Conformational analysis of possible biologically active (receptor-bound) conformations of peptides derived from cholecystokinin, cerulein and little gastrin and the opiate peptide, Met-enkephalin

Possible biologically active (receptor-bound) conformations of peptides derived from cholecystokinin (CCK) have been deduced using conformational analysis combined with comparative studies of their biological specificities. Two peptides, the completely active carboxyl terminal heptapeptide from CCK (CCK-7), whose sequence is Tyr-Met-Gly-Trp-Met-Asp-Phe-NH2, and the carboxyl terminal heptapeptide from cerulein (CER-7) which has the same sequence as for CCK-7 except for replacement of Met 2 with a Thr 2, both stimulate peripheral receptors in gall bladder, pancreas, and pylorus in the gastrointestinal system. In contrast, two other very similar peptides, the last four residues of CCK (CCK-4) whose sequence is Trp-Met-Asp-Phe-NH2, and the carboxyl terminal hexapeptide of little gastrin (LGA-6, Tyr-Gly-Trp-Met-Asp-Phe-NH2, i.e., residue 2 deleted relative to CCK-7 and CER-7 sequences), interact specifically with gastrin receptors and not at all or very weakly with peripheral receptors. All of these peptides react with CCK receptors in the central nervous system, especially in forebrain. The results in the GI tract suggest that the peptides active on peripheral receptors adopt structures that are significantly different from those of the peptides that interact with gastrin receptors. We have generated all of the many low energy conformations for each of these peptides. By retaining only the conformations that are the same for peptides within the same group and then rejecting those resulting conformations that are the same for the peptides in the two different groups, we can greatly reduce the possible active conformations for the peptides within each class.(ABSTRACT TRUNCATED AT 250 WORDS)

Biliary cystadenocarcinoma of extrahepatic duct origin arising in previously benign cystadenoma

A case of biliary cystadenocarcinoma arising from the common hepatic duct in a 47-yr-old woman who had two previous attempts at cure by local excision of a then-benign biliary cystadenoma is reported, adding further evidence that resection is the preferred treatment of these tumors, even when histologically benign. A review of the literature and of pertinent clinical and pathological features of the 32 previously reported cases is included.

On the biologically active structures of cholecystokinin, little gastrin, and enkephalin in the gastrointestinal system

The biologically active conformations of a series of four peptides [four cholecystokinin (CCK)-related peptides and enkephalin] in their interactions with gastrointestinal receptors have been deduced using conformational computational analysis. The two peptides that interact exclusively with peripheral-type CCK receptors are the heptapeptide COOH-terminal fragment from CCK (CCK-7) and the analogous sequence from cerulein (CER-7) in which threonine replaces the methionine proximal to the NH2 terminus. The two peptides that interact exclusively with the gastrin receptor in the stomach are the active COOH-terminal fragment of little gastrin and the COOH-terminal tetrapeptide sequence common to all of these peptides, CCK-4. We find that preferred conformations for the peripherally active peptides CCK-7 and CER-7 are principally beta-bends, whereas little gastrin and CCK-4 are fundamentally helical. In the class of lowest energy structures for both CCK-7 and CER-7, the aromatic rings of the tyrosine and phenylalanine lie close to one another whereas the tryptophan indole ring points in the opposite direction. This structure is superimposable on the structures of a set of rigid indolyl benzodiazepine derivatives that interact with complete specificity and high affinity with peripheral CCK receptors further suggesting that the computed beta-bends are the biologically active conformation. The biologically active conformation for CCK-4 and the little gastrin hexapeptide has also been deduced. By excluding conformations common to CCK-7 and CCK-4, which do not bond to each other's receptors, and then by selecting conformations in common to CCK-4 and the gastrin-related hexapeptide, which do bind to each other's receptors, we deduce that the biologically active conformation at the gastrin receptor is partly helical and one in which the indole of tryptophan and the aromatic ring of phenylalanine are close to one another while the methionine and aspartic acid side chains point in the opposite direction. These major differences in preferred structures between the common CCK-7/CER-7 peptides and the common CCK-4/little gastrin peptides explain the mutually exclusive activities of these two sets of peptides. We have observed that [Met]enkephalin strongly antagonizes the action of the naturally occurring peripherally active CCK-8 (CCK-7 with an NH2-terminal aspartic acid residue added). The computed lowest energy structures for this opiate peptide closely resemble key features of the computed CCK-7/CER-7 structure, further supporting the proposed structure.

