Metabolism of cAMP to adenosine: role in vasodilation of rat pial artery in response to hypotension

The purpose of this experiment was to examine whether the cAMP-adenosine pathway is implicated in the autoregulatory vasodilation in response to hypotension. Suffusion with cAMP (1-100 micromol/l) or adenosine (0.01-10 micromol/l) caused a sustained vasodilation of the resting pial arteries in a concentration-dependent manner. In contrast, N6,2'-O-dibutyryl-cAMP and 8-bromo-cAMP exerted a weak dilation at high concentration (100 micromol/l). The vasodilation to cAMP (1-100 micromol/l), adenosine (0.01-10 micromol/l), and hypotension was significantly reduced by pretreatment with 3,7-dimethyl-1-propargylxanthine (1 micromol/l), an A2 receptor antagonist, as well as 3-isobutyl-1-methylxanthine (3 micromol/l), an inhibitor of endo- and ectophosphodiesterase, 1, 3-dipropyl-8-p-sulfophenylxanthine (100 micromol/l), an inhibitor of ecto-5'-phosphodiesterase, or alpha,beta-methylene-adenosine 5'-diphosphate (100 micromol/l), an inhibitor of ecto-5'-nucleotidase. However, 8-cyclopentyltheophylline (1 micromol/l), an A1 antagonist, did not elicit a similar response. The increased release of adenosine when the cortical surface was suffused with cAMP (100 micromol/l) was significantly reduced by 3-isobutyl-1-methylxanthine, 1,3-dipropyl-8-p-sulfophenylxanthine, and alpha,beta-methylene-adenosine 5'-diphosphate (each 100 micromol/l). These results indicate that the cAMP-adenosine pathway as a viable metabolic mechanism is implicated in the production of adenosine in the rat pial artery and contributes to the regulation of vasodilation in response to hypotension.

Effect of omega-conotoxin GVIA and omega-agatoxin IVA on the capsaicin-sensitive calcitonin gene-related peptide release and autoregulatory vasodilation in rat pial arteries

This study assesses the effect of neuronal voltage-sensitive Ca2+ channel blockers, omega-conotoxin GVIA (CTX), and omega-agatoxin IVA (AgTX) on the vasodilation and release of calcitonin gene-related peptide (CGRP), both of which were induced by either application of capsaicin or acute stepwise hypotension. Changes in pial arterial diameter were determined directly through a closed cranial window. The vasodilation of pial artery induced by either CGRP (0.1 micromol/L) or capsaicin (0.3 micromol/L) was significantly inhibited by CGRP(8-37) (0.1 micromol/L) (P < 0.05 and P < 0.05, respectively). The autoregulatory vasodilation to acute stepwise hypotension was severely attenuated by pretreatment with either CTX or AgTX. When the hypotension was kept for 2, 4, and 10 minutes, the releasable CGRP-like immunoreactivity (CGRP-LI) level (vehicle, 13.4+/-1.5 fmol/mm2/30 min) by 10 micromol/L capsaicin from the isolated pial arteries was significantly reduced in the 4- and 10-minute hypotension groups (11.3+/-1.2 fmol/mm2/30 min, P < 0.05, and 11.1+/-1.5 fmol/mm2/30 min, P < 0.05, respectively), but not in 2-min group. Moreover, the CGRP-LI level released by 10 micromol/L capsaicin (13.7+/-0.9 fmol/mm2/30 min) also was significantly depressed by pretreatment with 1 micromol/L CTX to 10.4+/-1.0 fmol/mm2/30 min (P < 0.01) and with 0.1 micromol/L AgTX to 8.7(1.7 fmol/mm2/30 min (P < 0.001), as well as by pretreatment with 10 micro-mol/L capsaicin (6.0+/-1.6 fmol/ mm2/30 min, P < 0.001). These results suggest that the neuronal N- and P-type voltage-sensitive Ca2+ channels are implicated in the release of CGRP from capsaicin-sensitive perivascular sensory nerves in response to acute hypotension, and that the released CGRP may contribute to the autoregulatory vasodilation in the cerebral microcirculation.

Cyclic vomiting syndrome in South-East Asian children

OBJECTIVE

To describe the clinical features, management and outcome of children with cyclic vomiting syndrome (CVS) from South-East Asia.

