Cloning, characterization and genomic organization of LCC-1 (scya16), a novel human CC chemokine expressed in liver

By homology search of expressed sequence tags (EST) in GenBank a novel member of the CC chemokine family was identified. The full-length sequence of this liver-specific CC chemokine (LCC-1) predicted a mature protein of 97 amino acids with 31-48% identity to other CC chemokines. There was a characteristic amino acid C-term extension when aligned with other chemokines. Northern blot analysis from a panel of human tissues revealed that LCC-1 mRNA expression is restricted to adult and fetal liver. Different polyadenylation results in two mRNA species of 1.5 kb and 0.5 kb in size. LCC-1 is constitutively expressed in human HepG2 hepatoma cells and is induced by hypoxic exposure. The promoter region of the LCC-1 gene contains potential HIF-1 binding sites. The EST for LCC-1 has been previously mapped to the CC chemokine cluster on human chromosome 17q11.2. The organization of the LCC-1 gene (scya16) into three exons interrupted by two introns is identical to that found for other members of the CC chemokine family.

Forensic toxicological implication of acute fatal poisoning cases due to benfuracarb ingestion

We describe here three cases involving acute fatalities due to benfuracarb ingestion and the forensic toxicological implications. Benfuracarb, a carbamate insecticide and its main metabolite carbofuran, were detected using thin layer chromatography (TLC) and gas chromatography/mass spectrophotometry (GC/MS) after extraction with ethyl acetate and then quantified using gas chromatography (GC) equipped with NPD. The blood levels of benfuracarb and carbofuran were in the range of 0.30-2.32 microg/ml and 1.45-1.47 microg/ml, respectively. Benfuracarb was not detected in urine, but carbofuran was detected in the range of 0.53-2.66 microg/ml.

Studies on the sedative and hypnotic effects of oleamide in mice

The hypnotic and sedative effects of oleamide (CAS 301-02-0) were studied in mice. Intraperitoneal injection of oleamide showed a time-related inhibition of the locomotor activity with the maximum effect appearing 30 min after drug administration. Oleamide, at the dose range of 43.7-700 mg/kg, dose-dependently inhibited the locomotor activity in mice. Oleamide could promote the hypnotic action induced by sodium pentobarbital. The interaction studies showed that oleamide potentiated the inhibitory effect of diazepam (CAS 439-14-5) and antagonized the stimulatory effect of ethanol, methamphetamine, and caffeine, respectively. These results provide further evidence for the hypnotic and sedative effects of oleamide, suggesting a potential therapeutic usefulness of this fatty acid amide.

Criss-crossed interactions between the enhancer and the att sites of phage Mu during DNA transposition

A bipartite enhancer sequence (composed of the O1 and O2 operator sites) is essential for assembly of the functional tetramer of phage Mu transposase (MuA) on supercoiled DNA substrates. A three-site interaction (LER) between the left (L) and right (R) ends of Mu (att sites) and the enhancer (E) precedes tetramer assembly. We have dissected the role of the enhancer in tetramer assembly by using two transposase proteins that have a common att site specificity, but are distinct in their enhancer specificity. The activity of these proteins on substrates containing hybrid enhancers reveals a 'criss-crossed' pattern of interaction between att and enhancer sites. The left operator, O1, of the enhancer interacts specifically with the transposase subunit at the R1 site (within the right att sequence) that is responsible for cleaving the left end of Mu. The right operator, O2, shows a preferential interaction with the transposase subunit at the L1 site (within the left att sequence) that is responsible for cleaving the right end of Mu.

Change of plasma lipoproteins by heparin-released lipoprotein lipase

Lipoprotein lipase (LPL) is known to be attached to the luminal surface of vascular endothelial cells in a complex with membrane-bound heparan sulfate, and released into blood stream by heparin. LPL that catalyzes hydrolysis of triglyceride (TGL) on chylomicron and VLDL into two fatty acids and monoacylglycerol, is also implicated to participate in an enhancement of cholesterol uptake by arterial endothelial cells in vitro. But little is known about the LPL-mediated cholesterol uptake in physiological state. In this study, changes in blood lipid composition and levels of lipoproteins were determined after the injection of heparin in human. The level of LPL in plasma was increased from 0 to 11 mU/ml within 30-40 min post-heparin administration and decreased to the basal level within 2 h. The level of TGL in plasma decreased from 70 mg/dl to 20 mg/dl within 1 h and gradually increased to 80 mg/dl within 4 h. However the level of total cholesterol in plasma remained at 140 mg/dl during an experimental period of 4 h. Analysis of Lipoproteins in plasma by NaBr density gradient ultracentrifugation showed that the level of VLDL decreased from 50 mg/dl to 10 mg/dl within 1-2 h and returned to normal plasm level at 4 h. However there were no significant changes in the level of LDL and HDL. These results suggest that, at least, in normo-lipidemic subjects, increased free plasm LPL acts primarily on VLDL and failed to show any significant uptake of cholesterol-rich lipoproteins in human.

