Impaired glucose-stimulated insulin secretion, enhanced intraperitoneal insulin tolerance, and increased beta-cell mass in mice lacking the p110gamma isoform of phosphoinositide 3-kinase.

Phosphoinositide 3-kinase (PI3 kinase) has been implicated in G protein-coupled receptor regulation of pancreatic beta-cell growth and glucose-stimulated insulin secretion. The G protein-activated p110gamma isoform of PI3 kinase was detected in insulinoma cells, mouse islets, and human islets. In 7- to 10-wk-old mice, knockout of p110gamma reduced the plasma insulin response to ip glucose injection and impaired first and second phase glucose-stimulated insulin secretion from pancreata perfused ex vivo. The p110gamma -/- mice responded to preinjection with the glucagon-like peptide-1 receptor agonist exendin 4, such that plasma glucose and insulin responses to ip glucose injection were not different from wild types. Mice lacking p110gamma were not diabetic and were only slightly glucose intolerant (ip glucose injection) compared with wild types, in part due to enhanced responsiveness to insulin as determined by an ip insulin tolerance test. Despite severely reduced insulin secretion in these animals, the p110gamma -/- mice had greater pancreatic insulin content, and an increased beta-cell mass due to beta-cell hypertrophy. These surprising results suggest that the G protein-coupled p110gamma isoform of PI3 kinase is not central to the development or maintenance of sufficient beta-cell mass but positively regulates glucose-stimulated insulin secretion.

Determinants of acute regional toxicity following isolated limb perfusion for melanoma.

Hyperthermic isolated limb perfusion (ILP) with melphalan is well established as an effective form of treatment for recurrent melanoma confined to an extremity. High drug concentrations in the limb are readily achieved, without systemic side-effects. However, regional toxicity can lead to considerable morbidity and functional disturbance. This study was undertaken to evaluate factors which might contribute to acute regional toxicity following ILP. Melphalan concentrations in limb blood samples taken at regular intervals during 135 ILPs were measured by HPLC, allowing peak melphalan concentration and area under the curve (AUC) for each procedure to be determined. Acute regional toxicity associated with ILP was found to be significantly correlated with limb tissue temperatures > 40 degrees C, peak melphalan concentration and melphalan AUC, in decreasing order, but was not correlated with tourniquet time. Further studies are required to directly assess melphalan uptake by tumour tissue, and to relate this to both limb toxicity and tumour response.

Elevated plasma vitamers of vitamin B6 in patients with chronic renal failure on regular haemodialysis.

Plasma pyridoxal-5'-phosphate (PL-5'-P), pyridoxal (PL), pyridoxine (PN), and 4-pyridoxic acid (4-PA) were measured by high-performance liquid chromatography (HPLC) in 39 patients (15 male, 24 female) with chronic fenal failure undergoing regular haemodialysis and 46 healthy controls (28 male, 18 female). All three vitamers of vitamin B6 and the metabolite were significantly elevated in the haemodialysis patients. Mean PL-5'-P and PN concentrations were 20 times the mean in controls. Only one patient took a vitamin B6 supplement. In view of the neurotoxicity of supranutritional intakes of PN in normal humans we suggest that supplements of PN be carefully monitored when administered to patients with chronic renal failure.

Effect of Ku86 and DNA-PKcs deficiency on non-homologous end-joining and homologous recombination using a transient transfection assay.

In mammalian cells, DNA double-strand breaks are repaired by non-homologous end-joining and homologous recombination, both pathways being essential for the maintenance of genome integrity. We determined the effect of mutations in Ku86 and DNA-PK on the efficiency and the accuracy of double-strand break repair by non-homologous end-joining and homologous recombination in mammalian cells. We used an assay, based on the transient transfection of a linearized plasmid DNA, designed to simultaneously detect transfection and recombination markers. In agreement with previous results non-homologous end-joining was largely compromised in Ku86 deficient cells, and returned to normal in the Ku86-complemented isogenic cell line. In addition, analysis of DNA plasmids recovered from Ku86 mutant cells showed an increased use of microhomologies at the nonhomologous end joining junctions, and displayed a significantly higher frequency of DNA insertions compared to control cells. On the other hand, the DNA-PKcs deficient cell lines showed efficient double-strand break repair by both mechanisms.

