Inter-species hemorheologic differences in arterial and venous blood

BACKGROUND

Hemorheologic factors such as red blood cell (RBC) aggregation and deformability differ according to species. In many comparative hemorheologic studies, only venous blood samples have been used for measurements. There is little published information comparing arterial and venous blood differences between species. We compared hemorheologic factors in arterial and venous blood in rats, dogs and humans.

METHODS

Nineteen dogs and 12 rats were used. Human blood was obtained from 12 healthy volunteers. Blood gas analysis, hematocrit and elongation index which represents RBC deformability were measured in arterial and venous blood samples. The critical shear stress and aggregation index, both of which represent RBC aggregation, were also measured in arterial and venous blood.

RESULTS

There were no arterial or venous differences in hematocrit, critical shear stress, or elongation index in dogs. In rats, RBC aggregation was not measurable. The hematocrit and elongation index of arterial blood were significantly lower than those of venous blood in rats. There were no arterial or venous differences in hematocrit, aggregation index, or elongation index in humans.

CONCLUSION

Arterial and venous hemorheologic factors differed depending on the species. Further standardization is necessary for the measurement of hemorheologic variables.

Regeneration of ischemic heart using hyaluronic acid-based injectable hydrogel

An injectable hydrogel was applied to regenerate a myocardial infarction and functional recovery of the heart. A myocardial infarction was induced in rat by circumflex artery ligation. A hyaluronic acid-based hydrogel was injected into the epicardium of the infarcted area. Then, cardiac functions and regeneration of the myocardium in sham-operated (SHAM), myocardial infarction (MI), and gel-injected group (GEL) (n = 6) were evaluated 4 weeks after the injection. Measurements of the thickness of the wall showed that the thickness in the GEL group increased by up to 200% compared with that in the MI group (p < 0.001). The infarcted area of the left ventricular in the GEL group decreased by 53% compared with the MI group (p < 0.001). The number of arterioles and capillaries in the border zone of the GEL group increased by 152% and 148%, whereas the apoptotic index decreased by 42% (p < 0.05). Measurement of the heart functions, such as ejection fraction, arterial elastance (Ea), dP/dt max, and dP/dt min, indicated that the injection of a hydrogel significantly facilitated the functional recovery compared with the MI group. Because of its simplicity, easy applicability, and a great regenerating potential, this injectable hydrogel promises as a treatment for myocardial infarction.

Programmed death (PD)-1 molecule and its ligand PD-L1 distribution among memory CD4 and CD8 T cell subsets in human immunodeficiency virus-1-infected individuals

Human immunodeficiency virus (HIV)-1 causes T cell anergy and affects T cell maturation. Various mechanisms are responsible for impaired anti-HIV-1-specific responses: programmed death (PD)-1 molecule and its ligand PD-L1 are negative regulators of T cell activity and their expression is increased during HIV-1 infection. This study examines correlations between T cell maturation, expression of PD-1 and PD-L1, and the effects of their blockade. Peripheral blood mononuclear cells (PBMC) from 24 HIV-1(+) and 17 uninfected individuals were phenotyped for PD-1 and PD-L1 expression on CD4(+) and CD8(+) T cell subsets. The effect of PD-1 and PD-L1 blockade on proliferation and interferon (IFN)-gamma production was tested on eight HIV-1(+) patients. Naive (CCR7(+)CD45RA(+)) CD8(+) T cells were reduced in HIV-1 aviraemic (P = 0.0065) and viraemic patients (P = 0.0130); CD8 T effector memory subsets [CCR7(-)CD45RA(-)(T(EM))] were increased in HIV-1(+) aviraemic (P = 0.0122) and viraemic (P = 0.0023) individuals versus controls. PD-1 expression was increased in CD4 naive (P = 0.0496), central memory [CCR7(+)CD45RA(-) (T(CM)); P = 0.0116], T(EM) (P = 0.0037) and CD8 naive T cells (P = 0.0133) of aviraemic HIV-1(+) versus controls. PD-L1 was increased in CD4 T(EMRA) (CCR7(-)CD45RA(+), P = 0.0119), CD8 T(EM) (P = 0.0494) and CD8 T(EMRA) (P = 0.0282) of aviraemic HIV-1(+)versus controls. PD-1 blockade increased HIV-1-specific proliferative responses in one of eight patients, whereas PD-L1 blockade restored responses in four of eight patients, but did not increase IFN-gamma-production. Alteration of T cell subsets, accompanied by increased PD-1 and PD-L1 expression in HIV-1 infection contributes to anergy and impaired anti-HIV-1-specific responses which are not rescued when PD-1 is blocked, in contrast to when PD-L1 is blocked, due possibly to an ability to bind to receptors other than PD-1.

