Recurrent Potter's syndrome in a consanguineous marriage.
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Journal Article↗
Biomedical subjects
K B Lim
Publications and source records attributed to K B Lim.
Stability enhancement for peptide analysis by electrospray using the triple quadrupole mass spectrometer.
Electrospray ionization sources, used with triple quadrupole mass spectrometers from PE/Sciex (API III+), Micromass (Quattro II), and Finnigan (TSQ 7000), were modified with a 35-gauge stainless steel needle. The dimensions of the needle were 63 microm i.d. by 145 microm o.d. with variable length, depending on the specific instrument. This modification led to enhanced signal stability, improved signal/noise ratios, and lowered sample consumption for a wide range of peptides. Stable baselines were observed with flow rates in the range of 50 nL/min to 5 microL/min. An alternative design, based on a metal wire housed within a fused silica capillary, led to the most stable signals of all during infusion, but caused excessive peak broadening with capillary chromatography. The Finnigan interface was further modified with an external postcolumn addition tee, used in conjunction with capillary liquid chromatography columns of 30 and 50 microm internal diameter. The best results with the modified Finnigan interface were acquired using the 50-microm column at a flow rate of 150 to 200 nL/min.
Factor VII↗
Regulation of lipid A modifications by Salmonella typhimurium virulence genes phoP-phoQ.
Bacterial pathogenesis requires proteins that sense host microenvironments and respond by regulating virulence gene transcription. For Salmonellae, one such regulatory system is PhoP-PhoQ, which regulates genes required for intracellular survival and resistance to cationic peptides. Analysis by mass spectrometry revealed that Salmonella typhimurium PhoP-PhoQ regulated structural modifications of lipid A, the host signaling portion of lipopolysaccharide (LPS), by the addition of aminoarabinose and 2-hydroxymyristate. Structurally modified lipid A altered LPS-mediated expression of the adhesion molecule E-selectin by endothelial cells and tumor necrosis factor-alpha expression by adherent monocytes. Thus, altered responses to environmentally induced lipid A structural modifications may represent a mechanism for bacteria to gain advantage within host tissues.
Acylation↗
Initial studies of a new approach to the design and use of enzyme-based reactor/sensor systems: amperometric system for glucose.
This paper describes the development and evaluation of a new approach to the design and use of enzyme-based reactor/sensor systems (so-called "enzyme electrodes"). In the new approach, the reactor/sensor design is such that the measured response corresponds to reaction of all substrate in a fixed volume of solution. The result is that equilibrium-based measurements can be made, which in turn should result in advantages such as extended linear ranges and reduced dependencies on experimental variables such as enzyme activity, temperature, activators, inhibitors, etc. The concept was implemented with a glucose oxidase/electron-mediator reactor system immobilized on a glassy-carbon electrode operated in an amperometric mode. The reactor/sensor system was used in a thin-layer (14 microns) cell such that the mean diffusion time of substrate (glucose) across the cell was very short (< 1 s) and the rate-limiting process was the chemical reaction at the reactor surface. In this way, it was possible to quantify the electrical charge corresponding to reaction of all the substrate in a fixed volume of solution perpendicular to the plane of the reactor system. Because the determined charge is dependent only on the total amount of substrate in the fixed volume, results exhibit linear range up to at least 2-fold the Michaelis constant and reduced dependency on pH relative to results obtained with steady-state responses from the same experimental system. A mathematical treatment is presented which yields equations that are consistent with time-dependent responses for current and charge and which provide a rational basis for several data-processing options evaluated.
Biosensing Techniques↗
Error-compensating kinetic method for enzymatic determination of DNAs.
We describe the adaptation and evaluation of an error-compensating method for kinetic determinations of deoxyribonucleic acids (DNAs). The DNA is first reacted with ethidium bromide to produce a fluorescent intercalation complex. Subsequent treatment of the complex with DNase catalyzes hydrolysis of the DNA, causing a time-dependent decrease in fluorescence, which is monitored. A model for two-component parallel first-order processes is fit to the decay curve to predict the total change in fluorescence expected if the process were monitored to equilibrium. The predicted change in fluorescence response varies linearly with DNA concentration with an intercept corresponding to 0.13 mg/L DNA. Results by the predictive method are 47-, 58-, and 250-fold less dependent on DNase activity, temperature, and ethidium bromide concentration, respectively, than are results for an initial-rate method utilizing the same data. Moreover, the predictive method yields a significantly wider linear range than the initial-rate method, and is much less affected by blank fluorescence and RNA interference than is an equilibrium method based on the reaction of DNA with ethidium bromide alone.
Calibration↗
Bacampicillin to treat non-gonococcal urethritis in men: pilot study.
