Heterogeneity in antifungal susceptibility of clones of Candida albicans isolated on single and sequential visits from a HIV-infected southern Chinese cohort

The increased frequency and severity of candidal infections in human immunodeficiency virus (HIV)-infected individuals has prompted the wide use of antifungals, such as amphotericin B, ketoconazole, and fluconazole, resulting in the emergence of drug-resistant strains of Candida albicans. To study this phenomenon in an ethnic Chinese cohort, we isolated multiple colonies of Candida from the oral cavities of 16 HIV-infected patients on single and subsequent sequential visits over a period of 12 months. Ten of the 16 patients had sporadic episodes of oropharyngeal candidiasis (Group A), while the remainder were asymptomatic with respect to this condition (Group B). Oral rinses were collected and immediately processed in the laboratory for the isolation of C. albicans in a standard manner. A total of 433 C. albicans isolates were tested for their susceptibility to amphotericin B, ketoconazole and fluconazole by an agar diffusion method using the commercially available E-test. All tested isolates demonstrated variable susceptibility to amphotericin B, ketoconazole and fluconazole. The minimum inhibitory concentration (MIC) of the isolates for amphotericin B, ketoconazole and fluconazole ranged from <0.002-1.5 microg/ml, <0.002-4.0 microg/ml and <0.016-32 microg/ml, respectively. Sequential isolates of a few patients demonstrated variable susceptibility to all the antifungals, and no discernible MIC pattern emerged either in group A or B over time. Interestingly, significant variation in antifungal susceptibility was also noted in isolates obtained from the same patient on a single visit. Sequential yeast isolates in 9 of 16 patients (56%) demonstrated significant differences in MIC within and between visits for both amphotericin B and ketoconazole, while a lower percentage--44%(7/16)--exhibited this trait for fluconazole. Our study demonstrates the diversity in antifungal susceptibility in either commensal or "infective" oral strains of C. albicans in HIV disease, and shows the need for vigilance for the emergence of resistant strains, and for frequent antifungal susceptibility studies.

Absolute quantification of regional myocardial uptake of 99mTc-sestamibi with SPECT: experimental validation in a porcine model

We have evaluated a method for absolute in vivo quantification of 99mTc-sestamibi uptake in a porcine model of myocardial perfusion.

METHODS

Correlated CT and radionuclide images were obtained from eight adult pigs using a combined CT-SPECT imaging system. In each case, the CT image is used to generate an object-specific attenuation map that is incorporated into an iterative algorithm for reconstruction and attenuation correction of the radionuclide image. Anatomic information available from the correlated CT image is used to correct the radionuclide image for partial-volume errors by mathematically modeling the radionuclide imaging process. A volume of interest, or template, that approximates the geometric extent of the myocardium is defined from the CT image. Once defined, the template is assigned unit activity and is mathematically projected using a realistic physical model of the radionuclide imaging process including nonideal collimation and object-specific attenuation. The template is then reconstructed from these projections to obtain a pixel-by-pixel partial-volume correction for the myocardium in the radionuclide image. The CT image is also used to delimit the anatomic boundaries of the myocardium for quantification of the radionuclide images. The pixel intensities in the corrected radionuclide image are calibrated in units of activity concentration (MBq/g) and compared with the ex vivo activity concentration measured directly from the excised myocardium.

RESULTS

Without corrections, the measured in vivo activity concentration in the porcine myocardium was only 10% of the true value. Correcting for object-specific attenuation improved the accuracy of this measurement but resulted in values that were still only 42% of the true value. By correcting for both attenuation and partial-volume errors, we were able to achieve absolute quantification with an accuracy error near 10%.

CONCLUSION

We have shown that, by applying object-specific attenuation corrections and suitable partial-volume corrections, absolute regional activity concentration can be measured accurately in the porcine myocardium.

Mandible fractures: a 3-year retrospective study of cases seen in an oral surgical unit in Singapore

A retrospective study of patients referred to the Department of Oral and Maxillofacial Surgery at Singapore General Hospital/National Dental Centre with mandibular fractures over a 3-year period from June 1995 to May 1998 was carried out. The cause, age, sex, race and anatomical distribution of the fractures were analysed for each of the 123 patients. The main cause of trauma was road traffic accidents (RTAs) (35.8%), of which 79.5% were motorcyclists. The highest incidence of trauma was in the 20-29 year age group (46.3%). Males outnumbered females in a ratio of 7.8:1. The parasymphysis was the most common site of injury (30.9%), and combined condylar and parasymphyseal fractures (26.0%) was the most common combination seen.

