Frequency and distribution of patellar luxation in dogs. 134 cases (2000 to 2005)

This study investigated the frequency and distribution of patellar luxation in the dogs presented to the Chonbuk National University Animal Medical Centre during January 2000 to September 2005. Patellar luxations were classified as medial or lateral, and unilateral or bilateral, were graded I to IV, and were subdivided according to age, sex and size of the dogs. The incidence of medial patellar luxation (MPL) was greater than the incidence of lateral patellar luxation (LPL) in both small and large dogs. Small-breed dogs were admitted almost exclusively with MPL. LPL was found uncommon; however it was observed more often in larger-breed dogs. Surgical correction was performed primarily in the dogs (165 stifles in 111 dogs) with grade II, III and IV patellar luxations following different surgical techniques. The combination of the surgical techniques was found to be more effective for the management of the disease. The prognosis was found to be favourable, because when the grade was low, the dog was younger, without cruciate ligament rupture, and as the surgical correction was performed with combination of more techniques.

Metastatic Crohn's disease in a Chinese girl

Metastatic Crohn's disease, in which non-caseating granulomatous infiltration of the skin occurs at sites separated from the gastro-intestinal tract by normal tissue, is the least common dermatologic manifestation of Crohn's disease. We report a 15-year-old girl with metastatic Crohn's disease presenting as granulomatous vulvar papules and nodules with typical histopathologic features. To the best of our knowledge, this is the first case of metastatic Crohn's disease in Chinese children reported in the English medical literature.

Glomeruloid haemangioma with cerebriform morphology in a patient with POEMS syndrome

A 40-year-old Chinese man presented with sensorimotor polyneuropathy, IgAlambda paraprotein, osteosclerotic bone lesions, hypertrichosis, and impotence with decreased testosterone and raised prolactin level. POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes) syndrome was diagnosed and he was treated with melphalan and prednisolone. After chemotherapy, other manifestations of POEMS syndrome developed, such as multiple haemangiomas over the chest and neck region, splenomegaly and generalized oedema. One haemangioma had a peculiar clinical morphology, similar to the appearance of cerebral gyri. Skin biopsy confirmed the diagnosis of glomeruloid haemangioma. Chemotherapy was then switched to cyclophosphamide and prednisolone, resulting in further improvement in muscle power and hypertrichosis. To our knowledge, this is the first report on a clinically distinctive morphology of glomeruloid haemangioma, and its recognition may increase the index of suspicion for early skin biopsy.

RACK1 inhibits colonic cell growth by regulating Src activity at cell cycle checkpoints

Previously, we showed that Src tyrosine kinases are activated early in the development of human colon cancer and are suppressed as intestinal cells differentiate. We identified RACK1 as an endogenous substrate, binding partner and inhibitor of Src. Here we show (by overexpressing RACK1, depleting Src or RACK1 and utilizing cell-permeable peptides that perturb RACK1's interaction with Src) that RACK1 regulates growth of colon cells by suppressing Src activity at G(1) and mitotic checkpoints, and consequently delaying cell cycle progression. Activated Src rescues RACK1-inhibited growth of HT-29 cells. Conversely, inhibiting Src abolishes growth promoted by RACK1 depletion in normal cells. Two potential mechanisms whereby RACK1 regulates mitotic exit are identified: suppression of Src-mediated Sam68 phosphorylation and maintenance of the cyclin-dependent kinase (CDK) 1-cyclin B complex in an active state. Our results reveal novel mechanisms of cell cycle control in G(1) and mitosis of colon cells. The significance of this work lies in the discovery of a mechanism by which the growth of colon cancer cells can be slowed, by RACK1 suppression of an oncogenic kinase at critical cell cycle checkpoints. Small molecules that mimic RACK1 function may provide a powerful new approach to the treatment of colon cancer.

The placentas of patients with severe acute respiratory syndrome: a pathophysiological evaluation

Aims

The pathology of the placentas delivered from pregnant women who had severe acute respiratory syndrome (SARS) in Hong Kong was studied.

Methods

The pathology of the placentas was retrospectively studied in detail and compared with control sets. The clinical data of the women and neonates were also reviewed.

