The Pyloritek test and the CLO test: accuracy and incremental cost analysis

OBJECTIVE

The aim of this study was to compare the Pyloritek test (a 1-h rapid urease test) to the widely used CLO test.

METHODS

Seventy-one patients undergoing upper endoscopy were studied. All patients gave informed consent. A single antral biopsy specimen was obtained for the CLO test, and another was obtained for the Pyloritek test. Additional specimens were obtained for culture and processed in the event of a discordant result. The Pyloritek assay was read at 1 h by one observer. The CLO test was read at 24 h by an observer blinded to the results of the Pyloritek assay.

RESULTS

There were 18 males and 53 females, and the mean age (+/- SEM) was 53 +/- 17 yr. Thirty-two patients had a positive result on the CLO test, and 39 had a negative test result. Of the 32 patients with a positive CLO test result at 24 h, 31 were positive by the Pyloritek test at 1 h. All 39 patients with negative CLO test results had negative Pyloritek test results as well. There was one discordant result, a negative Pyloritek test result and a positive CLO test result. Culture demonstrated growth of Helicobacter pylori. The kappa value, a measure of the reliability of the Pyloritek test compared with the CLO test, was 0.972 (SE, 0.0284; 95% confidence interval, 0.925-1). Marginal cost-effectiveness analysis favored the Pyloritek test.

CONCLUSIONS

Results of the Pyloritek test at 1 h and the CLO test at 24 h are comparable in terms of detection of urease activity.

Hospital costs and severity of illness in three types of elective surgery

BACKGROUND

If patients who are more severely ill have greater hospital costs for surgery, then health-care reimbursements need to be adjusted appropriately so that providers caring for more seriously ill patients are not penalized for incurring higher costs. The authors' goal for this study was to determine if severity of illness, as measured by either the American Society of Anesthesiologists Physical Status (ASA PS) or the comorbidity index developed by Charlson, can predict anesthesia costs, operating room costs, total hospital costs, or length of stay for elective surgery.

METHODS

The authors randomly selected 224 inpatients (60% sampling fraction) having either colectomy (n = 30), total knee replacement (n = 100), or laparoscopic cholecystectomy (n = 94) from September 1993 to September 1994. For each surgical procedure, backward-elimination multiple regression was used to build models to predict (1) total hospital costs, (2) operating room costs, (3) anesthesia costs, and (4) length of stay. Explanatory candidate variables included patient age (years), sex, ASA PS, Charlson comorbidity index (which weighs the number and seriousness of coexisting diseases), and type of insurance (Medicare/Medicaid, managed care, or indemnity). These analyses were repeated for the pooled data of all 224 patients. Costs (not patient charges) were obtained from the hospital cost accounting software.

RESULTS

Mean total hospital costs were $3,778 (95% confidence interval +/- 299) for laparoscopic cholecystectomy, $13,614 (95% CI +/- 3,019) for colectomy, and $18,788 (95% CI +/- 573) for knee replacement. The correlation (r) between ASA PS and Charlson comorbidity scores equaled 0.34 (P < .001). No consistent relation was found between hospital costs and either of the two severity-of-illness indices. The Charlson comorbidity index (but not the ASA PS) predicted hospital costs only for knee replacement (P = .003). The ASA PS, but not the Charlson index, predicted operating room and anesthesia costs only for colectomy (P < .03).

CONCLUSIONS

Severity of illness, as categorized by ASA PS categories 1-3 or by the Charlson comorbidity index, was not a consistent predictor of hospital costs and lengths of stay for three types of elective surgery. Hospital resources for these lower-risk elective procedures may be expended primarily to manage the consequences of the surgical disease, rather than to manage the patient's coexisting diseases.

Identification of a potential role for the adventitia in vascular lesion formation after balloon overstretch injury of porcine coronary arteries

BACKGROUND

In the present series of experiments, we examined the onset of cell proliferation and growth factor expression after balloon overstretch injury to porcine coronary arteries.

METHODS AND RESULTS

Domestic juvenile swine underwent balloon overstretch injury to the left anterior descending and circumflex coronary arteries with standard percutaneous transluminal coronary angioplasty balloon catheters. To identify proliferating cells, 5-bromo-2-deoxyuridine (BrDU) was administered over a period of 24 hours before the animals were killed at either 1, 3, 7, or 14 days after injury. Immunohistochemistry was performed with monoclonal antibodies to BrDU and smooth muscle cell markers. Three days after injury, a large number of proliferating cells were located in the adventitia, with significantly fewer positive cells found in the media and lumen. Seven days after injury, proliferating cells were found primarily in the neointima, extending along the luminal surface. In situ hybridization for PDGF A-chain and beta-receptor mRNAs revealed that the expression of these two genes was closely correlated with the sites of proliferation at each time point. Studies in which BrDU was injected between days 2 and 3 and the animals were killed on day 14 suggested that the proliferating adventitial cells may migrate into the neointima.

CONCLUSIONS

These data suggest that adventitial myofibroblasts contribute to the process of vascular lesion formation by proliferating, synthesizing growth factors, and possibly migrating into the neointima. Increased synthesis of alpha-smooth muscle actin observed in the adventitial cells after arterial injury may constrict the injured vessel and contribute to the process of arterial remodeling and late lumen loss after angioplasty.

