Monoclonal Antibodies as a Therapeutic Strategy against Multidrug-Resistant Bacterial Infections in a Post-COVID-19 Era

The development of severe multidrug-resistant bacterial infections has recently intensified because of the COVID-19 pandemic. According to the guidelines issued by the World Health Organization (WHO), routine antibiotic administration is not recommended for patients with supposed or confirmed mild SARS-CoV-2 infection or pneumonia, unless bacterial infection is clinically suspected. However, recent studies have pointed out that the proportion of non-essential antibiotic use in patients infected with SARS-CoV-2 remains high. Therefore, the silent pandemic of antibiotic resistance remains a pressing issue regardless of the present threats presented by the COVID-19 pandemic. To prevent or delay entry into the postulated post-antibiotic era, the long-term advocacy for the rational use of antibiotics, the optimization of infection control procedures, and the development of new antibacterial agents and vaccines should be underscored as vital practices of the antibacterial toolbox. Recently, the development of vaccines and monoclonal antibodies has gradually received attention following the advancement of biotechnology as well as enhanced drug discovery and development in cancer research. Although decent progress has been made in laboratory-based research and promising results have been obtained following clinical trials of some of these products, challenges still exist in their widespread clinical applications. This article describes the current advantages of antibacterial monoclonal antibodies, the development of associated clinical trials, and some perceived future perspectives and challenges. Further, we anticipate the development of more therapeutic agents to combat drug-resistant bacterial infections as well as to increase the resilience of current or novel agents/strategies.

First-principles prediction on antimony-doping effects on the cyclic stability of tin anodes for lithium-ion batteries

Tin-based materials are considered as promising anode materials for advanced Li-ion batteries (LIBs) due to their relatively high capacity and suitable working voltage, but they suffer from poor structural stability during electrochemical cycling. Herein, we present the possibility that the cyclic stability of the Sn LIB anode can be enhanced by adding a small amount of antimony (Sb), based on first-principles investigation of lithiation behavior of amorphous Sn doped with 3 at% Sb. At low Li contents (x < 1.5 in a-Li_xSn_0.97Sb_0.03), our simulations show that the preferential reaction of Li with Sb over Sn tends to lead to the formation of small lithiated Sb clusters. However, the aggregated Sb, if any, become fully separated upon further lithiation, implying that they may remain well dispersed in the lithiation/delithiation process if the Sb-doping concentration is sufficiently low. The weak aggregation and preferential lithiation tendency of Sb in the Sb-doped Sn anode can be expected to contribute to enhancing its structural stability during cycling, in comparison with pure Sn and SnSb alloy cases. We also compare lithiation-induced changes in the electrochemical, transport and mechanical properties between the Sb-doped and pure Sn systems. Our study highlights the importance of low concentration and uniform distribution of Sb in order to obtain desired properties of Sb-doped Sn as an anode for LIBs. This finding also provides some hints for the further development of Sn-based anodes via fine-tuning of doping.

[An interlaboratory comparison study on the detection of RUNX1-RUNX1T1 fusion transcript levels and WT1 transcript levels]

Objective: To investigate the current status and real performance of the detection of RUNX1-RUNX1T1 fusion transcript levels and WT1 transcript levels in China through interlaboratory comparison. Methods: Peking University People's Hospital (PKUPH) prepared the samples for comparison. That is, the fresh RUNX1-RUNX1T1 positive (+) bone morrow nucleated cells were serially diluted with RUNX1-RUNX1T1 negative (-) nucleated cells from different patients. Totally 23 sets with 14 different samples per set were prepared. TRIzol reagent was added in each tube and thoroughly mixed with cells for homogenization. Each laboratory simultaneously tested RUNX1-RUNX1T1 and WT1 transcript levels of one set of samples by real-time quantitative PCR method. All transcript levels were reported as the percentage of RUNX1-RUNX1T1 or WT1 transcript copies/ABL copies. Spearman correlation coefficient between the reported transcript levels of each participated laboratory and those of PKUPH was calculated. Results: ①RUNX1-RUNX1T1 comparison: 9 samples were (+) and 5 were (-) , the false negative and positive rates of the 20 participated laboratories were 0 (0/180) and 5% (5/100) , respectively. The reported transcript levels of all 9 positive samples were different among laboratories. The median reported transcript levels of 9 positive samples were from 0.060% to 176.7%, which covered 3.5-log. The ratios of each sample's highest to the lowest reported transcript levels were from 5.5 to 12.3 (one result which obviously deviated from other laboratories' results was not included) , 85% (17/20) of the laboratories had correlation coefficient ≥0.98. ②WT1 comparison: The median reported transcript levels of all 14 samples were from 0.17% to 67.6%, which covered 2.6-log. The ratios of each sample's highest to the lowest reported transcript levels were from 5.3-13.7, 62% (13/21) of the laboratories had correlation coefficient ≥0.98. ③ The relative relationship of the reported RUNX1-RUNX1T1 transcript levels between the participants and PKUPH was not always consistent with that of WT1 transcript levels. Both RUNX1-RUNX1T1 and WT1 transcript levels from 2 and 7 laboratories were individually lower than and higher than those of PKUPH, whereas for the rest 11 laboratories, one transcript level was higher than and the other was lower than that of PKUPH. Conclusion: The reported RUNX1-RUNX1T1 and WT1 transcript levels were different among laboratories for the same sample. Most of the participated laboratories reported highly consistent result with that of PKUPH. The relationship between laboratories of the different transcript levels may not be the same.

Immunohistochemical localization of sex hormone receptors in two Raillietina tapeworms

Sex hormone receptors play critical roles in development and reproduction. However, it is not known whether they exist in Raillietina tapeworms, and if they do, whether they have a similar function to that in vertebrates. We examined the immunohistochemical distributions of androgen receptors (ARs), estrogen receptors (ERs), and progesterone receptors (PRs) in the tissues of two tapeworm species: Raillietina echinobothrida and Raillietina tetragona. Immunopositive ARs were found in the entire reproductive system of R. echinobothrida, including the testes, ovaries, and oocysts, and weakly immunopositive ERs and PRs were found in the testes, ovaries, and oocysts. Immunopositive ARs were also found throughout the entire reproductive system of R. tetragona, including the testes, ovaries, and oocysts, and weakly immunopositive ERs were in the testes and oocysts; the PRs were distributed in an immunonegative manner. The results show that androgens and their receptors play critical roles in reproductive system development in the two tapeworms. The immunoreactivity and tissue localizations of the sex hormone receptors suggest that, in both species, they have similar functions as in vertebrates, and modulate reproduction.

Auditory efferent dysfunction in normal-hearing chronic idiopathic tinnitus

OBJECTIVE

To investigate the function of the auditory efferent system in patients with chronic idiopathic tinnitus, but normal pure-tone audiograms.

