Time dynamics of photon migration in semiopaque random media

The temporal behavior of femtosecond laser pulses propagating and scattering in random media was studied using an optical fiber probe and a streak camera. Information on the temporal profile of laser pulse scattering at 90 degrees in semiopaque media was analyzed. Apparent ballistic transport was observed for both single and multiple scattering regimes. A phantom (hidden foreign object) was identified in a semiopaque environment using time resolved techniques with a total optical density of ~3.

IgG subclass deficiency in children with recurrent infections

Serum IgG subclasses and IgG, IgA and IgM were measured in 35 patients with frequent infections and unusually severe infections, 45 normal children were compared. There is no significant difference between the geometric means of two age-matched groups (p greater than 0.05) and the proportion of low IgG subclass. We detected 9 cases with low IgG subclass in our selected patients, but we have 6 cases with low IgG subclass in our normal population without symptoms. For the low IgG subclass cases, total IgG level remain at normal age-related values, no IgA deficiency was found in our 78 cases. It is not uncommon to find low IgG subclass in Chinese children, but their significance is still questioned in our study. Larger number of cases should be collected and antibody response to antigen should be the goal for further study in Chinese children.

An epidemiological study of pityriasis rosea in Middle Road Hospital

Pityriasis rosea is a common skin disorder seen in dermatological practices. A one year prospective study on pityriasis rosea was carried out in Middle Road Hospital, Singapore. A total of 214 patients were studied. The incidence rates by age, sex and month were analysed. The peak incidence was in the 20-24 age group. There was a male predominance. More patients with pityriasis rosea were seen in the months of March, April and November. The clinical features in our patients concur with other studies. Blood for VDRL was done on 170 patients. Two had a biological false positive test. Total white counts were normal in 97.9% of specimens done. The rash lasted from 1 to 8 weeks in 84.4% of the patients with most patients suffering from the rash for 5 weeks.

Generalised exfoliative dermatitis--a clinical study of 108 patients

This study was to investigate the epidermiological, etiological, clinical and prognostic aspects of patients with Generalised Exfoliative Dermatitis in Singapore. From 1981 to 1985, all patients with exfoliative dermatitis or erythroderma admitted to our dermatology wards were included into this study. A standard protocol was filled in for each patient, and they were subsequently followed up at our out-patient clinics. There were 79 male and 29 female patients (sex ratio 2.7:1). The average age was 61.5 years. Most of the patients were from low social income groups. Apart from scaling and erythema, peripherial oedema was the most common finding (44%), followed by hair loss (25%) and lymphadenopathy (22%), 15% of patients had haemoglobin level 10G/dl. The main etiological groups were eczema/dermatitis, psoriasis, drug reactions and those with unknown causes. Two patients were suffering from congenital dermatoses. None of our patients was casually related to malignancy. This study suggested that GED was not a fatal disease among our patients, and they often had a good prognosis.

Hypertension in IgA nephropathy

Among 151 patients with IgA nephritis, 18/151 (12%) had hypertension at presentation and 50/151 (33%) were hypertensive after an interval of 65 +/- 40 (Mean +/- SD) months. Hypertensive patients (n = 50) had a higher incidence of glomerulosclerosis, medial hypertrophy of blood vessels, tubular atrophy, poorly selective proteinuria and extension of immunodeposits to peripheral capillary walls compared to normotensive patients (n = 101). Chronic renal failure occurred more commonly among hypertensives compared to normotensive patients (42%) versus 14%. However, the time taken for patients to reach renal impairment or end stage renal failure was not significantly different. The cumulative renal survival for the hypertensive group was 78% after 8 years compared to 91% in the normotensive group (p less than 0.05). In the second part of the study, patients who were hypertensive at presentation (n = 18) were compared with those who developed hypertension on follow up (n = 32). Apart from a shorter duration of follow up for patients with hypertension and a higher incidence of glomerulosclerosis, there were no significant differences in their clinical presentation, laboratory indices or other histological parameters. The incidence of chronic renal failure and the time taken to reach end stage renal failure were not different. Uncontrolled hypertension was an important cause for rapid deterioration to end stage renal failure within 3 years, compared to 8 years when hypertension was controlled.

Treatment of verruca vulgaris with intralesional bleomycin

From January 1985 to January 1986, a group of patients suffering from verruca vulgaris were treated with intralesional bleomycin in Middle Road Hospital. Each skin lesion was injected with 0.1% solution of bleomycin solution, up to a maximum of three injections per lesion. Patients were reviewed fortnightly for 6 weeks. Out of 35 patients who completed the study, 29 patients (83%) were initially cleared of their warts, and 3 patients had partial clearance. 3 patients had recurrence of lesions on follow-up. An average of 1.5 treatment sessions was required for each patient. Scarring and pigmentary changes at injection sites were minimal. No systemic side effects were observed. This study shows that intralesional bleomycin is a safe and effective method for treating viral warts.

Binding of calcium to glycosaminoglycans: an equilibrium dialysis study

Binding of calcium to the glycosaminoglycans (GAGs) heparin, chondroitin sulfate (CS), keratan sulfate (KS), and hyaluronic acid (HA) has been studied by equilibrium dialysis using exclusion of sulfate to correct for Gibbs-Donnan effects. Calcium binding occurs to all of these GAG species, suggesting that both sulfate and carboxylate groups are involved in cation binding. For all GAGs, the binding stoichiometry is consistent with a calcium-binding "site" consisting of two anionic groups. The order of calcium binding affinities is heparin greater than CS greater than KS greater than HA, and is critically dependent upon charge density; heparin binds calcium with 10-fold higher affinity than CS. The mode of calcium binding to GAGs is consistent with a recently proposed mechanism of growth plate calcification which states that cartilage proteoglycan functions as a reservoir of calcium for calcification of epiphyseal cartilage.

