Laparoscopic splenectomy for immune thrombocytopenic purpura--long-term result of 40 laparoscopic splenectomies

Laparoscopic surgery has recently extended its indications and it has also become an acceptable surgical approach for splenectomy. In the last five years, we have performed 40 laparoscopic splenectomies for immune thrombocytopenic purpura. Thirty-five patients were female and 5 patients were male. The mean age was 34, varying from 17 to 56. After learning to perform laparoscopic splenectomy with five ports, we are now usually using three or four ports in a right lateral kidney position. There was no case of conversion to exploratory laparotomy. The mean hospital stay was 7 days. There was no perioperative mortality; but in 2 cases we had postoperative subphrenic abscesses which were successfully managed by catheter drainage. Since undergoing laparoscopic splenectomy, 28 patients (70%) were weaned effectively from their steroid medications. Eight patients (20%) have been on small doses of steroid, and 4 patients (10%) have been on the same doses of steroid with no response. The patient group with rapidly increasing platelet count after splenectomy showed a statistically significant relation with the complete response group (p < 0.001). Laparoscopic splenectomy is a safe and reasonable operative procedure for patients with immune thrombocytopenic purpura.

Magnesium fluoride-dependent binding of small G proteins to their GTPase-activating proteins

GTPase-activating proteins (GAPs) enhance the intrinsic GTPase activity of small G proteins, such as Ras and Rho, by contributing a catalytic arginine to the active site. An intramolecular arginine plays a similar role in heterotrimeric G proteins. Aluminum fluoride activates the GDP form of heterotrimeric G proteins, and enhances binding of the GDP form of small G proteins to their GAPs. The resultant complexes have been interpreted as analogues of the transition state of the hydrolytic reaction. Here, equilibrium binding has been measured using scintillation proximity assays to provide quantitative information on the fluoride-mediated interaction of Ras and Rho proteins with their respective GAPs, neurofibromin (NF1) and RhoGAP. High-affinity fluoride-mediated complex formation between Rho.GDP and RhoGAP occurred in the absence of aluminum; however, under these conditions, magnesium was required. Additionally, the novel observation was made of magnesium-dependent, fluoride-mediated binding of Ras.GDP to NF1 in the absence of aluminum. Aluminum was required for complex formation when the concentration of magnesium was low. Thus, either aluminum fluoride or magnesium fluoride can mediate the high-affinity binding of Rho. GDP or Ras.GDP to GAPs. It has been reported that magnesium fluoride can activate heterotrimeric G proteins. Thus, magnesium-dependent fluoride effects might be a general phenomenon with G proteins. Moreover, these data suggest that some protein.nucleotide complexes previously reported to contain aluminum fluoride may in fact contain magnesium fluoride.

Development of a robotic navigation system for neurosurgery

This paper presents a robotic navigation system for image-guided neurosurgery, which can be applied to the treatment of Parkinson's disease and biopsy of brain tumor. The system integrates a computer for real-time display of brain anatomy, a magnetic tracking device for measuring the positions and orientations of surgical instruments, and a robot manipulator for guiding surgical instruments to the preplanned positions and orientations. The computer display of brain anatomy offers a convenient tool for surgeons to diagnose brain disease and to plan safe surgical paths; while the tracking device assists the robot manipulator to automatically guide surgical instruments to the preplanned direction. The registrations among the tracking device, the image system, and the robot are completed on the base of coordination mappings of external markers. An experiment of using a skull model for simulating a robotic biopsy of brain tumor has been done to verify the performance of the navigation system. The result shows that the system can accomplish a positioning accuracy around 2 mm.

Cisatracurium neuromuscular block at the adductor pollicis and the laryngeal adductor muscles in humans

We have compared the dose-response relationship (n = 30) and time course of neuromuscular block (n = 20) of cisatracurium at the laryngeal adductor and the adductor pollicis muscles. ED95 values for cisatracurium were 66.8 (95% confidence interval 61.3-72.3) micrograms kg-1 at the larynx and 45.2 (42.1-48.3) micrograms kg-1 at the adductor pollicis muscle (P < 0.0001). After administration of cisatracurium 0.1 mg kg-1, onset time was 2.7 (2.2-3.2) min at the larynx and 3.9 (3.0-4.8) min at the adductor pollicis (P < 0.0001). Time to 95% recovery of the first twitch of the TOF was 26.9 (20.1-33.7) min and 45.6 (39.7-51.5) min, respectively (P < 0.0001). We found that the laryngeal adductors were more resistant to the action of cisatracurium than the adductor pollicis muscle, but onset and recovery were faster at the larynx.

