Renal function in very low birth weight infants: normal maturity reached during early childhood

Development of glomerular and tubular renal function is delayed in preterm infants. To study the pattern of maturation during infancy and childhood, we re-evaluated renal function in 22 very low birth weight infants--in 14 of the infants at 18 months postconceptional age (9 months corrected age) and in the remaining 8 infants at 8 years of age. The glomerular filtration rate remained lower at 9 months corrected age than in term infants of the same postconceptional age: 82 +/- 23 versus 125 +/- 18 ml/min per 1.73 m2 (p < 0.001). At 8 years of age the glomerular filtration rate did not differ from that of healthy control subjects. Effective renal plasma flow, filtration fraction, albumin excretion, maximal concentrating ability, and kidney size determined by ultrasonography were all normal at 8 years of age. We conclude that renal function, which is markedly reduced during the neonatal period in very low birth weight infants, reaches normal maturity by 8 years of age but not by 9 months corrected age.

The molecular biology of the porcine paramyxovirus LPMV

Protein and genomic studies of a previously uncharacterized porcine paramyxovirus (designated LPMV) confirmed that it was a member of the paramyxovirus genus. The nucleotide sequences and deduced amino acids of the complete P-gene, M-gene, F-gene and HN-gene as well as the intergenic sequences have been determined. Comparative sequence analysis of the M-gene of LPMV revealed the closest relationship of LPMV was to human mumps virus with a homology of 46% and 55% at the amino acid and nucleotide levels respectively. The P-gene of LPMV is transcribed to V protein mRNA and by editing of the gene to the P protein mRNA. The LPMV P-gene has the coding capacity for an additional protein of 126 amino acids, a C protein.

The haemagglutinin-neuraminidase glycoprotein of the porcine paramyxovirus LPMV: comparison with other paramyxoviruses revealed the closest relationship to simian virus 5 and mumps virus

The complete nucleotide sequence of the haemagglutinin-neuraminidase (HN) gene of the porcine paramyxovirus LPMV, was determined from cDNA derived from viral genomic RNA. The gene was 1906 nucleotides long including a putative gene end and poly A signal. One long open reading frame was found encoding a protein of 576 amino acids with a calculated molecular weight of 63,324. The protein contains four potential N-glycosylation sites and a major hydrophobic region near the N-terminal, suggesting a membrane anchor domain. Comparison of the deduced amino acid sequence of the LPMV HN protein with that of other paramyxovirus HN proteins, revealed the highest amino acid identity to simian virus 5 of 43% and mumps virus of 41%.

Sorbinil does not prevent hyperfiltration, elevated ultrafiltration pressure and albuminuria in streptozotocin-diabetic rats

The effects of aldose reductase inhibition on kidney function were studied in rats with streptozotocin-induced diabetes mellitus. Diabetic rats were fed sorbinil (20 and 50 mg/kg) by daily gastric gavage and were compared with untreated diabetic rats and normal rats. The rats were under daily supervision with regard to blood glucose control, insulin administration and body weight. The aim was to promote continuous body growth and to maintain the blood glucose concentration at around 22 mmol/l without large day-to-day fluctuations. The renal functional changes observed in this well-established diabetic model closely resembled those reported in human Type 1 (insulin-dependent) diabetes mellitus. Sorbinil treatment completely prevented renal cortical sorbital accumulation, but did not abolish kidney enlargement or the increase in ultrafiltration pressure and glomerular filtration rate. Albumin excretion was increased to the same extent in the sorbinil-treated and in the untreated diabetic rats. We conclude that increased metabolism of glucose to sorbitol does not cause the hyperfiltration in rats with streptozotocin-induced diabetes.

The P gene of the porcine paramyxovirus LPMV encodes three possible polypeptides P, V and C: the P protein mRNA is edited

The nucleotide sequence of the P gene of the porcine paramyxovirus La-Piedad-Michoacan-Mexico virus (LPMV) was analysed. Three long open reading frames (ORFs) were found in the mRNA sense. Insertion of two G residues is necessary to obtain an ORF encoding the P protein, which gives a P protein of 404 amino acids with a calculated Mr of 42475. This form of editing was demonstrated, two non-templated G residues being added in a portion of the mRNA transcripts. The LPMV V protein, which has a conserved cysteine-rich C-terminal region, is encoded by an exact copy of the P gene. The third ORF has the capacity to encode a protein of 126 amino acids, which may resemble the C proteins found in some paramyxoviruses. The ORF starts from an AUG codon down-stream of the first AUG codon of the P/V ORF.

