'Magic' nucleus 42Si.

Nuclear shell structures--the distribution of the quantum states of individual protons and neutrons--provide one of our most important guides for understanding the stability of atomic nuclei. Nuclei with 'magic numbers' of protons and/or neutrons (corresponding to closed shells of strongly bound nucleons) are particularly stable. Whether the major shell closures and magic numbers change in very neutron-rich nuclei (potentially causing shape deformations) is a fundamental, and at present open, question. A unique opportunity to study these shell effects is offered by the 42Si nucleus, which has 28 neutrons--a magic number in stable nuclei--and 14 protons. This nucleus has a 12-neutron excess over the heaviest stable silicon nuclide, and has only one neutron fewer than the heaviest silicon nuclide observed so far. Here we report measurements of 42Si and two neighbouring nuclei using a technique involving one- and two-nucleon knockout from beams of exotic nuclei. We present strong evidence for a well-developed proton subshell closure at Z = 14 (14 protons), the near degeneracy of two different (s(1/2) and d(3/2)) proton orbits in the vicinity of 42Si, and a nearly spherical shape for 42Si.

Testicular gonadal stromal (Sertoli cell) tumor.

Eighty-one cases of testicular gonadal stromal tumor have been reported in the literature. An additional case is herein reported. The pathologic, immunohistologic, and histogenetic aspects are presented.

Mass spectrometry and stability of t-butyldimethylsilylethers of some estrogens and androstanes.

In addition to using radioimmunoassays for the determination of estrogens and other steroids, the possibility of using mass fragmentography for analysis was investigated. t-Butyldimethylsilyl chloride was selected as a reagent for derivatisation because it forms rather stable silylethers. In all the mass-spectra obrained from the steroid derivatives, one pronounced peak suitable for mass fragmentography was always present. Some of the spectra of the investigated estrogens, as well as testosterone, 3 alpha-hydroxy-5 alpha-androstan-17-one and 17 alpha-methyl-17 beta-hydroxy-5 alpha-androstan-3-one are discussed. The stability of various t-butyldimethylsilylethers and the rate of enolization of testosterone and progesterone in the presence of the silylation-agent under different conditions were established.

Marked concomittant elevations in serum creatine kinase and lactic dehydrogenase in a patient with bowel necrosis.

We report what we believe to be the first proven marked concomittant elevations in serum creatine kinase (CK) and lactic dehydrogenase (LD) in a patient with bowel necrosis. The necrosis was the result of infarction secondary to bowel strangulation. The serum from this patient showed elevation of total CK activity resulting from an abnormal amount of MM, MB, and BB isoenzymes with LD2, LD3, and LD5 yielding 18 per cent, 19 per cent, and 29 per cent, respectively, of the total LD activity.

Invasive pituitary oncocytoma.

A large invasive pituitary neoplasm, surgically resected by left frontotemporal craniotomy, and thought to represent "chromophobe" adenoma by light microscopy, exhibited ultrastructural features characteristic of oncocytoma. Electron microscopic and immunocytochemical studies showed that the tumor did not possess enhanced secretory activity. The indispensable role of electron microscopy in the identification of this rare neoplasm and especially in the classification of all pituitary tumors is emphasized.

Comparison of serum CA 19-9 and CEA levels in a population at high risk for colorectal cancer.

The sera of 563 patients who underwent colonoscopy were assayed for glycolipid antigen CA 19-9 and CEA. These patients represented a broad spectrum of clinical diseases ranging from advanced metastatic cancer of the colon, pancreas, or stomach to those with negative colonoscopic examination. Sensitivity and specificity for CA 19-9 and CEA were calculated using the following clinical definitions. Malignant or pre-malignant disease was defined as colon, pancreatic or stomach carcinoma, stomach dysplasia, atypical adenomatous polyp, atypical villous adenoma, carcinoma in situ and carcinoma in an adenomatous polyp. When the normal group included patients with adenomatous polyp, hyperplastic adenoma, inflammatory disease and patients with no disease apparent, the sensitivity and specificity for CA 19-9 was 23% and 96%, and for CEA, 23% and 95%, respectively. When adenomatous polyp patients were placed in the malignant or pre-malignant disease group, the sensitivity and specificity for CA 19-9 was 8% and 96%, and for CEA, 11% and 95%, respectively. When comparing CA 19-9 and CEA in colorectal carcinoma, the percent positivity of the CEA assay was equal to, or better than, CA 19-9 in all Dukes' stages. In pancreatic carcinomas CA 19-9 showed better diagnostic performance than CEA.

