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Biomedical subjects

S Go

Publications and source records attributed to S Go.

At least 19 recordsLinked to original sources

Deep vein thrombosis in a tetraparesic patient with mental retardation: case report and review of the literature.

OBJECTIVE: To report a case of deep vein thrombosis (DVT) in a tetraparesic patient, a member of a population in which DVT is reportedly rare. CASE REPORT: A 36-year old tetraparesic resident of a developmental centre suddenly developed swelling of one leg. Her plasma D-dimer level was 751 (normal<500) ng ml-1. A Doppler ultrasound revealed femoral vein thrombosis. She usually spent 10-12 hours daily in a chair. For menstrual problems, she had received oral contraceptives (OC) for 23 months. She had no other genetic or acquired predisposition to DVT. She was anti-coagulated for 6 months and the OC was discontinued. She recovered without complications. Her DVT was probably caused by her immobility, prolonged sitting and OC. CONCLUSION: DVT may develop in tetraparesic patients if they are exposed to additional prothrombotic factors. OC should be prescribed cautiously to such people. Relevant literature, prevention and treatment are discussed.

Adult↗

A homozygous missense mutation in the tyrosine E kinase domain of the RET proto-oncogene in an infant with total intestinal aganglionosis.

Germline mutations of the RET proto-oncogene (RET), its ligand glial cell-derived neurotrophic factor (GDNF), and neurturin (NTN) gene have been reported in patients with Hirschsprung's disease. A targeted mutation in the tyrosine kinase domain of RET produced total intestinal aganglionosis and renal agenesis in homozygous transgenic mice. Here we describe a homozygous mutation of the human gene for the RET tyrosine kinase domain that was present in a male neonate with total intestinal aganglionosis. Gut wall biopsy specimens from the stomach to the anorectum showed no ganglion cells. No urinary tract abnormalities were detected. Genomic DNAs were isolated from peripheral blood lymphocytes of the infant and his parents. DNA sequences of all the RET/GDNF/NTN coding regions were determined using a direct DyeDeoxy Terminator Cycle method. A homozygous missense mutation (CGG-to-TGG) at RET codon 969 was identified in this patient, which resulted in an amino acid change from arginine to tryptophan. No germline RET/GDNF/NTN mutations were found in his parents. In this case, the homozygous RET mutation seemed to cause a critical alteration of the Ret tyrosine kinase activity, which resulted in total intestinal aganglionosis but not renal agenesis. Discrepancies in phenotypic expression between humans and mice suggest differing threshold values for RET signal transduction in species or organs.

Drosophila Proteins↗

Structural studies of soluble oligomers of the Alzheimer beta-amyloid peptide.

Recent studies have suggested that non-fibrillar soluble forms of Abeta peptides possess neurotoxic properties and may therefore play a role in the molecular pathogenesis of Alzheimer's disease. We have identified solution conditions under which two types of soluble oligomers of Abeta40 could be trapped and stabilized for an extended period of time. The first type of oligomers comprises a mixture of dimers/tetramers which are stable at neutral pH and low micromolar concentration, for a period of at least four weeks. The second type of oligomer comprises a narrow distribution of particles that are spherical when examined by electron microscopy and atomic force microscopy. The number average molecular mass of this distribution of particles is 0.94 MDa, and they are are stable at pH 3 for at least four weeks. Circular dichroism studies indicate that the dimers/tetramers possess irregular secondary structure that is not alpha-helix or beta-structure, while the 0.94 MDa particles contain beta-structure. Fluorescence resonance energy transfer experiments indicate that Abeta40 moieties in amyloid fibrils or protofibrils are more similar in structure to those in the 0.94 MDa particles than those in the dimers/tetramers. These findings indicate that soluble oligomeric forms of Abeta peptides can be trapped for extended periods of time, enabling their study by high resolution techniques that would not otherwise be possible.

Alzheimer Disease↗

Ultrasonographic detection of intrauterine intussusception resulting in ileal atresia complicated by meconium peritonitis.

