Biomedical subjects

L C Low

Publications and source records attributed to L C Low.

At least 37 records · Page 2Linked to original sources

PubMed1997

Ileoileocolic intussusception in children: diagnosis and significance.

The ileoileocolic type of childhood intussusception is difficult to diagnose pre-operatively and is associated with increased morbidity. This study describes the clinical and imaging features of 10 consecutive ileoileocolic intussusceptions diagnosed ultrasonically in 10 patients over a 36 month period. Ultrasound-guided hydrostatic reduction using Hartmann's solution was attempted in all 10 patients. Clinical and imaging features were compared with those of 28 ileocolic intussusceptions in 25 patients diagnosed and treated using the same methods during the same period. Most of the clinical and plain radiographic features of the patients with the ileoileocolic and ileocolic types of intussusception were similar. The two types of intussusception had the classical doughnut or pseudokidney, or both, signs on pre-reduction ultrasound scans. During the reduction process, when surrounded by fluid within the caecal lumen, the ileoileocolic type of intussusception had a typical complex appearance due to frond-like loops of intussuscepted small bowel. This finding was present in all cases. The hydrostatic reduction rate was only 10% (1/10) for ileoileocolic intussusception, compared with 92.9% (26/28) for the ileocolic type. All unsuccessfully-reduced cases underwent surgery, with surgical confirmation of the intussusception type in all cases. Only one patient was found to have a lead point, caused by a Meckel's diverticulum. In conclusion, the diagnosis of ileoileocolic intussusception can be made pre-operatively and these patients require surgical management.

Child↗

PubMed1996

Born small for gestational age: consequences for growth.

A large number of studies have documented a strong correlation between size at birth and subsequent height, although the reported incidence of catch-up growth and consequently the impact on final height has varied with time and between countries. These variations may be real, but could also be related to a number of methodological problems. The aim of this study was to explore two important aspects related to postnatal growth after disturbed fetal growth: first, the definition of small for gestational age (SGA), including the selection of cut-off points in defining shortness; and, secondly, the importance of the general socio-economic status of the population with regard to the incidence of growth faltering in early life. Data were analysed from two longitudinal population-based studies, one from Sweden and one from Hong Kong. Of the Swedish cohort, 3.8% had a birth length below -2 SD scores; in the Hong Kong population the corresponding value was 11.9% (Swedish reference values were used in both studies). The following conclusions were made. Size at birth is important for postnatal growth, and the difference in length at birth of 9-10 cm between the two extreme birth length subgroups remains, on average, until maturity. This seems to be true for the two study populations with different degrees of socio-economic development. However, the rate of catch-up growth is highly dependent on the definition of SGA, on the rate of catch-up growth in early life and on the incidence of growth faltering between 6 and 18 months of age.

Adolescent↗

PubMed1996

An episode of syncope attacks in adolescent schoolgirls: investigations, intervention and outcome.

An increasing number of students in a secondary convent girls school developed syncope attacks over a time course of about two months. Fourteen students who suffered from syncope and 12 other students from the same class with no symptoms were assessed by a team of psychologists and paediatricians with the aim of identifying the cause of the problem and to formulate possible remedial action. Psychological assessments included a mental state examination, developmental, personal and psychological history, state-trait anxiety, self-esteem, hypnotic suggestibility, and students' beliefs about the cause and nature of the syncope attacks. Physical investigations included physical examination, blood pressure and electrocardiogram. The results indicated that most participants and controls had no physical or psychological pathologies. The two groups were not different on the physical and psychological measures. Analyses of the interview data, however, indicated that all the syncope sufferers belonged to a cohesive and exclusive social network. Social psychological circumstances rather than individual psychopathology were noted to be primarily responsible for the spread and maintenance of the mass hysterical influence. Intervention consisted of health education, authoritative reassurance and back-up support. Follow-up assessment after three and 12 months indicated no further syncope episodes.

Adolescent↗

PubMed1996

Sonographically guided hydrostatic reduction of childhood intussusception using Hartmann's solution.

