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Biomedical subjects

J H Ryu

Publications and source records attributed to J H Ryu.

At least 91 records · Page 5Linked to original sources
PubMed1995

Cavitary pulmonary infarct in immunocompromised hosts.

Pulmonary disease in immunocompromised patients is common, but cavitary lung disease is less common and is usually associated with a fungal or mycobacterial infection. Pulmonary embolism is a noninfectious cause of a cavitary pulmonary process. Pulmonary embolism causes infarction in fewer than 15% of cases, and only about 5% of infarctions cavitate. Herein we describe two cases of cavitary infarcts in immunocompromised patients and review the clinical aspects of pulmonary infarcts and cavitation. Cavitary pulmonary infarction has been reported only rarely in immunocompromised patients. It is a dangerous but treatable pulmonary disease that must be considered in the differential diagnosis of immuno-compromised patients with lung disease.

Aged↗
PubMed1995

Histamine H1 receptor occupancy in human brains after single oral doses of histamine H1 antagonists measured by positron emission tomography.

1. Histamine H1 receptor occupancy in the human brain was measured in 20 healthy young men by positron emission tomography (PET) using [11C]-doxepin. 2. (+)-Chlorpheniramine, a selective and classical antihistamine, occupied 76.8 +/- 4.2% of the averaged values of available histamine H1 receptors in the frontal cortex after its administration in a single oral dose of 2 mg. Intravenous administration of 5 mg (+)-chlorpheniramine almost completely abolished the binding of [11C]-doxepin to H1 receptors (H1 receptor occupancy: 98.2 +/- 1.2%). 3. Terfenadine, a nonsedative antihistamine, occupied 17.2 +/- 14.2% of the available H1 receptors in the human frontal cortex after its administration in a single oral dose of 60 mg. 4. There was no correlation between H1 receptor occupancy by terfenadine and the plasma concentration of the active acid metabolite of terfenadine in each subject. 5. PET data on human brain were essentially compatible with those on H1 receptor occupancy in guinea-pig brain determined by in vivo binding techniques, although for the same H1 receptor occupancy the dose was less in human subjects than in guinea-pigs. 6. The PET studies demonstrated the usefulness of measuring H1 receptor occupancy with classical and second-generation antihistamines in human brain to estimate their unwanted side effects such as sedation and drowsiness quantitatively.

Administration, Oral↗
PubMed1995

Stationary organization of the actin cytoskeleton in Vallisneria: the role of stable microfilaments at the end walls.

In mesophyll cells of the aquatic angiosperm Vallisneria gigantea, bundles of microfilaments (MFs) serve as tracks for the rotational streaming of the cytoplasm, which occurs along the two longer side walls and the two shorter end walls. The stationary organization of these bundles has been shown to depend on the association of the bundles with the plasma membrane at the end walls. To identify the sites of such association, the effects of cytochalasin B (CB) on the configuration of the bundles of MFs were examined. In the case of the side walls, MFs were completely disrupted after treatment with CB at 100 micrograms/ml for 24 hours. By contrast, in the case of the end walls, a number of partially disrupted MFs remained even after 48 hours of treatment. After removal of CB, a completely normal arrangement of bundles of MFs was once again evident within 24 hours after a rather complicated process of reassembly. When reassembly had been completed, the direction of cytoplasmic streaming was reversed only in a small fraction of the treated cells, suggesting that bundles of MFs are anchored and stabilized at the end walls of each cell and that the polarity of reorganized bundles and, therefore, the direction of the cytoplasmic streaming is determined in a manner that depends on the original polarity of MFs that remained in spite of the disruptive action of CB. By contrast, the direction of reinitiated cytoplasmic streaming was reversed in 50% of cells in which the bundles of MFs had been completely disrupted by exogenously applied trypsin prior treatment with CB.(ABSTRACT TRUNCATED AT 250 WORDS)

Actin Cytoskeleton↗
PubMed1995

Pulmonary tuberous sclerosis.