Surgical treatment of recalcitrant radiation-induced gastric erosions

BACKGROUND

Uncontrolled bleeding as a result of radiation gastritis in patients who have pharyngo-laryngo-esophagectomy and gastric pull-up is seldom reported. Surgical resection in the management of this condition has rarely been described.

METHOD

A 66-year-old man with hypopharyngeal cancer was treated by pharyngo-laryngo-esophagectomy and gastric transposition. He received postoperative radiotherapy and had recurrent hemorrhagic gastritis, necessitating surgical resection. The manubrium was resected to access the mediastinal part of the gastric conduit. The diseased part of the gastric conduit was removed and a free jejunal graft was interposed to replace the resected stomach.

RESULTS

Manubrial resection offered adequate access to the stomach transposed in the mediastinum, and the life-threatening bleeding gastritis was successfully controlled by surgical resection.

CONCLUSION

Surgical resection of the radiation-damaged transposed stomach through a manubrial resection approach can safely be performed. Free jejunal graft is the choice of reconstruction of the circumferential defect.

Rat ovarian interleukin-1alpha: interleukin-1-dependent in vitro expression

Evidence exists supporting the possibility that intraovarian interleukin-1 (IL-1) may play an intermediary role in the periovulatory cascade. Although the existence of a mammalian intraovarian IL-1 system has been convincingly demonstrated, most efforts have focused on the possibility that the mammalian ovary is a site of IL-1b production, reception, and action. The objective of this study was to explore the possibility of ovarian IL-1a expression, characterize its pattern of expression by cultured ovarian cells, and study its hormonal regulation. The basal in vitro expression of IL-1a by cultured whole ovarian dispersates from immature rats increased spontaneously, reaching a peak (sixfold increase over untreated controls) at 4 h. Treatment with an IL-1 receptor antagonist (IL-1RA), human chorionic gonadorropin, or IL-1b failed to attenuate the initial 4-h burst of IL-1a expression. By contrast, treatment of whole ovarian dispersates with IL-1b for 48 h resulted in significant upregulation of IL-1a transcripts (60-fold increase). This IL-1b effect was completely blocked by cotreatment with IL-1RA, thereby suggesting mediation via a specific IL-1 receptor. The IL-1b effect proved to be protein biosynthesis and eicosanoid dependent, nitric oxide independent, and relatively specific in that it was not reproduced by a select series of other granulosa cell agonists.

The identification of credit card encoders by hierarchical cluster analysis of the jitters of magnetic stripes

The relative bit density variation graphs of 207 specimen credit cards processed by 12 encoding machines were examined first visually, and then classified by means of hierarchical cluster analysis. Twenty-nine credit cards being treated as 'questioned' samples were tested by way of cluster analysis against 'controls' derived from known encoders. It was found that hierarchical cluster analysis provided a high accuracy of identification with all 29 'questioned' samples classified correctly. On the other hand, although visual comparison of jitter graphs was less discriminating, it was nevertheless capable of giving a reasonably accurate result.

Low yield of chest radiography in screening for active pulmonary tuberculosis in HIV-infected patients in Hong Kong

This study assessed the usefulness of routine chest radiography for detecting active pulmonary tuberculosis in persons infected with human immunodeficiency virus (HIV) without suggestive symptoms in Hong Kong. Tuberculosis is common in this locality and tuberculosis/HIV co-infection has been a frequent and significant problem. Records of patients attending the largest HIV clinic were reviewed. Three hundred and eleven routine chest radiographs were performed among 191 HIV-infected patients with a total follow-up period of 792 person years. Of the 22 routine chest radiographs that had abnormalities in the lungs or hilar region, only one had led to the diagnosis of pulmonary tuberculosis. No patient with a normal chest radiograph was diagnosed to have tuberculosis within the following 2 months. The low yield (0.32%) suggests that routine chest radiography is not useful in screening for active pulmonary tuberculosis in asymptomatic HIV-infected patients even in a locality where the tuberculosis rate is high.

