Delays in diagnosis and treatment of pulmonary tuberculosis in AFB smear-negative patients with pneumonia.

BACKGROUND: Diagnostic and treatment delays increase the severity and transmission of pulmonary tuberculosis (PTB). This study aimed to evaluate TB diagnostic and treatment delays in acid-fast bacilli (AFB) smear-negative patients. METHODS: This was a retrospective observational study. Patients with positive AFB culture of Mycobacterium tuberculosis complex (MTC) were selected from among hospitalised patients with a diagnosis of pneumonia. Admission ward, anti-tuberculosis treatment and the duration of AFB culture were compared between smear-positive and smear-negative patients. RESULTS: Of the 70 patients with positive isolation of MTC in AFB culture, 27 (38.5%) were smear-negative; of these, 18 (66.7%) were not isolated while in hospital, and 17 (63%) were neither diagnosed nor treated for TB. In contrast, 41 of the 43 smear-positive patients (95.3%) were directly admitted or quickly transferred to the isolation room and started on anti-tuberculosis treatment (P < 0.001). Samples from smear-negative patients required more time to grow MTC in AFB culture than those of smear-positive patients (23 days vs. 14 days, P < 0.001). Diabetes was significantly associated with AFB smear positivity, with an odds ratio of 12.2. CONCLUSIONS: Negative AFB smears caused significant diagnostic and treatment delay. Patients staying in the general ward were exposed to TB patients who were not diagnosed in time.

Experimental observation of stable bound solitons in a figure-eight fiber laser.

Temporal bound solitons are observed experimentally in a passively mode-locked figure-eight fiber laser with a dispersion-imbalanced nonlinear optical loop mirror (DI-NOLM). Soliton interactions are suppressed by use of a spectral bandpass filter, and Gordon-Haus timing jitter is eliminated with a DI-NOLM, which removes the cw light component in the laser cavity. The bound solitons are found to be stable for several hours in the laser cavity when no external perturbation is applied.

A review of Hib epidemiology in Asia.

Meningitis due to an invasive Haemophilus influenzae type b (Hib) infection, has been previously perceived to be relatively uncommon in Asia. However, the incidence of disease and its impact may have been underestimated. In addition to a lack of microbiological facilities in some hospitals, difficulties in culturing the organism and the widespread use of antibiotics may have hidden the true incidence of the disease in some countries. Furthermore, the reported disease burden probably underestimates the incidence of Hib pneumonia. The epidemiology of invasive Hib disease for various Asian nations is reviewed in this paper. Hospital-based studies show that Hib is a major cause of bacterial meningitis and/or pneumonia in the Philippines, India, Thailand, Malaysia, Indonesia and Vietnam. Singapore and Hong Kong have a low incidence of infection compared with Western and other Asian nations. This low incidence is not due to a higher level of natural protective antibodies, but may be related to an interaction between environmental and genetic factors. Therefore the widespread belief that Hib infection is unimportant in Asia does not refer to Asia as a whole and possibly to Chinese patients only, and failure to recognize this has serious implications. The inclusion of Hib vaccine in the routine infant immunization schedule in many industrialized nations has significantly reduced the incidence of invasive disease. Recent studies have shown Hib vaccination is also effective in preventing invasive disease in children in developing countries. While population-based data may be required to confirm the need for public-funded infant Hib immunization in Asia, its introduction in countries with a high incidence of Hib meningitis and/or pneumonia has the potential to significantly improve pediatric health and survival.

Hepatitis A virus: declining seroprevalence in children and adolescents in Southeast Asia.

The prevalence of hepatitis A virus (HAV) in a country largely reflects its standards of hygiene and socioeconomic conditions. Countries which undergo socioeconomic development show major change in HAV prevalence from high to low endemicity, and this is largely reflected in patterns of age-related seroprevalence. This paper presents age-related HAV seroprevalence patterns of SE Asian countries, and highlights how these patterns have changed over recent decades. Singapore, Thailand and Malaysia have experienced a decline in childhood and adolescent HAV seroprevalence, typical of countries which undergo socioeconomic development. By contrast, India has remained a country of high endemicity, with almost universal seroconversion in childhood. The Philippines and Vietnam show age-related seroprevalence patterns typical of high to moderate endemicity, while Indonesia shows significant regional variation in HAV seroprevalence. Populations within countries which exhibit major improvements in endemicity and age related HAV seroprevalence patterns are at risk of HAV epidemics, and a paradoxical increase in incidence tends to occur as seroconversion shifts from children to adults. The residents of these countries, a significant number of whom are at-risk, would benefit from a program of vaccination, as would non-infected individuals visiting high-risk areas.

Single-strand breaks in DNA of hamster and human cells exposed to methyl methanesulfonate and ultraviolet light.

The number of single-strand breaks produced in DNA after exposure to UV light or to methyl methanesulfonate (MMS) was additive when cells were exposed to both agents in close succession. Repair of the damage from either agent was partially inhibited by cytosine arabinoside, resulting in higher break frequencies under all conditions of exposure. Exposure to both agents followed by growth in cytosine arabinoside resulted in break frequencies that were approximately the same as the sum of those from each agent individually. These findings contrast with previous results in which pyrimidine dimer excision and repair replication after exposure to UV light were inhibited by MMS. These observations are not due to cell permeability changes after alkylation, but can be explained if the complex of excision-repair proteins is only partially inactivated by alkylation. Initial incisions to start repair would still occur but only limited amounts of repair replication would ensue without actual removal of the pyrimidine dimers.

Idiopathic acute fatty liver of pregnancy in 12 patients.

The clinical features, laboratory investigations and histopathology of 12 patients with idiopathic acute fatty liver of pregnancy are presented. Repeated vomiting, starting in the last trimester, was the cardinal symptom. Seven patients had proteinuria, hypertension and peripheral oedema before jaundice appeared. Caesarian section and induction of labour led to a lower than expected maternal mortality (33 X 3 per cent) and foetal mortality (66 X 7 per cent). There was a high incidence of twin and male births. Neutrophilia, thrombocytopenia and normoblasts were a uniform feature and uric acid levels were universally high. These findings may be useful in diagnosis in conjunction with liver function tests. Hepatic histology showed pathognomonic microvesicular fat in swollen hepatocytes with central nuclei and centrilobular distribution. However, a diffuse pattern and the presence of significant inflammation and fibrin deposits led to an initial misdiagnosis in two patients. Histology of fetal livers and five placentae was normal. Seven subsequent normal pregnancies occurred in four patients. Acute fatty liver of pregnancy may be confused with acute hepatitis or toxaemia on both clinical and histological grounds. Accurate diagnosis should lead to improved management and lessen maternal and fetal mortality. This justifies more intensive and urgent investigation of nausea, vomiting and jaundice in the last trimester of pregnancy.