Observer-blinded comparison of two nonopioid analgesics for postoperative pain in piglets.

Piglets are popular for studies of respiratory and cardiovascular function, but opioid analgesics are contraindicated in these studies because of central nervous system depression. We evaluated two nonopioid analgesics for postoperative pain relief following implantation of a central arterial catheter via an inguinal incision. Animals were randomly assigned to paracetamol-treated (n=8, rectal suppositories, 100 mg/kg) meloxicam-treated (n=8, 1 mg/kg meloxicam via the catheter) or untreated control group (n=8, placebo suppositories and normal saline). Additional controls received paracetamol or meloxicam, without pain (n=6 for both groups). Behavioral and physiological assessments, and blood sampling were undertaken at nine timed intervals until 24 h after surgery. Multifactorial numerical rating scale (NRS), behavioral and physiological pain scores (PPS) decreased over time for all groups (P<.001). On NRS and behavioral criteria, meloxicam was significantly better than paracetamol (P<.001), and both were better than control (p<.001 for each). Physiological parameters discriminated between the control and analgesia-treated groups, but not between paracetamol and meloxicam. Preliminary pharmacokinetics, determined by isocratic high-performance liquid chromatography (HPLC), revealed no difference in the half-life of paracetamol (2.5+/-0.3 h) vs. meloxicam (3.4+/-0.4 h). Paracetamol and meloxicam provided effective postoperative analgesia in piglets, with meloxicam superior to paracetamol on behavioral criteria.

Stability of cyclosporine in an extemporaneously compounded paste.

The stability of cyclosporine in an extemporaneously compounded paste was studied. Cyclosporine oral solution 100 mg/mL was mixed with an adhesive gel to prepare six aluminum-lined ointment tubes containing paste with cyclosporine 9.6 mg/g. Two of the tubes were stored at 37 degrees C, two at 21 degrees C, and two at 2 degrees C. Cyclosporine was extracted from samples taken on days 2, 4, 5, 7, 9, 14, 18, 22, 28, and 31, and the concentration was measured by high-performance liquid chromatography (except for samples obtained on day 2) and fluorescence polarization immunoassay. Throughout the study period, the concentration of cyclosporine remaining in the paste was > 90% of the initial concentration according to both assay methods. Cyclosporine 9.6 mg/g in a paste compounded extemporaneously from cyclosporine oral solution and an adhesive gel was stable for at least 31 days when stored in aluminum-lined ointment tubes at 37, 21, and 2 degrees C.

Automatic image segmentation by integrating color-edge extraction and seeded region growing.

We propose a new automatic image segmentation method. Color edges in an image are first obtained automatically by combining an improved isotropic edge detector and a fast entropic thresholding technique. After the obtained color edges have provided the major geometric structures in an image, the centroids between these adjacent edge regions are taken as the initial seeds for seeded region growing (SRG). These seeds are then replaced by the centroids of the generated homogeneous image regions by incorporating the required additional pixels step by step. Moreover, the results of color-edge extraction and SRG are integrated to provide homogeneous image regions with accurate and closed boundaries. We also discuss the application of our image segmentation method to automatic face detection. Furthermore, semantic human objects are generated by a seeded region aggregation procedure which takes the detected faces as object seeds.

Dental amalgam and human health.

The use of dental amalgam as a restorative material has long been a contentious issue because of its elemental mercury component. While microleakage of mercury from amalgam has been conclusively confirmed over the past 30 years intensive research has failed to identify deleterious health outcomes. Mercury, as with other metals entering the body tissues, appears to be tolerated at low levels. Nevertheless, a contrary opinion is held by some professional and lay groups who advocate a zero tolerance for inhaled or ingested elemental mercury. They identify dental amalgam as an aetiological factor for neurological conditions such as chronic fatigue syndrome, multiple sclerosis and Alzheimer's disease resulting from chronic mercury poisoning. Epidemiological and clinical evidence of widespread chronic mercury toxicity associated with a body burden of amalgam has consistently failed to be established even in populations with a high prevalence of dental amalgam restorations. On current evidence, international consensus heavily supports the statement that amalgam does not constitute a health risk to patients. However, exposure to volatile free mercury in dental clinics should be controlled to eliminate occupational risk. This paper provides a general review of the current situation and issues. It offers a consensus viewpoint for practitioners and lay people in reaching an informed decision on dental amalgam restorations.

