A method for isolation of sequences missing in one of two related genomes

We describe a novel technique for isolation of sequences that are present in one genome (tracer), but absent in another (driver). Tracer DNA, cleaved with Sau 3A and capped with a single stranded PCR adapter, is allowed to hybridize with an excess of sheared biotinylated driver; biotinylated DNA and its hybrids with the tracer are removed by phenol/chloroform extraction after incubation with streptavidin. After several rounds of subtraction the ends of self-annealed tracer molecules from the nonextractable fraction are filled-in with Tag polymerase and amplified, using the single stranded PCR adapter as a primer. The method has been applied to purification of fragments from a 2.9 kb plasmid added to E. coli DNA at equimolar quantity. Plasmid derived fragments (250-1000 bp), initially comprising 1/1400th part of tracer DNA, were purified to homogeneity after two rounds of subtraction followed by PCR.     

The appropriateness of use of percutaneous transluminal coronary angioplasty in New York State

Between 1974 and 1989 we prospectively observed 530 patients with brucellosis. The findings for 62 patients (42 males and 20 females; mean age, 34.7 years) with 63 episodes in which the sacroiliac joint was involved (the most frequent osteoarticular location [11.7%]) were analyzed. Ten of the older patients (mean age, 55.3 years) had concomitant spondylitis. Systemic symptoms were usually important, and characteristic pain and findings of sacroiliitis were observed in approximately 75% of cases. Blood cultures were positive for Brucella melitensis for 44 patients. The most frequent radiographic findings were blurring of articular margins (42 cases) and widening of the sacroiliac space (20 cases). No radiographic anomalies were detected in 13 cases. Results of 99mTc and gallium-67 bone scans were abnormal in approximately 90% of cases (abnormalities were often mild). Overall, clinical, radiographic, and isotopic bone scan findings were sensitive and useful, although they were occasionally minimal or difficult to evaluate, making diagnostic findings confusing or misleading. Brucellar sacroiliitis is a mild disease associated with a good outcome similar to that observed for patients with uncomplicated brucellosis.     

Integrated services for treatment of schizophrenic substance abusers: demographics, symptoms, and substance abuse patterns

We have previously described a model of outpatient integrated treatment for patients with comorbid psychoactive substance use disorders and schizophrenia (PSUD/S)(1). Here we review relevant literature on comorbidity and outline the rationale for integrated services. Further, we describe results from 3 related studies: First, we document the approximate incidence of PSUD among a heterogeneous group of 602 schizophrenic inpatient admissions to our hospital. Second, we describe in greater detail the psychiatric symptoms and patterns of substance abuse among a subsample of 106 inpatients with PSUD/S, contrasting them with 112 patients with PSUD and mixed psychotic disorders, but who are not schizophrenic. Third, we present a prospective research project and describe a sample of 30 patients with PSUD/S, detailing demographic characteristics, psychiatric symptoms and substance abuse history. Attention is given to current issues in the differential diagnosis of patients with PSUD/S using standardized instruments.     

The RSNA-AUR-ARRS introduction to research program for 2nd year radiology residents: effect on career choice and early academic performance. Radiological Society of North America. Association of University Radiologists. American Roentgen Ray Society

STUDY OBJECTIVE: To determine whether quantitative measurement of end-tidal carbon dioxide (ETCO2) can differentiate between cardiac and obstructive causes of respiratory distress. DESIGN: Prospective observational study. SETTING: Emergency department (ED) of a tertiary care hospital. PATIENTS: Adult patients who presented to the ED with moderate-to-severe dyspnea. Patients were excluded if they were unable to cooperate with the performance of peak expiratory flow rate (PEFR) or ETCO2 tests, were younger than 18 years of age, or had received prehospital intervention for their respiratory distress. INTERVENTIONS: Physicians obtained an ETCO2 level and PEFR prior to ED pharmacologic intervention. A hand-held capnometer with digital read-out was used to obtain the ETCO2 level. The patient's age, sex, initial vital signs, breath sounds and medication history, the presence or absence of diaphoresis and/or orthopnea, the duration of symptoms, the chest radiograph interpretation, and final diagnosis were also recorded. MEASUREMENTS and RESULTS: Forty-two patients were eligible for inclusion in the analysis. The mean ETCO2 level was 31.1+/-9.4 mm Hg; the mean PEFR was 161.3+/-53.1 L/min. The ETCO2 levels for pulmonary edema/congestive heart failure (CHF) patients differed significantly from those of asthma/COPD patients (27.1+/-7.8 mm Hg vs 33.4+/-9.6 mm Hg; p=0.0375). However, no single ETCO2 level was found to be a reliable predictor of diagnosis. CONCLUSION: ETCO2 levels for pulmonary edema/CHF patients differ significantly from those of asthma/COPD patients. However, no single ETCO2 level reliably differentiates between the two disease processes.     