We describe the clinical presentation, pulmonary function tests, chest radiograph, and computed tomography findings, response to hormonal treatment, and duration of survival of nine patients with pulmonary involvement in tuberous sclerosis complex with follow-up over an average of 17 years (range, 1 to 35 years) since diagnosis. All patients were female, and the average age at onset of symptoms was 16 years (range, 3 months to 39 years); pulmonary symptoms did not develop until an average age of 33 years (range, 22 to 46 years). There was an average delay of 8 years before the correct diagnosis was made. The most common presenting clinical features were seizures, pneumothorax, bleeding into a renal angiomyolipoma, dyspnea, and typical skin changes. Pulmonary function tests commonly demonstrated obstruction to airflow and reduced single-breath diffusing capacity. Chest radiograph and computed tomography characteristically demonstrated diffuse interstitial infiltrates with cystic changes. Two asymptomatic patients with mild pulmonary involvement have remained in stable condition without hormonal therapy. The remaining seven patients had moderate to severe airflow obstruction; of these, five underwent hormonal therapy. Three patients had a clinical response to treatment. Two patients who did not receive hormonal treatment died of progressive respiratory failure. Most patients with pulmonary involvement in tuberous sclerosis have a slowly declining clinical course. Although the available data are limited, they suggest that a trial of hormonal therapy is recommended both for symptomatic patients and for those with declining pulmonary function. Tuberous sclerosis complex should be suspected in all patients with the diagnosis of lymphangioleiomyomatosis.

Adult↗
PubMed1995

Idiopathic perilymphatic fistulae: a temporal bone histopathological study. Clinical, surgical and histopathological correlations.

The temporal bone histopathological findings herein reported are the first to be from a patient who had, during life, the diagnosis of idiopathic perilymphatic fistulae. The patient received surgical treatment followed by rapid improvement of his vestibular symptoms. These specimens histopathologically demonstrate the patencies of the labyrinth capsule that were diagnosed (predicted) clinically during life, the qualities of the membranous labyrinth in both the operated and unoperated ears, and the elements of the surgical repair. Notably there is no evidence of endolymphatic hydrops. The diagnostic features which allowed this patient with fluctuating hearing loss, episodic vertigo, and tinnitus to be distinguished from a patient with Meniere's syndrome are discussed as are the implications regarding future and past studies of vestibular and cochlear disorders.

Aged↗
PubMed1995

Clinical characteristics of fatal pulmonary embolism in a referral hospital.

OBJECTIVE: To determine the clinical characteristics of hospitalized patients who died of pulmonary embolism, confirmed by evaluative autopsy. DESIGN: We retrospectively analyzed a series of autopsy cases of pulmonary embolism at a tertiary-care center for the period Jan. 1, 1985, through Dec. 31, 1989. MATERIAL AND METHODS: The medical and autopsy records of all hospitalized patients with autopsy-proven fatal pulmonary embolism were reviewed. Cases of tumor emboli, fat emboli, and contributory-only thromboembolic disease were excluded from the study. Specific symptoms and signs, diagnostic studies, and prophylactic measures were noted. RESULTS: Among 2,427 autopsies performed during the 5-year study period, death in 92 (3.8%) was clinically and pathologically judged to be caused by pulmonary embolism. No risk factors were noted in only 11 patients (12%). Prophylaxis against thromboembolism was used in 46%. Classic symptoms were often absent: dyspnea was present in only 59%, chest pain in only 17%, and hemoptysis in 3%. Pulmonary embolism was considered in 49% of the 92 patients and was correctly assigned as the cause of death on the death certificate or in the medical records in 32%. Testing for venous thromboembolic disease was performed in 22%. Comorbidity was present in most patients: 54% had guarded or poor prognoses independent of pulmonary embolism. CONCLUSION: The usual signs and symptoms associated with pulmonary embolism did not adequately identify most of our patients who died of pulmonary embolism. The reasons included the absence of these signs and symptoms, inability to communicate (for example, sedated or comatose patient), sudden death from acute massive pulmonary embolism, and presence of comorbid factors.

