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Background: To study the compatibility of cephalosporins with intraocular irrigating solutions and intracameral medications commonly used in cataract surgery. Design: The was an in vitro experiment conducted in the Research Laboratory of the Department of Microbiology, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. Samples: Three cephalosporins – cefazolin, cefuroxime and ceftazidime – were separately diluted and mixed with irrigating solutions and intracameral medications to form 192 samples and 12 control solutions. Methods: The cephalosporins were dissolved in normal saline and further diluted to the concentration of 1 mg in 0.1 mL with normal saline, Ringer's solution, balanced salt solution and fortified balanced salt solutions. These were mixed with balanced salt solutions or fortified balanced salt solutions, with adrenaline, acetylcholine or carbachol and kept at 37°C for 2 h. The concentrations of free cephalosporins were measured with rapid high-performance liquid chromatography at baseline (0 h) and at 2 h. Main Outcome Measures: Free concentrations of cephalosporins at 2 h were compared with mean baseline (0 h) value. A difference of 3 standard deviations or more was considered statistically significant. Results: At 2 h there was a significant drop in the cefuroxime concentration in preparations in which cefuroxime was diluted with normal saline (P

Genomic disorders have been increasingly recognized as a significant source of clinically relevant phenotypes largely fostered by advances in technologies for genome-wide analyses. Molecular and clinical studies of copy number variants involving chromosome 17 began with locus-specific studies of Charcot-Marie-Tooth disease type 1A (CMT1A, OMIM #118220) and hereditary neuropathy with liability to pressure palsies (HNPP, OMIM #162500), which laid the foundation for the paradigm of duplication/deletion and gene-dosage for our understanding of genomic disorders. With the clinical introduction of high-resolution array comparative genomic hybridization (aCGH) the number of recognized genomic disorders including microduplications has been increasing rapidly. A relatively high proportion of disease-associated copy number variants map to chromosome 17. This may result from its unique structural features, such as relative abundance of segmental duplications and interspersed repetitive elements, high gene content, and the presence of dosage-sensitive genes. These genomic rearrangements are mediated by diverse mechanisms including Non-Allelic Homologous Recombination (NAHR), Non-Homologous End-Joining (NHEJ), and Fork Stalling and Template Switching (FoSTeS). We provide specific examples of chromosome 17 microduplications with the emphasis on their phenotype, specific clinical features aiding in their diagnosis, and counseling.

We report on a young male with moderate mental retardation, dysmorphic features, and language delay who is deleted for 7q31.1-7q31.31. His full karyotype is 46,XY,der(7)del(7)(q31.1q31.31)ins(10;7)(q24.3;q31.1q31.31)mat. This child had language impairment, including developmental verbal dyspraxia, but did not meet criteria for autism according to standardized ADOS testing. Our patient's deletion, which is the smallest reported deletion including FOXP2, adds to the body of evidence that supports the role of FOXP2 in speech and language impairment, but not in autism. A reported association between autism and deletions of WNT2, a gene also deleted in our patient, is likewise not supported by our case. Previously, fine mapping with microsatellites markers within in a large three-generation family, in which half the members had severe specific language impairment, aided the localization of the SPCH1 locus to 7q31 within markers D7S2459 (107.1 Mb) and D7S643 (120.5 Mb). Additionally, chromosome rearrangement of 7q31 and mutational analyses have supported the growing evidence that FOXP2, a gene within the SPCH1 region, is involved with speech and language development. It is unclear however whether the AUTS1 (autistic spectrum 1) locus, highly linked to 7q31, overlaps with the SPCH1 and FOXP2.

