Myelodysplastic syndrome and immunotherapy novel to next in-line treatments

Patients with Myelodysplastic syndromes (MDS) have few therapy options for sustainable responses in the frontline setting, and even less after hypomethylating agent (HMA) failure in relapsed and refractory setting. The only potential cure is an allogeneic hematopoietic stem cell transplant which is an unrealistic option for the majority of MDS patients. Immunotherapy with checkpoint inhibition, CAR-T cells, and vaccine therapy few have shown promise in a variety cancer and have now been tested in patients with MDS. Most trials have focused on AML patients and included small numbers of MDS patients. Until now, a dedicated review of immunotherapy outcomes in MDS patients has been lacking. Thus, herein we review outcomes of MDS patients after immunotherapies on a variety of clinical trials reported to date.

Inpatient burden of gastric cancer in the United States

Background

Gastric cancer is associated with significant morbidity and mortality. Over one-half of patients have advanced disease at the time of presentation, leading to a significant burden on the healthcare system. Limited epidemiological data exists on national inpatient hospitalization trends. The aim of this study is to determine the inpatient burden of gastric cancer in the United States.

Methods

We analyzed the Nationwide Inpatient Sample (NIS) database for all subjects with the diagnosis of malignant neoplasm of the stomach (ICD-9 code 151.x) as primary diagnosis during the period from 2001-2011. NIS is the largest all-payer inpatient care database in the U.S. Statistical significance of variation in the number of hospitalizations, patient demographics, and comorbidity measures was determined using Cochran-Armitage trend test.

Results

From 2001 to 2011, the number of hospitalizations with the diagnosis of malignant neoplasm of the stomach ranged between 22,430 and 25,371, however, the trend was not significant. Men were always more affected than women with no significant change in overall proportion (P<0.0001). Overall, in-hospital mortality decreased from 11.19% in 2001 to 6.47% in 2011 (P<0.0001). However, average cost of care per hospitalization increased from $21,710 in 2001 to $24,706 in 2011 (adjusted for inflation, P<0.0001).

Conclusions

The total number of hospitalizations remained relatively stable throughout the study period with higher proportion of men affected every year. Although in-hospital mortality in patients with the diagnosis of gastric cancer decreased over the study period, there was a significant rise in the cost of care.

A 54-year-old Woman with Myelofibrosis and Massive Hemothorax Due to Primary Extramedullary Hematopoiesis of the Pleura

Extramedullary hematopoiesis, which represents ectopic blood cell production, is usually an incidental finding accompanying hematologic pathology. The liver and spleen are the most common sites of extramedullary hematopoiesis, but thoracic involvement is likewise observed. Pleural effusions in the setting of intrathoracic extramedullary hematopoiesis have been attributed to mechanical interactions between the pleural surface and neighboring paravertebral masses consisting of hematopoietic tissue. Rupture of these highly vascularized lesions into the adjacent pleural space has been the putative mechanism in cases complicated by hemothorax. Histologically proven instances of islets of extramedullary hematopoiesis occurring on the pleural surface itself are exceedingly rare. Our case of a patient with myelofibrosis and massive pleural effusion is only the third such example described in the literature and the second to result in a confirmed hemothorax requiring surgery. As expected, technetium-99m sulfur (Tc-99m sulfur) colloid scanning accurately localized sites of extramedullary hematopoiesis in our patient, and there was a salutary response to radiation therapy.

SRSF2 mutations in myelodysplasia/myeloproliferative neoplasms

Recurrent gene mutations have been described with varying frequencies in myelodysplasia (MDS) /myeloproliferative neoplasm (MPN) overlap syndromes (MMOS). Recent work has placed significant focus on understanding the role of gene lesions involving the spliceosomal machinery in leukemogeneis. SRSF2 is a gene encoding critical spliceosomal proteins. SRSF2 mutations appear to play an important role in pathogenesis of MMOS, particularly in chronic myelomonocytic leukemia. Inhibition of splicing may be a new therapeutic approach. E7107, a spliceosome inhibitor, has been shown to differentially inhibit splicing more in SRSF2-mutant cells leading to decreased leukemia burden in mice. H3B-8800 is a small molecule modulator of spliceosome complex and has been shown to lower leukemia burden in SRSF2-P95H mutant mice. This review focuses on the incidence of mutant SRSF2 across various MMOS as well as recent clinical development of spliceosome inhibitors.