The use of the Minimum Data Set. Home Care in a case management project in Hong Kong.

130 hospital-discharged elderly patients received our comprehensive assessment by using a Chinese Minimum Data Set-Home Care (MDS-HC). Our case manager developed and implemented care plans with reference to the computer-generated Clients Assessment Protocols. Results showed that the MDS-HC was sensitive to identify elderly persons' holistic needs, and helpful in formulating all-inclusive care plans.

FGF8b oncogene mediates proliferation and invasion of Epstein-Barr virus-associated nasopharyngeal carcinoma cells: implication for viral-mediated FGF8b upregulation.

The fibroblast growth factor 8b (FGF8b) oncogene is known to be primarily involved in the tumorigenesis and progression of hormone-related cancers. Its role in other epithelial cancers has not been investigated, except for esophageal cancer, in which FGF8b overexpression was mainly found in tumor biopsies of male patients. These observations were consistent with previous findings in these cancer types that the male sex-hormone androgen is responsible for FGF8b expression. Nasopharyngeal carcinoma (NPC) is a highly metastatic cancer of head and neck commonly found in Asia. It is etiologically associated with Epstein-Barr Virus (EBV) infection, inflammatory tumor microenvironment and relatively higher male predominance. Here, we reported for the first time that FGF8b is overexpressed in this EBV-associated non-hormone-related cancer of the head and neck, NPC. More importantly, overexpression of FGF8b mRNA and protein was detected in a large majority of NPC tumors from both male and female genders, in addition to multiple NPC cell lines. We hypothesized that FGF8b overexpression may contribute to NPC tumorigenesis. Using EBV-associated NPC cell lines, we demonstrated that specific knockdown of FGF8b by small interfering RNA inhibited cell proliferation, migration and invasion, whereas exogenous FGF8b stimulated these multiple phenotypes. Further mechanistic investigation revealed that in addition to NF-κB signaling (a major inflammatory signaling pathway known to be activated in NPC), an important EBV oncoprotein, the latent membrane protein 1 (LMP1), was found to be a direct inducer of FGF8b overexpression in NPC cells, whereas androgen (testosterone) has minimal effect on FGF8b expression in EBV-associated NPC cells. In summary, our study has identified LMP1 as the first viral oncogene capable of directly inducing FGF8b (an important cellular oncogene) expression in human cancer cells. This novel mechanism of viral-mediated FGF8 upregulation may implicate a new role of oncoviruses in human carcinogenesis.

Attenuation of lower-thoracic, lumbar, and sacral spinal cord motion: implications for imaging human spinal cord structure and function.

BACKGROUND AND PURPOSE: Recent literature indicates that cervical and upper-thoracic spinal cord motion adversely affect both structural and functional MR imaging (fMRI; particularly diffusion tensor imaging [DTI] and spinal fMRI), ultimately reducing the reliability of these methods for both research and clinical applications. In the present study, we investigated motion of the lower-thoracic, lumbar, and sacral cord segments to evaluate the incidence of similar motion-related confounds in these regions. MATERIALS AND METHODS: Recently developed methods, used previously for measuring cervical and upper-thoracic spinal cord motion, were employed in the present study to examine anteroposterior (A/P) and left-right (L/R) spinal cord motion in caudal regions. Segmented cinematic imaging was applied with a gradient-echo, turbo fast low-angle shot (turbo-FLASH) pulse sequence to acquire midline images of the cord at 24 cardiac phases throughout the lower-thoracic, lumbar, and sacral spinal cord regions. RESULTS: The magnitude of A/P motion was found to be largest in rostral cord regions, whereas in caudal regions (at the level of the T4/T5 vertebrae and below), peak cord motion was uniformly small (routinely < or =0.10 mm). L/R motion, however, was found to be minimal throughout the thoracic, lumbar, and sacral regions. CONCLUSION: Motion-related errors in spinal fMRI and DTI are expected to be significantly reduced throughout caudal regions of the spinal cord, thus yielding higher sensitivity and specificity compared with rostral regions. The paucity of such errors is expected to provide a means of observing the specific impact of motion (in rostral regions) and to enable the acquisition of uncorrupted DTI and fMRI data for studies of structure and function throughout lumbar and sacral regions.