Wilms tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome is a contiguous gene deletion syndrome involving the Wilms tumor 1 gene (WT1), the paired box gene 6 (PAX6), and possibly other genes on chromosome 11p13. WT1 is required for normal formation of the genitourinary system and the high incidence of Wilms tumor and genitourinary anomalies found in patients with WAGR are attributed to haploinsufficiency of this gene. It has been hypothesized that WT1 also plays an important role in the development of the diaphragm. During mammalian embryonic development, WT1 is expressed in the pleural and abdominal mesothelium that forms part of the diaphragm. Furthermore, mice that are homozygous for a deletion in the mouse homolog of WT1 have diaphragmatic hernias. Case reports describing congenital diaphragmatic hernias in infants with Denys-Drash and Frasier syndromes, both of which can be caused by mutations in WT1, provide additional support for this hypothesis. We report an infant with aniridia, bilateral cryptorchidism, vesicoureteral reflux, and a right-sided Morgagni-type diaphragmatic hernia. G-banded chromosome analysis revealed a deletion of 11p12-p15.1. Breakpoint regions were refined by fluorescence in situ hybridization (FISH) and deletion of the WAGR critical region, including WT1, was confirmed. A review of the medical literature identified a second patient with a deletion of 11p13, a left-sided Bochdalek-type diaphragmatic hernia, and anomalies that suggest a diagnosis of WAGR including bilateral microphthalmia, a small penis, bilateral cryptorchidism, and a hypoplastic scrotum. These cases demonstrate that congenital diaphragmatic hernia can be associated with WAGR syndrome and suggest that deletions of WT1 may predispose individuals to develop congenital diaphragmatic hernia.

We present molecular genetic investigations of a 4-year-old boy with craniofacial dysmorphism and developmental delay. Trivial mitral and tricuspid regurgitation without gross structural abnormality was diagnosed by echocardiography. High-resolution chromosome analysis revealed an interstitial deletion, del(10)(p12.1p12.32). To characterize the deletion size and breakpoints, we performed fluorescence in situ hybridization analysis using 27 BAC clones. Our data demonstrate an approximately 5.5 Mb deletion del(10)(p12.1p12.31). Surprisingly, the BAC clone RP11-56H7 that contains NEBL, an apparent downstream gene of the cardiogenic transcription factor HAND2 previously shown to be deleted in the patients with DiGeorge 2 syndrome and 10p13 deletion, was deleted in our patient with 10p12.1-p12.31 deletion. In addition, we provide clinical data and results of molecular analysis for a patient with multiple congenital anomalies including Ebstein's anomaly, kidney malformations, and 10p13-p14 deletion. We also reviewed 19 patients with congenital heart defects and deletions involving 10p and propose that atrial septal defect (ASD) is a common cardiac anomaly associated with DiGeorge 2 syndrome. Based on genotype-phenotype analysis of published patients and those reported herein, we propose an approximately 1.0 Mb critical region between loci D10S547 and D10S2176 in 10p14 to be associated with ASD. Considering that septal defects are the most frequent congenital heart anomaly, we suggest that further investigations in the 10p critical region are important to identify gene(s) responsible for this common birth defect.

The rapid identification of Mycobacterium tuberculosis complex from 161 consecutive positive Bactec 12B cultures originated from non-respiratory secretion specimens was evaluated by comparing Accuprobe and an in-house polymerase chain reaction method. Using conventional biochemical method as the gold standard, 85.7% of the isolates (n = 138) were identified as Mycobacterium tuberculosis. The sensitivities of Accuprobe and the in-house-polymerase chain reaction method in identifying Mycobacterium tuberculosis complex were 92.0% (127/138) and 93.5% (129/138), respectively. Specificities of both methods being 87.0% (20/23 for both tests). Using a batch system of performing identification once weekly, the average turnaround time for Accuprobe, from the time of primary inoculation, was 27 days, which was comparable with that of in-house polymerase chain reaction, which was 29 days. The average time required for a confirmatory result based on conventional biochemical identification method was 84 days. The estimated reagent cost of in-house polymerase chain reaction was only one-fifth of that of Accuprobe. Therefore, the choice of methodology will depend on the individual laboratory's availability of resources and clinical demand. In the event of discrepant results between rapid identification methods and conventional methods, histological examination and clinical assessment can provide guidance as to the nature of the infection.