Rabbits treated with chronic isepamicin are resistant to mivacurium and rocuronium

We compared the dose-response relationships and the neuromuscular blocking effects of mivacurium and rocuronium after chronic isepamicin therapy for 7 days in 56 anesthetized rabbits. Train-of-four stimuli were applied every 10 s to the common peroneal nerve, and the force of contraction of the tibialis anterior muscle was measured. Chronic isepamicin therapy is associated with a rightward shift of the mivacurium and rocuronium dose-response curves. The effective dose for 50% twitch depression of mivacurium and rocuronium increased significantly, from 16.9 +/- 4.8 and 56.5 +/- 5.3 microg/kg, respectively, with placebo to 30.6 +/- 5.3 and 75.6 +/- 4.7 microg/kg, respectively, during isepamicin therapy. The isepamicin rabbits receiving mivacurium 0.18 mg/kg or rocuronium 0.6 mg/kg had an accelerated recovery from neuromuscular blockade compared with those receiving placebo. The results of this study show that mivacurium and rocuronium have both a decreased effect and a shorter duration of action in rabbits when used during concurrent isepamicin therapy.

IMPLICATIONS

We studied the dose-response relationships and the neuromuscular blocking effects of mivacurium and rocuronium during chronic isepamicin therapy in rabbits. Mivacurium and rocuronium have both a decreased effect and a shorter duration of action during chronic aminoglycoside antibiotic therapy in rabbits.

Identification of a glycosaminoglycan binding surface on human interleukin-8

The activation of leukocytes by chemokines is believed to be mediated via binding of chemokines to glycosaminoglycan chains of the extracellular matrix. The binding site on the chemokine interleukin-8 (IL-8) for the glycosaminoglycan heparin has been characterized using a systematic series of site-directed mutants of IL-8 in which the basic residues of the protein have been replaced by alanine. Mutation of K64 and R68 caused the largest decrease in affinity for a heparin Sepharose matrix, with smaller effects seen with mutations of K20, R60, and K67. Heparin-derived disaccharides that could disrupt the IL-8-heparin Sepharose interaction were identified by a competitive binding assay. Heteronuclear NMR spectroscopic titration of 15N-labeled IL-8 with a trisulfated disaccharide revealed a cluster of residues on IL-8 which were perturbed by disaccharide binding. These data identify a heparin-binding surface on IL-8 that includes the C-terminal alpha-helix and the proximal loop around residues 18-23. The heparin-binding site is spatially distinct from the residues involved in receptor binding.

The effect of the nasopharyngeal air cavity on x-ray interface doses

We investigated the impact of air cavities in head and neck cancer patients treated by photon beams based on clinical set-ups. The phantom for investigation was constructed with a cubic air cavity of 4 x 4 x 4 cm3 located at the centre of a 30 x 30 x 16 cm3 solid water slab. The cavity cube was used to resemble an extreme case for the nasal cavity. Apart from measuring the dose profiles and central axis percentage depth dose distribution, the dose values in 0.25 x 0.25 x 0.25 cm3 voxels at regions around the air cavity were obtained by Monte Carlo simulations. A mean dose value was taken over the voxels of interest at each depth for evaluation. Single-field results were added to study parallel opposed field effects. For 10 x 10 cm2 parallel opposed fields at 4, 6 and 8 MV, the mean dose at regions near the lateral interfaces of the cavity cube were decreased by 1 to 2% due to the lack of lateral scatter, while the mean dose near the proximal and distal interfaces was increased by 2 to 4% due to the greater transmission through air. Secondary build-up effects at points immediately beyond the air cavity cube are negligible using field sizes greater than 4 x 4 cm2. For most head and neck treatment, the field sizes are usually 6 x 6 cm2 or greater, and most cavity volumes are smaller than our chosen dimensions. Therefore, the influence of closed air cavities on photon interface doses is not significant in clinical treatment set-ups.