Results

A total of seven placentas were studied. The placentas from two women convalescent from SARS in the first trimester were normal. In three placentas delivered in the acute stage of SARS, there were increases in intervillous or subchorionic fibrin which might be related to disturbances in maternal placental blood flow due to the hypoxic respiratory disease. Extensive fetal thrombotic vasculopathy (FTV) with sharply demarcated zones of avascular fibrotic villi was noted in the placentas of two patients convalescent from SARS in the third trimester. Both pregnancies had intrauterine growth retardation, oligohydramnios and newborns small for gestation. The aetiology of the FTV might be related to thrombotic tendency due to SARS or placental hypoxia.

Conclusions

This report highlights placental pathology that was probably the result of pathophysiological alteration of the maternal fetal unit during SARS. Further studies are required to delineate the relationship between severe maternal respiratory disease, placental pathology and pregnancy outcome.

PEGylated glucagon-like peptide-1 displays preserved effects on insulin release in isolated pancreatic islets and improved biological activity in db/db mice

AIMS/HYPOTHESIS

The rapid degradation and clearance of glucagon-like peptide-1 (GLP-1) by the enzymes dipeptidyl peptidase-IV and neutral endopeptidase 24.11 are the main impediments to the development of GLP-1 as a potential glucose-lowering agent. In this study, new enzyme-resistant polyethylene glycol (PEG)-conjugated GLP-1 analogues were designed and examined for metabolic stability and biological potency.

MATERIALS AND METHODS

Two mono-PEGylated GLP-1 analogues, N-terminally modified N-PEG/GLP-1 and Lys-modified Lys-PEG/GLP-1, were prepared. Stability was tested in plasma and tissue extracts. In vitro insulin release studies were performed using isolated rat pancreatic islets, while in vivo glycaemic responses were measured in db/db mice.

RESULTS

The half-life of Lys-PEG/GLP-1 was 40-, 10- and 28-fold longer than that of GLP-1 in plasma, liver and kidney homogenates, respectively. Lys-PEG/GLP-1 stimulated insulin secretion in the islets in a dose- and glucose-dependent manner, and was as potent as GLP-1. In contrast, N-PEG/GLP-1 showed extended metabolic stability but had significantly lower biological activity. The administration of Lys-PEG/GLP-1 (9 nmol/kg i.p.) to non-fasted db/db mice stabilised glycaemia (p<0.001), whereas GLP-1 (9 nmol/kg) only caused small changes in glucose level. During OGTT in fasted db/db mice, Lys-PEG/GLP-1 administered at 1, 3 and 9 nmol/kg (i.p.) reduced the glucose AUC(0-3h) by 48.7+/-9.4, 55.0+/-2.9 and 63.4+/-2.5%, respectively, compared with placebo (p<0.01), whereas GLP-1 (9 nmol/kg) lowered the glucose level by 39.5+/-12.9% (p<0.01).

CONCLUSIONS/INTERPRETATION

This study demonstrates that site-specific PEGylated GLP-1 analogues are resistant to degradation. The enhanced biological potencies of these analogues highlight their potential as new, GLP-1-like glucose-lowering agents.

Fusion of the HSV-1 tegument protein vp22 to cytosine deaminase confers enhanced bystander effect and increased therapeutic benefit

A major limitation in cancer gene therapy, specifically gene-dependent enzyme prodrug therapy (GDEPT), is inefficient gene delivery and expression. The suicide gene cytosine deaminase (CD) and its substrate, 5-fluorocytosine (5-FC), have been extensively explored due to the inherent 'bystander' effect achieved through diffusion of the toxic metabolite 5-fluorouracil (5-FU). In this study, we aimed to enhance this 'bystander' effect by fusing the Saccharomyces cerevisiae CD to the HSV-1 tegument protein vp22, a novel translocating protein. Two constructs were created: one with vp22 fused to CD (vp22CD) and a second wherein a truncated vp22, lacking the necessary residues for trafficking, fused to CD (delvp22CD). The generated 9L stable lines exhibited similar growth rates, enzyme expression, CD activity, and sensitivity to 5-FC and 5-FU. However, mixed population colony formation assays demonstrated greater bystander effect with the vp22CD fusion as compared to delvp22CD. This enhancement was maintained in vivo where 9L tumors expressing 20 or 50% vp22CD exhibited increased growth delay compared to the respective delvp22CD tumors. Moreover, adenoviral transduction of established wild-type 9L tumors showed increased growth delay with vp22CD (Ad-EF_vp22CD) as compared to equivalent CD (Ad-EF_CD) transduced tumors. Finally, confirming the increased efficacy, (19)F magnetic resonance spectroscopy (MRS) of vp22CD-expressing tumors demonstrated increased 5-FU levels as compared to tumors expressing the nontranslocating CD. These results together demonstrated that fusion of vp22 to CD resulted in CD translocation, which in turn amplified conversion of 5-FC to 5-FU in vivo and enhanced the therapeutic benefit of this GDEPT strategy.