Percutaneous pleural drainage in patients taking clopidogrel: real danger or phantom fear?

Despite being categorized as a procedure associated with a low risk of iatrogenic hemorrhage, percutaneous pleural drainage in patients taking the ubiquitous antiplatelet agent clopidogrel is still commonly perceived as a risky proposition. There is mounting evidence, however, in support of the safety of percutaneous needle procedures in persons receiving this medication. Establishing that these pleural interventions can be performed safely without clopidogrel interruption would be of great clinical significance, especially in those taking it for recent cardiac stenting and therefore in danger of stent thrombosis should antiplatelet therapy (APT) be withheld. The purpose of the present review is to summarize the available data from published studies and series of thoracentesis and chest tube insertion in patients exposed to clopidogrel. Also incorporated into this review are relevant investigations from the thoracic surgery and interventional radiology experience, which contribute indirect evidence and help shape the context for interpreting the safety data reported in the pleural literature. At the end, an attempt is made to synthesize the current knowledge on this topic into conclusions for guiding practice.

SETBP1 mutations as a biomarker for myelodysplasia /myeloproliferative neoplasm overlap syndrome

Myelodysplasia (MDS) /myeloproliferative neoplasm (MPN) overlap syndrome has been described since the 2001 WHO classification as disorders that have both proliferative and dysplastic changes simultaneously. Specific disorders include chronic myelomonocytic leukemia (CMML), juvenile myelomonocytic leukemia (JMML), BCR-ABL negative atypical chronic myeloid leukemia (aCML) and unclassifiable MDS/MPN (MPN/MDS-U). Recurrent gene mutations in these conditions have been described. Among them, SETBP1 mutations have been identified in up to 32% of aCML, 24% of JMML, 18% of CMML and 10% of MDS/MPN-U patients. The mutation hotspot lies in the amino acid residues 858–871 in the SETBP1 protein. SETBP1 mutations in MDS/MPN overlap syndrome is associated with accelerated transformation to leukemia and poor prognosis. In this review, we summarized the latest data on the role of SETBP1 mutations in the overlap syndrome. SETBP1 mutations may serve as a biomarker for the diagnosis and poor prognosis of the overlap syndrome.

Atypical hemolytic uremic syndrome in first trimester pregnancy successfully treated with eculizumab

BACKGROUND

Atypical hemolytic uremic syndrome is a rare disorder which is known to cause acute thrombotic microangiopathy during pregnancy with poor maternal and fetal outcomes. Atypical hemolytic uremic syndrome is caused mostly by dysregulation of alternative complement pathway secondary to genetic mutations. Most of the cases reported have been in the post-partum period. We report a rare case of a patient who presents with thrombotic microangiopathy in the first trimester of her eleventh pregnancy and was successfully treated with eculizumab.

CASE PRESENTATION

A 30-year-old woman presented at 10 weeks of gestation with hypertension, hemolytic anemia, thrombocytopenia, and acute kidney injury, consistent with thrombotic microangiopathy. She was managed initially with daily plasmapheresis. However, her kidney function did not recover, requiring hemodialysis. ADAMTS13 activity was later found to be within normal limit, hence diagnosis of atypical hemolytic uremic syndrome was strongly considered at that time and she was immediately treated with anti-C5 humanized monoclonal antibody (eculizumab). The patient responded well (resolution of thrombotic microangiopathy and recovery of renal function) to eculizumab, with continued remission after discharge and successfully delivered a healthy baby at term without any peripartum complications.

CONCLUSION

Early recognition of atypical hemolytic uremic syndrome is often difficult as several other conditions also manifest as thrombotic microangiopathy during pregnancy, causing delay in initiating appropriate treatment. Our case suggests that treatment of atypical hemolytic uremic syndrome in early trimester of pregnancy with eculizumab results in good outcome to mother and fetus.

