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Biomedical subjects

P Ponce

Publications and source records attributed to P Ponce.

At least 19 recordsLinked to original sources

Gliomatosis cerebri: findings with computed tomography and magnetic resonance imaging.

Gliomatosis cerebri (GC), is a rare neoplastic disease (less than 150 cases reported in the literature) with a diffuse, widespread proliferation of neoplastic glial cells in the brain, generally affecting both hemispheres and involving the gray and white matter [1-3]. Less commonly, the cerebellum, the brain stem and the medulla can be affected. Histologic evaluation reveals neoplastic astrocytes with varying levels of differentiation. Perineuronal and perivascular spread of tumor infiltration is observed. Demyelination can be found in the affected areas. A well-preserved underlying neuroanatomic architecture is considered characteristic [2]. Clinical signs vary and are non-specific, including changes in the mental state and headaches, followed by focal motor deficits and convulsive episodes [4]. The prognosis is poor, ranging from weeks to some years after the manifestation of the symptoms. Steroids may be useful in the short term, but chemotherapy is of little value and radiotherapy of questionable benefit. The literature was reviewed and the radiological pattern of three new cases of GC is reported. In two cases the diagnosis was achieved ante-mortem.

Adult

Iron supplementation in haemodialysis--practical clinical guidelines.

BACKGROUND: The aim of this prospective study was to test a new protocol for iron supplementation in haemodialysis patients, as well as to assess the utility of different iron metabolism markers in common use and their 'target' values for the correction of iron deficiency. METHODS: Thirty-three of 56 chronic haemodialysis patients were selected for long-term (6 months) i.v. iron therapy at 20 mg three times per week post-dialysis based on the presence of at least one of the following iron metabolism markers: percentage of transferrin saturation (%TSAT) <20%; percentage of hypochromic erythrocytes (%HypoE) > 10% and serum ferritin (SF) <400 microg/l. Reasons for patient exclusion were active inflammatory or infectious diseases, haematological diseases, psychosis, probable iron overload (SF > or =400 microg/l) and/or acute need of blood transfusion mostly due to haemorrhage and change in renal replacement treatment. RESULTS: More than half (51.8%) of the patients of our dialysis centre proved to have some degree of iron deficiency in spite of their regular oral iron supplementation. At the start of the study the mean haemoglobin was 10.8 g/dl and increased after the 6 months of iron treatment to 12.8 g/dl (P<0.0001). The use of erythropoietin decreased from 118 units/kg/week to 84 units/kg/week. The criterion for iron supplementation with the best sensitivity/specificity relationship (100/87.9%) was ferritin <400 microg/l. Patients with ferritin < 100 [microg/l and those with ferritin between 100 microg/l and 400 microg/l had the same increase in haemoglobin but other parameters of iron metabolism were different between the two groups. CONCLUSIONS: Routine supplementation of iron in haemodialysis patients should be performed intravenously. Target ferritin values should be considered individually and the best mean haemoglobin values were achieved at 6 months with a mean ferritin of 456 microg/l (variation from to 919 microg/l). The percentage of transferrin saturation, percentage of hypochromic erythrocytes and ferritin <100 microg/l, were not considered useful parameters to monitor routine iron supplementation in haemodialysis patients. No significant adverse reactions to iron therapy were observed.

Anemia, Iron-Deficiency

Cerebritis due to Listeria monocytogenes: CT and MR findings.

Infections by Listeria monocytogenes are uncommon, with cerebritis being even rarer. We present three cases of cerebritis which occurred during an outbreak of listeriosis. The CT and MR findings at diagnosis and during follow-up are described. Predominant deep white matter lesions with nodular and ring enhancement were seen. The MR yielded a higher resolution of the lesions than CT.

AIDS-Related Opportunistic Infections

[Hospital prevalence of kidney failure. Consequences and reflections for the planning of nephrology services].

A prospective prevalence study of Renal Failure (RF) in inhospital patients (creatinine > = 1.7 mg/dl) was carried out during March 1994, in two hospitals covering well defined and mutually exclusive populations. Cases were selected by screening all urea and creatinine blood tests performed in both laboratories, and registered in an individual form for daily follow-up of their nephrologic outcome. We registered 242 RF cases among 3525 patients admitted (6.8%), with an A.R.F. prevalence of 5.2%, 46% of all patients had a serum creatinine > 3 mg/dl and 71% were older than 65 years. In 55% RF was acquired inside the hospital. The most frequent cause of A.R.F. was pre-renal failure with 37%, followed by 32% of ischemic acute tubular necrosis and 13% toxic ATN. Nephrology was consulted in only 29% of all hospital RF cases. Only 17% of the RF patients were submitted to dialysis procedures, overall mortality was 31%, and 30% had normal renal function at discharge. Our results provide a data base to rethink the organization, staffing and role of nephrology departments inside general hospitals.

