Neurochemical and morphological responses to acutely and chronically implanted brain microdialysis probes

The purpose of this study was to compare, in rats, brain microdialysis results obtained using microdialysis probes implanted acutely for 2 h versus probes implanted chronically for 24 h in the caudate. Specific comparisons included: (1) dialysate purine and amino acid profiles during cerebral ischemia; (2) diffusional characteristics of the microdialysis probe; and (3) tissue morphology surrounding the probe. During ischemia, the increase in dialysate levels of adenosine, inosine, and hypoxanthine was less pronounced from probes implanted chronically, while dialysate xanthine levels increased to a greater extent. An increase in dialysate amino acid neurotransmitters during cerebral ischemia was observed in the acutely implanted probes within 10 min of the onset of cerebral ischemia; in the chronically implanted probes this increase did not occur until after 50 min of severe ischemia. Both in vitro and in vivo tests revealed a diffusional barrier in chronically implanted probes. Moreover, the tissue surrounding chronically implanted probes exhibited a high degree of inflammation, and fibrin deposits were substantial. In addition, uric acid levels (an indicator of tissue injury) sampled from chronically implanted probes were 7-fold greater than levels sampled from acutely implanted probes. These data raise concerns about the use of chronically implanted microdialysis probes for the measurement of purine and amino acid profiles during cerebral ischemia.

Risperidone for aggression and self-injurious behavior in adults with mental retardation

Risperidone has proven efficacy with reduced likelihood of causing extrapyramidal symptoms in the treatment of schizophrenia. Initial work suggests its utility in the management of aggression and self injury in patients with mental retardation. The use of risperidone in eight adult patients with moderate to profound mental retardation is described. Risperidone in these individuals was associated with significant reduction in aggression and self injurious behavior. Side effects were primarily those of sedation and restlessness. These cases illustrate the possible utility of risperidone in the treatment of aggression and self injury in adult patients with moderate to profound mental retardation.

Cellular effects of hypercholesterolemia in modulation of cancer growth and metastasis: a review of the evidence

Hypercholesterolemia and increased cancer risk have been associated, particularly with the high fat diets characteristic of Western societies. We were interested in the possible association between preexisting hypercholesterolemia and the rapidity and extent of tumor metastases in these patients. To date there has been only a few studies that have suggested and explored this determinant of cancer metastases although it may play a role in a subset of patients who develop cancers. This article will review the literature on the effects of LDL-cholesterol on cell proliferation and differentiation and speculate on mechanisms of involvement of a hypercholesterolemic milieu on cancer progression and enhancement of metastatic potential.

Gallbladder and biliary tract disease in AIDS

Biliary disease occurs in a subset of AIDS patients with CD4 counts of less than 100 per mm3. These patients present with right upper quadrant and epigastric pain, cholestasis, and usually abnormal findings on imaging. In 75% of patients, an associated opportunistic infection can be identified. In patients with biliary disease, pain is often relieved following endoscopic sphincterotomy, whereas cholecystectomy provides pain relief in patients with acalculous cholecystitis.

Sodium channel distribution within the rabbit atrioventricular node as analysed by confocal microscopy

1. Paired 20 microns thick sections of fresh frozen tissue taken from the frontal plane of the rabbit atrioventricular (AV) nodal region were processed for histology and immunohistochemistry. Confocal microscopy was used to image the distribution of sodium channels using IgG (R12) developed against a highly conserved sequence in the interdomain 3-4 region of cloned sodium channels. 2. In ventricular and atrial cells, sodium channel immunofluorescence was localized to lateral membranes and T-tubules. In the open AV node, levels of sodium channel immunofluorescence in the transitional cell zone and in the lower nodal cell tract were comparable to that found in the atrial and ventricular myocardium. 3. In the enclosed AV node a gradation of sodium channel immunofluorescence is present such that peripherally located circumferential transitional cells display high levels of immunofluorescence, comparable to that of atrial and ventricular myocardium, while centrally located midnodal cells display decreased levels of or no immunofluorescence. 4. In order to correlate the distribution of sodium channels with the distribution of gap junctions, we used IgG directed against the carboxyl terminus of connexin43 (CT-360). Ventricular cell immunofluorescence was localized primarily to the intercalated disk region, while in the AV node, the pattern of distribution was found to be similar to that of sodium channels. 5. The reduced levels of and/or absence of immunofluorescence in the midnodal cell region indicates a paucity of sodium channel and connexin43 protein expression in this region of the AV node that would favour slow impulse conduction.

