A novel (6S)-4,6-dimethyldodeca-2E,4E-dienoyl ester of phomalactone and related alpha-pyrone esters from a Phomopsis sp. with cytokine production inhibitory activity

A series of novel 6-substituted 5,6-dihydro-5-hydroxy-alpha-pyrone esters, 1 approximately 3, isolated from fermentations of a Phomopsis sp. (Xenova culture collection no. X22502) have been identified as inhibitors of lipopolysaccharide (LPS)-induced cytokine production. These include the (6S)-4,6-dimethyldodecadien-2E,4E-dienoyl ester of phomalactone, 1, and two analogues bearing a prop-2E-enoic acid moiety at the 6-position of the alpha-pyrone ring. (6S)-4,6-Dimethyl-2E,4E-dienoic acid, 4, and a hydroxylated analogue, 5, were also isolated and characterised. The most potent cytokine production inhibitor was 1, which inhibited LPS-induced tumour necrosis factor alpha (TNFalpha) production by U937 cells and LPS-induced interleukin 1beta (IL-1beta) production by peripheral blood mononuclear cells (PBMC) with IC50 values of 80 nM and 190 nM respectively. The effect of 1 in PBMC was selective for IL-1beta relative to TNFalpha. The inhibition of IL-1beta production by 1 involved a post-translational mechanism of action at the level of IL-1beta secretion as demonstrated by the lack of an effect on cell-associated IL-1beta production. 1 showed no effect on the activity of caspase 1 in cytosolic extracts from the THP1 monocytic cell line.

Cellular immune responses are essential for the development of Helicobacter felis-associated gastric pathology

The bacteria Helicobacter pylori is a major human pathogen that infects over half of the world's population. Infection initiates a series of changes in the gastric mucosa, beginning with atrophic gastritis and leading in some patients to peptic ulcer disease, mucosa-associated lymphomas, and gastric adenocarcinoma. Although this cascade of events clearly occurs, little is known about the role of the host immune response in disease progression. We have utilized the C57BL/6 Helicobacter felis mouse model to critically analyze the role of the adaptive immune response in the development of Helicobacter-associated gastric pathology. Infection of B and T cell-deficient RAG-1-/- mice or T cell-deficient TCRbetadelta-/- mice with H. felis resulted in high levels of colonization, but no detectable gastric pathology. Conversely, infection of B cell-deficient microMT mice resulted in severe gastric alterations identical with those seen in immunocompetent C57BL/6-infected mice, including gastric mucosal hyperplasia and intestinal metaplasia. These results demonstrate that the host T cell response is a critical mediator of Helicobacter-associated gastric pathology, and that B cells and their secreted Abs are not the effectors of the immune-mediated gastric pathology seen after H. felis infection. These results indicate that in addition to specific Helicobacter virulence factors, the host immune response is an important determinant of Helicobacter-associated disease.

Clinical laboratory technician to clinical laboratory scientist articulation and distance learning

Laboratory workers and educators alike are challenged to support access to education that is current and provides opportunities for career advancement in the work place. The clinical laboratory science (CLS) program at the Medical College of Georgia in Augusta developed a clinical laboratory technician (CLT) to CLS articulation option, expanded it through distance learning, and integrated computer based learning technology into the educational process over a four year period to address technician needs for access to education. Both positive and negative outcomes were realized through these efforts. Twenty-seven students entered the pilot articulation program, graduated, and took a CLS certification examination. Measured in terms of CLS certification, promotions, pay raises, and career advancement, the program described was a success. However, major problems were encountered related to the use of unfamiliar communication technology; administration of the program at distance sites; communication between educational institutions, students, and employers; and competition with CLT programs for internship sites. These problems must be addressed in future efforts to provide a successful distance learning program. Effective methods for meeting educational needs and career ladder expectations of CLTs and their employers are important to the overall quality and appeal of the profession. Educational technology that includes computer-aided instruction, multimedia, and telecommunications can provide powerful tools for education in general and CLT articulation in particular. Careful preparation and vigilant attention to reliable delivery methods as well as students' progress and outcomes is critical for an efficient, economically feasible, and educationally sound program.