METHODOLOGY

Retrospective review of all children who fulfilled the diagnostic criteria of CVS and who were seen at Department of Paediatrics, University of Malaya Medical Centre, Kuala Lumpur and Paediatric Unit, Penang Hospital, Penang, Malaysia from 1987 to 1997.

RESULTS

Eight children with CVS were seen at the two units during the study period, five girls and three boys. All had cyclical, self-limited episodes of nausea and vomiting with symptom-free intervals. The mean age of onset was 5.9 years. The clinical features were similar to other series described in the literature. Only two of the eight children were described as 'perfectionist'. Two children identified stress as precipitating factors. Therapy to reduce the number of emeses during acute attacks and to prevent subsequent attacks had been ineffective.

CONCLUSION

There are similarities and differences in CVS from South-East Asian children as compared to those described in the literature.

Nocardia osteomyelitis in a pachymeningitis patient: an example of a difficult case to treat with antimicrobial agents

Antimicrobial agents played a miraculous role in the treatment of bacterial infections until resistant bacteria became widespread. Besides antimicrobial-resistant bacteria, many factors can influence the cure of infection. Nocardia infection may be a good example which is difficult to cure with antimicrobial agents alone. A 66-year-old man developed soft tissue infection of the right buttock and thigh. He was given prednisolone and azathioprine for pachymeningitis 3 months prior to admission. Despite surgical and antimicrobial treatment (sulfamethoxazole-trimethoprim), the infection spread to the femur and osteomyelitis developed. The case showed that treatment of bacterial infection is not always as successful as was once thought because recent isolates of bacteria are more often resistant to various antimicrobial agents, intracellular parasites are difficult to eliminate even with the active drug in vitro, and infections in some sites such as bone are refractory to treatment especially when the patient is in a compromised state. In conclusion, for the treatment of infections, clinicians need to rely on laboratory tests more than before and have to consider the influence of various host factors.

Radiographic parameters of acetabulum for dysplasia in Korean adults

We analyzed plain radiographs of 591 normal adult hips of various parameters to evaluate the radiological characteristics of the hip joint including the center-edge (CE) angle, acetabular angle, acetabular depth, acetabular roof obliquity and roof angle, and also to verify the rate of acetabular dysplasia. The CE angle was negatively correlated with acetabular angle and acetabular obliquity, but it was positively correlated with acetabular depth and roof angle. The rate of acetabular dysplasia (CE angle < 20 degrees) was 1.8%. We concluded that the CE angle and acetabular angle are more useful parameters for the diagnosis of acetabular dysplasia because there was no significant difference with advancing age and gender, as well as relatively small standard deviations.

Effect of rebamipide on liver damage and increased tumor necrosis factor in a rat model of endotoxin shock

We investigated the effect of rebamipide, a novel antiinflammatory agent, on liver damage in a rat model of circulatory shock induced by bacterial endotoxin (E. coli lipopolysaccharide, LPS). Endotoxemia for 6 hr resulted in a 5.9-fold rise in the serum levels of nitrite (P < 0.05) with a significant rise in the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactic dehydrogenase (LDH), suggestive of liver dysfunction. The increased activities of serum ALT, AST, and LDH, but not serum nitrite were significantly inhibited by rebamipide (100 mg/kg, orally for five days). Myeloperoxidase activity in the liver was significantly elevated in the rats with endotoxemia by 2.4-fold (P < 0.05), which was also significantly inhibited by rebamipide. Upon LPS injection, serum TNF-alpha levels peaked at 1 hr after LPS (from 167.4 +/- 20.0 to 1570.0 +/- 100.0 pg/ml) and thereafter rapidly declined. The increased TNF-alpha level measured at 1 hr was significantly inhibited by pretreatment with rebamipide (100 mg/kg for five days). It is suggested that rebamipide exerts a strong protective effect on the LPS-induced liver damage through inhibition of activation of neutrophils and TNF-alpha production.

Intestinal lymphangiectasia--a report of three Chinese children in Malaysia

This is a report of 3 Chinese children with intestinal lymphangiectasia in Malaysia. Two children responded to a low fat diet and medium-chain triglyceride supplement. The third child has recurrent chylous ascites. None of the children has recurrent infections despite low CD4+ cells and low levels of IgG and IgA. Intestinal lymphangiectasia is a rare congenital disorder of the mesenteric lymphatic that leads to the obstruction of the lymphatics of the intestine and protein losing enteropathy. Restriction of dietary fat intake will usually result in remission. Recurrent chylous ascites is a problem and management can be difficult.

