Seroepidemiology of hepatitis C virus infection in Taiwan

The prevalence of antibody to hepatitis C virus among Chinese subjects in Taiwan was evaluated using a commercially available enzyme immunoassay. The overall prevalence of antibody to hepatitis C virus was 0.28% among 1,419 healthy subjects, 0.8% among 500 unselected paid blood donors and 0.4% among 793 pregnant women. The three offspring of the mothers positive for antibody to hepatitis C virus were all found to be positive for antibody to hepatitis C virus at birth but all became negative by the age of 6 mo. Among healthy subjects, none of 1,000 school children and young adolescents had antibody to hepatitis C virus. Among patients in selected "high-risk" groups, antibody to hepatitis C virus was detected in 100% of 9 hemophiliac patients who were positive for antibody to human immunodeficiency virus, in 53% of 115 intravenous drug abusers, in 34.4% of 96 hemodialysis patient and in 15.8% of 19 homosexual men who were positive for antibody to human immunodeficiency virus. Only 7.1% of 196 prostitutes, 5.9% of 34 spouses of patients positive for antibody to hepatitis C virus and 0.5% of 201 brothelgoers had antibody to hepatitis C virus. These findings suggest that hepatitis C virus is transmitted mainly by the parenteral route in Taiwan. Transmission from mother to infant is not an important mode of spread of hepatitis C virus.

Diphenhydramine toxicity in three children with varicella-zoster infection

Diphenhydramine hydrochloride is an antihistamine with anticholinergic properties that is frequently used both orally and topically for the temporary relief of pruritus. Significant systemic absorption may occur following topical administration of diphenhydramine in patients with varicella-zoster lesions. We describe three children with varicella-zoster infection (VZI) who developed bizarre behavior as well as visual and auditory hallucinations following topical applications of large amounts of diphenhydramine to the majority of skin surfaces. In two cases, oral diphenhydramine was also administered. Serum diphenhydramine concentrations approximated or exceeded those previously reported. In each case, a complete resolution of mental status abnormalities occurred within 24 hours after discontinuation of all diphenhydramine-containing products. Pharmacists and other health professionals should be aware of the potential toxicity of topical diphenhydramine in patients with VZI.

Pharmacokinetics of parenteral imipenem/cilastatin in patients on continuous ambulatory peritoneal dialysis

We investigated the pharmacokinetics of two intravenous (iv) dose regimens of imipenem/cilastatin in Chinese patients on chronic ambulatory peritoneal dialysis (CAPD), who had an average creatinine clearance of 3.2 ml/min/1.73 m2. Doses of 0.5 and 1.0 g produced mean peak serum imipenem concentrations of 30 and 70 mg/l respectively, about 60% of cilastatin. Peritoneal dialysis fluid (PDF) imipenem concentrations reached 20-30% of the serum peak 4-5 h after iv injection, and the lowest maximum PDF concentrations were 2 mg/l after the 0.5 g dose and 14 mg/l after 1.0 g. Thus both regimes produced PDF imipenem concentrations above the MICs of susceptible pathogens. The half-life of imipenem was 6.4 h and the plasma clearance 66 ml/min; serum and PDF imipenem were in equilibration after about 5 h. Cilastatin had a prolonged half-life of 19 h and a plasma clearance of 10 ml/min, and accumulated in both serum and PDF. With a 0.5 g dose, the pharmacokinetics of imipenem/cilastatin suggest that the combination may prove an effective treatment for peritonitis associated with CAPD.

Superinfection with hepatitis C virus in patients with symptomatic chronic hepatitis B

11/323 patients (3.4%) with symptomatic chronic hepatitis B were positive for antibody to hepatitis C virus (anti-HCV). The positive rate of anti-HCV in patients with serum alanine aminotransferase (ALT) levels greater than 200 U/l (n = 219) did not exceed that of the patients with ALT less than or equal to 200 U/l (n = 104) (2.7% vs. 4.8%). Of the 219 patients who were positive for hepatitis B e antigen (HBeAg) and/or hepatitis B virus-DNA (HBV-DNA), 5 (2.3%) had anti-HCV, while 6/104 patients (5.8%) who were positive for antibody to HBeAg (anti-HBe) had anti-HCV (p greater than 0.1). In contrast to the anti-HCV-negative patients, the patients with anti-HCV had a higher percentage of cirrhosis in their liver histological findings (36.4% vs 5.4%, p less than 0.005). In conclusion, the prevalence of HCV superinfection in symptomatic chronic hepatitis B patients is low and HCV superinfection is not an important factor in acute exacerbation of chronic hepatitis B. However, the superinfection with HCV may exacerbate the existing liver disease and accelerate its progression.