Magnesium reduces free radicals in an in vivo coronary occlusion-reperfusion model

OBJECTIVE

This study demonstrated that magnesium (Mg) reduces free radicals after a brief coronary occlusion-reperfusion sequence.

BACKGROUND

Magnesium has been shown to reduce infarct size in patients with acute myocardial infarction. We hypothesized that this action of Mg occurs through its action on free radicals.

METHODS

Eighteen mongrel dogs were studied (nine control, nine receiving Mg). Catheters were placed into the coronary sinus for continuous blood withdrawal. A Varian E-4 electron paramagnetic resonance spectrometer was used to monitor the ascorbate free radical (AFR) signal in the coronary sinus blood; AFR is a measure of total oxidative stress. Occlusion of the left anterior descending coronary artery for 20 min was followed by reperfusion. The study animals received 4 g Mg intravenously starting at 15 min of occlusion (5 min before reperfusion) and continuing during reperfusion.

RESULTS

Results are presented as percent change from baseline +/- SEM. Magnesium blunted the peak AFR increase: at 4 min of reperfusion there was a 4.7 +/- 3.3% increase in AFR signal in the dogs receiving Mg versus an 18.2 +/- 3.3% increase in the control animals (p < 0.05). Total radical flux was reduced during reperfusion by 53% in the Mg dogs compared with controls (p < 0.05).

CONCLUSIONS

Magnesium attenuates AFR increase after an occlusion-reperfusion sequence. To our knowledge this is the first in vivo real-time demonstration of Mg's impact on free radicals.

Autoreactivity of T cells from nonobese diabetic mice: an I-Ag7-dependent reaction

Mice bearing the I-Ag7 class II major histocompatibility complex molecules contain a high number of spontaneous autoreactive T cells, as estimated by limiting-dilution assays. We found this autoreactivity in various strains that bear the I-Ag7 molecule, such as the nonobese diabetic (NOD) mouse strain, which spontaneously develops autoimmune diabetes. However, NOD mice strains that do not express the I-Ag7 molecule, but instead express I-Ab, do not have a high incidence of autoreactive T cells. About 15% of the autoreactive T cells also recognize the I-Ag7 molecule expressed in the T2 line, which is defective in the processing of protein antigens. We interpret this to mean that some of the T cells may interact with class II molecules that are either devoid of peptides or contain a limited peptide content. We also find a high component of autoreactivity among antigen-specific T cell clones. These T cell clones proliferate specifically to protein antigens but also have a high level of reactivity to antigen-presenting cells not pulsed with antigen. Thus, the library of T cell receptors in NOD mice is skewed to autoreactivity, which we speculate is based on the weak peptide-binding properties of I-Ag7 molecules.

Blood donor rejection rate: HemoCue hemoglobin analyzer vs. microhematocrit

This study compared 2 different methodologies: hemoglobin by the HemoCue instrument and hematocrit by the microhematocrit method, to determine if there were any significant difference in the values that could affect donor rejection rates. Literature from the 1960s to 1990s reveals a variety of methods for hemoglobin and hematocrit determinations as well as discussions on fingerstick versus earlobe capillary samples. The HemoCue hemoglobin analyzer is a relatively new technology that tests capillary specimens. The copper sulfate method, although the method of choice for measuring prospective donor hemoglobin levels for many years, was not a part of the study. The microhematocrit method has historically been used as the method for measuring hematocrit alone or as a secondary procedure when donors failed the copper sulfate screening test.

Using laboratory-based surveillance data for prevention: an algorithm for detecting Salmonella outbreaks

By applying cumulative sums (CUSUM), a quality control method commonly used in manufacturing, we constructed a process for detecting unusual clusters among reported laboratory isolates of disease-causing organisms. We developed a computer algorithm based on minimal adjustments to the CUSUM method, which cumulates sums of the differences between frequencies of isolates and their expected means; we used the algorithm to identify outbreaks of Salmonella Enteritidis isolates reported in 1993. By comparing these detected outbreaks with known reported outbreaks, we estimated the sensitivity, specificity, and false-positive rate of the method. Sensitivity by state in which the outbreak was reported was 0%(0/1) to 100%. Specificity was 64% to 100%, and the false-positive rate was 0 to 1.