Adult↗
PubMed1995

High resolution two-dimensional electrophoresis: technique and potential applicability to the study of inner ear disease.

Technologic progress in two-dimensional polyacrylamide gel electrophoresis (2-D Page), in combination with immunoblotting, amino acid sequencing, and computer-assisted image analysis, allowed establishment of human body fluid and tissue "reference maps," which in turn enabled meaningful comparison of data from various clinical and research centers. Altered protein profiles have been observed in plasma/serum, cerebrospinal fluid, urine, and other body fluids in numerous systemic or localized pathologic entities. Human perilymph, obtained during ear surgery or post mortem, exhibits a protein profile differing from plasma in several ways. Most interesting are the extremely high levels of high density lipoprotein-associated proteins, a group of proteins thought to play a role in atherosclerosis, nerve damage/regeneration, chronic inflammation, and Alzheimer's disease, among others. A technique is described for collection and analysis of human perilymph, using a state-of-the-art standardized 2-D Page technique. It is expected that, as in other body fluids, disease-specific protein patterns will be identified. With the possible exception of presumed perilymphatic fistula, it is not envisioned that analysis of perilymph will be used for diagnostic purposes but rather as an aid for the elucidation of the mechanisms underlying inner ear disease, whether localized or as part of systemic alterations.

Adult↗
PubMed1995

Positron emission tomographic study of central histamine H1-receptor occupancy in human subjects treated with epinastine, a second-generation antihistamine.

Histamine H1-receptor occupancy in the human brain was measured in healthy young volunteers by positron emission tomography (PET) using [11C]doxepin. d-Chlorpheniramine, a selective and classical antihistamine, occupied 76.8 +/- 4.2% of the averaged values of available histamine H1 receptors in the frontal cortex after its administration in a single oral dose of 2 mg. Epinastine, a non-sedative antihistamine, occupied 13.2 +/- 18.5% of the available H1 receptors in the human frontal cortex after its administration in a single oral dose of 20 mg. There was significant correlation between H1 receptor occupancy by epinastine and its plasma concentration in each subject. PET data on the human brain were essentially compatible with those on H1-receptor occupancy in the guinea pig brain as determined by an in vivo binding technique, although for the same H1-receptor occupancy, the dose was less in humans than in guinea pigs. Our PET studies demonstrated that receptor occupancy by a second-generation H1 antagonist, epinastine, was less than 20% of the total H1 receptors, and that the low receptor occupancy was closely related to the low incidence of central side effects.

Adult↗
PubMed1994

Marked increase in histamine H3 receptors in the striatum and substantia nigra after 6-hydroxydopamine-induced denervation of dopaminergic neurons: an autoradiographic study.

The bindings of [3H](R) alpha-methylhistamine to histamine H3 receptors were investigated in rat brain following intranigral treatment with 6-hydroxydopamine (6-OHDA) by quantitative receptor autoradiography. The levels of [3H](R) alpha-methylhistamine binding sites in the denervated striatum (dorsomedial and dorsolateral) and substantia nigra were significantly higher than those in the contralateral side 21 days after nigral lesions. Saturation kinetic analysis revealed that the maximum binding capacities were up-regulated to about 1.7- and 1.2-fold those in the contralateral substantia nigra and striatum, respectively. These results strongly suggest that H3 receptors in the striatum and substantia nigra are influenced by tonic dopaminergic inputs.

Animals↗
PubMed1994

Marked increase in [3H](R) alpha-methylhistamine binding in the superior colliculus of visually deprived rats after unilateral enucleation.

