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Biomedical subjects

M Manes

Publications and source records attributed to M Manes.

At least 19 recordsLinked to original sources
PubMed2002

Long nocturnal dialysis.

BACKGROUND/AIMS: The continuous growth of the dialysis pool in our unit induced us to organize a third long nocturnal dialysis (LND) session, considering the excellent survival and rehabilitation results reported with this method. This paper analyzes the results and assesses the role of LND among the different dialytic treatment options. METHODS: Out of 18 patients on LND, 13 (12 males and 1 female, mean age 52 +/- 13 years, time on dialysis 21.8 +/- 23.8 months) with >6 months' experience were studied, and 9 underwent a further metabolic evaluation. LND was performed using 1- to 1.4-m(2) Hemophan membranes, bicarbonate buffer, 200-250 ml/min blood flow, and 300-500 ml/min dialysate flow, 8 h three times a week. Kt/V and protein catabolic rate (3-point classic urea kinetics), postdialytic weight, serum albumin, total protein, hemoglobin, Ca(2+), phosphate, intact parathyroid hormone, bioimpedance body water, blood pressure, and drug use (antihypertensives, phosphate binders, erythropoietin, vitamin D, hypnotics) were evaluated in each patient during hemodialysis and LND. In the metabolic study (done twice), sodium (compared with the Kimura model), potassium, phosphate, and urea were analyzed in blood and inlet and outlet dialysate after 0, 2, 4, 6, and 8 h. RESULTS: The mortality was low (1 death every 247 patient-months). After 19 +/- 8.1 months of LND, the postdialytic weight rose from 68.5 +/- 9.6 to 70.8 +/- 10.7 kg (p < or = 0.01), and the hemoglobin concentration rose from 10.8 +/- 2.2 to 11.8 +/- 1.8 g/dl (p < or = 0.05); phosphate dropped from 5.6 +/- 2.0 to 4.4 +/- 1.3 mg/ dl (p < or = 0.01) and the systolic blood pressure from 152 +/- 15 to 143 +/- 19 mm Hg (p < or = 0.05). In the metabolic study, the sodium profile was significantly lower during the last 4 h than in the Kimura model. The potassium concentration, stable between 4 and 6 h, rose against the gradient during the last 2-hour period. The behavior of sodium and potassium during the last part of the dialysis session can be taken to indicate exhaustion of the sodium/potassium pump. Phosphate showed a gradual reduction with no intradialytic and only a moderate postdialytic rebound. The postdialytic urea rebound was 23.4%. CONCLUSIONS: LND is a useful additional tool for nephrologists in treating chronic renal failure, it is easy to organize, and it shows overall good results. Together with other dialysis methods, this schedule permits individualized treatment for each uremic patient.

Adult↗
PubMed2001

A partition-limited model for the plant uptake of organic contaminants from soil and water.

In dealing with the passive transport of organic contaminants from soils to plants (including crops), a partition-limited model is proposed in which (i) the maximum (equilibrium) concentration of a contaminant in any location in the plant is determined by partition equilibrium with its concentration in the soil interstitial water, which in turn is determined essentially by the concentration in the soil organic matter (SOM) and (ii) the extent of approach to partition equilibrium, as measured by the ratio of the contaminant concentrations in plantwater and soil interstitial water, alphapt (< or = 1), depends on the transport rate of the contaminant in soil water into the plant and the volume of soil water solution that is required for the plant contaminant level to reach equilibrium with the external soil-water phase. Through reasonable estimates of plant organic-water compositions and of contaminant partition coefficients with various plant components, the model accounts for calculated values of alphapt in several published crop-contamination studies, including near-equilibrium values (i.e., alphapt approximately equals 1) for relatively water-soluble contaminants and lower values for much less soluble contaminants; the differences are attributed to the much higher partition coefficients of the less soluble compounds between plant lipids and plant water, which necessitates much larger volumes of the plant water transport for achieving the equilibrium capacities. The model analysis indicates that for plants with high water contents the plant-water phase acts as the major reservoir for highly water-soluble contaminants. By contrast, the lipid in a plant, even at small amounts, is usually the major reservoir for highly water-insoluble contaminants.

Lipids↗
PubMed2001

[Data from the Aosta Valley dialysis and transplant regional registry].

