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Biomedical subjects

A K Thomas

Publications and source records attributed to A K Thomas.

At least 19 recordsLinked to original sources
PubMed1999

Disorders of maternal calcium metabolism implicated by abnormal calcium metabolism in the neonate.

Normal fetal and neonatal calcium homeostasis is dependent upon an adequate supply of calcium from maternal sources. Both maternal hypercalcemia and hypocalcemia can cause metabolic bone disease or disorders of calcium homeostasis in neonates. Maternal hypercalcemia can suppress fetal parathyroid function and cause neonatal hypocalcemia. Conversely, maternal hypocalcemia can stimulate fetal parathyroid tissue causing bone demineralization. We report two asymptomatic women, one with previously unrecognized hypoparathyroidism and the other with unrecognized familial benign hypercalcemia, who were diagnosed when their newborn infants presented with abnormalities of calcium metabolism. J.B. was born at 34 weeks' gestation with transient hyperbilirubinemia and thrombocytopenia. At 1 month of age he had severe bone demineralization, cortical irregularities, widening and cupping of the metaphyses, and lucent bands in the scapulae. The total serum calcium and phosphorus were normal with an ionized calcium of 5.4 mg/dL (4.6-5.4). His alkaline phosphatase, parathyroid hormone, and 1,25-dihydroxyvitamin D levels were all increased. P.B., mother of J.B., had no symptoms of hypocalcemia either prior to, or during this pregnancy. She had severe hypocalcemia and hyperphosphatemia, laboratory values typical of hypoparathyroidism. J.N. presented at 6 weeks of age with new onset of seizures and tetany secondary to severe hypocalcemia. The serum phosphorus, creatinine, alkaline phosphatase, and parathyroid hormone levels were normal. At 15 weeks of age his calcium was slightly elevated with a low fractional excretion of calcium. P.N., mother of J.N., had no symptoms of hypercalcemia either prior to, or during this pregnancy. Her serum calcium was 12.7 mg/dL and urine calcium was 66.5 mg/24 hr, with a low fractional excretion of calcium ranging from 0.0064 to 0.0073. P.N. has a brother who previously had parathyroid surgery. Both J.N. and P.N. meet the diagnostic criteria for familial benign hypercalcemia. These cases illustrate the important relationships between maternal serum calcium levels and neonatal calcium homeostasis. They emphasize the need to assess maternal calcium levels when infants are born with abnormal serum calcium levels or metabolic bone disease.

Adolescent↗
PubMed1997

In vivo and in vitro studies on the sonographical detection of Ascaris lumbricoides.

Intestinal ultrasound, a frequently applied diagnostic tool in industrialized nations, has recently also been introduced in tropical regions. This study attempts to describe the anatomical and sonographical features of Ascaris lumbricoides in the human intestine. In the course of a schistosomiasis morbidity study in Madagascar, 581 inhabitants of a rice-farming village on the high plateau of the island had their stools examined by means of a modified Kato-Katz thick smear technique (four slides per sample); 53% had eggs of Ascaris lumbricoides in their stools. Twenty-two individuals underwent intestinal ultrasound examination and, in six cases, Ascaris lumbricoides was visualized. All six patients showed eggs upon stool examination. At ultrasound, the parasite was seen as a large, curved echogenic strip (4-6 mm in diameter) with an inner, anechoic, longitudinal canal. The image resembled a winding highway, the central structure representing the pseudocoel of the parasite. Patients were treated with mebendazole. The excreted worms of one patient were scanned under water, showing the same characteristics as in vivo. We conclude that Ascaris lumbricoides has a characteristic sonographical appearance and should not be a confounding factor in studies using intestinal ultrasound.

Aged↗
PubMed1997

Evaluation of ultrasonographic staging systems for the assessment of Schistosoma mansoni induced hepatic involvement.