Insulin resistance causes increased beta-cell mass but defective glucose-stimulated insulin secretion in a murine model of type 2 diabetes.

AIMS/HYPOTHESIS: Although insulin resistance induces compensatory increases in beta cell mass and function to maintain normoglycaemia, it is not clear whether insulin resistance can precipitate beta cell dysfunction and hyperglycaemia without a pre-existing beta cell susceptibility. We therefore examined the beta cell phenotype in the MKR mouse, a model in which expression of a dominant-negative IGF 1 receptor (IGF1R) in skeletal muscle leads to systemic insulin resistance and diabetes. MATERIALS AND METHODS: Circulating glucose, insulin and glucagon concentrations were measured. Insulin sensitivity, glucose tolerance and insulin release in vivo were assessed by i.p. insulin and glucose tolerance tests. Beta cell function was assessed via insulin secretion from isolated islets and the glucose gradient in the perfused pancreas. Beta cell morphology was examined via immunohistochemistry. MKR mice were fed a high-fat diet containing sucrose (HFSD) to test metabolic capacity and beta cell function. RESULTS: Insulin-resistant MKR mice developed hyperglycaemia and a loss of insulin responsiveness in vivo. Basal insulin secretion from the perfused pancreas was elevated, with no response to glucose. Despite the demand on insulin secretion, MKR mice had increased pancreatic insulin content and beta cell mass mediated through hyperplasia and hypertrophy. The HFSD worsened hyperglycaemia in MKR mice but, despite increased food intake in these mice, failed to induce the obesity observed in wild-type mice. CONCLUSIONS/INTERPRETATION: Our studies demonstrate that insulin resistance of sufficient severity can impair glucose-stimulated insulin secretion, thereby undermining beta cell compensation and leading to hyperglycaemia. Moreover, because insulin stores were intact, the secretory defects reflect an early stage of beta cell dysfunction.

Soil water content, soil strength and the growth of elm root suckers.

The elongation rate of root suckers of Dutch elm (Ulmus x hollandica Mill.) increased with increasing age of the sucker, soil water content and net growth pressure (the excess of turgor pressure over soil restraining pressure) and it decreased with increasing soil strength. The increase in the rate of sucker elongation with age was probably the result of a decrease in osmotic potential causing an increase in the turgor pressure. Increasing soil strength increased the rate of osmotic adjustment. The increase in the rate of sucker elongation with increasing soil water content was probably due to an increase in the water potential of the sucker and a decrease in soil strength associated with increasing soil water content.

Autogenous tooth transplantation: an alternative to dental implant placement?

Autogenous tooth transplantation, or autotransplantation, is the surgical movement of a tooth from one location in the mouth to another in the same individual. Once thought to be experimental, autotransplantation has achieved high success rates and is an excellent option for tooth replacement. Although the indications for autotransplantation are narrow, careful patient selection coupled with an appropriate technique can lead to exceptional esthetic and functional results. One advantage of this procedure is that placement of an implant-supported prosthesis or other form of prosthetic tooth replacement is not needed. This article highlights the indications for autogenous tooth transplantation using 3 case reports as examples. A review of the recommended surgical technique as well as success rates are also discussed.

Cerebrospinal fluid gamma-aminobutyric acid levels in dogs with chronic portosystemic encephalopathy.

Cerebrospinal fluid (CSF) gamma-aminobutyric acid (GABA) levels were measured in a dog model of spontaneous chronic portosystemic encephalopathy. Dogs with congenital portacaval shunts (intra- or extra-hepatic) develop neurological features of abnormal psychomotor behaviour and depressed consciousness that are consistent with the symptoms of chronic portosystemic encephalopathy in humans. In the five dogs studied, plasma ammonia was elevated, as was CSF tryptophan, both usual biochemical abnormalities in portosystemic encephalopathy. CSF levels of GABA in five dogs with portosystemic encephalopathy (100 +/- 13 pmol/ml) were not significantly different from those in five control dogs (96 +/- 14 pmol/ml). CSF levels of GABA were not altered after ammonia infusion. If enhanced GABA-ergic neurotransmission, due to influx of gut-derived GABA into the brain, is responsible for the pathophysiology of chronic portosystemic encephalopathy in this model, it is not reflected by increased levels of GABA in CSF.

