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Biomedical subjects

J Hammel

Publications and source records attributed to J Hammel.

At least 19 recordsLinked to original sources

Female bowel function: the real story.

PURPOSE: There has been minimal research done on normal female bowel habits. Because we do not know what is normal, this affects counseling of patients and research. The aim of this study was to conduct a survey of females with no bowel pathology to obtain a baseline of normal bowel function and examine any normal changes that occur during a woman's lifetime. METHODS: Females accompanying patients to our hospital and clinic were invited to fill out an IRB-approved questionnaire after excluding those with current bowel pathology, depression, a stoma, or were wheelchair bound. RESULTS: Four hundred twenty-five of 528 questionnaires of females who reported they had normal bowel habits were evaluated. The age range was from 18 to 80 years and comparison was according to age, race, and parity. Fifty-one percent had one bowel movement daily while 30 percent reported fewer. Overall, 15 percent reported constipation, which was higher in African-American females (26 percent) vs. Caucasian females (14 percent), P = 0.08. The average time for a bowel movement was 5-6 minutes, which was longer in African-American females (7.7 min) vs. Caucasian (5.0 min), P = 0.002. Younger females had changes in their bowel pattern reported as soft stool usually associated with their menstrual cycle; this was seen mostly in single females. Menopause did not affect bowels. Thirty-six percent of parous females reported occasional stool incontinence. Flatal incontinence was seen occasionally in over 50 percent of females, more frequently in those over 35 years old. Seventy-four percent of parous females reported incontinence to gas. One-third of females read on the toilet, with a majority doing so to relax or to be distracted and with African-American females reading more (54 percent) vs. Caucasian (32 percent), P = 0.004. Interestingly, Caucasian females read to conserve time (26 percent) vs. African-Americans (4 percent), P = 0.02. Fiber as a supplement was taken by only 8 percent. Foods affected bowel function in all age groups, while travel and exercise did not. Stress affected a change in 35 percent in the 18 to 50-year group. CONCLUSION: There is a vast diversity in what is considered normal female bowel habits. One daily bowel movement is not the norm. Normal older females and those who have had children report more flatal incontinence. One-third experience some element of fecal incontinence. Foods most commonly caused a change in bowel pattern, followed by menstruation, stress, and childbirth. A vast majority do not take fiber as a supplement.

Adolescent↗

Long-term outcome after laparoscopic and open surgery for rectal prolapse: a case-control study.

BACKGROUND: Laparoscopic repair (LR) of rectal prolapse is potentially associated with earlier recovery and lower perioperative morbidity, as compared with open transabdominal repair (OR). Data on the long-term recurrence rate and functional outcome are limited. METHODS: Perioperative data on rectal prolapse in relation to all LRs performed between December 1991 and April 2004 were prospectively collected. The LR patients were matched by age, gender, and procedure type with OR patients who underwent surgery during the same period. Patients with previous complex abdominal surgery or a body mass index exceeding 40 were excluded from the study. Data on recurrence rate, bowel habits, continence, and satisfaction scores were collected using a telephone survey. RESULTS: A total of 111 patients (age, 56.8 +/- 18.1 years; female, 87%) underwent attempted LR. An operative complication deferred repair in two cases. Among the 111 patients, 42 had posterior mesh fixation, and 67 had sutured rectopexy (32 patients with sigmoid colectomy for constipation). Eight patients (7.2%) had conversion to laparotomy. Matching was established for 86 patients. The LR patients had a shorter hospital stay (mean, 3.9 vs 6.0 days; p < 0.0001). The 30-day reoperation and readmission rates were similar for the two groups. The rates for recurrence requiring surgery were 9.3% for LR and 4.7% for OR (p = 0.39) during a mean follow-up period of 59 months. An additional seven patients in each group reported possible recurrence by telephone. Postoperatively, 35% of the LR patients and 53% of the OR patients experienced constipation (p = 0.09). Constipation was improved in 74% of the LR patients and 54% of the OR patients, and worsened, respectively, in 3% and 17% (p = 0.037). The postoperative incontinence rates were 30% for LR and 33% for OR (p = 0.83). Continence was improved in 48% of the LR patients and 35% of the OR patients, and worsened, respectively, in 9% and 18% (p = 0.22). The mean satisfaction rates for surgery (on a scale of 0 to 10) were 7.3 for the LR patients and 8.1 for the OR patients (p = 0.17). CONCLUSIONS: The hospital stay is shorter for LR than for OR. Both functional results and recurrent full-thickness rectal prolapse were similar for LR and OR during a mean follow-up period of 5 years.

