Isolation of human alpha-fetoprotein in two fractionation steps and demonstration of homogeneity

Human alpha-fetoprotein (hAFP) has been isolated from cord serum in 40% yield using an isolation procedure consisting of only two major steps: affinity chromatography followed by preparative polyacrylamide gel electrophoresis (PAGE). The final product appeared homogeneous on the basis of five independent criteria for purity. Sodium dodecyl sulfate gel electrophoresis (SDS-PAGE) demonstrated a single polypeptide chain with molecular weight of 71,000. The protein exhibited an apparent isoelectric point (pI') of 4.85, molecular radius of 3.0 nm and a valence (net H+/molecule) of 21.9 derived from computation of analytical PAGE data. The two-step isolation procedure made it possible for a single operator to isolate milligram amounts of hAFP in a matter of weeks.

Continued pregnancy after failed first trimester abortion

Forty-six patients with unintentional continued pregnancy were detected among a series of 65,045 first trimester abortions. Patients at greatest risk are those with very early pregnancy and those with marked uterine anteversion or retroversion or with uterine anomaly. Attention to gestational duration and uterine size as related to the amount and character of the evacuated tissue, particularly stressing identification of villi and fetal tissues, may help avoid this problem.

Small stable RNAs from Escherichia coli: evidence for the existence of new molecules and for a new ribonucleoprotein particle containing 6S RNA

Small stable RNA molecules of Escherichia coli other than 5S (rRNA) and 4S (tRNA) were studied. Two of the molecules corresponded to 4.5S and 6S RNA, which have been reported previously. The third stable RNA molecule, 10S RNA, has not been described before. RNA labeled with (32)P(i) or [(14)C]uracil for a relatively long time, when separated in 5%/12% tandem polyacrylamide gels, displayed three bands corresponding to 10S, 6S, and 4.5S RNA in addition to rRNA and tRNA bands. These RNAs were stable in pulse-chase-labeling experiments. The amount of these RNAs was small, comprising only 0.2 to 0.5% of the total (32)P incorporation. However, this amount represented a large number of molecules; for 6S and 4.5S, it was about 1,000/DNA molecule. These three RNAs were found in the postribosomal supernatant fraction. None of them was found in purified nucleoid fractions in which the tightly coiled DNA molecules were contained. Of these three RNAs, 6S RNA was unique in that it seemed to exist in a ribonucleoprotein particle. All these RNAs, as well as tRNA, were very stable in the cell under various physiological conditions. 5S RNA was less stable. On the other hand, purified 6S RNA was more susceptible than tRNA to cell nucleases when incubated with cell extracts, suggesting that, being in a particle, it is protected from cell nucleases.

A comparative study of the effect of oxantel-pyrantel suspension and mebendazole in mixed infections with Ascaris and Trichuris

A comparative trial was carried out in 4 orphanges in Seoul, to compare the anthelminthic efficacy of oxantel-pyrantel suspension and mebendazole tablets against mixed infections of Ascaris lumbricoides and Trichuris trichiura. 40 patients were divided into 4 groups and received oxantel-pyrantel suspension at 15 or 20mg/kg once only or on 2 consecutive days. Another group of 20 patients was treated with 100mg of mebendazole twice a day for 3 days. Both drugs achieved a 100% cure rate for Ascaris infections. Against Trichuris infections, the average cure rate and egg reduction rate of oxantel-pyrantel treated groups was 87.5% and 92.3% respectively, and that for mebendazole was 65% and 89.1%. There were no side-effects. The results of the present study suggest that oxantel-pyrantel is more effective in the treatment of mixed infections of Ascaris and Trichuris, and was more acceptable to the patients, than mebendazole.