Affinity maturation without germinal centres in lymphotoxin-alpha-deficient mice

Affinity maturation by somatic hypermutation is thought to occur within germinal centres. Mice deficient in lymphotoxin-alpha (LT alpha-/- mice) have no lymph nodes or Peyer's patches, and fail to form germinal centres in the spleen. We tested whether germinal centres are essential for maturation of antibody responses to T-cell-dependent antigens. LT alpha-/- mice immunized with low doses of (4-hydroxy-3-nitrophenyl)acetyl-ovalbumin (NP-OVA) showed dramatically impaired production of high-affinity anti-NP IgG1. However, LT alpha-/- mice immunized with high doses of NP-OVA, even though they failed to produce germinal centres, manifested a high-affinity anti-NP IgG1 response similar to wild-type mice. Furthermore, when LT alpha-/- mice were multiply immunized with high doses of NP-OVA, the predominantly expressed anti-NP VH gene segment VH186.2 showed somatic mutations typical of affinity maturation. Thus, B-cell memory and affinity maturation are not absolutely dependent on the presence of germinal centres.

Prostaglandin fever in rats throughout the estrous cycle late pregnancy and post parturition

We have examined the influence of natural variations in endocrine status on the ability to generate a prostaglandin-induced fever in virgin female, pregnant and lactating rats and compared responses to those in male rats. Endocrine status of virgin female rats was assessed from examination of vaginal smears and time of parturition noted to enable accurate dating of pre- and postparturient fevers. Unanesthetized rats, previously prepared with intraventricular guide cannulas and intraperitoneal telemetry thermistors, were given intraventricular injections of prostaglandin E1 (2-100 ng/5 microliters) and temperatures monitored for 3 h after injection. Virgin females developed significantly larger fevers than did males at higher doses. There were no significant alterations in either fever height or duration as a function of the phase of the reproductive cycle in the females. Both pregnant and postparturient rats within the several days around birth displayed significantly lower fevers than did virgin females, but there was no further reduction in the immediate periparturient period. These data indicate that there are sex-, and possibly hormone-dependent differences in the central mechanisms involved in fever generation and antipyresis.

Fever in pregnant, parturient, and lactating rats

Conscious virgin, pregnant, or lactating rats were given intravenous Escherichia coli endotoxin while their temperatures were monitored telemetrically. Virgin females responded to 10-50 micrograms/kg endotoxin with a slight hypothermia, followed by a fever of nearly 2 degrees C magnitude. In pregnant rats given 25 micrograms/kg of the endotoxin, fevers were reduced between 96 h before and 24 h after parturition compared with those seen in virgins or in lactating rats > 24 h postpartum. In the 24-h period before expected time of parturition, no rat developed a fever and the majority of animals became hypothermic; furthermore, in 80% of such animals given 25 micrograms/kg endotoxin, the hypothermia was accompanied by death within 3-15 h. Some mortality and hypothermia were also seen up to 48 h before birth and up to 24 h after birth. No mortality was observed in virgin, pregnant, or lactating rats outside of this time period. We conclude that, around the time of delivery, there is a suppression of fever in the rat and occasional toxic responses to endotoxin.

Case report: a pregnant woman with immune thrombocytopenic purpura and unusual red cell antibodies

Maternal immune thrombocytopenic purpura (ITP) may lead to fetal platelet destruction. This process is mediated by IgG platelet autoantibodies that cross the placenta. In this case, not only were platelet autoantibodies present, but red cell alloantibodies anti-E, anti-M, and anti-He were also present. Anti-E, present as an IgG antibody, crossed the placenta, but did not cause clinical problems in the E+ newborn, other than possible hyperbilirubinemia that was treated by phototherapy.

