Treatment of human IgG with cyanogen bromide in 0.05 M HCl under specified conditions resulted in the cleavage of about half of its methionyl peptide bonds. A major fragment of about 5S was isolated from the reaction mixture by gel filtration in quantitative yield. The CNBr fragment reacted fully with goat antiserum against human light chain, but its reaction with anti-heavy chain was markedly decreased. The treatment with CNBr caused a drastic decrease in the following biological activities of IgG: complement fixing, skin binding, reaction with antiglobulin factors, and reaction with specific anti-Gm(12) serum. On the other hand, the reaction with serum of anti-Gm(1) or anti-Gm(4) specificity was not impaired and antibody activity, namely antistreptolysin and isohemagglutinin, was retained after the treatment with CNBr. It is concluded that the CNBr cleaves preferentially the methionyl bonds in the Fc portion of IgG, and that the major fragment obtained, denoted F(ab'')(2), has still the combining properties of a divalent antibody. The possible therapeutic uses of F(ab'')(2) are discussed.

Antibody Formation↗

PubMedDate not supplied

Amplification of optical activity by crystallization in the presence of tailor-made additives. The "inversion rule".

Experiments are described in which enantiomerically pure dimers, trimers and oligomers, generated from non chiral monomers by crystallization and topochemical reaction in suitably designed chiral crystals, induce preferential crystallization of the parent monomer in the enatiomorphous chiral phase of opposite absolute configuration. (We coin the term "inversion rule" for this effect). A general mechanism of amplification of optical activity by crystallization is proposed on the basis of these results, involving selective adsorption of resolved impurities on the surface of chiral crystals of similar stereochemistry, resulting in a decrease of the growth rate of the affected enantiomer and consequent preferential crystallization of the antipode. The implications of this mechanism to the generation and amplification of chirality in a closed system are discussed.

Crystallization↗

PubMedDate not supplied

Effects of cyclic AMP and of 2-mercapto-1-(beta-4-pyridethyl)benzimidazole on composition of steroids secreted by a testicular tumour cell line.

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Animals↗

PubMedDate not supplied

Direct evidence for absence of beta-adrenergic receptors in rat cerebral vessels histochemical study with a fluorescent beta-blocker.

A fluorescent marker for beta-adrenergic receptor sites, 9-amino-acridin propranolol (9-AAP), was administered intravenously to rats. In contrast to other tissues which are known to contain beta-adrenergic receptors, 9-AAP fluorescence was not observed in the walls of the pial as well as parenchymal cerebral vessels. These negative findings strongly suggest that in the rat, beta-adrenergic receptors are not present in the cerebral vasculature. The role of the alpha-adrenergic receptors needs more study.

Animals↗

PubMedDate not supplied

Effect of interferon alpha IIb on the activity of sialyltransferase in testis homogenates of adult rats.

Interferon alpha IIb was injected to adult male rats at doses ranging from 10,000 to 200,000 units. Animals were dissected at intervals of 12 h, 24 h, and 5 days. The activity of the enzyme sialyltransferase in testis homogenates was estimated. In the majority of experiments enzyme activity decreased in comparison to controls.

Animals↗

PubMedDate not supplied

Early invasive pulmonary aspergillosis in a leukemia patient linked to aspergillus contaminated marijuana smoking.

46-year-old patient with acute myeloid leukemia (AML) whose disease manifested as fever, chills and dry cough is reported here. Despite broad antibiotic coverage he remained acutely ill with spiking fever, shaking chills, and hypoxemia. His initial chest radiograph was normal but chest computed tomography (CT) scan disclosed bilateral focal infiltrates. Hypoxemia and severe thrombocytopenia precluded invasive diagnostic procedures. A thorough epidemiological investigation revealed that before becoming acutely ill the patient smoked daily tobacco mixed with marijuana from a "hookah bottle". While waiting for tobacco and "hookah water" cultures, we started antifungal therapy. Resolution of fever and hypoxemia ensued after 72 hours. Tobacco cultures yielded heavy growth of Aspergillus species. We suggest that habitual smoking of Aspergillus-infested tobacco and marijuana caused airway colonization with Aspergillus. Leukemia rendered the patient immunocompromised, and allowed Aspergillus to infest the lung parenchyma with early occurrence of invasive pulmonary aspergillosis. Physicians should be aware of this potentially lethal complication of "hookah" and marijuana smoking in immunocompromised hosts.

Aspergillosis↗

PubMedDate not supplied

Familial band-shaped keratopathy.

A brother and sister out of a consanguinous family of four siblings are presented as prototypes of primary band-shaped keratopathy. The disease manifested sever progressive changes of secondary nature over two years of follow-up. Histology and treatment are described.

Child↗

PubMedDate not supplied

Flecked retina secondary to oxalate crystals from methoxyflurane anesthesia: clinical and experimental studies.

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Aged↗

PubMedDate not supplied

Sciatic pain: a diagnostic pitfall.

Neurological signs such as lower spinal cord lesions and/or femoral neuritis may be the presenting symptoms of a dissecting abdominal aortic aneurysm (AAA). We describe a patient in whom a severe sciatic pain was the presenting symptom of a non-dissecting AAA. The resection of the vascular mass resulted in dramatic relief of sciatic pain, thus indicating that the neurological impairment was caused by the non-dissecting aneurysm.

Aorta, Abdominal↗

PubMedDate not supplied

Separation of human semen on Percoll gradients: effect on percentage of motile and morphologically normal sperm and proportion of acrosome reacted sperm.

OBJECTIVES: To examine whether sperm motility and morphology correlate with ability to undergo the acrosome reaction in vitro. METHODS: Sixty-one seminal specimens were separated on a discontinuous Percoll gradient (70%, 40%). Percentages of motile and morphologically normal sperm, their motility grade, and percentages of acrosome-reacted sperm before and following acrosome reaction inducing treatment were estimated. RESULTS: Percentage of motile sperm from normozoospermic specimens increased from whole semen (47.6 +/- 5.6) to sediments (59.6 +/- 13.0). Motility grade exhibited a similar trend (2.1 +/- 0.5 and 3.6 +/- 0.5-scale of 1-4). Percentage of morphologically normal sperm increased from semen (27.3 +/- 10.9) to sediment (53.8 +/- 14.8). All differences were statistically significant, (P < 0.00). In abnormal semen the motility grade and percentage of morphologically normal sperm also increased from semen to sediment (1.9 +/- 0.4 to 3.2 +/- 0.8 and 17.7 +/- 7.8 to 37.1 +/- 15.4 respectively, (P < 0.001). Percentages of motile sperm were similar. In normozoospermic sediments, both non-treated or treated to induce the acrosome reaction, proportions of acrosome-reacted sperm were significantly higher than in semen (18.3 +/- 6.9% and 20.0 +/- 6.5% vs. 6.8 +/- 4.2% respectively, P < 0.001). A similar trend was obtained using abnormal aliquots; however, the acrosome-reacted sperm accounted for only 9.0 +/- 5.1% and 10.8 +/- 4.3% versus 5.4 +/- 2.8% (P < 0.025). CONCLUSIONS: Morphology and motility of sperm were correlated with the proportion of acrosome-reacted sperm.

Acrosome↗