Abdomen↗

The localizing value of ictal EEG in focal epilepsy.

OBJECTIVE: To investigate the lateralization and localization of ictal EEG in focal epilepsy. METHODS: A total of 486 ictal EEG of 72 patients with focal epilepsy arising from the mesial temporal, neocortical temporal, mesial frontal, dorsolateral frontal, parietal, and occipital regions were analyzed. RESULTS: Surface ictal EEG was adequately localized in 72% of cases, more often in temporal than extratemporal epilepsy. Localized ictal onsets were seen in 57% of seizures and were most common in mesial temporal lobe epilepsy (MTLE), lateral frontal lobe epilepsy (LFLE), and parietal lobe epilepsy, whereas lateralized onsets predominated in neocortical temporal lobe epilepsy and generalized onsets in mesial frontal lobe epilepsy (MFLE) and occipital lobe epilepsy. Approximately two-thirds of seizures were localized, 22% generalized, 4% lateralized, and 6% mislocalized/lateralized. False localization/lateralization occurred in 28% of occipital and 16% of parietal seizures. Rhythmic temporal theta at ictal onset was seen exclusively in temporal lobe seizures, whereas localized repetitive epileptiform activity was highly predictive of LFLE. Seizures arising from the lateral convexity and mesial regions were differentiated by a high incidence of repetitive epileptiform activity at ictal onset in the former and rhythmic theta activity in the latter. CONCLUSIONS: With the exception of mesial frontal lobe epilepsy, ictal recordings are very useful in the localization/lateralization of focal seizures. Some patterns are highly accurate in localizing the epileptogenic lobe. One limitation of ictal EEG is the potential for false localization/lateralization in occipital and parietal lobe epilepsies.

Adolescent↗

Alterations in exhaled gas profile during allergen-induced asthmatic response.

The source of exhaled carbon monoxide (CO) and the relationship to airway inflammation are not clear. If CO is produced by the inflamed airway, we hypothesized that inflammation induced by allergen challenge would increase exhaled CO of atopic asthmatics. Eight atopic asthmatics underwent whole lung allergen challenge. CO, nitric oxide (NO), oxygen, and carbon dioxide (CO(2)) were measured simultaneously in exhaled breath which was collected into Mylar balloons before (baseline), immediately after, and at subsequent times after allergen. NO was higher in asthmatics than control subjects at baseline, increased further in seven of the eight asthmatics after allergen, and was inversely correlated to specific conductance. In contrast, exhaled CO of asthmatics was not higher than that of control individuals at baseline, decreased immediately after allergen, and returned to baseline levels during the late asthmatic response. Thus, allergen-induced airway inflammation did not lead to increased exhaled CO in asthma.

Adult↗

NO chemical events in the human airway during the immediate and late antigen-induced asthmatic response.