OBJECTIVE: Currently, the standard methods for therapeutic reduction of intussusception in children involve considerable ionizing radiation. This study tested the effectiveness of sonographically guided hydrostatic reduction of intussusception using Hartmann's solution, a fluid with near-physiologic composition. SUBJECTS AND METHODS: Between March 1, 1994, and January 31, 1996, all children clinically suspected of having intussusception were evaluated by sonography. Those with positive findings on sonography were entered into the study and underwent confirmatory sonographically guided meglumine diatrizoate enema. During continuous sonographic monitoring, we used Hartmann's solution for attempted reduction of intussusception. Criteria for successful reduction were disappearance of the intussusceptum and passage of fluid through the ileocecal valve. Another sonographically guided meglumine diatrizoate enema was used to confirm successful reduction. RESULTS: We detected 25 consecutive intussusceptions in 22 patients. The patients were 12 girls and 10 boys, with a mean age of 14 months (range, 1-72 months). Sonograms revealed in all patients doughnut or pseudokidney signs or both. The sites of intussusception were the transverse colon (17 of 25), hepatic flexure (4 of 25), ascending colon (2 of 25), splenic flexure (1 of 25), and descending colon (1 of 25). Other findings were dilated fluid-filled small bowel (11 of 25) and free intraperitoneal fluid (9 of 25). The success rate of our sonographically guided attempts at hydrostatic reduction was 76% (19 of 25). Success was proven by meglumine diatrizoate enema in all 19 patients. The mean time of the reduction procedure was 18 min (range, 2-45 min). No complications occurred. All six patients in whom hydrostatic reduction was unsuccessful underwent surgery. Five of these patients had ileoileocolic intussusceptions. On sonography, when surrounded by fluid, ileoileocolic intussusceptions had a typically complex, fronded appearance. The remaining patient in whom hydrostatic reduction was unsuccessful had ileocolic intussusception. Of six ileoileocolic intussusceptions, one was hydrostatically reduced and a second was converted into an ileoileal intussusception before requiring surgery. The other four intussusceptions were surgically treated. CONCLUSION: Our data suggest that sonographically guided hydrostatic reduction with Hartmann's solution can be used to treat ileocolic intussusception and to diagnose ileoileocolic intussusception.

Catheterization↗

PubMed1996

Existence of iodine deficiency in Hong Kong--a coastal city in southern China.

OBJECTIVE: Iodine deficiency is a serious public health problem worldwide which is associated with mental retardation and cretinism. In view of a high incidence of transient neonatal hypothyroidism and a relatively high mean cord blood thyrotropin (TSH) concentration, a pilot study was carried out to analyse the urine iodine excretion in Hong Kong, a coastal city in the southern part of China. DESIGN: Early morning urine was collected from healthy volunteers including children (n = 104), adults (n = 112) and elderly subjects (n = 349). A semi-quantitative questionnaire survey on the pattern of food intake was conducted in the adults and elderly. RESULTS: 45.3% of the children, 51.7% of the adults and 55.3% of the elderly had urine iodine concentration below the criteria for iodine sufficiency (< 0.79 mumol/l). Iodine content in the drinking water and salt was low. A dietary survey revealed that seafood was not commonly consumed. 50-80% of the subjects never consumed high-iodine containing food such as seaweed, kelp or laver, and only 50% consumed seawater fish daily. CONCLUSION: We confirmed that although Hong Kong is a non-goitrous area, iodine insufficiency exists. It is unsafe to assume that iodine deficiency does not exist in coastal urban areas.

Adolescent↗

PubMed1995

Growth hormone treatment of short Chinese children with beta-thalassaemia major without GH deficiency.

