Putative anticryptosporidial agents tested with an immunodeficient mouse model

Lasalocid, sinefungin, and dehydroepiandrosterone were tested for anticryptosporidial activity with an immunodeficient mouse model at doses that have been reported effective when tested with immunosuppressed rodent models. Small but significant reductions in oocyst excretion were only observed under some conditions with lasalocid and dehydroepiandrosterone, but sinefungin had no effect.

[Repair of soft tissue defects of hand with pudendo-femoral skin flaps]

Soft tissue defects of the hand have been repaired with free pudendo-femoral skin flaps in 13 patients. The results are quite satisfactory in all cases. The flaps are thin with little fat to interfere with post-operative appearance. The donor sites are well-hidden and can be primarily closed with no functional disturbances. Hence the ideal donor site for soft tissue defects of the hand.

Sensitive and specific polymerase chain reaction assays for detection of Bordetella pertussis in nasopharyngeal specimens

Polymerase chain reaction (PCR) assays that amplify segments of a repeated gene element and a toxin promoter gene of Bordetella pertussis were compared with a culture established for the diagnosis of pertussis. Of 44 nasopharyngeal (NP) aspirates collected during a pertussis outbreak, repeated gene element PCR showed a positive result in 21 (48%), including all three patients with positive culture results. Results of toxin promoter gene PCR were positive in eight (18%) cases, and the pathogen was not detected in one patient with a positive culture result. A more sensitive nested PCR assay, based on repeated gene element PCR, was then developed. During a second outbreak two different transportation systems were tested in 146 duplicate NP swabs. Transportation of swabs in empty tubes proved to be better than in transport media for PCR. A total of 190 NP specimens from the two outbreaks were tested, and in 56 the results were shown to be positive by PCR, including all 16 cases confirmed as positive by culture. We conclude that the PCR assay is more sensitive than culture in the diagnosis of pertussis; NP swabbing is a simple, practical, and reliable method of collecting clinical specimens for PCR assays and cultures.

[Chondrolaryngoplasty]

We have successfully performed chondrolaryngoplasty in 6 cases. The results are satisfactory. Of the patients, five have previously undergone male to female transsexual operation and one with pseudohermaphroditism. Chondrolaryngoplasty is performed under local anesthesia. The amount of excised thyroid cartilage is 2.0 to 2.4 cm in length and 0.6 to 1.2 cm in width on each side. In 3 cases, mild hoarseness is observed postoperatively and it is very transient, lasting less than 20 days. This paper introduces the applied anatomy, operative technique and key points for a successful chondrolaryngoplasty.

Inhibition of the spore polar filament extrusion of the microsporidium, Encephalitozoon hellem, isolated from an AIDS patient

Spores of the microsporidian parasitic protozoan Encephalitozoon hellem were purified and incubated at 37 degrees C in a solution with an electrolyte composition similar to that of mammalian extracellular fluid, and in solution in which the calcium had been replaced with 0.2 mM EGTA. Polar filament extrusion (germination) was monitored by both scanning electron microscopy and light microscopy. Germination was pH-dependent, with optima at pH 7.4 and 9.5, and was significantly greater in the presence of medium calcium. Hydrogen peroxide caused a concentration-dependent increase in germination that was also reduced in a calcium-free medium. Four agents were found to inhibit spontaneous and H2O2-stimulated polar filament extrusion: the microfilament disrupter, cytochalasin D; the microtubule disrupter, demecolcine; the calcium channel blocker, nifedipine; and the antifungal agent, itraconazole. These results are consistent with the existence of a calcium-channel-mediated step, and requirements for an F-actin- and for a tubulin-containing element in the germination process of the spore of this parasite. Nifedipine, cytochalasin D and itraconazole all have different sites of action and were therefore able to potentiate one another when used in paired combination to inhibit germination.

Possible network interactions indicated by bilaterally coherent fast rhythms in expiratory recurrent laryngeal nerve discharges

1. In a search for correlated fast rhythms in recurrent laryngeal (RL) expiratory (E) activities, we performed spectral and coherence analysis on bilateral RL nerve discharges in 54 midcollicular decerebrate, paralyzed cats. 2. Inspiratory (I) RL activities showed in almost all cases high-frequency oscillations (HFO, range 50-100 Hz) that were bilaterally coherent and also coherent to HFOs in phrenic (PHR) activities. In contrast, bilaterally coherent rhythms (range 24-54 Hz) in RLE discharges were found in only a fraction of the cats (6/54); in the other cats (48/54) such coherences were absent even though the auto-spectra showed the presence of similar fast rhythms on the two sides. The bilateral RLE coherences were associated with increased amplitude and prolonged duration of RLE activity, such as occurred following removal of phasic pulmonary stretch receptor inputs by vagotomy or by no-inflation. 3. Thus, although coherent fast rhythms are uncommon in RLE discharges, their occurrence under some conditions indicates the presence of short-time-scale interactions between neurons involved in this activity. This suggests that such rhythms are a general feature of neural networks.