Non-typhoid Salmonella gastroenteritis

OBJECTIVE

To study the clinical features of non-typhoid Salmonella gastroenteritis and the incidence, risk factors and outcome of invasive complications in urban Malaysian children. To describe the serotypes of Salmonella species isolated and the pattern of antibiotic susceptibility.

METHODOLOGY

Retrospective review of a group of 131 children with non-typhoid Salmonella gastroenteritis seen at the University Hospital, Kuala Lumpur, Malaysia from January 1994 to December 1996.

RESULTS

Sixty-seven percent were infants below one year of age. Fever and vomiting were seen in nearly half of children. Seven children (5.3%) had invasive complications: 5 bacteraemia and 2 meningitis. Age below 6 months, fever > 38.0 degrees C, and dehydration on admission were significantly associated with invasive complications. The commonest serotypes isolated were S. enteritidis, S. paratyphi B, and S. bovis-morbificans. A total of 94-100% of isolates were susceptible to commonly prescribed antibiotics.

CONCLUSIONS

Children with Salmonella gastroenteritis below 6 months of age who are febrile and dehydrated should be treated empirically with antibiotics until the result of blood culture is available.

Feeding diets containing high levels of milk products or cellulose decrease urease activity and ammonia production in rat intestine

Three studies were done to determine the effect of feeding diets containing high levels of a readily fermentable carbohydrate (lactose in milk or yogurt, or pure lactose) or an undigestible, unfermentable diluent (alpha-cellulose) on urease (EC 3.5.1.5) activity and net ammonia production in the rat gastrointestinal (GI) contents. Rats (170-200 g) were fed a control diet or diets containing 55% dried milk or 55% dried yogurt, 25% lactose or 10% alpha-cellulose. Feeding diets containing milk or yogurt decreased urease activity to approximately 11% of the control value in the small intestine (on the basis of grams of collected contents or total contents), and to 50% in the large intestine (only on the basis of grams of collected contents). Feeding the diet containing 25% lactose also decreased urease activity (on the basis of grams of collected contents or total contents) to about 20% of the control value in the small intestine, but not (P > 0.05) in the large intestine. Net ammonia production rate was correlated (r2 = 0.98) with urease activity in the large intestinal contents, and the rate of ammonia production from ureolysis represented about two thirds of the total. Feeding the cellulose diet decreased (P < 0.05) both urease activity and net ammonia production in the large intestine to approximately 30% of the control value. Weights of tissue and contents of the large intestine were much higher (P < 0.01) in rats fed diets containing milk products or lactose than in the control rats, but were not affected by consumption of the cellulose diet. Results of our studies indicate that feeding diets containing high levels of milk products (lactose) or cellulose reduces urease activity and net ammonia production in the rat intestine, and thus may be beneficial for improving animal and human health.

Thy-1, a novel marker for angiogenesis upregulated by inflammatory cytokines

We identified the cell surface glycoprotein Thy-1 on the endothelium of newly formed blood vessels in four models of angiogenesis in adult rats. Anti-Thy-1 staining showed that Thy-1 was upregulated in adventitial blood vessels after balloon injury to the carotid artery. Preabsorption with a rat Thy-1-Ig fusion construct eliminated all immunoreactivity and thus confirmed the specificity of the Thy-1 staining. Thy-1 was also expressed in the endothelium of small blood vessels formed after tumor implantation in the cornea, in periureteral vessels formed after ligation of the renal artery, and in small blood vessels of the uterus formed during pregnancy. In contrast with its expression during adult angiogenesis, Thy-1 was not expressed in the endothelium of blood vessels during embryonic angiogenesis. In vitro, the inflammatory cytokines interleukin-1beta and tumor necrosis factor-alpha upregulated Thy-1 mRNA by 8- and 14-fold, respectively. Vascular endothelial growth factor, basic fibroblast growth factor, transforming growth factor-beta, and platelet-derived growth factor-BB had no effect on Thy-1 mRNA. Thus, Thy-1 appears to be a marker of adult but not embryonic angiogenesis. The upregulation of Thy-1 by cytokines but not growth factors indicates the importance of inflammation in the pathogenesis of adult angiogenesis.