Functional analysis of histones H2A and H2B in transcriptional repression in Saccharomyces cerevisiae

The presence of H2A-H2B dimers in nucleosomes can inhibit the binding of transcription factors to chromatin templates. To study the roles of histones H2A and H2B in transcriptional repression in vivo, mutant forms of these histones were analyzed in two different assay systems. Two repression domains were identified in H2A. One domain includes residues that fall in the beginning of the H2A-H2B dimerization region, and the second is in the H2A N terminus, a region of potential interactions with nonhistone proteins. The function of H2A and H2B in one repression assay was found to be dependent on three SPT (suppressor of Ty) genes whose products are important for chromatin-mediated repression. These results suggest that repressive chromatin structure may be established through the interactions of the Spt proteins with these histones. In contrast, other proteins, the products of the HIR (histone regulation) genes, may function to direct H2A and H2B to specific promoters.

Advantage of Inoue balloon catheter in mitral balloon valvotomy: experience with 220 consecutive patients

Percutaneous mitral balloon valvotomy (PMV) using the Inoue balloon catheter was attempted in 220 consecutive patients with severe symptomatic mitral stenosis. Their age range was 10-63 mean 30 +/- 10 years; 161 patients were females and 59 were males; 29 patients were in atrial fibrillation. Eleven patients were pregnant; 14 patients underwent previous surgical commissurotomy. The procedure was technically successfully performed in 215 (97.7%) patients. The mean fluoroscopy time was 15.5 +/- 6.4 min and mean procedure time was 109 +/- 79 min. Optimal results (group I) was achieved in 207 patients who have mitral score of 7 +/- 1. PMV resulted in decrease in left atrial pressure from 23 +/- 5 to 14 +/- 4 mm Hg (P < 0.001), the mean mitral valve gradient (MVG) decreased from 15 +/- 4 to 6 +/- 3 mm Hg (P < 0.001). The mitral valve area (MVA) by catheter increased from 0.7 +/- 0.2 to 1.7 +/- 0.5 cm2 (P < 0.001) and MVA as determined by echocardiography (2DE) increased from 0.8 +/- 0.1 to 1.9 +/- 0.3 cm2 (P < 0.001). The results were suboptimal in eight patients who have a mitral score of 10 +/- 1 (group II) MVA by catheter increased from 0.7 +/- 0.2 to 1 +/- 0.1 cm2 and Doppler MVA increased from 0.8 +/- 0.1 to 1.3 +/- 0.1 cm2. There were no deaths or thromboembolism. Two patients developed cardiac tamponade; mild mitral regurgitation (MR) developed in 24 patients (11%) and increased by one grade in another 22 patients (10%). Severe MR was encountered in three patients (1.4%). A small ASD (QP/QS < or = 1.3) was detected by oximetry in 5% of patients and by color-flow mapping in 26% of patients. One hundred fifty-eight patients from group I were followed up, for a mean of 32 +/- 12 months; MVA remained at 1.7 +/- 0.4 cm2. Seven patients developed mitral restenosis in group I, and 5 out of 8 patients developed restenosis in group II. We conclude that the hemodynamic results are good and comparable with those reported with double balloon technique. However, the Inoue balloon has several advantages over the double balloon technique: (1) low incidence of mitral regurgitation and ASDs; (2) shorter procedure and fluoroscopy time; and (3) low complication rates and the valve anatomy affects the immediate and late outcome of mitral balloon valvotomy.

Where are the costs in perioperative care? Analysis of hospital costs and charges for inpatient surgical care

BACKGROUND

Many health-care institutions are emphasizing cost reduction programs as a primary tool for managing profitability. The goal of this study was to elucidate the proportion of anesthesia costs relative to perioperative costs as determined by charges and actual costs.

METHODS

Costs and charges for 715 inpatients undergoing either discectomy (n = 234), prostatectomy (n = 152), appendectomy (n = 122) or laparoscopic cholecystectomy (n = 207) were retrospectively analyzed at Stanford University Medical Center from September 1993 to September 1994. Total hospital costs were separated into 11 hospital departments. Cost-to-charge ratios were calculated for each surgical procedure and hospital department. Hospitalization costs were also divided into variable and fixed costs (costs that do and do not change with patient volume). Costs were further partitioned into direct and indirect costs (costs that can and cannot be linked directly to a patient).

RESULTS

Forty-nine (49%) percent of total hospital costs were variable costs. Fifty-seven (57%) percent were direct costs. The largest hospital cost category was the operating room (33%) followed by the patient ward (31%). Intraoperative anesthesia costs were 5.6% of the total hospital cost. The overall cost-to-charge ratio (0.42) was constant between operations. Cost-to-charge ratios varied threefold among hospital departments. Patient charges overestimated resource consumption in some hospital departments (anesthesia) and underestimated resource consumption in others (ward).

CONCLUSIONS

Anesthesia comprises 5.6% of perioperative costs. The influence of anesthesia practice patterns on "downstream" events that influence costs of hospitalization requires further study.

Differential-effects of max proteins (long and short) on growth and differentiation of murine erythroleukemia-cells

The myc gene product belongs to a family of basic, Helix-Loop-Helix, Leucine Zipper (b-HLH-LZ) proteins involved in cell growth, differentiation and tumorigenesis. The Max protein dimerizes with Myc to form a complex which binds to DNA and promotes transcription of target genes. Max exists in two major forms, Max-9 (long) and Max (short), which differ by 9 amino acids just amino to the basic region. We compared the in vivo behavior of the two forms in stable transfectants of long and short wild type (Lwt, Swt) and basic region mutants (Lbm, Sbm). While both Lwt-max and Swt-max clones exhibit delays in cell growth and differentiation, these delays are far more pronounced in the Lwt-max clones. In contrast, no difference is noted between Lbm-Max and Sbm-Max in their observed ability to delay growth, to accelerate HMBA-induced differentiation and to induce spontaneous differentiation. We suggest that a difference in affinity for DNA underlies the differential activities of Lwt- and Swt-Max.