A wealth of evidence supports increased NO (NO.) in asthma, but its roles are unknown. To investigate how NO participates in inflammatory airway events in asthma, we measured NO. and NO. chemical reaction products [nitrite, nitrate, S-nitrosothiols (SNO), and nitrotyrosine] before, immediately and 48 h after bronchoscopic antigen (Ag) challenge of the peripheral airways in atopic asthmatic individuals and nonatopic healthy controls. Strikingly, NO(3)(-) was the only NO. derivative to increase during the immediate Ag-induced asthmatic response and continued to increase over 2-fold at 48 h after Ag challenge in contrast to controls [P < 0.05]. NO(2)(-) was not affected by Ag challenge at 10 min or 48 h after Ag challenge. Although SNO was not detectable in asthmatic airways at baseline or immediately after Ag, SNO increased during the late response to levels found in healthy controls. A model of NO. dynamics derived from the current findings predicts that NO. may have harmful effects through formation of peroxynitrite, but also subserves an antioxidant role by consuming reactive oxygen species during the immediate asthmatic response, whereas nitrosylation during the late asthmatic response generates SNO, safe reservoirs for removal of toxic NO. derivatives.

Adult↗

Repair of recurrent rectovaginal fistulas.

BACKGROUND: Recurrent rectovaginal fistulas (RRVFs) pose a challenging problem, which can be treated by different surgical procedures. We performed this study to determine the ultimate success rate of various repair techniques. METHODS: Using a standard data collection form, we retrospectively reviewed charts of patients treated for RRVF. RESULTS: Between 1991 and 2000, 57 procedures were performed in 35 women who presented with RRVF. Median follow-up was 4 months (interquartile range, 1,25). The causes of RRVF included obstetrical injury (n = 15), Crohn's disease (n = 12), fistula occurring after proctocolectomy with ileal pouch-anal anastomosis (for ulcerative colitis, n = 3; indeterminate colitis, n = 1; familial polyposis, n = 1), cryptoglandular disease (n = 2), and fistula occurring immediately after low anterior resection for rectal cancer (n = 1). The methods of repair used included mucosal advancement flap (n = 30), fistulotomy with overlapping sphincter repair (n = 14), rectal sleeve advancement (n = 3), fibrin glue (n = 1), proctectomy with colonic pull-through (n = 2), and ileal pouch revision (n = 6). Twenty-seven of 34 (79%) patients with adequate follow-up eventually healed after a median of 2 operations. Logistic regression was used to analyze outcome according to etiology of fistula, patient age, number of prior repairs, time interval between last repair and current repair, and presence of fecal diversion. Crohn's disease, the presence of a diverting stoma, and decreased time interval since prior repair were associated with a poorer outcome. CONCLUSIONS: Most RRVFs can be successfully repaired, although repeated operations may be necessary. Delaying repair may improve outcome.

Adult↗

Development, analysis, refinement, and utility of an interdisciplinary amyotrophic lateral sclerosis database.

The current status of evaluation and management provided by individual healthcare professionals (HCP) at amyotrophic lateral sclerosis (ALS) centers and clinics needs to be analyzed. This paper describes one ALS center's experiences with the development, analysis, refinement, and utility of an interdisciplinary, HCP-driven ALS database. The purpose and conceptual framework of the database, the general data that needed to be collected, and the types of reports that needed to be generated were determined, and, in collaboration with a computer programmer, data entry and database management systems were developed. Data were collected on 234 patients between September 1996 and August 1998, and were analyzed by a biostatistician. Based on review of the biostatistician's report and discussion of problems encountered with the systems, the database was then refined. Benefits of the database system included: systematization of data collection and reporting, reduction of redundant data collection by individuals, decreased variability of evaluation methods and management decisions from patient to patient, and increased availability of a variety of uniform patient information to assist team members in making care decisions. Ongoing refinement will ensure that this HCP-driven ALS database continues to be informative, practical and effective for decision-making and enhancing delivery of care.

Adult↗

Privately funded quality health care in India: a sustainable and equitable model.

