PubMed Health⌕ Search

Biomedical subjects

K Go

Publications and source records attributed to K Go.

At least 19 recordsLinked to original sources
PubMed2004

Capsule endoscopy: a single-centre experience with the first 226 capsules.

BACKGROUND: Capsule endoscopy (CE) refers to a novel diagnostic method of imaging the gastrointestinal tract using a wireless capsule that transmits images to a data recorder while the device traverses the small intestine. OBJECTIVE: To review the authors' experience with CE to determine the indications, outcomes and management of positive findings. METHODS: Patients were prepared for CE with a single dose of magnesium citrate. Following an 8 h fast, a sensor array system was applied to the abdomen, the capsule was swallowed and the images were transmitted to a data recorder worn on the patient's side. Typically, the battery life of the capsule is 8 h, following which the data recorder is returned, downloaded to a computer workstation and reviewed. RESULTS: To date, 226 capsule studies have been performed in 209 patients. The indications included obscure bleeding (167 studies: 88 overt, 79 occult), anemia (14 studies), evaluation for inflammatory bowel disease (12 studies), screening for polyps (10 studies), pain (19 studies) and abnormal radiological imaging (4 studies). In the setting of obscure bleeding, a definitive source of bleeding was discovered in 85 studies. This included angiodysplasia (52 studies), mitotic lesions (10 studies) and ulcers (23 studies). A probable source of bleeding was found in another 10 capsule studies. In the setting of anemia without evidence of bleeding, the definitive findings included ulcers (three studies), angiodysplasia (two studies), mitotic lesions (one study) and celiac disease (one study). Of four patients with abnormal radiological imaging, CE demonstrated lesions in two. The results of 35 capsule studies led to laparotomy with curative surgical resection. In eight studies, the capsules became lodged within a stricture; none led to obstruction and three were managed endoscopically. CONCLUSION: The yield of CE in carefully selected patients with obscure bleeding approximates 51%. There appear to be few complications, and patient satisfaction appears high. Cost analysis and further studies of clinical outcomes are required to elucidate appropriate indications for this device.

Angiodysplasia↗
PubMed2001

Hypothermia induces T-cell production of immunosuppressive cytokines.

BACKGROUND: Hypothermia is associated with increased postoperative infectious complications. We hypothesized that hypothermia suppresses the inflammatory response by altering T-cell cytokine production from a proinflammatory to an antiinflammatory profile, thus explaining the increased susceptibility to infectious complications associated with perioperative hypothermia. METHODS: Forty rats were randomized to either a Hypothermia (30 degrees C) or Control (38 degrees C) group. Blood samples taken at baseline and after 8 h of thermoregulation were stimulated with phorbol 12-myristate 13-acetate and ionomycin. Interleukin (IL)-2 receptor expression and intracellular IL-10 production were measured using monoclonal antibodies and flow cytometry in CD4 and CD8 T cells. Differences in IL-10 production and IL-2 receptor expression for stimulated samples in the Hypothermia and Control groups were compared. RESULTS: Stimulated CD4 cells demonstrated an antiinflammatory cytokine expression profile after hypothermia. Intracellular IL-10 production increased in the Hypothermia group but remained the same in the Control group (% change = 40 [3,87] and 2 [-36,26], respectively; P = 0.043). The increase in IL-2 receptor expression observed in the control group was suppressed after hypothermia (% change = 12[8,30] and 1 [-3,13], respectively; P = 0.026). We observed a greater increase in IL-10 production by CD8 cells from hypothermic animals than in those from control animals (% change = 41 [-8,90] and -4 [-40,5], respectively; P = 0.019). CD8 IL-2 receptor expression in hypothermic animals was similar to that of control animals (% change = 23 [-7,37] vs 25 [2,80], respectively; P = 0.32). CONCLUSIONS: Hypothermia induced an antiinflammatory T-cell cytokine profile.

