Liposomes-coated hydroxyapatite and tricalcium phosphate implanted in the mandibular bony defect of miniature swine

Hydroxyapatite and tricalcium phosphate have been used as bone implants for some period of time. Now unfortunately, these materials have failed to become the nucleation sites for bone regeneration. We hypothesized that coating hydroxyapatite and tricalcium phosphate with negatively charged liposomes may improve the nucleation process for new bone formation. The present study was designed to test this hypothesis. Experiments were carried out in 15 miniature swines' mandibular angle with artificial bony defects. In each of the swine, the bony defects on one side were implanted with either liposomes coated with hydroxyapatite or liposomes coated with tricalcium phosphate, while the other side served as control. At the end of the third and sixth weeks following the operation, we observed result, took histology and radiographs of the operated area. The results showed that liposomes-coated materials were biocompatible and their clinical endpoint was enhanced. At the end of the third week, the implant material was surrounded by dense connective tissues. At the end of the sixth week, there were new bone formations near the implanted material. In addition, liposomes which were immobilized in agarose gel and implanted in the defects showed new bony bridge formation. These observations suggest that liposomes have the ability in promoting repair of osseous deficiencies.

Detection of in vivo P-glycoprotein inhibition by PSC 833 using Tc-99m sestamibi

Tc-99m sestamibi is a substrate of P-glycoprotein (Pgp) that has been proposed for use as a functional imaging agent for the multidrug resistance-1 phenotype. In vitro, retention of sestamibi by cells that overexpress Pgp can be modified by the presence of Pgp antagonists. In a Phase I trial of the Pgp reversal agent PSC 833, we show that the effects of this reversal agent can also be demonstrated in patients. Nine patients with metastatic renal carcinoma were studied three times: at baseline, approximately 1 day after vinblastine infusion, and while on PSC 833. One patient with metastatic adrenocortical cancer was also studied. Time activity curves and areas under the curve (AUCs) were obtained for tumor, liver, lung, and myocardium, and organ:heart AUC ratios were generated. With PSC 833, tumor visualization was enhanced, and statistically significant increases were found in AUC ratios for tumor and liver compared to baseline. For the liver, significant differences were also found between the vinblastine versus PSC 833 scans but not between the baseline versus vinblastine scans. This study demonstrates that sestamibi retention by tumor and liver is altered in the presence of the reversal agent PSC 833, presumably reflecting inhibition of Pgp. Thus, sestamibi may be useful in vivo as a means of monitoring the effects of this and other reversal agents on various tumors and normal tissues that express Pgp.

Morphine augmentation increases gallbladder visualization in patients pretreated with cholecystokinin

The purpose of this study was to determine if a combination of cholecystokinin (CCK) pretreatment followed by morphine augmentation improved the detection of cystic duct patency compared with CCK pretreatment only.

METHODS

One hundred fifty-five patients with suspected acute cholecystitis had scintigraphy performed with 185-481 MBq (5-13 mCi) 99mTc-mebrofenin adjusted to the patients' total bilirubin levels. All patients were pretreated with 0.02 microgram/kg sincalide injected intravenously over 3-5 min. Sequential imaging was performed until gallbladder activity was identified or up to 90 min postinjection of mebrofenin. If no gallbladder was identified, a second dose of mebrofenin was given as necessary to have tracer in the biliary system. Then, 0.04 mg/kg intravenous morphine sulfate was administered, followed by imaging for up to 30 min or until gallbladder visualization.

RESULTS

Twenty-eight percent (43/155) of the patients pretreated with CCK had nonvisualization of the gallbladder at 90 min postinjection of radiotracer. After intravenous morphine, the gallbladder was identified in 42% (18/43) of these patients (p = 0.0001).

CONCLUSION

Hepatobiliary imaging with CCK pretreatment and imaging for 90 min was insufficient to identify all patent cystic ducts. Morphine augmentation significantly increased the frequency of gallbladder visualization in patients pretreated with CCK.

