Altered Th1/Th2 balance associated with the immunosuppressive/protective effect of the H-2Ab allele on the response to allo-4-hydroxyphenylpyruvate dioxygenase

The H-2Ab allele exerts a dominant down-regulatory effect on the anti-allo-HPPD (4-hydroxyphenylpyruvate dioxygenase) antibody response, through a hitherto unknown mechanism. In the present study, the allo-variable peptide bound to responder H-2Ak molecules with higher affinity than to H-2Ab ones, arguing against the operation of an affinity hierarchy. Quantitative polymerase chain reaction revealed differences in cytokine mRNA expression between suppressed and high-responder mice. Lymph node cells of responder but not suppressed mice contained high levels of interleukin (IL)-4 mRNA as early as 11 h post-immunization and continued to do so for at least 8 days; this early burst was paralleled by a small burst in transforming growth factor (TGF)-beta mRNA level. Differences in IL-12 mRNA were not detected, although an early IL-12 effect could not be excluded. Interferon (IFN)-gamma appeared to contribute to the suppression at later time points. Early treatment of responder mice with anti-IL-4 monoclonal antibody (11B11) down-regulated the antibody response. The proliferative T cell response from hyperimmunized mice was reduced but still detectable in the presence of an H-2Ab allele. Thus, in the presence of this allele, the Th1 response is enhanced and that of Th2 cells suppressed, apparently as a result of the bias of H-2Ab-restricted T cells in favor of the Th1 subset.

Condensation pressure during amalgam placement in patients

The purpose of this study was to investigate the condensation pressure during amalgam placement in patients. Forty-four practitioners were asked to fill two class 2 cavities in the lower jaw on their patients in their own practice with the aid of a force-measuring plugger. This device, with semiconductor strain gauges, allowed the dentist to have an identical tactile feedback as with any other plugger. Three different amalgams, with different shapes of alloy particles, were tested. The results showed a maximum condensation pressure of 8.9+/-2.4 MPa and 5.5+/-1.8 MPa with a small and a large amalgam plugger, respectively. Average condensation pressures were 3.7+/-1.3 MPa for the small and 2.2+/-0.9 MPa for the large instrument. The total working time required to fill a cavity was on average 131 s; the amalgam was effectively condensed for 44 s. No significant differences between amalgams with different shapes of alloy particles, no influence of time of day, and no difference between female and male dentists were found. This study showed that the condensation pressure is lower than often recommended, and that it is not statistically different from the values obtained in a previous laboratory study.

Clinical evaluation of different doses of intravenous enalaprilat in patients with hypertensive crises

BACKGROUND

The appropriate dose of intravenous enalaprilat to be used in the treatment of hypertensive crisis is controversial. There has been no comparative study of the efficacy and safety of different dosages of enalaprilat in hypertensive patients.

METHODS

Sixty-five consecutive patients with hypertensive urgencies (systolic blood pressure > 210 mm Hg and/or diastolic blood pressure > 110 mm Hg) or emergencies (diastolic blood pressure > 100 mm Hg and evidence of end-organ damage, ie, angina pectoris, hypertensive encephalopathy, or congestive heart failure) admitted to an emergency department from January 1, 1994, to September 30, 1994, were identified. The patients were randomized to receive different doses of enalaprilat (0.625, 1.25, 2.5, and 5 mg). Response to treatment was defined as a stable reduction of systolic blood pressure to below 180 mm Hg and diastolic blood pressure to below 95 mm Hg within 45 minutes after the start of treatment and relief of symptoms in patients with hypertensive emergencies.

RESULTS

In 41 (63%) of 65 patients, the treatment goal was reached. Twenty-four patients (37%) failed to achieve the goal of treatment within 45 minutes after administration of enalaprilat. The response rates in the 0.625-mg, 1.25-mg, 2.5-mg, and 5-mg groups were 67%, 65%, 59%, and 62%, respectively. The proportion of patients initially randomized who responded to treatment was not different between any of the four groups of enalaprilat doses. There were no significant differences according to enalaprilat dose with respect to changes in systolic, diastolic, and mean arterial blood pressure. No severe side effects were observed.

CONCLUSION

Enalaprilat is a safe antihypertensive drug with moderate efficacy in the treatment of hypertensive crisis. As doses above 0.625 mg alter neither response rates nor the magnitude of blood pressure reduction, we recommend 0.625 mg as the initial dose in the treatment of hypertensive crisis.

Clinical application of volume estimation based on three-dimensional ultrasonography

The development of three-dimensional sonography represents a milestone in the history of diagnostic ultrasound. It has become possible to evaluate a region of interest not only in the horizontal and vertical planes but also in a third, i.e. the frontal, plane. Among other possible applications, this technique greatly facilitates volume estimation. The objective of the present study was to evaluate the accuracy and precision of volumetry based on three-dimensional sonography. The results demonstrate a good correlation between estimated volumes and the volumes measured by transvaginal needle-guided follicle aspiration performed under sonographic visualization. Our findings confirm the conclusion of previous studies that three-dimensional sonography is making a valuable contribution to imaging techniques.