OBJECTIVE: Despite regular transfusion and desferrioxamine treatment, growth failure is commonly seen in adolescent children with beta-thalassaemia major. The growth failure has been thought to be due to GH resistance rather than GH deficiency. We investigated the effect of GH on short non-GH deficient children with beta-thalassaemia. DESIGN: Recombinant human GH was given in a dose of 0.14 IU/kg/day subcutaneously in an open study. PATIENTS: Fifteen prepubertal Chinese children with beta-thalassaemia major (ranging from 7.16 to 14.7 years in age) with height -1.5 SD or more below the population mean for age and a growth velocity of less than 5 cm/year were treated with growth hormone for one year. All children had peak GH response > 15mlU/l to insulin induced hypoglycaemia and normal thyroid function and adrenal reserve. MEASUREMENTS: Anthropometric measurements were performed every 3 months. Morning urine was tested twice weekly for glycosuria. Blood count, renal and liver function tests, fasting blood glucose, IGF-I and fructosamine levels were assessed at entry and every 3 months during treatment. Fasting insulin was measured before and after 3 and 12 months of GH treatment. Skeletal maturity was assessed before and after one year of treatment. RESULTS: Treatment was stopped in two children after 6 months because of poor growth response and noncompliance with treatment and in one child at 9 months because of bone marrow transplantation. In the 13 children, the growth velocity increased from 3.6 +/- 0.7 cm/year to 8 +/- 1.2 cm/year after one year of GH treatment (P < 0.001). IGF-I was low before treatment (10.1 +/- 2.7 nmol/l), rising significantly to 15.8 +/- 4.8, 18.4 +/- 4.6, 19.3 +/- 6.4 and 21.9 +/- 7.5 nmol/l at 3, 6, 9 and 12 months of treatment (P < 0.005). The mean pretreatment bone age in the 13 children was 9.58 +/- 1.41 years and increased to 10.53 +/- 1.43 years after one year of treatment (delta BA/CA 0.95 +/- 0.3 years). None of the patients developed glycosuria or hypertension. There was no significant change in blood count, renal and liver function, thyroid function, fasting blood glucose or insulin concentrations during treatment. CONCLUSION: Growth failure in these children with normal GH reserve and low serum IGF-I concentrations would suggest GH insensitivity. Supraphysiological doses of exogenous GH can cause a significant increase in serum IGF-I levels and a significant improvement in short-term growth of short children with beta-thalassaemia major.

Adolescent↗

PubMed1995

A cross-sectional study of growth, puberty and endocrine function in patients with thalassaemia major in Hong Kong.

METHODOLOGY: A cross-sectional study of growth, puberty and endocrine function was performed on 35 girls and 33 boys with thalassaemia major. RESULTS: Despite regular transfusion and chelation therapy, 75% of the girls and 62% of the boys over the age of 12 years were below the third percentile for height. Hypogonadotropic hypogonadism was found in a similar percentage of patients. Moderate to marked zinc deficiency secondary to chelation therapy was considered unlikely because normal serum zinc levels were found in all but three of our patients, but we could not exclude the possibility of a marginal status of zinc nutrition causing growth failure. Growth hormone deficiency and diabetes mellitus were sometimes encountered but hypothyroidism, hypoparathyroidism and adrenal insufficiency were rare among our patients. Most of the patients with growth failure had normal growth hormone (GH) response to insulin induced hypoglycaemia. The serum insulin-like growth factor-1 (IGF-1) levels were low in our patients and no significant difference in the serum IGF-1 levels was found between prepubertal children with or without growth failure (0.4 +/- 0.1 mU/mL vs 0.37 +/- 0.11 mU/mL, P = 0.39). Similarly, no difference in the serum IGF-1 levels was found between pubertal children with or without growth failure (0.48 +/- 0.2 U/mL vs 0.56 +/- 0.14 U/mL, P = 0.26). CONCLUSIONS: Delayed sexual maturation and a possible defect in growth unrelated to the GH-IGF-1 axis may be responsible for the growth failure in adolescent children with thalassaemia major.

Adolescent↗

PubMed1995

Incomplete catch-up growth in low birthweight Chinese infants in Hong Kong.

OBJECTIVE: To describe the early catch-up growth in length in Chinese low birthweight (< 2500 g) infants. METHODOLOGY: The infants (n = 181) were delivered between 1988 and 1993 and followed up at Queen Mary and Tsan Yuk Hospitals, Hong Kong. One third had a birthweight below -2SDS, most of whom were term or close-to-term babies small-for-gestational-age (SGA). The remaining babies were appropriate-for-gestational-age (AGA) in birthweight, but frequently born prematurely. RESULTS: The SGA group did not show a catch-up growth in height comparable to that reported on other recent studies, as 33-35% of the patients were still short at 6 and 12 months (7-12% for the AGA group). When comparing the postnatal mean growth curve of the SGA group with the mean curve of the AGA group there was little sign of catch-up growth. CONCLUSIONS: The results showed that Hong Kong SGA infants have an incomplete catch-up growth and for successful intervention the causative mechanisms have to be identified.