High sensitivity assay for the alpha 2 antagonist 6-chloro-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine and its desmethyl metabolite in plasma using gas chromatography mass spectrometry with ammonia/CCl4 chemical ionization

A rapid and highly sensitive assay for quantifying the alpha 2-adrenoceptor antagonist SK&F 86466 and a desmethyl metabolite has been developed, using capillary column gas chromatography/chemical ionization mass spectrometry. This assay uses deuterium-labeled analogs of the analytes as internal standards, and has a lower limit of quantification of 100 pg ml-1. A novel reagent gas, consisting of carbon tetrachloride in anhydrous ammonia, was used to achieve maximal sensitivity.

The duration of lochia

The duration of lochia and its association with a number of obstetric variables was studied in 236 women. Each woman completed a diary sheet describing the colour and duration of her lochia for up to 60 days post partum. The phases of lochia were divided according to the classical description; lochia rubra, serosa and alba. The median total duration of lochia was 33 days, lochia rubra 4 days and lochia serosa 22 days. Lochia persisted to 60 days in 13% of women. The duration of lochia was shorter in parous women and women with smaller babies.

Phlegm production and lung function among cigarette smokers changing tar groups during the 1970s

In 1971-3 data on smoking habits, cigarette brand smoked, morning phlegm production, and lung function were recorded for factory workers as part of the Heart Disease Prevention Project. These men were reassessed in 1984 and those who had always smoked cigarettes from the same tar group were compared with those who had dropped one tar group (mean decreases of 6.6 mg tar, 0.1 mg nicotine) and two tar groups (mean decreases of 11.9 mg tar, 0.5 mg nicotine). Over the 13 years, men who had dropped one tar group were significantly more likely (p less than 0.05) to stop producing phlegm, but the effect was less marked for those who had dropped two tar groups. The mean fall in FEV1 was similar in all three groups, but 95% confidence limits showed that although dropping one tar group could be associated with at most a saving of 84 ml over the follow up period, there could be little extra benefit from dropping two tar groups. In 1984, all three groups of smokers excreted similar amounts of nicotine metabolites in the urine, suggesting that men who had dropped two tar groups compensated for the reduced nicotine yield of their cigarettes. This could account for the lack of a dose response relationship between reduction in the tar yield of cigarettes and cessation of phlegm and fall in FEV1.

Validity of smokers' information about present and past cigarette brands--implications for studies of the effects of falling tar yields of cigarettes on health

Four hundred and twenty nine current smokers and ex-smokers who had provided details 12 years previously completed a self administered questionnaire about their present and past smoking habits, and two weeks later current smokers supplied an empty cigarette packet. The tar group and brand name of the current cigarette given on the questionnaire were compared with details on the packet, and the brand alleged to have been smoked 12 years ago was compared with that actually recorded at that time. Only 55% of "low middle" tar cigarettes as indicated by returned packets had been correctly identified in the questionnaire. The brand name was the same in the questionnaire and on the packet in 74% of cases. The recalled brand was confirmed by past records in only 49% of cases. It is concluded that current smokers should be asked to return an empty packet or packets of the cigarette brand or brands usually smoked with a self administered questionnaire and that follow up studies of populations for which brands of cigarette smoked were previously recorded might be more valid than studies relying on recall.

A double-blind randomized controlled trial of the effect of a low- versus a middle-tar cigarette on respiratory symptoms--a feasibility study

A feasibility study of a double-blind, randomized controlled trial of the effect of a low-versus a middle-tar cigarette on respiratory symptoms is described. A smoking questionnaire was sent to 19,366 households. Returned questionnaires (64%) yielded 604 middle-tar cigarette smokers aged 20-44 years; 342 replied to a health warning stating that they did not want to or had failed to stop smoking and of these 183 volunteered for the trial. Thus about every 100 households originally mailed yielded one volunteer. Of the volunteers, 95 men were randomly allocated to be sold a middle-tar cigarette and 88 to be sold a low-tar cigarette of identical appearance. The cigarettes were sold at three different reduced prices and the men were asked to smoke them for five weeks. There was a 22% drop-out and this was unrelated to type of cigarette smoked. A reduction in price of 20% was sufficient incentive for volunteers to participate. Cigarette butts were collected weekly or fortnightly and urine samples were collected initially and after three and five weeks. Compliance with the trial cigarettes was good. The excretion of nicotine metabolites, number of cigarettes smoked and average butt weight for men allocated the low-tar cigarette was not significantly different from that of those allocated the middle-tar cigarette. This suggested that the former compensated for the 37% reduction in the nicotine yield of their cigarette by taking more frequent or deeper puffs from their cigarette. The implications of these results for a large-scale, randomized controlled trial are discussed.