Parallel, Solution Phase Synthesis of Dihydropyridine Miticides Via a Versatile Multicomponent Reaction

A novel class of highly active dihydropyridine miticides was prepared using a multicomponent reaction process. The initial lead was rapidly optimized using solution phase parallel synthesis techniques and a positional scanning approach. Detailed structure-activity relationships were developed for the amino and carbonyl components of the molecule and used to select the best candidates for broad field testing. The chemistry, biology and toxicology of these compounds will be presented along with numerous structural variants of the reaction products.

Successful heart transplantation after 13 hours of donor heart ischemia with the use of HTK solution: a case report

INTRODUCTION

For heart transplantation (HTx), the recommended ischemic time (IT) for donor heart is not to exceed 6 hours. Though Dr Christiaan Barnard used a donor heart with IT of 16 hours, 50 minutes with a portable hypothermic perfusion system in 1981, the recorded IT of donor hearts reported recently is 8 hours, with no adverse effects.

CASE REPORT

The patient, a 14-year-old boy of blood type O, was diagnosed with cardiomyopathy at age 12. In early September 2003, the patient was recommended for HTx. His condition deteriorated 18 days later with low CO, elevated pulmonary vascular resistance, and frequent ventricular tachycardia, further complicated by pneumonia and multiorganism infections, which were contraindications for HTx. On September 22, 2003, a donor heart of blood type O was available 370 km away. Another patient of blood type B with severe heart failure was matched for the HTx. During the intervening time, another donor heart of blood type B became available locally. We matched the type B donor heart to the type B recipient. Since the type O donor heart seemed to be wasted, we performed HTx for the boy. Though preserved for 12 hours in cold cardioplegia, the donor heart was implanted with biatrial anastomosis that took 1 hour. The total IT of this donor heart was 13 hours. The recipient recovered and was discharged 3 months later.

CONCLUSIONS

The IT of 13 hours for this donor heart is believed to be a world record. Our experience demonstrates that preservation time of donor heart may exceed 6 hours.

Successful heart transplantation after 13 hours of donor heart ischemia with the use of HTK solution: a case report

INTRODUCTION

For heart transplantation (HTx), the recommended ischemic time (IT) for donor heart is not to exceed 6 hours. Though Dr Christiaan Barnard used a donor heart with IT of 16 hours, 50 minutes with a portable hypothermic perfusion system in 1981, the recorded IT of donor hearts reported recently is 8 hours, with no adverse effects.

CASE REPORT

The patient, a 14-year-old boy of blood type O, was diagnosed with cardiomyopathy at age 12. In early September 2003, the patient was recommended for HTx. His condition deteriorated 18 days later with low CO, elevated pulmonary vascular resistance, and frequent ventricular tachycardia, further complicated by pneumonia and multiorganism infections, which were contraindications for HTx. On September 22, 2003, a donor heart of blood type O was available 370 km away. Another patient of blood type B with severe heart failure was matched for the HTx. During the intervening time, another donor heart of blood type B became available locally. We matched the type B donor heart to the type B recipient. Since the type O donor heart seemed to be wasted, we performed HTx for the boy. Though preserved for 12 hours in cold cardioplegia, the donor heart was implanted with biatrial anastomosis that took 1 hour. The total IT of this donor heart was 13 hours. The recipient recovered and was discharged 3 months later.

CONCLUSIONS

The IT of 13 hours for this donor heart is believed to be a world record. Our experience demonstrates that preservation time of donor heart may exceed 6 hours.