Z = 50 shell gap near 100Sn from intermediate-energy Coulomb excitations in even-mass 106-112Sn isotopes.

Rare isotope beams of neutron-deficient 106,108,110Sn from the fragmentation of 124Xe were employed in an intermediate-energy Coulomb excitation experiment. The measured B(E2,0(1)(+)-->2(1)(+)) values for 108Sn and 110Sn and the results obtained for the 106Sn show that the transition strengths for these nuclei are larger than predicted by current state-of-the-art shell-model calculations. This discrepancy might be explained by contributions of the protons from within the Z = 50 shell to the structure of low-energy excited states in this region.

Measurement of excited states in (40)Si and evidence for weakening of the N=28 shell gap.

Excited states in (40)Si have been established by detecting gamma rays coincident with inelastic scattering and nucleon removal reactions on a liquid hydrogen target. The low excitation energy, 986(5) keV, of the 2(1)(+) state provides evidence of a weakening in the N=28 shell closure in a neutron-rich nucleus devoid of deformation-driving proton collectivity.

Probing shell structure and shape changes in neutron-rich sulfur isotopes through transient-field g-factor measurements on fast radioactive beams of 38S and 40S.

The shell structure underlying shape changes in neutron-rich nuclei near N = 28 has been investigated by a novel application of the transient-field technique to measure the first-excited-state g factors in 38S and 40S produced as fast radioactive beams. There is a fine balance between proton and neutron contributions to the magnetic moments in both nuclei. The g factor of deformed 40S does not resemble that of a conventional collective nucleus because spin contributions are more important than usual.

Quadrupole deformation of the self-conjugate nucleus 72Kr.

We report on the first determination of the absolute B(E2;0+(1)-->2+(1)) excitation strength in the N=Z nucleus 72Kr. 72Kr is the heaviest N=Z nucleus for which this quantity has been measured and provides a benchmark in a region of the nuclear chart dominated by rapidly changing deformations and shapes mediated by the interplay of strongly oblate and prolate-driving orbitals. The deduced quadrupole deformation strength is in agreement with a variety of self-consistent models that predict an oblate shape for the ground state of 72Kr. Large-scale shell-model Monte Carlo calculations reproduce the experimental B(E2) value and link the result to the occupation of the deformation-driving g9/2 orbit.

29Na: defining the edge of the island of inversion for Z=11.

The low-energy level structure of the exotic Na isotopes (28,29)Na has been investigated through beta-delayed gamma spectroscopy. The N=20 isotones for Z=10-12 are considered to belong to the "island of inversion" where intruder configurations dominate the ground state wave function. However, it is an open question as to where and how the transition from normal to intruder dominated configurations happens in an isotopic chain. The present work, which presents the first detailed spectroscopy of (28,29)Na, clearly demonstrates that such a transition in the Na isotopes occurs between 28Na (N=17) and 29Na (N=18), supporting the smaller N=20 shell gap in neutron-rich sd shell nuclei. The evidence for inverted shell structure is found in beta-decay branching ratios, intruder dominated spectroscopy of low-lying states, and shell model analysis.

Half-life of the doubly magic r-process nucleus 78Ni.

Nuclei with magic numbers serve as important benchmarks in nuclear theory. In addition, neutron-rich nuclei play an important role in the astrophysical rapid neutron-capture process (r process). 78Ni is the only doubly magic nucleus that is also an important waiting point in the r process, and serves as a major bottleneck in the synthesis of heavier elements. The half-life of 78Ni has been experimentally deduced for the first time at the Coupled Cyclotron Facility of the National Superconducting Cyclotron Laboratory at Michigan State University, and was found to be 110(+100)(-60) ms. In the same experiment, a first half-life was deduced for 77Ni of 128(+27)(-33) ms, and more precise half-lives were deduced for 75Ni and 76Ni of 344(+20)(-24) ms and 238(+15)(-18) ms, respectively.

Asymmetric septal hypertrophy of the heart. New findings concerning the possible etiology of sudden deaths in five males.