Magnetic resonance imaging compared with angiography in the evaluation of intermediate-term result of coarctation balloon angioplasty

Between July 1986 and December 1990, 24 consecutive adult patients with native coarctation of the aorta underwent balloon dilatation. Their ages ranged from 15 to 55 (mean 25) years. Dissection of the aorta developed in one patient. The remaining 23 patients were restudied by catheterization and magnetic resonance imaging (MRI) 8 to 60 (mean 21) months after dilatation. Both studies were performed between 1 and 180 (mean 40) days of each other. The diameter of the aorta at the site of previous coarctation was measured on angiogram and MRI by two independent observers. The data were compared by means of linear regression analysis. The gradient across the previous coarctation site ranged from 0 to 20 (mean 7 +/- 7.3) mm Hg. The diameter of the aorta at the site of previous coarctation measured on angiogram was 13.7 +/- 3.7 mm and on MRI it measured 13.5 +/- 3.7 mm, with excellent correlation (r = 0.96, SEE = 0.92, p < 0.001). Two patients had small aneurysms 2 cm in diameter demonstrated by angiography and MRI, and two patients developed restenosis, diagnosed correctly by both cardiac catheterization and MRI. This study demonstrates that MRI provides excellent visualization of the anatomy of the aorta and is a good noninvasive method for follow-up of patients undergoing balloon coarctation angioplasty.

Putative anticarcinogenic actions of carotenoids: nutritional implications

This review provides an update on nutritional aspects of carotenoids (as distinct from retinoids), with specific relevance to anticarcinogenesis. Critical gaps remain in our knowledge of the nutritional functions of carotenoids despite an overwhelming accumulation of research data in areas tangential to human nutrition. In addition to their roles as precursors of retinol and retinoids, carotenoids have distinct functions of their own in animals and humans. In vitro they are antioxidants with a broad range of potencies. In vivo, they protect porphyrics against sunlight. The evidence for anticarcinogenic actions of beta-carotene in certain specified test situations is persuasive. Nevertheless, despite a large number of studies demonstrating protection by carotenoids, the characteristics that render a given carotenoid effective and the relative efficacy of the individual carotenoids are not known. Moreover, dose-response and pharmacokinetic relationships remain virtually unexplored. Research to uncover mechanisms of protection by carotenoids is, for technical reasons, painfully slow. Epidemiological studies reveal associations but not cause and effect. To explore cause and effect, intervention trials are underway, hampered by the paucity of data regarding optimal choice of carotenoid, dosage, and regimen. The in vitro test systems that would provide this information are not available because the molecular sites relevant to the chemopreventive action of carotenoids are obscure. Each of these problems has a solution, but not a simple one. Until these are resolved, blanket recommendations regarding supplementation will remain problematic. To this point, health authorities have not recommended dietary supplementation with carotenoids. Instead, they recommend increased consumption of yellow and dark green carotenoid-rich vegetables. In the future, an individual at risk for a particular carcinogenic process may be recommended a supplement of the most appropriate anticarcinogen, specific to their individual endowment of genetic and environmental risk factors. This review emphasizes not only what is known but also what is not known. Consequently we identify priorities for research that, if undertaken, will allow such recommendations to be made or discounted with more confidence.

Use of therapeutic humour by psychiatric nurses

Humour is an essential part of our everyday communication. While for the nurse, there are differences between social and clinical environments, humour cannot be turned on or off in either. Consciously attempting to avoid humour leads to stunted, rigid interaction.

Specificity domains distinguish the Ras-related GTPases Ypt1 and Sec4

The essential Ras-related GTPases Ypt1 and Sec4 act at distinct stages of the secretion pathway in the yeast Saccharomyces cerevisiae: Ypt1 is required for vesicular transport from the endoplasmic reticulum to the Golgi apparatus, whereas Sec4 is required for fusion of secretory vesicles to the plasma membrane. Here we use chimaeras of the two proteins to identify a 9-residue segment of Ypt1 that, when substituted for the analogous segment of Sec4, allows the chimaera to perform the minimal functions of both proteins in vivo. This segment corresponds to loop L7 of the p21ras crystal structure. Substitution of a 24-residue Ypt1 segment, including the residues just mentioned, together with 12 residues of Ypt1 corresponding to the 'effector region' of p21ras (loop L2; refs 7,8), transforms Sec4 into a fully functional Ypt1 protein without residual Sec4 function.

Growing up with a psychotic mother: a retrospective study

Nine adults who had been reared by mothers diagnosed with psychosis reported on their childhood experiences. Analysis of the retrospective data revealed the five common themes of abuse and neglect, isolation, guilt and loyalty, grievances about mental health services, and social supports. The resilience and coping strategies of the participants are examined, and implications for therapeutic interventions with such families are discussed.