Hrp12, a novel heat-responsive, tissue-specific, phosphorylated protein isolated from mouse liver

Previous studies from this laboratory identified a 28-kd nonreducible protein, liver-derived immunoinhibitory factor (LDIF) from the mouse liver. Isolation of this protein resulted in the co-purification of another unique protein called heat responsive protein 12 kd (Hrp12). In contrast to LDIF, Hrp12 was totally reducible to a protein of 12 kd suggesting a dimer. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) purification, followed by sequencing of an in situ cyanogen bromide digest of membrane bound Hrp12, yielded an internal 20-amino acid polypeptide. Degenerate oligonucleotides made from this peptide were used to screen a murine liver complementary DNA (cDNA) library. A 1240-bp cDNA clone was obtained with an internal 521-bp open reading frame (ORF). Sequence analysis of the 173-amino acid ORF of mouse Hrp12 showed a high degree of homology with a 99 amino acid rat liver-kidney perchloric acid-soluble protein (LKPS) and a 136-amino acid perchloric acid soluble rat protein (PSP). Transcripts for Hrp12 were mainly restricted to the liver and kidney in mouse and man. The protein was estimated to be approximately 0.8% of the total liver-soluble cytosolic protein. A zoo-blot probed at moderate stringency with labeled cDNA revealed a strong conservation of the gene in all of the mammalian species tested. Analysis of the protein structure of Hrp12 revealed motifs predicted to be targets for protein kinase C (PKC). More importantly, purified mouse Hrp12 could be phosphorylated in vitro with PKC. The protein had significant similarity to DnaK heat shock protein (Hsp)70 and contained a 54-amino acid stretch with sequence similarity to Hsp90. This prompted us to investigate the heat shock response of Hrp12. Isolated hepatocytes and hepatoma cells were exposed to different heat shock temperatures (39.5 degrees C, 42.5 degrees C, and 44.5 degrees C); and then total RNA was extracted and Northern analysis carried out. The message for this novel protein responded atypically to heat shock. Although the steady-state level of the message increased after heat shock, a marked oscillatory pattern was superimposed on it. In contrast, the steady-state levels of Hsp90 and Hsp70 messenger RNA (mRNA) were found to respond to heat shock in the expected manner. Finally, the amount of Hrp12 protein was also found to increase after heat shock in a manner that was consistent with heat-responsive proteins.

Immunocytochemical localization of rH1 sodium channel in adult rat heart atria and ventricle. Presence in terminal intercalated disks

BACKGROUND

Of the five sodium channel subtypes expressed in cardiac tissues, the rat (rH1) and human (hH1) isoforms are thought to be the predominant subtypes on the basis of heterologous expression studies. In this study, subtype-specific antibodies and immunocytochemistry were used to confirm protein expression and to localize rH1 protein in cardiac tissues.

METHODS AND RESULTS

Subtype-specific antibodies immunolabeled adult rat heart tissue in a manner identical to that obtained with subtype-nonselective antibodies. All antibodies specifically bound to the surface and t-tubular systems of atrial and ventricular muscle cells. Cytoplasmic labeling, reflecting nascent sodium channels or cytoplasmic stores of sodium channel protein, was apparent. Most notably, all antibodies also specifically labeled the subset of intercalated disks located at the ends but not the sides of adjacent ventricular muscle cells.

CONCLUSIONS

rH1 is the predominant subtype expressed on rat atrial and ventricular muscle cells. rH1 protein localization in surface and t-tubular membranes is consistent with its proposed role in coordinating membrane depolarization along the length and deep within cardiac muscle cells. rH1 protein localization in terminal intercalated disks suggests that sodium channels may also act as a localized voltage-dependent current amplifier, raising the safety margin for conduction; they also may contribute to anisotropic or saltatory conduction in cardiac tissues. These electrophysiological properties would be particularly important under conditions of altered, channel function resulting from ion channel gene defects (e.g., long QT syndrome), antiarrhythmic drug therapy, ischemia, or other heart diseases by influencing the electrophysiological substrate for ventricular tachyarrhythmias.

Levamisole regulates the proliferation of murine liver T cells through Kupffer-cell-derived cytokines