Effect of phosphatidylcholine on ultrafiltration in patients on continuous ambulatory peritoneal dialysis

Oral phosphatidylcholine at 900 mg/day was given to 4 patients with high lymph absorption for 8 weeks. Fluid and solute transfer before and after treatment were compared to 4 similar controls given placebo. None of the patients had overt ultrafiltration problems. After treatment, overnight peritoneal effluent phospholipid content did not change significantly. Ultrafiltration as well as solute and glucose transfer remained unchanged at the end of 8 weeks. A controlled trial on patients with overt ultrafiltration problems for a longer duration is required to further elucidate the role of phosphatidylcholine supplementation in patients on continuous ambulatory peritoneal dialysis.

Clinical and pathological features of tuberculous pleural effusion and its long-term consequences

A retrospective study of 83 cases of tuberculous pleural effusion showed that the mean age of the patients was 44 years and 10 patients (12%) were over the age of 70. Pleural fluid was smear positive for tubercle bacilli in none but culture positive in 23% of the cases. Pleural biopsy was a more sensitive method of diagnosis with granulomatous inflammation seen in 97% of cases. Five patients developed significant pleural thickening during chemotherapy requiring decortication. Twenty-two patients with tuberculous effusion diagnosed and treated over 2 years previously were traced for reassessment. None of them had significant pleural thickening and lung function tests did not show significant impairment compared to matched control subjects.

Primary biliary cirrhosis in Taiwan

Among 30 consecutive patients diagnosed with primary biliary cirrhosis (PBC) in Taiwan, 27 were females and the median age of symptom onset was 54.5 years. Most had similar clinical manifestations to those reported in the Western countries, but ascites and oesophageal varices as commonly found at the late stages of cirrhosis of liver were noted in nine patients (30%) and 13 patients (43%) respectively. Only one patient was asymptomatic. Hyperbilirubinaemia was noted in 21 patients (70%) and hypoalbuminaemia in 8 patients (27%). All patients had elevated serum alkaline phosphatase and alanine aminotransferase and 28 (93%) had antimitochondrial antibodies. Ten out of 21 patients (48%) were positive in antinuclear antibodies, of which most were of speckled type. Sixteen out of 18 patients (89%) had elevated serum IgM levels. Interestingly, only one of 26 patients (3.8%) was positive for hepatitis B surface antigen, in contrast to its high prevalence (15%) in the Taiwan population. Special associated diseases, including systemic lupus erythematosus, scleroderma, malignant lymphoma and hepatocellular carcinoma, were each noted in one patient respectively. Eight patients had a history of gallstones before the diagnosis of PBC. The mean follow-up period was 23.6 +/- 19.8 months, and nine patients died during that period. In conclusion, the clinical manifestations of PBC in Taiwan are similar to those in Western countries, but most of our cases were at later stages.

Heat probe thermocoagulation as a substitute for surgical intervention to arrest massive peptic ulcer hemorrhage: an experience in 153 cases

In a period of 2 years 7 months, we performed heat probe (HP) thermocoagulation in 153 cases of massive peptic ulcer hemorrhage. The male/female sex ratio was 125/28. The average age was 57.6 +/- 1.3 years (mean +/- SEM; range, 17 to 88). There were 69 cases (45.1%) of spurting hemorrhage, 50 cases (32.7%) of oozing hemorrhage, and 34 cases (22.2%) of nonbleeding visible vessels. Seventy-seven patients (50.3%) were in shock before therapy. After therapy we obtained initial success in 147 cases (96.1%). Rebleeding episodes occurred in 23 patients (15.6%) within 1 month after therapy. Nineteen patients received a second therapy, and treatment in 15 of these cases (78.9%) was ultimately successful. Finally, treatment in 142 cases (92.8%) was ultimately successful. The duration of hospitalization was 6.3 +/- 0.4 days (mean +/- SEM). After discharge all patients were followed at the outpatient department for at least 1 month. Sixty-seven patients were followed endoscopically for at least 2 to 3 months after therapy. Fifty-six patients (83.6%) had a healed scar at the previous bleeding site 2 months after therapy, and 62 patients (92.5%) had a healed scar 3 months after therapy. We conclude that HP thermocoagulation is an ideal and reliable modality of therapeutic endoscopy in arrest of massive peptic ulcer hemorrhage. HP thermocoagulation may become the first choice of therapy for massive peptic ulcer bleeding in the near future.