Identification of axons in the peri-implant region by immunohistochemistry

In the edentulous patient with a completely implant-supported prosthesis, periodontal ligament receptors are absent. However, the implant patient's mandibular function during mastication and clenching is significantly improved and can be similar to that of dentulous subjects. The underlying mechanisms that govern this proprioceptive control are not well understood. One possibility that has been explored only partially is that residual axonal elements in the peri-implant region may have a proprioceptive function. To survey the peri-implant region for axonal elements, this study utilized immunohistochemistry with neurofilament as the marker. Histologic sections of the peri-implant area from 12 implants placed in the mandibles of three dogs were examined for the presence of neurofilament. Two to three labeled sites per section in the peri-implant region were commonly found. However, the functional significance of these axons must be further evaluated before any conclusions regarding their role in proprioception can be made.

Evaluation of the reliability of 6 current anti-HIV-1/HIV-2 enzyme immunoassays

The sensitivity for early detection of HIV antibodies and specificity of 6 anti-HIV-1/HIV-2 screening enzyme immunoassays (ELISAs) currently on the market were investigated by testing a panel of 249 well-characterized serum samples. The panel included sera from AIDS patients or children with congenital HIV infection, high-risk individuals and patients with conditions unrelated to AIDS. 'Tricky' sera (repeatedly positive results by ELISA and negative or indeterminate results by Western blot; n = 69) were also used in this evaluation along with 6 seroconversion panels. One second-generation assay (Biotest) and two third-generation assays (Abbott and Murex) showed the highest sensitivity for early detection of HIV-1 antibodies in seroconversion panels. A high specificity was achieved with the Cambridge Biotech (100%) and Ortho ELISA (99.4%). A relatively high rate of false-positive results was obtained with the Biotest (n = 10) and the Pasteur assays (n = 8) by testing 'tricky' sera and samples from high-risk individuals and from patients with other acute viral infections. In conclusion, it remains difficult to combine high specificity with an accurate detection of early seroconversion for anti-HIV-1/HIV-2 screening enzyme immunoassays.

Spectrophotometric determination of ascorbic acid and dehydroascorbic acid

We present a method for measuring ascorbic acid in methanol/trichloroacetic acid extracts prepared from human plasma after enzymatic oxidation of ascorbic acid to dehydroascorbic acid by ascorbate oxidase. Samples were assayed by spectrophotometrically monitoring the kinetics of the concentration-dependent absorbance changes of dehydroascorbic acid with phosphate-citrate-methanol buffers. Ascorbic acid was determined as the difference between dehydroascorbic acid and total ascorbic acid content. The detection limit was < 0.5 mumol/L. The calibration curve was linear (r > 0.995) over the range 0-1000 mumol/L. Analytical recovery of ascorbic acid added to plasma was 93-105%. The between-day variance was < 7%. Comparison of the spectrophotometric determination (y) with a chromatographic procedure (x) gave y = 1.02x - 0.653 (Sylx = 3.61) over the range of physiologically relevant concentrations. Total analysis time is < 10 min per sample and allows the simultaneous analysis of multiple samples.

Cutaneous bacillary angiomatosis in a patient with chronic lymphocytic leukemia

BACKGROUND

Bacillary angiomatosis is a recently described vascular disorder that is associated with infection by Bartonella henselae (formerly known as Rochalimaea henselae) and Bartonella quintana (formerly known as Rochalimaea quintana); this disorder usually occurs in patients with human immunodeficiency virus infection. We report a case of cutaneous bacillary angiomatosis that occurred in a patient with chronic lymphocytic leukemia.

OBSERVATIONS

A 55-year-old man with chronic lymphocytic B-cell leukemia, Rai stage IV, presented with multiple angiomatous papules that clinically resembled pyogenic granulomas. Histopathologic examination revealed circumscribed lobules of small vessels with plump endothelial cells, numerous neutrophils, and abundant nuclear dust; these features were diagnostic for bacillary angiomatosis. The diagnosis was confirmed by the Grocott-Gomori methenamine-silver nitrate stain that revealed argyrophilic bacteria and by ultrastructural demonstration of bacillary structures with trilaminar walls. Treatment with clarithromycin led to complete resolution of the lesions within 4 weeks.

CONCLUSIONS

This case emphasizes that (1) bacillary angiomatosis must be considered in the differential diagnosis of vascular lesions in immunocompromised patients without human immunodeficiency virus infection, (2) Grocott-Gomori methenamine-silver nitrate stain is a simple and satisfactory alternative to the Warthin-Starry stain for the demonstration of bacilli in this condition, and (3) clarithromycin is an effective oral antibiotic for the treatment of this disease.

Congenital agminated segmental naevi

We report a 39-year-old woman with agminated segmental naevi on the right side of her face. The lesions were present at birth, and she had no other congenital abnormalities.