We have previously shown that levamisole increases the cytotoxic, cytostatic, and proliferative activity of murine nonparenchymal liver cells (NPC) in vitro. We have also shown that the nonadherent subpopulation of NPC, which are composed predominantly of T lymphocytes, is very responsive to this agent when administered to mice. Kupffer cells or immigrant macrophages are also responsive to levamisole but to a lesser extent. These findings prompted us to investigate changes in cytokine production by NPC following-treatment of mice with levamisole (25 mg/kg, i.p.), which may help explain the observed alterations in the immune functions of these cells. We found that levamisole treatment of mice causes a threefold increase in production of interferon (IFN) alpha/beta by adherent NPC (more than 80%-90% Kupffer cells) in vitro. When IFN alpha/beta was added to cultured cells, it decreased the proliferative capacity of liver T cells in a dose-dependent manner. In contrast, the addition of anti-IFN alpha/beta was shown to augment levamisole-induced proliferation of unfractionated NPC and Kupffer cells. NPC production of interleukin 1 (IL-1) and interleukin-6 (IL-6) in vitro was also increased threefold following treatment of mice with levamisole. IL-6 added in vitro to cells significantly augmented levamisole-induced proliferation of liver T cells while anti-IL-6 reduced proliferative activity to control levels. These findings suggested that IFN alpha/beta, IL-6, and IL-1 play important regulatory roles in controlling the proliferative response of murine liver-associated T lymphocytes to levamisole. Finally, the proliferation of bone marrow cells was increased in mice given 5-fluorouracil (5FU). On the other hand, the proliferation of NPC was dramatically suppressed when 5FU was administered. However, the proliferation of these cells was restored when levamisole was given after 5FU.

Prechallenge antibodies: moderators of infection rate, signs, and symptoms in adults experimentally challenged with rhinovirus type 39

This study determined the influence of serum neutralizing antibody titers on infection rate, symptom manifestations, and provoked signs and pathophysiologies in adults experimentally exposed to rhinovirus type 39 (RV-39). Antibody status was determined for 151 healthy volunteers who were then cloistered in a hotel for 6 days. At the end of the first cloister day, the volunteers were challenged with RV-39 in a median tissue culture infective dose of 100. On each of the 6 days, a nasal examination was performed, symptoms were scored, and objective tests of nasal mucociliary function, nasal airway patency, secretion production, and middle ear pressures were completed. Both subjects and investigators were blinded to the prechallenge serum homotypic antibody titers of the subjects. Four subjects presented with a wild virus and were excluded from the analysis. Of the 147 included subjects, prechallenge serum antibody titers to RV-39 were low (under 2) in 56 subjects, intermediate (2 to 8) in 51 subjects, and high (above 16) in 40 subjects. The high-titer group was significantly different from the low-titer group with respect to viral shedding, symptom load, subjective extent of illness, and secretion production, as well as in the frequency of subjects with abnormal nasal mucociliary clearance and positive middle ear pressures. The study results document that for experimental RV-39 exposure, high levels of homotypic serum neutralizing antibody titers are associated with protection from infection and a lessened degree of disease expression, but not with a reduction of otologic complications.

Complications of diagnostic and therapeutic ERCP

Complications associated with ERCP have been well defined, clinically recognized, and effectively managed conservatively. Few patients require surgery or prolonged hospitalization. The morbidity and mortality associated with ERCP and sphincterotomy have remained low, and, although the outcome of endoscopy is equivalent or better than surgical or radiologic techniques, the complications are less. Despite the general acceptance of ERCP, its therapeutic applications, its more universal performance, and the morbidity and mortality rates have remained the same or lower since its introduction a quarter of a century ago.

Needle-knife sphincterotomy in a tertiary referral center: efficacy and complications

BACKGROUND

The use of needle-knife sphincterotomy as a method of precut sphincterotomy has been criticized as potentially unsafe. Despite this, a number of tertiary referral centers have reported their successful use of this technique to increase the rate of common bile duct cannulation.

METHODS

We assessed the safety and efficacy of needle-knife sphincterotomy in 72 consecutive patients in whom attempts at standard common bile duct cannulation were unsuccessful. Bile duct diameters were correlated to the complication rate.

RESULTS

Cannulation of the common bile duct was successful immediately after needle-knife sphincterotomy in 50 patients (67%), and was successful in 17 of the 20 patients who underwent repeat ERCP, for a total cannulation rate of 93%. Eight patients (11%) experienced complications. Retroduodenal perforation during guide wire cannulation attempts and bleeding occurred as frequently as pancreatitis. Small duct size was a risk factor for complications. There was no procedure-related mortality, and all complications were managed medically.

CONCLUSIONS

Needle-knife sphincterotomy was effective in facilitating cannulation in patients in whom standard cannulation attempts failed. Limiting guide wire manipulation of the fresh sphincterotomy site and excluding patients with small duct size may further reduce the complication rate.

