Biomedical subjects
A Khalil
Publications and source records attributed to A Khalil.
Acute arsenic toxicity--an opaque poison.
We report a patient with fatal acute arsenic poisoning presenting as vomiting and diarrhea with the finding of intra-abdominal radiopacities on radiographs. These represent the classic features of acute arsenic toxicity and are detailed here as a reminder to others facing a similar puzzling patient with this potentially treatable poisoning.
Neonatal suppurative parotitis with facial palsy.
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Meningococcal meningitis. Clinical observations during an epidemic.
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Genetically determined hypercholesterolemia in a rhesus monkey family due to a deficiency of the LDL receptor.
A family of rhesus monkeys comprising a sire, a dam, and four male offspring were fed a cholesterol-free Purina Chow diet for several months. The sire, 431-J, and two of the offspring, B-8204 and B-8806, had persistent plasma cholesterol levels in the range of 100-130 mg/dl, whereas the dam, 766-I, and the two other offspring, B-1000 and B-7643, exhibited a marked hypercholesterolemia in the 250-300 mg/dl range associated with an elevation of plasma LDL and apoB. When fed for 12 weeks a diet containing 12.5% lard and 0.25% cholesterol, sire, dam, B-1000 and B-7643 exhibited a marked hypercholesterolemia (500-800 mg/dl range), whereas B-8204 and B-8806 developed only a modest hypercholesterolemia (200-250 mg/dl). All animals were Lp[a]+. Skin fibroblasts from each animal and from control cells were grown in 10% fetal calf serum, transferred to 10% lipoprotein-deficient serum for 48 hr, and then incubated at 4 degrees C or 37 degrees C with 125I-labeled Lp[a]-free LDL. The fibroblasts from dam and offspring B-1000 and B-7643 bound and internalized 125I-labeled LDL less efficiently than control cells. Mathematical analyses of the 4 degrees C binding data indicated that there were no significant differences in LDL binding affinity between test and control cells suggesting that cells from the animals with a spontaneous hypercholesterolemia had a decreased number of LDL receptors. This conclusion was supported by the results of ligand and immunoblot analyses carried out on cell lysates separated by gradient gel electrophoresis. We conclude that a genetically determined LDL receptor deficiency was responsible, in part, for the spontaneous hypercholesterolemia observed in three out of the six family members and that this deficiency accounted for the hyperresponsiveness to a dietary fat and cholesterol challenge by the dam and the two offspring, B-1000 and B-7643. The hyperresponsiveness noted in the sire that had no evidence for LDL-receptor deficiency illustrates that factors other than the LDL receptor were responsible for the hypercholesterolemia attending the fat challenge.
Hypertrophic osteoarthropathy in pulmonary tuberculosis.
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Antigenic relatedness between human lecithin-cholesterol acyltransferase and phospholipases of the A2 family.
A monoclonal antibody, B10, generated against pure human lecithin-cholesterol acyltransferase (EC 2.3.1.43) caused the inhibition of the esterolytic and cholesterol esterifying activities of the enzyme. This antibody also reacted with a number of pancreatic and snake venom phospholipases A2 species but not phospholipase A1. A concentration-dependent inhibition of phospholipase A2 was also seen in the presence of B10. Treatment of lecithin-cholesterol acyltransferase or B10-reacting phospholipases with phenacyl bromide, a reagent known to interact with the active site of phospholipase A2, inhibited both their esterolytic activity and their capacity to bind to B10. A dimeric phospholipase A2 species with a known occluded active site did not cross-react with B10. Thus, lecithin-cholesterol acyltransferase and some enzymes of the phospholipase A2 family share a common antigenic determinant which is probably located near or at their esterolytic active site.
Affinity of nonhomologous amphiphilic peptides toward a monoclonal antibody raised against apolipoprotein A-I.
Monoclonal antibodies against human apolipoprotein A-I (apoA-I) were generated by the hybridoma technique. Clone G-10 was selected on the basis of its highest titer. The affinity of this antibody toward a series of synthetic peptides differing in length, amino acid composition, and amphiphilicity was tested by using both the indirect and the competitive enzyme-linked immunosorbent techniques (ELISA). From these measurements we calculated dissociation constants of the complexes of the antibody with apoA-I bound to the surface of the microtiter plate, apoA-I in solution, and any of the several peptides in solution. The dissociation constant (Kd) of the immobilized apoA-I/anti-apoA-I-complex, Kd = 2 x 10(-9) M, was significantly lower than that of the complex resulting from the interaction between anti-apoA-I and either apoA-I in solution or any of the several amphiphilic helical peptides in solution. Peptides devoid of amphiphilic secondary structure were inert. These data are consistent with the proposal that monoclonal G-10 recognizes in antigenic peptides an alpha-helical secondary structure of defined hydrophilic-lipophilic balance and comparatively less the specific amino acid side chains. We propose that the highest contribution to the free energy of binding (8 Kcal/mole) is derived from the docking of the helix to the antibody. It follows that in probing the specificity of a monoclonal antibody the conformation and the physical environment of the interacting antigen must be taken into account.