Long-term efficacy of plasma-derived hepatitis B vaccine: a 15-year follow-up study among Chinese children

To determine necessity and timing of booster of hepatitis B vaccine, we need to observe the duration of its protection. We report the results of a 15-year follow-up of a cohort of 649 children who participated a randomized, double blind, placebo-controlled trial on a plasma-derived hepatitis B vaccine in 1982. During the 15 years after vaccination, more vaccinated children had anti-HBs of 10 S/N ratios or over, compared with the controls, at all nine observations. At 15 years 50.0% (26/52) of the participants studied in the vaccinated group and 33.3% of the tested controls (18/54) retained anti-HBs levels of S/N ratios> or =10 (P < 0.09). However, since 5 years after vaccination, median S/N ratios of anti-HBs among the vaccinated children with detectable anti-HBs were lower than those of the controls except that detected at 15 years. 16.7% (9/54) of the tested children in the control group were HBsAg positive at 15 years after vaccination, in comparison with 1.9% (1/52) of the tested children in the vaccinated (P < 0.02). 28 chronic HBsAg carriers were identified in the control cohort over the 15 years, whereas only 1 case was noted in the vaccinated group (8.2% vs. 0.3%, P < 0.00001), corresponding to an efficacy of 96%.

Dynamics of nontypical apoptotic morphological changes visualized by green fluorescent protein in living cells with infectious pancreatic necrosis virus infection

Morphologically, apoptotic cells are characterized by highly condensed membrane blebbing and formation of apoptotic bodies. Recently, we reported that apoptosis precedes necrosis in a fish cell line infected with infectious pancreatic necrosis virus (IPNV). In the present study, we tested the possibility that nontypical apoptosis is a component of IPNV-induced fish cell death. A variant type of green fluorescent protein (EGFP) was expressed in a fish cell line such that EGFP served as a protein marker for visualizing dynamic apoptotic cell morphological changes and for tracing membrane integrity changes during IPNV infection. Direct morphological changes were visualized by fluorescence microscopy by EGFP in living cells infected with IPNV. The nontypical apoptotic morphological change stage occurred during the pre-late stage (6 to 7 h postinfection). Nontypical apoptotic features, including highly condensed membrane blebbing, occurred during the middle apoptotic stage. At the pre-late apoptotic stage, membrane vesicles quickly formed, blebbed, and were finally pinched off from the cell membrane. At the same time, at this pre-late apoptotic stage, apoptotic cells formed unique small holes in their membranes that ranged from 0.39 to 0.78 micrometer according to examination by scanning electron microscopy and immunoelectron microscopy. Quantitation of the intra- and extracellular release of EGFP by CHSE-214-EGFP cells after IPNV infection was done by Western blotting and fluorometry. Membrane integrity was quickly lost during the late apoptotic stage (after 8 h postinfection), and morphological change and membrane integrity loss could be prevented and blocked by treatment with apoptosis inhibitors such as cycloheximide, genistein, and EDTA before IPNV infection. Together, these findings show the apoptotic features at the onset of pathology in host cells (early and middle apoptotic stages), followed secondarily by nontypical apoptosis (pre-late apoptotic stage) and then by postapoptotic necrosis (late apoptotic stage), of a fish cell line. Our results demonstrate that nontypical apoptosis is a component of IPNV-induced fish cell death.