OBJECTIVE: As the cost and degree of training necessary to provide state of the art health care has increased throughout the world, the present challenge in health care is to establish institutions that are financially sound and responsive to the dynamic needs of the communities in which they exist. As public funds have diminished, the role of the private sector in estabhshing innovative health care institutions has increased. SETTING AND STUDY PARTICIPANTS: This paper reviews the case of the LV Prasad Eye Institute (LVPEI), an ophthalmologic institute in Hyderabad, India, that is financially sound and medically vital. With an annual budget of US$3 million, 180 000 patients are seen and 23 000 surgeries are performed at the Institute and its satellites each year. MAIN MEASURES: The Institute provides patient care at a ratio of 1:1 non-paying to paying patients through fee cross-subsidization. The Institute uses a combination of financial modalities, including donations, grants and fees to administer its non-patient care programs. Non-clinical programs of the Institute include a paramedical training program and a fellowship in ophthalmology, an internationally accredited eye bank for the preservation of corneal tissues, a rural out-reach and education program, a basic science and epidemiology program that directs health policy activities of the Institute and a rehabilitation program for patients with incurable visual deficits. To evaluate its effectiveness, LVPEI uses quality improvement measures, including patient surveys, post-operative outcomes studies and service utlization reviews. CONCLUSION: This case report of a privately-funded medical institution describes a successful model through which high-quality, equitable health care can be provided in a developing country. The LVPEI's active program of quality management, its academic commitment and programmatic relevance to the needs of its community should be modularized and replicated to establish equitable, efficient and effective health care institutions in the developing world.

Budgets↗

Analysis of risk factors for myocardial infarction and cardiac mortality after major vascular surgery.

BACKGROUND: Patients undergoing vascular surgical procedures are at high risk for perioperative myocardial infarction (PMI). This study was undertaken to identify predictors of PMI and in-hospital death in major vascular surgical patients. METHODS: From the Vascular Surgery Registry (6,948 operations from January 1989 through June 1997) the authors identified 107 patients in whom PMI developed during the same hospital stay. Case-control patients (patients without PMI) were matched at a 1x:x1 ratio with index cases according to the type of surgery, gender, patient age, and year of surgery. The authors analyzed data regarding preoperative cardiac disease and surgical and anesthetic factors to study association with PMI and cardiac death. RESULTS: By using univariable analysis the authors identified the following predictors of PMI: valvular disease (P = 0.007), previous congestive heart failure (P = 0.04), emergency surgery (P = 0.02), general anesthesia (P = 0.03), preoperative history of coronary artery disease (P = 0.001), preoperative treatment with beta-blockers (P = 0.003), lower preoperative (P = 0.03) and postoperative (P = 0.002) hemoglobin concentrations, increased bleeding rate (as assessed from increased cell salvage; P = 0.025), and lower ejection fraction (P = 0.02). Of the 107 patients with PMI, 20.6% died of cardiac cause during the same hospital stay. The following factors increased the odds ratios for cardiac death: age (P = 0.001), recent congestive heart failure (P = 0.01), type of surgery (P = 0.04), emergency surgery (P = 0.02), lower intraoperative diastolic blood pressure (P = 0.001), new intraoperative ST-T changes (P = 0.01), and increased intraoperative use of blood (P = 0.005). Patients who underwent coronary artery bypass grafting, even more than 12 months before index surgery, had a 79% reduction in risk of death if they had PMI (P = 0.01). Multivariable analysis revealed preoperative definitive diagnosis of coronary artery disease (P = 0.001) and significant valvular disease (P = 0.03) were associated with increased risk of PMI. Congestive heart failure less than 1 yr before index vascular surgery (P = 0. 0002) and increased intraoperative use of blood (P = 0.007) were associated with cardiac death. The history of coronary artery bypass grafting reduced the risk of cardiac death (P = 0.04) in patients with PMI. CONCLUSIONS: The in-hospital cardiac mortality rate is high for patients who undergo vascular surgery and experience clinically significant PMI. Stress of surgery (increased intraoperative bleeding and aortic, peripheral vascular, and emergency surgery), poor preoperative cardiac functional status (congestive heart failure, lower ejection fraction, diagnosis of coronary artery disease), and preoperative history of coronary artery bypass grafting are the factors that determine perioperative cardiac morbidity and mortality rates.

