Inborn errors of metabolism: an update on epidemiology and on neonatal-onset hyperammonemia.

Inborn errors of metabolism (IEM) are a highly heterogeneous group of genetic conditions and represent a relevant cause of morbidity and mortality in the pediatric population. IEM, which are individually rare but collectively numerous, are well-recognized entities of the generic class of "rare" diseases. Since the first descriptions by Garrod at the beginning of the 20th century, several hundred new disorders have been defined, as new biochemical and molecular diagnostic tools became available. The clinical pictures of single diseases are extremely diverse, ranging from acute life-threatening manifestations to chronic late-onset forms, with single or multiorgan involvement. Mental retardation and progressive neurological impairment often characterize the clinical course. One of the principles to prevent high morbidity and mortality rates is early recognition followed by prompt therapeutic intervention. Therefore, a small number of treatable IEM is subject to neonatal mass screening. More recently, an innovative technique, based on tandem mass spectrometry, has expanded the range of neonatal screening to several additional disorders. Owing to the extreme heterogeneity, as well as to the increasing number of new disorders, exhaustive and updated epidemiological data on the overall occurrence of IEM are lacking. A national retrospective study was conducted to define the epidemiological profile of IEM in Italy and to estimate the costs related to the disease burden. Other relevant issues of our investigations focused on creating protocols of treatment for neonatal IEM, and on the development of new methods for the biochemical diagnosis.

Chronic myelogenous leukemia following kidney transplantation in a pediatric patient.

The incidence of cancer is increased follow- ing kidney transplantation. Chronic myelogenous leukemia (CML) has been previously reported in ten adult patients and only one pediatric patient post kidney transplantation. We report one male patient aged 18.8 years, on chronic dialysis from the age of 2 years, who was transplanted from a cadaver donor at the age of 8 years. He was treated with recombinant human growth hormone (rhGH) before transplantation and with azathioprine after kidney transplantation. Eight years after transplantation, CML was diagnosed and he was successfully treated with hydroxyurea and alpha-interferon. The follow-up is 28 months. The possible role of the combined action of rhGH and azathioprine in CML genesis is discussed.

Extracorporeal dialysis in neonatal hyperammonemia: modalities and prognostic indicators.

We investigated the prognostic indicators in ten hyperammonemic neonates: four treated by continuous arteriovenous hemodialysis (CAVHD), four with continuous venovenous hemodialysis (CVVHD), and two with hemodialysis (HD). Plasma ammonium levels decreased significantly within the first 24 h irrespective of dialysis modality (from 1419 to 114 micromol/l, median values; P<0.0001). CVVHD achieved the highest ammonium clearance. HD provided highest ammonium extraction but clearance was hampered by severe hemodynamic instability. Five patients had a good outcome (normal at follow-up of 9-59 months), five had poor outcome (four died and one has severe neurological damage). Total coma duration was shorter in patients who had a good outcome (47+/-11 vs 78+/-13 h; P=0.02). Remarkably, only coma duration before dialysis determined this difference (22.2+/-10.1 vs 48.8+/-11.2 h; P=0.02). In cases with good outcome, coma duration was <33 h, whereas the others exceeded this limit. The prognosis was not related to dialysis modality, rapidity in reducing ammonium levels or to the underlying metabolic defect. In conclusion, results showed CVVHD to be the optimal modality for extracorporeal ammonium detoxification. However, the most relevant indicator for prognosis was coma duration before the start of dialysis. Therefore, major efforts should be made to refer patients quickly to highly specialized centers.

Hyperparathyroidism during growth hormone treatment: a role for puberty?

We describe three adolescent patients on chronic hemodialysis with a pubertal growth spurt who developed severe hyperparathyroidism during recombinant human growth hormone treatment. Parathyroid hormone levels were raised in parallel with the increase in linear growth in all patients. In two patients, hyperparathyroidism was successfully controlled with an increase in calcitriol dosage. In the third patient, growth hormone had to be withdrawn. We discuss the possibility that puberty is a risk factor for the development of hyperparathyroidism during growth hormone therapy.

A ten-year experience of Brescia-Cimino arteriovenous fistula in children: technical evolution and refinements.

