Observation of a new superfluid phase for 3He embedded in nematically ordered aerogel.

In bulk superfluid 3He at zero magnetic field, two phases emerge with the B-phase stable everywhere except at high pressures and temperatures, where the A-phase is favoured. Aerogels with nanostructure smaller than the superfluid coherence length are the only means to introduce disorder into the superfluid. Here we use a torsion pendulum to study 3He confined in an extremely anisotropic, nematically ordered aerogel consisting of ∼10 nm-thick alumina strands, spaced by ∼100 nm, and aligned parallel to the pendulum axis. Kinks in the development of the superfluid fraction (at various pressures) as the temperature is varied correspond to phase transitions. Two such transitions are seen in the superfluid state, and we identify the superfluid phase closest to Tc at low pressure as the polar state, a phase that is not seen in bulk 3He.

Investigation of the ATP binding site of Escherichia coli aminoimidazole ribonucleotide synthetase using affinity labeling and site-directed mutagenesis.

Aminoimidazole ribonucleotide (AIR) synthetase (PurM) catalyzes the conversion of formylglycinamide ribonucleotide (FGAM) and ATP to AIR, ADP, and P(i), the fifth step in de novo purine biosynthesis. The ATP binding domain of the E. coli enzyme has been investigated using the affinity label [(14)C]-p-fluorosulfonylbenzoyl adenosine (FSBA). This compound results in time-dependent inactivation of the enzyme which is accelerated by the presence of FGAM, and gives a K(i) = 25 microM and a k(inact) = 5.6 x 10(-)(2) min(-)(1). The inactivation is inhibited by ADP and is stoichiometric with respect to AIR synthetase. After trypsin digestion of the labeled enzyme, a single labeled peptide has been isolated, I-X-G-V-V-K, where X is Lys27 modified by FSBA. Site-directed mutants of AIR synthetase were prepared in which this Lys27 was replaced with a Gln, a Leu, and an Arg and the kinetic parameters of the mutant proteins were measured. All three mutants gave k(cat)s similar to the wild-type enzyme and K(m)s for ATP less than that determined for the wild-type enzyme. Efforts to inactivate the chicken liver trifunctional AIR synthetase with FSBA were unsuccessful, despite the presence of a Lys27 equivalent. The role of Lys27 in ATP binding appears to be associated with the methylene linker rather than its epsilon-amino group. The specific labeling of the active site by FSBA has helped to define the active site in the recently determined structure of AIR synthetase [Li, C., Kappock, T. J., Stubbe, J., Weaver, T. M., and Ealick, S. E. (1999) Structure (in press)], and suggests additional flexibility in the ATP binding region.

Contact laser vaporization of the prostate in patients on chronic anticoagulant therapy.

The patient with marked bladder outlet obstructive symptoms who is taking anticoagulant medication presents a challenge to the urologist. This report consists of six such patients requiring full anticoagulation with oral warfarin. All patients were treated with the Surgical Laser Technologies neodymium: YAG contact laser using the sapphire tip, while they were fully anticoagulated. All patients had their catheters removed the morning following surgery, and were discharged that same morning. On follow-up all are voiding with excellent streams and have marked reduction in their bladder outlet obstructive symptoms. Contact laser vaporization of the prostate provides an efficient and cost-effective therapeutic option in the management of these high-risk patients.

Reduction of length of stay and cost of transurethral resection of the prostate by early catheter removal.

OBJECTIVE: To determine whether early removal of the indwelling Foley catheter after transurethral resection of the prostate (TURP) significantly shortens the hospital stay without causing additional morbidity and thus saves costs. PATIENTS AND METHODS: For the year commencing 1 July 1991, 119 patients who had undergone TURP had their indwelling catheter removed on the first day after surgery. The results and morbidity of this group of patients were compared with those in 152 patients undergoing TURP during the previous year. The economic consequences of this protocol were calculated using both Medicare and CHAMPUS data. RESULTS: The demographics of the patients in both groups were similar. Post-operative complications occurred in 5% of the study patients and in 6.6% of controls; a transfusion was required in 2.5% and 1.3%, clot retention developed in 1.7% and 3.3% and the hospital stay was reduced from 3.1 to 1.28 days in the study and control patients, respectively. Using Medicare data, the mean cost saving of early catheter removal would be $829 and $1406 for patients aged < 70 and > 70 years, respectively. For CHAMPUS patients, the cost saving would be $1983. CONCLUSION: Early removal of the catheter after TURP did not increase morbidity and maintained the efficacy of the procedure. If this practice was adopted nationally, the savings resulting from the reduction in hospital stay would be considerable.

Contact laser vaporization of the prostate: one surgeon's experience with 50 consecutive cases.