Gestational diabetes alters the fetal heart rate variability during an oral glucose tolerance test: a fetal magnetocardiography study

OBJECTIVE

Gestational diabetes mellitus (GDM) potentially harms the child before birth. We previously found GDM to be associated with developmental changes in the central nervous system. We now hypothesise that GDM may also impact on the fetal autonomic nervous system under metabolic stress like an oral glucose tolerance test (OGTT).

DESIGN

We measured heart rate variability (HRV) of mothers and fetuses during a three-point OGTT using fetal magnetocardiography (fMCG).

SETTING

Measurements were performed in the fMEG Centre in Tübingen.

POPULATION

After exclusion of 23 participants, 13 pregnant women with GDM and 36 pregnant women with normal glucose tolerance were examined.

METHODS

All women underwent the same examination setting with OGTT during which fMCG was recorded three times.

MAIN OUTCOME MEASURE(S)

Parameters of heart rate variability were measured.

RESULTS

Compared with mothers with normal glucose regulation, mothers with GDM showed increased heart rate but no significant differences of maternal HRV. In contrast, HRV in fetuses of mothers with GDM differed from those in the metabolically healthy group regarding standard deviation normal to normal beat (SDNN) (P = 0.012), low-frequency band (P = 0.008) and high-frequency band (P = 0.031). These HRV parameters exhibit a decrease only in GDM fetuses during the second hour of the OGTT.

CONCLUSIONS

These results show an altered response of the fetal autonomic nervous system to metabolic stress in GDM-complicated pregnancies. Hence, disturbances in maternal glucose metabolism might not only impact on the central nervous system of the fetus but may also affect the fetal autonomic nervous system.

TWEETABLE ABSTRACT

Metabolic stress reveals a different response of fetal autonomic nervous system in GDM-complicated pregnancies.

Complete remission after single agent blinatumomab in a patient with pre-B acute lymphoid leukemia relapsed and refractory to three prior regimens: hyperCVAD, high dose cytarabine mitoxantrone and CLAG

Background

The current standard of care for relapsed and refractory acute lymphoblastic leukemia (ALL) is combination chemotherapy.

Case presentation

We report a case of highly refractory ALL who was treated with blinatumomab. The ALL in this patient relapsed within a month after completion of hyperCVAD regimen and was refractory to high dose mitoxantrone/cytarabine and CLAG regimens.

Conclusion

This highly refractory pre-B Ph⁻ ALL was induced to complete remission after one course of single agent blinatumomab.

Age-dependent association of serum prolactin with glycaemia and insulin sensitivity in humans

The dopamine agonist bromocriptine has been approved for the treatment of type 2 diabetes in the United States. Bromocriptine inhibits prolactin secretion, and patients with hyperprolactinaemia display impaired insulin sensitivity. We therefore hypothesized that low prolactin levels are associated with lower glycaemia and higher insulin sensitivity in healthy subjects. Prolactin levels were determined from fasting serum in participants without diabetes from the cross-sectional Tübingen family study for type 2 diabetes (m/f = 562/1,121, age = 40 ± 13 years, BMI = 30 ± 9 kg/m(2)). A 75 g oral glucose tolerance test was performed, and the area under the glucose curve (AUC(0-120)Glucose) and insulin sensitivity index were calculated. A subgroup (n = 494) underwent hyperinsulinaemic-euglycaemic clamp tests. Prolactin associated positively with insulin sensitivity (p = 0.001, adjusted for gender, age, and BMI). Age strongly interacted (p < 0.0001) with the effect of prolactin on insulin sensitivity, inverting the positive relationship to a negative one in younger participants. Glycated haemoglobin (HbA1c) and AUC(0-120)Glucose correlated negatively with prolactin, and an interaction with age was found as well. Higher prolactin levels are associated with improved insulin sensitivity and lower glucose in individuals without diabetes. This relationship turns to its opposite in younger persons. As prolactin is a proxy for the dopaminergic tone in the central nervous system, these associations may indicate an age-dependent influence of the brain on peripheral insulin sensitivity.