Hepatic fibrosis and gene expression changes induced by praziquantel treatment during immune modulation of Schistosoma japonicum infection

In the present study fibrogenic gene expression was determined in murine Schistosoma japonicum infection during the progression of immune modulation of infection and following chemotherapy during the course of immune modulation. Histomorphometric analysis of granuloma size and collagen deposition revealed peak granuloma size in acute infection (5 weeks) and peak hepatic collagen content at 16 weeks of infection. Peak Type I collagen gene expression was concomitant with TGF-beta 1 gene expression at 8-11 weeks. Chemotherapy during either acute (9 weeks) or chronic (24, 28 weeks) infection resulted in increased collagen deposition and increased gene expression of Type I collagen and TGF-beta 1. However, chemotherapy at 14-16 weeks resulted in decreased levels of TGF-beta 1 gene expression and essentially minimal change in Type I collagen deposition and gene expression. These data indicate that chemotherapy of schistosomiasis japonica does not reverse hepatic fibrogenesis when administered in acute infection-when granuloma size is maximal-or in chronic infection. However, a beneficial effect on hepatic fibrogenesis is seen when chemotherapy is administered at 14-16 weeks post-infection, a time of decreasing granuloma size and maximal hepatic collagen content. Thus the ability to reverse schistosomal-induced hepatic fibrogenesis by chemotherapy may depend on disease stage.

Effects of protein malnutrition on experimental giardiasis in the Mongolian gerbil

To determine the effects of protein malnutrition on the severity and duration of infection with Giardia lamblia, Mongolian gerbils were pair-fed a pelleted control (C) diet (20% protein) and a low-protein (5%; LP) diet for 3 weeks before and after being infected with 100,000 cysts orally. Weight loss, fecal fat, enteropooling, and the duration of cyst excretion were all greater in the infected LP than in the infected C animals. During peak infection the upper intestinal intraepithelial lymphocyte infiltration, crypt enlargement, and villus enterocyte migration were greater in C than in LP animals, as was the villus mast cell number at the end of the infection. It is concluded that in the protein-malnourished host the increased severity of Giardia infection correlates with a reduction in enterocyte production and migration, probably secondary to a reduced lymphocyte infiltration, and the increased infection duration correlates with blunted mast cell migration into affected villi.

Evaluation of pooled and individual components of Bordetella pertussis as antigens in an enzyme immunoassay for diagnosis of pertussis

Six different antigen preparations for use in an enzyme immunoassay (EIA) to detect IgM, IgA and IgG antibodies to Bordetella pertussis were evaluated using sera from 13 randomly selected culture-positive patients and from 87 patients with suspected pertussis during a pertussis outbreak. Based on results in 80 healthy control sera a specificity limit of 99.9% was selected. Sera from all culture-positive patients reacted with at least one of the antigens. The sensitivity of the EIA using the individual antigen preparations was 85% for filamentous hemagglutinin, 92% for pertussis toxin, 62% for 69 kDa outer membrane protein, 85% for a pool of these three antigens, 54% for sonicated whole bacteria and 69% for 21 kDa pertussis toxin subunit S1. In the outbreak patient group 49 (56%) of the initial sera reacted with at least one of five antigen preparations. The EIA using sonicated bacteria detected only 41% of all seropositive cases compared with 51% using filamentous hemagglutinin, 61% using pertussis toxin, 65% using 69 kDa OMP and 65% using pooled antigen. It is concluded that either the pooled antigen or pertussis toxin antigen are suitable antigen preparations for use in the EIA for diagnosis of pertussis.

Comparison of polymerase chain reaction with culture and enzyme immunoassay for diagnosis of pertussis

A polymerase chain reaction (PCR) assay amplifying a segment of a repeated gene element of Bordetella pertussis was compared with culture and enzyme immunoassay (EIA) for the diagnosis of pertussis. The PCR assay was specific for B. pertussis in tests with a panel of other bacteria and with an extensive collection of specimen material from healthy persons and children with respiratory infections other than pertussis. The PCR assay was used in the analysis of 117 nasopharyngeal swabs collected from children at an elementary school at which a pertussis outbreak occurred. Fifty-six (48%) of the 117 swabs were positive, including those for all six culture-positive cases. The PCR method was then applied to analyze another pertussis outbreak. Of 40 nasopharyngeal aspirates taken from 37 clinically susceptible pertussis patients and from three asymptomatic contacts, the PCR identified 18 (45%), including all 3 culture-positive and 5 (35%) of the 14 seropositive patients. The most consistent and reliable diagnosis by positive PCR result was observed with those patients experiencing symptoms within 1 to 6 weeks of sample collection. We conclude that PCR is a rapid, sensitive, and specific means of diagnosing pertussis, especially during the first weeks of disease. The assay can be performed with both nasopharyngeal swabs and aspirates.