Differences in the E3 regions of the canine adenovirus type 1 and type 2

Sequence analysis of a region extending between the pVIII and the fiber gene of Canine adenovirus type 1 (Cav-1, Utrecht) and type 2 (Cav-2, Manhattan) was performed. The results revealed a high level of identity between the two viruses when the pVIII gene and the N-terminal part of the fiber gene were compared. The open reading frames of region E3 in of Cav-1 and Cav-2 encoded a 22 kDa and 40.7 kDa polypeptide, respectively. The Cav-1 and Cav-2 E3 region polypeptides shared conserved amino and carboxyl domains. In Cav-2 an extra sequence of about 500 nucleotides was present, appearing like an in frame insertion of foreign DNA. It can be speculated that this insertion in the E3 region contributes to the observed biological differences between Cav-1 and Cav-2.

Comparison of virus isolation, immunofluorescence and DNA probe hybridization for detection of pseudorabies virus in experimentally infected pigs

Virus isolation, immunofluorescent staining and DNA probe hybridization, three techniques for the detection of pseudorabies virus (PRV) have been compared in pigs experimentally infected with the Thailand CB-1 strain PRV. The virus isolation and DNA hybridization detection demonstrated a good correlation in detecting infection in live animals by nasal swabbing. In white blood cells an earlier detection was seen with the DNA-hybridization techniques. Consistent results with all the three techniques tested were found in organ materials as nasal mucosa and tonsils as well as in the olfactory bulb.

Changes in renal function during the development of hypertension and effects of antihypertensive treatment. A case report

Renal function was serially investigated during the development of hypertension in a 12.8-year-old girl with chronic glomerulonephritis. Clearances of inulin (CIn) and para-aminohippuric acid (CPAH), filtration fraction, and sodium excretion were measured during hydropenia and isotonic saline volume expansion. Blood pressure was initially labile, but after a few years fixed hypertension developed, and antihypertensive treatment with propranolol was started. During the early stages of hypertension, the filtration fraction during hydropenia was reduced, but the natriuresis during volume expansion was normal. When the hypertension was fixed, glomerular filtration rate, CPAH, and filtration fraction were normal, but the natriuresis was exaggerated. Antihypertensive treatment only partially corrected the natriuresis.

Renal functional effects of prostaglandin synthesis inhibition in patients with insulin-dependent diabetes mellitus of long duration without nephropathy

The short-term effects of prostaglandin synthesis inhibition (PGSI; single dose 500 mg of naproxen) on renal function were studied in six women (age: 21.9 +/- 2.4 yrs) with insulin dependent diabetes mellitus (IDDM) of 14.3 +/- 2.8 yrs' duration, and in nine age- and sex-matched controls. The diabetics had no overt signs of nephropathy (Albustix neg, normal serum creatinine, and blood pressure). The clearance of inulin (CIn) and PAH; the filtration fraction (FF); and the excretion of Na, albumin and PGE2 were studied under water diuresis on two separate mornings, first without and then with PGSI. With PGSI all individuals has lower PGE2 excretion. The CIn and FF were significantly (p less than 0.05) higher in the diabetics than in the controls both without (129.4 +/- 23.9 ml/min/1.73 m 2 and 23.4 +/- 2.8% vs. 107.6 +/- 10.3 and 19.7 +/- 1.6) and with (133.7 +/- 29.4 and 22.6 +/- 2.1, vs. 106.8 +/- 10.3 and 20.1 +/- 1.5) PGSI. The diuresis and Na excretion were significantly lower with PGSI, than without, in both groups. The albumin excretion was significantly higher in the diabetics under both conditions (29.9 +/- 16.6 and 34.2 +/- 19.9 micrograms/min/100 ml GFR, vs. 14.5 +/- 10.6 and 12.9 +/- 8.3 in controls). We conclude that the hyperfiltration in this stage of IDDM does not appear to be PG dependent, and that PGSI does not give any immediate effects on the albumin excretion.