Insulin resistant phenotype of polycystic ovary syndrome does not seem to be caused by variation in FTO

Genetic variation in the FTO gene is associated with increased body weight and reduced insulin sensitivity. We investigated whether genetic variation in FTO is associated with polycystic ovary syndrome (PCOS), a condition also characterized by insulin resistance. Furthermore, we tested whether insulin resistance is specifically associated with genetic variation in FTO in women with PCOS. Sixty-two nondiabetic patients with PCOS defined by the Rotterdam criteria were compared to BMI and age-matched women. Each PCOS case was matched to 2 controls. All participants underwent an oral glucose tolerance test and were genotyped for the single nucleotide polymorphism rs8050136 in the FTO gene. There was no difference in the frequency of FTO genotypes between the PCOS and the non-PCOS groups. In non-PCOS participants, genetic variation in FTO is associated with insulin sensitivity (p=0.03). This association remained significant after adjustment for age and/or BMI (p<= 0.03). In subjects with PCOS, however, FTO did not associate with insulin sensitivity (p=0.67). Genetic variation in FTO does not have an impact on insulin sensitivity in women with PCOS and is therefore not involved in the pathogenesis of the insulin resistant phenotype seen in patients with PCOS.

Exercise-induced albuminuria is associated with perivascular renal sinus fat in individuals at increased risk of type 2 diabetes

AIMS/HYPOTHESIS

Microalbuminuria represents an established surrogate marker of early diabetic nephropathy and glomerular microangiopathy. Increasing evidence is emerging of a role of perivascular adipose tissue (PVAT) as an important link between obesity, insulin resistance and both macro- and microangiopathy. It is not known whether perivascular renal sinus fat (RSF) has an impact on microalbuminuria in the prediabetic stage. We investigated whether RSF quantified by MRI is associated with microalbuminuria before or after exercise.

METHODS

Non-diabetic individuals at increased risk of type 2 diabetes were recruited into the Tübingen Lifestyle Intervention Program (TULIP); 146 participants took part in the analysis. RSF was measured in axial MRI sections at the level of the renal artery. Urine was collected before and after exercise stress testing.

RESULTS

Participants (age 47 ± 12 years; mean ± SD) reached a mean exercise load of 176 ± 49 W, with a mean arterial peak pressure (MAPP) of 112 ± 14 mmHg. After adjusting for sex, age, visceral adipose tissue (VAT) and MAPP during exercise, RSF was significantly associated with postexercise albumin/creatinine ratio (ACR; p = 0.006). No association between RSF and baseline BP could be observed after adjusting for confounders (p = 0.26), and there was no association between RSF and baseline ACR either (p = 0.2).

CONCLUSIONS

RSF is associated with exercise-induced albuminuria independently of sex, age, VAT and MAPP in a non-diabetic cohort at diabetic risk. We conclude that PVAT in the renal sinus may play a role in the pathogenesis of microalbuminuria.

Nasal insulin changes peripheral insulin sensitivity simultaneously with altered activity in homeostatic and reward-related human brain regions

AIMS/HYPOTHESIS

Impaired insulin sensitivity is a major factor leading to type 2 diabetes. Animal studies suggest that the brain is involved in the regulation of insulin sensitivity. We investigated whether insulin action in the human brain regulates peripheral insulin sensitivity and examined which brain areas are involved.

METHODS

Insulin and placebo were given intranasally. Plasma glucose, insulin and C-peptide were measured in 103 participants at 0, 30 and 60 min. A subgroup (n = 12) was also studied with functional MRI, and blood sampling at 0, 30 and 120 min. For each time-point, the HOMA of insulin resistance (HOMA-IR) was calculated as an inverse estimate of peripheral insulin sensitivity.

RESULTS

Plasma insulin increased and subsequently decreased. This excursion was accompanied by slightly decreased plasma glucose, resulting in an initially increased HOMA-IR. At 1 h after insulin spray, the HOMA-IR subsequently decreased and remained lower up to 120 min. An increase in hypothalamic activity was observed, which correlated with the increased HOMA-IR at 30 min post-spray. Activity in the putamen, right insula and orbitofrontal cortex correlated with the decreased HOMA-IR at 120 min post-spray.

