Biomedical subjects

T Uchida

Publications and source records attributed to T Uchida.

At least 307 records · Page 17Linked to original sources

PubMed1997

Hyaluronic acid inhibits fetal platelet function: implications in scarless healing.

Platelets are important for the initiation of inflammation in adults, but the role of fetal platelets in fetal wound healing is unclear because fetal dermal wounds heal with a minimal inflammatory response and lack of excessive scarring. Because fetal tissue is abundant in glycosaminoglycans (GAGs), predominantly hyaluronic acid (HA), this study was designed to test the hypothesis that HA inhibits the reactivity of platelets and thus contributes to the minimal scarring characteristic of fetal tissue repair. Platelets were isolated from 10 fetal pigs at day 80 of gestation (term, 115 days) and exposed to 0.5 mg/mL of arachidonic acid, an agent shown in prior studies to evoke maximal aggregation and degranulation of fetal platelets. The ability of HA at 0.1 and 0.5 mg/mL to inhibit this response was determined. The presence of HA resulted in a dose-dependent reduction in platelet aggregation at 180 seconds (control, 99.7 +/- 0.3%; HA [0.1 mg/mL] 91.7 +/- 3.8%; and HA [0.5 mg/mL] 48.5 +/- 9.0%; P < .005 v control). The onset of aggregation was also significantly delayed by 0.5 mg/mL of HA (13.5 +/- 2.5 seconds) compared to control (2.9 +/- 0.7 seconds), P < .05. No significant diminution of platelet aggregation could be achieved by the addition of other GAGs at similar concentrations. HA also significantly impaired the release of platelet-derived growth factor (PDGF)-AB from fetal platelets. The authors conclude that HA, the predominant GAG in fetal dermal matrix, inhibits platelet aggregation and cytokine release. This inhibition of platelet aggregation and resultant inflammatory response may explain, in part, the minimal inflammation and scarless healing characteristic of fetal dermal repair.

Analysis of Variance↗

PubMed1997

Hemodynamic effects of isovolemic hemodilution during descending thoracic aortic cross clamping and lower torso reperfusion.

BACKGROUND: Isovolemic hemodilution has been suggested for blood conservation and to improve hemodynamic tolerance to abdominal aortic cross clamping. However, the hemodynamic effects of hemodilution during descending thoracic aortic cross clamping (DAC) have not been established. We evaluated them in anesthetized swine. METHODS: Hemodilution (n = 7) was produced by the isovolemic exchange of blood for 6% hetastarch to a target hematocrit of 20%. Hematocrit in control pigs (n = 7) remained at 30%. DAC was performed at the T9 level for 45 minutes. During a 60-minute reperfusion period, control pigs were infused with lactated Ringer's solution; shed blood was returned to hemodilution pigs, followed by lactated Ringer's. If hypotension occurred despite left atrial pressure of 10 mm Hg or greater, boluses of phenylephrine were given to keep mean arterial pressure above 60 mm Hg. RESULTS: Hemodilution caused a marked reduction in hematocrit and in global oxygen delivery (DO2). DAC produced a significant increase in proximal arterial pressure, cardiac index, and DO2 and oxygen consumption (VO2) was markedly reduced in both groups. A significant increase in systemic vascular resistance during DAC occurred only in control pigs. After reperfusion, vascular resistance was significantly lower than baseline in hemodilution pigs, requiring a sixfold greater dose of phenylephrine to avoid hypotension. A lower global DO2 and supply-limited VO2 were also observed in hemodilution pigs. CONCLUSIONS: Isovolemic hemodilution maintains hemodynamic stability during DAC. During lower torso reperfusion, however, hemodilution caused hemodynamic instability, decreased global DO2, and limited VO2, which may offset its potential benefits.

Animals↗

PubMed1997

AE0047-mediated calcium channel blocking in vascular smooth muscles.