Levels of paraquat in fatal intoxications

We describe here fatal levels of paraquat in plasma of victims due to the ingestion of the herbicide, paraquat, and the relationship between those levels and survival times after ingestion. We determined paraquat levels in plasma of 106 paraquat poisoning cases in Korea between June 1992 and December 1996 using a visible spectrophotometric method based on the alkali-dithionite reaction. Among 55 cases with known survival times, plasma paraquat levels of victims who died within one day of ingestion ranged from 2.3 to 636.6 microg/ml (average 127.6 microg/ml) while those of the victims who died between 1 approximately 4 days ranged from 0.9 to 25.1 microg/ml (average 7.0 microg/ml). Since preparations containing 24.5% paraquat dichloride are still used in Korea, our data for Korean victims who died within one day were 8.5 times higher than those in Baselt and Cravey's report for the same survival times. Our data also suggest that victims in whom a plasma paraquat concentration of more than 30 microg/ml was detected are likely to have died within 24 h after ingestion.

Assessment of myocardial viability using 123I-labeled iodophenylpentadecanoic acid at sustained low flow or after acute infarction and reperfusion

123I-labeled iodophenylpentadecanoic acid (IPPA) is a synthetic fatty acid that may be useful for determination of myocardial viability. We investigated the uptake and clearance kinetics of this tracer in canine models of ischemia and infarction.

METHODS

In protocol 1, 185 MBq (5 mCi) 123I-IPPA were injected intravenously in 19 dogs with 50% left anterior descending artery (LAD) flow reduction. In 9 dogs, 201TI was coinjected. In protocol 2, 5 dogs underwent LAD occlusion for 3 h, and 123I-IPPA was injected 60 min after reperfusion. All dogs had flow measured by microspheres, regional systolic thickening by ultrasonic crystals and measurements of postmortem risk area and infarct size. Tracer activities were quantified by gamma well counting and by serial imaging.

RESULTS

In protocol 1 dogs with sustained low flow (50% +/- 4%) and absence of systolic thickening (-3.2% +/- 1%), 123I-IPPA defect magnitude (LAD/left circumflex artery [LCX] count ratios) decreased from 0.65 +/- 0.02 to 0.74 +/- 0.02 at 30 min and to 0.84 +/- 0.03 at 2 h (P < 0.01), indicative of rest redistribution. Final transmural 123I-IPPA LAD/LCX activity ratio (0.99 +/- 0.05) was significantly greater than the flow ratio (0.53 +/- 0.04) at injection, confirming complete rest redistribution. The final 123I-IPPA activity ratio was significantly greater than the 201TI ratio over the 2-h period (P < 0.01). In protocol 2 dogs that underwent 3 h of total LAD occlusion and reflow (infarct size = 51% +/- 13% of risk area), viability was overestimated with 123I-IPPA, because uptake averaged 64% of normal in the central necrotic region, where flow averaged < 10% of normal.

CONCLUSION

These findings suggest that serial 123I-IPPA imaging may be useful for assessing myocardial viability under conditions of sustained low flow and myocardial asynergy, such as appears to exist in patients with chronic coronary artery disease and depressed left ventricular function. In contrast, 123I-IPPA given early after reperfusion following prolonged coronary occlusion overestimates the degree of viability and therefore may not provide useful information pertaining to the degree of myocardial salvage after reflow in the setting of acute myocardial infarction.

Symptomatic tracheal stenosis in burns

Tracheal stenosis in burns is rare and usually results from prolonged intubation or tracheostomy. Inhalation injury itself has the potential risk of tracheal stenosis. We reviewed the records of 1878 burn patients during 1987 to 1995 and found seven with tracheal stenosis (0.37%) after an average of 4.4 years follow up. There were 4 males and 3 females with an average age of 27.3 years. The tracheal stenosis developed 1-22 months after burn (average 7 months). Five patients had their inhalation injury confirmed by bronchoscopic examination. The incidence of tracheal stenosis among inhalation injury patients was 5.49% (5/92). Six patients needed intubation in the initial stage either for respiratory distress or prophylaxis, with an average duration of 195.2 h. In addition to prolonged intubation, the presence of inhalation injury, repeated intubations and severe neck scar contractures are also contributors to tracheal stenosis in burns. We favor T-tube insertion as the first treatment choice; permanent tracheostomy was unsatisfactory in our study.

