Amniotic fluid alphafetoprotein measurements in the early prenatal diagnosis of central nervous system disorders

Amniotic fluid alphafetoprotein (AFP) has been measured in 520 pregnancies between 8 and 24 weeks of gestation. The normal range of values has been defined for fortnightly periods between these limits. Grossly elevated AFP concentrations were found in four pregnancies leading to spina bifida and nine pregnancies leading to anencephaly. Slightly elevated AFP concentrations were found in one twin pregnancy and two pregnancies affected by rhesus isoimmunisation. Normal AFP values were observed in 36 amniotic fluids from pregnancies where the outcome was rhesus isoimmunisation, an inborn error of metabolism, a cytogenetic disorder or a birth defect unrelated to the central nervous system. The reliability of amniotic fluid AFP in the early prenatal diagnosis of spina bifida and anencephaly and the possibility of performing assays on samples sent by post from any part of the world are emphasized.     

Analysis of the S(2) subsite specificities of the recombinant cysteine proteinases CPB of Leishmania mexicana, and cruzain of Trypanosoma cruzi, using fluorescent substrates containing non-natural basic amino acids

We have explored the specificity of the S(2) subsite of recombinant cysteine proteinases from Leishmania mexicana (CPB2.8 Delta CTE) and from Trypanosoma cruzi (cruzain) employing a series of fluorogenic substrates based on the peptide Bz-F-R-MCA, in which Bz is the benzoyl group and the Phe residue has been substituted for by Arg, His and non-natural basic amino acids that combine a basic group with an aromatic or hydrophobic group at the side chain: 4-aminomethyl-phenylalanine (Amf), 4-guanidine phenylalanine (Gnf), 4-aminomethyl-N-isopropyl-phenylalanine (Iaf), 3-pyridyl-alanine (Pya), 4-piperidinyl-alanine (Ppa), 4-aminomethyl-cyclohexyl-alanine (Ama), and 4-aminocyclohexyl-alanine (Aca). Bz-F-R-MCA was hydrolyzed well by CPB2.8 Delta CTE and cruzain, but all the substitutions of Phe resulted in less susceptible substrates for the two enzymes. CPB2.8 Delta CTE has a restricted specificity to hydrophobic side chains as with cathepsin L. However, the peptides with the residues Amf and Ama presented higher affinity to CPB2.8 Delta CTE, and the latter was an inhibitor of the enzyme. Although, cruzain accepts basic as well as hydrophobic residues at the S(2) subsite, it is more restrictive than cathepsin B and no inhibitor was found amongst the examined peptides.     

Effect of human colostrum and infant formula on the phagocytic activity of macrophages. I. Resident and stimulated mouse peritoneal macrophages.

Phagocytosis and degradation of radiolabelled human transferrin-anti-transferrin immune complexes by resident and stimulated mouse peritoneal macrophages was inhibited by liquid infant formula, particularly in the case of resident cells. Mouse peritoneal macrophages exposed to infant formula were shown by immunofluorescence to bind casein and beta-lactoglobulin, but there was little binding of alpha-lactalbumin. Comparison of various artificial milks, cow's milk and purified casein indicated that both the concentration and the degree of denaturation of casein may be important in the impairment of macrophage function by milk. It is suggested that bottle feeding of infants might result in impairment of macrophage function in the small intestine.     

Enhanced excitatory junction potentials in mesenteric arteries from spontaneously hypertensive rats

Excitatory junction potentials (EJPs) were examined using intracellular recording techniques in mesenteric arteries isolated from 12- to 15-week-old spontaneously hypertensive (SHR), Wistar Kyoto (WKY) and Sprague Dawley (SD) rats. The amplitudes of EJPs evoked by single supramaximal stimuli were larger in arteries from SHRs (12.9±0.7 mV,n=16) than in arteries from either WKYs (5.2±0.5 mV,n=24) or SDs (8.6±0.8 mV,n=15). The time constant of decay of EJPs did not differ significantly, suggesting that the passive electrical properties of the vascular smooth muscle are similar in the three rat strains. Spontaneous EJPs recorded in tissues from SHRs and WKYs had similar amplitude frequency distributions, suggesting that the quantal size is also similar between strains. In some arteries from SHRs, EJPs evoked by single stimuli triggered muscle action potentials (MAPs). Visible constriction only occurred following a MAP. In tissues from all three strains, summation of EJPs triggered MAPs. As EJPs are generated by the sympathetic co-transmitter adenosine 5-triphosphate (ATP), the findings of the present study indicate that purinergic transmission is enhanced in mesenteric arteries from SHRs, probably as a result of an increase in quantal release. A consequence is that when nerves are activated SHR arteries more readily undergo constriction that is dependent on voltage-activated Ca²⁺ influx.     

Acquired immunity to Salmonella typhimurium and delayed (footpad) hypersensitivity in BALB/c mice.