Heart transplant coronary artery disease in Chinese recipients

BACKGROUND

Transplant coronary artery disease is the principle limiting factor for long-term survival of heart transplantation (HTx) recipients. We reviewed our data to assess the incidence of this disorder among Chinese HTx recipients and to compare it with the results of Western studies.

MATERIAL AND METHODS

From July 1988 to May 2002, 182 patients received 184 orthotopic HTx. One hundred sixty-three recipients survived for at least 1 year with available SPECT scans or coronary angiogram studies. The data set included donor characteristics, recipient characteristics, active cytomegalovirus (CMV) infection rate, rejection episodes, immunosuppressants, and human leukocyte antigen (HLA) mismatches.

RESULTS

Surgical mortality in our program was 4.3% and the actuarial freedom from coronary artery disease at 1, 3, and 5 years was 99%, 95%, and 92%, respectively. Angiogram results were stratified into coronary artery disease (n = 15) or absence of the disorder (n = 148) groups. Only older donor age showed statistical significance between the groups. Compared with the Western series, the present data show higher actuarial survival rates and freedom from coronary artery disease. There were statistically significant differences in regard to graft ischemia time, proportion of male recipients, ischemic heart disease, rejection episodes during the first year, and incidence of CMV infection.

CONCLUSIONS

SPECT scan can detect coronary artery disease before there is significant stenosis of the coronary artery with acceptable survival rates. Chinese HTx recipients show a lower incidence of the disorder, lower rates of ischemia heart disease, lower proportion of male gender, lower incidence of CMV infection, fewer rejection episodes during the first year, and less ischemic time than Western recipients, which maybe the contributing factors to their better survival.

Mutation analysis of hepatitis B virus promoters in chronically infected children

Hepatitis B viral (HBV) infection in early childhood is one of the leading causes of chronic hepatitis and liver cirrhosis that eventually lead to hepatic carcinoma. Despite the nationwide immunization programs to curtail the vertical transmission of HBV, childhood HBV infection through mothers is still occurring in Korea. As one of the efforts to understand the childhood HBV infection in Korea, four HBV promoter sequences in the sera of the chronically infected children were analyzed. Children harbored diverse viral variants as most of the chronically infected adult patients, but the deletion mutations were rare. The dominant viral sequences in the children were highly similar to the ones in the respective mothers, indicating that the maternal viruses were most likely transmitted to the children. The mutations in X, S1, S2/S promoters did not seem to show any correlation to the severity of the disease nor ages of the children. The mutations that showed some correlation to the severity of the disease were the mutations in C promoter, but the mutations did not seem to be vertically transmitted. Finally, the children with the elevated ALT/AST levels tended to have more child-specific variants suggesting that the accumulation of host-specific mutations might be associated with the development of clinical symptoms.

Development of a quantitative assay for SARS coronavirus and correlation of GAPDH mRNA with SARS coronavirus in clinical specimens

AIMS

To develop a quantitative reverse transcriptase polymerase chain reaction (Q-RT-PCR) for severe acute respiratory syndrome coronavirus (SARS-CoV) detection and explore the potential of using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA as an internal control to exclude false negative results.

METHODS

SARS-CoV and GAPDH mRNA were both measured in 26 specimens from 16 patients with SARS, 40 follow up specimens from the same batch of patients, and appropriate control subjects. The relation between SARS positivity and GAPDH mRNA concentration was investigated using the chi2 test. Increasing the sensitivity for SARS-CoV and GAPDH mRNA detection was investigated in follow up specimens in which SARS-CoV and GAPDH mRNA were not detected initially.

RESULTS

Varying amounts of SARS-CoV were found in the 26 SARS-CoV positive specimens and SARS-CoV was not detected in the 40 follow up specimens and controls. In addition, concentrations of GAPDH mRNA were significantly different between the patients with SARS, follow up specimens, and healthy controls (Kruskal-Wallis test, p<0.05). Moreover, GAPDH mRNA concentrations were highly correlated with SARS-CoV positivity (chi2 = 5.43; p<0.05). Finally, SARS-CoV and GAPDH mRNA were both detected in three follow up urine specimens that were initially negative when the amount of cDNA used was increased from 5 microl to 10 and 15 microl.