Spectrophotometric determination of ascorbic acid and dehydroascorbic acid

We present a method for measuring ascorbic acid in methanol/trichloroacetic acid extracts prepared from human plasma after enzymatic oxidation of ascorbic acid to dehydroascorbic acid by ascorbate oxidase. Samples were assayed by spectrophotometrically monitoring the kinetics of the concentration-dependent absorbance changes of dehydroascorbic acid with phosphate-citrate-methanol buffers. Ascorbic acid was determined as the difference between dehydroascorbic acid and total ascorbic acid content. The detection limit was &lt; 0.5 mumol/L. The calibration curve was linear (r &gt; 0.995) over the range 0-1000 mumol/L. Analytical recovery of ascorbic acid added to plasma was 93-105%. The between-day variance was &lt; 7%. Comparison of the spectrophotometric determination (y) with a chromatographic procedure (x) gave y = 1.02x - 0.653 (Sylx = 3.61) over the range of physiologically relevant concentrations. Total analysis time is &lt; 10 min per sample and allows the simultaneous analysis of multiple samples.

[Successful outcome of "intracytoplasmic sperm injection" (ICSI) within the scope of in vitro fertilization]

Poor function of spermatozoa accounts for half of all human infertility. "Intracytoplasmic sperm injection" (ICSI) is a new micromanipulatory method for the treatment of male infertility. "ICSI" was performed in cases of oligoasthenozoospermia in 12 IVF cycles, obtaining a fertilisation rate of 71.2% of all micromanipulated oocytes. So far four ongoing pregnancies occurred. Thus "Intracytoplasmic sperm Injection" represents a new encouraging technique to conceive, even in cases of severe male infertility.

The MIM complex mediates preprotein translocation across the mitochondrial inner membrane and couples it to the mt-Hsp70/ATP driving system

We have identified a complex in mitochondria that functions as a part of the preprotein import machinery of the inner membrane (MIM complex). Two known components, MIM23 and MIM17, and two novel components, MIM33 and MIM14, were found as constituents of this complex. In the presence of a translocating chain, the outer membrane import machinery (MOM complex) and the MIM complex form translocation contact sites. On the matrix side, the MIM complex is associated with the mt-Hsp70-MIM44 system. We propose a structure of the import machinery in which the MIM complex constitutes a proteinaceous channel that accepts preproteins from the MOM complex, facilitates their reversible transmembrane movement, and mediates unidirectional transport by linkage to the ATP-dependent mt-Hsp70-MIM44 system.

Echocardiography for teaching cardiac physiology in practical student courses

We have introduced echocardiography into the physiology courses for medical students to improve their understanding of cardiac physiology. Echocardiography allows a visualization of the events of the cardiac cycle and facilitates the correlation of anatomic structures with their physiological functions. The students record views on the human heart in the long and short axis, they follow wall and value motions, and they interpret the obtained data in correlation with electrocardiography and phonocardiography. Echocardiography offers the opportunity to measure the interval of isovolumetric contraction and isovolumetric relaxation and permits the calculation of parameters assigned to left ventricular contractility. An evaluation showed that medical students consider echocardiography to be the most significant and interesting part of the physiology courses. In conclusion, echocardiography has been shown to be a valuable tool for teaching cardiac physiology.

Follow-up of patients with inverted papilloma of the nasal cavities: computer tomography, video-endoscopy, acoustic rhinometry?

Seventeen patients were operated suffering from unilateral inverted papilloma of the nasal cavities, in one male associated with malignancy. We investigated these patients pre- and post-operatively by clinical examination, video-endoscopy, acoustic rhinometry, and computed tomography (CT). The aim was to find out which technique delivers reliable information about tumour recurrence in follow-up. By these controls three recurrences could be detected in a period of two-years' follow-up. Our results showed that the combination of CT, video-endoscopy and histological examination of biopsies is reliable to detect recurrence of inverted papilloma. To study the possibilities of detecting tumour recurrence by means of acoustic rhinometry, investigations on models of nasal cavities with various shape, size and location of tumour masses were undertaken. A comparison between the results of the model study and the acoustic rhinometric measurements in patients showed that growth of tumour masses can be detected by this method in an early phase under constant conditions such as nasal models. In patients, however, it is not easy to evaluate the absolute size and site of the growing tumour masses, because there are several factors which lead to false-positive interpretations, such as localized inflammations of the mucosa, crusting and nasal secretion and especially the movements of the soft palate. We conclude from our results that acoustic rhinometry does not deliver more information than obtained by video-endoscopy and CT to detect tumour recurrence in the nasal cavity.

