Altered p53 expression and epidermal cell proliferation is seen in vulval lichen sclerosus

Aberrant p53 immunoreactivity has been found in skin pre-malignancies and dysplasias such as Bowen's disease and actinic keratoses. Vulval lichen sclerosus (LS) has been reported to be pre-malignant, with an association of vulval carcinoma in 3% to 6% of patients. In contrast, non-genital LS appears to have no malignant potential. In this immunocytochemical study, we investigated p53 expression in 10 cases of histologically proven vulval LS and 9 cases of non-genital LS using the murine monoclonal antibody Do-1 raised against recombinant human p53 which reacts with both wild-type and mutant p53. None of the vulval specimens had epithelial dysplasia or malignancy. Normal vulval (7 cases) and non-genital skin (5 cases) were used as tissue controls, respectively. The cell proliferation index was also studied using the MIB 1 monoclonal antibody which detects the cell-cycle associated Ki-67 antigen. The technique of microwave irradiation for antigen unmasking was employed on formalin-fixed and paraffin-embedded tissues. There was a significant increase in p53 immunoreactivity in vulval LS (32.13 +/- 15.11 epidermal cells per 100 basal cells) compared to normal vulval skin (7.52 +/- 5.04 epidermal cells per 100 basal cells) (p < 0.001), whereas the MIB 1 labelling index was lower in vulval LS (39.45 +/- 15.88 epidermal cells per 100 basal cells) than in normal controls (86.26 +/- 32.31 epidermal cells per 100 basal cells) (0.001 < p < 0.01). In contrast, there was no significant difference in p53 immunoreactivity or MIB 1 labelling index between non-genital LS and normal controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficient and rapid affinity purification of proteins using recombinant fusion proteases

In the affinity purification of recombinant fusion proteins, the rate-limiting step is usually the efficient proteolytic cleavage and removal of the affinity tail and the protease from the purified recombinant protein. We have developed a rapid, convenient and efficient method of affinity purification which can overcome this limitation. In one example of the method, the protease 3C from a picornavirus (3Cpro), which cleaves specific sequences containing a minimum of 6-7 amino acids, has been expressed as a fusion with glutathione S-transferase. The resultant recombinant 'fusion protease' cleaves fusion proteins bearing (from the amino-terminus) the same affinity tail as the fusion protease, a 3Cpro cleavage recognition site, and the recombinant protein of interest. The recombinant protein is purified in a single chromatographic step which removes both the affinity tail and the fusion protease. The advantages over existing methods include much improved specificity of proteolytic cleavage, complete removal of the protease and the affinity tail in one step, and the option of adding any desired amount of fusion protease to ensure efficient cleavage. The potential flexibility of the method is shown by the use of various affinity tails and alternative fusion proteases.

Immunological characterisation of the lichen planus infiltrate using monoclonal antibodies

The immunological typing of cell populations in the skin biopsies of 20 cases of histologically proven lichen planus was done using monoclonal antibodies. The Avidin-Biotin-Complex immunoperoxidase technique was used. A predominance of T-helper/inducer cells in the dermal infiltrate was observed by a semiquantitative analysis. T-suppressor/cytotoxic cells and Langerhans cells were increased compared to eczema lesions. A comparison of the staining of Langerhans cells using monoclonal antibodies and the S100 protein stain showed that more Langerhans cells could be identified with the CD1 monoclonal antibody. The type of infiltrate did not correlate with the duration of disease. Direct immunofluorescence staining demonstrated fibrinogen at the dermo-epidermal junction and/or colloid bodies in the upper dermis. The immunophenotyping and immunofluorescence pattern in local cases of lichen planus are similar to previous reports from other countries. An interesting finding was the unexplained disproportionate predominance of Indians in the study cohort.