PURPOSE: The arteriovenous fistula (AVF) of Brescia-Cimino fulfills nearly all of the criteria for an optimal access for chronic hemodialysis, such as long-term patency rate, low complication rate, and respect of vascular morphologic features. Alternative dialytic methods (i.e., external shunts and vascular grafts) cannot easily be applied to pediatric patients, and in addition, these methods are responsible for higher complication rates. METHODS: From January 1985 to December 1994, 112 Brescia-Cimino AVFs were performed in 90 children (average age, 5.5 years; range, 5 months to 18 years). The average weight of the children was 28 kg (range, 6.5 to 54 kg); 16% of AVFs were performed in children who were less than 5 years old, and 18% in children who were less than 15 kg in body weight. RESULTS: Chronic renal failure was caused by a nephropathy in 53 cases (14 with a nephrotic syndrome), and 37 cases had a uropathy. In all cases a phlebography was performed before the microsurgical treatment. Since 1994 an inflatable tourniquet has been placed on the selected upper arm because of an optimal exsanguination of the operating field. The primary patency rate was obtained in all but six of the children; 35% of AVFs had either immediate or late complications. Thrombosis was the most frequent complication that we observed. In comparison with 79% of late thrombosis, 60% of early thrombosis was cured. Of the 80 AVFs, 63.5% with a 4-year follow-up are still patent. CONCLUSION: We emphasize the following two conclusions: first, microsurgery is essential to create AVFs with good results in children as well as in adult patients; and second, the results improved after the adoption of an upper-arm exsanguination and ischemia (pressure range, 400 mm Hg to 600 mm Hg) that avoided spasm of the vessels with a final 35% reduction in surgical time.

Risks of acute renal failure after cardiopulmonary bypass surgery in children: a retrospective 10-year case-control study.

To our knowledge there are no case-control studies that have examined the main risk factors for acute renal failure (ARF) following cardiopulmonary bypass surgery in children. We therefore evaluated the potential risk factors in a large retrospective case-control study. Sixty-one of 2262 children (2.7%) developed postcardiopulmonary bypass surgery ARF requiring peritoneal dialysis (PD) from 1982 to 1991. Fifty-eight of 61 cases (median age 8.5 months) were selected by systematic sampling and matched with 176 controls who did not develop ARF. The four matching variables were age, cardiopulmonary bypass and circulatory arrest duration, and year of operation. Mortality rate was 79% in cases (controls: 18%). Forty-three of 48 of the deceased cases did not recover renal function: no renal cause of death was found; 13 of 61 cases survived and recovered renal function. Multiple regression analysis showed the following significant risk factors for postcardiopulmonary bypass surgery ARF: central venous hypertension > 12 h (odds ratio (OR) 9.6); systolic arterial hypotension > 12 h (OR 8.9); dopamine dosage > 15 micrograms/kg/min (OR 3.0); adrenaline (OR 5.9) and isoproterenol (OR 13.5) use. High preoperative serum creatinine, cyanosis, and vasodilator use were not significant risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

[Isolation of Listeria seeligery from cecum of vizcacha (Lagostomus maximus maximus)]. / Aislamiento de Listeria seeligeri de ciego de vizcacha (Lagostomus maximus maximus).

Recent food listeriosis outbreaks confirm that more faithful isolation and identification methods for Listeria monocytogenes or other potentially pathogen microorganisms are required. Furthermore, the human and animal reservoir role in the ecology of this disease must be established. Listeria spp. in the vizcacha intestinal content was determined by two isolation procedures, starting from 10 g of homogenized samples in 40 ml of PBS. I)0.1 ml was stripped on phenylethanol agar, selective agar for Listeria and acryflavin ceftazidin agar, then incubated at 37 degrees C for 48 h, suspected colonies were identified by preliminary tests (Gram, hemolysis, catalase, esculin hydrolisis and motility at 22 degrees C) and confirmatory tests (indol, methyl red, Voges Proskauer, nitrate and carbohydrate fermentation) (Table 1). Antibiotic susceptibility, protein profile by PAGE and pathogenic power in mice were determined. II) The remaining homogenate was incubated at 4 degrees C in 100 ml of Donnelly and Baigent enrichment broth, weekly or monthly with subcultures until 30 days or 6-8 months, respectively. The subcultures were followed up as in I). A L. seeligeri strain, susceptible to antibiotics suggested for L. monocytogenes and exhibiting resistance to some second and third generation cephalosporins, was isolated (Table 2). The protein profile of both species was coincident, but L. seeligeri was not virulent for mice. The finding of L. seeligeri in an animal (4.0%) used as human feeding source is of interest due to its potential pathogen power.