The effect of serotonergic blockade in postpartum preeclamptic patients

Thirty postpartum preeclamptic patients from the University of South Florida Obstetrical Service were enrolled in a placebo-controlled, randomized, double-blind study to test the effectiveness of ketanserin in lowering the blood pressure. An intravenous bolus of ketanserin resulted in a significant drop in the mean arterial blood pressure. The decrease in the blood pressure could be maintained by a continuous infusion of ketanserin. Hypertension returned after the medication was discontinued. These observations suggest that ketanserin, a selective blocker of type II serotonin receptors, may be effective in acutely reducing elevated postpartum blood pressure in preeclamptic patients, and that serotonin may play a role in the pathogenesis of preeclampsia, but not be important as a mediator in the severity of the disease.

Generalised epileptic fits in renal transplant recipients given cyclosporin A

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Epithelial patchy necrosis in Crohn's disease

Electron and light microscopic studies of the intestinal epithelium in Crohn's disease demonstrated localized areas of damage to the superficial epithelium, occurring without accompanying acute inflammation. In a blind study of rectal biopsy specimens from seven patients with Crohn's disease, four with ulcerative colitis, and four normal controls, this finding of patchy necrosis without acute inflammation was observed exclusively in four of the seven cases of Crohn's disease.

Evidence of diffusion artefacts in diaminobenzidine immunocytochemistry revealed during immune electron microscope studies of the early interactions between influenza virus and cells

Anti-haemagglutinin-labelled antibodies have been used to search for influenza entry into cells by fusion of viral and plasma membranes. The plasma membranes of infected cells were stained by immunoperoxidase but not by immunoferritin reagents. It is suggested that the staining obtained with the peroxidase conjugate was due to diffusion of the diaminobenzidine reaction product away from the enzymic site. Immunoferritin labelling provided no evidence for entry of influenza by fusion of viral and plasma membranes under conditions of physiological pH.

High Performance Liquid Chromatographic Determination of Intermediates and Reaction By-Products in FD&C Yellow No. 5: Collaborative Study

Eight laboratories participated in a collaborative study of an ion exchange high performance liquid chromatographic procedure for determining the intermediates and 2 reaction by-products in FD&C Yellow No. 5: phenylhydrazine-p-sulfonic acid (PHSA), sulfanilic acid (SA), l-(4-sulfophenyl)-3- carboxy-5-hydroxypyrazolone (PyT), l-(4-sulfophenyl) - 3 -ethylcarboxy-5-hydroxypyrazolone (EEpyT), and 4,4'-(diazoamino)-dibenzenesulfonic acid (DAADBSA). The repeatability and reproducibility standard deviations (absolute) found in the study were 0.0134 and 0.0263 for PHSA at the 0.1% level, 0.0246 and 0.0256 for SA at the 0.2% level, 0.0124 and 0.0149 for EEpyT at the 0.1% level, 0.0212 and 0.0258 for PyT at the 0.2% level, and 0.0234 and 0.0373 for DAADBSA at the 0.2% level. The method was adopted official first action.

Glaucoma in a case of Hurler disease

The electron microscopic appearances of the corneoscleral and iris tissue removed at operation from a child with Hurler disease and glaucoma showed distinctive swollen cells with intracellular inclusions similar to those which are observed in other tissues in these patients and which are due to abnormal lysosomal storages of mucopolysaccharides. Some recent observations on the possible relationship between mucopolysaccharides and the drainage of fluid from the anterior chamber are briefly reviewed and correlated with the present observations. The development of glaucoma in this patient is thought to be associated with the presence of the mucopolysaccharide-containing cells in the region of the aqueous drainage channels.

Pathologic interactions between prosthetic aortic grafts and the gastrointestinal tract. Clinical problems and a new experimental approach

Twenty-one patients presented with pathologic interactions between the gastrointestinal tract and aortic grafts. Seventeen patients were managed by excision of the graft and axillobifemoral bypass. Six patients died. four deaths were due to disruption of the proximal aortic stump after initial therapy that appeared successful. An experimental model of a seromuscular jejunal patch is presented that may be beneficial for closure of the proximal aortic stump.

Nonresective treatment of abdominal aortic aneurysms. Use of acute thrombosis and axillofemoral bypass

In good-risk patients, abdominal aortic aneurysmectomy can be accomplished with a mortality of 2% to 5%. However, in poor-risk patients, ie, those with severe reduction of cardiac, respiratory, and/or renal function, the mortality of this procedure has been reported to be as high as 60%. Fifteen poor-risk patients with abdominal aortic aneurysms have been treated with acute, induced thrombosis and simultaneous axillobilateral femoral bypass. Each patient had preoperative ultrasound and radionucleide flow studies and the runoff from the aneurysm was determined angiographically. Thrombosis, induced by interruption of the iliac outflow vessels, occurred in 12 patients within 72 hours. Flow persisted in three patients, and thrombosis was induced by transaxillary catheter deposition of bucrylate in the residual outflow vessels. There were two operative deaths (less than 30 days), both due to myocardial infarctions, and four late deaths, three of which were caused by the problems that initially contraindicated direct graft replacement of the aneurysm. Preliminary experience with this approach indicates that this is a simple and potentially effective method of treatment of abdominal aortic aneurysm where direct graft replacement is contraindicated.

