The chemical composition of gallstones: its relevance to surgeons in Southeast Asia.

This paper describes the methods in the study of the chemical composition of gallstones and the application of this knowledge to the practising surgeon in Southeast Asia. There are three types of stone in this part of the world. Inspecting with the naked eye, the surgeon is usually able to recognize accurately the stone type--cholesterol, black pigment and brown pigment. The stone type together with the clinicopathological and radiological findings enable the surgeon to make a confident diagnosis of either the Western-type (cholesterol and black pigment) or Asiatic-type (brown pigment) gallstone disease in each patient, and based on this, a rational approach in the management of the patient can be instituted. In a personal series of 484 cases, cholesterol stones formed 46% of the cases, black pigment stones 30.5% and brown stones 13%; and cholesterosis and acalculous cholecystitis constituted the remaining 10.5%. In rapidly developing Singapore, Western-type cholesterol stones now predominate while brown stones appear to be decreasing. In patients with small bile duct stones of any stone type, endoscopic extraction followed by laparoscopic cholecystectomy appears to be the procedure of choice. Large bile duct stones require open surgery. In patients with grossly dilated bile ducts containing brown stones, biliary enteric bypass is performed to reduce biliary stasis, cholangitis and recurrent stone formation.

Effect of decalcification on bone mineral content and bending strength of feline femur.

The relationships between bone mineral content (BMC), bone calcium, and bone strength were studied in fractionally demineralized feline femurs. In 44 pairs of cat femurs, the right bones were decalcified in ethylene diaminetetra acetic acid (EDTA) to 20%, 40%, 60%, 80%, and 100% of the mineral content of the intact left bone (= control). The bones were then loaded to failure, and maximum strength values were recorded. The data were then used to calculate the percentage strength of the right relative to the left femurs. A correlation coefficient (r) of 0.970 was found between the percentage decalcification and percentage bending strength. A direct relationship (r = 0.876) was also observed between the total calcium extracted and total loss in BMC. The EDTA solutions were spot checked for protein content to determine if the organic matrices had been altered by demineralization. Protein was never detected. Nor did the demineralized tissues display histologic evidence of gross microscopic damage. This study has shown that in cat femurs, 20% decalcification led to about 35% loss in bending strength, and 60% decalcification caused 75% loss in strength. These values are significant as they highlight the importance of calcium to the strength of osteopenic bone.

Serum and red blood cell magnesium, copper, and zinc content in G6PD deficiency.

Sixty-nine G6PD-deficient and 67 normal non-deficient Chinese adult males were investigated for blood hemoglobin concentration and for serum and red cell content of magnesium, copper, and zinc. There was no significant difference in blood hemoglobin content. Both the serum magnesium and copper content were found to be significantly lower in the G6PD-deficient subjects compared to that in the non-deficient control. Serum zinc content and red cell content of all the three metals were not significantly altered in G6PD deficiency.

Lack of correlation of selenium level in human semen with sperm count/motility.

Considering the importance of selenium (Se) in male fertility, its concentration was measured in 211 semen samples from 211 normozoospermic, oligozoospermic, asthenozoospermic, and azoospermic men using the hydride generation atomic absorption spectrophotometry. No significant correlation of any kind existed between Se level in the seminal plasma and sperm count or motility. In view of the known poor correlation of these two frequently used semen parameters with the incidence of pregnancy, the assessment of the fertilizing potential of normozoospermic ejaculates with low Se levels is warranted.

Correlation of contraceptive activity of norethisterone and levonorgestrel esters with VR(w) values and hydrolysis rates.

The relationships between contraceptive activity, hydrophobic character and alkaline hydrolysis rates were studied in three homologous series of norethisterone and levonorgestrel esters. Hydrophobic character was expressed by the high-performance liquid chromatographic retention term, VR(w) or retention volume at 100% aqueous mobile phase. A parabolic and bilinear relationship was shown between log VR(w) and log biological response. No correlation between second-order alkaline hydrolysis rates, k2, measured in 70% (v/v) aqueous dioxan and contraceptive activity was established.

Studies on long-acting aryl carboxylic acid esters of testosterone.