Hepatic angiosarcoma among Egyptian farmers exposed to pesticides.
A greatly increased incidence of hepatic angiosarcoma (H.A.S.) among Egyptian farmers involved in pest-control spraying operations attracted our attention. Fourteen patients were diagnosed at Ain Shams University Hospital between the years 1980-1984 as having H.A.S. Eleven were males and 3 females with an average age of 49 years, and a male:female ratio of 3.8:1. Eleven patients reside in Lower Egypt and 3 in Upper Egypt. Ten out of the 14 patients had a definite history of a direct chronic recurrent exposure to agricultural pesticides of variable chemical nature, throughout the year. The period of exposure ranged from 11-20 years with an average of 14 years. The other 4 patients had no history of exposure to any of the known carcinogenic factors. This significant increase in angiosarcoma among farmers involved in pesticide spraying suggests that agricultural pesticides might play a role in the genesis of H.A.S. in Egypt.
Prolactinoma and adrenal androgens.
Theories about the relationship between hyperprolactinemia and hyperandrogenism are conflicting. Several reports assert that prolactin affects the delta 5 and delta 4 pathways through its effect on the activity of 3beta-hydroxysteroid dehydrogenase (3beta-OHSD). We measured delta 5 and delta 4 steroids, prolactin and cortisol in 18 amenorrheic, hyperprolactinemic women before and after resection of prolactinomas. Similar determinations of delta 5: delta 4 steroids were made in a control group of five women. The ratios of individual delta 5: delta 4 steroids were also analyzed. Our results support a modification of delta 5, delta 4 pathways through an effect on the rate-limiting enzyme 3 beta-OHSD. In hyperprolactinemic women the differences between the preoperative and postoperative steroid levels were significant. Further, since the androgens decreased irrespective of the prolactin following surgery, there probably is a factor other than ACTH and prolactin modulating the adrenal androgens.
Sexual precocity in primary hypothyroidism.
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Hepatic histochemistry and electron microscopy of hamsters infected with S. mansoni and treated with praziquantel therapy.
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Pituitary thyrotroph hyperplasia mimicking prolactin-secreting adenoma.
A 32-year-old woman with persistent postpartum galactorrhea, hyperprolactinemia and a sellar configuration compatible with pituitary adenoma underwent transsphenoidal surgery. Mild hyperthyroidism had been suspected clinically preoperatively and thyroxine plus cortisol therapy was given. Morphological features of pituitary thyrotroph hyperplasia were present as shown by light microscopy, immunoperoxidase staining and electron microscopy. The thyrotroph hyperplasia was secondary to primary hypothyroidism as demonstrated by the TSH response to TRH stimulation and subsequent suppression with thyroid hormone treatment. Although prolonged severe hypothyroidism has been reported to cause pituitary enlargement, this is the first case of thyrotroph hyperplasia with detailed morphologic study of the surgically-removed adenohypophysial tissue. The presentation of this patient calls attention to the possibility of mistaking pituitary enlargement due to primary hypothyroidism for a prolactinoma.
Spontaneous secretion of thyroid autoantibodies by cultured peripheral blood lymphocytes from patients with Hashimoto's thyroiditis detected by micro-ELISA techniques.
The spontaneous in vitro production of anti-thyroglobulin (aTg) and anti-microsomal (aM) antibodies by mononuclear cells (MNC) from patients with Hashimoto's thyroiditis (HT) was analysed by an ELISA detection system. MNC from 35 HT patients spontaneously produced detectable levels of both autoantibodies in vitro (i.e., without mitogenic or antigenic stimulation). aTg was quantified using a reference aTg IgG standard and ranged from 55 to 9,000 ng aTg. Specificity of aTg by ELISA was assessed using heterologous Tg antigen (Ag). Microsomal Ag obtained by gel filtration was far less contaminated with Tg than the ultracentrifugation pellet. Specificity of aM ELISA was assessed using insulinoma membrane as unrelated Ag and by blocking aM detection only with microsomal Ag. aM levels in the 35 supernatants ranged from 0.1 to 1.12 OD. A direct correlation was found between aM serum titres detected by haemagglutination and in vitro aM spontaneous production, but not for aTg. This lack of correlation for aTg might have biological relevance. Tg restimulation in vitro enhanced aTg production in only four out of 18 cases, of which only one was significant. This system provides a tool for studies of the immunoregulation of thyroid autoantibody formation in vitro.
Ultrasonography as a new important potential in improving family planning service.
Population control in developing countries is a very significant and pressing problem. Therefore improving family planning service is mandatory. Four gynaecologists from four major hospitals in Egypt express their experiences and their uniform agreement about the improvement in family planning services through ultrasonography in both free hospital and private patients.
The effect of praziquantel therapy on the histopathological and parasitological aspects of experimental schistosomiasis mansoni.
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[Pericarditis and chronic myelocytic leukemia (author's transl)].
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