Fibreoptic bronchoscopy was performed on 190 patients with chest radiographic lesions and negative sputum smears for acid-fast bacilli. Aside from obtaining transbronchial biopsies for histological examination, bronchial aspirate specimens were also tested for Mycobacterium tuberculosis complex DNA by a conventional polymerase chain reaction (PCR) technique. Of 177 transbronchial biopsies performed, a diagnosis was found in 64 cases [43 cases of tuberculosis (TB), 17 cases of lung carcinoma and four cases of other infective/inflammatory diseases] giving a diagnostic yield of 36·2%. PCR was positive in 105 of 108 finally diagnosed cases of TB and 22 of 82 non-TB cases. The sensitivity, specificity, positive predictive value and negative predictive value of PCR when applied to bronchial aspirate specimens for diagnosing smear-negative pulmonary TB were 97·2%, 73·2%, 82·7% and 95·2% respectively. Therefore, detection of M. tuberculosis complex DNA in bronchial aspirates by PCR might have an adjunctive place to transbronchial biopsies in the rapid diagnosis of smear-negative pulmonary tuberculosis.

We evaluated treatment with linezolid, dosed at 800 mg once daily for 1 to 4 months as guided by sputum culture status and tolerance and then at 1,200 mg thrice weekly until ≥1 year after culture conversion, in addition to individually optimized regimens among 10 consecutive patients with extensively drug-resistant tuberculosis or fluoroquinolone-resistant multidrug-resistant tuberculosis. All achieved stable cure, with anemia corrected and neuropathy stabilized, ameliorated, or avoided after switching to intermittent dosing. Serum linezolid profiles appeared better optimized.

A randomised double-blind controlled clinical trial was conducted to compare oral ciprofloxacin (500 mg b.d.) and amoxycillin (1 g t.d.s.) in the treatment of infective exacerbations of bronchiectasis. The commonest organism isolated from sputum was Pseudomonas aeruginosa, which accounted for 34% of all positive sputum cultures. Other Pseudomonas species and Haemophilus influenzae, accounted for 19%, respectively. Ciprofloxacin produced better clinical response, a higher sputum to serum antibiotic level (mean of 0.65 in the ciprofloxacin group vs. 0.18 in amoxycillin group, p = 0.0001), broader spectrum of antibacterial activity and less side-effect. It was also better tolerated by patients. The findings suggest that ciprofloxacin is an effective treatment of infective exacerbations of bronchiectasis.

Summary Objectives Early diagnosis of smear-negative tuberculosis remains challenging. The role of an interferon-gamma release assay (IGRA) in discriminating active pulmonary tuberculosis (PTB) among cases of ‘pneumonia' was investigated. Methods Consecutive patients admitted to an acute hospital in Hong Kong (intermediate TB burden) during 2006–2008 because of pneumonia and suspected PTB were recruited for IGRA (Quantiferon-TB Gold, QFN-G) study. Diagnosis of tuberculosis was confirmed by mycobacterial culture or histology. Results Altogether 179 patients were recruited (median (IQR) age 59 (44–75), 68.7% male); active PTB was confirmed in 63 (35.2%). Among the AFB-smear-negative ‘pneumonias' ( n = 152), age>50 (OR 0.27, 95% CI 0.09–0.84), absence of weight loss (OR 0.30, 95% CI 0.10–0.88), and negative IGRA (OR 0.08, 95% CI 0.03–0.25) were independently associated with lower risks of PTB. The overall sensitivity, specificity, positive and negative predictive values for the IGRA in diagnosing active PTB were 60%, 87%, 72% and 80% respectively. Among smear-negative ‘pneumonias' ( n = 152), the performance values of IGRA were 64%, 87%, 62% and 88% respectively; in the absence of characteristic clinical or radiographic features of PTB, the negative predictive value (NPV) improved to 90–95%. Conclusions The high NPV of QFN-G among smear-negative ‘pneumonias' can be useful for risk stratification in hospitalized patients suspected of PTB. Further investigation on the role of these assays in patient management is warranted.