Animals↗
PubMed1998

Neurotropin induces antinociceptive effect by enhancing descending pain inhibitory systems involving 5-HT3 and noradrenergic alpha2 receptors in spinal dorsal horn.

Neurotropin, a non-protein extract from the inflamed skin of rabbits inoculated with vaccinia virus, has been clinically used as an analgesic drug in Japan. Its analgesic effect has been demonstrated by reduced mechano-nociception in hyperalgesic rats exposed to SART-stress (a repeated cold stress) for 5 days. In order to clarify the mechanism of the analgesic effect of neurotropin at the spinal cord level, we examined the effects of several neurotransmitter receptor antagonists given by intrathecal (i.t.) injection on the antinociceptive effect of intraperitoneally (i.p.) injected neurotropin [100 and 200 Neurotropin Unit (NU)/kg]. The analgesic effect of neurotropin was significantly inhibited not only by methysergide (100 nmol/rat, i.t.), a non-selective antagonist against serotonin (5-HT), but also MDL 72222 (30 nmol/rat, i.t.), a selective 5-HT3 antagonist, but not influenced by ketanserin (100 nmol/rat, i.t.), a 5-HT2A antagonist. The antinociceptive effect of neurotropin (200 NU/kg, i. p.) was significantly inhibited also by yohimbine (30 nmol/rat, i.t.), a noradrenergic alpha2 antagonist. However, the analgesic effect of neurotropin (100 and 200 NU/kg, i.p.) was not influenced by naloxone (30 nmol/rat, i.t.), an opioid antagonist. These results suggest that the mechanism of the antinociceptive effect of neurotropin is via enhancement of endogenous descending pain inhibitory pathways of the serotonergic and noradrenergic systems, especially involving 5-HT3 and noradrenergic alpha2 receptors in spinal dorsal horn in which these neurons terminate. No influence of opioid receptors at the spinal cord level is indicated.

Adrenergic Antagonists↗
PubMed1996

Role of diaphragmatic, visceral, and parietal pathways in peritoneal fluid absorption in rat peritoneal dialysis.

Assessment was made of the contribution of lymphatic and nonlymphatic fluid absorption to net fluid loss from the peritoneal cavity. Diaphragmatic, visceral, and parietal pathways in lymphatics and nonlymphatics were examined using a rat model with adhesion of the diaphragm to the liver, evisceration, these two procedures in combination, and without treatment. In each of these cases, six rats were used, each dialyzed for 180 min with Krebs-Ringer solution. The peritoneal net fluid absorption rate (PNFAR) was determined based on the disappearance of 125I-bovine serum albumin (BSA) from the peritoneal cavity and the lymphatic absorption rate (LAR), was based on the appearance of this albumin in the blood. Seventy-eight percent of net fluid loss occurred via the nonlymphatic pathway, primarily through parietal and visceral absorption; and the remaining 22% through the lymphatics, the main pathway being the subdiaphragmatic lymphatics. Nonlymphatic fluid absorption would thus appear to be a major route of fluid loss from the peritoneal cavity in rat peritoneal dialysis.

Absorption↗
PubMed1995

Crystal structure and a twisted beta-sheet conformation of the tripeptide L-leucyl-L-leucyl-L-leucine monohydrate trimethanol solvate: conformation analysis of tripeptides.

