Transport properties of rigid, symmetrical oligomeric structures composed of prolate, ellipsoidal subunits

We have calculated translational and rotational diffusion coefficients and intrinsic viscosities of oligomeric structures composed of n identical subunits having a prolate ellipsoidal shape with axial ratio p. Results are presented for p = 1-6 for a variety of structures with n = 1-6. We compare our results with those obtained by a different modeling procedure, proposed by other workers, in which the monomeric subunit is represented as a string of touching, colinear spheres. If n and an estimate of p are known, the structure of the oligomer can be. in most cases, unambiguously determined by comparison of the experimental oligomer-to-monomer ratios of a given property with the numerical results of this work. As examples of the applicability of our results, we examine the relationship between structure and properties for neurophysin. bovine serum albumin, hemoglobin and phycocyanin.     

The human thyroglobulin gene contains two 15-17 kb introns near its 3''-end.

We have cloned overlapping segments of the human thyroglobulin gene from a genomic cosmid library. Restriction mapping and electron microscopy show that a region of 38 kb at or near the 3'-end of this gene encodes only 850 nucleotides or 10% of the messenger RNA (mRNA) sequence. The region contains five exons of 130-210 nucleotides, split by introns of 1 to 15-17 kb. This represents the lowest ratio of coding to non-coding DNA (2.2%) found thus far in any eukaryotic gene. Blot hybridization under non-stringent conditions shows the presence of only one copy of this gene in the human genome and the absence of other closely related sequences.     

Lambda Ig constant region genes are translocated to chromosome 8 in Burkitt''s lymphoma with t(8;22)

By in situ hybridization of normal human chromosomes with a cloned genomic probe specific for the constant region of the lambda immunoglobulin genes, band 22q11 was preferentially labelled. In two cell lines with t(8;22) derived from Burkitt's lymphoma a strong signal was noted on the 8q+ chromosome derivative, indicating that the constant region of the lambda Ig gene cluster was translocated from chromosome 22 to chromosome 8. In addition, the signal observed on the 22q- derivative chromosome was stronger than the background in one of the two cell lines tested, but not in the other. The implications are that the break point in chromosome 22 in some cases lies within the Ig gene itself or between clusters of such genes, and that different cases have different break points.     

“Ischaemic” Colitis in Young Adults

Four cases of transient haemorrhagic colitis seen in young adults resemble 10 others in the literature. The 14 cases are distinguished from the classical transient ischaemic colitis syndrome by their youth, the low incidence of stricture formation, and the prevalence of right-sided lesions.     

Unprocessed Bran in Treatment of Diverticular Disease of the Colon

Seventy patients with diverticular disease of the colon were treated with a high-residue, low-sugar diet including unprocessed bran. Follow-up for an average of 22 months showed marked relief of symptoms in 62 patients. Bowel habit was restored towards normal and abdominal discomfort relieved. Only seven patients were unable to give up the use of laxatives. Eight patients did not tolerate the bran diet, and one of these needed surgical treatment. None of the 62 patients who took the diet needed surgery.     

Computer-aided Diagnosis of Acute Abdominal Pain

This paper reports a controlled prospective unselected real-time comparison of human and computer-aided diagnosis in a series of 304 patients suffering from abdominal pain of acute onset.The computing system''s overall diagnostic accuracy (91·8%) was significantly higher than that of the most senior member of the clinical team to see each case (79·6%). It is suggested as a result of these studies that the provision of such a system to aid the clinician is both feasible in a real-time clinical setting, and likely to be of practical value, albeit in a small percentage of cases.     

The Dipole Model and Phase Transitions in Biological Membranes

Assuming the dipole model for a membrane, approximate calculations are made which employ a dipole-dipole interaction energy. The calculations are based upon the assumption of cooperative coupling of membrane polar molecules and make use of the Bragg-Williams approximation. A theoretical estimate is made of the critical temperature at which phase changes might occur in certain biological membranes. Proposals are presented which explain how the dipole transition might relate to the sometimes observed thermal phase transitions in biological membranes.