Balloon valvotomy for pregnant patients with severe pliable mitral stenosis using the Inoue technique with total abdominal and pelvic shielding

Balloon valvotomy by means of the Inoue technique was attempted in seven pregnant (5 to 9 months) patients with severe mitral stenosis; the mean age of the patients was 32 +/- 8 years, and all had a two-dimensional echocardiographic mitral valve score of < 8. Indications for Inoue balloon valvotomy included severe symptomatic mitral stenosis with a Doppler mitral valve area < or = 1 cm2 and heart failure refractory to medical therapy, or absolute contraindications for the use of beta-blockade; Inoue valvotomy was also indicated for patients who lived a long distance from the hospital. Inoue balloon valvotomy was performed with no angiography and total pelvic and abdominal shielding; the balloon catheter was introduced into the right atrium without the aid of fluoroscopy, which was used for the transseptal puncture. Stepwise two-dimensional echocardiographic Doppler mitral valve dilatation was done. After Inoue balloon valvotomy the mean Doppler mitral valve area increased from 0.8 +/- 0.1 to 2.0 +/- 0.3 cm2 (p < 0.01) and by two-dimensional echocardiography from 0.8 +/- 0.2 to 1.9 +/- 0.3 cm2 (p < 0.01), with no significant Doppler residual stenosis (defined as mitral valve area < or = 1.5 cm2). The mean total fluoroscopy time was 16 +/- 7 minutes. The degree of mitral regurgitation increased in two patients from grade 1+/4+ to grade 2+/4+ and from grade 0+/4+ to grade 2+/4+, respectively. There was no mortality or significant morbidity. Pregnancy was uneventful in all patients, and all were delivered of normal babies without complications.(ABSTRACT TRUNCATED AT 250 WORDS)

PET imaging of opiate receptor binding in human epilepsy using [18F]cyclofoxy

We used [18F]cyclofoxy (CF), a potent opiate antagonist with affinity for mu and kappa receptors, and the Scanditronix PC1024-7B PET scanner to study 14 patients with complex partial seizures (CPS), and 14 normal controls. Epileptic foci were localized by prolonged EEG-video monitoring. EEG was recorded continuously during each scan. Immediately before CF administration, [15O]labeled water was used to measure cerebral blood flow, and showed hypoperfusion ipsilateral to the EEG focus. Blood samples (corrected for radiolabeled metabolites) and tissue time-activity data were acquired over 90 min following bolus CF injection. Anatomic regions were outlined directly on the PET images. A kinetic model was used to derive the total volume of distribution (Vt) in each brain region. Specific binding (Vs) was determined by substracting non-specific binding (Vt) measured in a receptor-poor brain region (occipital cortex). Regions with high Vs included mesial temporal lobes, thalamus, basal ganglia, and frontal cortex. Individual patients appeared to have higher binding in temporal lobe ipsilateral to the EEG focus, but there was no asymmetry for the patients as a group in mean Vt or Vs in anterior mesial, posterior mesial, anterior lateral, posterior lateral temporal cortex, thalamus, basal ganglia, or, for Vt, in regions of low specific binding: occipital lobe, parietal lobe, cerebellum.

Protection by beta-carotene and related compounds against oxygen-mediated cytotoxicity and genotoxicity: implications for carcinogenesis and anticarcinogenesis

beta-Carotene protects against photooxidative dermatitis in porphyric humans and mice by quenching of photoactivated species. Other actions of beta-carotene in vivo are explained on the basis of its ability to scavenge free radicals in vitro. For example, in guinea pigs treated with CCl4, beta-carotene decreases pentane and ethane production. Epidemiological studies link low serum beta-carotene levels to elevated risk of lung and other cancers, and in intervention trials, beta-carotene diminishes preneoplastic lesions. However, the dose/response relationships are not well established, and antineoplastic mechanisms await clarification. Given a radical quenching mechanism, beta-carotene should block tumor promotion, but more typically the site of action is progression and an even later role in invasion has not been ruled out. Some antineoplastic actions of carotenoids (such as increased rejection of fibrosarcomas in mice) are attributed to immunoenhancement; others may reflect conversion to retinoids and subsequent gene regulation. Carotenoids other than beta-carotene may act at an earlier stage of carcinogenesis or be more effective as anticarcinogens at certain target sites. As scavengers of hydroxyl radicals, canthaxanthin and astaxanthin are more effective than beta-carotene. Canthaxanthin is sometimes more effective than beta-carotene in chemoprevention, but it is sometimes completely ineffective. Lycopene quenches singlet oxygen more than twice as effectively as beta-carotene. However, the antineoplastic actions of lycopene or astaxanthin remain untested. Explorations of the interactions of carotenoids with other nutrients are just beginning. Dietary fat increases absorption of carotene but decreases antineoplastic effectiveness. Research is hampered by technical problems, including the unavailability of rigorous controls, the instability of carotenoids, and the heterogeneous phase structure induced by hydrophobic compounds in aqueous media. Areas of current controversy and promising approaches for future research are identified.