Of 84 men with non-gonococcal urethritis (NGU), 24 yielded Chlamydia trachomatis by either cell culture or MicroTrak immunofluorescence test. All 84 were treated with bacampicillin 800 mg twice a day for seven days. Five (one chlamydia positive) defaulted from follow up 10 to 14 days after the start of treatment. Of the 23 chlamydia positive patients who attended follow up, 22 became chlamydia negative; 14 of the 23 patients also became asymptomatic and had normal urethral smears. Of the 56 chlamydia negative patients who attended follow up, 21 were cleared of their urethritis. Two patients reported side effects; one drowsiness and one mild diffuse alopecia. Bacampicillin may therefore be a safe and effective alternative to tetracycline or erythromycin in treating chlamydial urethritis in men.
Adolescent↗
Dedifferentiated chondrosarcoma metastasizing to the pancreas in pregnancy.
Acute abdomen in pregnancy can present difficulties in both diagnosis and treatment. In this patient the presentation of an acute abdomen was due to some intraperitoneal hemorrhage complicating a pancreatic metastasis from a primary dedifferentiated chondrosarcoma arising from the right iliac bone. Neither the primary nor the secondary growths had been suspected previously.
Adult↗
Epidemiology of acute epididymo-orchitis in Singapore.
A prospective study on 55 patients with acute epididymo-orchitis was studied. Their ages ranged from 15 to 65 years. Thirty-three (60%) were within the 20-29 year age group and 9 were above 35 years of age. 69% cited prostitutes as the source of sexual contact. Twenty-six patients did not receive and 29 patients received antibiotic therapy before recruitment. In the former untreated group, 6 patients (23%) had gonococcal urethritis, 3 patients (11%) had chlamydial urethritis and 2 patients (8%) had combined gonococcal and chlamydial urethritis. No pathogens were isolated from the urethra from the remaining 15 (58%) patients, 8 of whom had nonspecific urethritis. In the latter treated group, 4 patients (14%) had gonococcal urethritis and no organisms were isolated from the remaining 25 (86%) of whom 6 had non-specific urethritis. None of the 55 patients had urinary tract infections. Forty-three patients (78%) had unilateral involvement of both the testis and epididymis, and 4 patients (7%) had bilateral epididymo-orchitis. Semen analysis was performed on 13 patients of whom 8 showed pyospermia.
Acute Disease↗
Comparative double-blinded study between mupirocin and tetracycline ointments for treating skin infections.
A double-blinded study was conducted to compare the effects of mupirocin and tetracycline ointments in the treatment of skin infections. 111 patients were available for clinical assessment, of which 53 were treated with mupirocin and 58 treated with tetracycline. Clinically, both groups were improved, and there was no significant difference. Bacteriological assessment however revealed a better response to mupirocin. Staphylococcus aureus and Streptococcus pyogenes were the most common organisms isolated. 99% of Staphylococci were sensitive to mupirocin compared with 61% to tetracycline and 29% to penicillin G. 57% of Group A beta haemolytic Streptococci were resistant to tetracycline compared to 14% to mupirocin. Gram-negative organisms were mostly resistant to both preparations. No side effects were observed in both treatment groups. This study suggests that mupirocin is a safe and effective topical preparation for treating most of our common skin infections.
Adolescent↗
Chlamydial infection in female prostitutes in Singapore.
Three studies conducted in 1982, 1985 and 1988 investigated chlamydial infections in female prostitutes. In 1982, 115 prostitutes with culture-positive gonorrhoea were studied; 8% were coinfected with Chlamydia trachomatis. In 1985, 86 female prostitutes and in 1988, 100 female prostitutes attending for routine tests were examined. Chlamydia trachomatis was isolated in 12% and 9% of the cases, respectively. Gonorrhoea was detected in 10% and 11% of the cases. In the 1988 study, one (9%) of the 11 women with gonorrhoea had concomitant chlamydial infection. Syphilis was diagnosed in 3% of the female prostitutes investigated in 1988. Our findings indicate that concomitant chlamydial infection occurs in about 8-9% of female prostitutes with gonorrhoea and that 9-12% of the female prostitutes screened harboured Chlamydia trachomatis in their endocervices. A chlamydial control programme in prostitutes is desirable.
Chlamydia Infections↗
Endocervical chlamydial infection in female contacts of patients with nongonococcal urethritis.
Eighty-five female contacts of patients with nongonococcal urethritis attending Middle Road Hospital were examined. Chlamydia trachomatis was isolated from the cervix in 39% of them. Forty-five per cent of the chlamydia-positive patients were asymptomatic and 79% of them showed signs of a cervicitis. None of the patients developed complications. Neisseria gonorrhoeae was not isolated from any of the patients. Clinical markers other than cervicitis are not useful for detecting chlamydial infections in female contacts of NGU. Until such time when cheaper, more convenient and accurate methods of laboratory diagnosis of C. trachomatis are put to routine use, it would seem prudent to treat all female contacts of NGU patients after exclusion of other sexually transmitted diseases.