Analysis of Variance↗

Coronary artery stent restenosis responds favorably to repeat interventions.

One hundred sixty patients who underwent a percutaneous intervention for treatment of in-stent restenosis were evaluated on clinical follow-up to determine the predictors of reintervention, and also to compare rotational atherectomy with repeat percutaneous transluminal coronary angioplasty (PTCA) for this condition. Current smoking and saphenous vein graft location were the independent predictors of target vessel revascularization (TVR), and there was no difference in the rate of TVR between rotational atherectomy and re-PTCA.

Angioplasty, Balloon, Coronary↗

Nitric oxide regulation of asthmatic airway inflammation with segmental allergen challenge.

BACKGROUND: Despite evidence of increased nitric oxide (NO) in asthmatic compared with healthy individuals, the role of NO in airway inflammation is unclear. OBJECTIVE: The purpose of the study was to determine the in vivo effects of localized allergen challenge on airway NO levels and transcription factor activation. METHODS: In this study localized allergen challenge was used as a model of asthmatic exacerbation to determine the relationship of NO to airway inflammation. RESULTS: With allergen challenge, asthmatic patients had a rise in airway NO levels, whereas NO levels in healthy controls did not change. The increased NO in asthma with allergen challenge compared with healthy control subjects was associated with an increase in inflammatory cytokines (GM-CSF and macrophage inflammatory protein-1) in epithelial lining fluid and eosinophilic infiltrate in bronchoalveolar lavage fluid (BAL) and biopsy specimens. To investigate the mechanisms of cytokine gene expression, activation of the transcription factors activator protein-1 and nuclear factor-kappaB (NF-kappaB) in cells from BAL were evaluated. Activator protein-1 was not activated before or after local allergen challenge. In contrast, NF-kappaB activation was less in BAL cells from asthmatic patients with increased NO in comparison with controls. CONCLUSION: Our studies are the first to suggest an inverse correlation between NF-kappaB and airway NO in a localized segmental allergen challenge model in allergic asthmatic patients. The current study demonstrates that activation of the inflammatory response (eg, cytokines, cellular infiltrate) in allergic asthmatic patients is temporally associated with increased airway NO. We propose that NO that is up-regulated by cytokines is part of an autoregulatory feedback loop (ie, allergen challenge stimulates inflammatory cytokine production, which in turn stimulates NO production, and NO down-regulates cytokine production).

Adult↗

Predicting the difficult neuraxial block: a prospective study.

UNLABELLED: Anticipated technical difficulty is one factor that can influence the anesthesiologist's decision to perform neuraxial (spinal or epidural) blockade. Problems during the procedure may be associated with patient dissatisfaction, neurologic sequelae, or hematoma. We designed this study of 595 neuraxial blocks to determine whether any patient characteristics would be useful in predicting a difficult neuraxial block. Before the procedure, the following data were noted: demographic data, body habitus (normal, thin, muscular, obese), spinal landmarks (good = easily palpable spinous processes, poor = difficult to palpate spinous processes, none = unable to positively identify spinous processes), and spinal anatomy (assessed by inspection and examination as normal or deformed). We noted the technique, approach, needle type, needle gauge, etc. We also recorded whether the procedure was completed at the first (first-level success) or second spinal level and the total number of new skin punctures (attempts) necessary to complete the procedure. Of all the factors considered, the quality of landmarks best correlated with technical difficulty as measured by both first-level success and number of attempts. Abnormal spinal anatomy correlated with difficulty as measured by number of attempts. Body habitus also correlated with difficulty, but only as measured by number of attempts. There was no association between either measure of difficulty and any of the following: age, sex, spinal versus epidural, approach, needle type, needle gauge, or training level of the provider. Thoracic epidurals were less difficult than lumbar epidurals by both measures of difficulty. We conclude that body habitus does not seem to be the best predictor of technical difficulty. An examination of the patient's back for the quality of landmarks and obvious anatomical deformity better predicts the ease or difficulty of neuraxial block. Other factors seem to have little or no influence on the difficulty of neuraxial block procedures. IMPLICATIONS: We studied a number of factors, including equipment, technique, and patient characteristics, that may indicate the ease or difficulty of performing neuraxial (spinal and epidural) blocks. Of these factors, only patient characteristics had significant predictive value. We found that an examination of the patient's back for the quality of landmarks and obvious anatomical deformity better predicts the ease or difficulty of neuraxial block than does body habitus.