Low yield of chest radiography in screening for active pulmonary tuberculosis in HIV-infected patients in Hong Kong

This study assessed the usefulness of routine chest radiography for detecting active pulmonary tuberculosis in persons infected with human immunodeficiency virus (HIV) without suggestive symptoms in Hong Kong. Tuberculosis is common in this locality and tuberculosis/HIV co-infection has been a frequent and significant problem. Records of patients attending the largest HIV clinic were reviewed. Three hundred and eleven routine chest radiographs were performed among 191 HIV-infected patients with a total follow-up period of 792 person years. Of the 22 routine chest radiographs that had abnormalities in the lungs or hilar region, only one had led to the diagnosis of pulmonary tuberculosis. No patient with a normal chest radiograph was diagnosed to have tuberculosis within the following 2 months. The low yield (0.32%) suggests that routine chest radiography is not useful in screening for active pulmonary tuberculosis in asymptomatic HIV-infected patients even in a locality where the tuberculosis rate is high.

Indinavir-associated facial lipodystrophy in HIV-infected patients

The objectives of this study were to document the prevalence of facial lipodystrophy in patients with HIV infection receiving protease inhibitors and to identify associated factors. All patients with HIV infection receiving protease inhibitors seen at an HIV clinic in Hong Kong during a 2-month period, from August to October 1997, were assessed for facial lipodystrophy. Among 29 patients who had been receiving indinavir for 3 months or more, facial lipodystrophy was found in 7 (24%). Facial lipodystrophy in these patients was found to be an isolated event and was not associated with noticeable wasting elsewhere. The development of facial lipodystrophy was not found to be associated with age, sex, ethnicity, route of HIV transmission, CD4 cell count, history of AIDS-defining illness, or concurrent anti-retroviral treatment. Facial lipodystrophy was not observed in patients who had received indinavir for less than 3 months. The condition was also not found in patients taking other protease inhibitors, although this could be due to the small sample size. Prospective study of this condition with a larger sample and with objective anthropomorphic measurements would be desirable. In conclusion, facial lipodystrophy is a common occurrence among patients receiving indinavir, and physicians should be alerted to this condition.

Chronic cough in patients with HIV infection

We retrospectively studied the clinical spectrum, course and outcome of 26 patients with HIV infection and chronic cough. All except 2 were homo-/bisexual males. 22 (85%) had AIDS. They had cough for a mean of 75 d with sputum production (88%) and dyspnoea (77%) being the commonest associated symptoms. Sputum examination and chest X-ray were useful initial investigations. CT scan of the chest and sinuses had a high rate of abnormal results for selected patients (89-100%). Cause of cough was found in 21 patients (81%): bronchopulmonary infections (17), Kaposi's sarcoma (5) and sinus infections (3). Patients with sinopulmonary infections tended to have longer duration of cough. Overall, 4 patients (15%) had significant improvement in the illness with cough during the study period. Four patients with bronchopulmonary infections died. We concluded that chronic cough is a heterogeneous clinical problem in advanced HIV-infected patients, most commonly caused by an infective process. Extrapulmonary disease, such as sinusitis, has to be considered and investigated. The clinical course and outcome is unfavourable for most of the patients.

Proposed CD4(+) T-cell criteria for staging human immunodeficiency virus-infected Chinese adults

The present treatment, prophylaxis, and prognostic staging of human immunodeficiency virus (HIV) disease rely heavily on peripheral CD4(+) T lymphocyte (CD4) changes. We correlated the clinical course of events and CD4 changes among consecutive HIV-infected ethnic Chinese adults in Hong Kong. Using death as end point, the estimated proportion survival and death incidences were used to compare CDC and proposed staging criteria based on stratified baseline CD4. A separate set of baseline CD4 per microliter (/microl) (percentage lymphocytes) stratification criteria of 1, >220/microl (>12%); 2, 100-220/microl (6-12%); and 3, <100/microl, (<6%) is proposed which can be used for staging HIV-infected Chinese adults. For our study population, our proposed criteria for stratifying baseline CD4 gave better discrimination and more predictive power than the CDC criteria. We assessed the potential impact of these new proposed criteria on anti-retroviral treatment and prophylaxis against opportunistic infections in our adult HIV-infected population.