CNS-directed case management. Cost and quality in harmony

Preserving the integrity of high quality care in a financially restricted environment is the primary challenge facing healthcare providers. The critical question is which delivery system will use limited resources most efficiently without jeopardizing quality of care? Case management has been identified as a solution that offers the most promise. The case management model at Sioux Valley Hospital was developed to deal proactively with resource-intensive patients with chronic illnesses who have frequent admissions and who create financial risk for the hospital. The authors describe the fiscal and clinical outcomes of these select patients.

Pulmonary sequestration: 17-year experience at UCLA

Pulmonary sequestration is a complex anomaly involving the pulmonary parenchyma and its vascularity. From 1975 to 1992, 10 cases have been treated at the UCLA Medical Center. The ages of the seven females and three males were bimodal, the median age of the seven children was 29 days (range 1 day-6 years); it was 32 years (range 28-39) for the three adults. One child was delivered by cesarean section for fetal distress and another was born at 29 weeks gestation. Symptoms included: recurrent pneumonia (5), respiratory distress (5), hemoptysis (2), stridor (1), and pleuritis (1). Chest radiographs were consistent with sequestration in seven patients and diaphragmatic hernia in another, but incorrectly diagnosed one diaphragmatic eventration and one pulmonary varix. Computed tomographs suggested sequestration in five patients, but mistakenly interpreted a pulmonary varix in one case. Angiography, ultrasonography, and magnetic resonance imaging were infrequent investigative studies and yielded variable results. All patients underwent thoracotomy and lobectomy without morbidity or mortality. Five had intralobar and five had extralobar sequestration. All adults had intralobar sequestration. Two had aberrant subdiaphragmatic arterial vessels. Eight had vessels originating from the descending thoracic aorta. Nine patients are asymptomatic at six months to 10 years follow up. The 29-week-old premature infant died 30 days postoperatively due to necrotizing enterocolitis. Pulmonary sequestration remains an uncommon entity. The radiologic investigations that provide the most information are the chest radiography and computed tomography. Definitive diagnosis is made at thoracotomy. Pulmonary sequestrations are resected with excellent results by the trained thoracic surgeon who is aware of the unusual vascular connections.

Perfluorochemical reperfusion yields improved myocardial recovery after global ischemia

Reperfusion injury remains a limiting factor in extending ischemic storage time for human heart transplantation. In this study, initial myocardial reperfusion with an oxygenated perfluorochemical (Fluosol) was investigated as a means of limiting such injury. Neonatal piglet hearts were arrested with crystalloid cardioplegia, excised, and stored for 12 hours in saline solution at 0 degrees C. Initial reperfusion (10 minutes) was either with whole blood (n = 6), unmodified perfluorochemical (n = 8), or aspartate/glutamate-enriched perfluorochemical cardioplegia (n = 6), and was followed by an additional 40 minutes of whole blood perfusion. Functional evaluation was then completed, and left ventricular biopsy specimens were taken. A control group (n = 7) was evaluated without an intervening period of ischemia. At a left ventricular end-diastolic pressure of 9 mm Hg, hearts stored in whole blood cardioplegia developed a left-ventricular stroke work index of 3.8 +/- 2.3 x 10(3) erg/g (mean +/- standard error of the mean). Under the same conditions, perfluorochemical-reperfused hearts achieved a stroke work index of 14.6 +/- 1.3 x 10(3) erg/g, significantly greater than that of the whole blood group (p < 0.001). Stroke work index for hearts reperfused with aspartate/glutamate-enriched perfluorochemical cardioplegia was 19.8 +/- 1.6 x 10(3) erg/g, significantly increased over that of the nonenriched perfluorochemical group (p < 0.01) and not different from values obtained in controls (19.2 +/- 0.8 x 10(3) erg/g).(ABSTRACT TRUNCATED AT 250 WORDS)

A method for continuous blood sampling during cold water immersion

A technique, consisting of a pre-calibrated, catheter-peristaltic pump combination, for continuous blood sampling was tested using six volunteers during a 20 min immersion in cold water at 14.7 +/- 0.9 degrees C. The device offered the advantage of continued collection of blood samples from an antecubital vein during the experiment with little discomfort for the subjects and in sufficient volume for assay of plasma constituents eg. catecholamines.