1. This experiment was designed to pharmacologically characterize a novel calcium channel blocker, AE0047. 2. After 1-hr treatment with each drug (10(-6) M), K(+)-induced contraction in rat aortic strip was clearly depressed by nifedipine and manidipine and slightly depressed by AE0047. After a wash out of the preparation in drug-free medium, the inhibition of K(+)-induced contraction by nifedipine or manidipine was abolished or unchanged, respectively. In contrast, AE0047-produced inhibition was reinforced with time after removal of the drug. 3. A cell membrane depolarization-induced 45Ca uptake into tissue was depressed completely by nifedipine, but, if it was washed out, merely 20% inhibition of control remained. AE0047-produced inhibition became prominent after drug removal. Manidipine did not have the same inhibitory effect after wash out. 4. A receptor-binding study indicated that affinity of AE0047 and manidipine for the dihydropyridine-sensitive Ca channel receptor was lower than that of nifedipine. AE0047, unlike nifedipine and manidipine, inhibited [3H]PN200-110 binding more strongly when a 4-hr preincubation was used than without extended incubation. 5. The drug molecule of AE0047 was highly partitioned into the lipid bilayer of the synaptosome in canine cerebral cortices. In the synaptic membrane and liposomes, both prepared from canine cerebral cortices, the respective partition coefficients of the drug were 6997 +/- 2309 and 422 +/- 28 against 1395 +/- 161 and 24 +/- 2 of nitrendipine. 6. AE0047 showed slower onset of inhibition against K(+)-induced contraction and enhanced Ca influx compared with manidipine and nifedipine. These results may suggest that AE0047 requires a long period of time to occupy the dihydropyridine-sensitive sites within the Ca channel, which was detected by decreased specific [3H]PN200-110 binding, and to inhibit K(+)-induced Ca influx into rat aorta.

Animals↗

PubMed1997

Pharmacokinetics of recombinant human interleukin-11 (rhIL-11) in healthy male subjects.

AIMS: To study the pharmacokinetics of recombinant human interleukin-11 (rhIL-11) in healthy male volunteers following subcutaneous (s.c.) and intravenous (i.v.) administration. METHODS: RhIL-11 was infused intravenously at 10-50 micrograms kg-1 for 1 or 3 h, or administered subcutaneously at 3-50 micrograms kg-1 to volunteers. RhIL-11 was also administered at 3 micrograms kg-1 s.c. once daily for 7 days. Plasma and urinary concentrations were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: RhIL-11 showed linear pharmacokinetics after both intravenous infusion and s.c. administration. Comparison of t1/2 and MRT values after i.v. administration with those after s.c. administration indicated that rhIL-11 pharmacokinetics after s.c. administration were absorption rate-limited. Bioavailability after s.c. administration was about 65%. Since RhIL-11 was not detected in urine after a single 50 micrograms kg-1 s.c. dose, rhIL-11 was considered to be eliminated by metabolism. There was no significant change in the pharmacokinetic profile of rhIL-11 following repeated s.c. administration. CONCLUSIONS: RhIL-11 demonstrated linear pharmacokinetics at these dose ranges after single and repeated s.c. administration or constant-rate i.v. infusion in healthy volunteers.

Adolescent↗

PubMed1997

Induction of cyclooxygenase 2 in gastric mucosal lesions and its inhibition by the specific antagonist delays healing in mice.

BACKGROUND & AIMS: The role of two forms of cyclooxygenase (COX-1 and COX-2) in gastric mucosal lesions is not well understood. The regulation of both forms of COX and the effect of COX-2 on the repair process of gastric mucosal lesions in mice were investigated. METHODS: Gastric mucosal erosions and ulcers were induced experimentally in mice. The level of COX messenger RNA (mRNA) was determined by reverse-transcription polymerase chain reaction. COX proteins were detected by Western blot analysis, and COX activity was determined in the presence or absence of NS-398, a specific COX-2 antagonist. The effects of long-term administration of NS-398 on gastric ulcers were examined. RESULTS: COX-2 mRNA levels were not detected in control conditions but were high during the acute stages of gastric erosions and ulcers. COX-2 protein was detected 5 days after ulcer induction but not in control mice. Gastric ulceration was not associated with a change in COX-1 mRNA and protein levels. Administration of NS-398 to mice with ulcers at acute stages impaired the healing of ulcers. CONCLUSIONS: High levels of COX-2 mRNA and protein during the acute stages of gastric mucosal lesions may be involved in the repair process of these lesions in mice.

Acetic Acid↗

PubMed1997

Differential stimulation requirements for IL-12 production among clones of macrophage hybridomas.