METHODS

We studied 15 subjects with normal hearing that had experienced either unilateral or bilateral persistent tinnitus for at least 3 months. The ears of the 15 subjects were classified into tinnitus-positive-ear (TPE) and tinnitus-negative-ear (TNE) groups. The control-ear group (CE) comprised the ears of 15 subjects with normal hearing and no tinnitus. We measured different types of otoacoustic emissions (OAEs), including spontaneous (SOAEs), transient evoked (TEOAEs), and distortion product (DPOAEs). We also analyzed contralateral suppression of OAEs and auditory brainstem responses (ABRs). Data were compared among TPE, TNE, and CE groups.

RESULTS

The data associated with cochlear mechanics, including the prevalence of SOAEs, the number of SOAE peaks, and the overall TEOAE responses in the absence of a contralateral stimulus, were not significantly different among the TPE, TNE, and CE groups. In the TPE group, contralateral stimuli failed to significantly suppress overall TEOAEs, and contralateral suppression of DPOAEs was significantly reduced over a limited frequency range. Furthermore, the TPE group showed prolonged latencies in waves III and V of ABRs.

CONCLUSION

This study demonstrated that abnormal contralateral suppression of OAEs and ABRs indicated a dysfunction in the ipsilateral efferent medial olivocochlear system; this might play a role in normal-hearing tinnitus.

Photoconduction mechanism of oxygen sensitization in InN nanowires

The photoconduction (PC) mechanism in indium nitride (InN) nanowires (NWs) has been investigated via environment-, temperature-, and power-dependent measurements. The adsorbed oxygen-induced modulation of the surface state is proposed to be the leading factor in the long lifetime or high gain transport and in sensitizing photocurrent generation in the InN NWs. The electron trapping effect by adsorbed oxygen can be verified by the increased activation energy from 33 ± 4 (in vacuum) to 58 ± 2 meV (in oxygen). The observed supralinear power dependence of photocurrent also suggests the presence of acceptor states that influence the carrier recombination behavior and compensate the thermal carriers in the InN NWs. The potential influence of native oxide on the molecule-sensitive PC in this nitride nanomaterial is also inferred.

Model-based segmentation of flexor tendons from magnetic resonance images of finger joints

Trigger finger is a common hand disease, causing swelling, painful popping and clicking in moving the affected finger joint. To better evaluate patients with trigger finger, segmentation of flexor tendons from magnetic resonance (MR) images of finger joints, which can offer detailed structural information of tendons to clinicians, is essential. This paper presents a novel model-based method with three stages for automatically segmenting the flexor tendons. In the first stage, a set of tendon contour models (TCMs) is initialized from the most proximal cross-sectional image via two-step ellipse estimation. Each of the TCMs is then propagated to its distally adjacent image by affine registration. The propagation is sequentially performed along the proximal-distal direction until the most distal image is reached, as the second stage of segmentation. The TCMs on each cross-sectional image are refined in the last stage with the snake deformation. MR volumes of three subjects were used to validate the segmentation accuracy. Compared with the manual results, our method showed good accuracy with small average margins of errors (within 0.5 mm) and large overlapping ratio (dice similarity coefficient above 0.8). Overall, the proposed method has great potential for morphological change assessment of flexor tendons and pulley-tendon system modeling for image guided surgery.

Computational modeling of ultraviolet disinfection

The efficient design of ultraviolet light (UV) systems for water and wastewater treatment requires detailed knowledge of the patterns of fluid motion that occur in the disinfection channel. This knowledge is increasingly being obtained using Computational Fluid Dynamics (CFD) software packages that solve the equations governing turbulent fluid-flow motion. In this work, we present predictions of the patterns of flow and the extent of disinfection in a conventional reactor consisting of an open channel with an array of UV lamps placed with their axes perpendicular to the direction of flow. It is shown that the resulting flow is inherently unsteady due to the regular shedding of vortices from the submerged lamps. It is also shown that the accurate prediction of the hydraulic residence time and, consequently, the extent of disinfection is strongly dependent on the ability of the CFD method to capture the occurrence and strength of the vortex shedding, and its effects on the turbulent mixing processes.

Neural correlates of antisaccade deficits in schizophrenia, an fMRI study

Schizophrenia patients were known to have oculomotor abnormalities for decades and several studies had found antisaccade impairment to be a biological marker of schizophrenia. In this study, we used functional magnetic resonance imaging (fMRI) to investigate the neural circuits responsible for antisaccade deficits in schizophrenia. Ten normal controls and 10 DSM-IV schizophrenia patients performed antisaccade tasks and control tasks during fMRI. Data were analyzed and task-specific activations were identified using Statistical Parametric Mapping (SPM-2). In normal subjects, antisaccade tasks activated bilateral frontal eye fields, supplementary eye fields, inferior frontal gyrus, superior parietal lobules, inferior parietal lobules, occipital visual cortex, cerebellum, thalamus, and lentiform nuclei (P<0.001). By contrast, schizophrenia patients failed to show activation in bilateral lentiform nucleus, bilateral thalamus, and left inferior frontal gyrus during antisaccade performance. Our findings suggest that schizophrenic antisaccade deficits are associated with dysfunction of fronto-striatal-thalamo-cortical circuits previously demonstrated to be responsible for suppression of the reflexive saccade. Left inferior frontal gyrus, which was known to be responsible for response inhibition on "go/no-go" testing, also plays an important role in schizophrenic antisaccade deficit.

An integrated healthcare enterprise information portal and healthcare information system framework

The paper presents an integrated, distributed Healthcare Enterprise Information Portal (HEIP) and Hospital Information Systems (HIS) framework over wireless/wired infrastructure at National Taiwan University Hospital (NTUH). A single sign-on solution for the hospital customer relationship management (CRM) in HEIP has been established. The outcomes of the newly developed Outpatient Information Systems (OIS) in HIS are discussed. The future HEIP blueprints with CRM oriented features: e-Learning, Remote Consultation and Diagnosis (RCD), as well as on-Line Vaccination Services are addressed. Finally, the integrated HEIP and HIS architectures based on the middleware technologies are proposed along with the feasible approaches. The preliminary performance of multi-media, time-based data exchanges over the wireless HEIP side is collected to evaluate the efficiency of the architecture.

Separation of gamma-globulins from porcine plasma by reversed micellar extraction

Factors affecting the separation of gamma-globulins from porcine plasma using reversed micelles were screened based on a fractional factorial design. The optimal processing conditions for obtaining the maximum yield of gamma-globulins under various constraints of product purity were determined using response surface methodology (RSM) and nonlinear programming. Results showed that the pH and sodium chloride concentration of the aqueous phase, and the concentration of surfactant (bis-(2-ethylhexyl) sulfosuccinate sodium salt, AOT) of the organic phase were the most important factors affecting the extraction performance. An eighty-five percent product purity and ninety-seven percent yield were obtained under the extraction conditions of 400 mM NaCl, 350 mM AOT, and pH 7.0. The extract exhibited immunological reactivity against anti-pig IgG.