Comparing the first and second hundred AIDS cases in Hong Kong

OBJECTIVES

To study the clinical and epidemiological features of the first 200 AIDS patients in Hong Kong.

METHOD

A retrospective analysis of the data reported to the Department of Health. The patients were divided into two groups of first 100 and second 100 cases for comparison so as to discern the temporal changes.

RESULTS

The first 100 AIDS cases were reported from February 1985 through to March 1994 (122 months) while the second 100 in the following 26 months. For both groups, they were predominantly male (94%, 89%), Chinese (66%, 74%) who acquired HIV via sex (83%, 91%). The proportion of Caucasians and homo/bi-sexual contacts in first and second 100 cases have fallen from 26% to 12% (p = 0.012), and from 53% to 31% (p = 0.006) respectively. For primary AIDS-defining illness (ADI), the frequency of Pneumocystis carinii pneumonia (PCP) has decreased (46% to 30%, p = 0.03) while that of tuberculosis (10%, 19%) and Penicillium marneffei (5%, 14%) infection have increased. Mycobacterium avium intracellualare and cytomegalovirus infection have become commoner subsequent ADIs. Frequency of PCP (22%, 9.5%) as the cause of death have dropped while that of tuberculosis has risen (4.8%, 14.3%). Median survival probability had improved from 7.3 months for the first half of patients to 11.9 months for the second half.

CONCLUSION

Incidence of PCP has declined among local AIDS patients whereas tuberculosis, penicilliosis, MAI, and CMV diseases have increased. Survival chance of AIDS patients has improved over the years.

Measurement of anti-dsDNA: a comparative study of two ELISA and the Crithidia assay

We compared the measurement of anti-dsDNA by a commercial ELISA test (DIASTAT), an in-house ELISA and the Crithidia luciliae assay in cross-sectional sera samples of 209 systemic lupus erythematosus (SLE) patients and 64 patients with a variety of rheumatological, autoimmune and non-autoimmune diseases in Hong Kong. The Crithidia assay was found to be the least sensitive (17%) but most specific (95%) method for detection of a positive result in SLE patients. The DIASTAT assay has a higher sensitivity (68%) but lower specificity (80%) than the in-house ELISA test (32% sensitivity and 89% specificity). The positive predictive value of the three assays are comparable at 90-92% while DIASTAT had the highest negative predictive value (44%). There was good linear correlation (r = 0.7) between the two ELISAs. ELISA can serve as a useful screening test for anti-dsDNA in SLE patients and doubtful cases can then be confirmed by another method such as radio-immunoassay.

Scytalidium dimidiatum and Lecythophora hoffmannii: unusual causes of fungal infections in a patient with AIDS

Immunocompromised patients are susceptible to infections by fungi that seldom cause disease in humans. We describe a human immunodeficiency virus-infected patient who had simultaneous infections with two fungi which are rare causes of serious infection: Lecythophora hoffmannii, causing chronic sinusitis, and Scytalidium dimidiatum, causing skin lesions, lymphangitis, and lymphadenitis. The clinical and pathologic findings are discussed.

An economical piezoelectric phase modulator for fiber optic sensors

A homemade piezoelectric phase modulator for interfero-metric fiber optic sensors was fabricated using piezoelectric buzzers as strain elements. Six piezoelectric elements were embedded between the two halves of a bakelite cylinder split along its axis and secured tightly together again to form a cylinder. Single-mode optical fiber was then wound around the cylinder to complete the unit. Up to a frequency of 500 Hz, the phase shift produced by the modulator is linearly proportional to the amplitude of the applied voltage. The sensitivity of the phase modulator is about 3.6 rad/V and has a dynamic range of 1,000 rad, which is sufficient for most phase modulation purposes.