We have previously established cloned macrophage hybridomas by somatic cell fusion of the macrophage tumor P388D1 of DBA/2 (H-2d) origin with splenic adherent cells of CKB mice (H-2k). Several cloned lines displayed the serologic and functional characteristics of macrophages. In this study, we evaluated the ability of these hybridomas to produce IL-12 after combined stimulation with IFN-gamma and lipopolysaccharide (LPS). The patterns of IL-12 production by these cloned macrophages fell into three groups. The first group produced IL-12 on stimulation with LPS in combination with IFN-gamma pretreatment, the second group produced IL-12 on stimulation with LPS regardless of the pretreatment with IFN-gamma, and the third group did not produce IL-12 at all on stimulation with IFN-gamma and LPS. None of the macrophage clones tested produced IL-12 constitutively. The results correlated well with IL-12 p40 mRNA expression in those macrophages as detected by RT-PCR. These results suggest the differential stimulation requirements for IL-12 production among macrophages at a clonal level.

Animals↗

PubMed1997

L-arginine and superoxide dismutase prevent or reverse cerebral hypoperfusion after fluid-percussion traumatic brain injury.

To determine whether treatment with L-arginine or superoxide dismutase (SOD) would prove effective in reducing cerebral hypoperfusion after traumatic brain injury (TBI), we measured cerebral blood flow (CBF) using laser Doppler flowmetry (LDF) in rats treated before or after moderate (2.2 atm) fluid-percussion (FP) TBI. Rats were anesthetized with isoflurane and prepared for midline FP TBI and then for LDF by thinning the calvaria using an air-cooled drill. Rats were then randomly assigned to receive sham injury, sham injury plus L-arginine (100 mg/kg, 5 min after sham TBI), TBI plus 0.9% NaCl, TBI plus L-arginine (100 mg/kg, 5 min post-TBI), TBI plus SOD (24,000 U/kg pre-TBI + 1600 units/kg/min for 15 min after TBI), or TBI plus SOD and L-arginine. A second group of rats received TBI plus saline, L-, or D-arginine (100 mg/kg, 5 min after-TBI). After treatment and TBI or sham injury, CBF was measured continuously using LDF for 2 h and CBF was expressed as a percent of the preinjury baseline for 2 h after TBI. Rats treated with saline or D-arginine exhibited significant reductions in CBF that persisted throughout the monitoring period. Rats treated with L-arginine alone or in combination with SOD exhibited no decreases in CBF after TBI. CBF in the SOD-treated group decreased significantly within 15 min after TBI but returned to baseline levels by 45 min after TBI. These studies indicate that L-arginine but not D-arginine administered after TBI prevents posttraumatic hypoperfusion and that pretreatment with SOD will restore CBF after a brief period of hypoperfusion.

Animals↗

PubMed1997

Effects of nalmefene, CG3703, tirilazad, or dopamine on cerebral blood flow, oxygen delivery, and electroencephalographic activity after traumatic brain injury and hemorrhage.

Hemorrhage after traumatic brain injury (TBI) in cats produces significant decreases in cerebral oxygen delivery (DcereO2) and electroencephalographic (EEG) activity. To determine whether effective treatments for the separate insults of TBI and hemorrhagic shock would also prove effective after the clinically relevant combination of the two, we measured the effects of a kappa-opiate antagonist (nalmefene), an inhibitor of lipid peroxidation (tirilazad), a thyrotropin-releasing hormone analog (CG3703), a clinically useful pressor agent (dopamine) or a saline placebo on cerebral blood flow (CBF), and EEG activity after TBI and mild hemorrhagic hypotension. Cats (n = 40, 8 per group) were anesthetized with 1.6% isoflurane in N2O:O2 (70:30) and prepared for fluid-percussion TBI and microsphere measurements of CBF. Cats were randomized to receive nalmefene (1 mg/kg), tirilazad (5 mg/kg), CG3703 (2 mg/kg), dopamine (20 microg x kg(-1) x min[-1]) or a saline placebo (2 ml, 0.9% NaCl). Animals were injured (2.2 atm), hemorrhaged to 70% of preinjury blood volume, treated as just described and resuscitated with a volume of 10% hydroxyethyl starch equal to shed blood. CBF was determined and EEG activity recorded before injury, after hemorrhage, and 0, 60, and 120 min after resuscitation (R0, R60, and R120). CBF increased significantly after resuscitation (R0) in the nalmefene- and CG3703-treated groups. CBF did not differ significantly from baseline in any group at R60 or R120. DcereO2 was significantly less than baseline in the saline-, dopamine-, and tirilazad-treated groups at R60 and in the dopamine-, tirilazad-, and CG3703-treated groups at R120. EEG activity remained unchanged in the nalmefene-treated group but deteriorated significantly at R60 or R120 compared to baseline in the other groups. Nalmefene and CG3703 preserved the hyperemic response to hemodilution (otherwise antagonized by TBI), and nalmefene prevented the deterioration in DcereO2 and EEG activity that occurs after TBI and hemorrhage.