Heterozygous defect in HIV-1 coreceptor CCR5 and chemokine production

CC chemokine receptor 5 (CCR5) is a cell entry cofactor for macrophage-tropic isolates of human immunodeficiency virus 1 (HIV-1). An inactive CCR5 allele with a 32-nucleotide deletion (CCR5Delta32) has been described that confers resistance to HIV-1 infection in homozygotes and slows the rate of progression to AIDS in heterozygotes. We found the allele CCR5Delta32 to be not rare in 399 Swiss blood donors with a frequency of 0.080. To assess the influence of defective CCR5 on production of its ligands we determined the capacity to produce the chemokines macrophage inflammatory protein (MIP)-1alpha, MIP-1beta and RANTES in comparison with the production of the CXC chemokine IL-8 which does not bind to CCR5. Production of chemokines was determined during endotoxin stimulation of whole-blood samples ex vivo. Both, basal and LPS-induced chemokine production in 32 blood donors heterozygous for CCR5Delta32 were not significantly different when compared with 55 blood donors who were homozygous for the wild type CCR5 allele.

Pilot in vitro toxicity study of 5-ALA and Photofrin in microvascular endothelial cell cultures

Complicated hemangiomas are unique problems in which intervention with the proper laser can be an ideal solution. In this study we evaluated the toxicity of 5-Aminolevulinic acid (5-ALA) and Photofrin using in vitro models. The in vitro toxicity of 5-ALA and Photofrin was examined in a microvascular endothelial cell (MEC) culture system. The measurement of the percentage of MEC killed by various drug concentration using fluorescence viability assay. MEC incubated with 5-ALA at various concentrations for evaluation of dark toxicity showed less than a 50% cell kill. A comparison of different intervals of subcultured MEC showed that the early subculture (3 days after primary culture) is more vulnerable than later subculture (7 days after). Cells treated with Photofrin at various concentrations exhibited less than 50% cell kill (dark toxicity). The comparison of different intervals of subculture (3 days and 7 days after primary culture) showed a result similar to that of 5-ALA. All controls showed 0% cell kill. In conclusion, both 5-ALA and Photofrin are capable of destroying human microvascular endothelial cells in vitro. Drug concentrations and the power density for photodynamic therapy should be considered and will be included in our subsequent studies.

Effect of antioxidant in endothelial cells exposed to oxidized low-density lipoproteins

Antioxidants such as probucol and alpha-tocopherol have been shown to attenuate the oxidation of low-density lipoproteins (LDL) and atherosclerotic lesions in animal models of atherosclerosis. The purpose of this study is to determine the protection effect of antioxidants on endothelial cells when exposed to oxidized and native LDL. In a cell-free system, we found that probucol, alpha-tocopherol, and ascorbic acid inhibited copper-induced LDL oxidation by a dose-dependent fashion (from 1 microM to 10 mM). In porcine aortic endothelial cells, antioxidants alone did not change basal endothelin-1 (ET-1) secretion. When porcine aortic endothelial cells were exposed to LDL and oxidized-LDL, both of them stimulated ET-1 secretion dose-dependently, whereas oxidized-LDL elicited higher ET-1 secretion. However, probucol, alpha-tocopherol, and ascorbic acid did not prevent LDL or oxidized-LDL induced ET-1 secretion. Furthermore, nimodipine inhibited both of native and oxidized LDL induced ET-1 secretion. Since Ca2+ channel blocker reduced the elevation of induced ET-1 secretion, the [Ca2+]i is possibly involved for the regulation of ET-1 secretion. Our results suggest that antioxidants can only prevent the oxidation of LDL rather than oxidized and native LDL-induced ET-1 secretion in vascular endothelial cells. The increase in the [Ca2+]i of endothelial cells through the opening of voltage-dependent Ca2+ channels may be involved in the LDL-induced ET-1 release.

Clinical experience of postage stamp autograft with porcine skin onlay dressing in extensive burns

Fifteen patients with extensive burns (deep second-degree burn > 50%, or third-degree burn > 30% of total body surface area) were treated with postage stamp autograft and meshed porcine skin onlay dressing from 1992 to 1996. All patients received the procedure within 10 days of sustaining the burn, with an average of 6.3 days. The areas chosen for postage stamp autograft were the anterior chest, abdomen, back, buttocks and the proximal part of the extremities. The scalp was the donor site of choice when available. The harvested skin was cut into 0.5-1.0 cm postage-stamp-like squares and applied to the recipient sites separated by a distance of 0.5-2.0 cm. The expansion ratio was from 1:4 to 1:9. Meshed porcine skin was then used for onlay dressing. The average graft area was 26% of the total body surface area. The success rate of the skin grafts was nearly 100% in 14 patients. One patient had a 40% loss due to contamination from adjacent wounds. In conclusion, the postage stamp autograft with porcine skin overlay is an effective way to treat extensive burn wounds in the early stages.

