Role for T cell-independent B cell activity in the resolution of primary rotavirus infection in mice.

We examined the importance of T cell-independent B cell activity in the resolution of primary murine (EDIM) rotavirus infection in adult mice. We showed that Rag 1 (C57BL / 6 background) and Rag 2 (BALB / c background) knockout mice, which lack both T and B cells, chronically shed high levels of rotavirus Ag in stool samples following oral inoculation. However, nude mice (BALB / c and C57BL / 6 backgrounds) and alpha beta TCR knockout mice (C57BL / 6 background) chronically shed 100-fold lower levels of virus in stool samples. Thus, B cells appeared to sharply reduce the level of chronic rotavirus shedding by a T cell-independent mechanism. C57BL / 6 mice depleted of CD4(+) cells or both CD4(+) and CD8(+) cells were also unable to resolve primary rotavirus infection but chronically shed equally low levels of rotavirus Ag in stool samples, whereas mice depleted of only CD8(+) cells resolved infection. Similar results were obtained with a second rotavirus strain (EC(w)) in which virus was shed chronically in stool samples at low levels in alpha beta TCR knockout mice and at high levels in Rag 1 knockout mice. Virus-specific intestinal IgA was readily detected in mice lacking thymic T cells and alpha beta T cells and in mice depleted of CD4(+) cells but levels were 95 % reduced in comparison to immunocompetent control mice. Together, these results show that B cells lacking CD4(+) T cell help have the capacity to substantially reduce rotavirus shedding, possibly through the production of T cell-independent IgA to rotavirus, but full resolution requires alpha beta T cells.

Taste reactivity and consumption measures in the assessment of overshadowing: Modulation of aversive, but not ingestive, reactivity.

Three dependent measures-a taste reactivity test, a two-bottle preference test, and a one-bottle extinction test-were used to investigate the conditioning effects of pairing a taste/taste compound with LiCl-induced illness in rats. Avoidance of saccharin consumption in the one-bottle test was attenuated if saccharin and denatonium were paired during illness training (overshadowing). Also, saccharin was found to be more palatable if paired with denatonium during training as reflected by aversive (but not ingestive) taste reactivity measures. It is argued that overshadowing was reflected mainly by a modulation of aversive taste reactivity behavior with little influence on ingestive taste reactivity. The results are discussed in terms of current palatability issues, and it is suggested that applying taste reactivity tests to phenomena associated with taste avoidance learning (e.g., overshadowing or potentiation) may further our understanding of the mechanisms that guide such learning.

Instrumented laparoscopic spinal fusion. Preliminary Results.

STUDY DESIGN: Seventeen consecutive patients underwent laparoscopic instrumented interbody fusions using custom-designed delivery instrumentation and "BAK" fusion cages; both are manufactured by Spinetech and the former was developed by the authors. The cases were performed at two spine centers under Food and Drug Administration investigational device evaluation clinical trials. OBJECTIVES: We expect this approach will maintain a high fusion rate with diminished hospitalization time, recovery time, patient discomfort, and expense. The rehabilitative aspects of the procedure are a great improvement over traditional fusion approaches. SUMMARY AND BACKGROUND DATA: Extraordinary advances in many endoscopic surgical fields have resulted in many endoscopic surgical fields have resulted in lowered morbidity, expense, and suffering associated with their open surgery counterparts. The authors have developed prototype of delivery instruments for the current laparoscopic fusion cage delivery system. METHODS: The procedure is performed transperitoneally with carbon dioxide insufflation to enable video-assisted visualization through a 10-mm endoscope. Three 10-mm incisions and one 13- to 20-mm incision are required for one-level procedures. Two hollow titanium-threaded interbody implants are packed with autologous bone and inserted into the diseased interspace. RESULTS: Seventeen patients, with an average follow-up period of 8 months and a range of 6-12 months, underwent the procedure. There were 14 single-level fusions and three two-level fusions, all involving L4-S1 levels. There were two cases that required conversion to open procedures without sequelae; two patients had remote donor site wound infections eradicated with incision and drainage and antibiotics, and one patient required subsequent posterior spinal decompression because of a displaced endplate fracture. Average hospital stay was an average of 2 days, excluding two patients with complications and very prolonged stay. CONCLUSIONS: Although this procedure is associated with a long learning curve, the technique, once mastered, is effective and advantageous over current approaches to lumbar fusion. Operative time and hospital stay are expected to decrease with future instrumentation development and surgeon experience.