Adolescent↗

Agreement and clinical utility of 2 techniques for measuring cardiac output in patients with low cardiac output.

BACKGROUND: The reliability of cardiac output obtained with the bolus technique is a problem. OBJECTIVES: To compare measurements of cardiac output measured with bolus and continuous techniques in patients with low cardiac output and to determine if measurements obtained with the continuous technique increased the number of subsequent clinical decisions. METHODS: In 60 intensive care patients, a nurse recorded a single continuous cardiac output measurement and then obtained the mean of 3 consecutive bolus determinations. The medical records of these 60 patients (experimental group) for the next 48 hours and of 60 other patients with regular or mixed venous oximetry catheters (control group) were reviewed to assess the occurrence of cardiac output events and the frequency of clinical decisions based on the events. RESULTS: Mean cardiac output was 4.46 L/min by the continuous technique and 5.20 L/min by the bolus technique (P = .011) for the experimental group. Median bias between the 2 types of measurements was -0.10 L/min (P = .79). Twenty-three of the pairs (38%) had an absolute percent difference greater than 15%. Of these, 18 (78%) had a higher bolus reading. Treatment decisions per 48 hours were 9.9 for the experimental group and 8.6 for the control group (P = .014). Median length of stay was 2 days less in the experimental group (P = .02), and mean highest cardiac output was 0.81 L/min higher (P = .009). CONCLUSIONS: Measurements of cardiac output determined with the continuous technique may be more precise than measurements determined with the bolus technique. Continuous cardiac output information increases the number of treatment decisions and actions that may shorten hospital length of stay.

Cardiac Output↗

Low-dose aspirin for oocyte donation recipients with a thin endometrium: prospective, randomized study.

OBJECTIVE: To evaluate the effect of low-dose aspirin use in oocyte donation recipients with an endometrial thickness of < 8 mm. DESIGN: A prospective, randomized study. SETTING: An oocyte donation program in a private infertility practice. PATIENT(S): Twenty-eight recipients undergoing oocyte donation who failed to develop an endometrial thickness of at least 8 mm in a previous evaluation cycle. INTERVENTION(S): Fifteen recipients received low-dose aspirin (81 mg/d) in addition to standard hormone replacement for an oocyte donation cycle. The remaining 13 recipients did not receive aspirin. MAIN OUTCOME MEASURE(S): Clinical pregnancy rates, delivery rates, implantation rates, and change in endometrial thickness were compared in the aspirin and nonaspirin groups. RESULT(S): There was no demonstrable increase in endometrial thickness in the aspirin-treated group. However, there was a statistically significant increase in implantation rates in the aspirin-treated group (24% versus 9%) and in implantation rates and clinical pregnancy rates in the aspirin-treated group when the final endometrial thickness was < 8 mm. CONCLUSION(S): Low-dose aspirin therapy improves implantation rates in oocyte donation recipients with a thin endometrium.

Adult↗

Clinical and electrographic manifestations of lesional neocortical temporal lobe epilepsy.

