after surgery. These findings suggest that renal vasodilatory prostaglandins may participate in the compensatory hemodynamic adjustments following subtotal nephrectomy.

Adaptation, Physiological↗
PubMed1996

The beneficial effects of oral nifedipine on cyclosporin-treated renal transplant recipients--a randomised prospective study.

The aim of this study was to test the hypothesis that nifedipine will improve graft survival in cyclosporin A (CyA)-treated renal transplant recipients. One hundred and forty-seven patients were randomised to one of three regimens. Group A received CyA, 7 mg/kg per day, and prednisolone; group B followed the same regimen as group A plus oral nifedipine and group C received CyA, 4 mg/kg per day, prednisolone and azathioprine. Calcium channel blockers were avoided in groups A and C. The crude 2-year (P = 0.0223) and 4-year (P = 0.0181) graft survival was significantly better in group B (86% and 81%, respectively) than in group A (75% and 63%, respectively). Delayed initial function was seen least frequently in group B (10.2%) compared to groups A (31%) and C (28%; P < 0.01). Group B also experienced fewer rejection episodes than groups A and C (P < 0.05). We conclude that the combination of oral nifedipine and CyA significantly improves initial graft function, rejection frequency and long term graft survival.

Administration, Oral↗
PubMed1996

Effects of lipopolysaccharide and glucocorticoids on expression of interleukin-1 beta converting enzyme in the pituitary and brain of mice.

The present study was carried out to determine whether those factors which regulate the expression of IL-1 beta in immune and non-immune tissues are also able to regulate the expression of ICE. In a first experiment, mice were injected with LPS (10 micrograms/mouse, i.p.) and killed before, 1, 3 or 6 h after the injection. Total RNAs were extracted from the spleen, pituitary and brain (hippocampus and hypothalamus) and submitted to RT-PCR to determine the levels of ICE mRNA as compared to beta 2 microglobulin mRNA. ICE mRNAs were more abundant in the spleen and hippocampus than in the pituitary and hypothalamus but they were not significantly altered by LPS treatment. In a second experiment mice were submitted to adrenalectomy or a 15 min restraint stress and injected with saline or LPS (10 micrograms/mouse. sc). They were killed 1-2 h later and total RNA was extracted from the same tissues as in experiment 1. Adrenalectomized mice had significantly higher ICE mRNA levels whereas stressed mice had significantly lower ICE mRNA levels than their respective controls. These results are discussed with respect to the possible regulatory influence of glucocorticoids on the expression of ICE.

Adrenalectomy↗
PubMed1996

Adrenalectomy enhances pro-inflammatory cytokines gene expression, in the spleen, pituitary and brain of mice in response to lipopolysaccharide.

To assess the possible influence of endogenous glucocorticoids on cytokine expression in the brain, adrenalectomized mice and sham operated mice were injected with saline or lipopolysaccharide (LPS, 10 micrograms/mouse, subcutaneously) and the levels of transcripts for IL-1 alpha, IL-1 beta, IL-1ra, IL-6 and tumor necrosis factor-alpha (TNF alpha) were determined 2 h after treatment in the spleen, pituitary, hypothalamus, hippocampus and striatum, using semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Levels of IL-1 beta were measured by ELISA in plasma and tissues of mice sacrificed after the administration of LPS or saline. LPS induced the expression of pro-inflammatory cytokines at the mRNA level in all tissues under investigation, except for TNF alpha in the hippocampus. This effect was potentiated by adrenalectomy in the spleen for IL-1 alpha and IL-1ra, the pituitary for cytokines other than IL-1ra, the hypothalamus for all cytokines, the hippocampus for cytokines other than TNF alpha, and the striatum for IL-1 alpha and IL-6. In saline-treated mice, adrenalectomy increased IL-1 alpha and IL-1 beta gene expression in the hypothalamus and IL-1 alpha gene expression in the hippocampus and striatum. LPS increased plasma and tissue levels of IL-1 beta, as determined by ELISA, and this effect was potentiated by adrenalectomy in plasma and tissues other than the spleen. These results can be interpreted to suggest that endogenous glucocorticoids regulate the neural components of the host response to infection and inflammation by inhibiting cytokine expression in peripheral organs and the brain.

Adrenal Glands↗
PubMed1996

[Rheumatoid purpura in adults. Apropos of 40 cases].

Fourty cases of Henoch-Schönlein purpura in adults (21 females, 19 males--age 39 years) are reviewed [departments of nephrology (28 cases) and internal medicine (12 cases)]. Dermatological manifestations occur in 39 cases and are similar to those seen in children. Gastrointestinal involvement (23 cases) usually takes the form of abdominal pains or diarrhea; gastrointestinal haemorrhages are rare. These symptoms are less severe than in children in this review as in the literature. Joint manifestations (22 cases) disappear without sequelae. The outcome of the disease depends on the nephropathy, present in 33 patients (82.5%) (all of those of the department of nephrology (100%) and 42% of those of the department of internal medicine). In one third of cases, renal manifestation appears after the onset of the disease (until 24 months). As in the children, haematuria and proteinuria are quasi constant. The renal histopathology is a focal and segmental proliferative glomerulonephritis in 58%, with IgA deposition in the mesangium (16/21 cases). Treatment regimen includes steroïds (10 cases), combination of steroïds with immunosuppressive agents (8 cases), steroïds-immunosuppressive drugs-plasma exchange (2 cases), dapsone (1 case). Of the 26 patients followed for 27 months, 11 are in clinical remission, 7 have persistent proteinuria or hematuria, and 8 have chronic renal failure after 3 months to 13 years. In this review, renal insufficiency, hypertension and young age predict a poor outcome. This severe outcome is probably explained by the fact that most of our patients referred to renal units. Unlike in the children, in which the affection is usually an acute illness, Henoch-Schönlein purpura in the adults seems to be a chronic disease, with prognosis depending on the nephropathy.

Adolescent↗
PubMed1996

Fibronectin production by human tubular cells: the effect of apical protein.

In progressive renal disease the degree of renal failure correlates with interstitial scarring and the rate of progression correlates with the degree of proteinuria. This has led to the hypothesis that proteinuria may cause interstitial scarring. Human tubular cells (HTC) grown on permeable membrane supports were characterized to be predominantly of proximal tubular origin. HTC produce the matrix protein fibronectin in a polarised fashion the ratio of basolateral to apical secretion being 2.9 +/- 0.2 at 48 hours. The addition of serum proteins (1.0 mg/ml) to the apical medium resulted in increased basolateral secretion of fibronectin, 2.62 +/- 0.23-fold after 24 hours and 2.40 +/- 0.16-fold after 48 hours. Serum fractionation revealed that the stimulant to fibronectin production had a molecular weight 40 to 100 kDa. Platelet derived growth factor secretion was also stimulated to apical exposure to serum but transforming growth factor beta secretion was not detected. Addition of neutralizing anti-PDGF antibodies did not decrease fibronectin secretion. The activity of serum was not reproduced by albumin or by transferrin. Exposure of HTC to serum resulted in increased release of lactate dehydrogenase, suggesting a degree of cytotoxicity. This evidence could provide a mechanism for the link between proteinuria and interstitial scarring.

Albumins↗