CONCLUSIONS

This Q-RT-PCR assay can be used to detect SARS-CoV. Moreover, GAPDH mRNA may be useful to rule out false negative results in SARS-CoV detection, and the current extraction method for urine may not be sensitive enough to detect low titres of SARS-CoV.

Performance of Large-Size Superconducting Coil in 0.21T MRI System

A high-temperature superconductor (HTS) was used on magnetic resonance imaging (MRI) receiver coils to improve image quality because of its intrinsic low electrical resistivity. Typical HTS coils are surface coils made of HTS thin-film wafers. Their applications are severely limited by the field of view (FOV) of the surface coil configuration, and the improvement in image quality by HTS coil is also reduced as the ratio of sample noise to coil noise increases. Therefore, previous HTS coils are usually used to image small in vitro samples, small animals, or peripheral human anatomies. We used large-size HTS coils (2.5-, 3.5-, and 5.5-in mean diameter) to enhance the FOV and we evaluated their performance through phantom and human MR images. Comparisons were made among HTS surface coils, copper surface coils, and cool copper surface coils in terms of the signal-to-noise ratio (SNR) and sensitivity profile of the images. A theoretical model prediction was also used to compare against the experimental result. We then selected several human body parts, including the wrist, feet, and head, to illustrate the advantage of HTS coil over copper coil when used in human imaging. The results show an SNR gain of 200% for 5.5-in HTS coil versus same size copper coils, while for 2.5- and 3.5-in coils it is 250%. We also address the various factors that affect the performance of large size HTS coils, including the coil-to-sample spacing due to cryogenic probe and the coil-loading effect.

Nuclear beta catenin as a potential prognostic and diagnostic marker in patients with colorectal cancer from Hong Kong

AIMS

To study the expression of nuclear beta catenin in patients with colorectal cancer, colorectal adenoma, and colorectal polyps to elucidate its role in carcinogenesis, and its potential for prognosis and diagnosis.

METHODS

The expression of nuclear beta catenin was studied by immunohistochemistry using paraffin wax embedded specimens. Sixty specimens each of colorectal carcinoma, colorectal adenoma, colorectal polyp, and normal colorectal specimens were analysed. The potential for prognosis was assessed by correlating nuclear beta catenin expression in 60 and 75 patients with colorectal cancer with lymph node metastasis and survival, respectively. The diagnostic capacity was explored by comparing nuclear beta catenin expression in 60 patients with colorectal cancer with other cytokeratin 20 (CK20) positive adenocarcinomas, namely: 30 colonic mucinous adenocarcinomas, 30 gastric adenocarcinomas, 27 pancreatic adenocarcinomas, and 12 ovarian mucinous adenocarcinomas.

RESULTS

Nuclear beta catenin expression was highly associated with progression of colorectal tissue from normal epithelial tissue, polyps, adenomas, to carcinomas (r = 0.875; p < 0.0001). Nineteen patients with colorectal adenoma who subsequently developed colorectal carcinoma had higher nuclear beta catenin expression than those with colorectal adenomas alone (p < 0.0001). Moreover, those patients with colorectal cancer and high nuclear beta catenin expression had a higher incidence of lymph node metastasis (chi(2) = 16.99; p < 0.005) and shorter overall survival (p < 0.0001). Finally, nuclear beta catenin expression in colorectal adenocarcinomas was significantly higher than in other CK20 positive adenocarcinomas.

CONCLUSIONS

Nuclear beta catenin expression is a potential prognostic factor in patients with colorectal cancer, and together with CK20, it could be used to identify colorectal carcinoma in the Hong Kong population.