Molecular isoforms of murine CD44 and evidence that the membrane proximal domain is not critical for hyaluronate recognition

We previously found that the CD44 glycoprotein on some lymphocytes can mediate adhesion to hyaluronate (HA) bearing cells. However, many questions remain about the molecular heterogeneity of CD44 and mechanisms which control its recognition of this ligand. In vitro mutagenesis and DNA sequencing have now been used to investigate the importance of the membrane proximal region of murine CD44 for recognition of soluble or cell surface HA. CD44 with an 83 amino acid deletion in this region mediated binding to soluble ligand and the apparent avidity increased markedly in the presence of a particular antibody to CD44, IRAWB14. The shortened CD44 was however inefficient in mediating adhesion of transfected cells to HA immobilized on cell surfaces. Four new murine isoforms of CD44 were isolated from a carcinoma line by use of the polymerase chain reaction. Only two of them correspond to ones recently discovered in rat and human cells. The longest variant nearly doubled the length of the extracellular portion of the molecule and introduced an additional 20 potential sites for glycosylation. When expressed on T lymphoma cells, all four of the new murine CD44 isoforms were capable of mediating adhesion to HA bearing cells. This result contrasts with a report that a related human CD44 isoform lacks this ability when expressed on B lineage lymphoma cells. The new murine isoforms also conferred the ability to recognize soluble HA and were very responsive to the IRAWB14 antibody. A brief survey of normal murine cell lines and tissues revealed that the hemopoietic isoform was the most abundant species. These findings indicate that the NH2-terminal portion of CD44 is sufficient for HA recognition and that this function is not necessarily abrogated by variations which occur in the membrane proximal domain. They add to the known molecular diversity of CD44 and provide another experimental model in which isoform specific functions can be investigated.

Determination of carcinogenic potency of alkytoxynol-741 (AP-741) by rat peritoneal cell cultures

The carcinogenic potency of AP-741 was tested in rats using the Nashed method of rat peritoneal cell short-term carcinogenic test. N-methyl-N-nitro-N'-nitrosoguanidian (MNNG) was used as positive control; saline and nonoxynol-9 (NP-9) were used as negative control. Two doses of AP-741 (4 mg/kg and 40 mg/kg equivalent to 4 and 40 times human doses) were tested. The result showed that no colonies of more than 9 cells were seen in the saline and NP-9 groups, and the two dose groups of AP-741. However, 12 +/- 8.3 colonies (9-29 cell/colony) and 4.5 +/- 4.2 colonies (30-300 cell/colony) were seen in the MNNG group. According to the Nashed criterion, we can say MNNG has potential carcinogenesis, while AP-741 does not have any potential carcinogenesis and its use as a vaginal contraceptive drug is safe.

Physiologic comparison and validation of Stairobic stepping with bench stepping

To compare the oxygen cost of submaximal exercise on the Stairobic stepping (SS) machine with bench stepping (BS), 12 healthy men and women (mean age 23 years) underwent six different five minute exercise bouts that were randomly assigned. Tests were conducted using standard open circuit calorimetry. SS at 40 and 60 st/min was equal to BS at 20 st/min and SS at 80 st/min was equal to BS at 30 st/min for VE and RER. VO2 was equal at 20 st/min (BS) and 60 st/min (SS), and 30 st/min (BS) and 80 st/min (SS). Stairobic MET (SM) displayed values over-estimated actual MET (AM) values at the two lowest SS rates and under-estimated the AM value at the highest SS rate. Forty-eight observations of the MET response of SS were conducted and analyzed (BMDP2R) in a forward stepping solution. The multiple regression equation calculated for AM was: AM = -0.567 + -0.012 (WT) + 0.063 (rate) + 0.612 (SM) with an adjusted R2 of 0.82 and a SEE of 0.90. The physiologic cost of BS was approximately equal to SS at two to three times the BS rate of stepping.