Female

[A diaphragmatic pacemaker in the treatment of ventilatory failure].

Diaphragmatic Pacing was used to treat ventilatory failure in a young boy with bilateral diaphragmatic palsy secondary to cervical cord injury, on chronic mechanical ventilation for 6 months. The indications for diaphragmatic pacing in ventilatory failure were discussed, as well as the assessment of phrenic nerve integrity and the pacing schedules utilized to slowly improve the diaphragm endurance and achieve a full-time weaning from mechanical ventilation.

Brain Injuries

[Consequences of the correction of post-transplantation hypophosphatemia on mineral metabolism].

AIM: To study the effect of the correction of post-transplantation Hypophosphatemia on mineral metabolism. PATIENTS: 15 patients with renal transplants for 3 to 12 months, Serum Creatinine "177 micmol/1, were treated with oral phosphorus (P) for persistent hypophosphatemia. METHODS: 3 periods of blood and urine collection at intervals of 3 weeks. T1 under basal treatment with oral P, T2 after 3 weeks off medication with P, Ca, or P binders. T3 3 weeks after going back on oral P supplements. RESULTS: Serum P dropped from T1 to T2 (1.03 +/- 0.03 mmol/L to 0.83 +/- 0.03 mmol/L, p "0.0001), rising again in T3 to 1.06 +/- 0.03 mmol/L. From T1 to T2, PTHi decreased from 95.4 +/- 8.7 to 66.8 8.9pg/ml), osteocalcin rose from 3.8 +/- 1.2 to 16.6 +/- 2.3ng/ml (p<0.001) and 25-Vit D rose from 16.7 +/- 1.9 to 21.4 +/- 2.1 ng/l (p<0.001), with the reversal of these changes from T2 to T3 when serum P increased once again. There was a significant correlation between serum P and PTHi and serum P and 25-Vit D. There were no significant variations of the serum Ca, Alk. Phosph., ICTP and CaFE values in the three periods. CONCLUSIONS: 1-Serum P never dropped below 0.55 mmol/L, which had no clinical consequences, 2- When the P dropped, PTHi also dropped and osteocalcin and 25-Vit D rose, without any major variation in bone catabolism, 3- Correction of hypophosphatemia may delay recovery from secondary hyperparathyroidism.

Adolescent

Renal tubular sodium and water metabolism in brain tumour patients submitted to craniotomy.

PURPOSE: To evaluate the effect of Brain Tomour (BT) and Neurosurgery (NS) on the renal handling of H2O and Na, and the clinical importance of SIADH in this setting. METHODS: Fourteen patients with BT pre-op for NS and 6 controls (C) pre-op for general surgery, were assessed in a controlled prospective trial. All patients were normovolaemic, with normal renal function. They received 400 mg of lithium carbonate (Li) 8 hours before each of two test periods (I and II) and a standard water load only before period II. Clearances studies were performed pre-op (period I) and 24 hours post-op (period II). RESULTS: Serum Na was normal at all times. Despite normovolaemia, a 1% decrement in serum osmolality and the water load, ADH dramaticaly increased from time I to II mainly in the BT group (36.2 +/- 9.4 vs 7.1 +/- 0.6 pmol/L, p = 0.02). FENa, FELi and FEUricA were significantly more elevated in the BT group pre and post-op (at time II respectively 4.6 +/- 1.6 vs 1.1 +/- 0.3%; 29.3 +/- 4.9 vs 22.6 +/- 5.5; 26.0 +/- 8.1 vs 11.3 +/- 2.2, p = 0.03). Proximal and distal H2O re-absorption and distal fractional Na re-absorption were identical in both groups pre and post-operatively. CONCLUSIONS: 1-BT and NS always induce a SIADH. 2-There was a primary Na loss at the proximal tubule level not explained by ADH increment, that did not significantly changed H2O handling. 3-To prevent hyponatraemia, hypotonic I.V. fluids should be avoided, but more importantly saline must be provided to this potentially salt-wasting condition.

Adult

Renal toxicity mediated by continuous infusion of recombinant interleukin-2.