Animals↗

PubMed1997

Urinary continence following radical prostatectomy.

An examination was made of pre- and postoperative variables for predicting urinary continence following radical prostatectomy in 94 consecutive patients. Postoperative recovery of urinary continence continued for up to 18 months, when it plateaued. No pads were required in 73.0% of the patients at 18 months. The interval until recovery of urinary continence following surgery averaged 4.0 +/- 3.3 months. Clinical stage, pathologic stage, tumor grade, tumor volume, preservation of neurovascular bundles, methods of bladder neck reconstruction, internal urethrotomy for anastomotic stricture and postoperative adjuvant external beam radiation therapy provided no indication of postoperative urinary incontinence. Preoperative endocrine therapy, preoperative prostate-specific antigen level of > or = 10.0 ng/ml and age < 70 years at the time of surgery were all associated with a greater probability of urinary incontinence. Multiple factors are involved in the etiology of postprostatectomy urinary incontinence. In patients who had undergone surgery because of local progression following endocrine therapy associated with a high serum prostate-specific antigen level, a significantly inferior outcome was noted. Stricter criteria for indicating radical prostatectomy in patients with prostate cancer are needed. Surgical techniques should also be improved for better overall continence.

Adult↗

PubMed1997

Impact of life expectancy and tumor doubling time on the clinical significance of prostate cancer in Japan.

Theoretical projected prostate cancer volume at the time of expected death was determined based on patient age and index cancer volume at diagnosis, assumed cancer volume doubling time and life expectancy of the Japanese male population. Based on the data obtained, evaluation was made of the results for 104 consecutive radical prostatectomy cases with no prior treatment. Clinically insignificant cancer in 104 prostatectomy specimens was found to occur at 4.8, 10.6, 15.4 and 26.9% for tumor doubling times of 2, 3, 4 and 6 years, respectively. Assuming a 2-year doubling time with clinically insignificant cancer excluded, only 36.4% of significant cancers could be considered potentially curable and with a 3-year doubling time, 32.3%. For 4- and 6-year doubling times, only 30.7 and 25.0% of the clinically insignificant cancers were potentially curable, respectively. Approximately half of these insignificant cancers were clinically stage T1c disease. In all stage T1c cases, 8.8-47.1% was considered insignificant, depending on tumor doubling time. Patient life expectancy and tumor doubling time significantly determine the outcome of treatment for prostate cancer, especially in elderly males with higher risk of mortality. The outcome of radical prostatectomy is less satisfactory with these factors taken into consideration. Many patients with stage T1c disease may eventually prove to require no treatment.

Aged↗

PubMed1997

Sevoflurane or halothane anesthesia: can we tell the difference?

UNLABELLED: This study was performed to evaluate the ability of anesthesiologists to differentiate between sevoflurane, a newer, more expensive anesthetic, and halothane. A total of 113 assessments were made by 36 anesthesiologists on 58 children, aged 6 mo to 6 yr, scheduled for bilateral myringotomy and tube placement. All patients received midazolam (0.5 mg/kg per os) approximately 30 min before the induction of anesthesia. Sevoflurane or halothane was randomly selected for anesthetic induction and maintenance. The anesthesiologists, who were unaware of the anesthetic being used, were asked to identify the anesthetic based on clinical signs and to assess the quality of induction, speed of induction, and speed of emergence using a visual analog scale (VAS; minimum score = 0, maximum score = 100). The anesthesiologists correctly identified the anesthetic only 56.6% of the time. This was not significantly different from the 50% that would result from random guessing (P = 0.08). Further, there were no significant differences in VAS scores between the two groups. This study suggests that in premedicated pediatric patients undergoing brief surgical procedures, anesthesiologists cannot correctly differentiate between sevoflurane and halothane. The lack of significant differences in VAS scores suggests that the speed of induction, the speed of emergence, and the quality of induction are similar under these clinical conditions. Any purported benefits of sevoflurane seem to be of minor consequence under the circumstances studied. IMPLICATIONS: When the anesthetic halothane or sevoflurane is administered in a blind, randomized fashion, anesthesiologists could not reliably identify which drug was being used to anesthetize children for a brief surgical procedure. These results suggest that the differences between the two drugs in clinical practice are small and may not justify the additional cost of sevoflurane.

