Laser Doppler flux-metry in laryngeal squamous cell carcinoma

Tumour angiogenesis has recently attracted a great deal of attention as a critical part of oncogenesis and a necessary prerequisite for a malignant phenotype. Novel antiangiogenic therapy for solid tumours including laryngeal cancer is entering clinical trials. Quantifying microvessel density is considered the gold standard for measuring baseline angiogenesis and indeed 'the response to intervention'. We hypothesize that laser Doppler flux-metry could provide a non-invasive reliable method of quantifying blood flux within tumours. The aims were to determine whether a laser Doppler flux meter could be used as a reliable and reproducible method of estimating blood flux in the human larynx and to establish baseline Doppler flux recordings for the human larynx. The method used was a validation study in patients with laryngeal squamous cell cancer and normal controls. Statistical analysis was performed using SPSS software. We have demonstrated good reproducibility of laser Doppler measurements in human laryngeal mucosa (correlation coefficient 0.956 @P = 0.01). We have also derived arbitrary means of laser Doppler flux-metry in normal laryngeal mucosa and in squamous cell carcinoma of the larynx. Comparisons between normal and tumour laser Doppler flux-metry (LDF) readings showed no significant difference. We suggest that Laser Doppler flux-metry is a potentially useful tool with which to study blood flow in the larynx and propose arbitrary LDF levels for the normal and diseased human larynx.

[Job satisfaction in rehabilitation clinics--Development of the "MiZu-Reha" questionnaire and its use in quality assurance]

In this study, we report on the development and validation of a questionnaire measuring job satisfaction in rehabilitation centres. The questionnaire "Fragebogen zur Mitarbeiterzufriedenheit in Rehabilitationskliniken" ("MiZu-Reha") consists of 75 items. Three scales measure work climate, leadership and work organisation/communication. Further items assess weak points of work organisation and job satisfaction with several predefined aspects (e. g., career opportunities and salary). The scales have good internal consistency with Cronbach's alpha between 0.86 and 0.94. The dimensionality of the scales was established by confirmatory factor analyses. Correlations between the MiZu-Reha scales and independent satisfaction measures indicate the validity of the questionnaire. Correlations between the MiZu-Reha scales and indicators of patient satisfaction, process quality and outcome are in all cases positive (the higher the job satisfaction, the better the quality of rehabilitation), though weak and statistically not significant. Rehabilitation centres differ clearly from each other regarding job satisfaction of their employees. This shows the usefulness of clinic comparisons based on the MiZu-Reha. The questionnaire can be utilized in external quality assurance programmes, in the context of internal quality assurance measures (e. g. the Business Excellence Model of the European Foundation of Quality Management, EFQM) and in the use of management instruments such as the Balanced Scorecard.

Evidence for Ionic Bonding in YH(3-delta)

The infrared transmission spectra of YH(3-delta) and YD(3-delta) thin films have been measured in the energy range from 300 to 6000 cm(-1), and the optical constants have been calculated by Kramers-Kronig analysis. From a fit of the frequency-dependent conductivity and the dielectric loss functions with one Drude term and five Lorentz oscillators, the longitudinal and transverse optical-phonon frequencies have been determined. The Born and Szigeti effective charges have been calculated and the ionicities of the ions in YH(3-delta) have been derived. We find that hydrogen does not enter as a proton in the compound, but that it is negatively charged, with a Szigeti effective charge of nearly 0.5e.

Idiopathic lymphoepithelial cyst of the parapharynx masquerading as peritonsillar abscess

We present a case of a 38-year-old man who was referred to us with a right-sided quinsy. However he was found to have a large lympho-epithelial cyst in his right parapharynx mimicking the signs of a quinsy to the unsuspecting eye. We describe this case to illustrate an unusual cause of a swelling of the lateral pharyngeal wall.