Shewanella fodinae sp. nov., isolated from a coal mine and from a marine lagoon

Strains JC15(T) and JC19 were isolated from samples collected from different locations in India, including a coal mine and a marine lagoon. Both strains were Gram-stain-negative rods, motile by means of a single polar flagellum, catalase- and oxidase-positive, and hydrolysed casein, produced H(2)S and showed beta-haemolysis. Strain JC15(T) grew optimally at pH 6 (range pH 5-8) while strain JC19 grew optimally at pH 7 (range pH 6-9) and both had a growth temperature optimum of 30-37 degrees C (range 22-40 degrees C). Both strains could grow chemo-organoheterotrophically and chemolithoautotrophically. Neither strain required NaCl for growth and both could tolerate up to 9 % (w/v) NaCl, with optimum growth at 5 % NaCl. Vitamin B(12) was required as a growth factor by both strains. The major fatty acids were iso-C(15 : 0), C(17 : 1)omega8c and iso-C(13 : 0) 3-OH. The DNA G+C contents of strains JC15(T) and JC19 were 53.6 and 54.3 mol%, respectively. A phylogenetic tree based on 16S rRNA gene sequence analysis showed that strains JC15(T) and JC19 were most closely related to Shewanella haliotis DW01(T) (approximately 94 % sequence similarity) and to other members of the genus Shewanella. Genomic relatedness (DNA-DNA hybridization) between strains JC15(T) and JC19 is 88 %. On the basis of phenotypic and molecular genetic evidence, strain JC15(T) represents a novel species of the genus Shewanella, for which the name Shewanella fodinae sp. nov. is proposed. The type strain is JC15(T) (=CCUG 57102(T) =NBRC 105216(T) =KCTC 22506(T)).

Development of a closed air loop electropneumatic actuator for driving a pneumatic blood pump

In this study, we developed a small pneumatic actuator that can be used as an extracorporeal biventricular assist device. It incorporated a bellows-transforming mechanism to generate blood-pumping pressure. The cylindrical unit is 88 +/- 0.1 mm high, has a diameter of 150 +/- 0.1 mm, and weighs 2.4 +/- 0.01 kg. In vitro, maximal outflow at the highest pumping rate (PR) exceeded 8 L/min when two 55 mL blood sacs were used under an afterload pressure of 100 mm Hg. At a pumping rate of 100 beats per minute (bpm), maximal hydraulic efficiency was 9.34% when the unit supported a single ventricle and 13.8% when it supported both ventricles. Moreover, pneumatic efficiencies of the actuator were 17.3% and 33.1% for LVAD and BVAD applications, respectively. The energy equivalent pressure was 62.78 approximately 208.10 mm Hg at a PR of 60 approximately 100 bpm, and the maximal value of dP/dt during systole was 1269 mm Hg/s at a PR of 60 bpm and 979 mm Hg/s at a PR of 100 bpm. When the unit was applied to 15 calves, it stably pumped 3 approximately 4 L/min of blood at 60 bpm, and no mechanical malfunction was experienced over 125 days of operation. We conclude that the presently developed pneumatic actuator can be utilized as an extracorporeal biventricular assist device.

Resection of a giant malignant mediastinal peripheral nerve sheath tumour under cardiopulmonary bypass

Malignant peripheral nerve sheath tumour (MPNST) is a rare occurrence in the mediastinum. It is biologically aggressive and is generally resistant to chemoradiation therapy. The mainstay of treatment is complete surgical resection. We report a large MPNST which invaded into the adjacent aortic wall in a 50-year-old man. Extensive resection, which included aortic reconstruction under cardiopulmonary bypass and deep hypothermic arrest, was necessary for a good long-term outcome.

Clinics in diagnostic imaging (126). Right atrial myxoma

A 47-year-old woman presented with dyspnoea on exertion for several weeks. Echocardiogram and multidetector computed tomography of the heart showed a right atrial mass typical of an atrial myxoma. This was confirmed on histology. The imaging features of atrial myxoma and other conditions presenting as a right-sided cardiac mass are discussed.