The psychiatric manifestation of Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is considered to be very rare in the population, and the psychiatric manifestation of the disease even rarer with only one report in the past few years in Taiwan. To clarify whether the psychiatric manifestation of CJD is really rare or whether it is neglected in Taiwan, the authors reviewed the discharge notes of patients who had been admitted to a neurological unit in the past 15 years and conducted a chart review of the patients of CJD supported by the clinical courses, EEG finding and brain biopsies. An inquiry was made by telephoning their families to follow up their condition after discharge. Five of the 8 cases with CJD had psychiatric symptoms including changes of mood, thought, behavior and perception during their course of illness. Four cases had been sent to the psychiatric unit and received treatment under several kinds of psychiatric diagnoses. Two patients had been admitted to the psychiatric unit and one had received electroconvulsive treatment. Two of the patients had been suspected to be the victims of neuroleptic malignant syndrome. It is likely that it is psychiatrists who will meet CJD patients first in the early stages of disease. CJD should be kept in mind and EEGs with detailed neurological checkups should be completed, if the cognitive functions of the patients with unusual neurological symptoms deteriorate quickly and their psychiatric symptoms fail to respond to any treatment.

A role for calcineurin in the desensitization of the P2X3 receptor

The sensory neurone-specific ATP-gated cation channel P2X3, when expressed in Xenopus oocytes, desensitizes rapidly. Complete removal of extracellular calcium abolishes desensitization. Pretreatment of oocytes with cyclosporin also abolishes P2X3 desensitization. When the calcineurin auto-inhibitory peptide (CaN A457-481) was injected into oocytes, the rate of desensitization of P2X3 decreased on consecutive applications of ATP, suggesting a role for calcineurin in the regulation of desensitization. Truncated P2X3 clones initiating at Met-75 lack the N-terminal intracellular region, but express functional channels in oocytes that do not desensitize. Taken together, these data suggest that P2X3 desensitizes through a calcium-dependent calcineurin-mediated dephosphorylation involving N-terminal residues that are phosphorylated in functional channels.

Right-sided cardiac tumors detected by transesophageal echocardiography and its usefulness in differentiating the benign from the malignant ones

Eighteen patients (3 men and 15 women; mean age 63 years) with right-sided tumors were evaluated by both transthoracic and transesophageal echocardiography from 1989 to 1996. The indications for echocardiographic studies included evaluation for a presumed mass and further evaluation of ventricular function and valvular function. Fifteen patients had right atrial tumors. These included 5 hypernephromas, 4 myxomas, 2 angiosarcomas, 1 lipoma, 1 cavernous hemangioma, 1 hepatoma, and 1 chondrosarcoma. Three patients had right ventricular (RV) tumors: 1 metastatic olfactory neuroblastoma, a leiomyosarcoma, a chondrosarcoma, and a fourth patient had infiltration of the RV free wall of unknown etiology. Biopsy of either right atrial or RV masses was performed with transesophageal echocardiographic guidance in 2 patients, and allowed histologic diagnosis before surgical resection. These findings indicate that tumors are more often found in the right atrium than in the right ventricle, and females predominate. Most tumors arising within the right atrium are benign, whereas those extending into the right atrium from outside are malignant. RV tumors are rarely encountered; when present, they are likely to be malignant.

Postoperative MRI of anorectal malformation

Twenty-five patients who had pull-through rectum (PTR) surgery, some of whom suffered from fecal incontinence, soiling or constipation were studied by magnetic resonance imaging (MRI) postoperatively. MRI demonstrated 14 patients with proper placement of the PTR between the puborectal muscle and external sphincter muscle; four patients with improper placement of the PTR outside the puborectal muscle and external sphincter muscle (one with excess perirectal fat); one patient with disruption of the puborectal muscle and external sphincter muscle; three with hypoplasia of the puborectal muscle and external sphincter muscle; three with asymmetric placement of PTR in the levator ani (one with excess perirectal fat). MRI also depicted seven patients with spine anomalies; five with tethered cord; and 10 with genitourinary tract anomalies. The patients with correct location of PTR all had good fecal continence except three patients (two with soiling and one with constipation) who had tethered cord and ganglion cell dysfunction at the PTR. The patients with improper placement of PTR or poorly developed pelvic muscles all had fecal incontinence. Our study emphasizes that MRI can depict the causes of postoperative incontinence, detect anomalies and help to plan further surgery.