The binding of [3H](R)alpha-methylhistamine to histamine H3-receptors in visual structures of unilaterally enucleated rats was examined by quantitative autoradiography to clarify the involvement of histamine neurons in the visual system. [3H](R)alpha-Methylhistamine binding in the visually deprived superior colliculus, contralateral to the enucleated eye, was significantly increased 5, 15, 30 and 45 days after unilateral enucleation. Slight time-dependent increases in ligand binding were observed in the visual cortex, but the change was significant only 45 days after unilateral enucleation. Unilateral enucleation had no significant effect in the dorsal lateral geniculate nucleus at any time after enucleation. Continuous injection of (S)-alpha-fluoromethylhistidine, a specific inhibitor of L-histidine decarboxylase, attenuated the effect of unilateral enucleation in the superior colliculus. These results suggest that retinal deafferentation induced an increase in histamine H3-receptor binding sites, probably by selective adjustment of histamine neurons in response to unilateral enucleation.

Animals↗
PubMed1994

Heterogeneous distributions of histamine H3, dopamine D1 and D2 receptors in rat brain.

The changes of the histamine H3 and dopamine D1 or D2 receptor binding sites induced by quinolinic acid treatment were studied in order to discriminate the comparative distribution. This treatment resulted in similar decreases in histamine H3 and dopamine D1 receptor binding sites in the striatum and ipsilateral substantia nigra. Dopamine D2 receptor binding sites were relatively well conserved, whereas H3 receptors decreased considerably. These results suggest that histamine H3 and dopamine D1 receptor binding sites are localized on the striatonigral projection neurones which are together sensitive to quinolinic acid, and that the distributional compartment of dopamine D2 receptor binding sites is quite different from those of histamine H3 and dopamine D1 receptors.

Animals↗
PubMed1994

Binding characteristics of a histamine H3-receptor antagonist, [3H]S-methylthioperamide: comparison with [3H](R)alpha-methylhistamine binding to rat tissues.

The release and synthesis of neuronal histamine are regulated by histaminergic autoreceptors named as histamine H3 receptors. The development of radiolabeled histamine H3 antagonists is needed to characterize the binding of antagonists to these receptors. Here we describe the binding characteristics of a new histamine H3-receptor antagonist, [3H]S-methylthioperamide (SMT), to rat tissues, and compare its binding with that of [3H](R)alpha-methylhistamine ((R)alpha MH), a selective histamine H3-receptor agonist. The binding of [3H]SMT to the membranes of rat forebrain was found to be stereoselective, saturable, reversible and temperature-dependent. Saturation binding experiments indicated a single class of high affinity sites for [3H]SMT in forebrain membranes (KD = 2.1 nM, Bmax = 24.3 pmol/g of tissue at 4 degrees C). The Bmax was approximately 3 times that of [3H](R)alpha MH binding to rat forebrain membranes (KD = 2.5 nM, Bmax = 7.3 pmol/g of tissue at 25 degrees C). Autoradiographic images of [3H]SMT binding in the brain were essentially the same as those of [3H](R)alpha MH. [3H]SMT also bound appreciably to peripheral tissues (the liver, adrenal, stomach, ileum, kidney, lung and bladder), whereas the [3H](R)alpha MH bindings to these peripheral tissues were negligible. These results indicate that [3H]SMT binds to H3 receptors primarily in the central nervous system, and that it also has high affinity toward non-H3 receptors, probably hemoproteins, in peripheral tissues.

Animals↗
PubMed1993

Cloning of a cDNA encoding bovine mitochondrial NADP(+)-specific isocitrate dehydrogenase and structural comparison with its isoenzymes from different species.