Epstein-Barr virus-associated recurrent necrotic papulovesicles with repeated bacterial infections ending in sepsis and death: consideration of the relationship between Epstein-Barr virus infection and immune defect

The disease of Epstein-Barr virus (EBV) -associated recurrent necrotic papulovesicles is a distinct clinicopathologic entity different from classic hydroa vacciniforme (HV). A few patients have been reported as atypical HV with systemic involvement, development of lymphoma, and poor prognosis. We describe a patient with recurrent necrotic papulovesicles and multiple varioliform scars in both sun-exposed and covered areas. In contrast to cases of previously reported atypical HV, our patient suffered from repeated bacterial infections on various sites ending in sepsis and death, but without malignant transformation. EBV was detected in the lymphoid cells from the skin lesions by anti-latent membrane protein (LMP) antibody and in situ hybridization. We suggest that the repeated bacterial infections in this case raise the possibility of an association of EBV infection with increased susceptibility to bacterial infections.

Novel cell immobilization method utilizing centrifugal force to achieve high-density hepatocyte culture in porous scaffold

Cell seeding is one of the key procedures in the construction of tissue-engineered organs. In our previous efforts to create a bioartificial liver, high-density cultures of hepatocytes (>1 x 10(7) cells/1 cm(3)-substrate) and long-term maintenance of metabolic function were achieved with a packed-bed reactor utilizing porous poly(vinyl formal) (PVF) resin as a scaffold. However, a low seeding efficiency of about 30% remains a major obstacle to the scaleup of the reactor. In the present study, a new cell seeding method, centrifugal cell immobilization (CCI), which is based on alternating centrifugation and resuspension, was used to achieve high-density seeding and improve the seeding efficiency. Using the CCI method, the maximum density of the immobilized hepatocytes reached 3.8 x 10(7) cells/1 cm(3)-PVF, and the seeding efficiency was improved to about 43% after a relatively short immobilization process (about 15 min). Moreover, further improvement of the seeding efficiency was obtained by serial immobilization procedures. Thus, we concluded that this method is useful and effective for seeding cells into 3-dimensional scaffolds.

A specific molar ratio of stabilizer to protein is required for storage stability of a lyophilized monoclonal antibody

The selection of the appropriate excipient and the amount of excipient required to achieve a 2-year shelf-life is often done by using iso-osmotic concentrations of excipients such as sugars (e.g., 275 mM sucrose or trehalose) and salts. Excipients used for freeze-dried protein formulations are selected for their ability to prevent protein denaturation during the freeze-drying process as well as during storage. Using a model recombinant humanized monoclonal antibody (rhuMAb HER2), we assessed the impact of lyoprotectants, sucrose, and trehalose, alone or in combination with mannitol, on the storage stability at 40 degrees C. Molar ratios of sugar to protein were used, and the stability of the resulting lyophilized formulations was determined by measuring aggregation, deamidation, and oxidation of the reconstituted protein and by infrared (IR) spectroscopy (secondary structure) of the dried protein. A 360:1 molar ratio of lyoprotectant to protein was required for storage stability of the protein, and the sugar concentration was 3-4-fold below the iso-osmotic concentration typically used in formulations. Formulations with combinations of sucrose (20 mM) or trehalose (20 mM) and mannitol (40 mM) had comparable stability to those with sucrose or trehalose alone at 60 mM concentration. A formulation with 60 mM mannitol alone provided slightly less protection during storage than 60 mM sucrose or trehalose. The disaccharide/mannitol formulations also inhibited deamidation during storage to a greater extent than the lyoprotectant formulations alone. The reduction in aggregation and deamidation during storage correlated directly with inhibition of unfolding during lyophilization, as assessed by IR spectroscopy. Thus, it appears that the protein must be retained in its native-like state during freeze-drying to assure storage stability in the dried solid. Long-term studies (23-54 months) performed at 40 degrees C revealed that the appropriate molar ratio of sugar to protein stabilized against aggregation and deamidation for up to 33 months. Therefore, long-term storage at room temperature or above may be achieved by proper selection of the molar ratio and sugar mixture. Overall, a specific sugar/protein molar ratio was sufficient to provide storage stability of rhuMAb HER2.

Sweet's syndrome with abscess-like lesions in a patient with acute myelogenous leukemia

We describe a 49-year-old man with acute myelogenous leukemia associated with Sweet's syndrome and abscess-like lesions mimicking an infectious disease. Although blisters may be included in the clinical spectrum, frank non-infectious abscesses have not been reported as far as we know. Clinicians should be familiar with this clinical and histopathologic variant of Sweet's syndrome. It is mandatory to make every effort to find an infectious cause for abscesses before a diagnosis of Sweet's syndrome is made.

Effect of zinc binding and precipitation on structures of recombinant human growth hormone and nerve growth factor

Metal-induced precipitation of protein therapeutics is being used and further developed as a processing step in protein formulation and may have utility in protein purification and bulk storage. In such processes, it is imperative that native protein structure is maintained and the metal complexation is reversible. In the current study, we investigated the effects of zinc-induced precipitation on recombinant human growth hormone (rhGH) and recombinant human nerve growth factor (rhNGF). On the addition of ethylenediaminetetraacetic acid (EDTA), the precipitates were dissolved, yielding complete recovery of native protein in both cases. Both proteins have specific metal binding sites and require specific molar ratios of zinc to protein to initiate precipitation (zinc:rhGH > 2:1; zinc:rhNGF > 18:1). Furthermore, the secondary structures of both proteins were unperturbed in soluble zinc complexes and zinc-induced precipitates, as measured by infrared and circular dichroism spectroscopies. The soluble zinc complex of rhGH had minor tertiary structural alterations, whereas zinc binding did not alter the tertiary structure of rhNGF. These studies indicated that metal-induced precipitation provides a method to maintain proteins in their native state in precipitates, which may be useful for purification, storage, and formulation.