Collagen synthesis in idiopathic and dilantin-induced gingival fibromatosis

Gingival fibromatosis is an uncommon but benign oral disease which causes progressive and non-hemorrhagic enlargement of the gingiva. There are two types of gingival fibromatosis: idiopathic gingival fibromatosis (GF), which is of unknown cause and may be associated with hereditary factors, and drug-induced gingival fibromatosis which is caused primarily by phenytoin intake. In cases of gingival fibromatosis, either the teeth are delayed in emergence or most of the crowns are embedded in the soft tissue even after full eruption. The objective of this study was to examine the basis of excess collagen formation in the two types of gingival fibromatosis in four patients admitted to the dental clinic at Kaohsiung Medical College Hospital, Kaohsiung, Taiwan. There were two male patients, aged ten (Case 1) and sixteen (Case 2), with idiopathic gingival fibromatosis and hypertrichosis, and two female patients, aged sixteen (Case 3) and eleven (Case 4), with Dilantin-induced gingival hyperplasia (DGH). Cultures of gingival fibroblast were established either from clinically excised hyperplastic tissues or from pre-orthodontic surgical normal gingiva. The synthesis of collagen and levels of prolyl hydroxylase, a key enzyme in collagen synthesis, were examined in the healthy and affected fibroblasts. Our studies showed that after two days in culture, fibroblasts from all four patients multiplied faster than healthy gingival fibroblasts, though the amount of DNA and protein per cell remained unchanged. In addition, all cultures (except Case 1) had a 2- to 3- fold increase of prolyl hydroxylase activity over that of the controls. As in the cases of prolyl hydroxylase activity, Case 1 did not show any change in collagen synthesis when compared to the control. However, Cases 2, 3, and 4 showed appreciable collagen increases in the cell and medium: 61% and 60% for Case 2; 16% and 36% for Case 3; and 21% and 80.7% for Case 4 respectively.

Periodontal manifestations and treatment of Sturge-Weber syndrome--report of two cases

Encephalotrigeminal angiomatosis (Sturge-Weber syndrome) is a rather uncommon congenital condition characterized by the combination of venous angioma of the leptomeninges over the cerebral cortex with ipsilateral angiomatous lesions of the face and sometimes, the skull, jaws and oral soft tissues. Two patients came to the Kaohsiung Medical College Hospital's dental clinic with complaints of localized gingival enlargement or tumor-like swelling. Based on the presence of facial nevus flammeus, examinations of angiography, radiological evidence of calcific densities, and ipsilaterally intraoral vascular hyperplasia in the lip, cheek and gingiva, encephalotrigeminal angiomatosis was diagnosed. Dental management included plaque control instructions, scaling, root planing and periodontal surgery. Recurrence of gingival enlargement in both cases was noted, so periodontal surgery was performed a second time. Close follow up and complete plaque control have kept the periodontal condition fairly well under control in these two cases. We introduce the oral manifestations and the experience of treatments in these two cases.

Blood levels of reduced haloperidol versus clinical efficacy and extrapyramidal side effects of haloperidol

1. The studies of relationships between blood levels of reduced haloperidol HL (RH) and clinical efficacy in haloperidol (HL)-treated patients have yielded variable results. On the other hand, the contribution of RH upon HL's extrapyramidal side effects (EPS) had been suggested in animal models as well as in preliminary clinical studies with limited subjects. 2. This study explored the relationships between blood drug levels and clinical effects and EPS of HL in 48 Chinese acutely exacerbated schizophrenic inpatients. After a single-blind placebo period of one week, the patients were treated with a fixed dose 10 mg of HL for two weeks. Steady-state levels of HL and RH in plasma (n = 48) and in red blood cells (RBC) (n = 37) were measured by high performance liquid chromatography. 3. The mean RH/HL ratio in RBC in the Chinese (0.55) is lower than that in non-Chinese patients as reported in the literature (> 2), so is the RH/HL ratios in plasma. 4. No significant relationship emerged between percent improvement in BPRS total score and any of drug indices (HL, RH, sum of two compounds (HL+RH), and RH/HL ratio) in plasma and in RBC. Furthermore, the responders did not differ significantly from the nonresponders in each drug index. 5. Plasma RH levels were significantly higher in 30 patients experiencing EPS compared with the other 18 patients (mean 2.14 +/- 1.71 (S.D.) ng/ml vs. 1.38 +/- 0.37 ng/ml, p < 0.05). No significant differences in other drug indices were noted between subjects with or without EPS.