In order to test the helical preference of short oligo-L-leucines, we crystallized the tripeptide L-leucyl-L-leucyl-L-leucine (LLL) and carried out x-ray diffraction studies of it (L-leucyl-L-leucyl-Lleucine)2. 3CH3OH. H2O, (C39H84N6O12), crystallized in the monoclinic system, space group P2(1), cell parameters: a = 12.031(2), b = 15.578(3), c = 14.087(2) A, alpha = 90 degrees, beta = 97.29(1) degrees, gamma = 90 degrees, V = 2618.6 A3, MW = 829.1, Dc = 1.051 g cm-3, R index of 0.057 for 4213 reflections (lambda CuK alpha = 1.5418 A) > 2 sigma. LLL takes up the beta-sheet rather than a helical conformation in the crystalline state. The three methanol molecules and the water molecule that constitute the solvent of crystallization form a network of hydrogen bonds to the LLL molecules and to one another. It is rather remarkable that though A and L have stronger helical preferences than G, neither AAA nor LLL form the crystalline helix but GAL does, indicating that the helical preferences depend on the sequence context. The residue L2 in molecule A and the residues L1 and L3 of molecule B do not show the preferred conformation for forming helices. Further, very remarkably, LLL exhibits a unique supersecondary feature of the protein folding topology, namely the twisted beta-sheet, whereas most short peptides show only the classical beta-sheet conformation.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Helix-forming tendencies of amino acids depend on their sequence contexts: tripeptides AFG and FAG show incipient beta-bulge formation in their crystal structures.

Many of the theoretical methods used for predicting the occurrence of alpha-helices in peptides are based on the helical preferences of amino acid monomer residues. In order to check whether the helix-forming tendencies are based on helical preferences of monomers only or also on their sequence contexts, we synthesized permuted sequences of the tripeptides GAF, GAV, and GAL that formed crystalline helices with near alpha-helical conformation. The tripeptides AFG and FAG formed good crystals. The x-ray crystallographic studies of AFG and FAG showed that though they contain the same amino acids as GAF but in different sequences, they do not assume a helical conformation in the solid state. On the other hand, AFG and FAG, which contain the same amino acids but in a different sequence, exhibit nearly the same backbone torsion angles corresponding to an incipient formation of a beta-bulge, and exhibit nearly identical unit cells and crystal structures. Based on these results, it appears that the helix-forming tendencies of amino acids depend on the sequence context in which it occurs in a polypeptide. The synthetic peptides AFG (L-Ala-L-Phe-Gly) and FAG (L-Phe-L-Ala-Gly), C14H19N3O4, crystallize in the orthorhombic space group P2(1)2(1)2(1), with a = 5.232(1), b = 14.622(2), c = 19.157(3) A, Dx = 1.329 g cm-3, Z = 4, R = 0.041 for 549 reflections for AFG, and with a = 5.488(2), b = 14.189(1), c = 18.562(1) A, Dx = 1.348 g cm-3, Z = 4, R = 0.038 for 919 reflections for FAG. Unlike the other tripeptides GAF, GGV, GAL, and GAI, the crystals of AFG and FAG do not contain water molecule, and the molecules of AFG aor FAG do not show the helical conformation. The torsion angles at the backbone of the peptide are psi 1 = 144.5(5) degrees; phi 2, psi 2 = -98.1(6) degrees, -65.2(6) degrees; phi 3, psi 13, psi 31 = 154.1(6) degrees, -173.6(6) degrees, 6.9(8) degrees for AFG; and psi 1 = 162.6(3) degrees; phi 2, psi 2 = -96.7(4) degrees, -46.3(4) degrees; phi 3, psi 13, psi 31 = 150.1(3) degrees, -168.7(3) degrees, 12.2(5) degrees for FAG. The conformation angles (phi, psi) for residues 2 and 3 for both AFG and FAG show incipient formation of an beta-bulge.

Amino Acid Sequence↗
PubMed1993

Microsurgical aspiration of sperm from the epididymis: a mobile program.