During negative regulation of the human papillomavirus-16 E6 promoter, the viral E2 protein can displace Sp1 from a proximal promoter element

The principal early promoter of human papillomaviruses (HPVs), designated P97 in the case of HPV-16, contains four characteristically aligned cis-responsive elements, namely one binding site for Sp1, two for the viral E2 proteins, and the TATA box. The Sp1 binding site is needed to mediate activation of P97 by the remote epithelial-specific enhancer, and the two E2 binding sites contribute to a negative feedback-loop of viral gene expression. The Sp1 consensus motif and the TATA-box distal E2 binding site are spaced in all genital papillomaviruses by a single nucleotide. We show here that at physiological concentrations, the binding of E2 proteins and Sp1 are mutually exclusive events, since a bandshift analysis with nuclear extracts from ID13, a mouse cell line transformed by BPV-1, showed only the E2 or the Sp1 bandshift, but no complex indicative of the concomitant binding of both factors. Increasing concentrations of in vitro translated E2 protein compete efficiently with the Sp1 factor for binding to an oligonucleotide containing both binding sites. Interference between Sp1 and E2 protein binding is apparently relevant for P97 repression in vivo, since a mutational analysis revealed that both E2 binding sites are necessary for negative transcriptional regulation: Alone, neither the distal site, where E2 protein can induce Sp1 displacement, nor the proximal site, where E2 protein interferes with formation and function of the pre-initiation complex, have a significant effect, but two functional E2 binding sites lead to repression of P97.

Synaptic junctions between sympathetic axon terminals and pinealocytes in the monkey Macaca fascicularis

The distribution of axon terminals in the pineal gland of monkeys was studied by electron microscopy. Numerous terminals bearing small pleomorphic agranular and dense-cored vesicles were localized in the perivascular space and among the pinealocytes in the parenchyma in normal monkeys. Following bilateral superior cervical ganglionectomy, they underwent degenerative changes, including the accumulation of glycogen masses, appearance of dense residual bodies and the displacement of synaptic vesicles. Some of these degenerating terminals showed synaptic contacts with the cell bodies of pinealocytes. At the synaptic junction the postsynaptic membrane was thickened asymmetrically. Examples of synaptic contacts were most frequently observed in 5 and 7 days postoperative animals. In the longer surviving (30 days) monkey, most of the axon terminals showed round agranular vesicles, and they were mainly presynaptic to the intrapineal ganglion cells with some of the pinealocytes. They remained structurally unchanged following the resection of both the superior cervical ganglia. A few axon terminals containing small dense-cored vesicles appeared to have survived the initial insult, but some of their vesicles appeared swollen 30 days after the operation. It is concluded from this study that some of the pinealocytes are under the influence by the postganglionic neurons in the superior cervical ganglia through direct synaptic contacts. The intrapineal ganglion cells are postsynaptic to fibres originating exclusively from the central nervous system. Some of these fibres, however, may be presynaptic directly to pinealocytes.

Cyclic AMP is one of the intracellular signals during the mating of Chlamydomonas eugametos

Chlamydomonas eugametos gametes of opposite mating type make cell-cell contact via their flagellar surfaces. This contact triggers an increase in the intracellular level of cyclic AMP (cAMP) and several cellular responses which are necessary for cell fusion. Here, we show that wheat-germ agglutinin, which binds to the flagellar surface and induces all mating responses, also increased the intracellular cAMP level. Dibutyryl-cAMP added to non-mating gametes induced flagellar twitching, cell-wall lysis, mating-structure activation, flagellartip activation and an increase in agglutinability. It did not induce agglutinin transport to the flagellar tip (tipping) and may not be the direct cause of flagellar twitching and flagellar-tip activation. In non-illuminated cells, dibutyryl-cAMP was far more effective in evoking mating reactions than in illuminated cells. Light induced a 50% decrease in the cAMP level within 1 min. Adenylate cyclase was found to be associated with cell membranes but only 8% of the total was present in the gamete flagella.

Basal cell carcinoma of the head and neck region--a five-year study (1984-88)

Two hundred and seventy-two patients with 292 lesions of basal cell carcinoma of the head and neck region treated at the Department of Plastic Surgery, Singapore General Hospital over a period of five years, were reviewed. Basal cell carcinoma is common in the face, the lesser pigmented mongoloid race of our population and has a higher incidence in the elderly age group. A large number (63%) of the basal cell carcinoma are of the pigmented variety, a very unusual feature. The commonest site of occurrence is the nose (37%). Of the 292 basal cell carcinoma excised, 27 (9%) had tumour involvement of the margins of excision. However, of these 27 cases, only 4 have presented with recurrent tumour. The place of close observation and immediate re-excision of positive margins is discussed. The 4 cases of recurrent basal cell carcinoma involved the nose and lip area, areas with a known higher incidence of recurrence. The results of treatment (98.7% cure rate) of this group are encouraging and compares well with those of other series and using other modalities of treatment. Longer follow-up is required.