Specific heat and Lindemann-like parameter of metallic clusters: Mono- and polyvalent metals

The Brownian-type molecular dynamics simulation is revisited and applied to study the thermal and geometric properties of four mono- and two polyvalent metallic clusters. For the thermal property, we report the specific heat at constant volume CV and study the solid-liquid-like transition by scrutinizing its characteristic. For the geometric property, we calculate the root mean square relative bond-length fluctuation delta as a function of increasing temperature. The thermal change in delta reflects the movement of atoms and hence is a relevant parameter in understanding the phase transition in clusters. The simulated results for the CV of alkali and aluminum clusters whose ground state structures exhibit icosahedral symmetry generally show one phase transition. In contrast, the tetravalent lead is quite often seen to exhibit two phase transitions, a premelting process followed by a progressive melting. In connection with the premelting scenario, it is found here that those (magic number) clusters identified to be of lesser stability (among other stable ones) according to the second energy difference are clusters showing a greater possibility of undergoing premelting process. This energy criterion applies to aluminum clusters nAl=28 and 38. To delve further into the thermal behavior of clusters, we have analyzed also the thermal variation of deltaT and attempted to correlate it with CV(T). It turns out that the premelting (if exist) and melting temperatures of the smaller size clusters (n less, similar 50) extracted from CV do not always agree quantitatively with that deduced from delta.

Enhancement of the resolution of surface plasmon resonance biosensors by control of the size and distribution of nanoparticles

A new resolution-enhanced surface plasmon resonance (SPR) biosensor offers a tenfold improvement in resolution compared with conventional SPR biosensors in the detection of the surface coverage of biomaterials. The proposed optical biosensor, based on the attenuated total-reflection method, excites both the surface plasmons and particle plasmons to enhance the local electromagnetic field by control of the size and volume fraction of embedded Au nanoparticles to increase the resolution of the device. The SPR biosensor design is based on the Maxwell-Garnett model and the Fresnel equations, and the device is fabricated with a cosputtering deposition system.

Effect of TCDD on corpus cavernosum histology and smooth muscle physiology

A polyhalogenated aromatic hydrocarbon, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is one of the most potent toxic environmental pollutants. Decreases in spermatogenesis and the ability to conceive and carry a pregnancy to term are the most sensitive signs of reproductive toxicity by TCDD in the mammal, but no report of its effect on the erectile function exists. We performed this study to investigate the effect of TCDD on the erectile function. New Zealand white rabbits were treated intraperitoneally with 1 microg/kg of TCDD. At 4 (Gr I) and 8 (Gr II) weeks after the administration of TCDD, cavernosal tissues were harvested for strip study in the organ bath and testes were prepared for histologic examination. Compared to the maximal amplitude of 17.1+/-4.12 mN in normal control (Gr III), the contractions to cumulative concentrations of NE (10(-8)-10(-4) M) were significantly decreased to 6.57+/-1.34 and 5.45+/-1.01 mN in Groups I and II, respectively. Compared to 51.12+/-7.38% in Gr III, relaxation to cumulative concentration (10(-8)-10(-4) M) of acetylcholine was significantly decreased to 17.25+/-2.17% (Gr I) and 9.73+/-2.17% (Gr II) at a concentration of 10(-4) M, respectively. Compared to 75.12+/-13.18% in Gr III, relaxation to cumulative concentration (10(-8)-10(-4) M) of SNP was significantly decreased to 31.49+/-7.89% (Gr I) and 18.54+/-6.12% (Gr II) at a concentration of 10(-4) M, respectively. Histologically, intracavernosal fibrosis, abnormal subtunical deposition of fat and decreased sinusoidal space with consequent increase of trabecular smooth muscle contents were identified in TCDD-treated groups. In TCDD-treated animals, seminiferous tubules showed a decrease of germ cells with vacuolar degeneration and apoptotic cells. Spermatids were hardly seen. These results suggest that TCDD inhibits spermatogenesis and has a potential harmful effect on erectile function via changes of corpus cavernosum histology and smooth muscle physiology.

Corticosteroid therapy in a Chinese patient with nephropathy associated with human immunodeficiency virus infection

A 52-year-old man with 6 years' history of human immunodeficiency virus infection who was receiving highly active antiretroviral therapy presented with acute renal failure and nephrotic syndrome. Renal biopsy revealed features consistent with nephropathy associated with human immunodeficiency virus infection. Treatment consisted of intravenous methylprednisolone followed by oral prednisolone. The patient's renal function improved, although proteinuria persisted. Human immunodeficiency virus-associated nephropathy is very rare in Asian populations and is more common among blacks. To the best of our knowledge, this is the first documented case of nephropathy associated with human immunodeficiency virus infection occurring in Hong Kong.