Mitochondrial Hsp70/MIM44 complex facilitates protein import

Protein translocation into mitochondria requires the mitochondrial protein Hsp70. This molecular chaperone of the mitochondrial matrix is recruited to the protein import machinery by MIM44, a component associated with the inner membrane of the mitochondria. Formation of the mt-Hsp70/MIM44 complex is regulated by ATP. MIM44 and mt-Hsp 70 interact in a sequential manner with incoming segments of unfolded preproteins and thereby facilitate stepwise vectorial translocation of proteins across the mitochondrial membranes. The complex appears to act as a molecular ratchet which is energetically driven by the hydrolysis of ATP.

Spectrophotometric determination of dehydroascorbic acid in biological samples

We describe a method for accurately and precisely measuring dehydroascorbic acid in perchloric acid extracts prepared from human plasma, lymphocytes, and mammalian cells. Samples were assayed by spectrophotometrically monitoring the kinetics of the concentration-dependent absorbance changes of dehydroascorbic acid with phosphate-methanol-containing buffers. The lowest detectable dehydroascorbate concentration using this assay is estimated to be below 0.1 mumol/liter. Total analysis time is less than 10 min and allows the simultaneous measurement of numerous samples. The calibration curve is linear (r > 0.995) over the range 0-200 mumol/liter. The dehydroascorbic acid concentrations measured in supplemented samples agree with known concentrations. Interference of ascorbic acid and 2,3-diketogulonic acid with this assay was excluded. The correlation with a highly specific chromatographic procedure gave comparable results over the range of physiologically relevant concentrations. The procedure avoids the most commonly applied method of measuring the native ascorbic acid, then reducing the dehydroascorbic acid, and finally measuring the total ascorbic acid and determining dehydroascorbic acid by the difference. Stabilization of ascorbic acid during assay was achieved by addition of desferrioxamine.

N-ethylmaleimide-sensitive fusion protein: a trimeric ATPase whose hydrolysis of ATP is required for membrane fusion

The NEM-sensitive fusion protein, NSF, together with SNAPs (soluble NSF attachment proteins) and the SNAREs (SNAP receptors), is thought to be generally used for the fusion of transport vesicles to their target membranes. NSF is a homotrimer whose polypeptide subunits are made up of three distinct domains: an amino-terminal domain (N) and two homologous ATP-binding domains (D1 and D2). Mutants of NSF were produced in which either the order or composition of the three domains were altered. These mutants could not support intra-Golgi transport, but they indicated that the D2 domain was required for trimerization of the NSF subunits. Mutations of the first ATP-binding site that affected either the binding (K266A) or hydrolysis (E329Q) of ATP completely eliminated NSF activity. The hydrolysis mutant was an effective, reversible inhibitor of Golgi transport with an IC50 of 125 ng/50 microliters assay. Mutants in the second ATP-binding site (binding, K549A; hydrolysis, D604Q) had either 14 or 42% the specific activity of the wild-type protein, respectively. Using coexpression of an inactive mutant with wild-type subunits, it was possible to produce a recombinant form of trimeric NSF that contained a mixture of subunits. The mixed NSF trimers were inactive, even when only one mutant subunit was present, suggesting that NSF action requires each of the three subunits in a concerted mechanism. These studies demonstrate that the ability of the D1 domain to hydrolyze ATP is required for NSF activity and, therefore is required for membrane fusion. The D2 domain is required for trimerization, but its ability to hydrolyze ATP is not absolutely required for NSF function.

[Video-feedback therapy with the flexible nasopharyngoscope. The potentials for modifying velopharyngeal closure and phonation deficiencies in cleft patients]

Psychological interviews with cleft palate patients have revealed why a number of these patients do not profit, or do so only on a limited basis, from conventional speech therapy. They don't control articulation by means of the auditory canal. To treat these patients the video feedback therapy with the nasopharyngoscopy (Witzel et al.) was employed as the initial step. The next step was to expand on this method by establishing indication criteria, necessary diagnostic techniques, and an efficient therapy plan. In this paper a single case study is employed to discuss this method and show the results attained by its use.

Early and specific antibody response to OspA in Lyme Disease

Borrelia burgdorferi (Bb), the cause of Lyme disease, has appeared not to evoke a detectable specific antibody response in humans until long after infection. This delayed response has been a biologic puzzle and has hampered early diagnosis. Antibody to the abundant organism-specific outer surface proteins, such as the 31-kD OspA, has rarely been detected less than 6 mo after infection. Antibody to a less organism-specific 41-kD flagellin protein, sharing common determinants with other bacteria and thus limiting its diagnostic potential, may appear after 4 to 6 wks. To investigate our hypothesis that specific antibody to OspA may actually be formed early but remain at low levels or bound in immune complexes, we analyzed serum samples from patients with concurrent erythema migrans (EM). This is the earliest sign of Lyme disease and occurs in 60-70% of patients, generally 4-14 d after infection. We used less conventional but more sensitive methods: biotin-avidin Western blots and immune complex dissociation techniques. Antibody specificity was confirmed with recombinant OspA. Specific complexed antibody to whole Bb and recombinant OspA was detected in 10 of 11 of the EM patients compared to 0 of 20 endemic area controls. IgM was the predominant isotype to OspA in these EM patients. Free IgM to OspA was found in half the EM cases. IgM to OspA was also detected in 10 of 10 European patients with EM who also had reactive T cells to recombinant OspA. In conclusion a specific antibody response to OspA occurs early in Lyme disease. This is likely to have diagnostic implications.