RFLP mapping of the centromere of chromosome 4 in maize using isochromosomes for 4S

The centromere of maize chromosome 4 was previously localized to a 26-cM interval using molecular markers and B-A translocations. The objective of the present study was to refine the placement of the centromere using secondary trisomics. Two independently isolated secondary trisomics (having an isochromosome plus two normal homologs) for 4S were recovered. RFLP analysis of populations segregating for them placed the centromere of chromosome 4 between bnl15.45 and bnl7.20, two RFLP loci that are 5.4-cM apart on the UMC map and 11.5-cM apart on the BNL map.

Cloning of a cDNA encoding phospholipase D from Pimpinella brachycarpa

Phospholipase D (PLD, EC 3.1.4.4) has been known to be related to various cellular processes in plants. To gain an understanding of the property of the enzyme in Pimpinella brachycarpa, the cDNA of the enzyme was isolated by PCR with degenerate primers, cDNA library screening, and 5' RACE. The full-length PLD cDNA is 2859 bp long and contains an open reading frame of 2424 bp coding for a polypeptide of 808 amino acids. The deduced enzyme has a calculated molecular mass of 91.7 kDa and pI of 5.86. The percent identity and similarity values of P. brachycarpa PLD with those of other PLDs in plants are 70 approximately 78 and 84 approximately 95, respectively. It was identified that PLD from P. brachycarpa has HQKIVVVD and HAKMMIVD sequences which were homologous with a duplicated HXKXXXXD motif that has been conserved in PLDs from plants, animals, and yeast. Based on the analysis of amino acid similarity, it is believed that PLD from P. brachycarpa is an alpha form which is distinct from PLD beta reported recently. The N-terminus is homologous to the C2 domain which is present in a number of different proteins involved in signal transduction and membrane trafficking in animals. Southern and northern blot analyses indicated that PLD was expressed from one copy of PLD gene in the genome of P. brachycarpa.

Topographical relationship of the facial and vestibulocochlear nerves in the subarachnoid space and internal auditory canal

PURPOSE

Our purpose was to investigate the topographical relationship of the facial and vestibulocochlear nerves from the brain stem through the internal auditory canal.

METHODS

We dissected 15 formalin-fixed cadaveric heads and performed MR examinations in 35 healthy subjects in order to examine the topographical relationship of the facial and vestibulocochlear nerves. The cadaveric dissections and the in vivo MR imaging findings were compared indirectly.

RESULTS

The relationship between the facial and vestibulocochlear nerves showed some variation among individuals and according to the location of the nerves within the cisterns or canal. Near the brain stem, 53% of the vestibulocochlear nerves were partially segmented on MR images. The vestibulocochlear nerve was completely divided into separate nerves only in the most lateral portion of the canal, except in three cadaveric dissections, in which separation of the superior vestibular nerve was seen near the brain stem. The facial and cochlear nerves were of similar size on 36% of the MR images. The superior vestibular nerve was larger than the inferior vestibular nerve on 81% of the MR images.

CONCLUSION

The appearance of the facial and vestibulocochlear nerves was variable but followed certain consistent patterns.

Localization of the high-affinity glutamate transporter EAAC1 in rat kidney

Most amino acids filtered by the glomerulus are reabsorbed in the kidney via specialized transport systems. Recently, the cDNA encoding a high-affinity glutamate transporter, EAAC1, has been isolated and shown to be expressed at high levels in the kidney. To determine the potential role of EAAC1 in renal acidic amino acid reabsorption, the distribution of EAAC1 mRNA and protein in rat kidney was examined. In situ hybridization revealed that EAAC1 mRNA is expressed predominantly in S2 and S3 segments of the proximal tubules and at low levels in the inner stripe of outer medulla and inner medulla. Polyclonal antibodies raised against the carboxy terminus of EAAC1 recognized a single band of approximately 70 kDa on Western blots of membrane protein from kidney cortex and medulla. Immunofluorescence microscopy revealed intense signals in the luminal membrane of S2 and S3 segments and weaker signals in S1 segments, descending thin limbs of long-loop nephrons, medullary thick ascending limbs, and distal convoluted tubules. These results are consistent with EAAC1 encoding the previously described apical high-affinity glutamate transporter in the kidney that mediates reabsorption of acidic amino acids in tubules beyond early proximal tubule S1 segments. Potential additional roles of EAAC1 in acid/base balance, cell volume regulation, and amino acid metabolism are discussed.