Rolandic type cerebral palsy in children as a pattern of hypoxic-ischemic injury in the full-term neonate

Magnetic resonance images (MRIs) of the brains of 11 patients aged from 1 week to 12 years with a distinctive type of cerebral palsy were selected based on distribution of cerebral lesions, which were restricted to bilateral perirolandic cortical and subcortical regions, including frequent symmetric involvement of basal ganglia and ventrolateral nucleus of thalami. Retrospectively, the perinatal history and clinical features were reviewed to correlate clinical data with this distinctive pattern of brain injury. Clinically affected neonates had an encephalopathy associated with a severe perinatal asphyxial event. Older children with cerebral palsy survived a similar perinatal course and demonstrated spastic quadriparesis with bulbar or pseudobulbar involvement, lack of verbal speech and variable delays in cognitive development. The distribution of hypoxic-ischemic lesions involving bilateral perirolandic regions, basal ganglia, and thalami, appears to correlate with increased metabolic areas of primary myelination in full-term neonates, but not with arterial border zones nor a single cerebral artery distribution. Myelination is a critical process in maturing brain associated with marked increase in tissue respiration and thus greater susceptibility to oxygen deprivation. It is believed that the extent of hypoxic-ischemic brain injury is determined principally by brain maturity and regional metabolic rates at time of insult and this correlates with active myelination in full-term neonates. This study confirms previous data from neuropathologic literature and recent reports of neuroimaging studies of asphyxiated neonates. In addition, retrospective analysis of the clinical data enables recognition of a type of cerebral palsy that might be the hallmark of hypoxic-ischemic injury in term neonates.     

A prospective 12-year study of subsyndromal and syndromal depressive symptoms in unipolar major depressive disorders

BACKGROUND: Investigations of unipolar major depressive disorder (MDD) have focused primarily on major depressive episode remission/recovery and relapse/recurrence. This is the first prospective, naturalistic, long-term study of the weekly symptomatic course of MDD. METHODS: The weekly depressive symptoms of 431 patients with MDD seeking treatment at 5 academic centers were divided into 4 levels of severity: (1) depressive symptoms at the threshold for MDD; (2) depressive symptoms at the threshold for minor depressive or dysthymic disorder (MinD); (3) subsyndromal or subthreshold depressive symptoms (SSDs), below the thresholds for MinD and MDD; and (4) no depressive symptoms. The percentage of weeks at each level, number of changes in symptom level, and medication status were analyzed overall and for 3 subgroups defined by mood disorder history. RESULTS: Patients were symptomatically ill in 59% of weeks. Symptom levels changed frequently (1.8/y), and 9 of 10 patients spent weeks at 3 or 4 different levels during follow-up. The MinD (27%) and SSD (17%) symptom levels were more common than the MDD (15%) symptom level. Patients with double depression and recurrent depression had more chronic symptoms than patients with their first lifetime major depressive episode (72% and 65%, respectively, vs 46% of follow-up weeks). CONCLUSION: The long-term weekly course of unipolar MDD is dominated by prolonged symptomatic chronicity. Combined MinD and SSD level symptoms were about 3 times more common (43%) than MDD level symptoms (15%). The symptomatic course is dynamic and changeable, and MDD, MinD, and SSD symptom levels commonly alternate over time in the same patients as a symptomatic continuum of illness activity of a single clinical disease.     

Identification and characterization of the PutP proline permease that contributes to in vivo survival of Staphylococcus aureus in animal models

Staphylococcus aureus is an important pathogen of humans and other animals, causing bacteremia, abscesses, endocarditis, and other infectious syndromes. A signature-tagged mutagenesis (STM) system was adapted for use in studying the genes required for in vivo survival of S. aureus. An STM library was ultimately created in S. aureus RN6390, with Tn917 being used to create the transposon mutations. Pools of S. aureus RN6390 mutants were screened in mouse abscess, bacteremia, and wound infection models for growth attenuation after in vivo passage. One of the mutants that was identified displayed marked attenuation following large-pool screening in all three animal models, which was confirmed in bacteremia and endocarditis models of infection with a smaller pool of mutants. Sequence analysis of the entire open reading frame showed a 99% identity to the high-affinity proline permease (putP) gene characterized in another strain of S. aureus. In wound and murine abscess infection models, the putP mutant was approximately 10-fold more attenuated than was wild-type strain RN6390. Another S. aureus strain transduced with the putP mutation also displayed an attenuated phenotype after passage in the wound model. A [3H]proline uptake assay showed that less proline was specifically transported into the putP mutant than into strain RN6390. The reduced viability of the bacteria possessing the mutation in the S. aureus high-affinity proline permease suggests that proline scavenging by the bacteria is important for in vivo growth and proliferation and that analogs of proline may serve as potential antistaphylococcal therapeutic agents.