The purpose of this study was to evaluate the efficacy of contact laser vaporization of the prostate as an alternative method of performing transurethral prostatectomy. Fifty patients with bladder outlet obstruction underwent contact laser vaporization of the prostate. Preoperative AUA symptom scores were compared with 3-month postoperative AUA symptom scores. Bleeding, catheter time, average length of hospital stay, and hospital cost are compared to the "gold standard" electrocautery TURP. Prostatic vaporization was performed using a contact laser MTRL-6 round probe, 5 mm in diameter, with the SLT neodymium:YAG (Nd:Yag) contact laser set at 50 W. Procedure time was comparable to that for electrocautery TURP. Average AUA symptom scores were reduced from 22.9 (range, 14-30) preoperatively to 2.1 (range, 0-8) postoperatively. All patients had the foley catheter removed within 24 h; no recatheterizations were required. Of all the patients, 96% were discharged within 24 h; two patients (4%) were not discharged within 24 h because of unrelated coexistent medical problems. All patients were allowed to return to full unrestricted activity within 24 h of discharge. Bleeding was minimal in all cases, with no transfusions required, including three patients in the series on anticoagulant therapy. Hospital costs for the procedure compare favorably to electrocautery TURP. Contact laser TURP using the SLT contact Nd:Yag laser relieved the symptoms of an obstructing prostate comparable to electrocautery TURP. However, these results were achieved with a much shorter hospitalization, a quicker return to full activity, and at a comparable cost.

Balloon dilation of the prostate: correlation with magnetic resonance imaging and transrectal ultrasound findings.

Alternative treatments for benign prostatic hyperplasia are under intense scrutiny. Initial reports on balloon dilation therapy showed success rates of 60% to 90%, although follow-up was brief. We present a prospective non-blinded study assessing the efficacy of an investigational balloon dilatation catheter (105 Fr at 3 atm) as well as the MRI findings preoperatively and postoperatively. Twenty-seven men underwent balloon dilation and have been followed for at least 1 year. Twelve patients (44%) ultimately required definitive transurethral prostatectomy during follow-up. A mild improvement was noted in the symptom score and flow rate in the responder group. Fracture of the anterior commissure was accomplished in only 5 patients (18%) despite diligent efforts. The MRI scans showed no change in the prostate in any patients. Intraoperative transrectal ultrasound scanning suggested that proximal balloon migration can occur. Our experience with this balloon system leads us to recommend that it remain an investigational procedure.

Relative performance characteristics of prostate specific antigen and prostatic specific antigen density for the diagnosis of carcinoma of the prostate.

Prostate specific antigen (PSA) has become an important method for early detection of prostate cancer. It has been suggested that prostate specific antigen density (PSAD) may be a more efficient test for early detection than PSA alone. A series of 327 men undergoing prostate biopsy were evaluated by PSA and PSAD. When the receiver operating characteristic curves of both tests were compared, they demonstrated little improvement in the efficiency of detection with the use of PSAD. The five-fold increase in the cost of PSAD over PSA alone does not justify its inclusion in a plan for early detection for carcinoma of the prostate.

Reactions catalyzed by 5-aminoimidazole ribonucleotide carboxylases from Escherichia coli and Gallus gallus: a case for divergent catalytic mechanisms.

A comparative investigation of the substrate requirements for the enzyme 5-aminoimidazole ribonucleotide (AIR) carboxylase from E. coli and G. gallus has been conducted using in vivo and in vitro studies. In Escherichia coli, two enzymes PurK and PurE are required for the transformation of AIR to 4-carboxy-5-aminoimidazole ribonucleotide (CAIR). The Gallus gallus PurCE is a bifunctional enzyme containing AIR carboxylase and 4-[(N-succinylamino)carbonyl]-5-aminoimidazole ribonucleotide (SAICAR) synthetase. The E. coli PurE and the C-terminal domain of the G. gallus PurCE protein maintain a significant degree of amino acid sequence identity and also share CAIR as a product of their enzymatic activities. The substrate requirements of AIR carboxylases from E. coli and G. gallus have been compared by a series of in vitro experiments. The carbamic acid, N5-carboxyaminoimidazole ribonucleotide (N5-CAIR) is a substrate for the E. coli PurE (Mueller et al., 1994) but not for the G. gallus AIR carboxylase. In contrast, AIR and CO2 are substrates for the G. gallus AIR carboxylase. The recognition properties of the two proteins were also compared using inhibition studies with 4-nitro-5- aminoimidazole ribonucleotide (NAIR). NAIR is a tight-binding inhibitor of the G. gallus AIR carboxylase (K(i) = 0.34 nM) but only a steady-state inhibitor (K(i) = 0.5 microM) of the E. coli PurE. These data suggest significant differences in the transition states for the reactions catalyzed by these two evolutionarily related enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

N5-carboxyaminoimidazole ribonucleotide: evidence for a new intermediate and two new enzymatic activities in the de novo purine biosynthetic pathway of Escherichia coli.

Conversion of aminoimidazole ribonucleotide (AIR) to 4-carboxyaminoimidazole ribonucleotide (CAIR) in Escherichia coli requires two proteins, PurE and PurK, previously thought to be subunits of a single enzyme, AIR carboxylase. Past studies revealing an ATP requirement for this reaction (Meyer et al., 1992), in conjunction with present studies, reveal that PurE and PurK possess independent catalytic activities. PurK is shown, by NMR spectroscopy, to catalyze the conversion of AIR in the presence of HCO3- and ATP to ADP, P(i), and the carbamate of AIR (designated N5-CAIR). PurE has been shown by NMR spectroscopy and kinetic analysis, to catalyze the reversible conversion of N5-CAIR and CAIR. N5-CAIR has a half-life of 0.9 min at pH 7.8 and 30 degrees C. Thus, two new enzymatic activities and a new intermediate have been discovered in the de novo purine biosynthetic pathway of E. coli.