Antiviral activity of raoulic acid from Raoulia australis against Picornaviruses

RNA viruses are a major source of respiratory diseases worldwide. The lack of effective therapeutical treatment underlines the importance of research for new antiviral compounds. Raoulic acid is a principal ingredient of the plant Raoulia australis Hook. F. Antiviral assay using cytopathic effect (CPE) reduction method showed that raoulic acid possessed strong antiviral activity against human rhinovirus 2 (HRV2) with a 50% inhibition concentration (IC(50)) value of less than 0.1mug/ml, human rhinovirus 3 (HRV3) with a IC(50) value of 0.19 microg/ml, coxsackie B3 (CB3) virus with IC(50) values of 0.33 microg/ml, coxsackie B4 (CB4) virus with IC(50) values of 0.40 microg/ml, and enterovirus 71 (EV71) virus with IC(50) values of less than 0.1 microg/ml. However, the compound did not possess antiviral activity against influenza A (Flu A/PR, Flu A/WS, H1N1) and B viruses at four concentrations ranging from 0.1 to 100 microg/ml.

Occurrence of iatrogenic pneumothorax during laparoscopy-assisted distal gastrectomy: A case report

The occurrence of a pneumothorax during laparoscopy-assisted distal gastrectomy (LADG) is rare. A pneumothorax was developed during a LADG under general anesthesia in a 67-year-old woman with gastric cancer. About 140 minutes after CO2 insufflation, sudden hemodynamic collapse occurred. A defect was noted in the diaphragm. After immediate repair under laparoscopy, hemodynamic stability was achieved within several minutes. In the anesthetic management of a LADG, the anesthesia provider should be aware of the possible occurrence of a pneumothorax.

Anaesthetists' nightmare: masseter spasm after induction in an undiagnosed case of myotonia congenita

We report an undiagnosed case of myotonia congenita in a 24-year-old previously healthy primigravida, who developed life threatening masseter spasm following a standard dose of intravenous suxamethonium for induction of anaesthesia. Neither the patient nor the anaesthetist was aware of the diagnosis before this potentially lethal complication occurred.

Evaluation of Subchronic Inhalation Toxicity of Dimethyl Disulfide in Rats

This study was carried out to investigate the potential subchronic inhalation toxicity of dimethyl disulfide (DMDS) via whole-body exposure in F344 rats. Groups of 10 rats of each sex were exposed to DMDS vapor by whole-body exposure at concentrations of 0, 5, 25, or 125 ppm for 6 h/day, 5 days/wk for 13 wk. All the rats were sacrificed at the end of treatment period. During the test period, clinical signs, mortality, body weights, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross findings, organ weights, and histopathology were examined. At 25 ppm, a decrease in the body weight gain, food intake, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and blood urea nitrogen (BUN) was observed in the males, but not in the females. However, at 125 ppm, a decrease in the body weight gain, food intake, and thymus weight and an increase in the weights of adrenal glands were observed in both genders. Serum biochemical investigations revealed a decrease in the AST, ALT, BUN, creatine phosphokinase (CPK), and triglyceride levels and an increase in the glucose level. In contrast, no treatment-related effects were observed in the 5 ppm group. The toxic potency of DMDS was slightly higher in males than that in females. In these experimental conditions, the target organ was not determined in rats. The no-observed-adverse-effect concentration (NOAEC) was found to be 5 ppm, 6 h/day for male rats and 25 ppm, 6 h/day for female rats.

Low-grade dysplasia in Barrett's esophagus has a high risk of progression

BACKGROUND AND STUDY AIMS

Surveillance in Barrett's esophagus relies on the detection of dysplasia by histopathology. However, the natural history of this condition, particularly that of low-grade dysplasia (LGD) is poorly understood. This paper describes our experience of LGD over a period of 21 years.

PATIENTS AND METHODS

Between 1984 and January 1995, 357 patients with Barrett's esophagus without dysplasia were recruited for annual surveillance: 34 of these patients developed LGD during this period. This was a retrospective cohort study of this group in terms of survival and cancer outcomes >/= 8 years after the original diagnosis of LGD, comparing them with the patients who did not develop LGD over the same period, with a histopathological review of the original diagnoses of LGD. The outcomes of 356/357 (99.7 %) of the patients were established in December 2004.

