Search PubMed⌕ Search

Biomedical subjects

A E Davis

Publications and source records attributed to A E Davis.

At least 145 records · Page 8Linked to original sources
PubMed1978

Membranoproliferative glomerulonephritis (MPGN type I) and dense deposit disease (DDD) in children.

A review of the histologic findings in 27 patients originally classified as having some form of membranoproliferative glomerulonephritis (MPGN) revealed 13 with MPGN Type I and 14 with dense deposit disease (DDD). In all 14 cases where electron microscopy was performed, the histologic diagnosis was confirmed. In nine cases the diagnosis of DDD was easily made in histologic sections on the basis of ribbon-like, brightly PAS positive thickening of the GBM, without "splitting" and with relatively slight mesangial proliferation. However, in five cases the picture closely resembled MPGN Type I, with hypercellularity, "splitting" and only focal ribbon-like thickening of the GBM, which required oil immersion for recognition. There was no correlation between the serum C3 levels and the morphologic diagnosis: nine (4 MPGN Type I, 5DDD) had persistently low C3 levels, two (1 MPGN Tye I, 1DDD) were normocomplementemic, and in 16, the C3 levels varied. C3 levels increased with time in nearly all patients. The clinical course was similar in patients with MPGN Type I and DDD. Significant correlations between the rate of development of renal failure and sex, age of onset, nephrotic syndrome or therapy could not be made. The five year survival rate was 87%; 12 developed renal insufficiency by five years. Although morphologically distinct, these findings suggest that DDD is clinically indistinguishable from MPGN Type I.

Cell Membrane↗
PubMed1977

Mesangial proliferative glomerulonephritis with irregular intramembranous deposits. Another variant of hypocoplementemic nephritis.

Two patients with a persistent mesangial proliferative glomerulonephritis and reduced serum C3 levels have been followed for six and 10 years. Both have had a mild course with normal renal function and spontaneous morphologic improvement. Levels of the fourth component (C4) and second component (C2) of complement, and properdin factor B have been normal; the third component (C3) of complement nephritic factor has not been detected. Ultrastructurally, irregular intramembranous electron-dense deposits are present, primarily within the lamina densa. These deposits are separated by varying lengths of normal-appearing glomerular basement membrane. Intramembranous and subendothelial electron-lucent areas, containing vesicles, are also seen. Subendothelial deposits, mesangial interposition, splitting of the glomerular basement membrane and ribbon-like intramembranous deposits are not found. The disease in these patients was clinically indistinguishable at onset from mrmbranoproliferative glomerulonephritis (MPGN). The possibility of a variant with mild clinical course, no progression and spontaneous morphologic improvement is important in planning and assessing treatment programs in this disease group.

Adolescent↗
PubMed1977

Fundamental nature of human infant's brain asymmetry.

Morphological speech zone asymmetry in man cannot be due to environmental or developmental factors after birth. The functional implication of such a finding is not yet clear. Morphological asymmetry of the human brain is paralleled by electrophysiological evidence of cerebral hemispheric asymmetries. The results of our analysis of 50 infants suggest that clear occipital-temporal coherency asymmetry similar, but not identical to the adult pattern, also exists at or near birth. These asymmetries are generated by stimuli with no verbal content and in infants who presumably have no or an undeveloped capability for language. It is suggested that language is only a part of much more fundamental asymmetries which include the processing of auditory and visual information. Our results, and those of other, are consistent with the assumption that the left hemisphere is more able to relate stimuli to past experience, either short or long-term, while the right hemisphere is more able to process, stimuli which are not easily identifiable or referable. These capabilities would not be based on language, and hence would be expected to develop independently and possibly before speech. The demonstration that reversing electrophysiological asymmetries can be generated with non-speech stimuli in the visual and auditory modalities, and in neonates, supports such an assumption.

Acoustic Stimulation↗
PubMed1977

Heterogeneity of nephritic factor and its identification as an immunoglobulin.