To determine whether lesional neocortical temporal lobe epilepsy (NTLE) can be differentiated from mesial temporal lobe epilepsy (MTLE) during the noninvasive presurgical evaluation, we compared the historical features, seizure symptomatology, and surface EEG of 8 patients seizure free after neocortical temporal resection with preservation of mesial structures and 20 patients after anterior temporal lobectomy for MTLE. Seizure symptomatology of 107 seizures (28 NTLE, 79 MTLE) was analyzed. One hundred one ictal EEGs (19 NTLE, 82 MTLE) were reviewed for activity at seizure onset; presence, distribution, and frequency of lateralized rhythmic activity (LRA); and distribution of postictal slowing. Seizure symptomatology and EEG data were compared between groups, and sensitivity, specificity, and positive and negative predictive values were determined for variables that differed significantly. Multiple logistic regression was used to determine whether patients could be correctly classified as having MTLE or NTLE. MTLE patients were younger at onset of habitual seizures and more likely to have a prior history of febrile seizures, CNS infection, perinatal complications, or head injury. NTLE seizures lacked features commonly exhibited in MTLE, including automatisms, contralateral dystonia, searching head movements, body shifting, hyperventilation, and postictal cough or sigh. NTLE ictal EEG recordings demonstrated lower mean frequency of LRA that frequently had a hemispheric distribution, whereas LRA in MTLE seizures was maximal over the ipsilateral temporal region. We conclude that it may be possible to differentiate lesional NTLE from MTLE on the basis of historical features, seizure symptomatology, and ictal surface EEG recordings. This may assist in the identification of patients with medically refractory nonlesional NTLE who frequently require intracranial monitoring and more extensive or tailored resections.

Adult↗

Technology competencies for occupational therapy practitioners.

A task force has created a recommended set of technology competencies for occupational therapy practitioners at three levels of practice: entry/basic, intermediate, and advanced. The competencies relate to assistive technology (AT) evaluation, intervention, and resource coordination and reflect minimum knowledge and skills for registered occupational therapists (O.T.R.'s) and certified occupational therapy assistants (C.O.T.A.'s). The competencies were reviewed by members of the American Occupational Therapy Association (AOTA), the COTA network and RESNA, and were coordinated with RESNA's ongoing AT quality assurance and certification efforts. They represent a base for the component of outcome management related to ensuring the quality and competency of AT service deliverers.

Certification↗

Splicing function of mammalian U6 small nuclear RNA: conserved positions in central domain and helix I are essential during the first and second step of pre-mRNA splicing.

On the basis of mutational analyses in yeast, the highly conserved ACAGAGA sequence of U6 small nuclear RNA (snRNA) and the adjacent U6-U2 helix I have been proposed to be part of the active center of the spliceosome. We report here a detailed analysis of the human U6 snRNA sequence requirements during the first and second step of splicing, using a mammalian in vitro splicing-complementation system and a mutational approach. Positions A53G54C55 (helix Ib) were identified as important specifically for the first step, but not for spliceosome assembly. A45 of the ACAGAGA sequence and U52 of helix Ia function during the second step; in addition, the bulge separating helices Ia and Ib appears critical for the second step. In contrast, no splicing-essential sequences could be identified in the central domain upstream of the ACAGAGA sequence. In sum, our data demonstrate for the mammalian splicing system that discrete positions within the ACAGAGA sequence and helix I of U6 snRNA function during the first and second step of splicing, suggesting that these two sequence elements are closely associated with the catalytic center of the spliceosome. Comparison with previous results in yeast indicates a fundamental conservation of the U6 snRNA function in the pre-mRNA splicing mechanism.

Base Sequence↗

Use of adjunctive modalities in occupational therapy.

This article reminds us that as practice evolves, we must revisit and reaffirm the fundamental philosophy and precepts in which our profession is grounded. The face of practice is fluid. Its superficial appearance is molded by external forces and stresses. These include the changes in the needs of the persons we serve, the emergence of new and different treatment modalities, and the realities of the socioeconomic environment in which we work. Beneath the surface, however, are the basic structures that all of us hold in common. These are our philosophical beliefs that are articulated both in the professional literature and in the ethical principles that we espouse.

Combined Modality Therapy↗