Anesthesia, Inhalation↗

PubMed1997

Elimination of adult T cell leukemia cells by ultrasound in the presence of porfimer sodium.

Sonodynamic effects using porfimer sodium (Photofrin; Pf) on leukemic and normal cells were evaluated. The purpose of this experiment was to compare cell survival among MT-2 cells, normal peripheral mononuclear cells (PMNCs) and adult T cell leukemia (ATL) patients' PMNCs after sonodynamic treatment. Cells were exposed to 450 kHz ultrasound at an intensity of 500 mW/cm2. The survival rate of MT-2 cells exposed to ultrasound alone for 80 s was 20.1 +/- 4.8%, whereas survival rates exposed to ultrasound in combination with 25, 50 and 100 microg/ml of Pf resulted in 11.5 +/- 2.9, 3.2 +/- 1.6 and 1.6 +/- 1.4%, respectively. There was a significant difference of cell survival between the group exposed to ultrasound alone and the Pf-combined groups (n = 6, p < 0.05). On the other hand, in the normal human PMNCs, no significant differences of cell survival rates were found between ultrasound-treated groups with and without Pf. We similarly examined the survival rate of PMNCs in the peripheral blood of five acute-type ATL patients (n = 5) after ultrasound (60 s, 300 mW/cm2) exposure with or without 100 microg/ml of Pf. Comparison of cell survival rate between ultrasound alone and ultrasound plus Pf showed significant differences (69.4 +/- 22.5 and 30.0 +/- 23.0%, respectively). There were no significant cytotoxicities in all Pf alone treated groups of the MT-2 cells, the normal PMNCs and the ATL patients' PMNCs (p < 0.05). It was suggested from this study that there was a specific selectivity of sonodynamic effects to MT-2 cell lines and ATL patients' PMNCs. It is anticipated that this new method of treatment, i.e. sonodynamic therapy, could be used for extracorporeal blood treatment of acute-type ATL patients.

Antineoplastic Agents↗

PubMed1997

Cerebral blood flow during experimental endotoxemia in volunteers.

OBJECTIVE: To measure cerebral blood flow, cerebral metabolic rate for oxygen, cerebral oxygen delivery, and cerebral vascular resistance during experimental endotoxemia in volunteers. DESIGN: Experimental, prospective study. SETTING: University general clinical research center. SUBJECTS: Healthy volunteers (six male, four female, 30.1 +/- 1.9 yrs of age). INTERVENTIONS: Volunteers had radial, pulmonary arterial, and jugular venous bulb catheters inserted. All volunteers received a bolus of Escherichia coli endotoxin (4 ng/kg). Cerebral blood flow was measured, using the Kety-Schmidt technique. MEASUREMENTS AND MAIN RESULTS: Cerebral and systemic hemodynamics and oxygenation variables were measured at baseline and hourly for 5 hrs after endotoxin administration. A systemic hyperdynamic response characterized by an increase in body temperature (97.9 +/- 0.02, 100.2 +/- 0.02, and 99.7 +/- 0.02 degrees F [36.6 +/- 0.01, 37.9 +/- 0.1, and 37.6 +/- 0.1 degrees C] at baseline, 3, and 5 hrs, respectively), cardiac index (3.7 +/- 0.2, 6.2 +/- 0.2, and 5.7 +/- 0.2 L/min/m2 at baseline, 3, and 5 hrs), and heart rate (70 +/- 2.6, 96 +/- 2.6, and 93 +/- 2.9 beats/min at baseline, 3, and 5 hrs), and a decrease in mean arterial pressure (99.3 +/- 2.2, 84.4 +/- 2.8, and 84 +/- 3.4 mm Hg at baseline, 3, and 5 hrs) and systemic vascular resistance (1498 +/- 53, 788 +/- 37, 849 +/- 36 dyne.sec/cm5.m2 at baseline, 3, and 5 hrs) followed the endotoxin bolus. Cerebral blood flow (65.4 +/- 4.3, 57.7 +/- 3.1, and 58.6 +/- 3.0 mL/100 g/min at baseline, 3, and 5 hrs), cerebral oxygen delivery (11.6 +/- 0.7, 9.8 +/- 0.6, and 9.5 +/- 0.6 mL/100 g/min at baseline, 3, and 5 hrs), cerebral metabolic rate for oxygen (3.8 +/- 0.4, 3.3 +/- 0.3, and 3.0 +/- 0.3 mL/100 g/min at baseline, 3, and 5 hrs), and cerebral vascular resistance (1.4 +/- 0.2, 1.4 +/- 0.2, and 1.3 +/- 0.2 mm Hg/mL/100 g/min at baseline, 3, and 5 hrs) were unchanged throughout the 5-hr study period. Signs of cerebral dysfunction were not apparent, although the volunteers appeared drowsy during the latter part of the study. CONCLUSION: A dose of endotoxin sufficient to induce systemic vasodilation in healthy subjects does not influence cerebral blood flow or the cerebral metabolic rate for oxygen.