This report describes certain interesting postmortem findings in the hearts of five subjects who died suddenly, silently, and unexpectedly, and in whom the only significant abnormality at autopsy was asymmetric septal hypertrophy (ASH) of the heart. Deep clefts, cystic faults, and dilated vascular channels were not only seen within the septal myocardium in all the hearts, but also within the left ventricular free walls of two hearts. The septal myocardium and the left ventricular free walls of two hearts and the A-V node and His bundle of one heart demonstrated mural and luminal thrombi of several dilated vascular channels. In another heart, foci of cardiocytic myofibrillar degeneration were seen, especially close to narrowed small coronary vessels. Fetal dispersion and fibrosis of the A-V node and His bundle were evident in one heart. These abnormalities in the conducting system and the ventricular myocardium suggest that the hearts of subjects with ASH are not only excellent anatomic substrates for lethal arrhythmias, but also are bound to be hemodynamically impaired. We believe that conditions such as hypoxia, increased oxygen demand by the heart or abnormal sympathetic stimulus may easily trigger fatal arrhythmias in such individuals, thereby causing sudden death.

The role of the chimpanzee in the evaluation of the risk of foreign chemicals to man.

Various species of laboratory animals are used to evaluate the efficacy and safety of drugs in man. However, the extrapolation of data from animals to man is often complicated by species differences in the disposition of foreign chemicals. The findings of comparative metabolism studies are used to illustrate species differences in metabolic pathways, rates of biotransformation, kinetics, and excretion routes. Biochemical and structural consequences of the significant differences in enzyme induction between rodents and primate species are discussed. Among the primates, the chimpanzee has been shown to be the most closely related to man not only in the disposition of xenobiotics, but also in the aspects of endocrinology, serology, and immunology. It would, therefore, be the best possible model to predict the fate and effects of foreign chemicals in man. Due to the limited availability of chimpanzees, however, they can only be used for the evaluation of the most critical chemicals and drugs. Comparative metabolism and disposition studies, e.g., of compounds representative of classes of chemicals in chimpanzees and other animals. Only when the pertinent differences between the selected test species and man are known can correct extrapolations to man be made.

Fulminant disseminated toxoplasmosis in an HIV patient.

Disseminated toxoplasmosis in AIDS is a rare condition. We present an unusual case of a fulminant form of disseminated toxoplasmosis in a young male homosexual. He was a 30-year-old HIV-positive (diagnosed 4 months earlier), admitted with a 5-day history of diarrhea, vomiting, fever, and cough. He had been generally healthy except for an 8-week history of weight loss and malaise. On admission, except for a temperature of 37.6 degrees C, the physical examination was normal. He was treated symptomatically. Four days after admission he suddenly became short of breath. Despite intensive management, he continued to deteriorate and expired 6 h later. Postmortem examination revealed disseminated toxoplasmosis involving the heart, lungs, brain, stomach, small intestine, and colon. This is an unusual presentation of disseminated toxoplasmosis because of its rapid course with no prior indication of infection. To our knowledge, such an atypical and rapid downhill course of toxoplasmosis (with minimal clinical and laboratory features) has not been reported previously. Increased awareness of this infection in all HIV patients and its possibly rapid course is needed.

A fatal maprotiline intoxication.

A fatal maprotiline intoxication is presented. The postmortem anatomical and toxicologic findings are discussed, as is the mechanism of maprotiline toxicity. This report is, to the best of our knowledge, the sixth fatal maprotiline poisoning in the medical literature.

Distribution of cyclosporine in blood of a renal-transplant recipient with type V hyperlipoproteinemia.

A patient with severe type V hyperlipoproteinemia and chronic end-stage renal disease received a renal transplant and therapy with cyclosporine. Concentrations of the drug in plasma as determined by liquid chromatography appeared extraordinarily high for the dose ingested. When we measured the drug in the plasma, plasma cleared by ultracentrifugation, leukocytes, erythrocytes, and whole blood, we found that the high concentrations of cyclosporine were associated with the chylomicrons that always were present in this patient's blood. Cyclosporine added directly to this patient's plasma was less associated with the plasma lipids. Isolated lymphocytes and kidney slices incubated with plasma from this patient bound no more drug than when incubated with nonhyperlipemic plasma containing cyclosporine at a normal therapeutic concentration. We conclude that the cyclosporine associated with the chylomicrons in this patient was not biologically available to either lymphocytes or kidney tissue. We strongly recommend the use of chylomicron-cleared plasma for therapeutic drug monitoring of cyclosporine in type V hyperlipoproteinemic patients.