Course and long-term outcome of idiopathic IgA nephropathy in children

The long-term outcome of idiopathic IgA nephropathy (IgAN) in children was investigated with regard to clinical course and biopsy changes. All patients with biopsy-verified IgAN (diagnosed by kidney biopsy 1970-1985) at three children's clinics in Sweden were included in the study. Thirty-four (10 females, 24 males), out of a total of 72 patients, had a follow-up period of 8 years or more (10.7 +/- 1.9 years, range 8-14). After this duration of follow-up, urine abnormalities were found in 47% (group A), proteinuria in 35%, hypertension in 9%, and decreased glomerular filtration rate (GFR) in 3% of patients. However, 53% had no clinical signs of disease (group B). GFR depression at the time of clinical presentation of IgAN was more common in group A than in group B (P = 0.017). At the first renal biopsy, which was performed after the same duration of IgAN in both groups, focal segmental glomerular changes were more often found in group A (P = 0.017), while diffuse proliferative changes were more common in group B (P = 0.031). The course of the IgAN was thus often very protracted, with some children developing hypertension as well as decreased renal function. However, after a period of 8 years or more of follow-up half of the patients did not show any clinical signs of the disease, which may indicate low disease activity or, possibly, recovery.

Identification of the porcine paramyxovirus LPMV matrix protein gene: comparative sequence analysis with other paramyxoviruses

The complete nucleotide sequence of the gene encoding the matrix protein (M) of the porcine paramyxovirus LPMV has been determined. The gene is 1376 nucleotides long including 5' and 3' non-coding sequences with a protein-coding sequence of 1107 nucleotides. The deduced protein, containing 369 amino acids with a calculated Mr of 41,657, is hydrophobic overall with a net positive charge of +17.5. Comparative sequence analysis revealed high amino acid homology to other paramyxovirus M proteins, with the highest degree of identity (46%) with the human mumps virus. This is strong evidence that the porcine paramyxovirus LPMV is a genuine member of the paramyxovirus genus.

Plasmid profile analysis and restriction enzyme fingerprinting of Salmonella DO-group strains

In Sweden Salmonella dublin is the most common serotype within the DO-group isolated from animals. In recent years also salmonella strains belonging to the DO-group but lacking H-antigen have been isolated from cattle in different areas. It was not possible to further differentiate the latter strains by serological methods. However, all Salmonella dublin strains and those strains lacking H-antigen carried a 50 Mdal plasmid exhibiting the same EcoRI and Hind III restriction enzyme digestion pattern. Two of the 26 strains contained an additional 5 Mdal plasmid. Other serotypes within the DO-group investigated, namely Salmonella enteritidis and Salmonella panama, carried plasmids smaller than 50 Mdal. The plasmid profiles and restriction enzyme digestion patterns indicated that the salmonella strains lacking H-antigen were variants of Salmonella dublin. Thus, analysis of plasmid profile and restriction enzyme fingerprinting are useful complements to serological methods in the differentiation of salmonella DO-group strains.

Avoiding splenectomy in the treatment of children with splenic injury

Ninety-two consecutive patients with traumatic rupture of the spleen were studied. Of the first 46 children (group A), 44 underwent splenectomy. In the subsequent group (group B) non-operative management was successful in 40 of 46 patients, five patients were operated with splenic repair, and one had the spleen removed. All the ruptures were caused by blunt trauma and the severity of the splenic injury was roughly the same in the two groups of patients. A third of the patients in each group had associated injuries, renal injury being the most common intraabdominal lesion. The median hospital stay was 8.0 days (range 5 to 28) in group A and 12.5 days (range 7 to 18) in group B. Among the 40 patients who were treated conservatively, a biphasic course was seen in 23: one or two days after the accident a period of increased pulse rate, fever and increased abdominal tenderness and pain followed, but no evidence for a delayed rupture was found. Our results of conservative treatment of splenic rupture are encouraging and show that non-operative management should be considered in most cases.

Genetic drift of equine 2 influenza A virus (H3N8), 1963-1988: analysis by oligonucleotide mapping

Comparative analysis by RNA oligonucleotide fingerprints of total genomic RNA as well as the individual RNA segments of equine 2 influenza A virus strains from 1963, 1968, 1979, 1984, 1987 and 1988 revealed genetic diversity. Strains from the epizootic outbreak during 1978-1979 showed minor differences among their genomes. The Swedish isolates from 1979 up to 1988 showed increasing genomic heterogeneity indicating genetic drift.