Haemophilia and HIV infection in Hong Kong

This is a retrospective study of the problems faced and support received by HIV (human immunodeficiency virus) infected haemophilia patients in Hong Kong. Between December 1984 and December 1994, 63 patients were detected to be HIV positive, out of a total of 231 haemophiliacs screened. Infection could be traced back to before August 1985, when safer heat-treated clotting factors were not yet available. Psychosocial impacts were obvious in this group of patients because of the double blow of HIV infection and haemophilia. Amongst the more evident problems were obstacles in schooling, employment difficulties, and disturbed relationships with family and friends, to mention a few. Psychosocial support services have been rendered by both the government and non-governmental organizations in Hong Kong. Financial assistance has also been given by the government since April 1993. To date, only eleven (17.5%) patients were known to have progressed to AIDS. Medical treatment, psychosocial support and financial assistance are integral components of an effective AIDS care programme for HIV-infected haemophilia patients.

Inactivated hepatitis A vaccine in healthy Chinese adults

OBJECTIVES

To study the safety, tolerability of and immune response to an inactivated hepatitis A vaccine in healthy Chinese adults.

DESIGN

Seronegative subjects were randomized to receive formalin-inactivated, alum-adjuvanted hepatitis A vaccine (25 units, MSD) at 0, 24 weeks (group I) or 0, 2, 24 weeks (group II).

SUBJECTS

Healthy Chinese adults aged 18 years or above were recruited. All subjects were staff of a regional hospital and primary care clinic in Hong Kong.

MAIN OUTCOME MEASURES

Side-effects, tolerance, seroconversion rate and geometric mean titre (GMT) of the two groups were noted and compared.

RESULTS

Thirty-two and 28 people were recruited into group I and group II, respectively. Antibody against hepatitis A developed in 100% of the recipients 1 month after the last dose of either regimen, with a GMT of around 450 IU L-1. High antibody levels were maintained at the end of one year. There was no statistically significant difference in the seroconversion rates and GMTs between the two regimens of vaccination. All subjects in group I seroconverted at 24 weeks after one single dose of the vaccine. No adverse effects were reported except for complaints of some mild local and constitutional symptoms.

CONCLUSIONS

The inactivated hepatitis A vaccine is highly immunogenic, safe and well-tolerated.

The first one hundred AIDS cases in Hong Kong

OBJECTIVE

To study the clinical and epidemiological characteristics of the first 100 reported AIDS cases in Hong Kong.

PATIENTS AND METHODS

The case records of the first 100 AIDS cases reported to the Department of Health were retrieved. An analysis was made on their demographic data, clinical and immunologic profile, treatment received as well as mortality.

RESULTS

The AIDS patients were reported over a ten-year period, from February 1985 to March 1994. The majority of them were male, Chinese and between the age of 20 and 49. More than 80% acquired HIV via sexual contact. The most common primary AIDS- defining illness was Pneumocystis carinii pneumonia (PCP), which occurred in 46 patients. Eight episodes of Penicillium marneffei infection have been recorded. Fifty-nine patients have received antiretroviral therapy whereas PCP prophylaxis was given to 47 patients. The mean CD4 count at HIV and AIDS diagnosis was 394/microliters and 121 /microliters respectively. Sixty-seven patients were known to have died at the time of the analysis. PCP was the most common cause of death, accounting for over one-fifth of the cases. The median survival after AIDS diagnosis was less than 2 months for cases reported in 1985-1987 and over 15 months for those of 1990-1991.

CONCLUSION

Pneumocystis carinii pneumonia was the most common initial AIDS-defining disease and cause of death in Hong Kong. Survival of the patients has gradually improved over the past few years.

A geriatric day hospital in Hong Kong: an analysis of activities and costs

A survey of the activities of a geriatric day hospital in Hong Kong was carried out. It revealed that alternative modalities of hospital-based treatment were impractical and difficult to organize. Most patients and their carers were satisfied with the day hospital service, and the main area for improvement was in transportation. Costs of day hospital treatment were also calculated, and were found to be cheaper than an equivalent period of in-patient rehabilitation or out-patient therapy.

Sol-gel silica laser tunable in the blue

Doped and undoped silica slabs were fabricated through the use of the sol-gel technique. Extended UV transmission was observed for HCl-catalyzed sol-gel silica. Under transverse pumping with a XeCl laser, narrow-linewidth (<0.9-nm) laser oscillation from silica slabs doped with coumarin 460 (C460) was achieved in a grating-resonator cavity configured in the grazing-indicence geometry. Tuning of the C460-doped silica laser extended from 468 to 494 nm. The conversion efficiency of the narrow-linewidth blue laser was 5.5%.