Evaluation of the latex-agglutination test for the diagnosis of invasive amebiasis

Summary A new test for the diagnosis of invasive amebiasis is evaluated. There were 96 positive results in 100 proved cases of both hepatic abscesses and intestinal amebiasis; there were 5 per cent false-positive results in the control group of 200 cases. The authors recommend the test as an aid to the clinical study of the patient, especially when the differential diagnosis is difficult to establish. Read at the meeting of the American Proctologic Society, New York, New York, June 11 to 14, 1972.     

An artificial sphincter: A preliminary report

Summary A new method of providing continence to patients with fecal stomas is presented. The device, used as an artificial sphincter, consists of an inflatable Silastic balloon, which is implanted in the subcutaneous tissue around the stoma; it is easily handled by the patient. The artificial sphincter was used in six patients with colostomies. In all cases, satisfactory continence of the stoma was achieved, obviating the need to use enemas, bags or other appliances. In three patients subcutaneous infections developed around the prosthesis. In two cases, this was readily controlled; in one case, the prosthesis had to be removed. The other five patients are well and continent. None of the patients experienced pain or discomfort during use of the prosthesis. There has been no stomal ischemia. Read at the meeting of the American Society of Colon and Rectal Surgeons, San Diego, California, June 11 to 15, 1978.     

Charge of a quasiparticle in a superconductor

Nonlinear charge transport in superconductor–insulator–superconductor (SIS) Josephson junctions has a unique signature in the shuttled charge quantum between the two superconductors. In the zero-bias limit Cooper pairs, each with twice the electron charge, carry the Josephson current. An applied bias V_SD leads to multiple Andreev reflections (MAR), which in the limit of weak tunneling probability should lead to integer multiples of the electron charge ne traversing the junction, with n integer larger than 2Δ/eV_SD and Δ the superconducting order parameter. Exceptionally, just above the gap eV_SD ≥ 2Δ, with Andreev reflections suppressed, one would expect the current to be carried by partitioned quasiparticles, each with energy-dependent charge, being a superposition of an electron and a hole. Using shot-noise measurements in an SIS junction induced in an InAs nanowire (with noise proportional to the partitioned charge), we first observed quantization of the partitioned charge q = e*/e = n, with n = 1–4, thus reaffirming the validity of our charge interpretation. Concentrating next on the bias region eV_SD ～ 2Δ, we found a reproducible and clear dip in the extracted charge to q? ～ 0.6, which, after excluding other possibilities, we attribute to the partitioned quasiparticle charge. Such dip is supported by numerical simulations of our SIS structure.Excitations in superconductors (Bogoliubov quasiparticles) can be described according to the Bardeen–Cooper–Schrieffer (BCS) theory (1) as an energy-dependent superposition of an electron with amplitude u(ε), and a hole with amplitude v(ε), where the energy ε is measured relative to the Fermi energy (2). Evidently, the expectation value of the charge operator (applied to the quasiparticle wave function), which we address as the quasiparticle charge e* = q(ε)e, is smaller than the charge of an electron, q(ε) = |u(ε)|² ? |ν(ε)|² (3). Solving the Bogoliubov–de Gennes equations, one finds that |u(ε)|2=1/2[1+(ε2−Δ2/ε)] and |v(ε)|2=1/2[1−(ε2−Δ2/ε)], with the expected charge evolving with energy according to q(ε)=ε2−Δ2/ε––vanishing altogether at the superconductor gap edges (3). Note, however, that the quasiparticle wave function is not an eigenfunction of the charge operator (3, 4). Properties of quasiparticles, such as the excitation spectra (5), lifetime (6–10), trapping (11), and capturing by Andreev bound states (12, 13), had already been studied extensively; however, studies of their charge are lagging. In the following we present sensitive shot-noise measurements in a Josephson junction, resulting in a clear observation of the quasiparticle charge being smaller than e, q(eV_SD∼2Δ) < 1, and evolving with energy, as expected from the BCS theory.To observe the BCS quasiparticles in transport we study a superconductor–insulator–superconductor (SIS) Josephson junction in the nonlinear regime. The overlap between the wave functions of the quasiparticles in the source and in the drain is expected to result in a tunneling current of their effective charge. This is in contrast with systems which are incoherent (14, 15) or with an isolated superconducting island, where charge conservation leads to traversal of multiples of e – Coulomb charge (16). As current transport in the nonlinear regime results from “multiple Andreev reflections” (MAR), it is prudent to make our measurements credible by first measuring the charge in this familiar regime.In short, the MAR process, described schematically in Fig. 1, carries a signature of the shuttled charge between the two superconductors (SCs), being a consequence of n traversals through the junction (as electron-like and hole-like quasiparticles), with n an integer larger than 2Δ/eV_SD. A low transmission probability t (via tunneling through a barrier) in the bias range 2Δ/n < eV_SD < 2Δ/(n ? 1) assures dominance of the lowest order MAR process (higher orders are suppressed as tⁿ), with the charge evolving in nearly integer multiples of the electron charge. Although there is already a substantial body of theoretical (3, 17–23) and experimental (24–29) studies of the MAR process, charge determination without adjustable parameters is still missing. An important work by Cron et al. (27) indeed showed a staircase-like behavior of the charge using “metallic break junctions;” however, limited sensitivity and the presence of numerous conductance channels some of which with relatively high transmission probabilities did not allow exact charge quantization. Our shot-noise measurements, performed on a quasi-1D Josephson junction (single-mode nanowire) allowed clear observation of charge quantization without adjustable parameters. To count a few advantages: (i) the transmission of the SIS junction could be accurately controlled using a back-gate; (ii) this, along with our high sensitivity in noise measurements, enabled us to pinch the junction strongly (thus suppressing higher MAR orders); and (iii) with the Fermi level located near the 1D channel van Hove singularity, a rather monoenergetic distribution could be injected (SI Appendix, section S7).Open in a separate windowFig. 1.MAR. Illustrations of the leading processes contributing to the current as function of bias. In general, for 2Δ/(n ? 1) > eV_SD > 2Δ/n the leading charge contribution to the current is ne. An electron-like quasiparticle is denoted by a full circle, whereas a hole-like quasiparticle is denoted by an empty circle. (A) When the bias is larger than the energy gap, eV_SD > 2Δ, the leading process is a single-path tunneling of single quasiparticles from the full states (Left) to the empty states (Right). This current is proportional to the transmission coefficient t. Higher-order MAR process (dashed box), being responsible for tunneling of Cooper pairs, is suppressed as t². (B) For 2Δ > eV_SD > Δ, the main charge contributing to the current is 2e with probability t². (C) For Δ > eV_SD > 2Δ/3, the main charge contributing to the current is 3e with probability t³.     