Interleukin-2 (IL-2), a potent lymphokine with antitumoral activity, was used in continuous intravenous infusion for 5 days (18,000,000 IU/m2/day) in 9 treatment cycles in 5 patients with metastatic colorectal carcinoma. During the infusion, patients received aggressive fluid replacement titrated by invasive hemodynamic monitoring, aiming at a stable central volemia. Body weight went up an average of 4.5 kg in 5 days, mean arterial blood pressure dropped slightly from day 1 to day 5 (105.4 +/- 11.6 to 86.1 +/- 12.5 mm Hg, p < 0.05), systemic vascular resistance decreased from 1304.7 +/- 242.1 to 871.7 +/- 237.2 dyn/s/cm-5 (p < 0.05), with stable pulmonary capillary wedge pressure, cardiac output and central venous pressure. The urinary output significantly dropped from 1.9 +/- 1.2 to 0.2 +/- 0.1 ml/min (p < 0.05) with very significant rises in serum creatinine from 76.0 +/- 28.3 to 242.2 +/- 144.9 mumol/l (0.86 +/- 0.32 to 2.47 +/- 1.64 mg/dl) and N-acetyl-beta-D-glucosaminidase urinary activity from 4.97 +/- 5.0 to 23.0 +/- 12.1 U/l, and significant decrement of creatinine clearance (1.86 +/- 0.65 to 0.29 +/- 0.27 ml/s or 111.5 +/- 38.9 to 17.1 +/- 16.6 ml/min) and urinary sodium (113.8 +/- 78.3 to 9.0 +/- 6.7 mmol/l). Urine sediment evolved from normal at day 1 to 9.0 +/- 3.7 epithelial cells/mm3 and 6.9 +/- 3.6 brown casts/mm3 (p = 0.001). We concluded that cancer treatment with IL-2 in continuous infusion, even with stable hemodynamics, induces an acute renal failure in most patients treated.

Acute Kidney Injury

[Prevention of thrombogenesis in the extracorporeal circuit of hemodialysis with a low molecular heparin: standardization of the dosage with a better hemorrhagic risk/effectiveness ratio].

PURPOSE: To test the efficacy and safety of a low molecular. Weight heparin (LMWH)--Fraxiparine, for hemodialysis (HD) anticoagulation, compared with conventional heparin (H) or serum lavage without other anticoagulation (L). DESIGN: Prospective controlled study. PATIENTS AND METHODS: Twenty-nine consecutive patients referred for dialysis in a tertiary care hospital were divided in 3 groups A, B and C, each group A and B patient submitted to 2 dialysis, AI and AII, BI and BII. Group A--n = 10, no bleeding risk, single needle technique, blood flow (Qb) less than 200 ml/min. HD-AI used LMWH 10,000 U pre-HD, HD-AII used H for an ACT 1.5 to 2 times baseline; group B--n = 10, high bleeding risk, double needle dialysis, Qb--200 to 300 ml/min. HD-BI used LMWH 5000 U pre-HD, and HD-BII used only L; Group C--n = 9, no bleeding risk, Qb less than 200 ml/min, all received LMWH 5000 U pre-HD. A semiquantitative screening was done in each dialysis for the presence of dialyser or venous chamber clots, APTT and Anti Xa activity were measured every 30 min., as well as pre and post-dialysis Hb, Htc, and platelets. RESULTS: APTT didn't rise significantly during HD with LMWH in contrast with the AII group with H (32.2 +/- 7.1 vs 63 +/- 25.8, p less than 0.05). The APTT levels in all dialysis with LMWH were identical to BII dialysis With L. Anti xa activity had an early peak at 30 to 60 min. With LMWH (0.62 +/- 0.45 em AI) and a late one at 180 min with H (0.39 +/- 0.2). There was no significant differences between pre and post-dialysis corrected platelet counts, but the lavage group showed the greater decrements (-20% +/- 24). In all the 49 dialysis we had 5 cases of complete clotting of the blood circuit, all of them in the lavage group C. No patients with high risk of hemorrhage had any bleeding increment. CONCLUSION: LMWH prevents clotting as effectively as H, in low doses of 5000 anti Xa units it doesn't interfere with PTT and is far more effective than HD with serum lavage in patients with bleeding risk and/or low blood flow in the dialysis circuit.

Adult

[Mesenteric ischemia in hemodialysis].