CONCLUSIONS/INTERPRETATION

Central insulin action in specific brain areas, including the hypothalamus, may time-dependently regulate peripheral insulin sensitivity. This introduces a potential novel mechanism for the regulation of peripheral insulin sensitivity and underlines the importance of cerebral insulin action for the whole organism.

Establishment and characterization of a canine soft tissue sarcoma cell line

Stringently controlled in vitro experiments are a necessary part of translational research. Cell lines are useful for exploring the underlying biology of cancer. Very few canine soft tissue sarcoma cell lines exist. This report describes the establishment of a new canine soft tissue sarcoma cell line (MBSa1) derived from a high-grade, metastatic neurofibrosarcoma. The primary tumor tissue was obtained from a 12-year-old neutered male German Shepherd Dog and was maintained in tissue culture for a minimum of 20 passages over 7 months. MBSa1 was injected into athymic mice to determine tumorigenicity. Five million cells were injected into the subcutis of the right flank of athymic nude mice. Nine of the 10 mice grew tumors 1 cm or larger within 8 weeks of cell injection. The large number of in vitro passages coupled with solid tumor formation in athymic nude mice demonstrates that MBSa1 has been immortalized and is tumorigenic.

Adipose tissue pathways involved in weight loss of cancer cachexia

Background:

The regulatory gene pathways that accompany loss of adipose tissue in cancer cachexia are unknown and were explored using pangenomic transcriptome profiling.

Methods:

Global gene expression profiles of abdominal subcutaneous adipose tissue were studied in gastrointestinal cancer patients with (n=13) or without (n=14) cachexia.

Results:

Cachexia was accompanied by preferential loss of adipose tissue and decreased fat cell volume, but not number. Adipose tissue pathways regulating energy turnover were upregulated, whereas genes in pathways related to cell and tissue structure (cellular adhesion, extracellular matrix and actin cytoskeleton) were downregulated in cachectic patients. Transcriptional response elements for hepatic nuclear factor-4 (HNF4) were overrepresented in the promoters of extracellular matrix and adhesion molecule genes, and adipose HNF4 mRNA was downregulated in cachexia.

Conclusions:

Cancer cachexia is characterised by preferential loss of adipose tissue; muscle mass is less affected. Loss of adipose tissue is secondary to a decrease in adipocyte lipid content and associates with changes in the expression of genes that regulate energy turnover, cytoskeleton and extracellular matrix, which suggest high tissue remodelling. Changes in gene expression in cachexia are reciprocal to those observed in obesity, suggesting that regulation of fat mass at least partly corresponds to two sides of the same coin.

Bcl-2 and Bax interactions in mitochondria probed with green fluorescent protein and fluorescence resonance energy transfer

It has been hypothesized that interaction of Bcl-2 and Bax may regulate apoptosis. The spatial and temporal interaction of Bcl-2 and Bax at the single cell level has not, however, been demonstrated. To achieve this goal, we have developed two-fusion FRET (fluorescence resonance energy transfer). Using green fluorescent protein (GFP)-Bax and blue fluorescent protein (BFP)-Bcl-2 fusion proteins coexpressed in the same cell, we demonstrate a direct interaction between Bcl-2 and Bax in individual mitochondria. Mitochondrially localized cytochrome c-GFP and BFP-Bcl-2 showed little or no FRET, while nuclear-localized GFP-human papillomavirus E6 and BFP-Bcl-2 did not interact when coexpressed in the same cell. These findings indicate that two-fusion FRET provides an opportunity to examine the interaction between two different proteins coexpressed in single intact mammalian cells.