Optimal periodic orbits of continuous time chaotic systems

In previous work [B. R. Hunt and E. Ott, Phys. Rev. Lett. 76, 2254 (1996); Phys. Rev. E 54, 328, (1996)], based on numerical experiments and analysis, it was conjectured that the optimal orbit selected from all possible orbits on a chaotic attractor is "typically" a periodic orbit of low period. By an optimal orbit we mean the orbit that yields the largest value of a time average of a given smooth "performance" function of the system state. Thus optimality is defined with respect to the given performance function. (The study of optimal orbits is of interest in at least three contexts: controlling chaos, embedding of low-dimensional attractors of high-dimensional dynamical systems in low-dimensional measurement spaces, and bubbling bifurcations of synchronized chaotic systems.) Here we extend this previous work. In particular, the previous work was for discrete time dynamical systems, and here we shall consider continuous time systems (flows). An essential difference for flows is that chaotic attractors can have embedded within them, not only unstable periodic orbits, but also unstable steady states, and we find that optimality can often occur on steady states. We also shed further light on the sense in which optimality is "typically" achieved at low period. In particular, we find that, as a system parameter is tuned to be closer to a crisis of the chaotic attractor, optimality may occur at higher period.

Bioequivalence study of tramadol by intramuscular administration in healthy volunteers

Tramadol hydrochloride (CAS 36282-47-0) is a centrally acting analgesic agent binding to mu opiate receptors. The bioavailability of a new tramadol hydrochloride injection (Limadol) was compared with a commercially available reference product by intramuscular administration in twelve healthy Chinese male volunteers by a standard two-way cross-over trial. Each volunteer received a single 100 mg injection of tramadol HCl in each phase. The bioavailability was compared using the area under the plasma concentration-time curve from time 0 to 30 h (AUC0-30), the area under the plasma concentration-time curve from time 0 to infinity (AUC0-infinity), peak plasma concentration (Cmax), and time to reach peak plasma concentration (Tmax). No statistically significant difference was observed between the Tmax, Cmax, AUC0-30 and AUC0-infinity of the two preparations. It is concluded that test and reference formulations of tramadol hydrochloride are bioequivalent for both the extent and rate of absorption after a single intramuscular injection.

Different doses of agonistic ligand drive the maturation of functional CD4 and CD8 T cells from immature precursors

MHC molecules are normally required for the development of thymocytes from the CD4(+)CD8(+) double-positive to the CD4 or CD8 single-positive stage. Here we show that mitogenic plant lectins can substitute for MHC molecules in driving the differentiation of phenotypically and functionally mature CD4 as well as CD8 T cells. Interestingly, lectin dosage determines whether CD4 or CD8 cells are generated, indicating that variation of cumulative signal strength (not necessarily signal quality) can result in an apparent switching of lineage preference. Thymocyte perception of differentiation-inducing signals is modulated by the cellular context, since stimuli that yield CD8 cells in the context of the thymic microenvironment fail to do so in suspension culture and generate CD4 progeny instead. Finally, we show that lectin-generated single-positive thymocytes retain the ability to respond to the ligands initially used to drive their differentiation. Our results call into question generalizations and predictions made from other experimental systems and reveal that thymocyte selection is considerably more flexible than had been anticipated.

Hantavirus infection in Taiwan: the experience of a geographically unique area

Hantaviruses are rodent-borne viruses, and they, mainly the Hantaan (HTN) serotype, are the causative agents of a group of febrile nephropathies known as "hemorrhagic fever with renal syndrome (HFRS). " Despite the fact that HFRS is frequently reported in China, with an annual incidence of 50,000-100,000 cases, one puzzling observation that no local case of HFRS has been confirmed in Taiwan has yet to be explained. We hypothesized that the hantavirus strain prevailing in Taiwan mainly belongs to the mild strain, the Seoul (SEO) strain, and the absence of severe disease was related to the absence of HTN. To test these hypotheses, this epidemiologic study was performed, including a seroprevalence survey and phylogenetic analysis on hantavirus isolated from the rodent population trapped in major seaports, rural, and mountainous areas of Taiwan. This study also included rodents and viruses from two isolated islands, Kinmen and Matzu, which are geographically adjacent to the east coast of mainland China. There were a total of 5,461 rodents of 16 species captured, and R. norvegicus was the most common species, with an antibody prevalence much higher in international seaports (20%) than in rural regions (approximately 5%) and intermediate in some domestic seaports. By reverse transcriptase polymerase chain reaction (RT-PCR), 33.9% of the seropositive R. norvegicus were found to have amplifiable hantavirus sequences in their lung tissues, and subsequent phylogenetic analyses indicated that almost all hantavirus in Taiwan was most closely related to the prototype SEO strain, and no HTN strain was recovered from any rodent species indigenous to Taiwan. The seroprevalence of SEO infection in R. norvegicus on Kinmen and Matzu was also different from that in southern provinces of China but closely resembled that in seaports in Taiwan, and the SEO identified was genetically linked to Taiwanese SEO strains. These results substantiate our hypotheses, and suggest that the epidemiology of hantavirus infection in Taiwan are different from that in China, where the HTN and SEO strains and HFRS concurrently prevail.

Allo-major histocompatibility complex-restricted cytotoxic T lymphocytes engraft in bone marrow transplant recipients without causing graft-versus-host disease

Previous experiments in humans and mice have shown that allogeneic donors can serve as a source of cytotoxic T lymphocytes (CTL) specific for proteins, such as cyclin-D1 and mdm-2, expressed at elevated levels in tumor cells. In vitro, allo-major histocompatibility complex (MHC)-restricted CTL against these proteins selectively killed allogeneic tumor cells, including lymphoma, but not normal control cells. This suggested that these CTL may be useful for adoptive tumor immunotherapy, provided that they (1) survive in MHC-disparate hosts, (2) maintain their killing specificity, and (3) do not attack normal host tissues. Here, we used cloned allo-restricted CTL isolated from BALB/c mice (H-2(d)) that killed H-2(b)-derived tumor cells expressing elevated levels of the mdm-2 target protein. When these CTL were injected into bone marrow transplanted (BMT) C57BL/6 (H-2(b)) recipients, they consistently engrafted and were detectable in lymphoid tissues and in the bone marrow (BM). Long-term survival was most efficient in spleen and lymph nodes, where CTL were found up to 14 weeks after injection. The administration of CTL did not cause graft-versus-host disease (GVHD) normally associated with injection of allogeneic T cells. These data show that allo-restricted CTL clones are promising reagents for antigen-specific immunotherapy in BMT hosts, because they engraft and retain their specific killing activity without causing GVHD.

Efficient strategy for the occasionally proportional feedback method in controlling chaos

In this work, the generic mechanism of the occasionally proportional feedback (OPF) technique in controlling chaos has been explored extensively. Except for stabilizing the unstable states that are embedded in the chaotic attractors, the OPF method is also found to generate a great number of new states during the control processes. The forms and characteristics of these new states have been addressed. Moreover, we clarify the roles of the parameters in the OPF method and this clarification leads to a practical and systematic approach in adjusting the parameters for control. To demonstrate the validity, an analogous electronic circuit of the resistively shunted Josephson junction oscillator is employed in addition to a numerical illustration of the logistic mapping.