Maternal Adnexal Torsion in Pregnancy Is Associated with Significant Risk of Recurrence

Study ObjectivesTo investigate the phenomenon of recurrent adnexal torsion during the same pregnancy, describe its risk factors, and suggest possible management of this entity.DesignRetrospective case-control study (Canadian Task Force classification II-3).SettingGynecologic endoscopy unit in a university hospital.Patients and interventionsPregnant women with surgically proved adnexal torsion were retrospectively identified from 1993 to 2007. Details of clinical presentation, method of conception, preoperative ultrasound findings, and operative findings were analyzed.InterventionComparison of characteristics of patients with recurrent episodes of adnexal torsion during the same pregnancy vs a single episode of torsion.Measurements and Main ResultsThirty-three pregnant women with 38 episodes of adnexal torsion were included in the study. Seventeen pregnancies (51.5%) were spontaneously conceived. Twenty-eight women had a single episode of torsion, and 5 women (15.1%) had recurrent episodes of torsion during the same pregnancy. No significant differences were found between the 2 groups in age, method of conception, and gestational age at time of torsion. However, ultrasound studies demonstrated that multicystic ovaries were significantly more common in women with recurrent torsion compared with women with a single episode of torsion (80% vs 25%; p = .02). The interval between the first and second episodes of torsion ranged from 1 to 4 weeks.ConclusionPregnant women are at risk for recurrent torsion, especially when the ovaries are enlarged and ultrasound studies demonstrate multiple cysts. Cyst aspiration may prevent recurrent torsion during the same pregnancy.     

Die Wirkung des D,L-Glycerinaldehyds und mit ihm chemisch verwandter Stoffe auf die experimentelle Mäuse-Hämoblastose L 14 AKR in vivo

Zusammenfassung Experimente wurden durchgeführt, um die in vivo-Wirkung des D,L-Glycerinaldehyds, Acroleins und 1,2-Dibrompropanals-3 auf eine experimentelle Leukämie zu untersuchen. Es wurde festgestellt, daß ein direkter Kontakt dieser Stoffe mit den leukämischen Leukocyten eine besondere Bedeutung für die Therapie hat.