Characterization of Tru-Trax in-vitro penetration testing of cervical mucus.

To determine the distribution of results of an in-vitro cervical mucus penetration system employing both human and bovine mucus (Tru-Trax) in a general infertility population, 133 couples prospectively underwent in-vitro and post-coital testing of cervical mucus. The distribution of Tru-Trax results in couples with normal semen analyses and Insler scores showed significantly greater penetration in bovine (22.3 +/- 6.0 mm) than in human mucus (20.3 +/- 5.4 mm) (P < 0.001). However, the lower limit of the 95% confidence interval of the normal population with either type of mucus was approximately 10 mm. This limit was significantly lower than that described by the kit manufacturer. The predictive value for post-coital tests using human mucus in the Tru-Trax system was good (> 90%) in all groups. The overall penetration into either human or bovine mucus was significantly correlated with the percentage of motile spermatozoa in the semen sample (P < 0.001). In conclusion, in-vitro cervical mucus penetration tests with the Tru-Trax system are related to in-vivo post-coital tests, although the lower limit of the range of anticipated results in the normal population was significantly lower than that described by the manufacturer. The ultimate value of this type of testing will await clinical trials which evaluate clinical end-points such as pregnancy rates.

Binding of actinomycin D to the T(G)nT motif of double-stranded DNA: determination of the guanine requirement in nonclassical, non-GpC binding sites.

Strong binding of the antitumor antibiotic actinomycin D to the sequence 5'-TGGGT-3' in double-stranded DNA was recently established by equilibrium binding studies (Bailey et al., 1993). Actinomycin D binding to this -TGGGT- containing sequence was shown to be comparable to that of an -XGCY- containing oligonucleotide (Ka approximately 10(6) M-1). Investigation of -TGGGT- as a high-affinity binding site for actinomycin D follows from our 1989 sequencing study (Rill et al., 1989) in which the photoaffinity analog of actinomycin D (7-azidoactinomycin D) was used to determine DNA base sequence specificities and neighboring base effects. The studies presented here examine the guanine requirements for actinomycin D binding to such nonclassical (non-dGpC) sites by varying the number of central guanine residues in a series of selected duplex oligonucleotides. The central -T(G)nT- motif varies from n equals 1 to 4. Actinomycin D binding to each of these undecamers is characterized and correlated with binding to oligonucleotides of identical length and similar sequences that contain classical dGpC binding sites. Binding affinities of actinomycin D to this series of oligonucleotide duplexes (10 degrees C) can be summarized as -TGGGT- > -TGGT- > TGGGGT- > -TGT. The kinetics of SDS-induced dissociation of actinomycin D from these oligonucleotides reveal single-exponential decays with duration dependent on the sequence at the binding site. With the exception of the -TGGGT- containing oligomer, dissociation times for the T(G)nT duplexes were drastically different and much shorter than times obtained for the dissociation of actinomycin D from oligonucleotides having classical dGpC sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of leuprolide acetate and human chorionic gonadotropin for the induction of ovulation in clomiphene citrate-stimulated cycles.