Evidence of a specific nidation site in ruminants

The site of umbilical cord attachment in ruminants indicates the limited segment of the uterus where the blastocyst attachment occurs and could have potential significance for locating presumptive nidation sites. Measurements of the site of cord attachment were made on impala (Aepyceros melampus) and common duiker (Sylvicapra grimmia) at several stages of gestation. Both implant only in the right uterine horn although they ovulate from either ovary. Relative to uterine length, cord attachment in impala is somewhat closer to the cervix than it is in common duiker. As pregnancy advances in common duiker, the relative position of cord attachment becomes closer to the tubal end. This relationship was not seen in impala and may perhaps to be attributed inadequate data. Upon extrapolation of the data from common duiker, a presumptive attachment area is suggested for this species. This region is located at about 41% of the distance from the internal cervical os to the uterotubal junction. Similar cord attachment data could be used in any ruminant species to indicate the existence and location of a specific nidation site.

Histidase activity in cultivated human amniotic fluid cells

Epithelial and fibroblast cells were obtained from cultures of amniotic fluid cells. Epithelial cells demonstrated high activities of histidase. In contrast, histidase activity was not detected in fibroblasts derived from the same original culture. This observation indicates that cultures of amniotic fluid cells consist of cells with different biochemical properties as well as morphological characteristics.

A polynucleotide segment rich in adenylic acid in the rapidly-labeled polyribosomal RNA component of mouse sarcoma 180 ascites cells

The rapidly-labeled polyribosomal RNA component from mouse sarcoma 180 cells is retained on nitrocellulose (Millipore) membrane-filters at high ionic strength. This property is due to the presence of a polynucleotide sequence rich in adenylic acid that resists both T(1) and pancreatic RNase digestion. The resistant material shows sedimentation characteristics close to those of transfer RNA. The RNA molecules that contain this material can be separated from the rest of the polysomal RNA by differential phenol extraction with neutral and alkaline Tris buffers. Synthetic poly(A) exhibits the same behavior as the rapidly-labeled polysomal RNA with respect to Millipore binding and phenol fractionation. The characteristics of the rapidly-labeled polysomal RNA component permit its isolation free of ribosomal RNA.

Attachment of ribosomes to membranes during polysome formation in mouse sarcoma 180 cells

Addition of nutrients to starved mouse S-180 cells leads to rapid conversion of ribosomal monomers to polysomes. During this process, a portion of the ribosomes originally found in the 17,000 g (10 min centrifugation) supernatant of cell lysates becomes firmly attached to structures sedimenting at 500 g (5 min centrifugation). Electron microscopy of sections of the intact cells showed the change from randomly distributed ribosomal particles to clusters. Association with membranes also became evident. The material sedimenting at 500 g comprised nuclei enclosed in an extensive endoplasmic reticulum (ER) network. This fraction prepared from recovering cells showed numerous ribosome clusters associated with the ER network. The appearance of many of these clusters indicated that the ribosomal particles were not directly bound to the membranes. RNase treatment released about 40% of the attached ribosomes as monomers, and ethylenediaminetetraacetic acid released 60% as subunits. It is suggested that during polysome formation a portion of the ribosomes becomes attached to the membranes through the intermediary of messenger RNA.

Diacetyl production by Propionibacterium shermanii in milk cultures

Diacetyl production by propionibacteria in milk cultures was studied using a previously described sensitive method specific for diacetyl. Twenty-four strains belonging to six Propionibacterium species were included in the study. A strain of P. shermanii that produced relatively large amounts of diacetyl in milk was chosen for investigations on factors affecting diacetyl production.Accumulation of the diketone in milk cultures was greater at 21 C than at 32 or 37 C although the rate of production of the compound was greater at the higher temperatures. Rapid cooling after incubation stabilized the diacetyl levels in milk cultures, and prolonged refrigerated holding caused an increase in the concentration of the flavor compound. The dicarbonyl production was greatly affected by the pH of the culture medium, the most favorable range being 4.0 to 4.5. In mixed culture study using a homo-fermentative Streptococcus lactis in combination with the P. shermanii strain, diacetyl production by the latter was greatly enhanced by the rapid pH depression brought about by the streptococci. Diacetyl reductase assays on cell-free extract preparations from the P. shermanii strain showed little or no activity.