Determination of clindamycin in human plasma by liquid chromatography-electrospray tandem mass spectrometry: application to the bioequivalence study of clindamycin

A simple, sensitive and specific liquid chromatography-electrospray tandem mass spectrometry (LC-MS-MS) method for the determination of clindamycin (I) was developed. Both I and verapamil (II, internal standard) were analyzed using a C18 column with a mobile phase of 80% acetonitrile-0.01% trifluoroacetic acid. Column eluents were monitored by electrospray tandem mass spectrometry. Multiple reaction monitoring (MRM) using the parent to daughter combinations of m/z 425-->126 and 455-->165 was used to quantitate I. A limit of quantitation of 0.0500 microgram/ml was found. The assay exhibited a linear dynamic range of 0.0500-20.0 micrograms/ml and gave a correlation coefficient (r2) of 0.998 or better. The chromatographic run time was approximately 2 min. The intra-batch precision and accuracy of the quality controls (QCs, 0.0500, 0.150, 1.50, 15.0 and 20.0 micrograms/ml) were characterized by coefficients of variation (CVs) of 5.13 to 13.7% and relative errors (REs) of -4.34 to 4.58%, respectively. The inter-batch precision and accuracy of the QCs were characterized by CVs of 4.35 to 8.32% and REs of -10.8 to -4.17%, respectively. The method has successfully been applied to the analysis of samples taken up to 12 h after oral administration of 300 mg of I in healthy volunteers.

Use of infrared spectroscopy to assess secondary structure of human growth hormone within biodegradable microspheres

The purpose of this study was to test the utility of infrared (IR) spectroscopy to determine protein secondary structure in biodegradable microspheres. Encapsulation of proteins within biodegradable polymers, [e.g. poly(lactic-co-glycolic acid) (PLGA)] for controlled drug release has recently been the subject of intense research effort. The ability to assess protein integrity after microsphere production is necessary to successfully produce microspheres that release native proteins. We used IR spectroscopy, a noninvasive method-as opposed to conventional organic solvent extraction or in vitro release at elevated temperature-to assess the secondary structure of recombinant human growth hormone (rhGH) within dry and rehydrated microspheres. PLGA microspheres containing rhGH with different excipients were prepared by a conventional double-emulsion method. The protein IR spectra indicated that the encapsulation process could perturb the structure of rhGH and that excipients could inhibit this damage to varying degrees. A strong positive correlation was found between intensity of the dominant alpha-helical band in the spectra of rhGH in rehydrated microspheres and the percent monomer released from microspheres during incubation in buffer. We also studied microspheres prepared with zinc-precipitated rhGH. The addition of Zn2+ during microsphere processing partially inhibited protein unfolding and fostered complete refolding of rhGH upon rehydration. In conclusion, IR spectroscopy can serve as a valuable tool to assess protein structure within both dried and rehydrated microspheres.

The removal of beta-2-microglobulin by an immunoadsorption wall

The accumulation of beta-2-microglobulin (beta2M) in collagen-rich tissues has been proven to be the main cause of dialysis related amyloidosis. However, it remains uncertain which technique for the removal of beta2M can be used without compromising the advantages of other dialysis strategies. A new concept, an immunoadsorption wall, which combines the principles of immunoisolation and immunoadsorption is proposed to remove beta2M. The present investigations suggested that the application of the concept to clinical use is feasible and worthwhile. The concept, if validated, will help shape a novel multitask type of artificial kidney based on the combination of different separation technologies.

High-performance liquid chromatographic determination of clindamycin in human plasma or serum: application to the bioequivalency study of clindamycin phosphate injections

This paper presents an assay of clindamycin phosphate injection in human plasma or serum. A 0.5-ml volume of plasma was used with the internal standard, propranolol. The sample was loaded onto a silica extraction column. The column was washed with deionized water and then eluted with methanol. The eluates were evaporated under nitrogen gas. The residue was reconstituted with the mobile phase and injected onto the high-performance liquid chromatographic system: a 5-micron, 25 cm X 4.6 mm I.D. ODS2 column was used with acetonitrile, tetrahydrofuran and 0.05 M phosphate buffer as the mobile phase and with ultraviolet detection at 204 nm. A limit of quantitation of 0.05 microgram/ml was found, with a coefficient of variation of 11.6% (n = 6). The linear range is between 0.05 and 20.00 micrograms/ml and gives a coefficient of determination (r2) or 0.9992. The method has been successfully applied to the bioavailability study of two commercial preparations of clindamycin phosphate injection (300 mg each) in twelve healthy adult male volunteers.

Correlation between direct binding ability of synthetic T. gondii SAG1 peptides to HLA-A2 measured by a sensor for surface plasmon resonance and antigenicity of the peptides for T. gondii-infected cell-specific CTL

Toxoplasma gondii (T. gondii) -infected B lymphoma cells present T. gondii antigens in the context of major histocompatibility complex molecules to T. gondii-specific CD8+ cytotoxic T cells (CTL). HLA-A2 molecules of T. gondii-infected human cells have been shown to be used in presenting T. gondii antigens to CD8+ CTL. SAG1, one of the major antigenic molecules of T. gondii, is an antigen for T. gondii-specific CTL, and represents a possible basis for vaccines. The direct binding of nonamer SAG1 peptides to HLA-A2 was assayed here using an automated biosensor system with a sensor for surface plasmon resonance detection. The antigenicity of synthetic SAG1 peptides to T. gondii-specific CD8+ CTL also was assayed. The present study found a high correlation between the binding ability of synthetic SAG1 peptides to HLA-A2 and the antigenicity of peptides to T. gondii-infected cell-specific CD8+ CTL.

Chronic calcifying pancreatitis in Taiwan: a multicentric study and comparison with western countries

BACKGROUND/AIMS

This study investigates the clinical features of chronic calcifying pancreatitis (CCP) in Taiwan and also the comparative differences in the disorder as it affects orientals and occidentals.

MATERIALS AND METHODS

Medical records at seven tertiary hospitals relating to patients diagnosed with CCP between 1976 and 1996 are reviewed and analyzed. Ninety patients were enrolled. Defining the calcification of the pancreas is achieved by plain film, ultrasonography, computed tomography, or histology.

RESULTS

CCP afflicts men more frequently than it does women, by a ratio of 3.5:1 (70 men and 20 women). The mean age is 45 years (male: 46 female: 41.4). For fifty-two patients (57.8%), alcohol is the major cause of the condition, while in others, the causes are non-alcoholic (idiopathic: 31; biliary: 4; hereditary: 3). Alcoholism is mainly associated with males and younger sufferers. The major complications are diabetes mellitus (53.3%), cysts or pseudocysts (21.1%), and biliary stricture or stones (20%). Pancreatic adenocarcinoma and splenic vein thrombosis were found in six and five patients, respectively. Three patients died from cancers of other than pancreatic origin (lung: 1;liver: 1;bile duct: 1). Thirty-three patients were treated surgically of which thirteen (39.4%), including one with pancreatic auto transplantation, improved. Fifty-seven patients received medical treatment but only eleven (19.3%) improved.