Signal transduction by human-restricted Fc gamma RIIa involves three distinct cytoplasmic kinase families leading to phagocytosis

Recent experiments indicate an important role for Src family and Syk protein tyrosine kinases and phosphatidylinositol 3-kinase in the signal transduction process initiated by mouse receptors for IgG and leading to phagocytosis. Considerably less is known regarding signal transduction by the human-restricted IgG receptor, FcgammaRIIa. Furthermore, the relationship among the Src family, Syk, and phosphatidylinositol 3-kinase in phagocytosis is not understood. Here, we show that FcgammaRIIa is phosphorylated by an Src family member, which results in recruitment and concomitant activation of the distal enzymes Syk and phosphatidylinositol 3-kinase. Using a FcgammaRI-p85 receptor chimera cotransfected with kinase-inactive mutants of Syk or application of a pharmacological inhibitor of Syk, we show that Syk acts in parallel with phosphatidylinositol 3-kinase. Our results indicate that FcgammaRIIa-initiated monocyte or neutrophil phagocytosis proceeds from the clustered IgG receptor to Src to phosphatidylinositol 3-kinase and Syk.

Caustic soda ingestion -- a case presentation and review of the literature

We present a case report of a 2-year-old child with a hypopharyngeal stricture secondary to caustic soda ingestion. We discuss the initial and long-term management of caustic soda ingestion. In this case the hypopharynx was successfully reconstructed using a pedicled pectoralis major flap. We demonstrate the versatility of this flap, which is traditionally known for its use in adult head and neck surgery.

Chronic bacterial rhinosinusitis: description of a mouse model

OBJECTIVES

To survey normal murine sinonasal anatomy and to create a mouse model for chronic bacterial rhinosinusitis.

DESIGN

Anatomic, histologic, and pathophysiologic study displaying normal murine sinonasal anatomy and surgically created unilateral sinonasal inflammation.

SUBJECTS

Twenty-one 6-week-old, male C57BL/6 mice.

INTERVENTIONS

Animals that underwent unilateral maxillary sinus ostial obstruction using Merocel nasal packing, animals with unilateral Bacteroides fragilis inoculation alone, and animals with both ostial obstruction and bacterial inoculation were examined at 4 weeks for histologic evidence of chronic sinonasal inflammation. Experimental interventions were compared with contralateral control sinuses within each animal and with normal and sham-operated controls.

RESULTS

Normal mouse paranasal sinuses include maxillary sinuses, ethmoid air cells, and respiratory-type epithelium. In experimental animals, the lateral maxillary sinus wall, nasal septum, and superior turbinelle of the maxillary sinus were examined histologically. Epithelial thickening and disarray, goblet cell hyperplasia, inflammatory infiltrates, and sinonasal fibrosis were present in the experimental sinuses of animals packed with Merocel alone or Merocel with bacterial inoculation. Changes seen with Merocel and bacteria were more dramatic than those with Merocel alone. Sham-operated controls and sinuses inoculated with bacteria alone did not differ significantly from the sinuses of normal animals.

CONCLUSION

Unilateral maxillary sinus ostial obstruction using Merocel nasal packing along with B fragilis inoculation results in a persistent, localized bacterial rhinosinusitis in mice.

Mouse connexin 45: genomic cloning and exon usage

Connexin 45 is a gap junction protein that is prominent in early embryos and is widely expressed in many mature cell types. To elucidate its gene structure, expression, and regulation, we isolated mouse Cx45 genomic clones. Alignment of the genomic DNA and cDNA sequences revealed the presence of three exons and two introns. The first two exons contained only 5' untranslated sequences, while exon 3 contained the remaining 5' UTR, the entire coding region, and the 3' UTR. An RT-PCR with exon-specific primers was utilized to examine exon usage in F9 mouse embryonal carcinoma cells and adult mouse tissues. In all samples, PCR products amplified using exon 2/exon 3 or exon 3/exon 3 primer pairs were much more abundant than products produced using exon 1/exon 2 or exon 1/exon 3 primer pairs, suggesting that Cx45 mRNAs containing exon 1 were relatively rare compared with mRNAs containing the other exons. Rapid amplification of cDNA ends (5'-RACE) was performed using antisense primers from within exon 3 and template RNA prepared from F9 cells or from adult mouse kidney. We obtained multiple RACE products from both templates, including products that contained all three exons and were spliced identically to the cDNA. However, clones were also isolated (from kidney) that began within the region previously identified as intron 1 and continued upstream with a sequence identical to the cDNA, including splicing to exon 3. These results show that mouse Cx45 has a gene structure that differs from that of previously studied connexins and allows the production of heterogeneous Cx45 mRNAs with differing 5' UTRs. These differences might contribute to regulation of Cx45 protein levels by modulating mRNA stability or translational efficiency.