Mutations in genes encoding voltage-gated sodium channels are significant factors in the etiology of neurological diseases and psychiatric disorders, including various types of idiopathic epilepsy. Using a clinical exon-targeted oligonucleotide array comparative genomic hybridization (aCGH), we have identified a de novo ~110-kb deletion involving exons 1-2 of SCN2A and non-coding exon 1a of SCN3A in a 25-year-old female with mental retardation, neurobehavioral and psychiatric abnormalities, and a history of infantile seizures with abnormal EEG. We propose that haploinsufficiency of SCN2A may play an important role in the genetic basis of neurodevelopmental and neurobehavioral disorders and emphasize the efficacy of detecting exonic copy-number variation (CNV) by exon-targeted oligo aCGH.

We report an ~1.3 Mb tandem duplication at Xp11.23p11.3 in an 11-year-old boy with pleasant personality, hyperactivity, learning and visual-spatial difficulties, relative microcephaly, long face, stellate iris pattern, and periorbital fullness. This clinical presentation is milder and distinct from that of patients with partially overlapping Xp11.22p11.23 duplications which have been described in males and females with intellectual disability, language delay, autistic behaviors, and seizures. The duplicated region harbors three known X-linked mental retardation genes: FTSJ1, ZNF81, and SYN1. Quantitative polymerase chain reaction from whole blood total RNA showed increased expression of three genes located in the duplicated region: EBP, WDR13, and ZNF81. Thus, over-expression of genes in the interval may contribute to the observed phenotype. Many of the features seen in this patient are present in individuals with Williams-Beuren syndrome (WBS). Interestingly, the SYN1 gene within the duplicated interval, as well as the STX1A gene, within the WBS critical region, co-localize to presynaptic active zones, and play important roles in neurotransmitter release.

Tinnitus is an auditory disorder characterized by perception of internally generated phantom auditory sensations without corresponding mechanical stimuli arising from the body or external environment. Current auditory based treatment approaches, sometimes in conjunction with nonauditory based strategies, such as Tinnitus Retraining Therapy and Cognitive Behavioral Therapy, have been helpful in mitigating symptoms for the majority of patients. Yet there are over 1 million tinnitus sufferers who still endure troublesome chronic, continuous head noises that are debilitating and interfere with activities of daily living. Here we show that application of deep brain stimulation (DBS) therapy to a locus of caudate neurons (area LC) in the body of the nucleus, a subsite of the striatum that is not part of the classical auditory pathway, can decrease or increase tinnitus loudness perception. The DBS lead traversed through or was adjacent to area LC in six Parkinson's disease and essential tremor subjects with concomitant tinnitus who underwent implantation of the subthalamic or ventral intermediate nucleus. In five subjects where the DBS lead tip traversed area LC, tinnitus loudness in both ears was suppressed to a nadir of level 2 or lower on a 0-10 rating scale. In one subject where the DBS lead was outside area LC, tinnitus was not modulated. In three subjects with preoperative and postoperative audiograms, hearing thresholds were unchanged by area LC stimulation. Neuromodulation of area LC may be interrupting perceptual integration of phantom sensations generated in the central auditory system. This new, basal ganglia based approach to tinnitus modulation warrants further investigation and may be ultimately refined to treat patients with refractory symptoms.

Recent advances in molecular cytogenetics enable identification of small chromosomal aberrations that are undetectable by routine chromosome banding in 5-20% of patients with mental retardation/developmental delay (MR/DD) and dysmorphism. The aim of this study was to compare the clinical usefulness of two molecular cytogenetic techniques, metaphase high-resolution comparative genomic hybridization (HR-CGH) and targeted array CGH, also known as Chromosomal Microarray Analysis (CMA). A total of 116 patients with unexplained mild to severe MR and other features suggestive of a chromosomal abnormality with apparently normal or balanced karyotypes were analyzed using HR-CGH (43 patients) and/or CMA (91 patients). Metaphase HR-CGH detected seven interstitial deletions (16.3%). Rare deletions of chromosomes 16 (16p11.2p12.1) and 8 (8q21.11q21.2) were identified. Targeted CMA revealed copy-number changes in 19 of 91 patients (20.8%), among which 11 (11.8%) were clinically relevant, 6 (6.5%) were interpreted as polymorphic variants and 2 (2.1%) were of uncertain significance. The changes varied in size from 0.5 to 12.9 Mb. In summary, our results show that metaphase HR-CGH and array CGH techniques have become important components in cytogenetic diagnostics, particularly for detecting cryptic constitutional chromosome imbalances in patients with MR, in whom the underlying genetic defect is unknown. Additionally, application of both methods together increased the detection rates of genomic imbalances in the tested groups.