The chemokine C10: immunological and functional analysis of the sequence encoded by the novel second exon

The gene for C10, a member of the beta-chemokine family of cytokines, contains a novel second exon encoding a 16 amino acid sequence which is inserted into the amino-terminal region of the protein. We propose a model of C10 structure in which the sequence encoded by the second exon is located on the surface of the protein where it interacts with receptors and defines the predominant epitope of the C10 protein. To test this model we produced C10 protein without the sequence encoded by the second exon, termed C10(-). Antisera generated against purified C10 recognized C10 protein but reacted only weakly with C10(-) protein. Recognition of C10 protein by C10 antisera was not blocked by pre-incubation with a peptide encoding the C10 second exon, indicating that the predominant epitope was not simply the amino acid sequence encoded by the second exon. Antibodies generated against a peptide encoding the C10 second exon sequence recognized C10 on Western blots; this reaction was competed both by C10 second exon peptide and by C10 protein. Functional studies demonstrated that both C10/FLAG and C10(-)/FLAG elicit chemotaxis of mouse PECs and human PBMCs, but that C10(-)/FLAG appears to be more potent than C10/FLAG. Thus these data are consistent with our model of C10 in which the sequence encoded by the second exon is located on the surface, participates in defining the predominant epitope, and plays a key role in recognizing or activating chemokine receptors.

Electrochemical activity of 6-aminoquinolyl urea derivatives of amino acids and peptides. Application to high-performance liquid chromatography with electrochemical detection

6-Aminoquinolyl-N-hydroxysuccinimidyl carbamate (6-AQC) is a reagent used to increase the detection-sensitivity of amino acids and peptides in high-performance liquid chromatography with fluorescence detection. In this paper, the electrochemical characteristics of the derivatives of 6-AQC are described. Electrochemical detection of 6-AQC amino acids and peptide derivatives following reverse-phase HPLC are also reported. The response linearity of the derivatives on an amperometric detector was studied in the range of 5 pmol (0.5 mu M) to 2500 pmol (250 mu M). Approximately 2.5 pmol of the amino acid derivatives could be detected. The quantitative results of amino acids in plasma and a bovine serum albumin hydrolysate agreed well with values reported in the literature.

Probing sodium channel cytoplasmic domain structure. Evidence for the interaction of the rSkM1 amino and carboxyl termini

Epitopes for monoclonal antibodies directed against the purified adult rat skeletal muscle sodium channel (rSkM1) were localized using channel proteolysis and fusion proteins. The interactions between these and other monoclonal antibodies with site-specific polyclonal antibodies were used to investigate the spatial relationships among rSkM1 cytoplasmic segments. Competition. between antibodies for binding was performed using a solution-phase assay in which solubilized channel protein retains many of the biophysical characteristics of the rSkM1 protein in vivo. Our results support a model in which: 1) the amino terminus assumes a rigid structure having a fixed orientation with respect to other intracellular segments; 2) the interdomain 2-3 region is centrally located on the cytoplasmic surface of the channel, extends farther into the cytoplasm, and has an intermediate degree of flexibility; 3) the beginning of the amino terminus and end of the carboxyl terminus specifically interact with each other; and 4) domains 1 and 4 are adjacent. The sequences responsible for the interaction of the amino and carboxyl termini were identified by demonstrating the specific binding of a synthetic peptide encompassing the first 30 residues of the rSkM1 amino terminus to a fusion protein containing the rSkM1 carboxyl terminus.

Persistence of the gallbladder following laparoscopic cholecystectomy: a case report

Laparoscopic cholecystectomy is the technique of choice for cholecystectomy. No experience with congenital abnormalities of the gallbladder has been reported. We report here the case of a 42-year-old woman who developed recurrent symptoms seven months after laparoscopic cholecystectomy and was found to have the majority of her gallbladder still intact. We speculate that the patient had a bilobate gallbladder as the explanation for the mishap. She subsequently underwent open repeat surgery.

Biliary tract emergencies. Endoscopic and medical management

The application of therapeutic ERCP and interventional radiology has significantly altered the treatment of biliary tract emergencies. Although surgery is the principal treatment for acute cholecystitis, nonoperative alternatives exist for high-risk patients. New, prospective, randomized trials have demonstrated that endoscopic management of severe cholangitis is superior to surgery, and that endoscopic sphincterotomy and stone extraction are superior to conservative treatment in severe gallstone pancreatitis. ERCP allows nonoperative management of postoperative bile leaks as well.

Therapeutic pancreaticobiliary endoscopy

The remarkable advances achieved in the performance of therapeutic endoscopic retrograde cholangiopancreatography have placed endoscopy in the forefront in the schema for treating pancreaticobiliary disorders. Since the introduction of sphincterotomy and its impact on the management of stone disease, we have seen rapid development of alternative methods for treating obstructive jaundice, neoplasia of the biliary tree, and benign disorders. In addition, endoscopists are treating strictures and fistulas of the bile duct and pancreas, gallbladder disease, and more spectacularly, gallstone pancreatitis. Endoscopic therapy compares favorably with surgery in managing cholangitis, and it is the treatment of choice for many disorders affecting the biliary tree and the pancreas. Because of the safety, efficacy, and cost-effectiveness of endoscopy, the demand for increasing the spectrum of disorders continues. We discuss techniques and results of endoscopic treatment of a broad range of diseases.