Human papillomavirus infection in "young" versus "old" patients with squamous cell carcinoma of the head and neck

BACKGROUND

Human papillomavirus (HPV) represents a potential risk factor for squamous cell cancer of the head and neck (SCCHN). We evaluated the prevalence of HPV DNA in patients with SCCHN diagnosed at the University of Michigan from 1994-1996.

METHODS

Patients were stratified by age at diagnosis as "young" (<50 years; median, 39) or "old" (>50 years; median, 66). Fourteen "young" and 14 "old" were matched for tumor site, and 4 additional "old" patients were included. Specimens were analyzed by polymerase chain reaction for HPV DNA using 2 sets of consensus primers. HPV sequences were confirmed by Southern blot hybridization and typed with type-specific probes.

RESULTS

Overall, 15 of 32 (46.9%) samples contained HPV sequences. HPV 16 was detected in 9 of 15 (60%), HPV-18 in 1 of 15 (6.6%), and 5 of 15 (33.3%) remained untyped by multiple methods. When stratified, 7 of 14 (50%) "young" were HPV-positive compared with 8 of 18 (44.4%) "old" (p =.76). Survival in patients with HPV-positive SCCHN was significantly longer than that for HPV-negative patients.

CONCLUSIONS

The incidence of HPV in "young" versus "old" is not significantly different, suggesting similar roles for both groups. Patients with HPV-positive tumors may have a survival advantage relative to patients with HPV-negative tumors.

Metal ions and human sperm mannose receptors

Zinc and lead concentrations were measured in seminal plasma from fertile donors, infertile men with varicocoele and men undergoing work-ups for in vitro fertilization. Ejaculated spermatozoa from these subjects were incubated in vitro with various metal ions and/or dibromoethane and dibromochloropropane. Mannose receptor expression was correlated with metal and toxicant levels. Sperm distributions of potassium channels were compared with lead ions and calcium channels with zinc ions. Mannose receptor expression by capacitated spermatozoa increased linearly with seminal plasma zinc levels, and correlated inversely with lead levels. Cobalt had no effect on mannose receptor expression, but nickel had a concentration-dependent biphasic effect. Mannose receptor expression was not affected by dibromoethane and dibromochloropropane if the cholesterol content of the sperm membrane was high, but mannose receptor expression was decreased in low cholesterol spermatozoa by exposures below estimated permissive exposure limits. Potassium channels and lead ions co-localized over the entire head of human spermatozoa, while both calcium channels and zinc ions were confined to the equatorial segment of the head. Mannose receptor expression on the external surface of the human sperm plasma membrane is a biomarker for the effects of transition and heavy metals and organic toxicants on sperm fertility potential.

Enzymatic activity of the Src homology 2 domain-containing inositol phosphatase is regulated by a plasma membrane location

The negative regulatory role of the Src homology 2 domain-containing inositol 5-phosphatase (SHIP) has been invoked in a variety of receptor-mediated signaling pathways. In B lymphocytes, co-clustering of antigen receptor surface immunoglobulin with FcgammaRIIb promotes the negative effects of SHIP, but how SHIP activity is regulated is unknown. To explore this issue, we investigated the effect of SHIP phosphorylation, receptor tyrosine engagement by its Src homology 2 domain, and membrane recruitment of SHIP on its enzymatic activity. We examined two SHIP phosphorylation kinase candidates, Lyn and Syk, and observed that the Src protein-tyrosine kinase, Lyn is far superior to Syk in its ability to phosphorylate SHIP both in vitro and in vivo. However, we found a minimal effect of phosphorylation or receptor tyrosine engagement of SHIP on its enzymatic activity, whereas membrane localization of SHIP significantly reduced cellular phosphatidylinositol 3,4, 5-triphosphate levels. Based on our results, we propose that a membrane localization of SHIP is the crucial event in the induction of its phosphatase effects.