We report data from 25 microsurgical aspirations of the epididymis on 22 men. There were 14 men with congenital absence of the vas, 6 with failed vasoepididymostomy, 1 with adult cystic fibrosis and 1 with a childhood hernia repair. The specimens were used for assisted reproductive technologies, including in vitro fertilization and tubal embryo transfer. The protocol for aspiration, ovulation induction and sperm processing evolved during the course of these studies, and the patients were classified into 2 groups on the basis of methodology. Seventeen procedures were performed for the in-house in vitro fertilization team but 8 other procedures were done for nearby in vitro fertilization centers, and the final prepared sperm samples were transported as part of our mobile program. Group 1 patients underwent standard aspiration techniques, standard ovulation induction and sperm processing by wash and swim up. Among this group there were no fertilizations or pregnancies with 8 in-house and 2 transported specimens. Group 2 patients had leuprolide suppression before ovulation induction, direct intratubular aspiration and a complex sperm preparation, including pentoxifylline stimulation, mini-Percoll filtration and incubation with human follicular fluid. Among this group there were 2 fertilizations and 1 pregnancy with 9 in-house cases, and 3 fertilizations and 2 pregnancies with 6 transported specimens. These results suggest that a mobile program for microsurgical aspirations of sperm from the epididymis and in vitro fertilization or tubal embryo transfer is feasible within the framework of a strict protocol.

Epididymis↗
PubMed1992

Helix-forming tendencies of amino acids depend on the restrictions of side-chain rotamer conformations: crystal structure of the tripeptide GAI in two crystalline forms.

In our attempts to design crystalline alpha-helical peptides, we synthesized and crystallized GAI (C11H21N3O4) in two crystal forms, GAI1 and GAI2. Form 1 (GAI1) Gly-L-Ala-L-Ile (C11H21N3O4.3H2O) crystals are monoclinic, space group P2(1) with a = 8.171(2), b = 6.072(4), c = 16.443(4) A, beta = 101.24(2) degrees, V = 800 A3, Dc = 1.300 g cm-3 and Z = 2, R = 0.081 for 482 reflections. Form 2 (GAI2) Gly-L-Ala-L-Ile (C11H21N3O4.1/2H2O) is triclinic, space group P1 with a = 5.830(1), b = 8.832(2), c = 15.008(2) A, alpha = 102.88(1), beta = 101.16(2), gamma = 70.72(2) degrees, V = 705 A3, Z = 2, Dc = 1.264 g cm-3, R = 0.04 for 2582 reflections. GAI1 is isomorphous with GAV and forms a helix, whereas GAI2 does not. In GAI1, the tripeptide molecule is held in a near helical conformation by a water molecule that bridges the NH3+ and COO- groups, and acts as the fourth residue needed to complete the turn by forming two hydrogen bonds. Two other water molecules form intermolecular hydrogen bonds in stabilizing the helical structure so that the end result is a column of molecules that looks like an incipient alpha-helix. GAI2 imitates a cyclic peptide and traps a water molecule. The conformation angles chi 11 and chi 12 for the side chain are (-63.7 degrees, 171.1 degrees) for the helical GAI1, and (-65.1 degrees, 58.6 degrees) and (-65.0 degrees, 58.9 degrees) for the two independent nonhelical molecules in GAI2; in GAI1, both the C gamma atoms point away from the helix, whereas in GAI2 the C gamma atom with the g+ conformation points inward to the helix and causes sterical interaction with atoms in the adjacent peptide plane. From these results, it is clear that the helix-forming tendencies of amino acids correlate with the restrictions of side-chain rotamer conformations. Both the peptide units in GAI1 are trans and show significant deviation from planarity [omega 1 = -168(1) degrees; omega 2 = -171(1) degrees] whereas both the peptide units in both the molecules A and B in GAI2 do not show significant deviation from planarity [omega 1 = 179.3(3) degrees; omega 2 = -179.3(3) degrees for molecule A and omega 1 = 179.5(3) degrees; omega 2 = -179.4(3) degrees for molecule B], indicating that the peptide planes in these incipient alpha-helical peptides are considerably bent.

Amino Acid Sequence↗
PubMed1992

Changes in muscarinic acetylcholine receptors in the isolated duodenum from repeatedly cold-stressed rats and the effect of neurotropin.