Morbidity with contemporary prostate biopsy.

To determine the incidence of complications associated with contemporary prostate biopsy, a review of 670 men undergoing transrectal prostate biopsy using 18 gauge biopsy needles was conducted. Of the men 580 received 1 to 3 days of ciprofloxacin antibiotic prophylaxis. A total of 16 patients (2.1%) suffered complications of whom 4 (0.6%) required hospitalization. These data demonstrate the low morbidity associated with contemporary transrectal prostate biopsy.

Management of ultrasonically detected nonpalpable testis masses.

As testicular ultrasound has evolved, nonpalpable masses have been detected for which an evaluation and treatment protocol has not been established. Our experience with nonpalpable testis masses detected only by ultrasound in 5 patients is presented, with all patients found to have nonmalignant lesions. We recommend that such cases with negative serum tumor markers and normal chest radiographs be followed with serial ultrasounds. Benign masses will resolve completely, while stable or enlarging masses can be locally excised and inguinal orchiectomy completed only if cancer is found by frozen section. A modified staging system to follow these patients is proposed to determine these patients' prognoses: Stage Ia for inguinally removed nonpalpable cancers, Stage Ib for excised nonpalpable cancers without orchiectomy (false-negative frozen section), and Stage Ic for inguinally removed palpable cancers.

Nuclear medicine and pediatric nephrology.

Radionuclide cystography and renal scintigraphy are the diagnostic procedures of choice in conjunction with ultrasonography in the workup of pediatric urologic or nephrologic patients. Two interesting case reports--a six-month old and a three-month old--are presented.

Cancer of the prostate. Do yearly digital rectal examinations save lives?

Because there is no cure for metastatic adenocarcinoma of the prostate, diagnosis before the tumor spreads is imperative. In this article, Dr Mueller discusses the prognosis of the various tumor stages and strongly advises yearly digital rectal examinations to ensure early detection.

An evaluation of serial digital rectal examinations in screening for prostate cancer.

The purpose of this review is to test the hypothesis that serial digital rectal examinations of the prostate lead to detection of prostate cancer at an earlier and more curable stage. The clinic records of 4,843 patients between 40 and 79 years old seen at the Brooke Army Medical Center prostate cancer screening clinic between January 1979 and September 1985 were reviewed. Of the patients with palpable nodules 122 were found on biopsy to have adenocarcinoma of the prostate. We compared the clinical and, when possible, pathological stage of disease diagnosed at the initial clinical visit to those from patients who had prior normal digital rectal examinations at the screening clinic and who were followed at our clinic. There was a numerically striking difference in the percentage of patients in each group with clinical as well as pathological stage B cancer. Due to the small number of patients in each group these differences were not statistically significant.

Bladder carcinoma presenting as exercise-induced hematuria.

Exercise-induced hematuria is becoming a common diagnosis for postexercise hematuria. However, a number of genitourinary tract diseases also may cause gross or microscopic hematuria in some physically active patients. Four cases of postexercise hematuria in patients with transitional cell carcinoma of the bladder are presented. The authors recommend urologic evaluation with excretory urography and cystoscopy for all patients with postexercise hematuria.

Intravesical alum irrigation for intractable bleeding secondary to adenocarcinoma of the prostate.

We report on 2 patients in whom intractable hematuria was caused by carcinoma of the prostate. Since the hematuria failed to respond to conservative measures, intravesical 1 per cent alum irrigation was used. Hematuria resolved in both patients and no toxicity was observed. Intravesical alum irrigation should be considered in any patient with significant hematuria secondary to carcinoma of the prostate in whom conservative therapy has failed.

Chinese restaurant syndrome: a review.

CRS is a benign, self-limited process that has an excellent prognosis for immediate and rapid recovery. While questions remain about exactly who is susceptible, how much MSG is needed, and even whether MSG is the sole etiologic agent, there appears to be little reason to embark on an extensive workup and treatment regimen with a presumptive diagnosis of MSG intoxication. Rather, knowledge of CRS and recognition of its associated signs and symptoms and its clinical course are important.

Metal fume fever--a review.

Metal fume fever (MFF) is an acute industrial disease caused by the inhalation of a variety of heavy metal oxides. MFF occurs most commonly during welding operations, particularly those involving zinc oxide. The illness is of short duration and produces symptoms of cough, fever, chills, malaise, and myalgias. Its etiology is uncertain, and its diagnosis is difficult because symptoms resemble a number of pulmonary illnesses. Supportive treatment, with bed rest, analgesics, and fever control is used for symptomatic relief. Emergency medicine physicians must differentiate the clinical picture from other common respiratory illnesses. The mainstay of therapy for MFF consists of recognizing the disease and preventing subsequent exposure to harmful metals.