The interaction of glomerular mesangial cells and epithelial cells

The interaction of cells within the glomerulus plays an important role in the development and progression of glomerular disease. To investigate the interaction of glomerular mesangial cells (GMC) and epithelial cells (GEC), and mediator(s) of this interaction, we investigated the effect of Adriamycin (doxorubicin hydrochloride)-induced (ADR) rat GMC-conditioned medium (GMC-CM) on the incorporation of 35S, 3H-leucine, and 3H-thymidine in normal rat GEC, as well as 3H-thymidine uptake by normal rat GMC in response to ADR-rat GEC-CM. In addition, changes in the responsiveness to interleukin-6 (IL-6) and the products of IL-6 were assessed in ADR-rat GMC. The results showed that: (1) GMC-CM of ADR-rat with heavy proteinuria stimulated GEC proliferation and the synthesis of sulfated compounds and protein, while the GEC-CM of ADR-rat from the same nephrotic period increased GMC proliferation; (2) the ADR-rat GMC had altered responsiveness to IL-6 and its products. The stimulation index results demonstrated the interaction of GMC and GEC in the ADR-induced rat model, and that this interaction related closely to the degree of proteinuria and was mediated by soluble products of the damaged glomerular cell.

Use of the scalp as a donor site for large burn wound coverage: review of 150 patients

The characteristics of rapid wound healing and multiple harvest capacity make the scalp an important donor site when dealing with large and deep burn wounds. This paper reports the results of a retrospective analysis of 150 patients treated for large burn wounds. The findings indicated that bleeding during graft skin harvest could be limited to 50 ml by intradermal injection of epinephrine (1:2,000,000), high-concentration epinephrine-soaked gauze compression (1:20,000), and temporary porcine skin coverage. Use of a scalp graft also carried a low risk of complications, with only four (2.7%) major complications including three cases (2.0%) of visible alopecia and one case (0.7%) of hair transplantation. There were no hypertrophic scars, even in the patient who had the largest number (11) of repeat harvests.

Mutational analysis of domain II beta of bacteriophage Mu transposase: domains II alpha and II beta belong to different catalytic complementation groups

This study examines the contribution of domain II beta of bacteriophage Mu transposase (A protein), a subdomain of the central catalytic domain II, to the transposition reaction. The properties of several point mutations implicate a role for this domain in facilitating metal-assisted assembly of the synaptic complex, as well as in intramolecular DNA strand transfer. Point mutations as well as deletions in domain II beta can be complemented by those in domain II alpha but not those in domain III alpha. Thus, residues within subdomains II alpha and II beta belong to different catalytic complementation groups.

Surveillance of anti-hantavirus antibodies among certain high-risk groups in Taiwan

Hemorrhagic fever with renal syndrome is a serious health concern in neighboring countries of Taiwan, such as mainland China and Korea. In Taiwan, only two suspected cases were recorded before 1994. The first confirmed case was reported in 1995, but this proved to be imported. To study hantavirus infection in Taiwan, we tested blood collected from garbage collectors, animal handlers, patients with febrile illness of unknown origin, and field rats, the host of hantavirus, for the presence of antibody against hantavirus using an indirect immunofluorescent antibody technique. The positive rates were 1.55% (3/193), 3.45% (1/29), 1.42% (3/211), and 5.56% (9/162), respectively. The subtypes of hantavirus involved were either Hantaan-like or Seoul-like. These results showed that hantavirus may have already invaded Taiwan without our knowledge and physicians should be aware of this.

A randomized, double-blind clinical trial comparing cefepime plus metronidazole with imipenem-cilastatin in the treatment of complicated intra-abdominal infections. Cefepime Intra-abdominal Infection Study Group

OBJECTIVE

To evaluate the safety and efficacy of cefepime hydrochloride plus metronidazole vs the combination of imipenem and cilastatin sodium in the treatment of complicated intra-abdominal infections in adult patients.

DESIGN

Prospective, randomized, double-blind multicenter study.

SETTING

University-affiliated hospitals in the United States and Canada.

PATIENTS

Three hundred twenty-three patients with complicated intra-abdominal infections in whom an operative procedure or percutaneous drainage was required for diagnosis and management.