Value of somatostatin receptor scintigraphy: a prospective study in gastrinoma of its effect on clinical management

BACKGROUND & AIMS

Recently [111In-DTPA-D-Phe1]-octreotide was approved for somatostatin receptor scintigraphy (SRS) of gastroenteropancreatic tumors. SRS and other tumor localization methods can be time consuming, expensive, and involve patient inconvenience. The role of SRS in comparison to other tumor localization modalities remains undefined because the relative effects of these methods on management have not been studied. The aim of this study was to determine whether SRS alters clinical management in Zollinger-Ellison syndrome.

METHODS

One hundred twenty-two consecutive patients were studied prospectively. Each patient was assigned to one of five different clinical categories. Conventional imaging studies (ultrasonography, computerized tomography, magnetic resonance image, angiography, and bone scan) were performed, and the management was proposed. SRS was then performed. Clinical management was reassessed, and whether SRS altered management was determined based on six criteria.

RESULTS

SRS was superior to any single imaging study. SRS altered management in 47% overall and in 22%-60% of patients in the five different clinical categories. Primary tumor localization and clarification of equivocal localization results from conventional studies were the principal reasons for altering management. SRS was equally useful in patients with or without metastatic liver disease.

CONCLUSIONS

Because of the ability of SRS to alter clinical management combined with its superior sensitivity, high specificity, simplicity, and cost-effectiveness, SRS should be the initial imaging modality for patients with gastrinomas.

The binge eating and emotional change in a patient with postinfectious encephalomyelitis

Postinfectious encephalomyelitis is a kind of demyelinating disease with pathological characteristics and a monophasic clinical course. Herein, we describe a patient who had the symptoms of binge eating, fatigue, memory impairment, hypotalkativeness, hypoactivity, lethargy, incoherent speech, dysphoric mood, and episodic disorientation. Only elevation of CSF protein was noted upon initial admission; however, blurred vision of the eyes developed progressively after discharge. A magnetic resonance image (MRI) scanning of the brain demonstrated scattered lesions of low signal intensity on T1-weighted images and high areas on T2-weighted images in the left thalamus, bilateral hypothalamus and midbrain. The findings of MRI image, CSF, and clinical course all suggested postinfectious encephalomyelitis. After a treatment of prednisolone, a follow-up MRI revealed evidence of improvement, and the binge eating also improved.

Urine lipids in patients with a history of filariasis

The presence of lipids in postprandial urine was assessed in 116 patients with a history of filariasis and 70 normal individuals using a biochemical autoanalyzer. Urinary triglycerides (TGs) ranging from 10 to 1955 mg/dl were detected in 13 individuals with a history of chyluria, including 3 with TG levels ranging from 233 to 1955 mg/dl and cholesterol levels of 6-35 mg/dl. Three patients who had a filarial history but without chyluria were also found to have urinary TGs (13-15 mg/dl) without detectable cholesterol. Neither TGs nor cholesterol were detected in the urine of normal individuals. Fluctuations in postprandial urine lipid contents were measured by time course determinations of urinary TG and cholesterol in 17 patients with filariasis and a history of chyluria, 16 patients with filariasis and hydrocele and 16 normal individuals. The level of urine lipid excretion was found to increase within 1-4 h postprandially, with urinary TG levels ranging between 7.8 and 1284 mg/h in eight patients and urinary cholesterol levels between 1.2 and 138 mg/h in seven patients with a history of chyluria. To evaluate the origin of the urine lipids in hematochyluria, fish oil containing 360 mg eicosapentaenoic acid (EPA) and 240 mg docosahexaenoic acid (DHA) was prescribed to a patient with hematochyluria. The excretion of EPA and DHA in urine was increased postprandially in the patient, similar to the elevation of urinary TG and cholesterol. The profile of fatty acids from urine samples showed it was of dietary origin. Our results suggest that postprandial urine lipids, especially TG, might be used as markers for the clinical evaluation of chyluria.

Lipoblastomatosis in a newborn: case report

A male newborn had a well-circumscribed, solid mass on the right anterior chest wall at birth. Computed tomography disclosed an infiltrating soft-tissue mass over the right 6th to 9th ribs near the costochondral junction. Surgical excision was done at the age of 5 days. Pathologic examination showed lipoblastomatosis.