For the sonographic assessment and grading of hepatosplenic morbidity induced by Schistosoma mansoni infection, several quantitative and qualitative classification systems have been used. In an attempt to evaluate two staging systems, a study was performed as part of a schistosomiasis research and control programme in Richard Toll, Senegal. A total of 700 residents of the township N'diangué were parasitologically, clinically and sonographically examined in July 1993. Two ultrasound observers (M.D. and E.D.) applied the Cairo and the Managil classification (E.D. only) for the grading of periportal thickening of the liver. In spite of high prevalence and intensity of infection, severe hepatic morbidity was rare. According to the Cairo classification, there was a high percentage of subjects with grade I periportal thickening, with considerable inter-observer variability. In the Cairo classification, which is based on the diameter of peripheral portal vein branches, firm cut-offs are used, independent of body height. We show the relationship between body height and portal vein diameters and recommend the use of body height-dependent reference values to avoid falsely high percentages of periportal thickening, especially in children. To minimize inter-observer variability, a clarification of existing instructions for taking measurements for grading is suggested. These suggestions have been considered during the follow-up expert meeting on the Cairo classification in Niamey under the auspices of the World Health Organization in October 1996.

Adolescent↗
PubMed1997

Organometric investigations of the spleen and liver by ultrasound in Schistosoma mansoni endemic and nonendemic villages in Senegal.

With the intention of ultrasonographically assessing hepatosplenic morbidity in Schistosoma mansoni infection and of validating the grading system applied (Cairo classification), 191 subjects in a schistosomiasis endemic village and 247 controls from a nonendemic village in northern Senegal underwent sonographic examination of the liver and spleen. Measurements of the diameters of the peripheral periportal vein branches, the main portal vein stem, liver size (left lobe and right lobe), and spleen length in the endemic village were compared with those in the nonendemic village to evaluate the much discussed influence of S. mansoni infection on those variables. To subtract this presumed influence from reference values for the named variables, they are given as measured in the nonendemic village, stratified by body weight, enabling future investigators on schistosomiasis-induced morbidity to refer to these reference values. The 95th percentile regarding peripheral periportal vein branch diameter in the control groups was exceeded in 24% of the subjects in the endemic group. It was exceeded by 6% for the main portal vein stem diameter, 13% for the left liver lobe, 12% for the right liver lobe, and 14% for the spleen length. According to the Cairo classification, 97% of the endemic population and 81% of the controls had periportal thickening of the liver, mostly grade I. We conclude that 1) hepatic morbidity in the S. mansoni endemic area was low, despite strikingly high intensities of infection; 2) the Cairo classification in its present form overestimates periportal thickening, especially in the case of mild morbidity; and 3) body height-dependent reference values, obtained from endemic controls, must be applied for organometric parameters.

Adolescent↗
PubMed1996

The natural history of cold intolerance of the hand.

When cold intolerance occurs in the injured hand, it is persistent in the majority of cases (79 per cent). Statistically, there is a link between the development of cold intolerance and the incidence of early postoperative pain. Postoperative pain relief should be of high quality and may possibly prevent the onset of cold intolerance.

Cold Temperature↗
PubMed1996

Ultrasonography in a Senegalese community recently exposed to Schistosoma mansoni infection.

Inhabitants of Ndombo (n = 614), a village in an area recently infected with Schistosoma mansoni in Northern Senegal, were examined clinically, parasitologically, and ultrasonographically to investigate the presence and degree of S. mansoni-related hepatosplenic morbidity after a few years of exposure to schistosomal infection of regional canals. Despite previous praziquantel treatment of 56% of the inhabitants prior to our investigation, the prevalence of S. mansoni infection in 1993 was 90%, and 42% of the villagers excreted more than 1,000 eggs per gram of stool. Previously untreated individuals were found to have significantly higher egg counts than treated ones. Despite the high intensities of infection, ultrasonographically detected severe periportal thickening of the liver was infrequent. Grading according to body length-dependent normal values of cross-section diameter of peripheral portal vein branches of a European control group correlated with intensities of infection. Of the total group of patients, 30% (n = 182) had more severe thickening of portal vein branch diameters above the 97th percentile and 70% of these had a splenomegaly. The highest egg counts and the most frequent development of periportal thickening were found in 11-20 year-old individuals. Periportal thickening was less frequent in praziquantel-treated adolescents than in untreated ones. This suggests that early antischistosomal medication may be useful to limit schistosomiasis-induced hepatic morbidity especially in children, even though reinfection seems inevitable.

Adolescent↗
PubMed1995

Changing incidence and geographical distribution of malignant paediatric germ cell tumours in the West Midlands Health Authority region, 1957-92.