Molecular characterization of a voltage-gated potassium channel expressed in rat testis

Potassium (K(+)) channels are present in both mammalian testis and spermatozoa. Immunofluorescent detection of sperm-bound biotinylated charybdotoxin, an inhibitor of Ca(2+)-activated and of delayed rectifier K(+) channels, indicated that these ion channels are uniformly distributed over the surface of both heads and tails of unfixed rat epididymal spermatozoa. Reverse transcription-polymerase chain reaction (RT-PCR) analysis on rat testis RNA with PCR primers, based on known nucleotide sequences of different classes of K(+) channels, amplified sequences homologous to delayed rectifier K(+) channels. In-situ RT-PCR on rat testis sections showed that these K(+) channel transcripts are present in the cytoplasm of primary spermatocytes and post-meiotic elongating spermatids. Northern blot analysis of various rat tissues identified multiple K(+) channel transcripts, some of which were observed only in testis. An attempt to obtain a full length rat testis K(+) channel cDNA sequence gave an assembled sequence of 2693 base pairs with >90% homology to a delayed rectifier K(+) channel, Kv1.3. A method for rapid amplification of cDNA ends was employed to amplify the 5' sequences of the rat testis cDNA but a unique sequence could not be obtained. DNA sequencer traces suggest that multiple related K(+) channels which differed at their 5' ends were amplified in rat testis.

Male infertility and environmental exposure to lead and cadmium

Humans are exposed occupationally and environmentally to metal aerosols including lead (Pb2+) and cadmium (Cd2+). These toxicants accumulate in male reproductive organs. Epidemiological studies have been equivocal about effects of Pb2+ and Cd2+ on hormone concentrations, male fertility and sperm parameters. Comparison of Pb2+ and Cd2+ concentrations in fertile and infertile men are problematic. Problem areas include failure to control confounding variables, but genetic polymorphisms as in somatic diseases may modulate Pb2+ and Cd2+ damage. Multiple calcium (Ca2+) and potassium (K+) channel isoforms have been identified in human testes and spermatozoa. These Ca2+ and K+ channels are involved in early events of acrosome reactions. Ca2+ channel are susceptible to Cd2+ poisoning and K+ channels to Pb2+. These channels offer entry paths for metallic toxicants into mature spermatozoa. Ion channel polymorphisms may cause differential sensitivities to Cd2+ and Pb2+, explaining in part prospective blinded studies showing high Cd2+ in varicocele-related human infertility and high Pb2+ in unexplained infertility. In both forms of male infertility the ability to undergo an acrosome reaction decreases. Reverse transcriptase-polymerase chain reaction assays for Ca2+ and K+ channel isoforms may identify susceptibility subgroups with lower resistance to environmental exposures.

Single-or-two-stage laryngotracheal reconstruction; comparison of outcomes

To compare single-stage laryngotracheal reconstruction (SSLTR) and reconstruction with tracheostomy and indwelling stent (two-stage LTR), a retrospective review was made of 69 patients undergoing laryngotracheal reconstruction for subglottic stenosis at Great Ormond Street Hospital for Sick Children. Pre-operative details recorded included grade and aetiology of subglottic stenosis, history of previous laryngeal surgery, sex of patient and age at reconstruction. As a measure of outcome, the total number of procedures including all endoscopy and further reconstruction was recorded as well as de-cannulation rate, and the need for more than one reconstruction. The patients undergoing two-stage reconstruction tended to have more severe stenosis (mean grade = 2.56) compared to the SSLTR group (mean grade = 2.14) and were more likely to have had previous laryngeal surgery. Inevitably, the outcome after reconstruction in the two-stage patients is therefore less favourable, and direct comparison of the two groups is not statistically valid. However, multiple regression analysis reveals that single-stage reconstruction does confer a significant independent advantage over the two-stage procedure in terms of average number of post reconstruction procedures (p = 0.006), and a significant advantage in de-cannulation rate (p = 0.03). No difference was noted in the requirement for further reconstruction between the two groups. Although a two-stage procedure is still required in certain cases such as those with very severe stenosis or respiratory insufficiency, the single-stage reconstruction is the procedure of choice for uncomplicated paediatric subglottic stenosis.

Standardization of creatine kinase-MB (CK-MB) mass assays: the use of recombinant CK-MB as a reference material

BACKGROUND

The AACC assembled a committee to identify and validate a standard creatine kinase MB isoenzyme (CK-MB) material to improve the comparability of CK-MB mass assays.

METHODS

Three protocols were used. In protocol I, various CK-MB materials prepared in different matrices were screened as candidate standards. In protocol II, participating manufacturers calibrated their systems with concentrates of human heart CK-MB and then tested 20 patient samples to evaluate calibration bias. In protocol III, participating manufacturers calibrated their immunoassay systems using recombinant CK-MB2 (rCK-MB2) diluted into their respective sample diluents and measured 50 samples.