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Summary Experiments were carried out to study the in-vivo effect of D,L-glycerinaldehyde, acroleine, and 1,2-dibrompropanale-3 on the course of an experimental leukemia. It could be shown that the direct contact of these drugs with the ukemic leukocytes is of special importance for the effect of therapy.

     

Distinct features of dehydrocorticosterone reduction into corticosterone in the liver and duodenum of the domestic fowl (Gallus gallus domesticus)

The mammalian 11-beta hydroxysteroid dehydrogenase type 1 (11 betaHSD1) reduces glucocorticoids (GC) at C11 from the 11-keto-GC nonactive form to the 11-hydroxy-GC active form, an action essential for survival. Whereas GC metabolism at C11 and the role of 11 betaHSD1 are studied extensively in mammals, information about these in birds is scattered. Herein, we report the GC bidirectional metabolism in chickens. In hens' liver and duodenal mucosa, 11 betaHSD1-like mRNA expression was detected; and 11 betaHSD1-like immunoreactivity was found linked to membranes of hepatocytes and duodenal enterocytes. With either NADH or NADPH, the membranal fraction of liver and duodenal mucosa converted dehydrocorticosterone (A) into corticosterone (B) with K(m) (1.1-8.7 microM) and V(max) (10-40 pmol/mg protein/min) values similar to those reported for mammalian 11 betaHSD1. In the presence of NADP(+) or NAD(+), these membranal fractions oxidized B into A. With either NADPH or NADH, the cytosol of chicken liver and duodenal mucosa reduced A into B (K(m) of 1.1 - 2.3 microM and V(max) of 260-960 pmol/mg protein/min). These cytosolic fractions did not convert any amount of B into A when incubated with either NADP(+) or NAD(+). This may suggest that chicken liver and duodenal mucosa express 11 betaHSD1 that is a membrane-bound oxoreductase which uses both NADPH/NADP(+) and NADH/NAD(+) as cosubstrates. The substantial reduction of A into B (but no conversion of B into A) found in the cytosol is most likely executed by a unidirectional soluble reductase, different than 11 betaHSD1.     

An evaluation of the amebicidal properties of metronidazole

Summary Twenty patients with amebic ulcerative proctitis were treated with metronidazole. The rate of cure was 90 per cent. Metronidazole caused slight side-effects in 15 per cent of the patients. The authors believe that the optimal treatment schedule is 800 mg three times a day for 20 days. Read at the meeting of the American Proctologic Society, Boston, Massachusetts, June 16 to 18, 1969.     

The major histopathologic characteristics in the vulvar vestibulitis syndrome

OBJECTIVE: In order to better understand the etiology of the vulvar vestibulitis syndrome, we examined the histopathologic parameters in vestibular mucosa, and compared the findings in specimens obtained from women with vulvar vestibulitis with those obtained from the control group. STUDY DESIGN: Specimens of vestibulitis were obtained from 24 patients, undergoing circumferential vestibulectomy under general anesthesia due to the symptoms and signs consistent with vulvar vestibulitis. Control specimens were obtained from 16 women, without symptoms or signs of vulvar vestibulitis, undergoing reconstructive introital surgery due to roomy vagina, rectocele or painful episiotomy. All vestibular tissue specimens were examined for intensity of inflammation, extension of inflammatory cells into the epithelium, vascular proliferation, the presence of mast cells and proliferation of peripheral nerve bundles. RESULTS: No significant difference was found regarding the degree of inflammation, the extension of inflammatory cells into the epithelium, the vascular proliferation and the presence of mast cells while comparing the study and the control groups. The only histopathologic feature, differentiating the patients with vulvar vestibulitis from the control group, was the proliferation of peripheral nerve bundles found in 19 out of 24 (79.1%) specimens expressing vestibulitis and in none of 16 control specimens (p < 0.0001). CONCLUSION: Our results, therefore, support the existence of peripheral nerve hyperplasia in vestibular tissue obtained from patients with vulvar vestibulitis, and exclude the role of active inflammation or mast cells as probable etiologies for the vulvar vestibulitis syndrome.