In rats repeatedly cold-stressed by specific alternation of rhythm in environmental temperature (SART-stressed rats), the contractile response to acetylcholine (ACh) of the isolated duodenum was remarkably decreased, whereas the contractile responses to K+, Ba2+ and Ca2+ were comparable to those in non-stressed rats. The amount of [3H]quinuclidinyl benzilate in the duodenum of SART-stressed rats was about 50% of that in non-stressed rats, but the KD value remained unchanged. Long-term administration of hexamethonium prevented the changes in SART-stressed rats. The daily treatment with Neurotropin, an extract isolated from inflamed rabbit dermis inoculated with vaccinia virus, dose-dependently prevented the changes in SART-stressed rats. However, Neurotropin had no effect on the ACh-induced decrease in muscarinic ACh receptor (m-ACh.R) in cultured vas deferens of guinea pig. These results suggest that down-regulation of m-ACh.R in duodenum by SART stress may be associated with enhanced activity in the parasympathetic center. Moreover, Neurotropin is thought to prevent the down-regulation of m-ACh.R throughout the central nervous system.

Acetylcholine↗
PubMed1992

Genetic offspring in patients with vaginal agenesis: specific medical and legal issues.

OBJECTIVE: There are new options for genetic offspring in patients with vaginal agenesis (Mayer-Rokitansky-Küster-Hauser syndrome). The reported world experience to date with genetic offspring of patients with vaginal agenesis consists of five pregnancies (including two reported here and two frozen embryos). The specifics of these cases are presented for discussion. STUDY DESIGN: We present a retrospective description of two women with vaginal agenesis and their matched gestational carriers with positive outcome of two live births. Care was delivered in a private in vitro fertilization and gamete intrafallopian transfer program. RESULTS: In vitro fertilization of oocytes gathered from the genetic mother with vaginal agenesis and sperm from the genetic father were transferred to a gestational carrier. Two live births and one blighted ovum pregnancy resulted. CONCLUSION: Until recently, treatment for patients with vaginal agenesis (Mayer-Rokitansky-Küster-Hauser syndrome) has centered on the creation of a functional vagina. The technology of in vitro fertilization and embryo transfer, allowing for collection of oocytes from the genetic mother, fertilization by the genetic father, and placement into a gestational carrier, enables a woman without a uterus to have her own genetic children. The specific medical and legal issues involved in facilitating genetic offspring in these instances must be considered; these include the initial matching of the genetic parents with the gestational carrier, cycle synchronization for in vitro fertilization and embryo transfer, anatomic difficulties of oocyte retrieval, birth certificate documentation, and the current legal status of a gestational carrier.

Adult↗
PubMed1992

Mechanism of nasal secretion mediated via nerve reflex in guinea pigs and evaluation of antiallergic drugs.

In order to confirm the mechanism of nasal secretion mediated via a nerve reflex in guinea pigs, the secretory response from the contralateral side was studied which was induced by local application of various stimulators. There was no difference in the nasal secretion between the contralateral and the stimulated sides when the secretion was induced by allergen, histamine, and capsaicin at lower doses. Methacholine caused a nasal secretion only on the stimulated side. Pretreatment with local anesthetic and ganglionic blockers blocked the secretory response bilaterally which was induced by allergen, histamine, and capsaicin. Antihistaminics also blocked the secretory response induced by allergen and histamine on both sides, but not the capsaicin-induced nasal secretion. Unilateral pretreatment with local anticholinergics prevented all secretory responses only on the stimulated side. Thus, exogenous and endogenous histamine released by the allergen-antibody reaction may stimulate histamine H1 receptors located in the sensory nerve endings as trigger, resulting in the secretory response mediated via a nerve reflex, while methacholine may act directly on nasal glands. Ketotifen and azelastine, which are chemical mediators releasing inhibitor with antihistaminergic activity, prevented the nasal secretion induced by histamine and allergen. On the other hand, disodium cromoglycate, amlexanox, and tranilast had only a slight effect on the allergen-induced nasal secretion. The secretory response on the contralateral side induced by various stimulators would be useful in the in vivo evaluation of anti-allergic drugs to demonstrate the difference in their modes of action.