INTERVENTION

Cefepime, 2 g, was administered intravenously every 12 hours (n= 164) in addition to metronidazole, 500 mg (or 7.5 mg/kg) intravenously every 6 hours. Imipenen-cilastatin sodium, 500 mg, was administered intravenously every 6 hours (n= 159). Surgical infection management was determined by the patients' surgeons. MAIN OUTCOME ASSESSMENTS: Clinical cure, defined as elimination of all signs and symptoms relevant to the original infection; and treatment failure, defined as persistence, increase or worsening of signs and symptoms resulting in an antibiotic change, requirement of an additional surgical procedure to cure the infection, or a wound infection with fever.

RESULTS

Of the initial isolates, 84% were susceptible to cefepime and 92% were susceptible to imipenem-cilastatin. Among the 217 protocol-valid patients, those treated with cefepime+metronidizole were deemed clinical cures (88%) more frequently than were imipenem-cilastatin-treated patients (76%) (P=.02). Using multivariate analysis to adjust for identified clinical risk factors for an adverse outcome (severity of presenting illness, isolation of enterococcus, type of infection, and duration of prestudy hospitalization), there was a trend (P=.06) toward a higher cure rate favoring cefepime+metronidazole. Pathogens were eradicated in significantly (P=.01) more patients treated with combined cefepime and metronidazole (89%) than with imipenem-cilastatin (76%).

CONCLUSION

The combination of cefepime plus metronidazole is safe and effective therapy for patients with severe intra-abdominal infections.

Antioxidants for prevention of methionine oxidation in recombinant monoclonal antibody HER2

Recombinant humanized monoclonal antibody HER2, rhuMAb HER2, in liquid formulations undergoes oxidation when exposed to intense light and elevated temperatures (30 & 40 degrees C). Met-255 in the heavy chain of the Fc region of the antibody is the primary site of oxidation. Met-431 of the Fc fragment can also be oxidized under extreme conditions. The amount of oxidation was determined by cleaving the Fab and Fc fragments by papain digestion, and the oxidized Fc fragment was detected by hydrophobic interaction chromatography. Oxidation of rhuMAb HER2 was also formulation dependent. The presence of NaCl in the rhuMAb HER2 formulation caused an increase in oxidation at higher temperatures after contact with stainless steel containers or stainless steel components in the filling process. The corrosion of stainless steel by chloride ions at the low pH of the formulation buffer generated iron ions that catalyzed methionine oxidation in rhuMAb HER2. Temperature-induced oxidation of rhuMAb HER2 occurred by the formation of free radicals, and light-induced oxidation of rhuMAb HER2 occurred via single oxygen pathway. Antioxidants, such as methionine, sodium thiosulfate, catalase, or platinum, prevented Met oxidation in rhuMAb HER2, presumably as free radicals or oxygen scavengers. The minimum effective levels (molar ratios of protein to antioxidant) required to inhibit temperature-induced oxidation were 1:5 and 1:25 for methionine and thiosulfate, respectively. A thiosulfate adduct of rhuMAb HER2 was observed by cation-exchange chromatography. These studies demonstrate that stoichiometric amounts of methionine and thiosulfate are sufficient to eliminate temperature-induced oxidation of rhuMAb HER2 caused by free radicals that were generated by the presence of metal ion and peroxide impurities in the formulation.

Myocardial 99mTc-tetrofosmin uptake during adenosine-induced vasodilatation with either a critical or mild coronary stenosis: comparison with 201Tl and regional myocardial blood flow

BACKGROUND

Clinical studies have shown a comparable coronary stenosis detection rate between 99mTc-tetrofosmin and 201Tl but with smaller defect magnitudes for 99mTc-tetrofosmin. The goals of this study were to measure the first-pass extraction fraction (EF) of 99mTc-tetrofosmin in canine myocardium and to compare 99mTc-tetrofosmin with 201Tl uptake during adenosine-induced vasodilatation in dogs with various degrees of coronary stenosis.