Development of a stable single-vial formulation for a new technetium complex using bilayer lyophilization

The interaction between different components used in the preparation of a new radiodiagnostic agent, BMS-181321, was overcome by its lyophilization as a bilayered product. BMS-181321 is composed of a nitroimidazole ligand BMS-181032, that is complexed with technetium-99m just before it is used in radionuclide imaging studies. Stannous chloride is required to reduce technetium from the +7 to the +5 oxidation state before it can be complexed by the ligand. Because BMS-181032 is unstable in the presence of stannous chloride (when mixed in the liquid or solid state), the two components must be contained in separate vials. A bilayered lyophile was manufactured, containing the ligand and stannous chloride in separate layers in a single vial. The bilayered product was manufactured by first filling a solution of the ligand into a vial and freezing the solution. A solution containing stannous chloride was then filled into the same vial on top of the frozen layer of ligand, and this second layer was also frozen. The two frozen layers were then lyophilized to a dry solid cake. The resulting bilayered product showed stability comparable to that seen when the ligand and the reducing agent were contained in separate vials. The separation provided by the layering was sufficient to prevent any significant interaction between the reducing agent and the ligand.

Anatomy of the distal interphalangeal joint of the mature horse: relationships with navicular suspensory ligaments, sensory nerves and neurovascular bundle

The anatomy of the distal interphalangeal (DIP) joint in the adult horse is described in relationship to the suspensory ligaments of the navicular bone, the neurovascular bundle and the sensory nerves to these periarticular regions. Using polymer plastic injections, the synovial cavity of the DIP joint was observed to have a complex relationship to the proximal suspensory or collateral sesamoidean ligament (CSL) of the navicular bone with the cavity forming cranial and caudal compartments around the CSL abaxially. Sensory nerves, as identified by peptide immunocytochemistry and silver/gold chloride axonal impregnation, were present superficially throughout the dorsal and palmar parts of the CSL, the distal sesamoidean impar ligament and in the periarticular connective tissues. These anatomical observations provide support for the idea that a DIP joint injection of local anaesthetic cannot be considered to be selective for only the joint surfaces, but must be considered also to desensitise much of the navicular suspensory apparatus, navicular bone and proximal intramedullary portions of the distal phalanx. However, while a DIP joint injection is not selective for only the joint surfaces, we believe that it is useful in terms of the diagnosis of painful sensations arising from parts of the navicular bone, the suspensory apparatus and proximal positions of the distal phalanx. These anatomical findings are discussed in terms of the potential effects of local anaesthesia injected into the DIP joint with known clinical and necropsy observations of Dyson and Kidd (1993).

Nitroimidazoles for imaging hypoxic myocardium

A series of radiopharmaceuticals that incorporate nitroimidazole moieties have been synthesized to detect decreased local tissue pO2. In contrast to agents that localize in proportion to perfusion, these agents concentrate in hypoxic tissue. Myocardium with an intracellular pO2 < 3 mm Hg (about 25% of normal), which has lost its contractile ability but has maintained its ability to catabolize glucose, can be localized with this imaging technique. When a nitroimidazole enters a viable cell, the molecule undergoes a series of reactions: Initially, the molecule gains a single electron by an enzymatic process in the cytoplasm to form a potentially reactive species, then in the presence of adequate intracellular oxygen levels the molecule is reoxidized. These reactions are repeated until the intact molecule diffuses back out of the cell. In myocytes with reduced oxygen concentration, the reoxidation does not take place, the reactive species appears to undergo additional reduction reactions and remains in the cell. The association of the reduced nitroimidazole and other cellular elements is not irreversible, since these agents clear from hypoxic tissue with a half-life of 4 to 8 hours. In one of the first nitroimidazoles used for in vivo imaging, fluoromisonidazole was the radiopharmaceutical. Two major problems with fluoromisonidazole are its relatively low concentration within the lesion and the need to wait several hours to permit clearance of the agent from the normoxic background tissue (contrast between lesion and background typically < 2:1 at about 90 minutes after injection). Even with high resolution positron emission tomography imaging, this combination of circumstances makes successful evaluation of hypoxic lesions a challenge. The development of single photon agents with longer physical half-lives and comparable biologic properties offer a greater opportunity for successful imaging. In 1992 technetium 99m-labeled nitroimidazoles were described that had in vivo kinetics that were potentially suitable for detection of hypoxic myocardium. Laboratory studies showed preferential binding of these agents to hypoxic myocytes and isolated hearts in vitro and to ischemic myocardial tissue in laboratory animals. Patient studies are planned to determine whether the promise of these agents in laboratory studies can be realized in clinical practice.