A series of aryl carboxylic acid esters of testosterone have been synthesized as possible agents for long-acting steroid therapy. The solubilities, partition coefficients and hydrolysis rate constants of the compounds have been determined. The results show that the partition coefficients increase with increasing chain length and are in keeping with calculated values. The hydrolysis rates decrease with increasing chain length except for the first member of the series (benzoate ester) which exhibits the slowest rate, possibly due to the hydrolytic attack being hindered by steric and electronic effects.

Selenium status in pregnancy: studies in amniotic fluid from normal pregnant women.

Selenium concentrations were determined in amniotic fluid samples obtained from 111 healthy normal pregnant women (median age, 27.5 years) between 12 and 42 weeks of gestation using hydride generation technique coupled with atomic absorption spectroscopy. There was a gradual decrease in the amniotic fluid selenium concentration with the progress of pregnancy. The negative correlation between the gestational age and amniotic fluid selenium concentration was highly significant (p less than 0.001). The implications of these findings in normal pregnancy are discussed.

Amniotic fluid selenium status in pre-eclampsia.

Selenium levels were measured in amniotic fluid samples obtained from 60 normal pregnant and 40 pre-eclamptic women closely matched for age and gestation using the hydride generation technique coupled with atomic absorption spectroscopy. The mean +/- SD levels in the normal and pre-eclamptic groups were 6.8 +/- 3.7 and 6.7 +/- 2.2 ng/ml, respectively. The difference in the values of amniotic fluid selenium between these two groups of patients was not statistically significant (p greater than 0.5).

Human follicular fluid levels of calcium, copper and zinc.

Human follicular fluid was collected under laparoscopic vision from 33 follicles in patients stimulated with clomiphene-human menopausal gonadotrophin in an IVF programme. Thirty-one oocytes were obtained from 26 follicles from which clear follicular fluid was obtained, and 16 oocytes fertilized and cleaved. The follicular fluid was analysed for calcium, copper and zinc using atomic absorption spectroscopy. The mean levels of calcium, copper and zinc were 86.9 +/- 11.6, 1.16 +/- 0.29, and 0.72 +/- 0.12 micrograms/ml, respectively. Their levels were not significantly different in the follicular fluid collected from follicles of different sizes, with or without oocyte, and follicles with oocytes that were fertilized and were unable to be fertilized. Therefore, the concentrations of these elements do not seem to reflect oocyte status or maturity.

Norethisterone and levonorgestrel esters: a novel synthetic method.

Aliphatic, alicyclic and arylcarboxylic esters of norethisterone and levonorgestrel were prepared in a one-step synthesis and in near-quantitative yield using trifluoroacetic anhydride.

Hepatotoxicity of dimethylformamide and dimethylsulfoxide at and above the levels used in some aflatoxin studies.

Albino rats were each treated with a single intraperitoneal injection of dimethylformamide (DMF) or dimethysulfoxide (DMSO). The doses of DMF administered were 0.6, 0.9, and 1.2 ml. per kg. and those of DMSO were 1.2, 2.4, 3.6, and 4.8 ml. per kg. The animals were sacrificed at 24, 48, 72, and 120 hours following administration of each dose. The liver was investigated in all cases. Treatment with DMF at 0.6 ml. per kg. indicated some histologic lesions of the liver which became well defined at 0.9 and 1.2 ml. per kg. causing severe central phlebitis with centrilobular coagulative necrosis of the cells associated with a heavy inflammatory infiltrate. Maximal liver lesions occurred at 48 hours and started to regress after 72 hours. However, cellular atypism became a consistent finding after this inflammatory phase. DMSO-treated animals showed minimal histologic lesions of the liver at 1.2 and 2.4 ml. per kg. Higher doses caused fatty infiltration with a predominatly periportal distribution. It tended to produce its maximal effect in 12 hours which then regressed rapidly after 24 hours. The development of histologic lesions in the liver even at 0.6 ml. per kg. suggests that DMF is not a suitable solvent for aflatoxin studies, and hence the results obtained from such studies need cautious interpretation. DMSO appears to be an ideal alternative for toxicologic studies at a much higher dose level compared to DMF.