Isoniazid-rifampin-induced hepatitis in hepatitis B carriers

From January 1984-December 1987, 1783 patients received combination therapy of isoniazid, rifampin, and ethambutol for the control of tuberculosis. Forty-two developed symptomatic hepatitis during the period of treatment. Fifteen were hepatitis B virus carriers, and the remaining 27 were noncarriers. The peak serum transaminase and bilirubin levels were higher in carriers. Seven carriers died of fulminant or subacute hepatic failure, and only 1 noncarrier died. Eleven carriers had detectable serum hepatitis B virus deoxyribonucleic acid during the acute stage of hepatitis. The roles of isoniazid-rifampin combination therapy and hepatitis B virus in the adverse outcomes of carriers were discussed.

Rapid diagnosis of bacterial meningitis by the detection of a fatty acid marker in CSF with gas chromatography-mass spectrometry and selected ion monitoring

A chemical marker of bacterial meningitis was sought by comparing derivatives of sterile cerebrospinal fluid (CSF) with cultures of organisms in spinal fluid and artificial media. The technique of gas chromatography-mass spectrometry with selected ion monitoring (GC-MS-SIM) was used, optimised for the analysis of fatty acids. Twenty candidate ions were screened, and an ion of mass: charge ratio (m/e) 268 was chosen for detection in clinical specimens. The origin of this marker is unknown, but it is probably the molecular ion of a C16:1 fatty acid. In 135 clinical specimens of CSF examined, the m/e 268 ion was found to be a useful marker for the common organisms that cause bacterial meningitis, giving a sensitivity of 88% and a specificity of 98%. The method was more rapid and more sensitive than conventional microscopy and culture, but CSF containing coagulase-negative staphylococci, Mycobacterium tuberculosis, Cryptococcus neoformans and some other uncommon pathogens gave inconsistent results. Many organisms produced characteristic ion profiles with multiple-ion monitoring, and this method of chemical analysis holds promise for the rapid diagnosis of bacterial infections to genus or species level.

A tuberculostearic acid assay in the diagnosis of sputum smear-negative pulmonary tuberculosis. A prospective study of bronchoscopic aspirate and lavage specimens

OBJECTIVE

To determine whether the detection of tuberculostearic acid (TBSA) in bronchial aspirate and bronchoalveolar lavage specimens is useful for the rapid diagnosis of active pulmonary tuberculosis in patients suspected of having the disease.

SETTING

A pulmonary clinic in a teaching hospital.

PATIENTS

Forty patients suspected of active pulmonary tuberculosis but who failed to produce sputum or whose sputum smears were negative for acid-fast bacilli on at least 3 occasions, 29 of whom were subsequently confirmed to have tuberculosis. A group of 13 patients who were having fiberoptic bronchoscopy for other reasons served as controls.

INTERVENTION

All patients had fiberoptic bronchoscopy; bronchial aspirate, bronchoalveolar lavage, and sputum specimens were obtained when possible.

MEASUREMENTS AND MAIN RESULTS

All specimens were examined microscopically for acid-fast bacilli, cultured for mycobacteria, and assayed for TBSA by gas chromatography and mass spectrometry with selected ion monitoring. Only 4 of the 29 patients with tuberculosis were diagnosed by direct microscopy compared with 26 by TBSA assay. In 2 patients who required surgical biopsy for conventional diagnosis, the TBSA test was positive. There were no false-positive TBSA results in the 13 controls, but 2 of 5 sputum specimens from the 11 test patients in whom tuberculosis was excluded were falsely positive, probably because of contamination with mouth flora. Because sputum can rarely be obtained from these patients and may give false-positive results, it is not a good specimen for TBSA assay. Sensitivities and specificities of the test for the other specimens were as follows: aspirate, 0.52 (CI, 0.32 to 0.71) and 1.00 (CI, 0.75 to 1.00); lavage, 0.68 (CI, 0.46 to 0.85) and 1.00 (CI, 0.84 to 1.00); aspirate and lavage combined, 0.79 (CI, 0.60 to 0.92) and 1.00 (CI, 0.86 to 1.00).