Balloon coarctation angioplasty in adolescents and adults: early and intermediate results

Twenty-three adolescent and adult patients with native coarctation of the aorta underwent balloon dilatation. Dissection of the aorta developed in one patient. Data were collected on the remaining 22 patients. They ranged in age from 15 to 55 years (mean 23 +/- 9.2 years). Invasive measurement of the peak systolic gradient (PSG) and biplane angiography were performed before and immediately after angioplasty and at follow-up 4 to 48 months (mean 15 months) later. PSG before dilatation was 37 to 100 mm Hg (mean 66.9 +/- 19.9 mm Hg) and decreased to 0 to 30 mm Hg (mean 9.1 +/- 11 mm Hg) immediately after dilatation (p less than 0.001). Restenosis occurred in two patients 6 months after dilatation, and one patient had an incomplete dilatation. These three patients underwent successful redilatation and remained improved 12 to 19 months later. There was no significant change in gradient at repeat catheterization in the remaining 20 patients. PSG was 0 to 20 mm Hg (mean 5.8 +/- 7.2 mm Hg). Angiography showed that a small aneurysm developed in one patient immediately after dilatation and in another 6 months later. Eleven patients were restudied more than once, and no change in gradient or size of the aneurysm was noted at mean follow-up 25 months after dilatation. This study demonstrated that balloon angioplasty is an effective method of treating adolescent and adult patient with native coarctation of the aorta. However, because of the uncertain natural history of aneurysm after dilatation, this procedure should be considered investigational until much longer follow-up times are available.

Intracardiac rhabdomyosarcoma: transesophageal echocardiographic findings and diagnosis

Transesophageal echocardiography (TEE) was performed on a 41-year-old woman who presented with a cerebrovascular accident. TEE confirmed the presence of a morphologically bizarre biatrial tumor with precarious, vigorous motion throughout the cardiac cycle. Surgical intervention was decided on, and the patient underwent cardiac surgery for tumor excision 16 hours after TEE. Intraoperative frozen section diagnosis was spindle cell sarcoma, and subsequent immunohistochemical analysis showed the tumor to be a rhabdomyosarcoma. The data are presented here, and the role of TEE to establish a preoperative diagnosis of intracardiac tumor is discussed.

Encapsulation of proteins in transparent porous silicate glasses prepared by the sol-gel method

Novel sol-gel synthetic techniques were used to immobilize copper-zinc superoxide dismutase (CuZnSOD), cytochrome c, and myoglobin (Mb) by encapsulation in stable, optically transparent, porous silica glass matrices under mild conditions such that the biomolecules retained their characteristic reactivities and spectroscopic properties. The resulting glasses allowed transport of small molecules into and out of the glasses at reasonable rates but nevertheless retained the protein molecules within their pores. Chemical reactions of the immobilized proteins could be monitored by means of changes in their visible absorption spectra. Silica glasses containing the immobilized proteins were observed to have similar reactivities and spectroscopic properties to those found for the proteins in solution. For example, encapsulated CuZnSOD was demetallated and remetallated, encapsulated ferricytochrome c was reduced and then reoxidized, and encapsulated met Mb was reduced to deoxy Mb and then reacted either with dioxygen to make oxy Mb or with carbon monoxide to make carbonyl Mb.

Percutaneous mitral valvotomy with the Inoue balloon catheter in children and adults: immediate results and early follow-up

Percutaneous mitral balloon valvotomy (PMV) using the Inoue balloon catheter was attempted in 60 consecutive patients with severe symptomatic mitral stenosis. There were 10 children (mean age 13 years) and 50 adults (mean age 31 years). Forty patients were females and 20 were males; 53 were in sinus rhythm. The procedure was technically successfully performed in 57 (95%) patients. There were no deaths or thromboembolic complications. Balloon valvotomy was done using a 22 to 30 mm diameter catheter with the echo/Doppler guided stepwise mitral dilatation technique. After PMV the mean left atrial pressure decreased from 23.0 +/- 5.0 to 14.0 +/- 4.0 mm Hg (p less than 0.001). The mean mitral valve gradient (MVG) decreased from 15.0 +/- 4.0 to 6.0 +/- 2.0 mm Hg (p less than 0.001). The mitral valve area (Gorlin formula) increased from 0.7 +/- 0.2 to 1.6 +/- 0.4 cm2 (p less than 0.001). The mitral valve area as determined by echocardiography increased from 0.8 +/- 0.1 to 1.9 +/- 0.3 cm2 (p less than 0.001). Mild mitral regurgitation (MR) developed in six patients (11%) and increased by one grade in another five patients (9%). No patient developed severe mitral regurgitation. Mitral valve area at mean follow-up of 4.8 months remained unchanged at 1.9 +/- 0.3 cm2. We conclude that PMV, using the Inoue balloon catheter, is safe and effective in the treatment of severe mitral stenosis in children and adults, without inducing significant mitral regurgitation.

Measurement of stimulated emission cross section and fluorescence branching ratio for Nd(3+) in sodium-beta'' alumina

Room-temperature measurements of laser emission cross sections of Nd(3+) ion in sodium-beta" alumina at 1.06 and 1.35 microm as well as the fluorescence branching ratios of (4)F(3/2) to (4)I(j) manifolds are reported. A theoretical calculation based on absolute absorption measurements when a modified Judd-Ofelt phenomenological intensity analysis was used is reported. The cross sections thus determined are sigma(1.06) = 3.1 +/- 0.3 x 10(-20) cm(2) and sigma(1.35) = 0.6 +/- 0.1 x 10(-20) cm(2), respectively. The emission cross section at 1.06 microm was also determined by small-signal-gain measurements and was found to be in good agreement with the above value.