Activity of dorsal raphe cells across the sleep-waking cycle and during cataplexy in narcoleptic dogs.

Cataplexy, a symptom associated with narcolepsy, represents a unique dissociation of behavioural states. During cataplectic attacks, awareness of the environment is maintained, as in waking, but muscle tone is lost, as in REM sleep. We have previously reported that, in the narcoleptic dog, noradrenergic cells of the locus coeruleus cease discharge during cataplexy. In the current study, we report on the activity of serotonergic cells of the dorsal raphe nucleus. The discharge patterns of serotonergic dorsal raphe cells across sleep-waking states did not differ from those of dorsal raphe and locus coeruleus cells recorded in normal rats, cats and monkeys, with tonic discharge in waking, reduced activity in non-REM sleep and cessation of activity in REM sleep. However, in contrast with locus coeruleus cells, dorsal raphe REM sleep-off neurones did not cease discharge during cataplexy. Instead, discharge continued at a level significantly higher than that seen in REM sleep and comparable to that seen in non-REM sleep. We also identified several cells in the dorsal raphe whose pattern of activity was the opposite of that of the presumed serotonergic cells. These cells were maximally active in REM sleep and minimally active in waking and increased activity during cataplexy. The difference between noradrenergic and serotonergic cell discharge profiles in cataplexy suggests different roles for these cell groups in the normal regulation of environmental awareness and muscle tone and in the pathophysiology of narcolepsy.

Vitamin supplementation of patients receiving haemodialysis.

In order to assess the necessity of vitamin supplementation for patients who are receiving haemodialysis, measurements of vitamin status were made, and both dietary and supplementary intakes were assessed, in 26 patients who were undergoing haemodialysis. Blood samples were collected from these patients before they underwent haemodialysis, after an overnight fast, for the measurement of plasma retinol, alpha-tocopherol and ascorbate levels. Serum and erythrocyte folate levels were measured also. Thiamin status was assessed by the effect of added thiamin pyrophosphate on erythrocyte transketolase activity and pyridoxine status was assessed by the effect of added pyridoxal-5'-phosphate on erythrocyte aminotransferase activity. All patients had elevated plasma retinol levels; 48% of patients had elevated plasma alpha-tocopherol levels; the plasma ascorbate level was low in 50% of patients but was elevated in 25% of patients; and plasma and erythrocyte folate levels were elevated in 76% and 91% of patients, respectively. Thiamin status was normal in all but one patient and the pyridoxine level appeared to be low in two other patients. Many patients had low dietary intakes of vitamin C, folate and vitamin B6. We conclude that supplements of vitamins A and E are not required and, when dietary intakes of water-soluble vitamins are marginal, these should be supplemented at a dose as near as possible to the recommended dietary intake.

Clinical and radiologic lacrimal testing in patients with epiphora.

OBJECTIVE: The purpose of the study is to assess the strengths and weaknesses of selected clinical and radiologic lacrimal tests in patients with epiphora. DESIGN: The study design was a prospective clinical trial. PARTICIPANTS: Fifteen patients with epiphora (N = 27 eyes) were studied. METHODS: All patients underwent Jones testing, the dye disappearance test, canalicular probing, lacrimal scintigraphy, and macrodacryocystography. MAIN OUTCOME MEASURES: The dye disappearance test was graded individually by three ophthalmologists. Lacrimal scintigraphy and macrodacryocystography were evaluated by a nuclear medicine specialist and a radiologist, respectively. A panel of three ophthalmologists evaluated the data using a scoring system that relied on the preponderance of evidence to arrive at a final assessment. RESULTS: When the Jones I test results were negative (dye recovered from the nose), the epiphora was always from hypersecretion. When the Jones I test results were positive (no dye recovered from the nose), obstruction was not always present. When the dye disappearance test results were strongly abnormal, obstruction was always present. In contrast, when the dye disappearance test results were normal, the lacrimal drainage system was not always patent. Canalicular probing was more reliable than scintigraphy in identifying canalicular obstruction. Marked stenosis of the sac or duct on dacryocystography essentially confirmed nasolacrimal outflow obstruction; however, with the authors' technique, a normal study was found in some patients with functional or partial obstruction. CONCLUSIONS: More than one lacrimal test may be required for a definitive diagnosis in patients with epiphora due to partial or functional nasolacrimal outflow obstruction.