Determination of trace amounts of estriol and estradiol by adsorptive cathodic stripping voltammetry

Estriol and estradiol are electroinactive in the potential range from -200 to -1000 mV versus a silver-silver chloride electrode at a mercury electrode. The conversion of these estrogens into electroactive nitro derivatives of estrogens, which are used for voltammetric determination, was studied. Such nitro derivatives give a well defined cathodic stripping wave at -600 mV in pH 10.5 borate buffer. Estriol and estradiol are determined in the ranges 1 x 10(-9)-1.5 x 10(-6) and 5 x 10(-9)-2 x 10(-6) mol dm-3, respectively, by differential-pulse adsorptive stripping voltammetry at a hanging mercury drop electrode. Some steroids, such as estrone, interfere because the three estrogens have almost the same molecular structure and have similar nitro derivatives, but progesterone does not interfere and is reduced at significantly more negative potentials than the nitrated estrogens. It can be determined simultaneously with estriol or estradiol. A method was developed for the assay of estriol in pharmaceutical preparations.

Effect of hyperthermia on thymidine salvage as related to DNA synthesis

The effect of increasing temperature up to 43 degrees C on thymidine (TdR) salvage, i.e. uptake of TdR, thymidine kinase (TK) activity, intracellular amount of thymidinetriphosphate (dTTP) and specific activity of 3H-dTTP and incorporation of dTTP into DNA, was studied in ascites tumour cells in vitro. While the uptake of [3H]TdR was almost unchanged up to 40.5 degrees C and 2.4 h followed by a decrease at later times and higher temperatures, TK activity declined already after 30 min in a temperature-dependent way, leading to a decrease in cellular amount of dTTP reaching almost undetectable values at 43 degrees C and 6.0 h. The specific activity of [3H]dTTP in the cell was elevated at 39 degrees C and 43 degrees C, but somewhat reduced at 40.5 degrees C. Incorporation into DNA of [3H]TdR decreased in a temperature-dependent way with increasing incubation time. After correction for specific activity of [3H]dTTP, however, the incorporation of [3H]TdR into DNA at 39 degrees C and 40.5 degrees C was unchanged up to 2.4 h and for 40.5 degrees C up to 6.0 h, while incorporation into DNA at 43 degrees C was still reduced. The overall protein synthesis was also reduced in a temperature-dependent way. We concluded that phosphorylation of TdR to dTMP was more sensitive to moderately elevated temperatures than uptake of TdR and DNA synthesis per se, caused by a reduced TK activity. The decline in TK activity was probably due to a decrease in TK polypeptide synthesis.

Requirements for hyaluronic acid binding by CD44: a role for the cytoplasmic domain and activation by antibody

The CD44-negative T lymphoma AKR1 (CD44.2 genotype) was transfected with a CD44.1 cDNA. The intact cDNA conferred on the transfected cells the ability to bind hyaluronic acid (HA) both from solution and immobilized on culture plates. It also conferred a CD44-dependent and hyaluronidase-sensitive increase in adhesion to a lymph node endothelial cell line. A mutant cDNA which codes for a CD44 molecule lacking most of the cytoplasmic domain of CD44 was also transfected into AKR1, and cell sorting was used to select transfectants expressing levels of cell surface CD44 expression comparable with the line transfected with the wild-type CD44 cDNA. The cells transfected with the mutant construct bound fluoresceinated HA from solution very poorly, but did adhere to immobilized HA, though less well than cells transfected with the wild-type construct. This result indicates that the cytoplasmic domain of CD44 is necessary for binding of HA from solution but is not required for binding to immobilized HA, although it may contribute to adhesion following ligand recognition. A monoclonal antibody (mAb), IRAWB 14, which reacts with CD44 on all CD44+ cells dramatically induced HA binding by some CD44+ cell lines that did not constitutively bind HA. The transfectant expressing a CD44 molecule with a truncated cytoplasmic domain could be induced by this antibody to bind fluoresceinated-HA from solution. Splenic T cells did not bind fluoresceinated HA constitutively. In the presence of the IRAWB 14 mAb, virtually all CD44+ splenic T cells bound HA. Induction was immediate and occurred equally well at room temperature and at 4 degrees C, indicating that the new HA-binding activity was due to preexistent CD44 molecules. These results are compatible with an antibody-induced activation of CD44 by either a conformational change in the CD44 molecule or a change in the distribution of CD44 molecules on the cell surface.

