Identification of accessory bile ducts at cholecystectomy

The presence of accessory channels between the liver and extrahepatic bile ducts has long been recognised by anatomists and the division of such ducts may be a cause of bile leakage following cholecystectomy. However, visualisation of accessory bile ducts at operation is difficult as they are often small and sometimes less than 1 mm in diameter. Cholangiography has been used to help in the identification of accessory ducts in 50 patients included in a prospective trial. X-rays were taken after dissection of the gall bladder from its bed and extravasation of contrast was seen on five occasions (10%) suggesting leakage from divided accessory ducts. The identification of damage to accessory bile ducts in 10% of patients suggests that this may occur more frequently than previously supposed.     

Preparation of protected peptidyl thioester intermediates for native chemical ligation by Nα‐9‐fluorenylmethoxycarbonyl (Fmoc) chemistry: considerations of side‐chain and backbone anchoring strategies,and compatible protection for N‐terminal cysteine*,†

Abstract: Native chemical ligation has proven to be a powerful method for the synthesis of small proteins and the semisynthesis of larger ones. The essential synthetic intermediates, which are C‐terminal peptide thioesters, cannot survive the repetitive piperidine deprotection steps of N^α‐9‐fluorenylmethoxycarbonyl (Fmoc) chemistry. Therefore, peptide scientists who prefer to not use N^α‐t‐butyloxycarbonyl (Boc) chemistry need to adopt more esoteric strategies and tactics in order to integrate ligation approaches with Fmoc chemistry. In the present work, side‐chain and backbone anchoring strategies have been used to prepare the required suitably (partially) protected and/or activated peptide intermediates spanning the length of bovine pancreatic trypsin inhibitor (BPTI). Three separate strategies for managing the critical N‐terminal cysteine residue have been developed: (i) incorporation of N^α‐9‐fluorenylmethoxycarbonyl‐S‐(N‐methyl‐N‐phenylcarbamoyl)sulfenylcysteine [Fmoc‐Cys(Snm)‐OH], allowing creation of an otherwise fully protected resin‐bound intermediate with N‐terminal free Cys; (ii) incorporation of N^α‐9‐fluorenylmethoxycarbonyl‐S‐triphenylmethylcysteine [Fmoc‐Cys(Trt)‐OH], generating a stable Fmoc‐Cys(H)‐peptide upon acidolytic cleavage; and (iii) incorporation of N^α‐t‐butyloxycarbonyl‐S‐fluorenylmethylcysteine [Boc‐Cys(Fm)‐OH], generating a stable H‐Cys(Fm)‐peptide upon cleavage. In separate stages of these strategies, thioesters are established at the C‐termini by selective deprotection and coupling steps carried out while peptides remain bound to the supports. Pilot native chemical ligations were pursued directly on‐resin, as well as in solution after cleavage/purification.     

Sex steroid effects on extrahypothalamic CNS. II. Progesterone, alone and in combination with estrogen, modulates cerebellar responses to amino acid neurotransmitters

In a preliminary report we have shown that both intravenous and local application of progesterone (P) are capable of increasing cerebellar Purkinje cell responsiveness to microiontophoretically applied gamma-aminobutyric acid (GABA) and decreasing responsiveness to glutamate (GLUT) in the urethane-anesthetized, ovariectomized adult rat. In the present study we have examined the time course of effects of several doses of P and different combinations of both E2 and P on responses of individual Purkinje cells to GABA and GLUT. Extracellular activity of single Purkinje neurons was recorded using multibarrel glass micropipets. Spontaneous firing rate and responses of neurons to microiontophoretic pulses (10 s pulses every 40 s) of GABA (10-50 nA) and GLUT (3-40 nA) were examined before and after jugular i.v. administration of P or E2/P combinations to ovariectomized rats. In some cases animals received s.c. injections of E2 (2 micrograms) at 24 and 48 h before the day of recording. This injection schedule results in maximal reproductive effects of P. Within 5-15 min after P administration (5,50 or 500 micrograms) to ovariectomized rats, Purkinje cell responses to GLUT were decreased by 87%, and inhibitory responses to GABA were increased by 50%, with no associated change in spontaneous firing rate. In addition, the magnitude of the change in amino acid response was directly proportional to the dose of P. In most cases, complete recovery was observed 20-45 min after P administration. E2 pretreatment did not alter these P-induced effects. Combinations of E2 (300 ng/kg) and P (50 or 500 micrograms) injected simultaneously resulted in effects on GLUT responsiveness which were similar to those seen with P alone, while effects similar to E2 alone were observed with administration of E2 plus P at 5 micrograms. The administration of a protein synthesis inhibitor, anisomycin (30 mg/kg, i.v.), 20 min before the recording session did not prevent any of the above steroid effects. These results indicate that sex steroids can act to alter neuronal responsiveness to putative neurotransmitters in a CNS region not known to contain steroid receptors and that the particular combination of steroids will determine the neuronal response. These findings further suggest that the observed steroid-induced alterations in Purkinje cell responsiveness do not appear to require genomic mechanisms.     

Direct evidence that primary acquired cell-mediated immunity is less resistant than is primary thymus-dependent humoral immunity to the depressive influence of wasting protein-energy malnutrition in weanling mice.

Wasting protein-energy malnutrition (PEM) was induced in male C57BL/6J mice fed a low-protein diet ad libitum from 23 to 37 d of age. In comparison with a complete diet, the low-protein formulation reduced delayed hypersensitivity to sheep red blood cells (SRBCs) assessed on day 14 of feeding by measuring increased footpad thickness (mean +/- SD: 4 +/- 4% vs 22 +/- 8%, P less than 0.01), after immunization on day 9, and after challenge with SRBCs on day 13. By contrast, the low-protein diet did not affect the anti-SRBC hemagglutinin titer (8.3 +/- 2.2 vs 9.1 +/- 1.1, P greater than 0.30) despite profound reduction in numbers of splenic plasma cells secreting IgM-class anti-SRBCs (7.3 +/- 3.1 vs 49.9 +/- 23.8 x 10(-3), P less than 0.001), after immunization on day 9 and assessment on day 14. Thus, direct experimental evidence, previously altogether lacking, is provided in support of the concept, central to nutritional immunology, that acquired cell-mediated immunity is less resistant than is systemic humoral immunity to the depressive influence of pre-adolescent, wasting PEM.