Aislamiento de Listeria seeligeri de ciego de vizcacha (Lagostomus maximus maximus) / [Isolation of Listeria seeligery from cecum of vizcacha (Lagostomus maximus maximus)]

Recent food listeriosis outbreaks confirm that more faithful isolation and identification methods for Listeria monocytogenes or other potentially pathogen microorganisms are required. Furthermore, the human and animal reservoir role in the ecology of this disease must be established. Listeria spp. in the vizcacha intestinal content was determined by two isolation procedures, starting from 10 g of homogenized samples in 40 ml of PBS. I)0.1 ml was stripped on phenylethanol agar, selective agar for Listeria and acryflavin ceftazidin agar, then incubated at 37 degrees C for 48 h, suspected colonies were identified by preliminary tests (Gram, hemolysis, catalase, esculin hydrolisis and motility at 22 degrees C) and confirmatory tests (indol, methyl red, Voges Proskauer, nitrate and carbohydrate fermentation) (Table 1). Antibiotic susceptibility, protein profile by PAGE and pathogenic power in mice were determined. II) The remaining homogenate was incubated at 4 degrees C in 100 ml of Donnelly and Baigent enrichment broth, weekly or monthly with subcultures until 30 days or 6-8 months, respectively. The subcultures were followed up as in I). A L. seeligeri strain, susceptible to antibiotics suggested for L. monocytogenes and exhibiting resistance to some second and third generation cephalosporins, was isolated (Table 2). The protein profile of both species was coincident, but L. seeligeri was not virulent for mice. The finding of L. seeligeri in an animal (4.0

) used as human feeding source is of interest due to its potential pathogen power.

Aislamiento de Listeria seeligeri de ciego de vizcacha (Lagostomus maximus maximus). / [Isolation of Listeria seeligery from cecum of vizcacha (Lagostomus maximus maximus)]

Recent food listeriosis outbreaks confirm that more faithful isolation and identification methods for Listeria monocytogenes or other potentially pathogen microorganisms are required. Furthermore, the human and animal reservoir role in the ecology of this disease must be established. Listeria spp. in the vizcacha intestinal content was determined by two isolation procedures, starting from 10 g of homogenized samples in 40 ml of PBS. I)0.1 ml was stripped on phenylethanol agar, selective agar for Listeria and acryflavin ceftazidin agar, then incubated at 37 degrees C for 48 h, suspected colonies were identified by preliminary tests (Gram, hemolysis, catalase, esculin hydrolisis and motility at 22 degrees C) and confirmatory tests (indol, methyl red, Voges Proskauer, nitrate and carbohydrate fermentation) (Table 1). Antibiotic susceptibility, protein profile by PAGE and pathogenic power in mice were determined. II) The remaining homogenate was incubated at 4 degrees C in 100 ml of Donnelly and Baigent enrichment broth, weekly or monthly with subcultures until 30 days or 6-8 months, respectively. The subcultures were followed up as in I). A L. seeligeri strain, susceptible to antibiotics suggested for L. monocytogenes and exhibiting resistance to some second and third generation cephalosporins, was isolated (Table 2). The protein profile of both species was coincident, but L. seeligeri was not virulent for mice. The finding of L. seeligeri in an animal (4.0

) used as human feeding source is of interest due to its potential pathogen power.

Energy and nutrient intake of patients with mild-to-moderate chronic renal failure compared with healthy children: an Italian multicentre study.