CONCLUSIONS

The clinical features of CCP in Taiwan are notably similar to those manifesting in western countries and in Japan. With the changes in life style and increased alcoholic consumption in Taiwan, the prevalence of CCP may increase and its demographic features may alter in the future.

Identification of the mouse calcium-binding proteins, MRP 8 and MRP 14, in Schistosoma mansoni-induced granulomas: biochemical and functional characterization

Granuloma initiation factor (GIF), which elicits a granulomatous reaction in naive murine skin, contains low-molecular-weight proteins partially purified from organized granulomas developed in livers of mice with schistosomiasis. In this study, we found that 10- and 14-kDa proteins in the GIF are highly homologous to mouse migration inhibitory factor-related protein (MRP) 8 and MRP 14. Compared with the N-terminal amino acid sequence deduced from each corresponding cDNA, the 10-kDa protein from the granuloma lacks the first methionine, whereas the 14 kDa misses methionine, alanine, and asparagine. Immunohistochemically, cells expressing MRP 8 and MRP 14 considerably increased in different murine tissues after Schistosoma mansoni infection and concentrated in liver around the dilated blood vessels and at the edge of granulomas. The staining of differentiated macrophages and epithelioid cells located in the center of the granulomas was negative. Immunoreactivity of peritoneal exudate cells also was found to gradually disappear with time in cell culture. Furthermore, in vivo effects of the recombinant proteins in murine skin were described histologically. Both MRPs caused severe infiltration of neutrophils and monocytes during 7-14 days. The reaction resulting from individual MRP implantation became minimal after 50 days but inoculation of the Ca2+-dependent heterodimers showed an extensive eosinophil accumulation.

Protein kinase C inhibits adenylyl cyclase type VI activity during desensitization of the A2a-adenosine receptor-mediated cAMP response

We have previously reported that phosphorylation of adenylyl cyclase type VI (AC6) may result in the suppression of adenylyl cyclase activity during desensitization of the A2a-adenosine receptor-mediated cAMP response (A2a desensitization) in rat pheochromocytoma PC12 cells. In the present study, we demonstrate that protein kinase C (PKC) is responsible for the phosphorylation and inhibition of AC6 during A2a desensitization. Inhibition of PKC by several independent methods markedly blocked the suppression of AC6 during A2a desensitization. Purified PKC from rat brain directly phosphorylated and inhibited recombinant AC6 expressed in Sf21 cells. Substantially lower AC6 activities were also observed in PC12 cells overexpressing PKCdelta or PKCepsilon. Stimulation of A2a-R in PC12 cells under the same conditions as those required for A2a desensitization resulted in an increase in Ca2+-independent PKC activity. Most importantly, exogenous PKC did not further suppress AC6 activity in A2a-desensitized membranes. In vitro PKC phosphorylation of AC6 isolated from A2a-desensitized cells was also profoundly lower than that from control cells, suggesting a specific role for PKC in regulating AC6 during A2a desensitization in PC12 cells. Taken together, our data demonstrate that a calcium-independent, novel PKC inhibits AC6 activity during A2a desensitization in PC12 cells. Independent regulation of AC6 by calcium-independent PKC and by Ca2+ provides an exquisite mechanism for integrating signaling pathways to fine-tune cAMP synthesis.

Heat shock cognate protein 71-associated peptides function as an epitope for Toxoplasma gondii-specific CD4+ CTL

HLA-DR-restricted CD4+ cytotoxic T-lymphocyte (CTL) lines specific for Toxoplasma gondii (T. gondii)-infected melanoma cells have been established from peripheral blood lymphocytes (PBLs) of a patient with chronic toxoplasmosis. The role of heat shock cognate protein (HSC) 71 in antigen (Ag) processing and presentation of T. gondii-infected melanoma cells to these CD4+ CTL lines was investigated. A human melanoma cell line (P36) pulsed with T. gondii-infected P36 cell-derived HSC71 was lysed by a T. gondii-specific CD4+ CTL line (Tx-HSC-1). The Tx-HSC-1 also killed T. gondii-infected P36 cells. The lytic activity of Tx-HSC-1 against P36 cells pulsed with T. gondii-infected P36 cell-derived HSC71 was inhibited by monoclonal antibodies (mAbs) against HSC71. Anti-human leukocyte antigen (HLA)-DR mAb also partially blocked the lytic activity, whereas anti-HLA-A,B,C mAb did not block the lytic activity. In addition, a flow cytometric analysis with these specific mAbs against HSC71 showed HSC71 to be expressed on the cell surface of T. gondii-infected P36 cells as well as uninfected P36 cells. These data indicate that HSC71 molecules are expressed on human melanoma cell line P36, and that HSC71 may play a potential role in Ag presentation and processing of T. gondii-infected P36 cells to CD4+ CTL.

Activity of lactate dehydrogenase but not its concentration of messenger RNA increases with body size in barred sand bass, Paralabrax nebulifer (Teleostei)

In white skeletal muscle of conspecific pelagic fishes, the activity of enzymes associated with anaerobic glycolysis, e.g., lactate dehydrogenase (LDH), usually scale positively with increasing body size; this pattern is opposite to that found for enzymes of aerobic metabolism, which decrease in mass-specific activity with size (1-3). The higher mass-specific capacities for anaerobic ATP generation in larger conspecifics are thought to facilitate conservation of high-speed ("burst") swimming ability in fishes of different sizes (1). To investigate the mechanisms responsible for scaling of LDH activity, total RNA, and the specific mRNA for LDH-A (the skeletal muscle isoform of the enzyme) in white muscle of paralabrax nebulifer, the barred sand bass. We also measured total protein concentration and the concentration of actin, the major protein of thin filaments, and its specific mRNA. Although LDH activity scaled significantly with body size as predicted (1-4), no other biochemical trait measured showed a significant size-dependent concentration. We conclude that the regulation of LDH activity in white muscle of this species is not governed by LDH-A mRNA concentrations, but rather by one or more other mechanisms, for example rate of translation of LDH message or a reduced rate of degradation of LDH-A in larger fish.

Epidermoid cysts of the testis: diagnosis by ultrasonography and magnetic resonance imaging resulting in organ-preserving surgery

OBJECTIVE

To present experience in the diagnosis and management of patients with an epidermoid cyst of the testes and to confirm the role of conservative surgery.