Conformational analysis of neuropeptide Y segments by CD, NMR spectroscopy and restrained molecular dynamics

Neuropeptide Y (NPY), a peptide amide comprising 36 residue has been shown to act as a potent vasoconstrictor. In order to shed light on the structural requirements for the biological activities with respect to the different prerequisites for affinity to the NPY receptor subtypes Y1 and Y2, in the present study the syntheses and conformational analyses of two C-terminal segments, NPY(18-36) and NPY(13-36), are described. The results obtained by CD measurements, two-dimensional NMR spectroscopy and a conformational refinement of the NMR-derived structure by molecular mechanics stimulations support the findings of previously published structure-activity relationship studies for biologically active and selective compounds. In particular, the alpha-helical conformation as well as an appropriate exposure of the side chains of the critical C-terminal dipeptide within NPY(18-36) are in agreement with the prerequisites proposed for Y2 receptor binding of that segment.

Selectivity and antagonism of chemokine receptors

The chemokine superfamily can be subdivided into two groups based on their amino terminal cysteine spacing. The CXC chemokines are primarily involved in neutrophil-mediated inflammation and, so far, two human receptors have been cloned. The CC chemokines tend to be involved in chronic inflammation, and recently we have cloned a fourth leukocyte receptor for this group of ligands. Understanding what makes one receptor bind its range of agonists is important if we are to develop potent selective antagonist. We have started to investigate the molecular basis of this receptor selectivity by looking at why CC chemokines do not bind to the CXC receptors in several ways. First, we looked at the role of the three-dimensional structure of the ligand, and have solved the three dimensional structure of RANTES using nuclear magnetic resonance spectroscopy. The structure is similar to that already determined for the CC chemokine macrophage inflammatory protein-1 beta, and it has a completely different dimer interface to that of the CXC chemokine interleukin-8 (IL-8). However, the monomer structures of all the chemokines are very similar, and at physiological concentrations the proteins are likely to be monomeric. Second, by examining all the known CC and CXC chemokines, we have found a region that differs between the two subfamilies. Mutations of one of the residues in this region, Leu-25 in IL-8, to tyrosine (which is conserved at this position in CC chemokines) enables the mutant IL-8 to bind CC chemokine receptor-1 (CC-CKR-1) and introduces monocyte chemoattractant activity. Using other mutations in this region, we can show a direct interaction with the N-terminus of CC-CKR-1. Third, we have found that modification of the amino terminus of RANTES by addition of one amino acid makes it into an antagonist with nanomolar potency. Taken together, this data suggests a two-site model for receptor activation and for selectivity between CC and CXC chemokines, with an initial receptor contact provided by the main body of the chemokine, and activation provided by the amino terminal region.

Peptidergic innervation of the primate meibomian gland

PURPOSE

To localize and characterize nerves in primate meibomian glands using immunohistochemical staining for neuropeptides and neuronal enzymes.

METHODS

Upper eyelids were obtained from seven rhesus monkeys (Macaca mulatta) and one cynomolgous monkey (Macaca fascicularis). The tissues were fixed either by immersion in Zamboni's fixative or by transcardiac perfusion with paraformaldehyde and glutaraldehyde and were then postfixed. Cryostat tissue sections of the lids were stained by immunohistochemistry using rabbit antisera to neuron-specific enolase (NSE), tyrosine hydroxylase (TH), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), and substance P (SP), followed by a fluorescence visualization system.

RESULTS

Used as a marker for the overall nerve distribution, NSE antibodies revealed abundant smooth and varicose nerve fibers closely apposed to the basement membranes of acini of the meibomian glands. Numerous nerve fibers near the meibomian gland acini were immunoreactive for NPY and VIP, but nerve fibers containing TH, CGRP, and SP were more sparse in the meibomian glands. Nerve fibers also were visualized in other eyelid structures, including conjunctiva, epidermis, hair follicles, and subconjunctival lymphoid follicles.

CONCLUSIONS

The meibomian glands of rhesus and cynomolgous monkeys are richly innervated by diverse nerve fiber types. The immunohistochemical staining suggests a largely parasympathetic origin for this innervation, with relatively smaller contributions from sympathetic and sensory sources. These findings also suggest that meibomian gland secretion is under the control of diverse neurotransmitter-neuromodulator mechanisms.

Pulmonary artery aneurysm presenting as a lung mass

We describe a case of pulmonary artery aneurysm in which clinical clues and conventional imaging suggested a lung tumor, and the actual nature of the lesion was discovered at the time of thoracotomy. This case shows the importance of an awareness of this condition in the formulation of a differential diagnosis for a lung mass.