Oculocardiac reflex in strabismus surgery under general anaesthesia--a study of Singapore patients

A study of 80 patients with strabismus undergoing correctional surgery under general anaesthesia was done. A comparison was made with regards to the incidence of oculocardiac reflex between patients premedicated with intramuscular atropine 0.015 mg/kg and non-premedicated patients. We found that premedication with atropine reduces the incidence and the morbidity of the oculocardiac reflex.

Ultrastructure of interstitial cells of Cajal at the gastro-oesophageal junction of the monkey (Macaca fascicularis)

The ultrastructure of the interstitial cells of Cajal (ICC) in the oesophagus of the monkey resembled that described in the oesophagus of other mammalian species but differed in their paucity and almost lack of smooth endoplasmic reticulum, caveolae and filaments. The plasmalemma of the ICC was in close contact (20- to 30-nm gaps) with that of smooth muscle cells. This may occasionally take the form of a desmosome, but gap junctions have not been observed. Vesiculated axon profiles, containing large granular or agranular vesicles were in close contact (20- to 30-nm gaps) with the plasmalemma of ICC. In a few vesiculated profiles a presynaptic density could be recognized. The intercalation of the ICC between the vesiculated axon profiles and the smooth muscle cells suggest a role in oesophageal motility. Between 3 and 21 days following bilateral vagotomy some ICC showed regressive changes such as increased electron density and shrinkage of the cytoplasm, crowding of the organelles and dissolution of the nuclear chromatin material. Axon profiles in the vicinity of the affected ICC contained glycogen granules suggesting injury. In late stages, the number of ICC and smooth muscle contacts was reduced. The results suggest that the vagus nerves exert a trophic influence on the ICC and that the intercellular relationships between ICC and smooth muscle cells possess a degree of plasticity. It is tentatively suggested that these vagal effects may be mediated via the oesophageal myenteric ganglia.

Monitoring of diabetes in children

There is increasing evidence to show that a high degree of metabolic control in diabetes mellitus delays and reduces the severity and incidence of the microvascular complications of diabetes. The goals of appropriate therapy for diabetes should hence include an all-out effort to achieve as near normal metabolism as possible but it should be individualized accordingly. In actual practice it is difficult to achieve "good" control especially in diabetic children without attendant hypoglycaemia and its sequelae. Diabetic control is difficult to define in clinical terms, and the maintenance of metabolic control in diabetes involves a complex interaction of pathological, physiological, psychological, familial, social and environmental variables. The aims in insulin-dependent diabetic children is to ensure optimal emotional and physical health of the child or adolescent. The various modalities available for monitoring or assessment of diabetic control shall be discussed.

HLA Bw46 and DR9 associations in Graves' disease of Chinese patients are age- and sex-related

The HLA-A, -B antigens in 159 Chinese patients with Graves' disease were compared with those of 330 controls. The HLA-DR antigens of the patients were also studied in 100 normals. Analysis of the increased prevalence of Bw46, according to the sex and age of onset of disease of the patients, showed that the strong association of Bw46 resided with male patients (n = 58), Pc = 0.0000052, RR = 4.2. Although the frequency of Bw46 was also increased in female patients (n = 101), it was statistically not significant. For the DR9 antigens, the strong association with male patients was also observed, viz. Pc = 0.019, RR = 3.2. Males also had higher risks of Graves' disease if they had homozygous Bw46 at presentation. Further analysis by age of onset of disease revealed the segregation of significant association with Bw46 for the males at 1-19 yr, Pc = 0.0011, RR = 17.5 HLA associations (Bw46 and DR9) with Graves' disease in Chinese are observed primarily in males, especially those whose known ages of onset of the disease are between 1-19 yr (Bw46).