PATIENTS AND METHODS

The records from the last 26.5 years of patients diagnosed as having a testicular tumour were reviewed retrospectively. Those patients with a confirmed epidermoid cyst were evaluated for age, clinical assessment, methods of diagnosis, treatment and follow-up.

RESULTS

Amongst a total of 131 testicular tumours, 11 patients (8.4%; mean age 25.7 years, range 21-35) were diagnosed pathologically as having an epidermoid cyst. Pre-operative suspicion of the benign nature of the lesions was supported by testicular ultrasonography in six patients and supplemented with magnetic resonance imaging (MRI) in one. An operation sparing the testicles was performed in eight patients after the diagnosis of epidermoid cyst was confirmed from frozen sections. Three patients were treated by radical orchidectomy. There were no relapses after a median follow-up of 47.3 months (range 2-82).

CONCLUSION

In this series, the relative incidence of epidermoid cyst was higher than that reported in the literature (1-2%). Ultrasonography and MRI of the testes may allow the diagnosis to be made preoperatively. The absence of relapse in these patients further supports the use of organ-sparing surgery in these young men.

Differential regulation of HLA-DR expression and antigen presentation in Toxoplasma gondii-infected melanoma cells by interleukin 6 and interferon gamma

CD4+ cytotoxic T lymphocytes (CTL) clones, YT-4 and YT-9, specific for Toxoplasma gondii (T. gondii)-infected melanoma SK-MEL 28 (P36), were generated from the peripheral blood lymphocytes (PBL) of a patient with chronic toxoplasmosis. These CTL clones were shown to secrete significant amounts of interleukin 6 (IL-6) and interferon gamma (IFN-gamma) upon antigen (Ag)-specific stimulation. Downregulation of human leukocyte antigen (HLA)-DR surface expression and HLA-DR mRNA levels in P36 cells were observed when P36 cells were infected with T. gondii. Such downregulated HLA-DR expressions of T. gondii-infected P36 cells were upregulated by treatment with both recombinant IL-6 (rIL-6) and recombinant IFN-gamma (rIFN-gamma). The antigen-presenting ability of T. gondii-infected P36 cells to T. gondii-infected cell-specific CTL was enhanced by rIFN-gamma but not by rIL-6. The present study reveals the existence of differential regulation of HLA-DR expression and Ag presentation in T. gondii-infected melanoma cells by IL-6 and IFN-gamma.

Snail-headed catheter retriever: a simple way to remove catheters from female patients

A snail-headed catheter retriever was designed to remove the Double-J* catheter from female patients. The catheter can be removed within a few minutes using topical anesthesia at the outpatient department without endoscopic instrumentation and lithotomy position. No infection or bleeding developed following the procedure and all patients tolerated it well. The cost-effective retriever can be used as a convenient alternative for Double-J catheter removal from female patients.

The expression of ferritin on renal cancers and its relationship with cellular differentiation and tumour stage

OBJECTIVES

To investigate ferritin expression in renal carcinoma and the correlation of expression with tumour differentiation and stage.

PATIENTS AND METHODS

Ferritin was immunohistologically detected in 35 patients (23 men and 12 women; mean age 58.2 years, range 40-82) with renal carcinoma and the findings compared with cellular type, tumour stage and the ferritin expression of a similar control population of 16 patients.

RESULTS

The incidence of ferritin expression in renal carcinomas was 51%. Expression was significantly related to tumour stage and not cellular type.

CONCLUSION

The results of this study re-emphasize the high expression of ferritin in renal cell carcinoma and the correlation of expression with tumour behaviour.

Enhanced cytotoxicity of IFN-gamma-producing CD4+ cytotoxic T lymphocytes specific for T. gondii-infected human melanoma cells

CD4+ lines specific for Toxoplasma gondii-infected human melanoma P36 cells were established from PBL of a patient with chronic toxoplasmosis. CD4+ CTL lines were obtained by weekly in vitro stimulation with T. gondii-infected P36 cells that shared HLA-DR4 molecules with the patient. The lytic activity of CD4+ CTL lines against T. gondii-infected P36 or T. gondii-infected autologous EBV-transformed B lymphoma (EBV-Ya) was inhibited by anti-HLA-DR mAb, whereas anti-HLA-A, B, C mAb failed to block the lytic activity. Thus, the cytotoxicity of CD4+ CTL lines against T. gondii-infected P36 was restricted by HLA-DR molecules. In response to Ag-specific stimulation, CD4+ CTL lines produced significant levels of IFN-gamma. Exogenously added IFN-gamma up-regulated the surface expression of MHC class II, but not of class I in T. gondii-infected P36 cells. In addition, the CTL activity against T. gondii-infected P36 cells was augmented when target cells were co-cultured with IFN-gamma. These data indicate that CD4+ CTL-mediated cytotoxicity against T. gondii-infected melanocytes is enhanced by the autocrine production of IFN-gamma. Further, CD4+ CTL may play a role in the manifestation of toxoplasmic retinochoroiditis by killing T. gondii-infected melanocytes.

Enhanced cytotoxicity of IFN-gamma-producing CD4+ cytotoxic T lymphocytes specific for T. gondii-infected human melanoma cells

CD4+ lines specific for Toxoplasma gondii-infected human melanoma P36 cells were established from PBL of a patient with chronic toxoplasmosis. CD4+ CTL lines were obtained by weekly in vitro stimulation with T. gondii-infected P36 cells that shared HLA-DR4 molecules with the patient. The lytic activity of CD4+ CTL lines against T. gondii-infected P36 or T. gondii-infected autologous EBV-transformed B lymphoma (EBV-Ya) was inhibited by anti-HLA-DR mAb, whereas anti-HLA-A, B, C mAb failed to block the lytic activity. Thus, the cytotoxicity of CD4+ CTL lines against T. gondii-infected P36 was restricted by HLA-DR molecules. In response to Ag-specific stimulation, CD4+ CTL lines produced significant levels of IFN-gamma. Exogenously added IFN-gamma up-regulated the surface expression of MHC class II, but not of class I in T. gondii-infected P36 cells. In addition, the CTL activity against T. gondii-infected P36 cells was augmented when target cells were co-cultured with IFN-gamma. These data indicate that CD4+ CTL-mediated cytotoxicity against T. gondii-infected melanocytes is enhanced by the autocrine production of IFN-gamma. Further, CD4+ CTL may play a role in the manifestation of toxoplasmic retinochoroiditis by killing T. gondii-infected melanocytes.