In XY males, duplication of any part of the X chromosome except the pseudoautosomal region leads to functional disomy of the corresponding genes. We describe three unrelated male patients with mental retardation (MR), absent or delayed speech, and recurrent infections. Using high-resolution comparative genomic hybridization (HR-CGH), whole genome array comparative genomic hybridization (array CGH), fluorescent in situ hybridization (FISH), and multiplex ligation probe amplification (MLPA), we have identified and characterized two different unbalanced Xq27.3-qter translocations on the Y chromosome (approx. 9 and 12 Mb in size) and one submicroscopic interstitial duplication (approx. 0.3–1.3 Mb) involving the MECP2 gene. Despite the differences in size of the duplicated segments, the patients share a clinical phenotype that overlaps with the features described in patients with MECP2 duplication. Our data confirm previous observations that MECP2 is the most important dosage-sensitive gene responsible for neurologic development in patients with duplications on the distal part of chromosome Xq. © 2007 Wiley-Liss, Inc.

Haploinsufficiency of SOX9, a master gene in chondrogenesis and testis development, leads to the semi-lethal skeletal malformation syndrome campomelic dysplasia (CD), with or without XY sex reversal. We report on two children with CD and a phenotypically normal father, a carrier of a somatic mosaic SOX9 deletion. This is the first report of a mosaic deletion of SOX9; few familial CD cases with germline and somatic mutation mosaicism have been described. Our findings confirm the utility of aCGH and indicate that for a more accurate estimate of the recurrence risk for a completely penetrant autosomal dominant disorder, parental somatic mosaicism should be considered in healthy parents.

Aniridia usually occurs in isolation, but may also occur as part of the WAGR contiguous gene deletion syndrome, which includes Wilms tumor, aniridia, genitourinary abnormalities, and mental retardation. The aniridia and predisposition for Wilms tumor seen in WAGR are caused by haploinsufficiency for PAX 6 and WT1, respectively. We present a female infant with aniridia, bilateral ptosis, bilateral posterior capsular cataracts, nystagmus, left-sided glaucoma, microcephaly, mild unilateral hydronephrosis, poor linear growth, and gross motor delay consistent with a clinical diagnosis of WAGR syndrome. In addition, weight-for-height ratio at 12 months is at the 94th centile, raising the possibility of a diagnosis of WAGRO (WAGR + Obesity). Chromosome analysis revealed a translocation (11;15)(p13;p11.2) which has not been previously associated with a diagnosis of WAGR. Subsequent clinical WAGR fluorescent in situ hybridization (FISH) analysis demonstrated a deletion of 11p13 including PAX6 and WT1. A complete FISH-mapping of the breakpoints on chromosome 11 revealed a 7 Mb deletion within 11p13-11p14. The patient is examined in light of other reported patients with deletions and/or translocations involving the regions between 11p12 --> 11p14 including patients with WAGR + obesity (WAGRO) as well as with other reported patients with aniridia and congenital ptosis.