Regional brain measurement of Bmax and KD with the opiate antagonist cyclofoxy: equilibrium studies in the conscious rat

Brain distribution of the opiate receptor antagonist, cyclofoxy (CF), was evaluated at equilibrium in rats. A combination of i.v. injection and constant i.v. infusion was used to administer CF over a wide dose range (2.4-450 nmol/rat). Kinetic simulations and experimental results showed that this administration schedule accomplishes "true" tissue-blood equilibrium of CF within 60 min. To estimate the receptor-ligand binding parameters, we assumed that the CF concentration at the receptor site is identical to that in plasma water at equilibrium, and can be calculated from measured blood data after corrections for radiolabeled metabolites and plasma protein binding. This assumption was supported by CSF and plasma water measurements at equilibrium. Regional KD, Bmax, and a nonspecific tissue binding equilibrium constant (Keq) were estimated by fitting the tissue and plasma water concentrations to a single receptor model; the estimated values were 1.4-2.9 nM, 15-74 pmol/g of tissue, and 5.2-8.0, respectively. They are in good agreement with previous in vitro measurements (Rothman and McLean, 1988) as well as in vivo estimates from i.v. injection experiments (Sawada et al., 1990c). The conventional method to estimate the receptor-ligand binding parameters using data from cerebellum to approximate nonspecific tissue binding was found to be unacceptable. Although cerebellum is a brain region with no opiate receptors in rats, small differences in nonspecific tissue binding in different brain regions resulted in significant overestimations of KD and Bmax with this method. Receptor-active and -inactive enantiomers [[18F](-)-CF and [3H](+)-CF)] were simultaneously administered to the same animal and the receptor-bound CF concentration could be accurately measured; this method was used to estimate Bmax from a single study in a single animal and has potential for direct application in human studies using positron emission tomography.

Mitral balloon valvotomy using the Inoue balloon technique for selected patients with severe pliable rheumatic mitral valve stenosis: immediate and short-term results

We selected 40 patients with severe symptomatic rheumatic mitral stenosis for balloon valvotomy using the Inoue balloon technique. The patients' mean age was 31 +/- 14 years and there were 24 females and 16 males. The patients were selected according to the following echo/Doppler criteria; 1. Severe mitral stenosis, i. e. mitral valve area (MVA) less than 1.1 cm2; 2. pliable anterior mitral valve leaflet; 3. absence of calcification of the mitral commissures and 4. absence of significant subvalvular mitral valve disease (Block echo score less than 8). We failed to cross the mitral valve in three cases and repeat attempts in two patients with higher transeptal puncture was successful. Thirty-nine procedures were technically successful (98%). There were no complications. We used an Inoue balloon size 24-30 mm using echo/Doppler guided stepwise mitral dilatation. After mitral balloon valvotomy, the MVA increased from 0.8 +/- 0.2 to 1.7 +/- 0.5 cm2 (p less than 0.001). Five patients developed mild mitral regurgitation and in one patient the degree of mitral regurgitation increased from mild to moderate. The mean mitral valve area 48 hours after the procedure measured 1.9 +/- 0.4 cm2 (echo/Doppler); one patient (2.5%) had residual mitral stenosis (MVA less than 1.5 cm2). At six weeks follow-up study the mean mitral valve area was 1.9 +/- 0.5 cm2 (Echo/Doppler), with no restenosis. We conclude that in selected cases of severe pliable mitral stenosis, the Inoue balloon technique achieves a greater than 100% increase of the MVA, without inducing significant iatrogenic mitral regurgitation or residual stenosis.

Coronary artery disease and apolipoprotein A-I/C-III gene polymorphism: a study of Saudi Arabians

The infrequent band of 3.2-kb of the apolipoprotein A-I/C-III polymorphic region has previously been found to be associated with coronary artery disease and with hypertriglyceridaemia in Caucasians. We studied the apolipoprotein A-I/C-III gene cluster polymorphism in 97 Saudi Arabians in relation to coronary artery disease. Patients were categorized as being with or without coronary artery disease on the basis of coronary angiography. Genomic blotting of Sac I-digested chromosomal DNA with the use of an apolipoprotein A-I gene probe revealed 4.2-kb and 3.2-kb hybridization bands. The genotype frequency of patients with and without coronary artery disease was not different. The frequency of the 3.2-kb allele occurred in 16% of patients with coronary artery disease and in 21% of patients with normal coronary arteries (non-significant). In conclusion, we have not been able to confirm in Saudi Arabians associations previously reported in Caucasians of the 3.2-kb band and coronary artery disease.

Percutaneous balloon pulmonary valvuloplasty in sickle cell anemia: a case report

Percutaneous balloon pulmonary valvuloplasty was performed on a 19-year-old female who had moderate pulmonary valve stenosis with sickle cell anemia. The patient developed sickle cell crisis resulting in occipital infarction, but she made a good recovery. We describe this case and the methods of reducing the risk of sickle cell crisis.

Kinetic analysis of the opiate antagonist cyclofoxy in rat brain: simultaneous infusion of active and inactive enantiomers

The opiate antagonist (-)-cyclofoxy [(-)-CF] and the receptor inert enantiomer (+)-CF were radiolabeled with 18F or 3H and administered to conscious Sprague-Dawley rats; an isotope effect was not observed. Constant i.v. infusion of both 18F-(-)-CF and 3H-(+)-CF in tracer amounts showed a marked difference in the tissue level of 18F-(-)-CF among various brain structures, whereas the values for 3H-(+)-CF were lower and much less variable. Co-infusion of unlabeled (-)-CF (1 mg/rat) did not change the tissue binding of 3H-(+)-CF in any brain structure, but reduced that of 18F-(-)-CF to the same level as 3H-(+)-CF. These results demonstrate an identical nonspecific tissue binding for (+)- and (-)-CF in vivo, and suggest that (+)-CF can be used to measure the "nonspecific" component of (-)-CF binding in brain. A nonlinear analysis of the 3H-(+)-CF data indicated the presence of both "instantaneous" and time-dependent components in nonspecific tissue binding and that nonspecific binding varied 1.5-fold in different brain structures. The combined 3H-(+)-CF and 18F-(-)-CF data were fitted to a four-compartment model, which includes parameters for capillary transport, "instantaneous" and time-dependent nonspecific tissue binding, as well as receptor association and dissociation. The receptor-association rate constant varied considerably in various structures of cerebrum (2.0-8.7 min-1), whereas receptor dissociation was estimated within a narrow range (0.12-0.17 min-1). The receptor binding potential (receptor association/dissociation) ranged between 12.7 and 56.2 and was in good agreement with previous estimates in vitro.

