The physiological roles of dietary fibre

The term dietary fibre (indigestible carbohydrates of plant origin) encompasses a range of divergent compounds that differentially affect numerous important gastrointestinal and systemic bodily processes.     

The application of an ether cleavage technique to a study of the biodegradation of a linear alcohol ethoxylate nonionic surfactant

The biodegradation of a linear alcohol ethoxylate nonionic surfactant (C₁₂-C₁₅, eo₉) was studied by gas chromatography of the alkyl bromides produced by acid cleavage of the surfactant ether linkages with hydrogen bromide. In laboratory cultures and in a lake environment, a conventional method showed rapid loss of surface activity. The gas chromatographic method revealed a rapid degradation of the surfactant alkyl moiety but a slow and incomplete removal of the polyethoxylate moiety.     

Sequence analysis of the rat Brca1 homolog and its promoter region

OBJECTIVE: Isolated malleus-handle fracture is a clinical entity seldom reported in the medical literature but well known in the last century. The purpose of this paper was to review the literature over the last 150 years and describe three new cases. STUDY DESIGN: Extensive review of the literature and chart review of three patients with isolated malleus-handle fracture. SETTING: The study was performed partly at a private practice and partly in an academic tertiary referral center. PATIENTS: At least 43 malleus-handle fractures have been reported in the literature. Three new occurrences were studied. RESULTS: The review of the literature showed that head trauma with skull base fracture was the most frequent cause of malleus-handle fracture, followed by blows on the tympanic membrane and barotrauma, penetration of pen-holders or hair pins, penetration of twigs, and attempts to remove a foreign body pushed inside the ear. In the first patient reported here, the malleus-handle fracture was caused by a whirlpool bath, in the second, the cause was unknown, and, in the third, it was caused by a brisk decompression inside the ear canal. CONCLUSIONS: This lesion is not rare, and the diagnosis frequently is missed because the tympanic membrane appears intact. A careful otoscopic examination with pneumomassage, an abnormally high compliance at tympanometry, and a carefully recorded medical history may lead to the diagnosis of isolated malleus-handle fracture in a patient with a mild conductive hearing loss.     

Spontaneous thrombosis of an unruptured anterior communicating artery aneurysm. An unusual cause of ischemic stroke

BACKGROUND: Stroke caused by spontaneous thrombosis of an unruptured intracranial aneurysm is a rare event. CASE DESCRIPTION: A 66-year-old woman experienced a transient ischemic attack and cerebral infarctions due to spontaneous thrombosis of an unruptured anterior communicating artery aneurysm. Extension of thrombus into both anterior cerebral arteries and the left middle cerebral artery, resulting in ischemic infarction in all three vascular territories, was diagnosed by CT scanning, MRI, and cerebral angiography and confirmed at autopsy. CONCLUSIONS: This case illustrates a rare complication of an unruptured saccular aneurysm with neuroimaging and pathological correlation. Morphological and hemodynamic factors that may have precipitated aneurysm thrombosis are discussed with reference to experimental models.     

Immunocytochemical demonstration of neuropeptides in the peripheral nervous system of the roundworm Ascaris suum (Nematoda, Ascaroidea)

The localisation and distribution of neuropeptides in the peripheral nervous system of the pig roundworm Ascaris suum have been determined by an indirect immunofluorescence technique in conjunction with confocal microscopy. Of the 31 antisera tested, immunostaining was obtained only with antisera to peptide YY (PYY), pancreatic polypeptide (PP) and FMRFamide. Immunostaining for PYY and FMRFamide was evident in the amphidial and papillary ganglia associated with the anterior nerve ring and in the nerves from these ganglia that terminated in sensory receptors within the buccal lips of the parasite. The only peptide immunoreactivity (IR) observed in the reproductive system of either sex was that evident in the nerve supply to the distal region of the vagina in the female worm. It took the form of a well-developed plexus of parallel nerve fibres, cross-connectives and looped commissures. The nerve net diminished in the more proximal region of the vagina. PP-IR was less intense than that for PYY and FMRFamide and was more restricted in distribution, being confined to a small number of nerve fibres in the nerve supply to the vagina; it did not occur in the nerves supplying the anterior sensory receptors. The possible roles of neuropeptides in the sensory and reproductive biology of nematodes are discussed.     

The use of synthetic oligodeoxynucleotide primers in cloning and sequencing segment of 8 influenza virus (A/PR/8/34)

Complete double-stranded DNA copies of the RNA genes of the human influenza virus A/PR/8/34 have been synthesized by using two synthetic oligodeoxynucleotide primers. The gene encoding the non-structural proteins NS1 and NS2, prepared with these primers, has been cloned into the bacteriophage M13mp7 and sequenced. The sequence is compared with that from another human strain and from an avian strain.     

Ligand requirements for Ca2+ binding to EGF-like domains

Site-specific mutagenesis studies of the first epidermal growthfactor-like (EGF-like) domain of human clotting factor IX suggestthat the calcium-binding site present in this domain (dissociationconstant K_d=1.8 mM at pH 7.5 and ionic strength I=0.15) involvedthe carboxylate residues Asp47, Asp49 and Asp64. To furthercharacterize the ligands required for calcium binding to EGF-likedomains, two new mutations, Asp47 - Asn and Asp49 - Asn, wereintroduced into the domain by peptide synthesis. ¹H-NMR spectroscopywas used to obtain the dissociation constants for calcium bindingto these mutations. Calcium binding to the Asp49- Asn modifieddomain is only mildly affected (K_d=6 mM, I=0.15), whereas bindingto the Asp47- Asn modified domain is severely reduced (K_d=42mM, I=0.15). From these data, it is proposed that the anionicoxygen atoms of the side chains of residues 47 and 64 are essentialfor calcium binding, whereas the side chain ligand for calciumat residue 49 can be a carboxyamide oxygen. As a control, theintroduction of the modification Glu78- Asp in a region of thedomain not believed to be involved in calcium binding had verylittle effect on the K_d for calcium (K_d=2.6 mM, I=0.15). Finally,the effect of an Asp47- Gly substitution found in the naturalhaemophilia B mutant, factor IX_Alabama, was investigated. Thispeptide has a markedly reduced affinity for calcium (K_d=37 mM,I=0.15), suggesting that the defect in factor IX_Alabama is dueto impaired calcium binding to its first EGF-like domain.