Efficient but aberrant cleavage of mitochondrial precursor proteins by the chloroplast stromal processing peptidase

Cytosol-synthesized chloroplast and mitochondrial precursor proteins are proteolytically processed after import by highly specific, metal-dependent soluble enzymes: the stromal processing peptidase (SPP) and the matrix processing peptidase (MPP), respectively. We have used in vitro processing assays to compare the reaction specificities of highly purified preparations of pea SPP and Neurospora crassa MPP, both of which are unable to cleave a variety of 'foreign' proteins. We show that SPP can cleave all five mitochondrial precursor proteins tested, namely cyclophilin, the beta subunit of the F1-ATPase complex, the Rieske FeS protein, the alpha-MPP subunit and cytochrome b2. In contrast, MPP is unable to cleave any chloroplast precursor proteins tested. Several of the mitochondrial precursor proteins are cleaved more efficiently by SPP than are many authentic chloroplast precursor proteins but, in each case, cleavage takes place at a site or sites which are N-terminal to the authentic MPP site; pre-cyclophilin is cleaved 5 residues upstream of the MPP site and the precursor of the beta subunit of the F1-ATPase complex is cleaved at sites 5 and 12 residues upstream. We discuss the implications of these data for the SPP reaction mechanism.

Characterization of the mitochondrial processing peptidase of Neurospora crassa

The mitochondrial processing peptidase (MPP) of Neurospora crassa is constituted by an alpha- and a beta-subunit. We have purified alpha-MPP after expression in Escherichia coli while beta-MPP was purified from mitochondria. A fusion protein between precytochrome b2 and mouse dihydrofolate reductase was expressed in E. coli, and the purified protein was used as substrate for MPP. Both subunits of MPP are required for processing. MPP removes the matrix targeting signal of cytochrome b2 by a single cut, and the resulting presequence peptide is 31 amino acid residues in length. It acts as a competitive inhibitor of processing but has a approximately 30-fold lower affinity for MPP than the preprotein. Competition assays show that MPP recognizes the COOH-terminal portion of the presequence of cytochrome b2 rather than the NH2-terminal part which has the potential to form an amphiphilic helix. Substitution of arginine in position -2 of the matrix targeting sequence of cytochrome b2 prevents processing but not import of a chimeric precursor. Substitution of the tyrosyl residue in position +1 also prevents processing, indicating that MPP interacts with sequences COOH-terminal to the cleavage site. Non-cleavable preprotein is still recognized by MPP. Our data suggest that processing peptidase and import machinery recognize distinct structural elements in preproteins which, however, can be overlapping.

Use of pregnancy-specific protein-B and estrone sulfate for determination of pregnancy on Day 49 in fallow deer ()

The objective of this study was to determine if pregnancy specific protein-B (PSPB) and estrone sulfate (E(1)SO(4)) could be used to determine pregnancy status in fallow deer (Dama dama ). Forty mature does were synchronized for estrus with an intravaginal progesterone-releasing device (CIDR) and then artificially inseminated via laparoscopy with frozen semen on one day. Ultrasound examination and jugular blood sampling were done 49 days later. Transrectal ultrasonography was done to presumptively determine the pregnancy status at the time of blood sampling. Serum estrone sulfate concentrations were significantly (P < 0.05) greater in pregnant (n=31) than nonpregnant (n=9) females at 49 days of gestation (166.7 +/- 25.9 pg/ml vs 36.3 +/- 11.1 pg/ml, respectively). The percentage of [(125)I]PSPB bound was significantly (P < 0.01) lower when sera of pregnant (n=29) versus nonpregnant (n=9) females was added to RIA tubes (63.7 +/- 1.6% vs 98.1 +/- 1.6%, respectively). There were 30 fawns born from the group of females that were diagnosed pregnant based on ultrasound. We conclude that estrone sulfate and PSPB can be used to determine pregnancy status in fallow deer at 49 days of gestation.

SNAP receptors implicated in vesicle targeting and fusion

The N-ethylmaleimide-sensitive fusion protein (NSF) and the soluble NSF attachment proteins (SNAPs) appear to be essential components of the intracellular membrane fusion apparatus. An affinity purification procedure based on the natural binding of these proteins to their targets was used to isolate SNAP receptors (SNAREs) from bovine brain. Remarkably, the four principal proteins isolated were all proteins associated with the synapse, with one type located in the synaptic vesicle and another in the plasma membrane, suggesting a simple mechanism for vesicle docking. The existence of numerous SNARE-related proteins, each apparently specific for a single kind of vesicle or target membrane, indicates that NSF and SNAPs may be universal components of a vesicle fusion apparatus common to both constitutive and regulated fusion (including neurotransmitter release), in which the SNAREs may help to ensure vesicle-to-target specificity.