Complement C3 nephritic factor (NeF) produces alternative pathway-meciated C3 cleavage by binding to and stabilizing the alternative pathway C3 convertase, C3bBb. Some studies have suggested that NeF is an immunoglobulin, while others conclude that it is a distinct serum protein. The heterogeneity of NeF was evaluated by electrophoresis and isoelectric focusing of NeF-containing serum followed by hemolytic demonstration of NeF activity in agar gel. With each method, diffuse cathodal zones or multiple bands of hemolysis developed, which revealed remarkable variations in patterns from patient to patient. NeF activity was absorbed by and eluted from insolubilized antibody to Fc and Fab fragments of IgG. Immunoabsorption of six NeF-containing sera with insolubilized anti-kappa and anti-lambda light chain antisera revealed that NeF had kappa antigenic determinants in three, lambda antigenic determinants in one, and both kappa and lambda antigenic determinants in two. These data indicate that NeF is an oligoclonal immunoglobulin. Because NeF binds to the alternative pathway C3 convertase, C3bBb, we suggest that it is an antibody to a conformational antigen of the C3-factor B complex, and thereby stabilizes this complex.

Complement C3↗
PubMed1977

Nippostronglylus brasiliensis infection in the rat: effect of iron and protein deficiency and dexamethasone on the efficacy of benzimidazole anthelmintics.

Malnutrition, anaemia, and gut parasites are commonly interrelated. Using the Nippostrongylus brasiliensis-rat model, the effect of iron and protein deficiency on the efficacy of benzimidazole anthelmintics was studied. It was demonstrated that the anthelmintics mebendazole and fenbendazole were significantly less effective in eradicating parasites when animals were deficient in iron and protein. This decreased efficacy of anthelmintics in iron and protein deficiency could not be overcome by intraperitoneal administration of the drug. Since nutritional deficiencies may act via impairment of the immune response, anthelmintic efficacy was determined in adequately nourished rats treated with the immunosuppressive drug dexamethasone. A similar decrease in efficacy of mebendazole was shown when these animals were treated with dexamethasone. Thus it is possible that lowered anthelmintic efficacy in iron and protein deficient animals is mediated by immune deficiency. These findings may be relevant to anthelmintic programmes in malnourished communities.

Animals↗
PubMed1977

Effect of iron and protein deficiency on the expulsion of Nippostrongylus brasiliensis from the small intestine of the rat.

The relationship between iron deficiency and protein deficiency and infestation of the rat with the nematode Nippostrongylus brasiliensis was investigated. There was a significant delay in the expulsion of N. brasiliensis from the small intestine of both iron deficient and protein deficient animals and those with a combined deficiency of iron and protein. Iron repletion returned the time of worm expulsion to normal and this would appear to be related to iron deficiency per se rather than to anaemia. Antibody initiated damage to worms was normal in the control animals and in animals with nutritional deficiencies. This suggests that the defect in worm expulsion occurs either in the cell-mediated immune system or in one of the other mediators of expulsion. Extrapolation to the human situation has important therapeutic implications in that iron and protein deficiency may play an important role in the perpetuation of helminth infestations. Thus, to be successful antihelminth therapy should be accompanied by iron and protein supplementation.

Ancylostomatoidea↗
PubMed1977

Double-blind trial of cholestyramine in post-vagotomy diarrhoea.

The effect of cholestyramine in post-vagotomy diarrhoea has been assessed under double-blind conditions. Cholestyramine produced a significant improvement in frequency, urgency, and consistency of stool as well as episodic diarrhoea. Faecal bile acid excretion was significantly higher in the post-vagotomy group when compared with normal controls. These findings confirm the effectiveness of cholestyramine and support the concept of a bile acid mediated aetiology in post-vagotomy diarrhoea.

Bile Acids and Salts↗
PubMed1977

Lateralisation of speech dominance by spectral analysis of evoked potentials.

A computerised evoked potential test for the lateralisation of speech dominance was compared with the intracarotid sodium amylobarbitone test in 22 epileptic patients. Based on spectral analysis, the computer test correctly predicted the speech dominance of 15 of 16 left speech dominant and five of six right speech dominant patients. This non-invasive test is simple, quick, and innocuous and can be easily implemented on a small laboratory computer.