RESULTS

After 8 years, high-grade dysplasia (HGD) or cancer had developed in 9/34 patients with LGD (27 %) and in 16/322 controls (5 %). Cox's proportional hazards model revealed that the time from the first diagnosis of Barrett's esophagus to the first "event" of either HGD, esophageal cancer, or death did not show a statistically significant difference between the two groups. A further analysis treating death as "loss to follow-up" showed a significantly increased risk for the LGD group to progress to HGD or cancer (hazard ratio 5.9 [95 % confidence interval 2.6 - 13.4], P< 0.001). The histopathology review demonstrated a fair level of agreement between pathologists, with a kappa value of 0.48.

CONCLUSIONS

Patients diagnosed with LGD during surveillance of Barrett's esophagus are at a considerably increased risk of progressing to develop esophageal cancer over an 8-year period but most deaths are not cancer-related.

Bilateral pneumothoraces as a complication of acupuncture

Pneumothorax developing secondary to acupuncture is rare. However, in an undiagnosed case, it may cause fatality. The real incidence of acupuncture-related pneumothorax is not known but is acknowledged to be underdiagnosed and under-reported. We describe pneumothorax occurring in a 52-year-old woman who developed bilateral pneumothoraces, with one side being a tension pneumothorax, immediately following acupuncture. The needle was inserted at a paravertebral point at the level of the third vertebral spinous process.

Hemodynamic energy generated by a combined centrifugal pump with an intra-aortic balloon pump

We examined the pulsatility generated by an intra-aortic balloon pump/centrifugal pump (IABP/CP) combination in terms of energy equivalent pressure (EEP) and surplus hemodynamic energy (SHE). In five cardiac-arrested pigs, the outflow cannula of the CP was inserted into the ascending aorta, the inflow cannula in the right atrium. A 30-ml IABP was subsequently placed in the descending aorta. Extracorporeal circulation was maintained for 30 minutes using a pump flow of 75 ml/kg per minute by CP alone or by IABP/CP with pressure and flow measured in the right internal carotid artery. The IABP/CP combination converted the flow to pulsatile and increased pulse pressure significantly from 9.1 +/- 1.3 mm Hg to 54.9 +/- 6.1 mm Hg (p = 0.012). It also significantly increased the percent change from mean arterial pressure to EEP from 0.2 +/- 0.3% to 23.3 +/- 6.1% (p = 0.012) and SHE from 133.2 +/- 234.5 erg/cm to 20,219.8 +/- 5842.7 erg/cm3 (p = 0.012). However, no statistical difference was observed between CP and IABP/CP in terms of mean carotid artery pressure (p = NS). In a cardiac-arrested animal model, pulsatility generated by a IABP/CP combination may be effective in terms of energy equivalent pressure and surplus hemodynamic energy.

Comparison of coronary artery blood flow and hemodynamic energy in a pulsatile pump versus a combined nonpulsatile pump and an intra-aortic balloon pump

We compared the coronary artery blood flow and hemodynamic energy between pulsatile extracorporeal life support (ECLS) and a centrifugal pump (CP)/intra-aortic balloon pump (IABP) combination in cardiac arrest. A total cardiopulmonary bypass circuit was constructed for six Yorkshire swine weighing 30 to 40 kg. The outflow cannula of the CP or a pulsatile ECLS (T-PLS) was inserted into the ascending aorta, and the inflow cannula of the CP or T-PLS was placed into the right atrium. A 30-ml IABP was subsequently placed in the descending aorta. Extracorporeal circulation was maintained for 30 minutes with a pump flow of 75 ml/kg per minute by a CP with an IABP or T-PLS. Pressure and flow were measured in the right internal carotid artery. The energy equivalent pressure (EEP) and surplus plus hemodynamic energy (SHE) were recorded. The left anterior descending coronary artery flow was measured with an ultrasonic coronary artery flow measurement system. The percent change of the mean arterial pressure to EEP was effective in both groups (23.3 +/- 6.1 in CP plus IABP vs. 19.8 +/- 6.2% in T-PLS, p = NS). The SHE was high enough in the CP/IABP and the T-PLS (20,219.8 +/- 5824.7 vs. 13,160.2 +/- 4028.2 erg/cm3, respectively, p = NS). The difference in the coronary artery flow was not statistically significant at 30 minutes after bypass was initiated (28.2 +/- 9.79 ml/min in CP plus IABP vs. 27.7 +/- 9.35 ml/min in T-PLS, p = NS).