Frontal fibrosing alopecia in a postmenopausal woman

A case is presented of a 52-year-old woman in whom clinical and histopathologic findings suggested cicatricial alopecia. Our patient had an uncommon, but distinctive, clinical presentation. It was characterized by bandlike frontal hair loss. This was recently described as patterned cicatricial alopecia, presented in a recent study as postmenopausal frontal hairline recession with scarring. Our patient's case should be differentiated from recognized forms of scarring alopecia.

The incidence of human herpesvirus 6 infection in children with febrile convulsion admitted to the University Hospital, Kuala Lumpur

From October 1996 to March 1997, 31 children with febrile convulsions were admitted to the University Hospital, Kuala Lumpur. Human Herpesvirus 6 (HHV 6) was virologically and/or serologically confirmed to be the cause of the febrile episode in 5 of these children (16.1%). Age, sex and other associated clinical features (diarrhoea, cough, running nose and type of seizure) were not useful in differentiating cases of febrile convulsion due to HHV 6 from those of other aetiology. However, uvulo-palatoglossal junctional ulcers were noted in children in whom the cause of the seizure could be attributed to HHV 6 but not in the remaining cases in the study group. HHV 6 DNA was detected in peripheral blood mononuclear cells from all patients with febrile convulsions attributed to HHV6, and in patients shown serologically to have already been exposed to the virus by nested polymerase chain reaction amplification. Only genotype HHV 6B was detected from patients with seizure due to HHV 6 but both genotype 6A and 6B were detected in the remaining cases studied.

Hypercholesterolemia exacerbates transplant arteriosclerosis via increased neointimal smooth muscle cell accumulation: studies in apolipoprotein E knockout mice

BACKGROUND

Hypercholesterolemia is thought to be a significant risk factor for coronary vasculopathy in cardiac transplant recipients.

METHODS AND RESULTS

We examined the development of arteriosclerosis in mouse carotid artery loops allografted from B.10A(2R) (H-2h2) donors to normocholesterolemic C57BL/6J (H-2h) recipients and hypercholesterolemic C57BL/6J recipients in which the apolipoprotein (apo) E gene had been knocked out. Luminal occlusion and cross-sectional neointimal area were greater in arteries allografted into hypercholesterolemic recipients at 15 and 30 days after transplantation. We also measured cellular and extracellular matrix components of the neointima by computerized planimetry of the fractional areas subtended by smooth muscle cells (anti-alpha-actin stain), collagen (Masson's trichrome), lipid (oil red O), and leukocytes (anti-CD45). The neointimal area stained for smooth muscle cells was significantly greater in hypercholesterolemic recipients than in normocholesterolemic recipients at 15 and 30 days after allografting. Lipid contributed to neointimal area to a lesser degree, and there was no significant increase in the contribution of collagen or leukocytes.

CONCLUSIONS

Smooth muscle cell accumulation appears to be the principal contributor to the increase in neointimal area observed in arteries allografted into hypercholesterolemic mice.

The selectivity of MDL 74,721 in models of neurogenic versus vascular components of migraine