Human Taenia eggs develop into cysticerci in scid mice

The intermediate hosts for Taenia saginata and T. solium are cattle and pigs (and humans for the latter), respectively. In vitro-hatched (but not activated) oncospheres of both Asian Taenia (T. saginata asiatica, a new subspecies of T. saginata or T. asiatica, a new species) and T. solium injected subcutaneously into the backs of mice with severe combined immunodeficiency (scid) developed into fully matured cysticerci. Five-month-old metacestodes of Asian Taenia had no hooklets and were bigger in size than those previously reported and similar to those of T. saginata. Their morphology suggested that the cysticerci were more advanced than those in the intermediate host animals. It is suggested that scid mice are valuable experimental animal models for studying human taeniid cestode infections.

Elimination of the hydrolytic water molecule in a class A beta-lactamase mutant: crystal structure and kinetics

Two site-directed mutant enzymes of the class A beta-lactamase from Staphylococcus aureus PC1 were produced with the goal of blocking the site that in the native enzyme is occupied by the proposed hydrolytic water molecule. The crystal structures of these two mutant enzymes, N170Q and N170M, have been determined and refined at 2.2 and 2.0 A, respectively. They reveal that the side chain of Gln 170 displaces the water molecule, whereas that of Met170 does not. In both cases, the catalytic rates with benzylpenicillin are reduced by 10(4) compared with the native enzyme. With nitrocefin, the N170Q mutant enzyme exhibits an approximately 800-fold reduced rate compared with the native enzyme and in addition, a fast initial burst with stoichiometry of 1 mol of degraded nitrocefin/mol of enzyme. Stopped-flow kinetic experiments establish that the rate constant of the burst is 250 s-1, a value comparable with the rate of acylation of the native enzyme. Two structurally based mechanisms that explain the kinetic properties of the N170Q beta-lactamase are proposed, both invoking a deacylation-impaired enzyme due to the elimination of the hydrolytic water molecule. The catalytic rate of the N170M mutant enzyme with nitrocefin is reduced by approximately 50-fold compared with the native enzyme, and the slow progressive inhibition that is revealed indicates that the hydrolysis proceeds via a branched pathway mechanism. This is consistent with the structural data that show that the water site is preserved and that Met170 occupies part of the space that is required for substrate binding. The short contacts between the substrate and the enzyme may lead to structure perturbation and inactivation.

Intentional replantation of a mandibular molar with calcified canal: a case report

Intentional replantation is an accepted endodontic technique for treating teeth in which both conventional and/or surgical endodontic treatments are not recommended. A rare case using intentional replantation technique on one mandibular molar has been successfully treated. This procedure was used owing to inaccessible calcified canal and pain intolerance of the patient. A thirty month post-operative evaluation revealed an asymptomatic, functional tooth with no radiographic signs of pathosis. The favorable results obtained in this case might be attributed to certain factors, such as occlusal adjustment prior to replantation, maintaining asepsis during replantation, no-damaging pressure during extraction, use of noneugenol periodontal packing, preservation of the vitality of the periodontal ligament, a minimal extraoral period, non-rigid splinting, apicoectomy and retrograde amalgam filling were done for hermetic apical seal. Intentional replantation may be limited to those cases when conventional endodontic therapy is not possible, but may be a treatment alternative to maintain the dentition and save an otherwise hopeless tooth.

The comparative potency of intravenous nicardipine and verapamil on the cardiovascular response to tracheal intubation

BACKGROUND

Two different types of calcium channel blockers (namely nicardipine and verapamil) have been used widely in clinical practice. However, no clinical studies have previously been performed to ascertain the relative potency of intravenous verapamil and nicardipine in the attenuation of cardiovascular response to tracheal intubation.