Cell cycle related studies on thymidine kinase and its isoenzymes in Ehrlich ascites tumours

Thymidine kinase (TK) activity was measured in relation to the cell cycle of in vivo growing ascites tumour cells. The cells were synchronized by means of centrifugal elutriation and the cell cycle composition of the cell fractions was determined by flow cytometry. TK activity was low in G1, increased during S phase and declined in G2. A half-life of TK activity of about 45 min was found throughout the cell cycle. Four isoenzymes at pI values of 4.1, 5.3, 6.9 and 8.3, denoted as isoenzymes 1-4, were identified using isoelectric focusing. Isoenzymes 3 and 4 were responsible for the profound cell cycle related changes in the TK activity. Corresponding isoenzymes were also found in the fetal mouse liver. In the adult mouse liver isoenzyme 2 was the dominating isoenzyme. The half-life of the isoenzymes was in the same range as for the total TK activity. We conclude that the low TK activity in G1 is due to degradation of the enzyme in G2 at a normal rate combined with an arrest in the synthesis of TK. We also conclude that isoenzyme 4 and the intermediate isoenzyme 3, which had earlier been suggested to be a mitochondrial form of TK, in fact represent cytoplasmatic forms of TK. According to cell cycle and pI studies, isoenzyme 2 belongs to the mitochondrial form. Studies with various phosphor donors and specific substrates, however, indicate that it also contains a cytoplasmic component.

Lack of correlation between thymidine kinase activity and changes of DNA synthesis with tumour age: an in vivo study in Ehrlich ascites tumour

Thymidine kinase (TK) and its isoenzymes were studied in relation to age of Ehrlich ascites tumour cells growing in vivo. Various steps of the pathway of thymidine through deoxynucleotide metabolism were studied: [3H]-thymidine cellular uptake and incorporation into DNA; the cellular nucleotide pools; and the concentration of thymidine in ascites. In addition, the proportion of cells in the various parts of the cell cycle and the bromodeoxyuridine labelling index were determined. Four isoenzymes at pI 4.1, 5.3, 6.9 and 8.3 were identified using isoelectric focusing. The TK activity declined with age of the tumour by about 90%, mostly due to a decrease of the isoenzyme at pI 8.3. However, this decline was neither related to the changes in DNA synthesis rate of the cells with tumour age, nor to the proportion of cells in S-phase or the bromodeoxyuridine (BrdU) labelling index. In contrast, the contribution of DNA synthesis via the thymidine salvage pathway relative to the total DNA synthesis increased from less than 1% at exponential growth to about 15% at plateau phase of growth. Blocking of DNA synthesis by aphidicolin did not change the TK activity. We therefore conclude that changes in TK activity and changes in cell growth are epiphenomena rather than causally related to each other. All nucleotide pools decreased with tumour age. The inhibition of TK by an increase in the deoxythymidine triphosphate pool could therefore be excluded. With a decrease of the TK activity during tumour growth, increasing amounts of TdR were excreted by the cells and accumulated in the ascites fluid. To explain our results on TK activity we propose a substrate cycle in which thymidine monophosphate supplied by de novo synthesis is dephosphorylated and is then either phosphorylated by TK to thymidine monophosphate or excreted by the cell.

Nd:MgO:LiNbO(3) waveguide laser and amplifier

We report efficient operation of a channel waveguide laser and a channel waveguide amplifier in Nd:MgO:LiNbO(3). For the laser a cw output power of 2.9 mW was obtained for 23.6 mW of absorbed pump power. The absorbed pump power at threshold was 1.5 mW, and a slope efficiency of 13% was achieved. For the amplifier a small-signal gain of 7.5 dB was achieved for 22 mW of coupled pump power.

Sympathetic peripheral chemoreflex is independent of expiratory output neurons in the cat

Previously we reported that activities of certain chemoreflex sensitive cervical preganglionic sympathetic nerves (PSN) were augmented by carotid chemoreceptor stimulation independently of phrenic nerve (PN) activity in the cat. To test the hypothesis that the PSN carotid chemoreflex could have been mediated by the expiratory neuron activity, we studied the relationship between PSN, internal intercostal expiratory nerve (IICEN) and PN activities in vagotomized, anesthetized, paralysed and artificially ventilated cats. We made the following observations. (1) Hypoxia often inhibited IICEN activity while the PN and PSN activities were stimulated. (2) during normoxia, cyanide strongly stimulated PN and PSN discharges but only moderately IICEN discharges. (3) Hyperventilation hypocapnia suppressed or eliminated PSN and PN rhythms and activities, but made some IICEN fibers fire continuously. (4) During hypocapnic apnea, cyanide stimulated PSN activity before PN and IICEN activities, although some PSN fibers were stimulated simultaneously with PN fibers. Accordingly we conclude that IICEN activity does not significantly influence chemoreflex stimulation of PSN activity and that a direct chemoreflex stimulation of IICEN is minimal in the cat. Thus, the chemoreflex PSN response is in part independent of respiratory chemoreflex pathways.