SNAP family of NSF attachment proteins includes a brain-specific isoform

The soluble NSF attachment proteins (SNAPs) enable N-ethyl-maleimide-sensitive fusion protein (NSF) to bind to target membranes. Here we report the cloning and sequencing of complementary DNAs encoding alpha-, beta- and gamma-SNAPs. Two of these proteins, alpha and gamma, are found in a wide range of tissues, and act synergistically in intra-Golgi transport. The third, beta, is a brain-specific isoform of alpha-SNAP. Thus, NSF and SNAPs appear to be general components of the intracellular membrane fusion apparatus, and their action at specific sites of fusion must be controlled by SNAP receptors particular to the membranes being fused, as described in the accompanying article.

Domain structure of an N-ethylmaleimide-sensitive fusion protein involved in vesicular transport

N-Ethylmaleimide-sensitive fusion protein (NSF) is an essential component for protein transport between Golgi cisternae. Sequence analysis and proteolytic dissection reveal that NSF contains two tandem "ATP domains," each containing the consensus sequence for the binding of nucleotide. When Escherichia coli-produced Chinese hamster ovary NSF is purified, it exhibits a low, but significant, ATPase activity. The ATPase activity of NSF is sensitive to N-ethylmaleimide and influenced by monoclonal antibodies against recombinant NSF.

Analysis of the six additional chemicals for in vitro assays of the European Economic Communities' EEC aneuploidy programme using Saccharomyces cerevisiae D61.M and the in vitro porcine brain tubulin assembly assay

We tested six additional chemicals (acetaldehyde, benomyl, diethylstilboestrol, diethylstilboestrol dipropionate, griseofulvin, and mercaptoethanol) for in vitro systems of the coordinated programme to study aneuploidy induction sponsored by the Commission of the European Communities in two in vitro test systems. Using Saccharomyces cerevisiae D61.M (mitotic chromosomal malsegregation assay), benomyl showed a dose-dependent increase in the frequency of chromosomal malsegregation with a lowest effective dose tested (LEDT) of 30 micrograms/ml (0.1 mM). Diethylstilboestrol (DES) showed solvent-dependent effects. DES dissolved in ethanol induced an increase in chromosomal malsegregation as well as in the frequency of total resistant colonies (mutations and recombinations) with a LEDT around 13 micrograms/ml (0.048 mM). Using dimethylsulfoxide as the solvent, no increases were observed with DES up to 333 micrograms/ml (1.24 mM). Acetaldehyde induced an increase in chromosomal malsegregation with the cold treatment protocol (LEDT: 1.25 microliters/ml (21 mM) and 0.75 microliters/ml (13 mM), respectively) but no increase with the overnight protocol (highest dose tested (HDT): 1.75 microliters/ml; 30 mM). Concerning the frequency of total cycloheximide-resistant colonies (mutations and recombinations) increases were obtained with both protocols. The other three compounds were negative when tested up to toxic doses (survival below 10%), up to the maximum solubility in the solvent used or up to heavy precipitation in the incubation mix. The HDT were 333 micrograms/ml (0.88 mM) for diethylstilboestrol dipropionate, 1,600 micrograms/ml (4.5 mM) for griseofulvin and 0.5 microliters/ml (7 mM) for mercaptoethanol. Concerning effects on porcine brain tubulin assembly in vitro, diethylstilboestrol and griseofulvin inhibited the assembly process. The IC30% (30% inhibition concentration) values were 12.5 microM and 100 microM for DES and griseofulvin, respectively. Mercaptoethanol showed no effects up to 50 mM.

[Acoustic rhinometry: the bat principle of the nose]

All cross-sectional areas of the upper airway can be measured by an acoustic signal using the acoustic reflection technique, or acoustic rhinometry. The plane of the cross-sectional areas measured was determined in nasal models. The isotemporal layers were found to be nearly parallel to the nasal valve. The acoustically measured cross-sectional areas correlated with the cross-sectional areas of cuts from nasal models. After digitizing these cuts, a CAD software calculates cross-sectional areas in all orientations and at all distances. The difference between the measured and calculated cross-sectional areas is up to 3% in the nasal cavity and up to 17% in the nasopharynx. The hypothesis that the cross-sectional areas measured lie nearly parallel to the nasal valve was confirmed. The normal rhinometric curve shows the minimal cross-sectional area (I-notch) to lie at the nasal isthmus. The second narrowest segment of the nasal cavity lies at the head of the inferior concha and septal concha (C-notch). Characteristic examples of patients with turbinate hypertrophy, choanal atresia, enlarged adenoids, and septal deviations are presented. Acoustic rhinometric curves can only be interpreted in combination with the rhinoscopic findings because different pathological conditions can produce similar curves. Recording of reliable and reproducible data by acoustic rhinometry demands that the connection between the rhinometer and the nose does not distort the valve area. When we used two different nose pieces (1.2 and 1.5 cm outer diameter) the cross-sectional areas in the anterior third of the nose of only 28% of the patients was measured correctly.(ABSTRACT TRUNCATED AT 250 WORDS)