METHODS

We assessed the optimal dose and relative potency of verapamil and nicardipine in the attenuation of hemodynamic response to tracheal intubation in 135 healthy patients. Control group (Group D received normal saline i.v. Patients in Groups II-V received nicardipine 0.005, 0.01, 0.03 and 0.06 mg/kg i.v., respectively. Patients in Groups VI-IX received verapamil 0.03, 0.05, 0.1 and 0.15 mg/kg i.v., respectively. Anaesthesia was induced with propofol (2.5 mg/kg) and muscle relaxation was facilitated by vecuronium (0.2 mg/kg, i.v.). One min after induction, tracheal intubation was performed. Mean arterial pressure (MAP) was measured at 1 min interval from 10 min before induction to 15 min after induction.

RESULTS

The ED50 with 95% confidence interval of nicardipine and verapamil for the attenuation of 50% mean arterial pressure (MAP) increase after tracheal intubation were 14.55 micrograms/kg (8.25-25.67) and 75.4 micrograms/kg (58.7-96.95), respectively. The ED50 with 95% confidence interval of verapamil for the reduction of the 50% heart rate (HR) increase post tracheal intubation was 57.4 micrograms/kg (18-182.2). No differences were found in the frequency of perioperative arrhythmia, post-operative hypotension, postoperative emesis, dizziness, muscle weakness and muscle soreness within two hours following surgery, when compared control with experimental groups (p > 0.05).

CONCLUSIONS

These results suggest that verapamil and nicardipine attenuate the hypertensive response to tracheal intubation without significant adverse effects in healthy patients. The dose ratio (ED50 nicardipine and ED50 verapamil for MAP) with 95% confidence interval was revealed to be 2.3 (1.82-7.41).

Antiplatelet arylnaphthalide lignans from Justicia procumbens

Fractionation of the EtOH extract of Justicia procumbens, guided by antiplatelet bioassay, led to the isolation of nine known arylnaphthalide lignans, neojusticin A (1), justicidin B (2), justicidin A (3), taiwanin E methyl ether (4), neojusticin B (5), chinensinaphthol methyl ether (6), taiwanin E (8), chinensinaphthol (9), and diphyllin (10), and a new arylnaphthalide lignan that was characterized by spectral means as 4'-demethylchinensinaphthol methyl ether (7). Compounds 1, 2, 4, and 8 significantly inhibited platelet aggregation.

Comparison of continuous step-and-shoot versus step-and-shoot acquisition SPECT

This study compared the quality of SPECT images obtained with step-and-shoot mode (SSM) and continuous step-and-shoot mode (CSSM).

METHODS

Computer simulations of SSM and CSSM were performed with a two-dimensional Shepp-Logan head phantom and a high-resolution parallel-hole collimator. The effects of noise and photon attenuation were examined.

RESULTS

Without noise and without attenuation, small structures in reconstructed images obtained using fast CSSM (less than 4 sec per view plus the moving time from one view to the next) were slightly blurred and rotated in the opposite direction of detector motion. With both noise and attenuation, these artifacts were not visible, and the image quality obtained from CSSM, especially from fast CSSM, was improved as compared to that resulting from the corresponding SSM due to the increasing number of counts. The improvement of image quality became less significant with increasing acquisition time and in the presence of attenuation.

CONCLUSION

For fast SPECT, CSSM provided better image quality than the corresponding SSM, especially when attenuation effects were not present. For relatively long time SPECT without attenuation compensation that is typical for clinical studies, the image quality of CSSM was similar to that of SSM.

Experience with distal circular myotomy for long-gap esophageal atresia

From 1980 to 1994, the authors treated 65 cases of esophageal atresia (with or without tracheoesophageal fistula). Among these patients, 15 (23%) underwent pure proximal circular myotomies and five (8%) underwent both proximal and distal circular myotomies. Of the latter five cases, three were Gross type C and two were Gross type A. The gap ranged from 4.5 cm to 6.5 cm (mean, 5 cm). Surgical complications in these five patients included two anastomotic leaks (40%), one anastomotic stricture (20%), and four gastroesophageal refluxes (80%). Three patients eventually underwent fundoplication as an antireflux procedure. Mucosal outpouching was noted in all cases. The myotomy did not adversely affect the esophageal peristalsis and motility on the esophagogram. Esophageal function was similar to that of other children who had esophageal atresia without myotomy. All patients could eat food typical for their age. This limited experience suggests that distal circular myotomy might be a safe adjuvant procedure to achieve primary anastomosis in long-gap esophageal atresia.