A rapid non-culture-based diagnostic method utilizing d-/l-arabinitol (DA/LA) ratios as a chemical marker of invasive candidiasis was developed and explored. The enantiomers-ratios detection was made possible by the use of gas chromatography coupled with mass spectrometry (GC/MS). The mean DA/LA ratios +/- standard deviation (range) in urine (n = 40) and serum (n = 20) were 2.08 +/- 0.78 (0.57 to 3.55) and 1.79 +/- 0.75 (0.74 to 3.54), respectively, from patients without evidence of fungal infection or colonization; in patients (n = 7) with culture-proven invasive candida infections, the figures were 9.91 +/- 3.04 (7.24 to 16.27) and 13.58 +/- 7.31 (5.57 to 25.88) in urine and serum, respectively. The differences in DA/LA ratios between the candidemic patients and the non-candidemic patients were statistically significant (p < 0.01) in both serum and urine samples. The DA/LA ratios were not significantly affected in patients with oral or vaginal candidiasis and candiduria.

nancy, and leptin levels have been linked to various pregnancy complications, including gestational diabetes, intrauterine growth restriction and preeclampsia. We sought to characterize methylation patterns in the leptin gene in normal early pregnancy and preeclamptic pregnancies. STUDY DESIGN: The methylation profiles of 2 CpG sites in the leptin gene were characterized in DNA from maternal blood longitudinally in 14 women at 16 gestational weeks, at delivery and postpartum; and in 14 preeclamptics at delivery. All women were non-smokers and the groups were matched for age and BMI. Genomic DNA was derived from buffy coat, purified, and bisulfite modified then run on the Illumina Methylation Assay. Mean methylation levels at each CpG site were compared using a t-test. RESULTS: Leptin methylation patterns at both CpG sites differed significantly between the early pregnancy and postpartum samples (P 0.01, P 10-5). Both leptin CpG sites were hypomethylated during early pregnancy as compared to postpartum. Methylation patterns were similar in normotensive and preeclamptic patients at the time of delivery (P 0.64, P 0.71). CONCLUSION: Our data demonstrates that early pregnancy results in decreased methylation at two CpG sites on the leptin gene. As methylation levels tend to be inversely correlated with gene transcription and resultant serum protein levels, this result suggests that altered methylation may be an epigenetic mechanism to control increased leptin production in normal early pregnancy. The presence of preeclampsia at the time of delivery did not appear to impact methylation of the leptin gene compared to normotensive patients. This suggests that there may be another mechanism controlling the increase in circulating serum leptin seen in pregnancies effected by preeclampsia.

Abstract 2543 aCGH has become the state-of art tool for assaying copy number changes of the entire genome in recent years. It offers a high resolution, high throughput and an unbiased view of detecting copy number changes in a genome compared to standard cytogenetics. In fact, aCGH has become the standard of care for detection of genomic/cytogenetic abnormalities in a postnatal setting recently (PMID # 20466091). In contrast, the application of aCGH in a clinical setting is lagging behind for acquired disease such as cancer, although aCGH has contributed greatly in our understanding of these disorders. Here we show the utility of aCGH in detecting prognostic significant genomic alterations in multiple myeloma compared to standard chromosome and targeted FISH analysis. Multiple myeloma (MM) is a proliferation of malignant clonal plasma cells (PC) which accumulate in the bone marrow. It is a heterogeneous disease in which the genetic features of the malignant cells are the major contributing factor. Multiple myeloma is broadly divided into two biological genetic categories, hyperdiploid MM harboring multiple chromosome trisomies and a low frequency of IgH translocations and a non-hyperdiploid MM which have a high frequency of IgH translocations. There are also secondary genetic events that have been characterized in MM. Both the above genetic events in MM have major prognostic influence. The current clinical standard for identifying these genetic events in MM is conventional cytogenetics and targeted FISH analysis. However chromosome abnormalities are only detected in 30–40% of malignant PCs due to a low mitotic index in culture and FISH analysis only targets a few loci and therefore limiting in its use. In this study we compared the standard chromosome analysis of clinically and morphologically diagnosed MM to aCGH using a custom designed cancer genes targeted 44K Agilent array. It specifically interrogates 493 genes involved in carcinogenesis with evenly distributed probes mapped to each gene at an average spacing of 1 probe/10 kb, or at least 10 probes/gene for genes less than 100 kb in size [PMID: 20724749]. In this study a total of 53 patients with indication of MM, 9% cases (5/53) showed chromosome abnormalities by standard karyotype analysis as compared to 40% (21/53) of the cases that demonstrated a genomic change by aCGH. Furthermore only 3 of the cytogenetic abnormal cases were consistent with a MM profile of hyperdiplody, the other 2 cases had single chromosome events. While analysis of the genomic profile obtained from aCGH analysis clearly showed biological and prognostic stratification. A total of 69% (11/16) showed a hyperdiploid MM profile. In addition, 44% (7/16) cases had a gain of chromosome 1q which has been associated with a poor prognosis. All cases with the 1q gain had normal chromosome analysis. Recently a new mechanism of genomic instability termed chromothripsis has been described in 2–3 % of cancer genomes (PMID: 21215367). This is an acquired single catastrophic event during cancer development. This event has been described in multiple myeloma and has been associated to a poor outcome (PMID:21628407). We observed chromothripsis in 2 chromosomes in 2 cases. Based on this preliminary study it is quite compelling that aCGH provides a more accurate biological or prognostic profile in 69% of cases (11/16) vs 19% (3/21) by conventional cytogenetics. Therefore we conclude that the first line standard testing in Multiple myeloma should be aCGH and FISH for the IgH rearrangements and not conventional cytogenetics and FISH. Disclosures: No relevant conflicts of interest to declare.