Partial regeneration of the above-elbow amputated rat forelimb. II. Electrical and mechanical facilitation

This investigation was undertaken to examine the observations of Becker ('72) pertaining to the electrical facilitation of partial limb regenerative responses by means of Ag-Pt wire couples applied to the limb stumps of young, forelimb-amputated white rats. Additionally, in order to examine the possible role of mechanical effects of such device implantations, we have employed uncoupled devices delivering no current or potential difference. In the present experiments, in response to coupled device implantation, cartilage and bone were actively formed in the vicinity of the Pt electrode tip. These tissues contributed to the lengthwise extension of the limb and to the partial restoration of the distal humeral extremity. In limbs bearing the uncoupled electrical devices, qualitatively similar responses were noted, but osteogenesis was diminished in extent compared to that seen in limbs bearing the active or coupled devices. It is therefore necessary to consider the role of mechanical factors in the elicitation of the observed regenerative responses. Myogenesis was enhanced in electrically stimulated limbs, but not in those rats bearing uncoupled devices.

Partial regeneration of the above-elbow amputated rat forelimb. I. Innate responses

Although a number of recent studies describe the facilitation of limb regeneration by electrical and other forms of stimulation, little is known of innate regenerative capacity in the mammalian limb. The present report describes spontaneous regenerative responses following subtotal forelimb amputation in the young white rat. In one group of animals the forelimb was amputated through the lower humerus and the skin sutured closed. In a second group, adjacent muscle tissue still attached to bone at its origin(s) was interposed between the cut surface of the humerus and the skin. Among animals of the first group (skin closure only) bone growth and limb regenerative responses were generally not observed. Animals of the second group displayed significant elaborations of cartilage and bone at the limb terminus. The appearance and subsequent modification of these tissues suggest that some capacity for limb regeneration exists innately in the young rat and can be more readily evoked than has been recognized heretofore. It is concluded that extant and forthcoming reports of electrically stimulated skeletal tissue growth, repair and regeneration among eutherial mammals should be examined to determine whether reported responses to stimulation represent advances beyond what might be expected from innate replacement processes alone.

Hypertonic mannitol in the therapy of the acute respiratory distress syndrome

Increased pulmonary artery pressure, an increase in pulmonary vascular resistance and an increase in physiologic dead space are consistent findings in patients with post-traumatic respiratory distress. Since mannitol has been shown to decrease renal vascular resistance following trauma, the effect of a bolus injection of 100 ml of 25% solution of this drug on pulmonary hemodynamics and physiologic dead space was investigated in 11 patients who had suffered multiple trauma. Five minutes after the injection, pulmonary vascular resistance fell (p less than .01), cardiac index increased (p less than .001) and physiologic dead space decreased (p less than .05). In contrast, the administration of 40 mg of furosemide produced no significant change in any of these parameters. Mannitol rapidly equilibrates in the extracellular space and exerts an osmotic effect across cell membranes. We postulate that the beneficial response to mannitol on the pulmonary vascular resistance and the improved perfusion of ventilated regions of the lung is due to a reduction in cell swelling and is not explainable by its diuretic effect. Improvement in the distribution of perfusion of pulmonary blood flow by mannitol may be a useful aid in the treatment of the post-traumatic form of the respiratory distress syndrome.

Unusual case of laryngeal foreign body

The foreign bodies in respiratory tract have been major cause of morbidity and present as challenge to otolaryngologist. The spectrum of presentation varies widely from sudden death due to respiratory obstruction to accidental finding during routine investigation. One case of unusual presentation of laryngeal foreign body with loss of voice is described here. Key words: Respiratory obstruction laryngeal; foreign body DOI: 10.3126/jcmsn.v6i1.3601 Journal of College of Medical Sciences-Nepal, 2010, Vol. 6, No. 1, 44-46

Achondroplasia: Case Report and Review of Literature

A two month old male child presented to emergency of B. P. Koirala Institute of Health Sciences (BPKIHS), Dharan and was admitted to Paediatric ward with history of fever, cough and respiratory distress. On examination the breathing was rapid and shallow. The child was small for age with an upper to lower segment ratio of 1.9. The anteroposterior diameter of thorax was reduced. We report a very rare case of achondroplasia which was recognized in a two month age child who presented with severe pneumonia. Usually the clinically features of achondroplasia is more prominent when the child is growing in height but we diagnosed it in a two months child after performing the skeletal survey.   DOI: http://dx.doi.org/10.3126/jnps.v31i3.5363 J Nep Paedtr Soc 2011;31(3): 216-224-226