Ventricular Assist Device Implantation Using a Right Thoracotomy

Most patients needing implantation of a ventricular assist device (VAD) require repeated sternotomy; some after cardiac surgery, and others later for heart transplantation. The purpose of this study was to establish the right thoracotomy technique as an alternative for VAD implantation to reduce repeated sternotomy-related morbidity and mortality. We performed a right thoracotomy in animals, preclinical cadaver fitting tests, and a clinical case. A total of 20 various animals underwent right thoracotomy for implantation of bi-VAD (BVAD, n = 17) and left VAD (LVAD, n = 3). The right chest cavity was entered through the fourth intercostal space with partial resection of the fifth rib. There was no procedure-related morbidity or mortality, except for one calf with right anterior leg paralysis. Preclinical fitting tests were performed on 7 human cadavers to observe the anatomical feasibility of BVAD cannulation from the right side of the heart. In humans, the ascending aorta, interatrial groove, right atrium, and main pulmonary artery were identified as optimal cannula insertion sites for BVAD implantation. A patient with cardiogenic shock underwent a right thoracotomy for implantation of an external LVAD. Cardiac function recovered after 3 weeks, and the device was successfully explanted through a repeat right thoracotomy. In conclusion, a right thoracotomy can be an alternative method to the standard median sternotomy for patients who need repeated sternotomy because of previous cardiac surgery, transplantation at a later date, or those with mediastinal infections.

Retinocollicular synaptogenesis and synaptic transmission during formation of the visual map in the superior colliculus of the wallaby (Macropus eugenii)

Spontaneous retinal activity has been implicated in the development of the topographic map in the superior colliculus (SC) but a direct demonstration that it reaches the colliculus is lacking. Here we investigate when the retinocollicular projection is capable of transmitting information from the retina in a marsupial mammal, the wallaby (Macropus eugenii). The projection develops postnatally, allowing in vivo analysis throughout development. Quantification of retinocollicular synaptogenesis has been combined with electrophysiology of the development and characteristics of retinocollicular transmission, including in vivo and in vitro recording in the same animals. Prior to postnatal day (P) 12-14 in vitro recording detected only presynaptic activity in retinal axons in the colliculus, in response to stimulation of the optic nerve. Postsynaptic responses, comprising both N-methyl-d-aspartate (NMDA) and non-NMDA responses, were first detected in vitro at P12-14 and retinal synapses were identified. In contrast, postsynaptic responses to optic nerve stimulation could not be detected in vivo until P39, around the time that retinal axons begin arborizing. Around this age density and numbers of total synapses began increasing in the retinorecipient layers of the colliculus. By P55-64, the numbers of retinal synapses had increased significantly and density and numbers of retinal and total synapses continued to increase up to P94-99. During this time the map is undergoing refinement and degenerating axons and synapses were present. The discrepancy between in vitro and in vivo onset of functional connections raises the question of when retinal activity reaches collicular cells in the intact, unanaesthetized animal and this will require investigation.

The outcome of suspected upper gastrointestinal bleeding with 24-hour access to upper gastrointestinal endoscopy: a prospective cohort study

BACKGROUND AND STUDY AIM

The aim was to evaluate the 30-day mortality after endoscopy for suspected upper gastrointestinal bleed, following the implementation of national audit guidelines at our hospital.

PATIENTS AND METHODS

All patients with suspected upper gastrointestinal bleeding, referred for endoscopy to our teaching hospital between October 2001 and December 2003, were included in a prospective cohort study.

RESULTS

A total of 716 patients with suspected upper gastrointestinal tract haemorrhage were referred for urgent endoscopy. The median age was 69 years (interquartile range 51 - 80 years). Bleeding from peptic ulcer remained the single most common endoscopic diagnosis (40 %). The overall re-bleeding rate for all patients with a gastrointestinal haemorrhage was 10 %. The overall 30-day mortality rate was 14.6 %. This was not significantly different from the mortality rate in 1995 of 10.5 % ( P = 0.11). Patients who died were significantly older (78 vs. 67 years, 95 %CI of the difference 5 to 12, P < 0.001). However, in only 29 % (30/105) was gastrointestinal haemorrhage stated in the death certificate as a factor which contributed to their death.

CONCLUSIONS

Our results show that implementing the good practice guideline has a limited impact on overall mortality because of contributing factors that are beyond the control of clinicians.