Mitochondrial NADP(+)-specific isocitrate dehydrogenase (IDP) was co-purified with the pyruvate dehydrogenase complex from bovine kidney mitochondria. The determination of its N-terminal 16-amino-acid sequence revealed that it is highly similar to the IDP from yeast. A cDNA clone (1.8 kb long) encoding this protein was isolated from a bovine kidney lambda gt11 cDNA library using a synthetic oligodeoxynucleotide. The deduced protein sequence of this cDNA clone rendered a precursor protein of 452 amino-acid residues (50,830 Da) and a mature protein of 413 amino-acid residues (46,519 Da). It is 100% identical to the internal tryptic peptide sequences of the autologous form from pig heart and 62% similar to that from yeast. However, it shares little similarity with the mitochondrial NAD(+)-specific isoenzyme from yeast. Structural analyses of the deduced proteins of IDP isoenzymes from different species indicated that similarity exists in certain regions, which may represent the common domains for the active sites or coenzyme-binding sites. In Northern-blot analysis, one species of mRNA (about 2.2 kb for both bovine and human) was hybridized with a 32P-labelled cDNA probe. Southern-blot analysis of genomic DNAs verified simple patterns of hybridization with this cDNA. These results strongly indicate that the mitochondrial IDP may be derived from a single gene family which does not appear to be closely related to that of the NAD(+)-specific isoenzyme.

Amino Acid Sequence↗
PubMed1993

Renal angiomyolipoma in association with pulmonary lymphangioleiomyomatosis: forme fruste of tuberous sclerosis?

From 1976 to 1989, 27 patients with pulmonary lymphangioleiomyomatosis were seen at our institution. Twenty-five had no signs or symptoms of tuberous sclerosis; 21 of these had abdominal imaging or surgical exploration to make the diagnosis of renal angiomyolipoma in seven patients, all female. Three presented with symptoms secondary to renal disease, three with pulmonary manifestations, and one with both. Renal disease was bilateral in four patients; four patients underwent nephrectomy and two tumors were embolized. All patients experienced spontaneous pneumothoraces during the course of their disease. There was one respiratory death. It is our belief that any patient presenting with angiomyolipoma and a history of pulmonary problems should be evaluated for pulmonary lymphangioleiomyomatosis with a limited computed tomography scan of the chest at the time of abdominal imaging. The surgical treatment of angiomyolipoma when associated with lymphangioleiomyomatosis is predicated on the ability to adequately manage the complicating lung disease perioperatively.

Adult↗
PubMed1993

Angiosarcoma in the lung.

Angiosarcoma involving the lung is a rare disorder and its clinical features are not well known. We conducted a retrospective analysis of 15 patients seen at our institution from 1950 to 1990 in an attempt to better characterize the spectrum of clinical and radiographic findings of angiosarcoma in the lung. No documented case of primary angiosarcoma of the lung was seen. The diagnosis of metastatic angiosarcoma to the lung was made antemortem in 12 of 15 cases, either by lung biopsy specimen (5 patients), biopsy evidence of metastatic disease elsewhere with abnormal chest radiograph (4 patients), or a compatible clinical picture in a patient with previously documented angiosarcoma arising in an extrapulmonary site (3 patients). The median age at the time of diagnosis was 45 years with the most common presenting symptom being hemoptysis (7 of 15 patients). Other presenting complaints included weight loss (6 of 15), cough (4 of 15), and chest pain (4 of 15) occurring 6 weeks to 1 year prior to diagnosis. Chest radiographs frequently disclosed multiple pulmonary nodules (11 of 15). Primary origins of the angiosarcoma most commonly included the heart and breast. Metastatic sites other than the lung included the pericardium, liver, spleen, kidney, adrenal gland, bone, and brain. The prognosis is generally poor, with our study population surviving an average of 9 months after diagnosis.

Adolescent↗
PubMed1993

Bronchiolitis obliterans organizing pneumonia caused by Plasmodium vivax malaria.

A 64-year-old woman developed a relapse of Plasmodium vivax malaria followed by a rapidly progressive diffuse patchy pulmonary process. Open lung biopsy specimen showed bronchiolitis obliterans organizing pneumonia (BOOP). After corticosteroid therapy was initiated, there was both clinical and radiographic improvement. This is believed to be the first reported association of BOOP with malaria.

Biopsy↗