Adolescent↗
PubMed1977

Biosynthesis of the third component of complement (C3) in vitro by monocytes from both normal and homozygous C3-deficient humans.

Human monocytes synthesized the third component of complement (C3) up to 5 wk in vitro. Evidence for net C3 synthesis was based on (a) incorporation of 14C-labeled amino acids into C3 protein, (b) indentity of the allotype of C3 produced in vitro with that of the doner's serum C3, even in the presence of carrier C3 protein of a different allotype; (c) correspondence of electrophoretic mobility, size, and subunit structure of C3 protein produced in vitro with serum C3; (d) inhibition of C3 production with cycloheximide. Monocytes from two unrelated C3-deficient patients were studied under conditions that supported C3 synthesis by normal monocytes. Serum from each of the patients contained less than 1% of the normal C3 concentration, buth their monocytes produced C3 at approximately equal to 25% of the normal rate when studied after 2 wk in vitro. The C3 produced in vitro by monocytes from one of the patients had the molecular weight of normal serum C3 and dissociated appropriately under reducing conditions. Monocytes from C3-deficient patients could not be distinguished from normals on the basis of morphology, rosetting with C3-coated erythrocytes, or rates of C2, and total protein synthesis.

Blood Proteins↗
PubMed1977

Evaluation of the Honeywell ACS 1000.

The Honeywell ACS 1000, an automated computerized scanning system, is evaluated against the recommended manual method for WBC differentials. Over 400,000 data points were gathered by both methods during an 11-month study, employing routine peripheral blood smears and critically characterized control preparations. These data were found to exhibit an effective increase in throughput, precision, comparable accuracy, and a reduction in operator fatigue. In addition, the instrument demonstrates application to the improvement of quality control, teaching, and continuing education.

Computers↗
PubMed1977

Frequency and etiology of gross hematuria in a general pediatric setting.

Since the frequency of gross hematuria in general, unselected, pediatric outpatient settings has not been reported, we reviewed all patients with this symptom or sign at a pediatric emergency walk-in clinic during 24 consecutive months. Of a total of 128,395 patient visits, gross hematuria was proven in 158 (1.3/1,000 visits). Fifty-six percent of all patients had readily apparent causes for their gross hematuria. Twenty-six percent of all hematuric patients had documented urinary tract infections, but only 9% had apparent glomerular disease.

Adolescent↗
PubMed1977

Complement activation in semisolid media: insolubilization of alternative pathway convertases in agar gels with C3 nephritic factor-containing sera.

It was previously shown that when normal human serum and purified properdin or serum containing nephritic factor were allowed to diffuse toward each other in agar, a stainable precipitin line formed only in the presence of an intact alternative pathway. In the present study we have shown that when guinea pig erythrocytes were incorporated in agar and normal human serum was allowed to diffuse toward C3 nephritic factor-containing serum, a line of hemolysis appeared that coincided with the stainable line. The line of hemolysis only formed in the presence of C3, factor B and Mg++, as does the properdin or C3 nephritic factor-induced stainable line. When C2-deficient serum was incorporated in agar with guinea pig erythrocytes and serum samples containing nephritic factor were applied in wells, rings of lysis developed, the areas of which correlated significantly with nephritic factor activity. When partially purified nephritic factor (contaminated only with IgG) or serum containing nephritic factor was subjected to electrophoresis in agar-guinea pig erythrocyte gels and overlaid with normal human serum, bands of lysis developed that required factor B and C3. Lysis of guinea pig erythrocytes in this system appears to be due to insolubilization of alternative pathway convertases with activation of the membrane attack unit C5-C9.

Complement C3↗
PubMed1976

Iron fortification of milk powder.

The bioavailability of an iron-fortified full cream milk preparation was studied and found to be effective for supplementation of the diet with iron. It consequently could be of value in the prophylaxis against iron deficiency and serve as an additional source of dietary protein.

Animals↗