Eighteen hemodialysis patients with the diagnosis of mesenteric ischemia (MI), admitted to the Renal Service in the last 5 years, were retrospectively reviewed. All patients, 10 males and 8 females, average age 66.3 +/- 8.6 years, were complaining of acute abdominal pain without other specific clinical or laboratorial findings, had their diagnosis confirmed during laparatomy, with ischemic involvement of the ileocecal/ascendant colon area in 14 cases and the small bowel in 4. Noteworthy was the high incidence of previous dialysis-induced hypotensive episodes (10/18), the presence of leukocytosis (13/18), the high average hemoglobin level of 9.4 gr/dl, and the constant finding of non-occlusive MI. Average time in-hospital was 15.4 days (2 to 30) and the mortality--88% (16 patients). The growing incidence of MI mostly of the non-occlusive type, and its grim prognosis, calls for an early diagnosis of functional ischemic colitis, and the adoption of preventive action to avoid bowel infarction.

Aged

Renal involvement in leprosy.

Renal involvement in Hansen's disease was evaluated in 94 Portuguese patients, average age and duration of disease of 47.6 and 6.8 years respectively. Sixty-seven were studied retrospectively and 27 prospectively; renal biopsy was obtained in 4, fat-tissue needle aspiration for amyloidosis in 20, and tubular function was tested in ten. Mild proteinuria and/or haematuria was found in 33 patients, the severity increasing during erythema nodosum leprosum reactions, but without overt nephritic or nephrotic syndrome. Two patients had renal amyloidosis on biopsy and two more were confirmed by fat biopsy, a 10.5% incidence in those studied prospectively; all but one were of the lepromatous type, with frequent bouts of erythema nodosum leprosum. The two other renal biopsies showed mesangial glomerulonephritis, and one unexplained acute tubular necrosis; none had immune deposits by immunofluorescence. Proximal acidification was always normal, distal acidification tested by bicarbonate infusion was abnormal in one of nine patients, and six of nine patients had concentration defects. Leprosy causes frequent urinary sediment changes and concentration defects, usually without clinical expression; proteinuria and/or glomerular involvement is mainly due to amyloidosis.

Adolescent

Water immersion in an anuric cirrhotic patient.

An anuric ESRD patient on chronic hemodialysis with liver cirrhosis and refractory ascites was treated with ultrafiltration followed by head-out water immersion (HWI) and a new period of ultrafiltration. Despite anuria and the absence of peripheral edema, 4 h of HWI significantly raised the central venous pressure, diminished the abdominal girth by 5%, and successfully transfered at least 2.4 liters of ascitic fluid to the intravascular space made available to ultrafiltration. Dialysis or ultrafiltration alone were not effective in removing this amount of fluid or in reducing ascites.

Ascites

[Value of aspiration biopsy of subcutaneous fat in amyloidosis].

Fine-needle aspiration of subcutaneous fat (FNAF) was performed in 24 patients, 12 with previously diagnosed amyloidosis presenting with proteinuria or nephrotic syndrome, and 12 presenting a nephrotic syndrome without amyloidosis on renal biopsy. FNAF was positive in 10 of 12 patients with amyloidosis (sensitivity: 83%) and negative in 12 of 12 patients with non-amyloid nephrotic syndrome (specificity: 100%). Considering a 2.5 to 10% prevalence of amyloidosis in adult patients with proteinuria or nephrotic syndrome, a positive FNAF is diagnostic of amyloidosis, and a negative FNAF rules out the diagnosis with a probability of 98 to 99%. FNAF is a simple and safe method which can be useful in patients who cannot undergo a renal biopsy.

Adipose Tissue

Connective tissue biomatrix: its isolation and utilization for long-term cultures of normal rat hepatocytes.

A new procedure is introduced for the isolation of connective tissue fibers, called biomatrix, containing a significant portion of the extracellular matrix (basement membrane components and components of the ground substance). Biomatrix isolated from normal rat liver contains >90% of the tissue's collagens and all of the known collagen types, including types I and III and basement membrane collagens. The purified collagenous fibers are associated with noncollagenous acidic proteins (including fibronectins and possibly small amounts of glycosaminoglycans). Procedures are also described for preparing tissue culture substrates with these fibers by either smearing tissue culture dishes with frozen sections or by shredding the biomatrix into small fibrils with a homogenizer. The biomatrix as a substrate has a remarkable ability to sustain normal rat hepatocytes long-term in culture. The hepatocytes, which on tissue culture plastic or on type I collagen gels do not survive more than a few weeks, have been maintained for more than 5 mo in vitro when cultured on biomatrix. These cells cultured on rat liver biomatrix show increased attachment and survival efficiencies, long-term survival (months) and retention of some hepatocyte-specific functions.

Animals