MDL 74,721 (R)-2-(N1,N1-dipropylamino)-8-methylaminosulfonylmethyl-1,2,3,4-te trahydronaphthalene, a sulfonamidotetralin, has been found to exhibit a 10,000-fold greater potency in neurogenic versus vascular models of migraine. Sumatriptan, a relatively pure 5-HT1D/5-HT1B receptor agonist, also showed higher potency versus neurogenic inflammation. However, for sumatriptan the potency difference (100-fold) in the two pathophysiological models was less pronounced than seen for MDL 74,721. The affinity profile of MDL 74,721 at 5-HT1 receptor subtypes may in part explain its ability to differentiate these two physiological responses. MDL 74,721 demonstrated nanomolar affinity for 5-HT1A (12.7 +/- 0.3 nM) and 5-HT1D (41.3 +/- 10.9 nM) but considerably lower affinity for 5-HT1B receptors (> 1000 nM). Serotonin-like activity was seen in in vitro functional assays including inhibition of forskolin-stimulated cAMP accumulation in human 5-HT1D receptor-transfected fibroblasts or eliciting vasoconstriction in isolated human pial arteries. The intrinsic activity (relative to 5 - HT[E(Amax)]) and affinity (pD2) for the human cerebrovascular 5-HT receptors were: 5-HT (100%, 7.51 +/- 0.09), sumatriptan (94%, 6.85 +/- 0.1) and MDL 74,721 (66%, 5.70 +/- 0.23). In anaesthetised cats, treatment with MDL 74,721 resulted in a dose-related reduction in the percentage of carotid flow going through the arteriovenous anastomoses to the lungs, with an ED50 of 0.3 mg/kg i.v., the same as sumatriptan. However, in the guinea-pig neurogenic model, MDL 74,721 inhibited plasma protein extravasation with an ED50 of 0.023 microg/kg compared to 2.5 microg/kg for sumatriptan. MDL 74,721 was also effective in this model (in rats) after oral administration. In conclusion, MDL 74,721 demonstrates a preclinical profile consistent with anti-migraine efficacy. Its marked preference for inhibiting neurogenic inflammation makes this compound a useful tool for assessing the relative contribution of this pathophysiological mechanism to the human disease state.

Epstein Barr virus associated hemophagocytic syndrome--a case report

Virus associated hemophagocytic syndrome (VAHS) are a heterogeneous group of disorders in which viral infection is associated with a proliferation of hemophagocytic histiocytes through the reticuloendothelial system. We report the case of a 21-year-old Korean man who presented to us with high fever, marked hepatosplenomegaly, severe hepatic dysfunction, coagulopathy, pancytopenia and marked panhypogammaglobulinemia. Bone marrow aspiration and biopsy showed histiocytes proliferation with active phagocytosis of red cells and neutrophils. Primary Epstein-Barr (EB) viral infection at presentation was confirmed by the presence of IgM antibody to viral capsid antigen (VCA) with absence of antibody to EB viral nuclear antigen (EBNA). A liver biopsy performed one month after the presentation showed erythrophagocytic histiocytes within the sinusoids. EB virus was demonstrated in the liver biopsy tissue by DNA PCR method, and EBER mRNA in situ hybridization.

'Swiss cheese' lymphangiectasia in a case of solitary morphea profunda

Reports of lymphangiectases that occur in lesions of morphea are rare. We describe a 24-year-old woman with a solitary morphea profunda associated with lymphangiectasia. Unlike previously reported cases, our case showed lymphatic dilatation resembling Swiss cheese and developed around a milium.

Progesterone inhibits arterial smooth muscle cell proliferation

Mortality from atherosclerotic cardiovascular disease is lower in premenopausal women than in age-matched men. It is also lower in postmenopausal women who take estrogens and progestins together rather than estrogens alone. Progesterone receptors were detected in human and rat aortic smooth muscle cells in vivo and in vitro (in subculture). We examined the effect of progesterone on proliferation of smooth muscle cells, important constituents of atherosclerotic plaques. Progesterone at physiologic levels inhibited DNA synthesis and proliferation in these cells in a dose-dependent manner, and pretreatment with the progesterone receptor antagonist RU486 blocked inhibition. Cyclin A and E messenger RNA levels decreased after progesterone treatment but those of cyclin B and D1 did not change. This cell cycle-dependent inhibition of arterial smooth muscle cell proliferation by progesterone may represent a mechanism for the hormone's protective effect against atherosclerosis.

Nevus spilus (speckled lentiginous nevus) associated with a nodular neurotized nevus

We report a case of nevus spilus with neurotized nevus studied by immunohistochemical methods using S-100, leu-6, glial fibrillary acid protein (GFAP), and myelin basic protein (MBP). Histologic findings of the speckled lesion showed irregular rete ridge elongation, increased epidermal melanocytes and melanin in the epidermis, and scattered nevus cell nests in the upper dermis, but showed neurotized nevus in the deep dermis, which has many features of neurofibroma. Diffuse expression of S-100 protein and MBP, focal staining with GFAP, and lack of staining with leu-7 were observed, Leu-7, positive only in neurofibromas and not in neurotized nevus, appears to be the more pertinent method for distinguishing neurotized nevus from neurofibroma.