Parathyroid adenomas in the aortopulmonary window

PURPOSE

To describe localization studies in nine patients with ectopic parathyroid adenomas in the aortopulmonary window.

MATERIALS AND METHODS

Nine patients with ectopic parathyroid tissue (eight adenomas, one hyperplastic gland) in the aortopulmonary window were examined with ultrasound (US), computed tomography (CT), magnetic resonance (MR) imaging, and scintigraphy. Diagnostic arteriography (n = 4) and venous sampling (n = 3) were performed in the first four patients; arteriography for the purpose of staining was attempted in the last five patients.

RESULTS

The results of CT and MR imaging studies were positive in eight of nine patients (89%) and five of eight patients (63%), respectively. The results of thallium/technetium scintigraphy were negative in three patients scanned (0%), but the results of a repeat study in one patient were positive (33%). Sestamibi scans were positive in six of six patients (100%). Single photon emission CT was performed in all six patients and enabled distinction between adenomas in the aortopulmonary window and those in the thymus.

CONCLUSION

Ectopic parathyroid glands in the aortopulmonary window are usually detected at sestamibi scintigraphy, and SPECT is helpful in distinguishing these adenomas from more common adenomas in the anterior mediastinum. CT and MR imaging studies can also enable this distinction, but imaging must extend below the aortic arch.

Phantom evaluation of simultaneous thallium-201/technetium-99m aquisition in single-photon emission tomography

This study investigated downscatter effects in cardiac single-photon emission tomographic studies with simultaneous thallium-201/technetium-99m acquisition, and evaluated a previously proposed subtraction technique for downscatter compensation. Ten studies were carried out with different defect sizes and locations and varying activity distributions using four energy windows: 70+/-10% keV, 140+/-10% keV, 100+/-10% KeV, and 103+/-16% keV. The subtraction technique used the 100- or 103-keV data to remove scattered 99mTc counts from the 70-keV data. The size and contrast of infarcts in the dual-isotope 70-keV image were artificially decreased compared to those in the 140-keV image, caused by scattered 99mTc counts that were comparable to the primary 201Tl counts in the 70-keV window. The subtraction technique produced larger defects and more heterogeneous activity in the myocardial wall in dual-isotope 70-keV images compared to the corresponding 201Tl-only images. These artifacts were caused by the markedly different spatial distributions of scattered 99mTc counts in the 100-keV (or 103-keV) window as compared with the 70-keV window. It is concluded that scattered 99mTc photons may cause overestimation of ischemia and myocardial viability in simultaneous dual-isotope patient studies. The proposed subtraction technique was inaccurate and produced image artifacts. Adequate downscatter compensation methods must be developed before applying simultaneous 201Tl/99mTc acquisition in clinical practice.

Effects of Microstop-treated anti-mite bedding on children with mite-sensitive asthma

Seventy-one children with mite-sensitive asthma were randomly divided into three groups. Group 1 was comprised of 28 patients who were provided with new Microstop-treated bedding including matresses, quilts, pillows, bed linens and quilt covers. The Microstop mattresses and pillows were made of impermeable Polyurethane coated nylon ticking. Group 2 included 28 patients who were provided with new, conventional, mat Polyurethane mattresses, quilts, pillows, bed linens and quilt covers made of cotton and polyester which had not been Microstop treated. Group 3 included 15 patients who used their old bedding. Mite counts were performed on samples of dust collected from the old mattresses, pillows and quilts before the bedding was changed. After changing the bedding, mite counts were performed on dust from the same three bed sites at the end of months 1, 2, 3, 6, 9, and 12. Morning and evening peak expiratory flow, asthma symptom scores, were recorded by each patient at least 1 month before entering the study and every month during the one-year study period. Mattress mite counts were significantly reduced in Group 1 but not in Groups 2 or 3. However, quilt mite counts were significantly reduced in both Group 1 and Group 2 throughout the 12-monthstudy while mite counts in Group 3 quilts remained unchanged. The results provide evidence that the PU-coated nylon material was effective in reducing house dust mites, but do not demonstrate that the Microstop treatment had an obvious anti-mite effect. One-year follow-up of asthma symptom scores showed significant improvement in Group 1, but not in Groups 2 or 3. This suggests that the Microstop-treated bedding, as a system, was effective in asthma prevention.