OBJECTIVE: To examine the relative efficacies of leuprolide acetate (LA) and hCG in inducing ovulation and a normal luteal phase during clomiphene citrate (CC)-stimulated superovulation cycles. DESIGN: Prospective, randomized, blinded, and cross-controlled in consecutive cycles. SETTING: Large military tertiary care center. PATIENTS: Twenty-one ovulatory patients undergoing superovulation with CC and IUIs for the treatment of unexplained or male factor infertility. INTERVENTIONS: Clomiphene citrate (100 mg/d) on cycle days 5 through 9 in both of the study cycles. Administration of 2 mg SC LA in one cycle and 10,000 IU IM hCG in another cycle for induction of the midcycle surge. MAIN OUTCOME MEASURES: Serum LH, FSH, E2, and P levels every 12 hours for 36 hours after administration of either LA or hCG to characterize the midcycle hormonal dynamics. Luteal phase duration and serum P levels during the midluteal phase were used to estimate the adequacy of the luteal phase. Serial ultrasounds also were done to determine the incidence of luteinized unruptured follicle syndrome. RESULTS: Serum FSH levels in the periovulatory interval were significantly higher after the administration of LA. There were no differences in the periovulatory E2 or P levels or the incidence of sonographic evidence of ovulation after administration of either LA or hCG. Although midluteal serum P levels were higher in the cycles in which hCG was administered, all 42 treatment cycles had adequate luteal phases as assessed by luteal phase duration and three midluteal P levels. Ongoing pregnancies occurred after both LA- and hCG-stimulated cycles. CONCLUSION: Leuprolide acetate and hCG were equivalent in their abilities to induce ovulation. Further evaluation of the adequacy of the luteal phase and the ensuing pregnancy rates after LA induction of an endogenous gonadotropin surge are indicated.

Influence of DNA base sequence on the binding energetics of actinomycin D.

The influences of base sequence on the thermodynamic properties associated with the interaction of actinomycin D with DNA are examined. It has been previously established that GpC steps of double-helical DNAs are highly preferred binding sites for actinomycin D. In this study, a series of oligonucleotides was designed and synthesized to probe the effects of flanking base sequence (adjacent to the GpC step) and novel non-GpC binding sites on the binding of actinomycin D. The use of these oligonucleotides provides a direct method for quantitating sequence specificities and actinomycin D binding energetics. Effects of different 5' and 3' flanking nucleotides on the interactions of actinomycin with the core GpC binding sites were examined using UV-visible spectrophotometric methods, and changes in binding energetics were quantitated. These studies demonstrate strong actinomycin D binding affinities to both classical GpC and an atypical non-GpC site. Enthalpy and entropy components of the DNA binding energetics for the GpC binding sites are compared and correlated with those determined for actinomycin D binding to the high-affinity non-GpC site of an 11-mer containing TGGGT as the central sequence. This TGGGT site, first suggested to be a high-affinity sequence in our earlier photoaffinity labeling studies, exhibits binding of actinomycin D comparable in strength to that of traditional actinomycin D binding sites (i.e., GpC steps). From these studies, the overall affinity and specific thermodynamic contributions (delta H degree, delta S degree) to binding of actinomycin D are demonstrated to be highly influenced both by the sequence at the intercalation site and by neighboring bases which flank the intercalation site.

Evaluating cervical cone biopsy specimens with frozen sections at hysterectomy.

Frozen section evaluations of cervical cone biopsy specimens were performed at the time of hysterectomy to exclude invasive cervical cancer. During a two-year period we prospectively evaluated 43 cone biopsy specimens. We found all the diagnoses made with frozen sections to be accurate when compared with prospective permanent sections, and all patients received appropriate therapy. Thirty-eight cases showed no evidence of invasion. Two patients had invasive squamous cell cervical cancer, one had invasive cervical adenocarcinoma extending to the endometrial cavity, and two had microinvasion. All invasive cancers were diagnosed correctly with frozen sections and confirmed with permanent sections. When hysterectomy immediately followed conization, no complications occurred, and no significant increase in blood loss was noted. We found frozen section evaluation of a cone biopsy specimen at the time of hysterectomy to be a reliable procedure that saves time, eliminates the risk of additional anesthesia and decreases patients' costs.

Guillotine amputation in the treatment of nonsalvageable lower-extremity infections.

Primary definitive amputation performed in the presence of distal-extremity infection carries the risk of wound infection and additional limb loss. We reviewed 75 below-knee amputations performed for nonsalvageable foot infections. Patients were retrospectively divided into two groups: group 1 underwent open ankle guillotine amputation followed by definitive below-knee amputation, and group 2 underwent primary definitive below-knee amputation. In group 1, 97% of patients achieved primary healing after revision, and none required amputation at a higher level. In group 2, 78% of patients achieved primary healing, but 11% required revision of the amputation to the above-knee level. These data supported the following conclusion: guillotine ankle amputation followed by below-knee amputation for the nonsalvageable, infected lower extremity is associated with a significantly lower amputation failure rate than primary definitive amputation.