The biliary excretion of cefoperazone and ceftazidime was studied by endoscopic cannulation of the common bile duct, in patients with complete biliary obstruction and in an unobstructed control group. Patients were given each drug prophylactically for 24 h before endoscopy and as a single dose at the time of cannulation. In unobstructed patients biliary excretion of ceftazidime was passive. At the time of cannulation bile contained 10% of the peak serum concentration, rising to 20% 90 min later. Cefoperazone excretion was active. At cannulation biliary concentrations were 200% of the serum peak, 900% at 60 min and 700% at 90 min. In obstructed patients, bile sampled immediately at decompression contained neither antibiotic. Passive excretion of both drugs occurred rapidly after relief of obstruction and biliary concentrations were 20% of maximum serum levels at 60 min. Twenty-four hours later passive excretion had further improved, but the active excretion mechanism of cefoperazone had still not recovered. We conclude that obstruction impairs active as well as passive biliary excretion of antibiotics, that drainage is essential for the control of sepsis in obstructed cholangitis, and that both cefoperazone and ceftazidime achieve similar and therapeutic concentrations in bile during the 24 h after decompression.

Tuberculostearic acid ([R]-10-methyloctadecanoic acid [TBSA] ) is a structural component of mycobacteria, and its detection in appropriate clinical specimens has potential application as a rapid screening method for the presence of Mycobacterium tuberculosis and other mycobacteria. We used the highly sensitive technique of gas chromatography-mass spectrometry (GC-MS) combined with selected ion monitoring (SIM) of m/e 312 and m/e 167 to detect TBSA in clinical specimens collected in Hong Kong, where tuberculosis is still common. The test was useful for the diagnosis of M. tuberculosis in sputum, pleural aspirates, bronchial washings, CSF and tissue biopsies. The test was highly specific and more sensitive than conventional microscopy, and more rapid but rather less sensitive than conventional culture methods.

Tuberculostearic acid, a structural component of Mycobacterium tuberculosis, was identified by gas chromatography/mass spectrometry with selected ion monitoring in cerebrospinal fluid (CSF) from 13 patients with proven and 8 out of 9 patients with suspected tuberculous meningitis; the negative result was in a patient whose symptoms and CSF abnormalities may have been due to systemic lupus erythematosus. Tuberculostearic acid was found in the CSF of only 1 patient out of 87 with non-tuberculous meningitis or non-infectious disorders; the single false-positive result was probably caused by intrathecal treatment with amikacin. Other aminoglycosides and antituberculous drugs did not interfere with the assay. In serial CSF samples from patients with tuberculous meningitis tuberculostearic acid was still present after 8 months of continuous supervised chemotherapy. Detection of tuberculostearic acid in CSF is a rapid, sensitive, and specific test for tuberculous meningitis, and can be used for retrospective diagnosis in patients who have been started on therapy.