The West Midlands Regional Children's Tumour Research Group holds high-quality data from 1957 on all childhood cancers in the West Midlands Health Authority region. Since it has been reported that malignant germ cell tumours are increasing in incidence in the north-west of England, we undertook to examine rates in this region and to map the distribution of cases in order to assess any geographical changes in incidence rates. We identified a total of 102 malignant germ cell tumours (MGCTs) between 1957 and 1992. The average age-standardised rate was 1.6 per million per year in the period 1957-74 and 3.6 per million per year during 1975-92, a significant increase (P = 0.0004). Particular increases were noted in older children (10-14 years); P = 0.0002) and in yolk sac (endodermal sinus) tumours (P = 0.004). A small excess was also observed in Asian children when compared with other diagnoses. Geographical analysis showed particularly higher rates at health district level in the West Midlands conurbation as compared with the other areas in the period 1975-92. These factors suggest the possibility that industrial/urban or population effects may be implicated in the observed increase in childhood MGCT and we recommend these areas for further studies.

Adolescent↗
PubMed1991

Comparison of sequential cyproterone acetate/estrogen versus spironolactone/oral contraceptive in the treatment of hirsutism.

The effects of the antiandrogen drugs cyproterone acetate (CPA) and spironolactone on hair growth and androgen levels were compared in a randomized study of 48 hirsute women. Twenty six subjects completed 6 months of therapy with 100 mg/day CPA and 19 subjects completed 6 months of 100 mg/day spironolactone. All except 10 subjects received concomitant estrogen therapy. Measured objectively, total hair diameter fell by 17.1% with spironolactone (P less than 0.001), and by 16.8% with CPA (P less than 0.001). The diameter of the hair medulla fell by 17.8% with spironolactone (P less than 0.01), and by 31.7% with CPA (P less than 0.001). There was no difference between the drugs in their effect on hair diameter. Plasma testosterone levels also fell significantly with both drugs. As a subjective assessment of treatment efficacy, the frequency with which subjects performed cosmetic measures was recorded. This fell by 38% with spironolactone and by 44.7% with CPA (P less than 0.001 both drugs), and again there was no difference between the drugs. Side effects caused cessation of treatment in one subject taking CPA and two subjects taking spironolactone, and milder side effects were noted in two further subjects from each treatment group. We conclude that spironolactone and CPA, in the dosages used in this study, are effective and well tolerated agents for the treatment of hirsutism, and that neither drug demonstrates a particular advantage over the other.

Adult↗
PubMed1989

Induction of ovulation with subcutaneous pulsatile gonadotropin-releasing hormone: correlation with body weight and other parameters.

We treated 21 anovulatory infertile patients with subcutaneous pulsatile gonadotropin-releasing hormone (GnRH) administered via a syringe pump. Response to treatment was assessed by urinary estrogen excretion and ultrasound measurement of follicular growth. Ten patients ovulated and 8 subsequently conceived, for a total of 10 pregnancies. Human chorionic gonadotropin (hCG) was not administered routinely, but two patients required hCG to induce follicular rupture. The majority of the patients who conceived had a body mass index (BMI) of less than 21 and a luteinizing hormone (LH)/follicle-stimulating hormone ratio of less than 1. Conversely, those patients with either elevated BMI or LH or both generally failed to respond satisfactorily to this treatment. It is suggested that pulsatile GnRH is most likely to succeed in inducing ovulation if the BMI is less than 21 and the LH is normal, but is unlikely to be successful if there is both an elevated LH and a BMI of greater than 25. Between these two extremes, the response is variable and a therapeutic trial may be appropriate.

Anovulation↗
PubMed1983

Menstrual pattern and fertility after treatment for anovulatory infertility.

Sixty-four patients who had been treated for anovulatory infertility and subsequently conceived were reviewed. Information was obtained on subsequent menstrual pattern, contraception used, treatment required to achieve a further pregnancy and the interval to any such pregnancy. Almost half the group had regular cycles following delivery but 2 patients had a recurrence of post oral contraceptive amenorrhoea. Most patients conceived without treatment within 2 years of the initial pregnancy but 10 again required ovulation induction. It is concluded that there is no long-term irreversible suppression of hypothalamic function in this group of patients and, once a pregnancy has been achieved, the prognosis for future fertility without therapy is good.

Anovulation↗