Soluble N-ethylmaleimide-sensitive fusion attachment proteins (SNAPs) bind to a multi-SNAP receptor complex in Golgi membranes

Soluble N-ethylmaleimide-sensitive fusion attachment proteins (SNAPs) are required for the binding of N-ethylmaleimide-sensitive fusion protein (NSF) to Golgi membranes and are, therefore, required for intra-Golgi transport. We report the existence of distinct alpha/beta-SNAP and gamma-SNAP-binding sites in Golgi membranes that appear to be part of the same receptor complex. Cross-linking studies with alpha-SNAP demonstrate that an integral membrane protein of between 30-40 kDa is the alpha-SNAP binding component of the multi-SNAP receptor complex. These data suggest that SNAPs function by independently binding to a multi-SNAP membrane-receptor complex, thereby activating them to serve as adaptors for the targeting of NSF.

Cellular changes in rat parathyroids provoked by progesterone and testosterone

Male rats kept on a standard diet were treated either with progesterone or testosterone by a single intramuscular injection of preparations which are slowly absorbed and metabolized. The rats were anaesthetized 24 h after application of the hormones, perfused with glutaraldehyde, and the parathyroid glands prepared for electron microscopy. Morphometric analysis revealed that both progesterone and testosterone provoked (1) an increment in nuclear and cell volume and a concomitant increment in cell surface area, and (2) an increment in surface area of rough endoplasmic reticulum by 42% and 49%, and of the Golgi complex by 85% and 63%, respectively. Previously, we had found that oestradiol treatment led to a similar response in parathyroid cells. The conclusion is thus drawn that male and female sex hormones induce membrane synthesis resulting in an enhanced capacity for parathyroid hormone secretion since RER and Golgi complex are concerned with this secretion. It is considered probable that sex hormones have the ability fundamentally to modulate secretory activity in parathyroid cells.

A multisubunit particle implicated in membrane fusion

The N-ethylmaleimide sensitive fusion protein (NSF) is required for fusion of lipid bilayers at many locations within eukaryotic cells. Binding of NSF to Golgi membranes is known to require an integral membrane receptor and one or more members of a family of related soluble NSF attachment proteins (alpha-, beta-, and gamma-SNAPs). Here we demonstrate the direct interaction of NSF, SNAPs and an integral membrane component in a detergent solubilized system. We show that NSF only binds to SNAPs in the presence of the integral receptor, resulting in the formation of a multisubunit protein complex with a sedimentation coefficient of 20S. Particle assembly reveals striking differences between members of the SNAP protein family; gamma-SNAP associates with the complex via a binding site distinct from that used by alpha- and beta-SNAPs, which are themselves equivalent, alternative subunits of the particle. Once formed, the 20S particle is subsequently able to disassemble in a process coupled to the hydrolysis of ATP. We suggest how cycles of complex assembly and disassembly could help confer specificity to the generalized NSF-dependent fusion apparatus.

ADP-ribosylation factor is a subunit of the coat of Golgi-derived COP-coated vesicles: a novel role for a GTP-binding protein

ADP-ribosylation factor (ARF) is an abundant and highly conserved low molecular weight GTP-binding protein that was originally identified as a key element required for the action of cholera toxin in mammalian cells, but whose physiological role is unknown. We report that ARF family proteins are highly concentrated in non-clathrin-coated transport vesicles and are coat proteins. About three copies of ARF are present on the outside of coated vesicles per alpha-COP (and thus per coatomer). ARF is highly enriched in coated vesicles as compared with parental Golgi cisternae, as shown both by biochemical and morphological methods, and ARF is removed from transport vesicles through uncoating during transport. Furthermore, ARF binds to Golgi cisternae in a GTP-dependent manner independently of coated vesicle budding. These observations strongly suggest a new role for GTP-binding proteins: ARF proteins may modulate vesicle budding and uncoating through controlled GTP hydrolysis.

A new cuff electrode for reversible conduction blocking

A cuff electrode of novel design (rigid body and lid) is presented. It contains a closed cavity surrounding the nerve, through which a cooled liquid (Ringer solution) can be circulated. Recording sites at both ends of the cavity permit monitoring of the conduction blocking, which occurs at different temperatures for different units. Reversible blocking with chemical agents is equally possible with this device.