Ultrastructure of the pineal gland of the monkey, Macaca fascicularis, with special reference to the presence of synaptic junctions on pinealocytes

The present study described the normal ultrastructure of the monkey pineal gland. The gland was composed of the principal pinealocytes, intramural neurons and glial cells. The nucleus of the pinealocytes was deeply infolded with evenly distributed chromatin materials. The abundant cytoplasm was rich in organelles including the well-developed Golgi apparatuses, multivesicular bodies, dense-cored vesicles and widely scattered free and polyribosomes. A variety of axon terminals was observed and the majority of them contained pleomorphic agranular vesicles with a few large dense-cored vesicles. A few terminals showed flattened vesicles or small dense cored vesicles. Some of the axon terminals formed synaptic contacts with the cell bodies of pinealocytes. These synapses were mainly concentrated in the posterior third of the gland. The occasional intramural neurons observed were postsynaptic to axon terminals containing round agranular vesicles. The sources of the nerve fibres and terminals forming synaptic junctions with pinealocytes and intramural neurons were discussed.

Ethnicity and drug use: a critical look

The present study addresses two limitations of the literature regarding the ethnicity-drug use relationship, namely, the absence of ethnically diverse samples and also the inadequate control of background variables. The data employed consisted of responses from 3,697 students derived from a single-stage probability survey from which eight ethnic groupings were constructed: (1) Eastern European, (2) Western European, (3) British Isles, (4) Black, (5) Oriental, (6) East/West Indian, (7) Jewish, and (8) Mediterranean. The findings reveal that, first, the significant zero-order ethnicity effect for alcohol use did not attenuate after controlling for background variables. Also, this relationship was not conditional upon other independent variables. Second, for other substance use measures, the significant zero-order ethnicity effect was found to be spurious or conditional.

Congenital hypothyroidism in Singapore: prescreening era

Early diagnosis and treatment is extremely important in patients with congenital hypothyroidism to prevent mental retardation. Late diagnosis in children with congenital hypothyroidism results in a poor developmental outcome with low IQ and poor educational and occupational abilities. General practitioners and paediatricians should try to diagnose congenital hypothyroidism early, so that treatment can be initiated as soon as possible. The importance of a neonatal screening programme for congenital hypothyroidism is emphasized.

Malabsorption of oral antibiotics in humans and rats with giardiasis

We observed unexplained treatment failures in 13 patients with serious infections and apparent incidental giardiasis. Antibiotic concentrations were assayed in the serum from patients before initiating anti-Giardia therapy and again 2 to 3 weeks after therapy. The peak serum concentrations of antibiotics were higher after treatment for giardiasis. The rat model of giardiasis was used to examine the hypothesis that oral antibiotics are malabsorbed during Giardia lamblia infection. Twenty-eight-day-old Sprague-Dawley rats were fed amoxicillin (50 mg/kg/dose), ampicillin (50 mg/kg/dose), cefaclor (50 mg/kg/dose), cephalexin (50 mg/kg/dose), erythromycin (50 mg/kg/dose), penicillin V (50 mg/kg/dose) or sulfamethoxazole (20 mg/kg/dose) and sera were assayed for antibiotics at 1, 2, 4, 6 and 12 hours after therapy. The same rats were fed 10(5) G. lamblia cysts on 4 consecutive days. On Day 7 of infection the rats were fed the same antibiotic and sera were assayed for antibiotics at 1, 2, 4, 6 and 12 hours after therapy. The mean peak serum concentrations for all drugs except sulfamethoxazole were significantly higher in the rats before infection with G. lamblia. These data suggest that oral antibiotic therapy maybe compromised by decreased absorption in the presence of giardiasis.