BACKGROUND: The need of collecting data concerning uremic local population requested by EDTA registry and, more recently, by the Italian dialysis and transplant registry (RIDT) has led different Italian regions to organize structures able to give such clinical and epidemiological informations. METHODS: In Aosta Valley (where live nearly 120.000 people) a data collection has been activated since 1981 on paper support and since 1995 (with data from December 1994) on computer registry. If compared to more experienced Italian structures, such as Piedmont and Lombardy regional registries, RDTVA has the advantage of receiving data from a unique Dialysis centre (composed by a hospital area and a limited care centre). RESULTS: During these years, according to what happened in the rest of Italy, in Aosta Valley the uremic population increased with a per million population (pmp) rate prevalence from 125 patients in 1981 to almost 1000 in 1998. Also the incidence showed a similar trend, with 110 patients/pmp in 1981-82 and 160 in 1997. The gross mortality rate concerning years 1995-98 was about 12%, the main death causes being cardiovascular events (60%), similarly to national data. CONCLUSIONS: Even with the limits deriving from small numbers, RDTVA, because of its favourable position, can play the role of epidemiological observatory for uremic diseases and contribute to future health policy.

Humans↗
PubMed2000

[Isolated acute renal failure secondary to sarcoidosis. Apropos of a case].

A 59-years-old male patient was admitted to our Service because of acute renal failure with maintained diuresis (creatinine at admittance 6.2 mg/dl), preceded by malaise and weight loss. Clinical examination was normal and no investigation lead to a sure differential diagnosis of acute renal failure. The only abnormal laboratory investigations were: marked hypercalcaemia (12.7 mg/dl), slightly depressed parathormone (10 pg/ml) and anemia (Hb 11.2 g/dl). Also instrumental investigations performed were inexpressive. The abrupt appearance of an unilateral 7th cranial nerve paralysis lead to start a steroid therapy followed, in some days, by the normalization of calcium level and by a partial improvement of renal function. A renal biopsy was finally performed which permitted the diagnosis of interstitial granulomatous nephritis according to a sarcoidosis disease. Steroid therapy was continued allowing to a progressive, although not complete, recovery of renal function. The case peculiarity consists of isolated renal lesions with a severe expression of renal disease. The absence of classical disease criteria (pulmonary involvement firstly), in our case total body Gallium-67 scintigraphy was normal, should not exclude the diagnosis of sarcoidosis. The authors underline the importance of renal biopsy in detecting interstitial renal lesions potentially leading to uremia.

Acute Kidney Injury↗
PubMed1999

[Dialysis in the elderly. Indications for and efficacy of hemodialysis].

In Italy, as in all industrialized countries, life expectancy is raised during the past 100 years; this trend leads to important implications in medicine and among nephrologists. The increased number of end stage renal disease patients living beyond 65 years, who start dialysis, has modified the typical picture in dialysis centers. The causes of this phenomenon are different, including an increasing number of chronic diseases, typical of the "third age", like type II diabetes mellitus or vascular disease, creation of treatment facilities and success of prevention. Besides goods results obtained in elderly dialysis patients, mainly due to a better psychological reaction to the treatment and to an easy achievement of a high dialytic dose (Kt/V), there are some negative aspects, like the hemodynamic intolerance or the difficulties to make an ideal vascular access. However, these problems don't discourage the nephrologist but rather they must lead to achieve a personalized or alternative treatment. Even if the quality of life and rehabilitation are quite acceptable in many elderly patients, so to justify the wide acceptance criteria, many ethical and medical problems concern the most serious cases. Also in this condition, a wide acceptance criteria, followed by a possible withdrawal (time limited trial of treatment), can represent a reasonable solution.

Aged↗
PubMed1997

Relation between blood pH and ionized calcium during acute metabolic alteration of the acid-base balance in vivo.

We induced metabolic alkalosis and acidosis in 10 healthy volunteers in order to analyse in vivo relation between pH and ionized calcium (cCa2+). In the alkalinization test, 2.7 mol/kg NaHCO3 was injected. In the acidification test, volunteers took 4 mmol/kg NH4Cl. Blood pH and cCa2+ (mmol/l) mean values (SD) baseline, after alkalinization and acidification tests, were: 7.363 (0.018), 7.456 (0.031), 7.244 (0.031), 1.27 (0.03), 1.14 (0.03) and 1.38 (0.04). Mean slope of regression log cCa2+/pH was -0.39 (SD 0.11). Such a slope differs after in vivo or in vitro changes, due to the in vivo rapid restoration of equilibrium between the plasmatic and interstitial compartments following changes in water and electrolyte concentrations. The type of acid-base alteration-respiratory or metabolic-influences pH changes, and consequently the regression slope. The in vivo slope for log cCa2+/pH in normal subjects (-0.21) is much the same as in acute respiratory alterations (-0.17), whereas it differs in acute metabolic alterations (present study). Bicarbonates play different roles: the same changes in pH cause greater changes in cCa2+ after acute metabolic rather than respiratory alterations. Ca2+ homeostasis is maintained in acute respiratory acid-base imbalance, despite wide shifts in pH, whereas in acute metabolic alterations even small pH changes have striking repercussions on cCa2+. The experimental angular coefficient for in vivo acute metabolic acid-base alterations differs from the theoretical one calculated by Thode's differential equation (-0.25).