Effects of 10 known or suspected spindle poisons in the in vitro porcine brain tubulin assembly assay

We tested the 10 known or suspected spindle poisons (colchicine, econazole nitrate, chloral hydrate, hydroquinone, diazepam, thiabendazole, cadmium chloride, thimerosal, pyrimethamine and vinblastine) of the coordinated EEC programme for induction of aneuploidy with the in vitro porcine brain tubulin assembly assay. The influence of the compounds on different parameters [lag-phase, polymerization velocity, endabsorption (steady-state level), reversibility, influence on disassembly at 4 degrees C] was evaluated. Colchicine [IC30 (30% inhibition concentration): 0.002 mM), vinblastine (IC30: 0.002 mM), thimerosal (IC30: 0.03 mM), thiabendazole (IC30: 0.5 mM) and chloral hydrate (IC30: 60 mM) led to an inhibition of tubulin assembly in vitro. No influence on the steady-state level was obtained with econazole nitrate (up to 0.1 mM), diazepam (up to 2.5 mM), cadmium chloride (up to 1 mM), pyrimethamine (up to 1 mM) and hydroquinone (up to 25 mM), the highest dose tested being limited either by precipitation or by reaching the maximal solubility of the compound in the solvent used. Diazepam enhanced the lag-phase and slightly reduced the polymerization velocity dose-dependently; however, all the treated test mixtures reached the same end absorption levels as the control. The influence on the disassembly process was studied at 4 degrees C. Microtubules treated with colchicine, econazole nitrate, diazepam, thiabendazole, cadmium chloride, thimerosal and pyrimethamine reached the same end absorption level after disassembly as the untreated control. Chloral hydrate reduced the disassembly rate but the end absorption of the control was not reached, the 30% reduction concentration being 0.25 mM. Hydroquinone at very high doses (greater than 10 mM) stimulated the disassembly process.(ABSTRACT TRUNCATED AT 250 WORDS)

A precision multichannel cuff electrode optimized by simulation and experiment

The parameters influencing single end and differential en passant extracellular recordings were investigated using two independent simulation methods. The results were compared with measurements from experimental electrodes. The effects of electrode size, electrode distance and leakage can thus be understood and the experiments agree with the simulation results. This led to the optimation of a novel en passant electrode producing very narrow signals with very high reliability. The electrode is used for multichannel recording in a velocity selective recording system.

Intrauterine insemination of farmed fallow deer () with frozen-thawed semen via laparoscopy

Estrus and ovulation of mature fallow does (n=155) on two North American farms were synchronized by intravaginal silastic devices containing 0.3 g progesterone (CIDR-type G) for 14 d. Each of 151 does received laparoscopic intrauterine inseminations of either 50x10(6) (n=125) or 25x10(6) (n=26) frozen-thawed spermatozoa, 65 to 68 h after CIDR device withdrawal. Four does received intrauterine inseminations per vaginam of 50x10(6) spermatozoa 68 to 69 hours after CIDR device withdrawal. Semen from crossbred Dama dama damaxDama dama mesopotamica sires was collected in New Zealand by electroejaculation. The overall pregnancy rate to artificial insemination, as assessed by rectal ultrasonography at Day 45, was 67.7%. The pregnancy rates for does receiving laparoscopic inseminations were 58.2% (Texas; 50x10(6) spermatozoa; n=79 does); 80.8% (Texas; 25x10(6) spermatozoa; n=26 does) and 76.1% (New York; 50x10(6) spermatozoa; n=46 does). Three of the four does receiving intrauterine inseminations per vaginam became pregnant to the frozen-thawed semen.

An improved system for single unit isolation from multiunit nerve recordings by velocity analysis

A system for recording and decomposition of complex extracellular spike trains by analog computing is presented. Unlike other systems, it is not necessary to establish templates for the analysis. Rather by adjustments of a single knob, the velocity band can be adjusted. The velocity measurement can be made to a precision of better than 1%, where the velocity jitter in individual spikes of a unit becomes apparent. Spike trains on the connective of a stick insect are analyzed which occur during an intersegmental reflex, the CLP reflex.

Absence of BK virus sequences in transformed hamster cells transfected by human tumor DNA

In an attempt to gain insight into the mechanism of oncogenic transformation by BK virus (BKV), a human papovavirus, we have probed for BKV sequences in transformed hamster cells in which oncogenic transformation had occurred as a result of transfection by human tumor DNA positive for BKV sequences. Even though the sources of the transfecting DNA contained BKV sequences, the transformed hamster cells which arose from the transfection for the most part did not retain BKV sequences. In only one barely detectable case was BKV-specific DNA found associated with chromosomal DNA, and in only a small minority of the transformed cells was BKV DNA detected in the Hirt supernatant, indicating an episomal configuration. Even in these few cases where BKV sequences were present in an episomal form, altered migration on gels of some BKV-positive bands (compared to bands derived from cloned viral DNA) suggested deletions and rearrangements of BKV DNA. We employed several different probe methodologies for these studies, including nick-translation, random primer and a non-isotopic biotinylated probe which gave a sensitivity that could detect better than 0.01 copy of viral genome per diploid cell. We conclude that transformation by transfection with human tumor DNA does not require persistence of the BKV viral genome, suggesting that either BKV virus was irrelevant to original oncogenesis, in analogy with models proposed by others for herpesvirus oncogenesis.