Effect of chronic administration of different Bence Jones proteins on rat kidney

The role of Bence Jones proteins (BJPs) in the genesis of the renal dysfunction that develops in patients with multiple myeloma is not clearly defined. We previously evaluated renal function and morphology in a unique strain of rats (LOU/m) bearing tumors which synthesized BJPs with isoelectric points of 5.2, 4.3 and 6.7. Myeloma cast nephropathy developed in one tumor bearing group (pI 5.2), tubular necrosis was observed in another (pI 4.3), and renal function and histology remained normal in a third group (pI 6.7). To see if these renal outcomes were a function of the BJP being excreted or other factors which could be present in the tumor bearing animals, we have examined the effect of chronic intravenous administration of these three BJPs on renal function and histology in non-tumor-bearing LOU/m rats. Urine containing the BJP was collected from tumor bearing rats, sterilized by passage through a 0.2 mu millipore filter, concentrated to 50 mg/ml, and dialyzed extensively so as to remove material with a molecular weight less than 3500. Chronic indwelling-venous catheters were placed in non-tumor-bearing LOU/m rats and these rats were given 100 mg/day for five days of one of the three BJPs. Polyfructosan clearance (Cin) was measured prior to and following the five days of BJP administration. Renal histology was examined at the completion of the second Cin. In the pI 5.2 group (N = 6), a severe distal nephron cast nephropathy occurred and Cin fell from 2.88 +/- 0.24 to 0.90 +/- 0.17 ml/min (P less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)     

Spermidine synthase of Escherichia coli: localization of the speE gene.

We have obtained Escherichia coli mutants lacking spermidine synthase (putrescine aminopropyltransferase) and have found that the mutated gene (speE) is located immediately upstream from the gene coding for S-adenosylmethionine decarboxylase (speD); these genes are located at 2.7 minutes on the E. coli chromosome. Both genes are present in a 1795-base-pair fragment of E. coli DNA that was cloned into pBR322. Deletion of 105 bases upstream of speE caused a coordinate loss of both activities, indicating that speE and speD constitute a single operon. speE and speD have also been cloned separately in a high-expression vector; strains carrying these plasmids overproduce the respective enzymes.     

Cycling program effects on one rheumatoid arthritic

These researchers investigated the effects of a progressive resistive, cycle ergometric exercise program on cardio-vascular endurance in one rheumatoid arthritic. The 46 yr. old, male subject exercised three days/week for 14 weeks. Workouts included interval-type training using 5 minute intervals for a total of 20-30 minutes (work rate set at 50-75 watts for each interval), not including 3-minute warm-up and cool-down periods (work rate set at zero resistance). Maximal exercise stress testing on the cycle ergometer was completed and blood samples collected before and after the exercise program. Also, psychological and physical health and lifestyle data were gathered before, during and after completion of the program. The conditioning program produced a training effect (greater than 75% of the HR max after the second exercise session) and blood values improved (10-28%) from the beginning to the end of the program. Finally, the program appeared to have a positive influence on various physical and psychological parameters as perceived by the subject and his wife.     

Giant axonal neuropathy: central abnormalities demonstrated by evoked potentials

Previous studies of giant axonal neuropathy have reported clinical and pathological findings that indicate involvement of the central nervous system. We studied 3 boys with giant axonal neuropathy, who were 14 to 16 years of age, using auditory, visual, and somatosensory evoked potentials. Absence of waveforms and prolongation of peak and interwave latencies were found. Abnormalities were noted in all modalities. The auditory brainstem evoked response in particular indicated a significant increase in brainstem conduction time. These studies add clinical neurophysiological confirmation of the central nervous system involvement in this disorder and may also provide a means of quantitative evaluation of its progression.     

Effect of immunoglobulin depositions of glomerular sialic acids in patients with IgA nephropathy

A study of double immunofluorescence-staining of immunoglobulins and sialic acids in the glomeruli from patients with IgA nephropathy is described. Renal biopsy specimens from patients with IgA nephropathy were stained with rhodamine-labeled antihuman IgA, IgG or IgM antisera and then stained with FITC-labeled Limulus polyphemus (LPA), Tricum vulgaris (WGA) or antihuman C3 antisera. Marked positive stainings of IgA and C3 and positive binding of LPA or WGA were observed in the glomerular mesangial areas from patients with IgA nephropathy. LPA or WGA were not bound with glomerular capillary walls from patients with moderate and advanced stages of IgA nephropathy, although depositions of IgA and C3 were markedly observed in such walls. There was a significant inverse correlation between the deposition of IgA and the binding of LPA or WGA in glomerular capillary walls obtained from these patients with IgA nephropathy. The levels of proteinuria from patients with moderate and advanced stages of IgA nephropathy were significantly higher than those with minimal and slight stages of such disease. It is suggested that the decrease of sialic acids in glomerular capillary walls might be due to a deposition of IgA in some patients with IgA nephropathy. It is concluded that high levels of proteinuria might be due to the decrease of sialic acids in glomerular capillary walls from patients with moderate and advanced stages of IgA nephropathy.