Purification and characterization of nucleolin and its identification as a transcription repressor

Expression of the acute-phase response genes, such as that for alpha-1 acid glycoprotein (AGP), involves both positive and negative transcription factors. A positive transcription factor, AGP/EBP, and a negative transcription factor, factor B, have been identified as the two most important factors responsible for the induction of the AGP gene. In this paper we report the purification, characterization, and identification of a B-motif-binding factor from the mouse hepatoma cell line 129p. The purified factor has been identified as nucleolin by amino acid sequence analysis. Biochemical and functional studies further established that nucleolin is a transcription repressor for regulation of AGP and possibly other acute-phase response genes. Thus, in addition to the many known functions of nucleolin, such as rRNA transcription, processing, ribosome biogenesis, and the shuttling of proteins between the cytoplasmic and nuclear compartments, it may also function as a transcriptional repressor.

Studies on hyperthermic solidification as a supplement to surgical resection in the treatment of 39 advanced cases of liver cancer

Localized hyperthermic solidification therapy employs a high temperature of around 65 degrees C to induce biological heat effects for the solidification and inactivation of the cells of visceral cancers without affecting the physiological processes of the body or any of the viscera. This technique was used in combination with surgical resection to treat 39 moderately or far advanced cases of liver cancer and quite satisfactory results were obtained. The FHCL-92B localized hyperthermic solidification apparatus, designed and manufactured under the supervision of the authors, was preliminarily put into clinical use and exhibited its efficiency. It is believed that, if the technique of localized hyperthermic solidification is introduced more widely into the field of cancer surgery for internal organs, it will be of benefit to prevent iatrogenic metastases and to promote the efficacy of cancer surgery.

Isolation of naturally processed peptides from a Toxoplasma gondii-infected human B lymphoma cell line that are recognized by cytotoxic T lymphocytes

Naturally processed peptides derived from Toxoplasma gondii (T. gondii) were acid extracted from T. gondii-infected cells and detected by cytotoxic T lymphocytes (CTL) derived from peripheral blood lymphocytes of a patient with chronic toxoplasmosis. The CTL lines were obtained by weekly in vitro stimulation with a T. gondii-infected human B cell lymphoma line, ARH, which shares HLA-A2 and -Cw4 determinants with the patient. The lytic activity of these CTL lines against T. gondii-infected ARH and ARH pulsed with fraction 29 of a reversed-phase high-performance liquid chromatography (HPLC) extract from T. gondii-infected ARH was inhibited by an anti-HLA-A, B, C monoclonal antibody (mAb) and an anti-HLA-A2 mAb. Anti-HLA-DR mAb failed to block the lytic activity. Thus, the presentation of peptides by T. gondii-infected cells for CTL is mediated by HLA-A2 molecules. Interestingly, antigen presentation of ARH pulsed with naturally processed HPLC fraction 29 peptides was not inhibited by treatment with brefeldin A. The amino acid sequence of the HLA-A2-bound peptide in fraction 29 was in part consistent with the predictive algorithm of HLA-A2-binding peptide motifs.

Respiratory, Blood, and Heart Enzymatic Adaptations of Sebastolobus alascanus (Scorpaenidae; Teleostei) to the Oxygen Minimum Zone: A Comparative Study

The scorpaenid fishes Sebastolobus alascanus and Scorpaena guttata have similar life styles but differ in their depth distributions: S. guttata lives in shallow water (< 180 m); adult S. alascanus occur predominantly on the upper continental slope (400-1200 m) where the oxygen minimum zone (OMZ) prevails and ambient temperature is much colder. Respiratory properties and the activities of heart-tissue enzymes of these species were compared to determine the effect of different thermal and ambient O2 regimens on metabolism. Measured over the appropriate habitat temperature ranges, the oxygen consumption (VO2) of S. alascanus is two to four times less than that of S. guttata. Correction for differences in habitat temperature accounted for over 50% of this reduction. The depth-related decrease in VO2 for these two benthic fishes is less than that observed for pelagic fishes. The VO2 of S. guttata decreases at O2 concentrations below 1 ml/l, whereas the VO2 of S. alascanus is regulated down to 0.3 ml/l. The ventilation frequency (Vf) of both species increases in progressive hypoxia; but at < 0.5 ml/l, the Vf of S. guttata declines, while that of S. alascanus does not. When measured at the same temperature, pH and CO2, the blood-O2 affinity of S. guttata is significantly lower than that of S. alascanus. The anaerobic/aerobic enzyme activity ratio of pyruvate kinase to citrate synthase, which correlates with the ability of heart tissue to tolerate hypoxia, is significantly higher for S. alascanus than S. guttata. Lactate dehydrogenase (LDH) activity in freshly collected S. alascanus is also significantly above that of specimens acclimated to normoxic water in the laboratory. Only the skeletal muscle isozyme of LDH (LDH-A) is present in the heart of S. alascanus, whereas S. guttata has both LDH-A and heart (LDH-B) isozymes. Data for metabolic rate, critical O2 tension, blood oxygen affinity, and heart metabolic enzyme profiles all show essential adaptations of S. alascanus for life in the OMZ.

The conformation of echinomycin in DMSO solution

The conformation of the antibiotic echinomycin in DMSO solution has been determined from two-dimensional NMR and distance geometry calculation with distance constraints. Five converged conformations were calculated with NOE distance constraints followed by restraint energy minimization.

Cytotoxic principles of Securinega virosa: virosecurinine and viroallosecurinine and related derivatives

Virosecurinine (1) and viroallosecurinine (2) were isolated as two cytotoxic alkaloids from the leaves of Securinega virosa. A comparison of the cytotoxicity of 1 and several of its derivatives indicates that an alpha,beta- and a gamma,delta-unsaturated lactone located in a strained ring system, such as rings -B, -C, and -D of 1, is structurally required for significant cytotoxicity.

Small cell carcinoma of the urinary tract

Small cell carcinomas of the urinary tract are rare, but lethal. We report 3 cases of primary small cell carcinoma of the kidney, urinary bladder and prostate with light microscopic, immunohistochemical and electron microscopic findings. One patient with small cell carcinoma of the prostate died of disseminated disease 2 years after diagnosis and another patient with small cell carcinoma of the urinary bladder was free of tumour after 6 months. A partial remission was induced in the third patient with distant metastases of small cell carcinoma of the kidney by using chemotherapy protocols similar to the drug regimens for small cell carcinomas of the lung; the patient survived for 5 months. Immunohistochemical studies revealed the absence of argyrophilic immunostaining of tumour cells in all 3 cases, positive staining for keratin in 2 and staining for neuron-specific enolase in all 3. In the third patient, reactivity for prostate-specific antigen was negative. Dense-core, membrane-bound granules were identified in the cytoplasm of 2 patients. The paraneoplastic syndrome was not found, indicating that in considering the occurrence of ectopic hormones, specific cytoplasmic granules of origin need not be implicated. Recognition of this distinct entity requires full consideration of morphological, immunohistological, ultrastructural and biological features. In order to define the origin of this tumour more clearly and to evaluate the effectiveness of chemotherapy, larger series of patients are needed.