Ischiopagus tetrapus conjoined twins

Two sets of ischiopagus conjoined twins were successfully operated on at the University Hospital, Kuala Lumpur in 1981 and 1982. The anatomy of the organ and system malformations are discussed which determined the technique of reconstruction after surgical separation to obtain optimum cosmetic and functional results. Permanent colostomy was not required in any of the four twins and in only one twin was there a need for urinary diversion.

Epidemiology of meconium staining of amniotic fluid in Hong Kong

The characteristics of 94 patients with meconium stained amniotic fluid diagnosed during labour in the Prince of Wales Hospital, Hong Kong, from July to August 1984, were analysed. The incidence was 21.4% of deliveries. These patients were compared to a group of non-meconium patients (349 cases) in demographic and obstetric aspects. Patients in low social class and patients with antenatal and medical complications did not have a higher incidence of meconium staining of amniotic fluid. However, a history of previous spontaneous or induced abortion was significantly more common in the meconium group. The labour performance of these patients and the perinatal outcome are discussed.

Effect of calcium deprivation on the proliferation and ultrastructure of cultured human carcinoma cells

The ability of cells to proliferate in the presence of low extracellular calcium levels has been proposed as a marker for malignancy. To further evaluate this marker, the effects of extracellular calcium deprivation on proliferation and morphology in culture were examined in eight tumorigenic lines derived from human cancers. With calcium reduced from 1.8 mM (HCM) to 0.02 mM (LCM), the colony-forming ability remained unchanged in five lines, increased in line SK-BR-3, decreased partially in line C-4II, and was reduced to the level of nontumorigenic cells (by approximately 90%) in line C-4I. This atypical response of C-4I could not be accounted for by the presence of a subpopulation of nontumorigenic cells. In contrast to nontumorigenic cell, sparsely seeded C-4I cells adapted to growth in LCM with time. Like nontumorigenic cells, C-4I cells grew efficiently in LCM if seeded at high densities, suggesting that conditioned medium compensated for calcium depletion. The four tumorigenic lines with the least organized growth patterns in HCM changed least in shape, intercellular associations, cell surface, and cytofilaments upon exposure to LCM. Line C-4I, which in HCM expressed characteristics of stratified squamous epithelium, underwent the most drastic changes, including a redistribution of tonofilaments from the peripheral cytoplasm and contact regions to a perinuclear position. The results support the concept that most tumorigenic lines have reduced calcium requirements for proliferation. Exceptions, as illustrated by the limited colony-forming ability in LCM of the C-4I cells, may be related to the retention of a requirement for growth factors.

Morphological and functional differentiation of Kirsten murine sarcoma virus-transformed rat adrenocortical cell lines

This study was undertaken to examine relationships of the phenotype of malignant cells to target cell properties and to events early in the transformation process. Eighteen transformed lines were obtained by Kirsten murine sarcoma virus infection of cells from adrenal glands of rats ages 4 to 30 weeks, at first or second passages in culture. They were grown either as fibroblastic adrenocortical stem cells or as more differentiated epithelial cells, depending on culture conditions. Of 14 lines examined for their capacity to synthesize corticosteroids, 11 converted [14C]pregnenolone to progesterone, and one converted to deoxycorticosterone. In vivo, seven lines produced tumors resembling pleomorphic carcinomas, six lines grew as sarcomas, four grew as mixed tumors, and one line produced anaplastic tumors. Distinguishing features in culture of the carcinoma-producing lines were early onset and rapid progression of morphological transformation, a noncohesive epithelial cell form in some lines, lack of extracellular matrix, and, possibly, and origin in older animals. In contrast, sarcoma-producing cells were fibroblastic and cohesive, produced extracellular matrix, and transformed morphologically after longer and less well-defined periods in culture. The variation in histopathology was unrelated to the differentiation of the target cells and to the capacity of the transformed cells to synthesize corticosteroids. The results show that adrenocortical cells, transformed by Kirsten murine sarcoma virus after short-term culture, usually retain some functional differentiation and sometimes resemble human adrenocortical carcinomas histologically. The susceptibility of adrenocortical cells to Kirsten murine sarcoma virus raises the possibility that mesodermally derived epithelia in general may be target tissues for C-type sarcoma viruses.

Virions associated with acute gastroenteritis in Vancouver, 1976

Virions were identified by electron microscopic observation of unconcentrated extracts of feces obtained from 55 (33%) of 167 children aged 3 weeks to 5 years who were hospitalized with acute gastroenteritis at Children's Hospital, Vancouver between January and December 1976. Morphologic types included 30 rotavirus, 15 adenovirus, 5 astrovirus and 5 picornavirus-like particles.

Arbovirus growth in Aedes aegypti mosquitoes throughout their viable temperature range

After intrathoracic inoculation of laboratory-bred Aedes aegypti mosquitoes with 3 Yukon isolates of California encephalitis (CE) virus (showshoe hare subtype), Northway (NOR) and Murray Valley encephalitis (MVE) viruses, viral replication was observed following incubation at 13, 21, 35 and 39 degrees C, which constituted the full temperature range of viability of A. aegypti. Rates of viral replication were reduced at low temperatures and accelerated at high temperatures. Virus-specific immunoperoxidase staining of mosquito salivary glands occurred regularly after thoraces attained maximum infectivity levels. At 13 and 21 degrees C, mosquitoes were infected by 10 to 100 times less CE and MVE viruses than mice, but about 10 times more NOR virus was required to infect mosquitoes than mice.