Allergens↗
PubMed1992

Regulatory effect of neurotropin on nasal mucosal hypersensitivity in guinea pigs caused by SART (intermittent exposure to cold) stress.

We stated that SART-stressed guinea pigs showing nasal mucosal hypersensitivity would serve as an animal model for the in vivo evaluation of antiallergic drugs. In the present study, the mode of action of Neurotropin on nasal allergy compared with those of antiallergic drugs was studied by using SART-stressed guinea pigs. Daily administrations of Neurotropin improved the methacholine-induced hypersecretion and histamine-evoked sneeze response, which are parameters of nasal mucosal hypersensitivity, and increased the density of muscarinic ACh receptors located on the nasal mucosa caused by SART stress. In addition, the inhibitory action on nasal secretion in a passively sensitized model was more intense in SART-stressed guinea pigs than in normal ones. Ketotifen and tranilast were also found to have marked effects on nasal secretion in the passively sensitized SART-stressed model, but only had weak effects on nasal mucosal hypersensitivity. Neurotropin significantly potentiated the action of ketotifen or tranilast. Thus, at least part of the inhibitory effect of Neurotropin on nasal symptoms such as watery secretion and sneezing is thought to have been brought forth through the regulatory action on nasal mucosal hypersensitivity, and its combined use with antiallergic drugs would be a very effective therapeutic regimen for nasal allergy.

Analgesics↗
PubMed1992

Relationship between density of muscarinic receptors and nasal hypersecretion in a nasal allergic model.

In guinea pigs actively sensitized with ovalbumin, we have observed that nasal hyperreactivity and hypersensitivity to methacholine causes nasal secretion accompanied by an increase in the density of muscarinic acetylcholine receptor (m-ACh.R) following the appearance of nasal symptoms induced by the ovalbumin challenge. Therefore in the present investigation, we studied the relationship between the density of m-ACh.R and nasal hypersecretion in actively sensitized guinea pigs. There was no relationship between the quantity of nasal secretion and serum Ig G1 or Ig E levels. On the other hand, the sensitivity to methacholine and nasal secretion induced by methacholine were significantly related to the density of m-ACh.R located on the nasal mucosa. The quantity of nasal secretion induced by allergen was also correlated significantly to the density of m-ACh.R. These results suggest that the nasal hypersecretion observed in the nasal allergic model may be closely associated with an increase in the density of m-ACh.R located on the nasal mucosa.

Animals↗
PubMed1992

[A case of partial absence of the left pericardium].

A rare case of partial absence of the left pericardium was reported. The patient was a seventy-nine year old male and the cause of death was a gastric cancer. The pericardial absence was oval in shape, in egg-size with smooth margin and was located between the superior portion of the left pericardium and the pleural cavity. The pulmonary artery, left auricle and superior part of the left ventricle were visible through the absence. The left phrenic nerve descended along the anterior free margin of the absence.

Aged↗
PubMed1992

Absence of response to hypothalamic stimulation test in brain death.

Immunoreactive corticotropin-releasing hormone (CRH) and growth hormone-releasing hormone (GHRH) are present in the plasma of the brain dead patients. These hypothalamic hormones may reflect some residual brain function after brain death. To examine the hypothalamic function, insulin-induced hypoglycemia and arginine infusion were performed in brain dead patients. Plasma CRH and GHRH were present initially, but levels did not increase significantly for 120 minutes after insulin injection. GH, adrenocorticotropic hormone, and cortisol levels did not increase either. Arginine load did not induce GH. These results suggest that hypothalamic hormones in the plasma after whole brain death do not reflect hypothalamic functions. The hormones may originate from extrahypothalamic sources such as the pancreas or adrenal gland.

Adolescent↗