Acid-Base Equilibrium↗
PubMed1997

[Diagnostic aspects in the determination of antineutrophil cytoplasmic antibodies].

We propose a four step flow-chart to define ANCA positivity and antigenic target. 1st step: indirect immunofluorescence test on ethanol-fixed human granulocytes (IIF-E), as screening test. Different staining patterns can be observed: a granular cytoplasmic fluorescence (C-ANCA), a smooth or fine granular perinuclear fluorescence (P-ANCA) and an intermediate pattern (X-ANCA). Antinuclear antibodies (ANA) may mimic P-ANCA. 2nd step: IIF test on formalin-fixed human granulocytes (IIF-F) differentiates true P-ANCA from ANA: most of P-ANCA show cytoplasmic pattern, whereas ANA are negative. 3rd step: IIF test on monkey liver sections (IIF-M) investigates simultaneous ANA and P-ANCA positiveness. P-ANCA positive sera show an exclusive reactivity with neutrophils infiltrating the portal tract, whereas ANA react with hepatocytes nuclei. 4th step: to characterize antigenic target, a solid phase assay, using purified proteins as substrates, is performed. We found 17 C-ANCA (6 PR3, 3 MPO, 1 Lys, 1 Cat G and 6 unknown antigens) out of 173 patients screened with IIF-E. 21 P-ANCA positive sera have been investigated by IIF-F test: 15 showed a cytoplasmic pattern; EIA test gave the following results: 6 MPO, 2 LF, 5 unknown antigens; 2 cases were positive for two antigens, MPO & LF. Using IIF-M on the 6 IIF-F negative sera, we observed: 2 false positives (ANCA-/ANA-), one ANCA+/ANA+ (antigen LF), 3 ANCA+/ANA- (unknown antigens). The flow chart suggested allows to analyse in detail ANCA, using easily available commercial kits.

Animals↗
PubMed1996

[Use of dual energy X-ray absorptiometry (DEXA) in the determination of total body water in patients undergoing chronic dialysis].

In order to assess Total Body Water (TBW), three methods are compared, in 18 patients on regular dialysis treatment: DEXA, Bioimpedance Analysis (BIA) and urea Kinetic Volume (V urea). The mean difference between gravimetric weight and Total Body Mass (TBM) DEXA is closed (1.04 kg, SD of differences 0.4 kg). The mean difference between delta pre-post HD gravimetric weight loss (2.6 kg) and delta pre-post TBM DEXA is--0.03 kg (SD 0.28). TBW measured with the three methods are (Liters): TBW DEXA = 31.2 (SD 5.2), TBW BIA = 29.7 (SD 5.2), TBW V urea = 29.1 (SD 4.8). TBW comparisons between the three methods are (Liters): TBW DEXA-TBW BIA = mean 1.5 (SD 3.8), r = 0.73. TBW DEXA-TBW V urea = mean 2.1 (SD 2.2), r = 0.88. TBW BIA-TBW V urea = mean 0.6 (SD 3.6), r = 0.80. Hydration index of lean body mass, calculated by assuming V urea as standard, is 0.69 (SD 0.05), range 0.62-0.77, in agreement with others studies. In conclusion DEXA, a useful method for body composition and nutritional status assessing, represents a new tool for measuring hydration status, combined with others TBW evaluation formulas (BIA or V urea).

Absorptiometry, Photon↗
PubMed1995

On-line dialysate urea monitor: comparison with urea kinetics.