Nitroimidazoles and imaging hypoxia

Decreased tissue oxygen tension is a component of many diseases. Although hypoxia can be secondary to a low inspired pO2 or a variety of lung disorders, the commonest cause is ischemia due to an oxygen demand greater than the local oxygen supply. In tumors, low tissue pO2 is often observed, most often due to a blood supply inadequate to meet the tumor's demands. Hypoxic tumor tissue is associated with increased resistance to therapy. In the heart tissue hypoxia is often observed in persistent low-flow states, such as hibernating myocardium. In patients with stroke, hypoxia has been associated with the penumbral region, where an intervention could preserve function. Despite the potential importance of oxygen levels in tissue, difficulty in making this measurement in vivo has limited its role in clinical decision making. A class of compounds known to undergo different intracellular metabolism depending on the availability of oxygen in tissue, the nitroimidazoles, have been advocated for imaging hypoxic tissue. When a nitroimidazole enters a viable cell the molecule undergoes a single electron reduction, to form a potentially reactive species. In the presence of normal oxygen levels the molecule is immediately reoxidized. This futile shuttling takes place for some time, before the molecule diffuses out of the cell. In hypoxic tissue the low oxygen concentration is not able to effectively compete to reoxidize the molecule and further reduction appears to take place, culminating in the association of the reduced nitroimidazole with various intracellular components. The association is not irreversible, since these agents clear from hypoxic tissue over time. Initial development of nitroimidazoles for in vivo imaging used radiohalogenated derivatives of misonidazole, such as fluoromisonidazole, some of which have recently been employed in patients. Two major problems with fluoromisonidazole are its relatively low concentration within the lesion and the need to wait several hours to permit clearance of the agent from the normoxic background tissue (contrast between lesion and background typically < 2:1 at about 90 min after injection). Even with high-resolution positron emission tomographic imaging, this combination of circumstances makes successful evaluation of hypoxic lesions a challenge.(ABSTRACT TRUNCATED AT 400 WORDS)

Sensory innervation of the navicular bone and bursa in the foal

The sensory innervation of the navicular bone (os sesamoideum distale) and its suspensory ligaments [ligamenta sesamoidea collateralia (CSL) and ligamentum sesamoideum distale impar or distal sesamoidean impar (DS-impar) ligament] and the navicular bursa (podotrochlearis) was examined in the neonatal foal using immunocytochemistry. With antisera raised to substance P (SP) and human calcitonin gene-related peptide (CGRP), immunoreactive nerves were demonstrated to innervate the CSL and navicular bursa. Within CSL, and SP- and CGRP-like nerves were present in the synovial lining of the navicular bursa, appearing to reach the surface lining. These nerves appeared to enter the CSL and navicular bursa via the abaxial regions of the foot. Both peptides were present in the deep digital flexor tendon (DDf) along the palmar border of the navicular bursa, as well as in the DS-impar ligament. More nerve fibres were present in the dorsal part of CSL bordering the distal interphalangeal joint than was observed palmarly in CSL along the navicular bursa. Both peptides were observed to innervate the cartilage canals within the navicular bone. In terms of relative densities of immunoreactive SP- and CGRP-like peptides, the CSL dorsally and the DS-impar ligament had the highest relative densities of nerve fibres followed by the navicular bone, the palmar aspect of CSL and the DDf tendon bordering the navicular bursa. These results are discussed in relationship to local anaesthetic injections into the navicular bursa.