The three-dimensional solution structure of RANTES

The solution structure of the chemokine RANTES (regulated on activation, normal T-cell expressed and secreted) has been determined using NMR spectroscopy. Backbone and side-chain 1H and 15N assignments have been obtained using a combination of two-dimensional homonuclear and three-dimensional heteronuclear spectra. Regular elements of secondary structure have been identified on the basis of a qualitative interpretation of NOE data, J(NH-H alpha) coupling constants, and amide exchange rates. Three-dimensional structures were calculated from a total of 2146 experimental restraints using a combination of distance geometry and simulated annealing protocols. For the 13 best structures the average backbone (N, C alpha, C) atomic rmsd from the mean coordinates for residues 5-65 is 0.64 A (+/- 0.14 A) for the dimer and 0.50 A (+/- 0.08 A) for the individual monomers. Each monomer consists of a three-stranded antiparallel beta-sheet (residues 26-30, 38-43, 48-51) in a Greek key motif with a C-terminal helix (56-65) packed across the sheet, an arrangement similar to the monomeric structure of other members of this chemokine family (IL-8, PF4, MGSA/Gro alpha, and MIP-1 beta). Overall, the RANTES dimer resembles that previously reported for MIP-1 beta.

Health insurance and utilization of medical care for children with special health care needs

Based on analyses of the 1988 National Center for Health Statistics, National Health Interview Survey, Child Health Supplement, this study examines the insurance coverage and utilization of physicians, hospitals, and prescribed medicine among the 9.6 million U.S. children with special health care needs, defined as children who had one or more selected chronic conditions that caused them to experience pain, discomfort, or being upset often or all of the time in the last year, or who were limited in their major childhood activities (playing or going to school) as a result of these or other impairments or health problems. The findings confirmed that substantial variation in access to routine medical care exists among these children. Though health status is an important predictor of which children use services in general, poor, minority children who lived with their mother or someone other than their parents, or those without insurance or an identifiable regular medical provider were most likely to experience financial barriers to access or were less apt to seek care than other children with comparable needs. Access to routine medical care remains particularly problematic for these subsets of children with special health care needs.

Evaluation of antioxidant treatment with superoxide dismutase in rat liver transplantation after warm ischemia

In order to investigate the effects of the exogenously administered radical scavenger superoxide dismutase (SOD) on the orthotopic liver graft, livers from male Wistar rats were transplanted after subjection to 40 min of warm ischemia and 30 min of storage at 4 degrees C. SOD was given at the onset of ischemia and before reperfusion as a supplement (6,000 IU) to the washout solutions. 30,000 IU were infused into the recipient. SOD reduced tissue levels of thiobarbituric acid-reacting substances at the end of ischemia (737 vs. 956 nmol/g; p < 0.01) and 60 min after the onset of reperfusion (629 vs. 947 nmol/g; p < 0.001) and preserved total adenine nucleotides after reperfusion (11.69 vs. 10.40 mumol/g; p < 0.01). Survival 2 weeks after transplantation was 18% (2/11) in the SOD group versus 10% (1/10; nonsignificant) in untreated animals. It is concluded that SOD protects the ischemically altered liver from radical mediated peroxidation and preserves hepatic energy stores upon reperfusion. However, in our model no major improvement in organ viability could by achieved.

Comparison of hepatitis B virus subtyping ofd/y determinants by radioimmunoprecipitation assay and the polymerase chain reaction

Using a double polymerase chain reaction a method was devised for detecting and subtyping hepatitis B virus DNA in serum samples. Primers from the S-gene were selected from the sequence analyses of five HBV HBsAg subtypes, to amplify HBV DNA and subtype for y specific DNA. Thirty-eight samples were subtyped for d and y determinants by radioimmunoprecipitation assay (RIPA) and the polymerase chain reaction (PCR). Subtyping by PCR and RIPA was in agreement in 100% of subtype y samples and 83.3% of subtype d, giving an overall correlation of 92.1%. As a third comparison, 12 amplified samples were digested by the restriction enzyme Sau 3A, which differentiates between subtypes y and d. The digest results agreed with PCR in 83.3% of the samples. In addition, we compared our standard phenol/chloroform extraction against a rapid one step method. The phenol/chloroform stage was found to be essential for the removal of nucleases and polymerase inhibitors present in sera.

A case of Leigh's disease with initial manifestation of dystonia

A case of Leigh's disease (subacute necrotizing encephalomyelopathy) is reported with such noteworthy features as early onset, dystonia, paraparesis the presence of low attenuation areas in both basal ganglias on computerized tomography of the brain and the presence of a high signal intensity in both basal ganglias in T2 weighted image by MR. The electron microscopic findings of muscle biopsy are suggestive of pleoconial mitochondrial myopathy.