Adult↗

PubMed1997

In situ expression of cell adhesion molecules in chronic gastritis with Helicobacter pylori infection.

Helicobacter pylori infection of the stomach results in acute inflammation followed by chronic inflammation, but the mechanism is unknown. Adhesion molecules such as ICAM-1, Mac-1, and LFA-1 may help regulate interactions of immune cells and inflammatory cells. We used immunohistochemistry to locate these molecules in the gastric mucosa of patients with chronic gastritis arising from H. pylori infection. Biopsy specimens were taken from five H. pylori-negative healthy volunteers and 20 H. pylori-positive patients with chronic gastritis for immunohistochemical studies of adhesion molecules. In the gastric mucosa of patients with H. pylori-associated chronic gastritis, ICAM-1 expression was prominent in most of the vessels and inflammatory cells, such as lymphocytes and granulocytes, in the lamina propria. However, no intraepithelial lymphocytes and surface epithelial cells expressed ICAM-1. Antigen-presenting cells (APCs), such as macrophages, expressed ICAM-1 as well as HLA-DR antigen. LFA-1 and Mac-1 were strongly expressed in these immune and inflammatory cells. The number of vascular endothelial cells positive for P-selectin was also greater in H. pylori-positive mucosa. The expression of these molecules decreased remarkably after successful eradication of H. pylori. In conclusion, ICAM-1 is the predominant form among the cell adhesion molecules that are expressed in response to chronic H. pylori infection. The increased expression of ICAM-1 is linked with massive infiltration of inflammatory cells that express LFA-1 and Mac-1, and also with APCs that express HLA-DR, suggesting that ICAM-1 exerts a key role in immuno-inflammatory responses in gastric mucosa of patients with H. pylori-associated gastritis.

Biopsy↗

PubMed1997

Mutations of the X region of hepatitis B virus and their clinical implications.

Nucleotide (nt) sequences of the X region of more than 130 hepatitis B virus (HBV) isolates were determined and derived from patients with a variety of clinical features. Correlation of nt substitutions with clinicopathological characteristics was attempted. The X region (465nt) is crucial for the replication and expression of HBV because the X protein transactivates the HBV genes and this region contains the core promoter, enhancer II, and two direct repeats. There are several mutational hotspots, some of which seem to relate to immunological epitopes of the X protein. Two kinds of mutations which have important clinical significances were found. One is an 8-nt deletion between nt 1770 and 1777, which truncates 20 amino acids from the carboxyl terminus of the X protein. This deletion leads to the suppression of replication and expression of HBV DNA, resulting in immunoserological marker (HBsAg) negativity. This silent HBV infection is responsible for the majority of non-A to non-E hepatitis. The other mutation substituting T for C (nt 1655), T for A (nt 1764) and A for G (nt 1766) seems to relate to fulminant hepatitis. Further sequencing studies and in vitro mutagenesis experiments will clarify the significance of other mutations of the X region.