Body Height↗

PubMed1995

Invasive Haemophilus influenzae type b infections in children hospitalized in Hong Kong, 1986-1990. Hong Kong Hib Study Group.

A 5-year territory-wide retrospective survey of invasive Haemophilus influenzae type b diseases was conducted in Hong Kong. Between 1986 and 1990, 57 cases (28 male) were recorded in children less than 12 years old (37 cases of meningitis, 9 of septicaemia and 11 of bacteraemic pneumonia). The annual incidence for children less than 5 years old was 2.7 per 10(5) (95% confidence interval (CI) 2.0-3.5). Of the 57 cases, 39 were Chinese and 18 non-Chinese (7 Vietnamese refugees, 6 Caucasians, 5 others). The annual incidence in Vietnamese refugees less than 5 years old was 42.7 per 10(5) (95% CI 17.2-87.9), giving a relative risk of 18.5 (95% CI 8.3-41.0). Chinese patients (68%) were under-represented as Chinese accounted for at least 94% of the population. Moreover, 14 of the 39 Chinese patients had pre-existing medical problems, compared with only 1 of the 18 non-Chinese patients patients had pre-existing medical problems, compared with only 1 of the 18 non-Chinese patients (p = 0.022).

Child↗

PubMed1994

Familial testotoxicosis in a Chinese family.

We report two cases of 'familial testotoxicosis' in a family of Southern Chinese descent. The proband, an 8-year 4-month-old boy and his 35-year-old father both presented with early sexual development. In both cases the testicular volume was only 6 ml despite fully developed secondary sexual characteristics. Both patients had adult testosterone concentrations but a suppressed gonadotrophin response to gonadotrophin-releasing hormone. The suppressed gonadotrophin response to gonadotrophin-releasing hormone in the father suggests that autonomous gonadal production of sex steroid by the testes can persist well into adult life in some patients with familial testotoxicosis.

Adult↗

PubMed1994

Variant of the Triple A syndrome.

The Triple A syndrome is a rare condition comprising achalasia, alacrima and adrenocorticotrophic hormone (ACTH) insensitivity. A 12 year old Chinese girl with a variant of this syndrome (achalasia and alacrima), presenting with failure to thrive, is reported. Typical appearances of achalasia on barium swallow subsequently led to the correct diagnosis. The radiologist may be the first to recognize this syndrome and hence help anticipate its potentially life-threatening sequelae.

Adrenocorticotropic Hormone↗

PubMed1994

Screening test for growth hormone deficiency: usefulness of L-dopa-propranolol provocative test.

This is a retrospective review of 185 short children who were tested for growth hormone (GH) secretion using the L-dopa-propranolol provocative test. One hundred and thirty-three children were deemed to have passed the screening test when a GH concentration of greater than 15 miu/L was elicited after stimulation. Fifty-two failed the screening test, of which 33 were diagnosed as having growth hormone deficiency (GHD) when they had inadequate growth hormone response to insulin-induced hypoglycaemia. The other 19 were low-responders since they showed adequate GH response to insulin tolerance test (ITT). The low-responder rate to L-dopa-propranolol provocative test among short children who are not GH deficient was 12.5%. The low cost of L-dopa and propranolol, the simplicity and safety of the test, and the acceptable rate of low-responders make the test an effective screening test for GHD.

Adolescent↗

PubMed1994

Undetectable levels of serum FSH immunoactivity and bioactivity in girls with sexual precocity due to ovarian cysts.

Clinical presentation and endocrine investigations in five girls with precocious sexual development due to ovarian cysts are presented. These girls had pubertal oestradiol and suppressed gonadotrophin responsiveness to LHRH stimulation. FSH bioactivity as measured by the rat aromatase assay was undetectable in basal and LHRH-stimulated serum samples but our results cannot exclude the possibility of the presence of a species-specific follicle stimulating factor in these patients. IM injection of depot medroxyprogesterone acetate controlled pubertal development in two children.

Child↗

PubMed1993

Case report: lingual thyroid, a cause of neonatal stridor.