METHODS AND RESULTS

EF was calculated in 4 anesthetized, open-chest dogs after intracoronary administration of 125I-labeled albumin and 99mTc-tetrofosmin. In another 16 dogs with either critical (n=6) or mild (n= 10) left anterior descending coronary artery (LAD) stenoses, 201Tl and 99mTc-tetrofosmin were administered during adenosine infusion (250 microg x kg(-1) x min(-1)). Dogs were killed 5 minutes later, and tracer activities were determined by ex vivo imaging of heart slices and by well counting. Mean 99mTc-tetrofosmin EF was 54.0+/-3.7%. In the 6 critical-stenosis dogs, the LAD-to-left circumflex artery (LCx) microsphere flow ratio was 0.22+/-0.02 with adenosine. The LAD-to-LCx activity ratios were 0.37+/-0.04 for 201Tl and 0.67+/-0.05 for 99mTc-tetrofosmin (P<.01). For the 10 mild-stenosis dogs, the LAD-to-LCx flow ratio was 0.44+/-0.05. The 201Tl activity ratio was 0.58+/-0.04, compared with 0.81+/-0.04 for 99mTc-tetrofosmin (P<.01). Thus, in both groups, 99mTc-tetrofosmin uptake underestimated the flow disparity more than 201Tl. Similarly, magnitudes of ex vivo image defects were significantly greater for 201Tl than for 99mTc-tetrofosmin in both groups.

CONCLUSIONS

In this canine model, relative underperfusion with adenosine stress is better resolved with 201Tl than with 99mTc-tetrofosmin and may be explained by the lower EF for 99mTc tetrofosmin. With clinical imaging, greater 201Tl attenuation and redistribution may lessen this advantage.

Alport syndrome with neurofibromatosis type-I: a case report

We report a 9-year-old boy with repeated fractures of the tibia from age 6 months and microscopic hematuria from age 2 years. His maternal family has a history of nephritis and his paternal family has neurofibromatosis type-I (NF-I). The boy's renal biopsy revealed an irregular attenuation and splitting of the glomerular basement membrane. The skin biopsy was stained with monoclonal antibody against the alpha 5 chain of type IV collagen; the epidermal basement membrane was negative in the boy and segmentally positive in the boy's mother. We conclude that the patient inherited Alport syndrome from his mother and NF-I from his father. We postulate this was a chance association and that this case does not suggest any relationship between the two diseases.

99Tcm-MDP scintigraphy in high-voltage electrical burn patients

In high-voltage electrical burn injuries (> 1000 V), it is difficult to identify the site and extent of non-viable deep tissue damage for debridement to avoid further tissue injury from wound infection and the risk of sepsis. This prospective study was designed to evaluate the usefulness of 99Tcm-methylene di-phosphonate (99Tcm-MDP) scintigraphy in detecting the extent of tissue injury and determining the level of amputation required for electrical burn patients. Over a 5 year period, 33 high-voltage electrical burn patients were studied. Blood flow and blood pool studies revealed absent perfusion in 37 limbs, all of which eventually were amputated. In addition to a routine three-phase bone scan, images were obtained at 30-60 min (early images) to evaluate whether soft tissue injury could be detected better at that time. For comparison of the detection rate from the early images and bone (delayed) images, 164 corresponding spot views of both images were reviewed. Eighty-three and 125 tissue necrotic lesions were demonstrated by the early images and bone images respectively. All of the 83 lesions found by the early images were more clearly identified by the bone images. All but one of the 125 lesions underwent surgical debridement or amputation. We concluded that the blood flow and blood pool images correlated well with the level of amputation required. The site and extent of tissue necrotic lesions can be clearly identified on 99Tcm-MDP bone scans. Because the early images were less sensitive in detecting tissue necrosis, we suggest that early imaging is not necessary.

Structure and origin of HIV type 1 DNA in persistently infected B lymphoblastoid cell lines

The Epstein-Barr virus (EBV) and human immunodeficiency virus type 1 (HIV-1) can coinfect resting B cells, leading to EBV-carrying lymphoblastoid cell lines (LCLs) persistently infected with HIV-1. LCLs established from coinfected peripheral blood lymphocytes (PBLs) differed from LCLs derived from HIV-1-infected cell lines, in that the majority if not all of the cells expressed gp120 and a high percentage produced infectious HIV-1 after continuous passage for 6-9 months. Restriction analysis of the putative HIV-1 provirus revealed that persistently infected LCLs carried variable copies of primarily unintegrated circular and/or linear forms of HIV-1 DNA. This extrachromosomal location is strikingly different from that of the one to three copies of integrated proviral DNA deleted in persistently infected T cell and monocytic cell lines. Anti-gp120 monoclonal antibody and 3'-azido-3'-deoxythymidine (AZT) inhibited HIV-1 expression and reduced HIV-1 DNA copy number in persistently infected LCLs, supporting the hypothesis that unintegrated HIV-1 DNA accumulates primarily as a result of superinfection. We propose that the extrachromosomal location of the HIV-1 DNA contributes to the semipermissive nature of B cell infection by HIV-1.