CONCLUSIONS

The TBSA assay for bronchial aspirate and bronchoalveolar lavage fluid is useful for rapidly diagnosing "smear-negative" pulmonary tuberculosis. In these specimens it is highly specific and more sensitive than microscopy. This assay could be used to diagnose other mycobacterial infections, however, it cannot distinguish among species.

Climatic factors and peritonitis in CAPD patients

From March 1983 to December 1987 the relation of the occurrence of all episodes of peritonitis in CAPD patients to climatic factors, such as temperature and relative humidity was examined. Altogether 389 episodes were recorded in 239 patients. Peritonitis due to Staphylococcus epidermidis, Gram-negative organisms and culture-negative episodes was most frequent during the hot months of the year, June to October. The occurrence of peritonitis due to Staphylococcus aureus was uniformly distributed throughout the year. Relative humidity did not seem to affect the frequency of peritonitis.

Rapid HPLC assay of fluoroquinolones in clinical specimens

A simple isocratic HPLC procedure was developed for the analysis of seven quinolones and their metabolites in clinical specimens. It is likely that this system can be used for the assay of many other quinolone compounds, but not for nalidixic acid and the ciprofloxacin metabolite sulpho-ciprofloxacin which appear to be adsorbed in the column. Sample preparation takes approximately 20 min, and HPLC analysis is completed within 15 min with a simple solvent system eluted on a reversed phase column. The procedure is rapid, sensitive and specific, and is a modification of an assay for chloramphenicol and beta-lactam antibiotics. This method is therefore particularly useful for clinical laboratories, since a single HPLC system can be used for assays of chloramphenicol, beta-lactams and quinolones.

Excitatory synaptic responses in turtle cerebellar Purkinje cells

1. Climbing fibre responses (CFRs) and parallel fibre responses (PFRs) in Purkinje cells have been analysed in intracellular recordings obtained at various levels from cell body to terminal dendrites in the turtle cerebellum in vitro. 2. With increasing stimulus intensity, the PFR recorded in distal dendrites displayed an early regenerative component which was graded at rest and at hyperpolarized membrane potentials, but was all-or-none at depolarized membrane potentials. 3. The all-or-none component had the same characteristics as Ca2+ spikes triggered by passing depolarizing current through the recording electrode. 4. The repolarizing phase of the PFR had a fast component enhanced by depolarization and diminished by hyperpolarization. 5. In the mid-molecular layer the PFR also included a plateau component which was increasingly prolonged by depolarization and abolished by hyperpolarization. 6. CFRs recorded in the soma had a plateau component, prolonged by local depolarization and abolished by local hyperpolarization. 7. The CFR in distal dendrites included a regenerative component. In some cells this component appeared in an all-or-none manner with local depolarization. In other cells it was smoothly graded with local polarization. 8. In mid-molecular records the CFR was prolonged by local depolarization and presumably electrotonically affected by the configuration of the response more distally and proximally in the cell. 9. It is concluded that excitatory synaptic responses in Purkinje cells include a regenerative Ca2+-mediated spike component in the spiny dendrites and a plateau component located in the proximal dendrites and/or the cell body. It is shown that both responses are modulated in configuration by the local membrane potential. In the spiny dendrites activation and inactivation of the transient hyperpolarizing potential appear to govern the Ca2+ influx during the CFR.

Diagnosis of nasopharyngeal tuberculosis by detection of tuberculostearic acid in formalin fixed, paraffin wax embedded tissue biopsy specimens

The use of gas chromatography and mass spectrometry with selected ion monitoring detected tuberculostearic acid (TBSA) in 10 of 12 formalin fixed, paraffin wax embedded nasopharyngeal and head and neck biopsy specimens from patients with confirmed tuberculosis and carcinoma, and in one of 50 control specimens (giving a sensitivity of 83% and a specificity of 98%). The two false negative cases had very small tissue fragments and the patient with a false positive result may have had pulmonary tuberculosis. Tuberculostearic acid (TBSA) was also detected in nine of 16 specimens from the head and neck region with non-caseating granulomas suspected, but not confirmed, to be tuberculosis. It is concluded that nasopharyngeal tuberculosis is relatively common in Hong Kong and should be considered when biopsy specimens show granulomas. The detection of TBSA in tissue biopsy specimens is a useful, rapid method for the diagnosis of tuberculosis and other mycobacterial infections, and can be conveniently performed within two days on formalin fixed and paraffin wax embedded material.