Nutritional counselling is important in the management of children with chronic renal failure (CRF). In 1988, a controlled European multicentre study was started to evaluate the effects of a low-protein diet on the progression of CRF in children. To assess the energy, macro- and micronutrient intake, 4-day weighed dietary records were obtained from 50 children with low to moderate CRF (creatinine clearance 65 to 15 ml/min per 1.73 m2) and from 93 healthy children. The mean energy intake was 90%-93% of the recommended dietary allowance for Italian children in controls and 76%-88% in CRF patients. The mean protein intake was 2.1-3.1 g/kg per day in controls and 1.6-2.7 g/kg per day in CRF patients. Overall, the energy intake was 10% and the protein intake 33% lower in CRF patients than in healthy children. Children with CRF consumed less cholesterol, calcium and phosphorus than healthy children. The lower spontaneous intake of energy, protein and other nutrients should be taken into account when planning the nutrition of children with CRF.

Long-term EEG monitoring in uremic children on chronic dialysis treatment.

Even in the absence of clinically apparent seizures, patients undergoing chronic dialysis often exhibit abnormal EEG activity, which is usually attributed to the type of dialysis or to the dysequilibrium syndrome. To find out whether these abnormalities occurred only during dialysis sessions, 10 children with end-stage renal failure undergoing chronic dialysis were continuously monitored for 52 h during dialysis and between two sessions. The EEG tracing was abnormal in 5 children. Two had paroxysmal aspecific slow waves towards the end of the sessions, with a fall in blood pressure, malaise and fainting. In 3 children EEG abnormalities - also present in the interdialytic period - were not clinically apparent. Long-term EEG monitoring in these cases distinguished between the electrical events that were related to dialysis and those that were not. It also suggested that, rather than being dialysis-dependent, these events frequently reflect a basic neurological disorder.

[Hemolysins of Listeria monocytogenes demonstrable by activation with 2-mercaptoethanol]. / Hemolisinas de Listeria monocytogenes demostrables por activación con 2-mercaptoetanol.

Jones and Seeliger with the endorsement of the International Committee on Systematic Bacteriology, Subcommittee on the Taxonomy of Listeria, are considering to replace L. monocytogenes ATCC 15313 as prototype strain of species because of the lack of hemolytic activity in conventional agar blood media. We demonstrate in this work that ATCC 15313 strain is able to induce hemolysis in conventional media under microaerophilic conditions and also has a definite hemolytic activity when supernatants of a 24 hs growth in brain heart infusion plus 0.5% dextrose were activated with 2-mercaptoethanol (Table 3). Thirteen strains previously identified as L. monocytogenes were studied. Nine of them are compatible with the identification of L. monocytogenes, all show hemolytic activity under microaerophilic conditions, ATCC 15313 does nos show hemolysis on surface test but induces hemolysis, as other nine strains do, when activated by 2-mercaptoethanol. It is interesting to reinforce the need to perform all the different test to analyze hemolytic activity as a basis for presumptive L. monocytogenes identification. The absence of demonstrable hemolysis using all proposed test is an important factor to be taken into account for Listeria identification.

Hemolisinas de Listeria monocytogenes demostrables por activación con 2-mercaptoetanol. / [Hemolysins of Listeria monocytogenes demonstrable by activation with 2-mercaptoethanol]

Jones and Seeliger with the endorsement of the International Committee on Systematic Bacteriology, Subcommittee on the Taxonomy of Listeria, are considering to replace L. monocytogenes ATCC 15313 as prototype strain of species because of the lack of hemolytic activity in conventional agar blood media. We demonstrate in this work that ATCC 15313 strain is able to induce hemolysis in conventional media under microaerophilic conditions and also has a definite hemolytic activity when supernatants of a 24 hs growth in brain heart infusion plus 0.5

dextrose were activated with 2-mercaptoethanol (Table 3). Thirteen strains previously identified as L. monocytogenes were studied. Nine of them are compatible with the identification of L. monocytogenes, all show hemolytic activity under microaerophilic conditions, ATCC 15313 does nos show hemolysis on surface test but induces hemolysis, as other nine strains do, when activated by 2-mercaptoethanol. It is interesting to reinforce the need to perform all the different test to analyze hemolytic activity as a basis for presumptive L. monocytogenes identification. The absence of demonstrable hemolysis using all proposed test is an important factor to be taken into account for Listeria identification.