Stridor implies partial airway obstruction, resulting from intrinsic or extrinsic abnormalities of the upper respiratory tract. In a neonate whose airway is small, soft and easily occluded this may be potentially life threatening. Its immediate diagnosis with prompt therapy is a rewarding challenge. When stridor occurs in a neonate with congenital hypothyroidism, surgically amenable cause of obstruction due to an ectopic thyroid or thyroglossal cyst has to be seriously considered. We report a case of neonatal stridor caused by a lingual thyroid, and discuss the imaging approach.

Congenital Hypothyroidism↗

PubMed1992

Defective B-cell and regulatory T-cell function in Wiskott-Aldrich syndrome.

We report two Chinese boys with Wiskott-Aldrich syndrome presenting with gastro-intestinal bleeding, eczema and recurrent infection. They had thrombocytopenia and the mean platelet volume was small. Serum IgG and IgA were elevated and lymphocyte proliferation in response to phytohaemagglutinin, concanavalin A and pokeweed mitogen was defective. Despite documented herpes simplex virus type 1 and cytomegalovirus infection in one patient, he did not mount any humoral response. The generation of antibody-secreting cells in response to pokeweed mitogen was markedly defective in a plaque-forming cell assay. Both patients' regulatory T-cell and B-cell functions were defective in this assay. The genetic defect in Wiskott-Aldrich syndrome therefore affects T-cells, B-cells and platelets.

Antibody Formation↗

PubMed1992

Thyrotrophin-blocking antibodies in congenital hypothyroidism.

The role of transplacental transfer of maternal thyrotrophin (TSH)-blocking antibodies causing congenital hypothyroidism in Southern Chinese children was examined in this study. Twenty-two mothers of 24 patients with congenital hypothyroidism were studied 3-5 years after delivery. None of them had thyroid dysfunction at delivery or at the time of study. None had antithyroglobulin or antimicrosomal antibody. Only one mother was found to have TSH-binding inhibitory immunoglobulin (TBII), and her child had agenesis of the thyroid. This women had Graves disease in remission for 2 years before delivery. None had TSH-stimulated cAMP response inhibitory immunoglobulin (TSII). Ten of the 24 congenital hypothyroid children had transient neonatal hypothyroidism, seven had agenesis of the thyroid, six had dyshormonogenesis and one had a sublingual thyroid. As none of the mothers who had children with transient neonatal hypothyroidism had blocking antibodies at the time of study, the aetiology of the transient neonatal hypothyroidism remains unclear. These data suggest that maternal TSH-blocking antibodies do not play a role in most cases of sporadic congenital hypothyroidism.

Antibodies↗

PubMed1992

Immunodeficiency in methylmalonic acidaemia.

Three Chinese infants with methylmalonic acidaemia were described. They presented in the neonatal period with recurrent episodes of poor feeding, lethargy, apnoea and severe acidosis. The diagnosis was established by increased methylmalonic acid concentration in the plasma and/or urine. Pancytopenia was a prominent feature in all three patients. Only patient three had assessment of lymphocyte subsets and it showed diminished population of B-lymphocytes and a reversed CD4/CD8 ratio. All three patients were unresponsive to vitamin B12. They experienced severe infections including Gram-negative septicaemia, candidiasis and Pneumocystis carinii pneumonia which caused their deaths. Patients with this disease should be regarded as having severe immunodeficiency, and in addition to optimal metabolic control, they should be treated aggressively for any suspected infective episodes.

Amino Acid Metabolism, Inborn Errors↗

PubMed1992

Serum osteocalcin in normal and short Chinese children.

Serum osteocalcin was measured by radioimmunoassay in 200 normal children and adolescents, and seven growth hormone (GH) deficient and seven non-growth hormone deficient (NGHD) short children. There was a sex- and age-dependent change in the serum osteocalcin concentrations in normal children and adolescents with a pattern similar to the childhood height velocity curves. The serum osteocalcin concentration was in the low normal range in most patients with GH deficiency and NGHD short stature. GH therapy significantly increased the growth velocity in both groups of short children. GH treatment resulted in a significant rise in serum osteocalcin concentrations after 6 and 12 months in NGHD children but a more variable change was observed in GH-deficient children. Although osteocalcin levels may give some biochemical indication of growth, these measurements should be used together with auxological and other biochemical measurements to assess growth reliably.

Adolescent↗