A neonate with ileal atresia (IA) complicated by meconium peritonitis (MP) whose prenatal ultrasonography (US) detected an intrauterine intussusception (IUI) is reported. Fetal ascites, dilated bowel loops, and abdominal calcifications were identified on serial US from 25 weeks of gestation. Intestinal loops with high echogenecity and a "target-like" appearance suggestive of IUI were detected in the right lower quadrant. The 2,680-g male was delivered vaginally at term and underwent a laparotomy. Fibrous adhesions and small calcifications were scattered throughout the peritoneal cavity. IA (interrupted type) was confirmed 17.0 cm cranial to the ileocecal valve (ICV). An ileo-ileal intussusception was also found between 16.5 cm and 9.0 cm cranial to the ICV. Partial resection of the ileum and an ileo-ileal anastomosis was performed. The postoperative course was uneventful. In this case, the pathological process of IUI resulting in IA and MP was demonstrated sonographically by identifying the "target-like" appearance in the fetus.

Adult↗

Arteriovenous malformation of the penis in an infant.

Arteriovenous malformations (AVMs) are common benign lesions in infancy, although they are rare in the genitourinary region. The authors report on a 2-year-old boy with a penile AVM. At presentation, there was venous dilatation and tortuosity of the prepuce without ulceration, which had been recognized at 1 year of age. Left internal iliac arteriography showed early venous filling leading to the diagnosis of AVM. Surgical excision was performed at age 2. The postoperative course was uneventful. At the 6-month follow-up, there was no evidence of recurrence. This is the first report of a penile AVM that was successfully treated by surgical excision.

Arteriovenous Malformations↗

Equilibrium folding intermediates of a Greek key beta-barrel protein.

Protein S is a calcium-binding protein comprising two Greek key beta-barrel domains. We have used NMR and optical spectroscopies to show that, in the absence of calcium, the N-terminal domain of protein S forms two equilibrium folding intermediates that are in slow exchange. The intermediates arise from differential calcium-dependent folding of subdomains which are not contiguous along the polypeptide chain. The structures of these intermediates are incompatible with several previously proposed folding mechanisms for Greek key beta-barrel domains. We proposed a different mechanism that involves multiple nucleation sites for folding and sequential acquisition of native long-range interactions.

Calcium↗

Hemopexin from four species inhibits the association of heme with cultured hepatoma cells or primary rat hepatocytes exhibiting a small number of species specific hemopexin receptors.

Hemopexin (Hx) binds heme with a very high affinity (Kd<0.1 pmol/L). It has been implicated as a major vehicle for the transport of heme into liver cells, involving a receptor-mediated recycling mechanism. However, previous studies indicated that heme is not taken up by cultured embryonic chick or adult rat hepatocytes by such a mechanism, because heme added as heme hemopexin failed to affect heme-responsive activities of 5-aminolevulinic acid synthase and heme oxygenase. Here, we investigated the importance of hemopexin in hepatic heme uptake in cultured rat hepatocytes and human HepG2 hepatoma cells, and determined the number and species specificity of hemopexin receptors on the rat hepatocytes. We also tested whether there is a difference between heterologous and homologous hemopexins. We found the following: 1) heme is inhibited from associating with hepatocytes by apo hemopexins from rat, human, rabbit, and chicken; 2) heme readily associates with hepatocytes when heme hemopexin preparations are added in which the ratio of heme to hemopexin exceeds 1.0; 3) heme induces heme oxygenase mRNA in rat hepatocytes and this induction is prevented by excess hemopexin; and 4) rat hepatocytes exhibit only about 2,000 hemopexin receptors per cell when using rat hemopexin, and none when using hemopexin of rabbit and human. We conclude that hemopexin plays a limited role in heme uptake by cultured hepatocytes and hepatoma cells, and that heme which exceeds the hemopexin binding capacity is taken up directly from heme-albumin.