Method of determining kidney position as guide for percutaneous nephrostomy

Computed tomography scans were used to assess the distance between the skin and the collecting system in 256 kidneys in 128 adult patients of various heights and weights. Body surface area correlated well with kidney depth. A graph is presented that can be used to calculate kidney depth.

Sensitization potentials of methyl, ethyl, and n-butly methacrylates and mutual cross-sensitivity in guinea pigs

Guinea pigs could be strongly sensitized to methyl, ethyl, and n-butyl methacrylates in ethanol or olive oil by the topical route, or in saline by the intradermal route. For elicitation of skin reactons, topical challenge with the compounds in olive oil or intradermal challenge with saline as the solvent was neccessary. Topical challenge with the methacrylates in ethanol failed to elicit any allergic skin reactions because of their volatility. All sensitized animals responded strongly not only to the inducing methacrylate but also to the other methacrylates, showing that mutual cross-sensitivity had occurred. Since methyl methacrylate has been reported to be a potent sensitizer in humans, the guinea-pig model described here may be useful for screening products before marketing.

Cross-sensitivity of common aminoglycoside antibiotics

Guinea pigs were sensitized to neomycin (A, B, or C), paromomycin, gentamicin, kanamycin, streptomycin, and dihydrostreptomycin via intradermal or foot-pad injection with an adjuvant containing killed Mycobacterium butyricum or M tuberculosis H37Ra (Ra). These antibiotics produced greater cross-sensitization with an increase in the number of immunizations and chemical structural similarities. After repeated intradermal injections (adjuvant Ra) of neomycin, guinea pigs showed cross-sensitization to paromomycin, kanamycin, and streptomycin. A single intradermal injection of one of these antibiotics produced stronger reactions to the most closely related antibiotics, with no meaningful sensitization to the least-related allergens. Streptomycin-sensitized guinea pigs seldom showed a meaningful cross-sensitization to dihydrostreptomycin or the other antibiotics (except neomycin C); however, guinea pigs sensitized to dihydrostreptomycin or the other antibiotics often showed strong cross-sensitization to streptomycin.

Dermal carcinogenicity study by mouse-skin painting with 2,4-toluendediamine alone or in representative hair dye formulations

The chronic toxicity of 2,4-toluenediamine (2,4-TDA) alone or in conbination with a hair dye complex (2,5-toluenediamine, p-phenylenediamine, and resorcinol) was studied in Swiss-Webster mice of both sexes by a skin-painting technique. The predominant neoplasms seen in these mice were primary pulmonary adenomas and adenocarcinomas. Skin neoplasms were seen in most groups of mice, including untreated control mice. Statistical analysis of the incidences of skin neoplasms among the various groups of mice did not show any significant differences. The 2,4-TDA alone or mixed with the hair dye complex did not produce any abnormal proliferation and maturation of the squamous epithelium of the skin. The 2,4-TDA under our experimental conditions was found to be nontoxic and noncarcinogenic to the skin of mice.

Sensitization potentials and immunologic specificities of neomycins

The use of sensitization indices for expressing allergenic skin reactions in guinea pigs is described. The method is convenient for comparing allergens and cross-reacting substances and permits the use of both irritating and nonirritating challenge concentrations of allergens. It also permits determination of both optimal reading time and challenge concentrations for each experiment. By this technique commercial neomycin complex, neamine (neomycin A), neomycin B, neomycin C, and streptomycin were found to be allergenic in guinea pigs via intradermal (id) and foot-pad (fp) immunizations. The immunizing emulsion consisted of an allergen and an adjuvant containing Mycobacterium butyricum (MB) or Mycobacterium tuberculosis H37Ra (Ra). The adjuvant MB was as effective as Ra by the id route, but inferior to Ra by the fp route. The cross-reactivity of neomycin C was generally greater than neomycin B in guinea pigs sensitized to neamine, neomycin B, neomycin C, or streptomycin. In guinea pigs sensitized to neomycin complex by repeated immunizations, neomycins A, B, and C were effective elicitors of skin reactions, whereas the N-acetylated derivatives of the components failed to cause reactions. This finding is interpreted to mean that the amino groups of the aminoglycosides are the coupling sites to host proteins in the processes of sensitization and elicitation of skin reactions in vivo.