Adolescent↗
Endocervical chlamydial infection in women attending a sexually transmitted disease clinic in Singapore.
Two hundred women attending the sexually transmitted disease (STD) clinic at Middle Road Hospital were investigated. Chlamydia trachomatis was isolated from 32% of women who were contacts of men with nongonococcal urethritis, 15% of contacts of gonococcal urethritis, 27% of contacts of unspecified STD, and 13% of women without any history of STD in their sex partners. Overall, Chlamydia trachomatis was isolated from 17% of 200 women, Neisseria gonorrhoeae from 13% of 199 women, Candida albicans from 34% and Trichomonas vaginalis from 6% of 197 women. Three per cent of the patients had positive VDRL results. A history of bilateral lower abdominal pain and the presence of cervicitis were significantly associated with chlamydial infection. Forty one per cent of the 34 chlamydia-positive women were asymptomatic. The results of this study show that C. trachomatis infection is more common than infection with N. gonorrhoeae in women who attend STD clinics. The need for routine screening and treatment on the basis of epidemiological and clinical markers of infection has to be carefully examined.
Adolescent↗
Endocervical chlamydial infection in women with gonorrhoea.
Eighty six women attending Middle Road Hospital with endocervical gonococcal infection were evaluated. Chlamydia trachomatis was isolated in 27% of them. Women co-infected with C. trachomatis were similar to those with gonococcal infection alone in terms of demography, type of sexual contact, previous sexually transmitted disease, genitourinary symptoms, and clinical signs.
Chlamydia Infections↗
Enzyme immunoassay (Chlamydiazyme) for the detection of chlamydial antigen in endocervical specimens.
Endocervical swabs taken from 86 women were tested by the Chlamydiazyme enzyme immunoassay test to detect chlamydial antigens. Compared to cell culture, Chlamydiazyme was 100% sensitive and 90% specific. This test is suitable as alternative diagnostic method to cell culture and has the potential for automation.
Antigens, Bacterial↗
Lack of effect of dimethyl sulphoxide (DMSO) on amyloid deposits in lichen amyloidosis.
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Adult↗
An unusual case of varicella involving the penis.
An unusual case of varicella involving the penis is presented. Herpetiform ulceration of the penis in a person who has had promiscuous sexual contact is not necessarily herpes progenitalis, since varicella may also involve the penis.
Adult↗
An immunofluorescence study of lichen planus among Asians in Singapore.
Forty-five Asian patients (Indians 35, Chinese 8, Malay 2) with histologically proven lichen planus were studied by immunofluorescence. The most characteristic feature, seen in 93% of the cases, was shaggy deposition of fibrinogen along the basement membrane. Immunoglobulin deposition along the basement membrane was notably, absent. Colloid bodies were observed in 87% of the cases. Fibrinogen was the most common immunoreactant, and its presence in colloid bodies was always associated with fibrinogen deposition along the basement membrane zone. Colloid bodies also contained a variety of other immunoreactants. However, staining for IgM was noted to be the most intense. The combination of shaggy deposition of fibrinogen along the basement membrane, in the absence of immunoglobulins, and the presence of colloid bodies around the basement membrane zone, is highly characteristic of lichen planus. The pattern of immunofluorescence among Asians with lichen planus, conforms to that observed in other races. There did not appear to be any difference in the immunofluorescence staining with pattern in the three racial groups studied.
Adolescent↗
Lichen planus: a study of 72 cases in Singapore.
Seventy-two patients attending this hospital with a diagnosis of lichen planus were examined. There was a striking predominance of Indians (69%) and a surprisingly low incidence of Chinese (24%) and Malays (4%) in the study population, compared to the racial composition of the general clinic population. The age distribution curve of the study population was bimodal with peaks at age groups 21-30 (22%) and 41-60 (33%) years. The most common morphologic variant was lichen planus vulgaris (common type) which we observed in 46 (64%) patients, followed by lichen planus hypertrophicus in 8 (11%) and lichen planus atrophicus in 2 (3%). Lichen planus confined to the skin was observed in 49 (68%) patients. Mucous membrane involvement was seen in 21 (29%)-17 (24%) had oral mucosa membrane involvement and 4 (6%) genital mucous membrane involvement. In 16 (22%) cases, mucous membranes were exclusively involved--12 (17%) had oral mucous membrane involvement and 4 (6%) genital mucous membrane involvement. Nail changes were only observed in 2 (3%) patients. Eight (11%) patients had associated diabetes mellitus. Overall, lichen planus appeared to pursue a protracted course with only 4 (6%) patients clearing completely after a disease duration of 5-12 months.
Adolescent↗