The outputs of a new on-line dialysate urea monitor (UM) were compared to a urea kinetic model (UKM) and to dialysis direct quantification (DDQ) in 13 patients. As for urea extraction and predialysis urea level, a good degree of correspondence was found between UM and laboratory data. Kt/VUM (1.21) is intermediate between Kt/VUKM (1.28) and Kt/VUKM using the post-rebound urea value (1.14) or Kt/VDDQ (1.14). Passing and Bablok regression analysis indicated no systematic error between Kt/VUM and Kt/VDDQ. The percentage differences in nPCR by UM, UKM and DDQ were not significant, but the standard deviations were wide. The UM approach is very simple and practical, avoiding blood sampling, laboratory analysis and data handling. It is reliable enough for clinical practice. Compared with traditional urea kinetics, Kt/V computation by a mathematical elaboration of the dialysate urea profile drawn from several points theoretically invites fewer errors due to the analytical procedure.

Adult↗
PubMed1993

Tumor necrosis factor/cachectin in Crohn's disease. Relation of serum concentration to disease activity.

Inflammatory mediators seem to be involved in the pathogenesis of Crohn's disease. Tumor necrosis factor is a primary mediator of inflammatory responses which causes metabolic effects related to tissue wasting. The aims of this study were to establish the presence of tumor necrosis factor in Crohn's disease patients, to determine of its serum levels reflect disease activity and to examine the relationship if this cytokine with other assessments of the activity of the disease. Serum concentration of tumor necrosis factor, measured with a biological assay, was significantly raised in 56 Crohn's disease patients (201 determinations) as compared with 44 controls (P < 0.0001). Patients with inactive disease had significantly lower tumor necrosis factor levels (3.58 +/- 0.55 ng/mL) as compared to patients with active disease (8.17 +/- 1.01 ng/mL). There was a significant correlation between serum tumor necrosis factor concentration and disease activity (r = 0.237, P < 0.002). Higher tumor necrosis factor levels were detected in patients with colonic involvement (ileocolitis and colitis) as compared with ileal localizations, and the difference was significant (t = 2.16, P < 0.05). Besides, it correlated negatively with albumin, haemoglobin and cholesterol.

Adolescent↗
PubMed1986

Major histocompatibility complex-encoded class I molecules are absent in immunologically competent Xenopus before metamorphosis.

The expression of class I and class II major histocompatibility complex (MHC)-encoded antigens has been examined at various stages of the development of the clawed frog, Xenopus. By immunoprecipitation with alloantisera or xenoantisera from radio-labeled spleen and thymus lysates, and by mixed lymphocyte reaction analysis, it was determined that the same class II molecules are expressed throughout ontogeny. In contrast, by fluorescence on frozen sections of tadpoles and by immunoprecipitation, the class I molecule is not detected in tadpoles, but appears on all tissues at the climax of metamorphosis. Animals maintained as tadpoles for long periods of time by chemical treatment do express class I antigens; thus, their expression can be independent of other biochemical and morphological changes that occur at metamorphosis. Immunofluorescence detects an otherwise uncharacterized MHC-linked alloantigen on tadpole thymic epithelium from the earliest stages of thymus differentiation.

Animals↗
PubMed1980

Gender differences in visual discrimination by rats in response to malnutrition of varying durations.

Visual discrimination of hooded rats was tested at 3 months of age by a Lashley procedure. Three groups of rats were used: those with histories of protein deprivation for up to 20 generations, those with protein deprivation for a single generation, and well-nourished controls. Growth retardation was present to a similar degree in both genders of the 2 malnourished groups. Deficits in visual discrimination were observed in female animals with intergenerational malnutrition, but not in females with single-generation malnutrition. Males with intergenerational and single-generation malnutrition showed equal deficits in visual discrimination. These findings demonstrate that the performance of female rats is impaired only after prolonged exposure to malnutrition, whereas males are vulnerable after shorter periods.

Animals↗
PubMed1980

Varying deficits in visual discrimination performance associated with different forms of malnutrition in rats.

Visual discrimination at 3 months of age was examined by the Lashley jumping stand test to rats malnourished by one of the following techniques: intergenerational malnutrition over 14 to 18 generations; protein deficiency from birth on; rearing in large litters, and rotation among lactating and non-lactating females. All four treatments caused stunting during the litter period, but only the first two were associated with reduced weights at the time of testing. Deficits in visual discrimination were most severe in males and females with intergenerational malnutrition. Both large-litter rearing and protein deficiency for one generation impaired visual discrimination in males only, whereas rotation between lactating and non-lactating females did not reduce visual discrimination in either gender. It is possible that extranutritional factors associated with each type of malnutrition may serve either to enhance or diminish the impact of malnutrition on the nervous system.

Animals↗