RESULTS

Candidate materials showed high recovery in stripped human serum, but bias improved only from 59% to 38%. These data led to the use of human heart CK-MB diluted in each manufacturer's sample diluent. This strategy reduced bias from 31% to 15%. Because human heart CK-MB is difficult to provide, a lyophilized source of CK-MB2 was identified. rCK-MB2 was shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, reversed-phase HPLC, intrinsic protein fluorescence, circular dichroism, agarose gel electrophoresis, immunoreactivity studies, high and low temperature stability, and reconstituted stability to be equivalent to human heart CK-MB. Calibration of immunoassay systems with rCK-MB2 added into each respective manufacturer's sample diluent showed a 13% between-manufacturer bias.

CONCLUSION

Lyophilized rCK-MB2 was determined suitable for use as a reference material for CK-MB mass assays.

The HNF-3alpha transcription factor is a primary target for retinoic acid action

We have previously demonstrated that gene expression of the hepatocyte nuclear factor 3alpha (HNF-3alpha) transcription factor is activated during retinoic-acid-induced differentiation of F9 embryonal carcinoma cells (A. Jacob et al. (1994). Nucleic Acids Res. 22, 2126-2133). We have extended these studies and now show that HNF-3alpha mRNA is induced approximately 6 h after addition of retinoic acid to the cells, peaks at 1 day postdifferentiation, and then declines to undetectable levels. Furthermore, HNF-3alpha induction occurs in the absence of de novo protein synthesis, suggesting that it is a primary target for retinoic acid action. In order to corroborate this hypothesis, we have mapped the cis-acting HNF-3alpha promoter site that mediates the retinoic acid response. DNA sequence analysis indicates that the HNF-3alpha promoter contains an authentic retinoic acid response element (RARE) of the DR5 class. As expected, this element is able to confer retinoic acid responsiveness to a heterologous promoter. In addition, the HNF-3alpha-specific RARE is able to interact with various retinoic acid receptor heterodimers of the RAR/RXR type. Since HNF-3alpha is induced early during mammalian neurogenesis, our data shed new light on the connection between retinoic-acid-mediated HNF-3alpha activation and establishment of the neuronal phenotype.

Numerical dose-compensated in vitro fertilization inseminations yield high fertilization and pregnancy rates

OBJECTIVE

To evaluate in cases with morphologically abnormal sperm whether fertilization and pregnancy rates are increased by normalizing the number of sperm inseminated and whether biomarkers can identify cases of reduced or failed fertilization.

DESIGN

Prospective studies of sperm morphology and function.

SETTING

University hospital assisted human reproduction program.

PATIENT(S)

Partners of 308 women undergoing IVF.

INTERVENTION(S)

Motile sperm populations were assessed for sperm head morphology, for surface receptors for mannose and progesterone binding, and the ability to undergo a free mannose-induced acrosome reaction. Zinc in seminal plasma was determined by atomic absorption spectroscopy.

MAIN OUTCOME MEASURE(S)

Sperm morphology was associated with fertilization and clinical pregnancy rates. Biomarker analyses were correlated with fertilization rates using Kruskal-Wallis tests, chi2 tests, and Spearman rank order correlations.

RESULT(S)

Fertilization and pregnancy rates after numerical dose compensation inseminations were indistinguishable between men with differing percentages of normal sperm. Biomarker deficits were identified irrespective of sperm head morphology in 96% of cases of reduced or failed fertilization.

CONCLUSION(S)

Fertilization and pregnancy rates in cases of abnormal morphology are optimized by inseminating at least 25,000 sperm/mL with normal acrosomes. Reduced or failed fertilization can be predicted by testing for molecular deficits in mannose receptor expression and mannose-stimulated acrosome loss.

Chronic suppurative otitis media: prevalence and practices among rural South Indian children

In order to determine the prevalence of chronic suppurative otitis media (CSOM) in rural South Indian children, a cross-sectional survey was conducted among 914 children (484 boys and 430 girls) from four primary schools and 12 nurseries (balwadis; preschool), of adjacent villages of North Arcot District of Tamil Nadu state. The preschool children were aged 2-5 years, while the ages of the primary school children ranged from 6 to 10 years. The overall prevalence rate of CSOM was found to be 6%. The disease was equally prevalent in preschool children (5.7%) and primary school children (6.2%) (P = 0.94). Cholesteatomatous ear disease was observed in 1.2% of children, those of the older age group having a slightly higher prevalence rate (1.5%) than the younger age group (0.7%). Parental beliefs and existing practices with respect to the disease are also presented.