Amino Acid Sequence↗

PubMed1997

Early detection of prune belly syndrome in utero by ultrasonography.

A report is presented of a male infant with prune belly syndrome (PBS) in whom bladder enlargement was detected by ultrasound (US) as early as 13 weeks of gestation. Subsequent fetal US identified progressive urinary tract dilatation, ascites and oligohydramnios. At 22 weeks, the fetal bladder was drained under US guidance. A gradual resolution of oligohydramnios was detected on US performed after 26 weeks of gestation. Delivery by cesarean section was performed at 34 weeks of gestation. The newborn had typical features of PBS with a vesico-cutaneous fistula but did not show respiratory distress. Imaging studies showed hypoplastic left kidney, slightly dysplastic but functioning right kidney, megaureter, megacystis, vesicoureteral reflux and dilated prostatic urethra. The early detection of genitourinary system abnormalities and serial US suggest that a distal urethral obstruction may be the underlying mechanism of PBS. Spontaneous (or therapeutic) intra-uterine decompression of the bladder might ameliorate obstructive nephropathy and oligohydramnios, allowing adequate lung development.

Adult↗

PubMed1997

Expression and self-assembly of empty virus-like particles of hepatitis E virus.

Hepatitis E virus (HEV) is a pathogenic agent that causes fecally-orally transmitted acute hepatitis. The genome, a single-stranded positive-sense RNA, encodes three forward open reading frames (ORFs), in which an approximately 2-kb structural protein is located in the 3' end. To produce HEV-like particles the structural protein, with its N terminus truncated (amino acid residues 112 to 660 of ORF2), was expressed in insect Tn5 cells by a recombinant baculovirus. In addition to the primary translation product with a molecular mass of 58 kDa, a large amount of a further-processed molecule with a molecular mass of 50 kDa was generated and efficiently released into the culture medium. Electron microscopic observation of the culture medium revealed that the 50-kDa protein self-assembled to form empty virus-like particles (VLPs). The buoyant density of the VLPs in CsCl was 1.285 g/cm3 and their diameter was 23.7 nm, a little smaller than the 27 nm of native HEV particles secreted into the bile or stools of experimentally infected monkeys. The yield of the VLPs was 1 mg per 10(7) cells as a purified form. The particles possess antigenicity similar to that of authentic HEV particles and, consequently, they appear to be a good antigen for the sensitive detection of HEV-specific immunoglobulin G (IgG) and IgM antibodies. Furthermore, the VLP may be the most promising candidate yet for an HEV vaccine, owing to its potent immunogenicity.

Animals↗

PubMed1997

Anisotropic repolarization in ventricular tissue.

Extracellular recording and stimulation techniques have been used to demonstrate that the effective refractory period of epicardial ventricular cells is significantly influenced by the sequence of activation. Whether myocardial fiber orientation is also important in determining the repolarization process is unclear. To determine the importance of fiber orientation on the repolarization process, we studied 12 blocks of pig right ventricular tissue in vitro. The size of each tissue block was 30 x 30 x 2 mm. Transmembrane action potentials were recorded, and effective refractory periods were measured from the preparation's epicardial surface, which showed nearly uniform fiber orientation. Tissues were paced at 500- and 1,000-ms cycle lengths. Sequential recordings were made at 1, 4, 7, 10, 13, and 16 mm from the stimulation site along and across the fibers. The results show that propagation of depolarization was much slower in the transverse direction than in the longitudinal direction. In the transverse direction, action potential duration was longest at the closest observation point, i.e., 1 mm from the stimulation, site (188 +/- 14 and 267 +/- 18 ms for 500- and 1,000-ms pacing cycle lengths, respectively). Action potential duration progressively shortened as the recording site was moved farther from the stimulation site (P < 0.001). The action potential duration 16 mm from the stimulation site was 165 +/- 11 and 247 +/- 12 ms for 500- and 1,000-ms pacing cycle lengths, respectively. In contrast, the action potential duration in the longitudinal direction did not change as the distance between the recording site and stimulation site increased. We conclude that, at physiological temperature and pacing cycle lengths, sequence of activation significantly influenced action potential duration when the propagation of activation was transverse to myocardial fiber orientation. When activation propagated parallel to fiber orientation, there was little or no change of action potential duration as distance increased.

Action Potentials↗