Close relationship between mink influenza (H10N4) and concomitantly circulating avian influenza viruses

Strains of an influenza H10N4 virus have been isolated during an outbreak of a respiratory disease in mink on the south-east coast of Sweden. This was the first example of a disease in mammals caused by the H10 subtype. We compared the A/mink/Sweden/84 strain with two recent avian H10N4 isolates, one from fowl and another from a mallard, both isolated in Great Britain in 1985 as well as the prototype A/chicken/Germany/N/49 (H10N7). The comparison was carried out by genomic analysis of the strains by oligonucleotide fingerprinting and in bioassays on mink. The oligonucleotide fingerprint analysis revealed a high degree of genomic homology of around 98% between the viruses from mink, mallard and fowl. Only the recent avian isolates, that from the mallard and fowl could infect mink by contact, causing similar pathological and clinical signs and inducing seroconversion as did the mink virus. However, the susceptibility of mink to the fowl and mallard viruses by contact was less pronounced than that to the mink virus. Both the genomic homology and the similarities from the infectivity and pathogenicity studies between the mink virus and the recent avian isolates point to a direct invasion of the mink population by an avian H10N4 virus.

The structural proteins of a porcine paramyxovirus (LPMV)

The porcine paramyxovirus is a newly identified agent of a fatal disease in piglets, endemic in Mexico since 1980, where it was seen around the town of La Piedad, Michoacan, Mexico (hence LPM virus). At least six [35S]methionine-labelled proteins could be resolved by SDS-PAGE and five of them were clearly immunoprecipitated. Selective labelling of LPMV-infected cells with [3H]glucosamine revealed two bands with an Mr of about 66K and 59K, corresponding to the two viral glycoproteins, the haemagglutinin-neuraminidase protein and the fusion protein. Labelling of virus with [32P]orthophosphate disclosed one band with an Mr of 52K, corresponding to the phosphoprotein. Analysis of nucleocapsids obtained from purified virus or from a permanently infected cell line revealed one major band with an Mr of 68K, the nucleoprotein. Two other proteins were also identified, the large protein and the matrix protein, with apparent Mr of about 200K and 40K, respectively. The protein migration pattern of LPMV was compared, by SDS-PAGE, with that of Newcastle disease virus, bovine parainfluenza 3 virus and Sendai virus. Differences in the Mr of LPMV proteins and the proteins of these paramyxoviruses were observed. We propose that LPMV should be classified as a novel member of the genus Paramyxovirus.

Simplified polyacrylamide gel electrophoresis and silver staining for analysis and preparation of influenza virus RNA segments

The influenza virus has a genome consisting of eight RNA segments. A simplified technique to study the RNA segmental pattern by silver staining after gel electrophoresis has been developed. In addition, individual RNA segments could be isolated by a combination of polyacrylamide gel electrophoresis and isotachophoresis.

Cerebral abnormalities in Wilson's disease as evaluated by ultra-low-field magnetic resonance imaging and computerized image processing

The cerebral involvement of a 13-yr-old boy with Wilson's disease was serially evaluated during the first 18 mo of D-penicillamine treatment. An ultra-low-field magnetic resonance imaging (ULF MRI) system, operating at 0.02 T, with computerized image processing was used. The half-yr period prior to the clinical diagnosis was set, the patient had showed poor school performance, emotional lability, deteriorating handwriting, progressively slow, gross, and fine motor functions, and a fixed rigid smile. No overt signs of liver disease were found. With D-penicillamine treatment (1-1.5 g/d) a continuous improvement was seen. The pretreatment MRI investigation showed pronounced pathological transformation in the basal ganglia. However, changes were seen also in most other parts of the brain indicating diffuse involvement. During treatment the computerized MR images became gradually more normal. The current magnetic resonance imaging system with computerized image processing is a sensitive and simple method for evaluation of subtle parenchymal changes of the brain.

Analysis of some swine influenza H1N1 viruses by oligonucleotide fingerprinting

The genome of the swine influenza H1N1 virus Sweden/83 was compared to other H1N1 viruses by oligonucleotide fingerprinting. This analysis revealed that Sweden/83 is identical to the Danish strain Sjaelland/82 and is thus to be placed in the group of "US viruses". On the other hand, the Danish strain Als/82 was found to be different, i.e., related to the Belgium/79 strain which is a representative of the "European viruses". The results of the present genomic analysis confirm the previous findings of relationships between the above strains.