FcgammaRIIb modulation of surface immunoglobulin-induced Akt activation in murine B cells

We examined activation of the serine/threonine kinase Akt in the murine B cell line A20. Akt is activated in a phosphoinositide 3-kinase (PtdIns 3-kinase)-dependent manner upon stimulation of the antigen receptor, surface immunoglobulin (sIg). In contrast, Akt induction is reduced upon co-clustering of sIg with the B cell IgG receptor, FcgammaRIIb. Co-clustering of sIg-FcgammaRIIb transmits a dominant negative signal and is associated with reduced accumulation of the PtdIns 3-kinase product phosphatidylinositol 3,4,5-trisphosphate (PtdIns 3,4,5-P3), known to be a potent activator of Akt. PtdIns 3-kinase is activated to the same extent with and without FcgammaRIIb co-ligation, indicating conditions supporting the generation of PtdIns 3,4,5-P3. We hypothesized that the decreased Akt activity arises from the consumption of PtdIns 3,4,5-P3 by the inositol-5-phosphatase Src homology 2-containing inositol 5-phosphatase (SHIP), which has been shown by us to be tyrosine-phosphorylated and associated with FcgammaRIIb when the latter is co-ligated. In direct support of this hypothesis, we report here that Akt induction is greatly reduced in fibroblasts expressing catalytically active but not inactive SHIP. Likewise, the reduction in Akt activity upon sIg-FcgammaRIIb co-clustering is absent from avian B cells lacking expression of SHIP. These findings indicate that SHIP acts as a negative regulator of Akt activation.

Serologic evidence of human monocytic and granulocytic ehrlichiosis in Israel

We conducted a retrospective serosurvey of 1,000 persons in Israel who had fever of undetermined cause to look for Ehrlichia chaffeensis antibodies. Four of five cases with antibodies reactive to E. chaffeensis were diagnosed in the summer, when ticks are more active. All patients had influenzalike symptoms with high fever. None of the cases was fatal. Three serum samples were also seroreactive for antibodies to E. canis, and one was also reactive to the human granulocytic ehrlichiosis (HGE) agent. The titer to the HGE agent in this patient was higher than the serum titer to E. chaffeensis, and the Western blot analysis also indicated that the HGE agent was the primary cause of infection. We present the first serologic evidence that the agents of human monocytic ehrlichiosis (HME) and HGE are present in Israel. Therefore, human ehrlichiosis should be included in the differential diagnoses for persons in Israel who have been exposed to ticks and have influenzalike symptoms.

Modified preparation and rapid quality control test for technetium-99m-tetrofosmin

OBJECTIVE

The objectives of this study were to: modify the preparation of 99mTc-tetrofosmin by using twice the amount of 99mTcO4- recommended by the manufacturer; evaluate the use of miniaturized rapid paper chromatography (MRPC) for quality control (QC) testing; and determine the in vitro stability of the modified preparation using MRPC.

METHODS

Two preparations of 99mTc-tetrofosmin were made: one with 4.4-8.8 GBq (120-240 mCi) and the other with 13.9-17.6 GBq (380-480 mCi) 99mTcO4-, referred to as regular and modified preparations, respectively. Routine QC tests were performed using MRPC and instant thin-layer chromatography/silica-gel (ITLC/SG) systems. The preparations were injected into 58 patients. Planar and SPECT images of stress and rest studies were obtained. The technical quality of the SPECT images was graded visually by four observers. Heart-to-lung and heart-to-background ratios were calculated from the planar images.

RESULTS

The QC testing procedure took 4.18 +/- 0.15 min with MRPC and 54 +/- 5.3 min with ITLC/SG systems. The percent labeling efficiency, as determined by both techniques, ranged from 95.6 +/- 1.6 to 97.2% +/- 0.8%. Both preparations were stable up to 6 hr after reconstitution. There was no difference between the cardiac-to-lung and cardiac-to-background ratios of the two preparations.

CONCLUSION

The results indicate that MRPC is a faster and effective chromatographic technique for routine QC testing of 99mTc-tetrofosmin. Doubling the amount of 99mTcO4- used in preparing 99mTc-tetrofosmin did not affect its in vitro stability, its efficacious use in patients or the technical quality of the images.