Fluosol cardioplegia results in complete functional recovery: a comparison with blood cardioplegia

Blood cardioplegia is considered by many to be the preferred solution for myocardial protection. Proposed benefits include the ability to deliver oxygen and the ability to maintain metabolic substrate stores. However, the decreased capacity of blood to release oxygen at hypothermic conditions as well as the presence of deleterious leukocytes, platelets, and complement may limit complete functional recovery. Fluosol is an asanguineous solution with the ability to bind and release oxygen linearly at low temperatures. Neonatal piglet hearts (24 to 48 hours old) were excised and supported on an isolated, blood-perfused working heart model. After baseline stroke-work index was determined, hearts were arrested with either normocalcemic blood cardioplegia (group 1, n = 8) or normocalcemic Fluosol cardioplegia (group 2, n = 8). Cold cardioplegia was administered at 45 mm Hg every 20 minutes for 2 hours. Hearts were then reperfused with whole blood. Functional recovery, expressed as percent of control stroke-work index, was determined 60 minutes after reperfusion at left atrial pressures of 3, 6, 9, and 12 mm Hg. Functional recovery at 60 minutes was similar between group 1 (95%, 93%, 93%, 88%) and group 2 (100%, 94%, 94%, 95%) at left atrial pressures of 3, 6, 9, and 12 mm Hg, respectively. Mean lactate consumption 5 minutes after reperfusion was significantly greater (p = 0.0001) in group 1 (31.8 +/- 6.3 micrograms.min-1 x g-1) than in group 2 (-0.59 +/- 0.1 microgram.min-1 x g-1), indicating superior metabolic recovery in the blood cardioplegia hearts. Edema formation, as determined both by water content (group 1, 81.10%; group 2, 81.63%) and by electron microscopy, was not significantly different between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

PHLIS: an electronic system for reporting public health data from remote sites

Disease surveillance conducted by the Centers for Disease Control (CDC) in conjunction with state health departments provides databases of information to public health workers. These databases' utility is limited by the lag time from occurrence of disease events until records are available for analysis. We developed the Public Health Laboratory Information System (PHLIS), a PC-based electronic reporting system for entering, editing, and analyzing data locally and for transmitting data electronically to other state or federal offices. Advantages of PHLIS include reduction in paper handling, decrease in lag time between disease incident and availability of information for analysis, ability to rapidly examine data for clusters of disease, downloadable summary tables, data editing at site of input, data analysis capability, increased interaction among participants, and current data for responses to inquiries. PHLIS is available without cost and is transportable to other agencies, states, or countries.

Perfluorochemical reperfusion limits myocardial reperfusion injury after prolonged hypothermic global ischemia

The ability of an oxygenated perfluorochemical (Fluosol) to limit myocardial reperfusion injury following global hypothermic ischemic insult was investigated. Neonatal piglet hearts were arrested with cold crystalloid cardioplegia and stored for 12 hours in 2 degrees C saline. Reperfusion was carried out using an isolated, blood-perfused, working heart preparation. Hearts were initially reperfused (10 minutes) with either whole blood (WB, n = 6), unmodified perfluorochemical (PFC, n = 8), or aspartate/glutamate-enriched perfluorochemical cardioplegia (PFC+, n = 6), prior to institution of whole blood perfusion, functional evaluation and left ventricular biopsy. A control group (C, n = 7) was evaluated without an intervening period of ischemia. At a left ventricular diastolic pressure of 9 mm Hg WB hearts developed a left-ventricular stroke work index (SWI) of 3.8 +/- 2.3 x 10(3) erg/g (mean +/- standard error of the mean). Under similar conditions, PFC-reperfused hearts achieved a SWI of 14.6 +/- 1.3 x 10(3), significantly greater than that of WB (p less than 0.001). SWI for PFC+ hearts was 19.8 +/- 1.6 x 10(3), significantly increased over that of PFC (p less than 0.01), and not different from values obtained for C (19.2 +/- 0.8 x 10(3)). In addition, PFC-reperfused hearts demonstrated superior maintenance (p less than 0.05) of ATP (2.08 +/- 0.16 umole/g), compared to WB (1.50 +/- 0.19), while preservation of ATP in PFC+ hearts (2.99 +/- 0.12), was significantly increased over that of PFC (p less than 0.001), and not significantly different from that for C (2.68 +/- 0.17).(ABSTRACT TRUNCATED AT 250 WORDS)