Regression of infundibular pulmonary stenosis after successful balloon pulmonary valvuloplasty in adults

Between July 1985 and March 1988, 22 adult patients with congenital pulmonary stenosis underwent balloon pulmonary valvuloplasty. There were 10 males and 12 females aged 16-45 (average 25 +/- 9.9) years. All patients had additional mild to severe infundibular stenosis; 16 were restudied 6-36 (mean 12.6) months later by repeat catheterization. Student's t-test was used for comparison of data. Right ventricular (RV) systolic pressure before dilatation was 84-196 (mean 129 +/- 32.3) mm Hg, and the peak pulmonary gradient (PPG) was 60-176 (mean 111 +/- 33.2) mm Hg immediately after dilatation. The RV systolic pressure dropped to 32-140 (mean 59.2 +/- 27) (P less than 0.001); and PPG dropped to 10-113 (mean 37.8 +/- 26.4) (P less than 0.001), and the infundibular gradient ranged from 8 to 113 (mean 35.1 +/- 25.8) mm Hg. The infundibular diameter, before dilatation, ranged from 2 to 15 (mean 9.5 +/- 4) mm Hg. At repeat catheterization, the RV systolic pressure dropped further to 33-66 (mean 42.8 +/- 9.7) mm Hg and the PPG was reduced to 0-48 (mean 18.4 +/- 10.9) mm Hg (P less than 0.001). The infundibular gradient regressed to 0-34 (mean 15 +/- 8.8) mm Hg (P less than 0.001). The infundibular diameter increased to 8-25 (mean 15.8 +/- 5.4) (P less than 0.001). It is concluded that moderate to severe infundibular stenosis, in adults, can regress after successful pulmonary valvuloplasty.

[Short- and long-term problems in dilatation of untreated aortic isthmus stenosis in children]

We examined problems and complications during and after balloon dilation of native coarctation of the aorta in 31 children with a mean age at first dilation of 5.77 +/- 5.4 years (0.08-16 years), who had a total of 37 balloon dilations. Twenty-six patients were restudied 3 to 24 months after the first procedure. In six patients, because of recoarctation, further dilations were performed. In two patients the second procedure was not successful and they required surgery. In 14/37 (37.8%) dilations the routine sedation was insufficient. The retrograde catheter could be introduced percutaneously in all but one patient. Because of small femoral arteries the introduction of the balloon catheter was not possible in three cases (8.1%). In three more patients (8.1%) the adequate catheters were not in stock. Complications included: transfusion because of blood loss in six patients (16.2%), chest pain in three (8.1%), rupture of balloon in three (8.1%), thrombectomy in three (8.1%), and partial reopening of ductus arteriosus in one patient. Duration of hospital stay was a mean of 1.81 days +/- 1.65 (range 1-9 days). Ninety percent of the patients were discharged within 2 days. On follow-up (range: 3-50 months), eight patients (21.6%) had a weak femoral pulse, of whom only one had an absent pulse, eight patients (21.6%) had paradoxical hypertension despite good dilation and no significant gradients, and only one patient showed a small aneurysm. We conclude that balloon angioplasty of native coarctation is a successful and relatively safe method of treatment of native coarctation. The most serious complication is arterial occlusion of the affected leg.(ABSTRACT TRUNCATED AT 250 WORDS)

Laser behavior and photostability characteristics of organic dye doped silicate gel materials

The solgel process is a solution synthesis technique which provides a low temperature chemical route for the preparation of rigid transparent matrix materials. Luminescent organic dye molecules have been incorporated via the solgel method into organically modified silicate (ORMOSIL) polymer host matrices. Optical gain, laser oscillation, and photostability of rhodamine and coumarin dyes doped into ORMOSIL gels are reported. The gel laser materials exhibit peak gain values of 40 cm(-1) and show improved photostability with respect to comparable polymeric host materials.

Lectin-resistant CHO cells: selection of seven new mutants resistant to ricin

In attempts to isolate new CHO glycosylation mutants, selection protocols using plant lectins that bind galactose residues of cell surface carbohydrates were applied to mutagenized CHO populations. The lectins were used alone or in combination to obtain seven ricin-resistant phenotypes. Each mutant had distinctive properties compared with previously described ricin-resistant CHO cells. One of the new phenotypes was dominant in somatic cell hybrids, and the others were recessive. Complementation analyses between related lectin-resistant (LecR) phenotypes indicated that each new isolate represented a novel genotype. Five of the mutants had properties typical of new CHO glycosylation mutants. The remaining two mutants were not readily categorized. Although they did not appear to be ricin-internalization or protein-synthesis mutants, they also did not display the marked alterations in sensitivity to several lectins of different sugar specificity expected for glycosylation mutants. The seven new LecR mutants described in these studies brings the total number of different LecR CHO mutants isolated by this and other laboratories to about 40. Criteria for identifying new LecR mutations in CHO cells are discussed.