Animals↗

Fatal pulmonary hypertension in a patient with mixed connective tissue disease: report of an autopsy case.

A 34-yr-old woman with mixed connective tissue disease (MCTD) who died of heart failure due to pulmonary hypertension (PH) is reported. She showed various symptoms and signs over the previous 8 yr, including lymphadenopathy, Raynaud's phenomenon, polyarthralgia, sclerodactylia, esophageal disturbance, PH, Sjögren's syndrome and renal tubular acidosis. Autopsy findings revealed severe intimal proliferation with marked luminal narrowing of the small arteries in the lung. Echocardiographic and mechanocardiographic methods were very useful for assessment of the degree of right ventricular dysfunction associated with PH on the early stage of MCTD.

Adult↗

Champ Camp: the Colorado Children's Asthma Camp experience.

To encourage children with asthma to enjoy outdoor activities without physical or psychosocial impairment, children's asthma camps are established throughout the country sponsored by organizations including local and state allergy societies. We wish to describe our Colorado "Champ Camp" experience as a model and reference for future similar efforts and to encourage networking by medical leadership for information sharing and guidelines development nationally. Statistics from parents' satisfaction surveys over 8 years demonstrate a positive influence on attitudes toward asthma and confidence to enter activities and sports with children without asthma.

Asthma↗

Cerebral and myocardial infarction induced by nonbacterial thrombotic endocarditis in a patient with ovarian cancer: report of a case.

A 40-year-old woman was admitted to our hospital because of left hemiplegia. She was affected with myocardial infarction and cerebral infarction. Echocardiogram revealed that the aortic and mitral valves had thick and uneven echoes suggesting vegetations. Judging from the finding that repeated blood cultures were negative, we had considered in her lifetime that myocardial and cerebral infarctions were due to embolization associated with nonbacterial thrombotic endocarditis (NBTE). At autopsy, histological diagnosis was made as ovarian cancer with disseminated intravascular coagulation. From the clinical course and the histological findings, we diagnosed this patient as NBTE.

Adult↗

Autopsy findings in two patients with homozygous familial hypercholesterolemia. Special references to apolipoprotein B localization and internalization defect of low density lipoprotein.

We have experienced two autopsy cases of familial hypercholesterolemia of type IIa homozygote, one was a 21-year-old female with a defect in the internalization of low density lipoprotein which is thought to be the first autopsy report in the world, and the other was a 31-year-old male with a receptor negative for low density lipoprotein. Autopsy findings, in addition to marked skin xanthomatosis, disclosed reversed distribution of the aortic atherosclerosis, diffuse atherosclerotic narrowing of coronary arteries which led to myocardial necrosis, xanthomatous aortic and mitral valve, and much less severity of cerebral arteries rather than that of aorto-coronary atherosclerosis. We have examined the apolipoprotein B accumulation on these aortas, coronary arteries, and cardiac valves, which showed better correlation between apolipoprotein B deposit areas and preferential accumulation of Alcian blue positive areas suggested to contain sulfate glycosaminoglycan, and documented very rare localization of renal and osseous xanthomas in a patient with internalization defect of low density lipoprotein.

Adult↗

Effects of degranulation of mast cells on proliferation of mesenchymal cells in the mesentery of mice.

A mast-cell activator, compound 48/80, causes proliferation of mesenchymal cells in the mesentery of rats. Its effect on W/Wv mice deficient in mast cells was tested to determine whether the proliferation is mediated in the degranulation of mast cells. Incorporation of [3H]thymidine into mesenchymal cells in the mesentery of these mice with or without compound 48/80 was very small compared to their normal litter mates. However, bone marrow transplantation markedly enhanced the effect of compound 48/80, and resulted in an incorporation of [3H]thymidine almost comparable to that observed in normal mice. Our results provide evidence that mesenchymal cell proliferation is caused by a product secreted by mast cells when stimulated by compound 48/80.

Animals↗