Bovine leukaemia virus ISCOMs: biochemical characterization

The glycoprotein gp51 of bovine leukaemia virus (BLV) has been included in an immunostimulating complex (ISCOM). The ISCOM was characterized biochemically in SDS-polyacrylamide gel electrophoresis showing the presence of proteins of estimated molecular weights of 50 and 30 kDa. Immunoblotting showed that gp51 was present in the ISCOM. The BLV-ISCOM had a S-value of 19 S and the electronmicrograph showed the cage-like structure as previously reported for other ISCOMs. About 17% of the total amount of gp51 in the cell culture fluid was recovered in the ISCOMs. The largest loss of gp51 was encountered during the sedimentation of the virus. An ELISA, utilizing monoclonal antibodies to defined epitopes for capture was developed to control the antigenicity of epitopes, e.g. those known to induce neutralizing antibodies. Using this device as a quality control for epitopes the following could be stated. First, ISCOMs prepared from virus solubilized with the non-ionic detergents Triton X-100 or MEGA did not react with neutralizing monoclonal antibodies. In contrast, ISCOMs prepared from virus solubilized with the non-ionic detergents Tween-20, Tween-80 or octyl glucoside did react with the neutralizing antibodies. Second, the neutralizing epitopes were better exposed in ISCOMs than the other epitopes of gp51. In a preliminary experiment it was shown that gp51 in ISCOMs was highly immunogenic.

Value of cerebrospinal fluid analysis in the differential diagnosis of meningitis: a study in 710 patients with suspected central nervous system infection

A prospective study to determine the value of cerebrospinal fluid analysis in the differential diagnosis of meningitis was performed in 710 consecutively observed patients, both children and adults, who underwent lumbar puncture due to suspected central nervous system infection. Diagnoses included acute or presumed bacterial meningitis (n = 79), acute or presumed viral meningoencephalitis (n = 218), acute unclassified meningitis (n = 6), other infections of the central nervous system (n = 37), non-infectious neurological diseases (n = 76) and control patients (n = 294). The sensitivity, specificity and predictive values were determined for cerebrospinal fluid white blood cell count, total protein, lactate, glucose and C-reactive protein levels as well as the blood/cerebrospinal fluid glucose ratio. Determination of cerebrospinal fluid levels of lactate (greater than or equal to 3.5 mmol/l) was found to be superior to the other tests. The C-reactive protein level gave no additional diagnostic information when the lactate level was determined. The white blood cell count, and total protein and glucose levels were often unreliable tools for differential diagnosis, largely due to low sensitivity at realistic discriminatory limits. The study confirms that no cerebrospinal fluid test is fully reliable in distinguishing bacterial meningitis from other forms of meningitis.

Bovine herpesvirus 1: rapid diagnosis of infection by direct filter hybridization

Direct filter hybridization (DFH) was applied as a simple method of nucleic acid hybridization to diagnose bovine herpesvirus 1 (BHV-1) infection without previous purification of nucleic acids from the specimens. The DNA of BHV-1 was cleaved with the restriction endonuclease Pst I and randomly cloned into pKH47 plasmids. The clones were labelled with 32P or biotin and selected on uninfected and infected cells for the highest specific activity to detect BHV-1 infection. Two clones, which detected about 10 infected cells, were selected for the diagnosis of BHV-1 in cattle. On specimens collected during experimental and natural disease, the DFH showed to be in concordance with the standard method of virus isolation. This simple hybridization technique proved to be a sensitive and rapid alternative to virus isolation. Specific diagnosis of BHV-1 infection can be made even in simply equipped laboratories within 10 h.

Rapid detection of Aujeszky's disease (pseudorabies) virus infection of pigs by direct filter hybridisation of nasal and tonsillar specimens

A direct filter hybridisation method has been developed to diagnose acute Aujeszky's disease in live pigs. The advantages of the method are easy, fast sample processing; no DNA-purification is needed, and the hybridisation itself is simplified. The direct filter hybridisation method has been tested on pseudorabies virus infected cultured cells, experimentally infected pigs and on specimens from an outbreak of Aujeszky's disease. Virus isolation and filter hybridisation gave comparable results, indicating that the direct filter hybridisation method is a good tool for rapid diagnosis. It is independent of cell culture facilities and the disease can be diagnosed in live animals within 15 hours.