Radiographic contrast study of the upper gastrointestinal tract of eight dogs using carboxymethylcellulose mixed with a low concentration of barium sulphate

To evaluate the efficacy of a mixture of barium and carboxymethylcellulose (CMC) suspension in upper gastrointestinal contrast studies, and to determine its optimal concentration and method for use, eight healthy beagle dogs underwent conventional upper gastrointestinal contrast imaging and a modified procedure using a mixture of barium sulphate and CMC. Four different procedures were carried out on the dogs at weekly intervals. In the first, the dogs were administered 10 ml/kg of 60 per cent barium suspension for conventional study of the upper gastrointestinal tract. The second, third and fourth procedures involved modified methods in which the dogs were given 10 ml/kg of a mixture of 25 per cent barium and 0.5 per cent CMC prepared to a low, moderate or high viscosity, respectively. All four procedures were evaluated by four criteria: the quality of the images obtained, the translucency and distensibility of the bowel, and the transit time. The method of imaging which used a moderately viscious CMC formulation provided excellent image quality, high translucency, a rapid transit time and suitable bowel distension to enable more precise diagnosis of disorders of the gastrointestinal tract.

Breakage of resistance to Cucumber mosaic virus by co-infection with Zucchini yellow mosaic virus : enhancement of CMV accumulation independent of symptom expression

Resistance to the cucumovirus Cucumber mosaic virus (CMV) in cucumber cv. Delila was manifested as a very low level of accumulation of viral RNA and capsid protein, and an absence of CMV-induced symptoms. In addition, resistance was observed at the single cell level, with a reduction in accumulation of CMV RNAs, compared to accumulation in cells of the susceptible cucumber cv. Bet Alpha. Resistance to CMV in cv. Delila was broken by co-infection with the potyvirus Zucchini yellow mosaic virus (ZYMV). Resistance breakage in cv. Delila plants was manifested by an increase in the accumulation of (+) and (-) CMV RNA as well as CMV capsid protein, with no increase in the level of accumulation of ZYMV. Resistance breakage in the resistant cultivar by ZYMV also occurred at the single cell level. Thus, synergistic interactions known to occur between a potyvirus and a cucumovirus led to resistance breakage during a double infection. However, resistance breakage was not accompanied by an increase in disease symptoms beyond those induced by ZYMV itself. On co-inoculation with an asymptomatic variant of ZYMV-AG an enhancement of CMV infection occurred without disease manifestation. Consequently, intensification of viral RNA and capsid protein accumulation can occur without a corresponding increase in disease development, suggesting that different host genes regulate viral accumulation and disease development in the CMV-resistant cucumber plants.

Dynamic dead space in face masks used with noninvasive ventilators: a lung model study

The aim of this study was to determine what the influence of different designs of face masks and different noninvasive ventilator modes would be upon total dynamic dead space. Using a spontaneous breathing model, total dynamic dead space was measured when using 19 commercially available face masks and a range of ventilators in various ventilation modes. Total dynamic dead space during spontaneous ventilation was increased above physiological dead space from 32% to 42% of tidal volume by using face masks. The use of noninvasive ventilation modes such as bilevel and continuous positive airway pressure, with continuous pressure throughout the expiratory phase, reduced total dynamic dead space to approach physiological dead space with most face masks. Pressure assist and pressure support ventilation decreased total dynamic dead space to a lesser degree, from 42% to 39% of tidal volume. Face masks with expiratory ports over the nasal bridge resulted in beneficial flow characteristics within the face mask and nasal cavity, so as to decrease total dynamic dead space to less than physiological dead space from 42% to 28.5% of tidal volume. Exhaust ports over the nasal bridge in face masks effect important decreases in dynamic dead space provided positive pressure throughout the expiratory phase is used.