Stimulus-induced extracellular pH transients in the in vitro turtle cerebellum

In a number of CNS preparations, neuronal activation has been shown to result in a rapid extracellular alkaline transient, followed by a prolonged acid shift. The isolated turtle cerebellum was used to investigate the early alkaline transient. Double-barreled ion-sensitive microelectrodes for H+, K+ and tetramethylammonium were used to measure field potentials and extracellular ion and volume shifts in response to bipolar electrical stimulation of the parallel fibers. Transition from 15 mM HEPES to 35 mM HCO3- -buffered Ringer decreased the amplitude of the alkaline shift, presumably due to a marked increase in extracellular buffering power. In HEPES-buffered Ringer, repetitive stimulation produced alkaline shifts as large as 0.3-0.4 pH. Single shocks produced an alkaline shift of 0.006 +/- 0.0002 pH with a latency as short as 70 ms. Kynurenic acid (an excitatory amino acid antagonist), or Mn2+, blocked the alkaline shift and the postsynaptic component of the field potential. The alkaline shift was not blocked by the Na-H exchange inhibitor amiloride. The relationship between pHo and extracellular volume transients was studied using tetramethylammonium as an extracellular volume indicator. In nominally HCO3-free Ringer, stimulation at 5 Hz for 10 s caused a decrease in extracellular volume of 3.0 +/- 0.2 per cent. The volume transient was unaffected by 3 mM Mn2+, while the alkaline shift was completely abolished. The data for the alkaline shift are consistent with a channel-mediated transmembrane flux of proton equivalents. The size of the pH change and the underlying perturbation it represents, indicate that acid-base shifts may be a functionally important consequence of neuronal activity.

Long-term immunogenicity and efficacy of hepatitis B vaccine in infants born to HBeAg-positive HBsAg-carrier mothers

In an attempt to evaluate the long-term immunogenicity and efficacy of plasma-derived hepatitis B vaccine in preventing hepatitis B virus infection, 199 infants born to hepatitis B e antigen-positive hepatitis B surface antigen-carrier mothers were found to be antibody to HBsAg-positive (greater than or equal to 10 mIU per ml) 2 months after the first booster of hepatitis B vaccination at age 1, and their serum HBsAg and anti-HBs were rechecked annually to ages 3 to 5. Of the nine infants whose initial anti-HBs were low (10 to 100 mIU per ml) in concentration, four (44%) were found to be anti-HBs seronegative at age 3, while none of the 127 vaccine responders with high anti-HBs levels (greater than 1,000 mIU per ml) lost their anti-HBs during the 4-year follow-up period. Also, in 63 infants whose initial anti-HBs titers were around 101 to 1,000 mIU per ml, only two lost their anti-HBs at age 4, and another two at age 5, respectively. Whether the vaccine responders lost their anti-HBs or not, no hepatitis B virus infection occurred in these vaccinees during the follow-up period. Thus, in the first 5 years of life, the protective efficacy in the high-risk infants who responded to plasma-derived hepatitis B vaccine was 100%. Because of the diversity of anti-HBs response in individuals, we suggest testing anti-HBs titer in all vaccinated infants after the first booster vaccination in order to calculate the time of next booster before the minimal protective level is reached.

Effects of electric fields on transmembrane potential and excitability of turtle cerebellar Purkinje cells in vitro

1. Transmembrane potential (TMP) responses of Purkinje cells (PCs) in isolated turtle cerebellum to externally applied quasi-steady-state electric fields aligned with the dendritic axis were continuously measured using simultaneous intracellular and extracellular recording. TMP was obtained by subtraction of extracellular voltage fields from intracellular potential recorded at the same depth in the cerebellum. 2. The applied field changed the TMP with the polarity and amplitude dependent on the location on the PC membrane. This response at a given location increased linearly with external field up to a threshold level, beyond which active responses appeared. 3. The basic effect on TMP consisted of depolarization in the half of the dendrite towards which the fields were directed, and hyperpolarization in the other half. A pooled TMP depth-profile shows a steady increase in polarization from the middle of the molecular layer towards each end. This profile correlates with that predicted from previously proposed cable models, giving them empirical support for the first time. 4. Active responses were triggered by the field-induced depolarization. Tetrodotoxin (TTX)-sensitive action potentials arose with the primary depolarization in the somatic region. Notched, Ca2+-dependent action potentials arose with primary depolarization in the distal and mid-dendritic regions. 5. A TTX-sensitive voltage plateau was triggered by TMP-depolarization in the proximal region. It in turn activated Na+-spike trains. The frequency of spiking was proportional to the external field. At around 160 spikes/s, the Na+ spikes inactivated, and the TMP level rose to a more depolarized plateau. This latter plateau was also TTX-sensitive. 6. During depolarization of the distal dendritic region, sometimes a Ca2+-dependent plateau was observed. It appears to be associated with a small conductance increase. 7. Field-induced hyperpolarization suppressed local spiking and voltage plateaux, but remote Ca2+ spikes with reduced amplitude appeared in recordings from the proximal region. Similarly, in the distal region, low-amplitude, remote Na+ spikes and a Na+ plateau were observed superimposed on the hyperpolarizing baseline. The Na+ plateau apparently did not contribute to shunting of membrane currents in the distal dendrite. 8. The phase characteristics of the action potentials correlate with the modulation pattern noted in our extracellular study (Chan & Nicholson, 1986). Thus, the extracellular units ("giant spikes") were probably Na+ spikes activated in the soma and spread distally. Occasionally Ca2+ spikes, with a higher threshold, might also be activated to give dual-phase response.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of enzyme- and radio-immunoassay kits to detect hepatitis B surface antibody response among hepatitis B vaccinees