Doppler echocardiography in the evaluation of tricuspid stenosis

Seventeen patients (12 with native and five with prosthetic tricuspid valves) with tricuspid stenosis were studied by Doppler echocardiography followed by cardiac catheterization within 24 h. The mean tricuspid diastolic pressure gradient was calculated using the modified Bernoulli equation. Tricuspid valve area (TVA) was calculated by the pressure half-time method (TVA = 190 divided by pressure half-time). Data from Doppler echocardiography and cardiac catheterization were compared. The Doppler-derived tricuspid mean diastolic gradient was 1.9-9.9 mmHg (average 5.3 +/- 2.5 mmHg), which correlated moderately well with the catheterization-determined mean diastolic gradient of 2-17 mmHg (average 7.3 +/- 4.0 mmHg), R = 0.74, standard error of the estimate (SEE) 1.70 mmHg, Y = 0.45 x + 2.00, P less than 0.001. The Doppler-derived TVA was 0.56-1.58 cm2 (average 1.06 +/- 0.32 cm2), which correlated well with the catheterization-determined TVA of 0.4-2.2 cm2 (average 1.06 +/- 0.46 cm2), R = 0.81, SEE = 0.20 cm2, Y = 0.56 x + 0.46, P less than 0.001. Of 12 patients undergoing right ventricular angiography, the angiographic and Doppler grades of tricuspid regurgitation matched exactly in six and differed by one grade in the remaining six. This study demonstrated that Doppler echocardiography compares very well to cardiac catheterization in the quantification of tricuspid stenosis and in the assessment of concomitant tricuspid regurgitation.

Coronary artery disease, HDL cholesterol, and insulin-gene flanking sequences

The relationship between coronary artery disease, HDL cholesterol, and the hypervariable region flanking the human insulin gene was studied in Saudi Arabian non-diabetic subjects (n = 68) and in patients with Type 2 diabetes (n = 35). A locus of insulin-gene-linked DNA polymorphism with three average size classes of alleles was found: a small class 1, a rare medium size class 2, and a large class 3 allele. In the total group of subjects (n = 103), those with the class 3 allele had a lower plasma HDL cholesterol concentration than those without the class 3 allele (0.93 +/- 0.26 vs 1.12 +/- 0.30 mmol l-1, 2p less than 0.003). No difference in genotype and allelic frequency was found between patients with and without coronary artery disease in the combined group of subjects, with and without diabetes. Similarly the genotype distribution was not different between non-diabetic subjects and patients with Type 2 diabetes in the combined group of subjects, both with and without coronary artery disease. In conclusion, the study did not confirm a previous study showing an association between the class 3 allele and atherosclerosis in a Caucasian population. However, the class 3 allele was associated with a low plasma HDL cholesterol concentration.

Calcium-dependent proteolysis of actin during storage of platelet concentrates

In an ongoing study of the changes that occur in platelet concentrates during storage, we investigated two 28-26-Kd proteins designated SP-1 and SP-2, respectively, which increase markedly during blood-bank storage of platelet concentrates at room temperature. Formation of SP-1 and SP-2 was inhibited by storage at 4 degrees C as well as by treatment of the concentrates with leupeptin, N-ethylmaleimide, and EDTA; DFP and PPACK had no effect. The calcium ionophore A23187 markedly stimulated production of SP-1 and SP-2. After partial purification, the two proteins were found to be associated with platelet cytoskeletal protein. Two-dimensional peptide mapping and amino acid sequencing identified SP-1 and SP-2 as fragments of actin formed by cleavage on the N-terminal side of residues Thr-106 and Ala-114, respectively. Generation of SP-1 and SP-2 during storage of platelet concentrate is likely attributable to calcium-dependent neutral protease degradation of actin and may have implications for development of the platelet storage lesion.

Refractive-index measurements of the beta'' aluminas

The refractive indices of selected monovalent and divalent beta'' alumina single crystals are determined using prism refraction techniques. The birefringence is found to vary from uniaxial negative to uniaxial positive depending on the electronic polarizability of the exchanged ion. Thus, beta'' alumina is a novel material in which the magnitude and polarity of the birefringence can be tuned simply by ion exchange. The refractive-index data are used to predict an isoindex point (n(e) = n(0)) for the mixed-system Na(+)-Ag(+) beta'' alumina compositions.

The effect of histone gene deletions on chromatin structure in Saccharomyces cerevisiae

As a way of studying nucleosome assembly and maintenance in Saccharomyces cerevisiae, mutants bearing deletions or duplications of the genes encoding histones H2A and H2B were analyzed. Previous genetic analysis had shown that only one of these mutants exhibited dramatic and pleiotropic phenotypes. This mutant was also the only one that contained disrupted chromatin, suggesting that the original phenotypes were attributable to alterations in chromosome structure. The chromatin disruption in the mutant, however, did not extend over the entire genome, but rather was localized to specific regions. Thus, while the arrangement of nucleosomes over the HIS4 and GAL1 genes, the telomeres, and the long terminal repeats (delta sequences) of Ty retrotransposons appeared essentially normal, nucleosomes over the CYH2 and UBI4 genes and the centromere of chromosome III were dramatically disrupted. The observation that the mutant exhibited localized chromatin disruptions implies that the assembly or maintenance of nucleosomes differs over different parts of the yeast genome.