Doctors and managers in Yorkshire--a meeting of minds

Describes the need to improve communication between doctors and managers in the NHS, to enable them to work together. Describes an approach to management development based on research findings. Those involved include a group of associates who contribute to management development programmes and initiatives for doctors and managers within Yorkshire.

Immunocytochemical double labeling of glial fibrillary acidic protein and transferrin permits the identification of astrocytes and oligodendrocytes in the rat brain

Sequential immunocytochemical double labeling of glial fibrillary acidic protein (GFAP) and transferrin (Tf) was used for the simultaneous identification of astrocytes and oligodendrocytes in paraffin-embedded sections of the rat brain. Paraformaldehyde or formalin-alcohol-acetic acid fixation followed by protease treatment of paraffin-embedded sections provided the most satisfactory double-labeling. The results demonstrated GFAP-positive astrocytes and Tf-positive oligodendrocytes as two subpopulations of glia with no overlap. Our results suggest that, with some exceptions, immunocytochemical double labeling of GFAP and Tf has a potential application for the simultaneous identification of astrocytes and oligodendrocytes in the rat brain.

Depletion of brain alpha-MSH alters prostaglandin and interleukin fever in rats

Alpha-melanocyte stimulating hormone (alpha-MSH), a putative endogenous antipyretic agent, is synthesized largely within neurons in the arcuate nucleus. To test the hypothesis that destruction of this area would increase the febrile response, male Wistar rats, treated as neonates with intraperitoneal injections of monosodium glutamate (MSG) or saline, were given intracerebroventricular (i.c.v.) injections of prostaglandin E1 (20 ng; 200 ng) or purified interleukin-1 (20 U) and body temperature was monitored. The fevers displayed by the MSG-treated animals were significantly greater (P less than 0.05) than those of the controls for the lower dose of PGE1 at 10-30 min and for IL-1 at 3-6 h after the injections. MSG-treated rats showed significant reduction (P less than 0.01) in alpha-MSH content of the medial basal hypothalamus and lateral septum when compared to saline controls. Body temperature response of non-febrile animals to high ambient temperature was not affected by the MSG treatment. These data support the hypothesis that alpha-MSH is an endogenous antipyretic in the rat.

Influenza outbreaks in nursing homes: how effective is influenza vaccine in the institutionalized elderly?

During the 1984-1985 influenza season, outbreaks of influenza A (H3N2) occurred in three Connecticut nursing homes. Influenza vaccination rates were 67% (96 out of 144), 35% (30 out of 85) and 69% (332 out of 483), respectively. The relative risk of illness for vaccinated compared to unvaccinated residents was 1.8 (95% confidence interval, 0.6, 5.9), 1.6 (95% confidence interval, 0.8, 3.0) and 1.1 (95% confidence interval, 0.8, 1.7) for each of the three nursing homes, respectively. In the third outbreak, 22 vaccinated residents without clinical illness had a geometric mean titer of hemagglutination-inhibition (HI) antibody of 20. Although low, this titer was significantly higher than that of nine unvaccinated residents without clinical illness (12, p less than .05); only three (14%) vaccinated residents had HI titers of greater than or equal to 40. These results suggest that levels of HI antibody in vaccinated residents were not protective at the time of the third outbreak, four to five months after vaccination. In general, the study of vaccine effectiveness in nursing homes is limited by sample size and statistical power. Despite these limits, the retrospective investigation of influenza outbreaks in nursing homes is often the only practical way to evaluate influenza vaccine effectiveness in the elderly on a yearly basis.