Relapse markers in childhood thyrotoxicosis

Childhood thyrotoxicosis is not an uncommon illness, but there is a considerable relapse rate in these patients on medical treatment. An attempt is made in this study to identify those markers that are predictive of a tendency to relapse in childhood thyrotoxicosis. A total of 32 patients with Graves disease were included in the study. Several features were correlated with a tendency to relapse. Of these features, sex, family history, and antibody status were not significantly correlated to relapse. However, of 17 patients with goiter size two times normal or larger, 16 relapsed in comparison with seven relapses of 15 patients with goiter size less than two times normal (p = 0.0039). Of eight patients without ophthalmopathy, only two relapsed, while 21 patients of 24 patients with ophthalmopathy, relapsed (p = 0.002). Of 13 patients with serum thyroxine levels below 20 mcg/dl, six relapsed; of the 19 patients with serum thyroxine levels above 20 mcg/dl, 17 relapsed (p = 0.039). Among 24 patients with a previous relapse, only one achieved a remission with a second course of treatment. The remaining 23 patients had recurrent relapses. Hence it was found that goiter size, presence of ophthalmopathy, total thyroxine levels, and a previous relapse correlated significantly with a further relapse.

Glucose tolerance test and insulin levels in children with transfusion-dependent thalassaemia

Blood glucose and serum immunoreactive insulin levels were measured following an oral glucose load in 20 unrelated children with multiple transfused thalassaemia. Results suggest that even though overt diabetes and glucose intolerance are uncommon before the age of 13 years, the presence of insulin resistance is evident, especially in those who have been splenectomized.

Microangiopathy in Singapore diabetic children

Nineteen children with insulin-dependent diabetes mellitus were assessed for microangiopathic complications in the University Department of Paediatrics, Singapore. Of 17 who underwent nerve conduction studies, all showed impaired nerve conduction velocities, with more sensory than motor nerve involvement. The extent of neuropathy was significantly correlated with the duration of disease. Of five children who showed significant proteinuria, two had impaired creatinine clearance, two had cataract formation, and two retinopathy, in one background and in one proliferative. Our study showed a high prevalence of microangiopathic complications in these diabetic children and it is hoped that improved blood glucose control, with the aid of home blood glucose monitoring, may minimize or arrest the microangiopathic complications.

Assessment of complications in children with insulin-dependent diabetes mellitus

Nineteen children with insulin-dependent diabetes mellitus in the University Department of Paediatrics were assessed for complications of diabetes. 36.8% showed marked growth stunting, and half of the patients who attained puberty had a delayed onset of puberty. 42% showed limited joint mobility. Almost all the patients developed hypertrophic lipodystrophy while only 5 patients developed reversible lipoatrophy. Abnormal nerve conduction velocities were found in all 17 patients tested, with more of sensory nerve involvement. A significant correlation was found between duration of disease and the extent of neuropathy. Evidence of nephropathy was found in 5 patients, 2 of whom showed impaired renal function. One patient had background retinopathy, another had proliferative retinopathy and 2 patients developed cataracts. The high prevalence of microangiopathic complications in these children is probably related to their previous poor diabetic control and it is hoped that with home blood glucose monitoring to improve their control, these complications may be arrested or minimized.

HLA and insulin dependent diabetes mellitus in Singaporean Chinese

Singaporean Chinese IDDM was significantly associated with AW33, BW58, DR3 and DR4. AW33, BW58 and DR3 being in strong linkage disequilibrium among the Chinese, were associated most strongly with IDDM whose onset was less than or equal to 10 years. The strength of this association showed a significant inverse relationship with age of onset. The frequency of DR4 was significantly elevated on in the 11-20 year IDDM group. The importance of DR3 in Chinese IDDM was also reflected in the observations of joint occurrences of DR antigens. In the less than or equal to 10 years subgroup, the significant association were either DR3/DRW9, DR3/DR4 or DR3/BLANK. In the 11-20 years subgroup, DR4 appeared to be more important and DR4/DR3 and DR4/BLANK were strongly associated with IDDM in this subgroup.

HLA-DR antigens in Chinese children with insulin-dependent diabetes mellitus

We studied the distribution of HLA-DR and MT1, MT2, MT3 genotypes in 23 Chinese children with insulin-dependent diabetes mellitus (IDDM). The frequency of DR3 was 48% in IDDM children compared to 14% of normal controls (corrected p = 0.0098, RR = 5.70). The frequency of DR4 was not increased. These differences when compared with the results of Western populations may contribute to the relative rarity of IDDM among Chinese children.