Rapid and early determination of sex using trophoblast biopsy specimens and Y chromosome specific DNA probes.

The feasibility of determining sex by analysing deoxyribonucleic acid (DNA) with two probes specific for Y chromosomes was shown using DNA obtained from samples of blood from 30 non-related males and females of different ethnic origin. The DNA was spotted on nitrocellulose filters and hybridised with both a repetitive (P1) and a unique (49f) sequence specific for the human Y chromosome. A strong positive signal with both probes indicated the presence of male DNA. The sex of 12 fetuses was then similarly determined by molecular characterisation of DNA from trophoblast biopsy specimens. Chorionic samples were obtained in seven cases before termination of pregnancy in the first trimester and the aborted embryos subjected to karyotyping and sex chromatin analysis. In the five other cases samples were obtained from placentas obtained during caesarean section. Results of hybridisation were compared with those from cytogenic studies and actual sex at birth. The sex of all 12 fetuses was determined correctly by hybridisation.     

Effect of treatment with the MER tubercle bacillus fraction on syngeneic plasma cell tumors of BALB/c mice

Summary MER administered prophylactically prolonged the survival of BALB/c mice challenged with transplants of syngeneic plasmacytomas to a moderate but significant extent. In contrast, MER exerted little therapeutic action when given alone at or after tumor implantation.Combined treatment, with MER introduced prophylactically and cyclophopshamide (CY) after tumor implantation, decreased the incidence of recurrence of one of the tumors tested (MPC-11 NP, a non-myeloma protein producer) and prolonged host survival significantly as compared with animals subjected to CY therapy alone. When, instead, MER was introduced at the time of tumor challenge or thereafter to animals also treated with CY, the therapeutic response was not appreciably different from that of mice under therapy with CY only. With regard to the second plasmacytoma (MPC-11 P, a myeloma protein producer), mice treated with CY and given MER prior to or after challenge showed similar responses to animals given chemotherapy only; when MER was injected at the time of challenge and CY thereafter, the chemoimmunotherapy was somewhat inferior to chemotherapy alone.This work was supported by US Public Health Service Contract NO1-CM-12127, and by grants from Mrs. J. H. Hazen, Ruth Estrin Goldberg Memorial for Cancer Research, Leukemia Research Foundation, Inc., Concern Foundation, Inc., and Mr. and Mrs. M. Gordon     

Separation of RRBC-RFC and non-rosette forming cells (non-RFC) of guinea pig T-cell populations and their functional difference. 1. Response of RRBC-RFC and non-RFC to either Con-A or LPS.

Guinea pig lymph node cells suspension (LNC-O) was filtered through a glass wool column and the effluent (LNC-G) was further filtered through a nylon column. In this effluent (LNC-NE) about 30 per cent of the lymphocytes was identified as non-rosette forming cells (non-RFC). The non-RFC fraction was separated from LNC-NE fraction by Ficol-Conray specific gravity centrifugation or effluent cells reacted previously to rabbit red blood cells (RRBC). The upper layer after centrifugation, designated non-RFC fraction, was separated. In this fraction 96% of the cells were lymphocytes and about 95% of them were non-RFC, which lacked receptors for rabbit red blood cells (RRBC) or EAC and detectable surface immunoglobulin by conventional techniques. Though the response of the lymphocytes in the non-RFC fraction to mitogenic (Con-A, LPS) or antigenic stimulation was lower in comparison with that in RFC-rich fraction, the response of non-RFC to ConA exceeded the response to LPS. These facts suggest that at least a portion of the non-RFC may be cells from the T-cell line.     

Diagnosis of pseudomembranous colitis.

Twenty-eight patients with histologically proved pseudomembranous colitis have been seen in one hospital since July 1975. All patients with the disease had received antibiotics, six for infections not requiring operations; the other 22 cases all occurred after major surgery. All the patients had diarrhoea; six patients also had fever with clinical signs of sepsis, and three had abdominal pain thought to be due to anastomotic dehiscence after colonic resection. Pseudomembranous colitis was associated with white blood counts over 15 000/mm3 in 17 patients and albumin concentrations of less than 30 g/1 in 18. Pseudomembranous colitis was an incidental finding at necropsy in two of six patients who had not had an operation. Of the 22 patients who had had major surgery, nine died from this complication; in all except two of these cases the diagnosis was made only at necropsy. If pseudomembranous colitis is suspected on clinical grounds or if there is an unexplained complication after colorectal surgery repeat sigmoidoscopy and testing for faecal toxins should be carried out to establish the diagnosis so that prompt supportive treatment can be given.     

THE DIFFERENTIATING ABILITY OF RAT LENS EPITHELIAL CELLS IN CELL CULTURE

Dissociated cells of lens epithelia of adult rats were monolayerly cultured in vitro. After about 15–20 days' period of active cell growth, such characteristic structures that correspond to "lentoid bodies" described previously in chick cultures were formed. These structures consisted of elongated cells, ultrastructural profile of which was similar with lens fiber. The presence of gamma-crystallin, a marker molecule specific to mature lens fiber, was confirmed in these elongated cells by means of fluorescent antibody technique. The differentiation of lens fiber in vitro was also recognized in clones originating from single lens epithelial cells cultured at very low cell density.     

A new in vitro system for studying cell response to mechanical stimulation : Different effects of cyclic stretching and agitation on smooth muscle cell biosynthesis

An experimental model has been devised to permit morphologic and metabolic characterization of cells subjected to a range of cyclic mechanical stimuli similar to those which may prevail in blood vessel walls. A unique feature is the use of purified elastin membranes prepared from bovine aortas as extensible substrates for cell growth. Cells attached firmly to such membranes which could then be subjected to continuous stretching and relaxation or displacement without stretching by a motor coupled to a movable supporting frame. Various combinations of frequencies, amplitudes and rates of deformation have been used over extended periods with minimal fatigue or disruption of the elastin substrate. The effects of cyclic stretching on [¹⁴C]proline incorporation into protein and collagen and [³H]thymidine incorporation into DNA by rabbit aortic smooth muscle cells were distinct from those attributable to agitation without stretching, indicating that cells responded differently to these modes of stimulation. Increases in rate of protein or DNA synthesis induced by stretching were just as marked after 48 h of stimulation as they were at the outset of an experimental period. Since the system permits observations of cell response to independently variable components of pulsatile stress over extended periods and under a variety of culture conditions, it may be expected to provide new data concerning the interaction of mechanical with hormonal and genetic factors in the elaboration of connective tissue components.