Intranasal delivery of PEGylated salmon calcitonins: hypocalcemic effects in rats

To evaluate the hypocalcemic effect of polyethylene gtycol-conjugated salmon calcitonins (PEG-sCT) in rats, mono-PEGylated sCTs (mono-PEG-sCTs) and unmodified sCT were administered via the intranasal route and serum calcium levels were measured by colorimetric assay using o-cresolphthalein. Mono-PEG-sCTs were prepared with different sizes of succinimidyl succinate monomethoxy PEG molecules (PEG2K), PEG5K, PEG12K) and characterized by HPLC and MALDI-TOF mass spectrometry. Nasal instillation of mono-PEG2K-sCT at a dose of 2 IU/kg resulted in sustained reduction in serum calcium levels over 8 hr, with a maximum reduction (% maxd) of 13% after 6 hr of application. Whereas unmodified sCT showed a transient decrease in serum calcium levels with the maximum reduction (5%) observed after 30 min of administration. The overall reductions in serum calcium levels expressed as the net change in AUC relative to control in 8 hr were 11.9 +/- 0.2, 4.6 +/- 0.7, and 2.6 +/- 0.7% for mono-PEG2K-, mono-PEG5K-, and mono-PEG12K-sCT, respectively, compared to 3.2 +/- 0.6% for unmodified sCT. The relative bioavailability of nasally administered 2 IU/kg of mono-PEG2K-sCT was approximately 4-fold higher than nasally administrated unmodified sCT, and the absolute bioavailability was approximately 91% of intravenously injected sCT in 8 hr. It can be concluded that the intranasal absorption of mono-PEG-sCTs was inversely related to the molecular weights of the PEG attached. Of the PEGylated sCTs examined, mono-PEG2K-sCT showed the most pronounced hypocalcemic effect. Therefore the intranasal application would probably be an alternative route of administration for mono-PEG-sCTs in achieving sustained calcium-lowering effects.

Reinduced expression of developmental proteins (nestin, small heat shock protein) in and around cerebral arteriovenous malformations

Intermediate filament (IF) nestin and small heat shock protein (sHSP) are developmentally regulated proteins. Nestin is highly expressed on proliferating neuroepithelial stem cells of the developing central nervous system (CNS). During the developmental neurulation stage, nestin is replaced by mature neuronal (neurofilament) or glial cell-specific IFs (glial fibrillary acidic protein, GFAP). Several pathologic states induce astrocytes to synthesize nestin transiently in the mature brain. However, the exact nature of the embryonic conversion from nestin to mature cytoskelton is unclear. In an attempt to define the effect of ischemic hemodynamic stress caused by cerebral arteriovenous malformation (AVM) on the brain parenchyma, we examined the synthesis and cellular distribution of sHSP and nestin in vascular elements of AVMs and in the gliotic area surrounding AVMs. Ten consecutively collected surgical specimens meeting the histological criteria for AVM were immunohistochemically stained using primary antibodies for nestin, HSP27 and alphaB-crystallin. Nestin, HSP27 and alphaB-crystallin mRNA expressions were examined by reverse transcriptase-polymerase chain reaction (RT-PCR). Nestin expression is reinduced not only in reactive astrocytes, but also in endothelial cells in the surrounding gliotic tissue of the cerebral AVM. These cells also expressed sHSP (HSP27, alphaB-crystallin) that maintain the integrity of the IF network and prevent unfolding of cellular proteins induced by various stresses. RT-PCR showed the increased expression of sHSP and nestin mRNA in the AVM specimens. These results indicate that embryonic reversion of the mature cytoskeleton to nestin and the increased expression of sHSP in response to cerebral injury are associated with increased wall tension caused by dilating AVM vessels and with the hemodynamic stress that surrounds AVMs.

Three patients with orbital xanthogranuloma and non-progressive haematological abnormalities

Orbital xanthogranuloma is a rare dermatological condition characterized by its bilateral and rather symmetrical subcutaneous granulomatous infiltration around the eyes. It shares morphological similarities with other xanthogranulomatous diseases such as juvenile or adult type xanthogranuloma, necrobiotic xanthogranuloma and cutaneous infiltration in Erdheim-Chester disease, and should be differentiated from them. Three elderly Chinese patients with this condition were found to have underlying haematological abnormalities: normochromic normocytic anaemia, thrombocytopenia or eosinophilia. Their skin lesions remained localized and associated haematological abnormalities stable for up to 7 years. Haematological abnormalities were also reported in previous cases and this finding is unlikely to be coincidental; however, its clinical significance remains unknown.