BALB/c mice are extremely susceptible to salmonella infections. Previous reports have suggested that this natural susceptibility is due to a defect in cell-mediated immunity (CMI) which correlates with their inability to develop a delayed (footpad) hypersensitivity reaction to a salmonella extract when immunized with attenuated salmonellae. We have shown that mice thus immunized are in fact highly resistant to superinfecting intravenous challenge with virulent organisms, at a time when the footpad test is still negative. The footpad test becomes positive 2-3 weeks later, after the appearance of CMI, which is already present at 1 week as measured by determining the fate of a superinfecting challenge in the RES. The positive footpad reactions that develop in BALB/c mice--and also in B10, and CBA and (B10XA/J)F1 mice--are transferable to normal recipients by thetasensitive spleen cells. However, although B10 mice give positive delayed hypersensitivity (DH) reactions, they are more susceptible to salmonellae of intermediate virulence than the DH negative BALB/c strain. We have also shown that previous reports which suggested that susceptible mice did not develop immunity when vaccinated with live organisms are probably due to the salmonella strain used for vaccination, which does not establish a carrier state. A strain which does establish a carrier state effectively immunizes the susceptible BALB/c strain against virulent challenge, indicating that natural susceptibility does not preclude the development of acquired immunity to reinfection. X     

In vitro phagocytic interaction betweenTrichomonas vaginalis isolates and bacteria

The phagocytic activity of 12Trichomonas vaginalis isolates against both gram-positive bacteria (Staphylococcus aureus ATCC 25923,Lactobacillus spp.) and gram-negative bacteria(Enterobacter cloacae ATCC 13047, 5 strains ofEscherichia coli, Pseudomonas aeruginosa ATCC 27853) was studied. Results showed that all the isolates were able to ingestStaphylococcus aureus to a variable degree, and almost all of them showed phagocytic activity againstPseudomonas aeruginosa. Furthermore, experiments with a restricted number of isolates ofTrichomonas vaginalis showed that they phagocytized, often very effectively, human vaginal lactobacilli. Only in some cases was the addition of serum essential for bacteria ingestion. Phagocytic uptake ofEscherichia coli andEnterobacter cloacae was not detectable under the experimental conditions used. It is concluded that phagocytosis may be involved in changes in vaginal biocenosis during the early stages of trichomoniasis.     

Role of cyclic AMP in rat aortic microsomal phosphorylation and calcium uptake.

The role of adenosine 3',5'-monophosphate (cyclic AMP)-dependent membrane phosphorylation in the regulation of microsomal calcium transport in rat aortic smooth muscle was studied. Cyclic AMP-dependent protein kinase augmented the phosphorylation of serine residues in a microsomal protein component with a molecular weight of about 44,000 (determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and the majority of 32P incorporation was in serine residue(s). The phosphorylated protein had stability characteristics of a phosphoester. The phosphorylated substrate was not extracted from the trichloroacetic acid (TCA) precipitate with organic solvents or by suspension in hot TCA; and the demonstrated hydroxylamine insensitivity suggested that the substrate was not lipid or nucleic acid. Intrinsic phosphoprotein phosphatase cleaved the labeled phosphate from the cyclic AMP-stimulated microsomes in the first 5 min of incubation. Microsomes phosphorylated in the presence of 1 micron cyclic AMP or 1 micron cyclic AMP plus 0.1 mg/ml protein kinase exhibited enhanced calcium uptake. We suggest that reversible phosphorylation of microsomal membranes may play an important role in the regulation of aortic microsomal calcium transport by cyclic AMP.     

Radio-frequency electrocautery ablation of mammary tissue in swine

PURPOSE: To establish the size, configuration, and histopathologic features of acute, subacute, and chronic radio-frequency (RF) electrocautery of mammary tissue in swine. MATERIALS AND METHODS: Eighteen RF treatments were performed in the mammary tissue of three domestic swine under ultrasonographic (US) guidance. Histopathologic examination was performed immediately after (acute animal); 2 weeks after (subacute animal); and 4 weeks after (chronic animal) treatment. RESULTS: In the acute animal, lesions were firm nodules on palpation and had a distinct line of demarcation between necrotic and viable mammary tissue (mean lesion volume, 14.24 cm(3); largest volume, 29.06 cm(3)). In the subacute animal, there was diffuse coagulation necrosis with neutrophilic infiltrates at the periphery (mean lesion volume, 6.46 cm(3); largest volume, 9.47 cm(3)), and two treatment areas had a secondary bacterial infection. In the chronic animal, lesions were still palpable and firm (mean lesion volume, 11.67 cm(3); largest volume, 25.5 cm(3)), and five of six treatment sites had an area of gray to white fibrotic tissue that blended with the surrounding tissue. However, one site had a pale yellow area of central necrosis surrounded by a fibrotic area. In both the subacute and chronic animals, two and one treatment site, respectively, had minimal areas of skin necrosis. CONCLUSION: RF ablation of breast tissue is feasible in this animal model. Problems included minimal skin erythema, residual firm treatment regions at 4 weeks, slightly variable margins of coagulation necrosis, and occasional bacterial infection.