A silver-impregnation and immunocytochemical study of innervation of the distal sesamoid bone and its suspensory ligaments in the horse

The innervation of the navicular bone (os sesamoideum distale) and its suspensory ligaments (ligamenta sesamoidea collateralia) (CSL) or proximal suspensory ligament and the ligamentum sesamoideum distale impar or the distal sesamoidean impar ligament (DS-impar ligament) was examined using combined anatomical techniques of silver impregnation and immunocytochemistry. Silver impregnation studies revealed an abundance of nerve fibres present in both the CSL and DS-impar ligament with the latter having relatively more nerve fibres. These silver-impregnated nerves coursed parallel to and were associated with the vasculature rather than appearing to innervate the vessels. Immunocytochemistry identified several sensory-related neuropeptides (calcitonin gene-related peptide (CGRP), substance P (SP) and neurokinin A (NKA)) in the nerves of the navicular bone and suspensory ligaments. More peptidergic nerves were evident within the synovial membrane and loose connective tissue in the dorsal part than in the palmar aspect of the CSL. In the CSL along the synovial membrane bordering the distal interphalangeal joint, the CGRP, SP and NKA were present in the nerves of vessels as well as the intimal layer of the distal interphalangeal joint. In the DS-impar ligament, there were many more nerves innervating vessels and the synovial membrane between the navicular bone and the third phalanx than were present in these structures in the CSL. Nerves with all 3 peptides entered the navicular bone via the proximal border and the distal groove to innervate the perichondrium, trabeculae and osteons. SP-like nerves also innervated the cortical bone underlying the articular cartilage. We suggest that these sensory nerve peptides contribute to the pathology of the navicular syndrome. The distribution of the nerves in the CSL and the DS-impar ligament could explain the clinical effects of local anaesthetics injected into the distal interphalangeal joint.

Membrane fatty acid and virulence changes in the viable but nonculturable state of Vibrio vulnificus

The nonculturable state of Vibrio vulnificus and, for comparison, that of Escherichia coli were studied in artificial-seawater microcosms at 5 degrees C. Total cell counts were monitored by acridine orange epifluorescence, metabolic activity by direct viable counts, and culturability by plate counts on selective and nonselective media. Whereas total counts remained constant, plate counts of V. vulnificus suggested nonculturability by day 24. In contrast, direct viable counts indicated significant cell viability throughout 32 days of incubation. As an indication of the metabolic changes that occurred as cells entered the state of nonrecoverability, membrane fatty acid analyses were performed. At the point of nonculturability of V. vulnificus, the major fatty acid species (C16 and C16:1) had decreased 57% from the T0 level, concomitant with the appearance of several short-chain acids. Although the bacteria were still recoverable, a similar trend was observed with E. coli. Electron microscopy of nonculturable V. vulnificus showed that the cells were rounded and reduced in size and contained fewer ribosomes. Mouse infectivity studies conducted with these cells suggested loss of virulence.

Production of extracellular enzymes and cytotoxicity by Vibrio vulnificus

Thirty-three strains of Vibrio vulnificus of clinical and environmental origin were examined for production of 12 extracellular enzymes of potential importance to the virulence of this bacterium. Strains of Vibrio vulnificus were consistent in their production of protease, mucinase, lipase, chondroitinase, hyaluronidase, DNase, sulfatase, and hemolysin. No differences between clinical and environmental isolates were noted. Although none of the enzymes appeared to correlate with the ability of these strains to produce lethality in mice, the production of hemolysin and of a protease with activity against native serum albumin may be significant in the pathogenesis of the potentially fatal infections produced by this organism. The production of several of these exoenzymes also appeared to correlate with pathogenicity in the seven other Vibrio species examined. Culture filtrates of all virulent strains of Vibrio vulnificus were cytotoxic for Chinese hamster ovary cells, whereas those of the strains of Vibrio parahaemolyticus and Vibrio alginolyticus examined lacked this activity.

Child-environment supervisors--a new strategy for prevention of childhood accidents

This paper is a provisional report from an ongoing field experiment in Uppsala, Sweden, with the aim to reduce the number of serious childhood accidents. Groups of parents have been systematically trained to function as child-environment supervisors. The experiences have been very positive so far. The child-environment supervisors have proved to possess good knowledge about how to prevent accidents. A large number of hazards have been detected and successfully eliminated. The groups are now taking an active part in the planning of new housing estates. The findings also indicate that the Child Health Organization should be able to play a more active role in the work of environmental improvement for the safety of children. A suggestion for a collective strategy for such activity has been worked out.