A total of 288 of sera was obtained from 96 hepatitis B vaccinees to test antibody to hepatitis B surface antigen (anti-HBs) by enzyme immunoassay (EIA) and radioimmunoassay (RIA), respectively. An anti-HBs titer greater than 10 mIU/mL is required for immunity; 172 (59.7%) were positive by EIA and 173 (60.1%) were positive by RIA. A correlation study of anti-HBs titers tested by these two methods showed a correlation coefficient r = 0.889 (n = 162, p less than 0.001). Of 173 serum specimens whose anti-HBs were positive by RIA, 10 were negative by EIA; those 10 had had anti-HBs titers between 11 to 20 mIU/mL by RIA. Among 172 serum specimens whose anti-HBs were positive by EIA, 9 were negative by RIA; 3 of those were between 21 to 70 mIU/mL, and 6 were between 11 to 20 mIU/mL by EIA. Of the 96 vaccinees, following first dose of hepatitis B vaccination their anti-HBs response rates were found to be 20.8% by EIA and 17.7% by RIA. Following second and third vaccinations, their anti-HBs response rates were 65.6% and 92.7% by EIA, and 71.9% and 90.6% by RIA, respectively. Thus, EIA correlates well with RIA for anti-HBs testing especially when its titers are greater than 70 mIU/ml.

Symptomatic anti-HBe positive chronic hepatitis B in Taiwan with special reference to persistent HBV replication and HDV superinfection

Ninety-four patients, who were admitted with symptoms of liver disease and found to be positive for hepatitis B surface antigen and antibody to hepatitis B e antigen (anti-HBe), were examined for hepatitis B virus (HBV) DNA in serum and immunoglobulin antibody to hepatitis B core antigen and liver biopsies were stained for hepatic hepatitis B core antigen. Of 94 patients, 34 (36%) had evidence of HBV replication and 35 (37%) evidence of hepatitis D virus (HDV) superinfection. Most of the latter two groups of patients (greater than 70%) had evidence of chronic active hepatitis or active cirrhosis in their liver biopsies. The majority of these patients (greater than 80%) also had high levels of serum alanine aminotransferase (greater than 200 U/L) during the acute stage of their illness, and suffered from prolonged hepatic inflammation (greater than 1 year). Many of the patients (59%) also experienced frequent (1-6 episodes) relapsing exacerbations during a two-year follow-up period. Thus, persistent replication or reactivation of HBV and HDV superinfection were the two major causes of clinical exacerbations in anti-HBe-positive chronic HBV carriers in Taiwan, and also played an important role in the progression of their liver diseases and unfavorable outcomes.

Diagnosis of pulmonary tuberculosis by detection of tuberculostearic acid in sputum by using gas chromatography-mass spectrometry with selected ion monitoring

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 for detecting TBSA in 405 clinical sputum specimens collected in Hong Kong, where tuberculosis is still common. TBSA was detected in 39 M. tuberculosis smear-positive, culture-positive specimens; 63 of 66 smear-negative, culture-positive specimens; and 1 of 300 smear-negative, culture-negative specimens. Thus, for screening of sputa from individuals with suspected pulmonary tuberculosis, the detection of TBSA by GC-MS/SIM is highly specific and more sensitive than conventional microscopy and more rapid but slightly less sensitive than conventional culture methods.