African American antiplatelet stroke prevention study: Clinical trial design

BACKGROUND AND PURPOSE

African Americans are about two times more likely than European Americans to die of cerebrovascular disease or to experience stroke. Although this disparity exists, African Americans have been underrepresented in clinical trials. The African American Antiplatelet Stroke Prevention Study (AAASPS) is a multi-center, randomized, double-blind, clinical trial to compare the effect of ticlopidine and aspirin in the prevention of recurrent stroke, myocardial infarction, and vascular death in African Americans with recent, noncardioembolic ischemic stroke.

TRIAL DESIGN

There will be 1,800 African American noncardioembolic ischemic stroke patients at 40 sites nationally randomized to receive ticlopidine (500 mg/d) or aspirin (650 mg/d) at least 7 days but no more than 90 days after the qualifying event. Complete blood count and platelet count are monitored every 2 weeks during the first 3 months of active treatment to monitor for neutropenia and thrombocytopenia. Patients with transient cerebral ischemia, recent active peptic ulcer disease or lower gastrointestinal bleeding, bleeding diathesis, and women of childbearing potential are excluded. Study patients will be followed-up for a total of 2 years for occurrence of the primary outcome endpoint cluster of recurrent stroke, myocardial infarction, and vascular death. Safety analyses will focus on the incidence of severe adverse events such as neutropenia, thrombocytopenia, gastrointestinal bleeding, and liver dysfunction. Analyses for key endpoints will use the intention-to-treat principle and time-to-event data will be analyzed using Mantel-Haenszel and various regression methods.

CONCLUSION

African Americans have a survival disadvantage that substantially relates to the occurrence of stroke. AAASPS is the first secondary stroke prevention study exclusively for African Americans and promises to provide important information to guide recurrent stroke prevention treatment for this high-risk group.

Phase I/II trial of the safety and efficacy of shark cartilage in the treatment of advanced cancer

PURPOSE

Patients with cancer and chronic inflammatory disorders have used shark cartilage (SC) preparations for many years. Preclinical studies that support their beneficial effects are scanty, and reports of clinical trials have been anecdotal. The proposed mechanisms of antitumor action include direct or indirect inhibition of angiogenesis. Because of the emerging use of SC as an alternative to conventional cancer therapy, this trial was launched to evaluate the safety and efficacy of SC.

PATIENTS AND METHODS

Sixty adult patients with advanced previously treated cancer (breast, 16 patients; colorectal, 16 patients; lung, 14 patients; prostate, eight patients; non-Hodgkin lymphoma, three patients; brain, one patient; and unknown primary tumor, two patients) were enrolled. Eligibility criteria included confirmation of diagnosis, resistance to conventional therapy, objective measurable disease, life expectancy of 12 weeks or greater, Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2, no recent or concomitant anticancer therapy, no prior SC, and informed consent. Patients underwent evaluation of the extent of disease, quality-of-life score (Functional Assessment of Cancer Therapy-General [FACT-G] scale), and hematologic, biochemical, and selected immune function studies at baseline and after 6 and 12 weeks of SC therapy. The dose of SC was 1 g/kg daily orally in three divided doses. Standard criteria were used to evaluate adverse events and response.

RESULTS

Ten of 60 patients were lost to follow-up(LTFU) or refused further treatment (RFT) before the 6-week evaluation and were not assessable for toxicity and response. Three patients with stable disease at 6 weeks were LTFU or RFT thereafter. Of the 47 fully assessable patients, five were taken off study because of gastrointestinal toxicity or intolerance to SC. Progressive disease (PD) at 6 or 12 weeks occurred in 22 and five patients, respectively. Five patients died of PD while undergoing SC therapy. No complete (CRs) or partial responses (PRs) were noted. Median time to tumor progression in the entire study population was 7+/-9.7 weeks (mean, 11.4 weeks; range, 3.7 to 45.7 weeks). Ten (20%) of 50 assessable patients, or 16.7% of the 60 intent-to-treat patients, had stable disease (SD) for 12 weeks or more. The median time to tumor progression was 27 weeks, the mean was 28.8+/-9.9 weeks, and the range was 18.6 to 45.7 weeks. In this subset, FACT-G scores improved in four patients, were unchanged in four patients, and declined in two patients. Twenty-one adverse events (grade 1, eight events; grade 2, seven events; and grade 3, six events) were recorded, 14 of which were gastroenterologic (nausea, vomiting, constipation).

CONCLUSION

Under the specific conditions of this study, SC as a single agent was inactive in patients with advanced-stage cancer and had no salutary effect on quality of life. The 16.7% rate of SD was similar to results in patients with advanced cancer treated with supportive care alone.

Adult respiratory distress syndrome after microvascular free tissue reconstruction in head and neck malignancy

Adult respiratory distress syndrome (ARDS) is an important cause of morbidity and mortality after major operations. We undertook a 10 year retrospective analysis of patients undergoing major surgery in combination with microvascular free tissue transfer for head and neck malignancy at a Regional Maxillofacial Unit to try and identify predisposing factors. In the 10 year period to 31 April 1995, roughly 418 patients underwent major head and neck reconstructions, of which 399 (95.5%) were admitted to the intensive care unit (ICU) postoperatively. Thirty patients (7.2%) spent more than 72 h in the ICU, eight developed ARDS (1.9%) of whom four died. The factors that seemed to contribute to the development of ARDS were massive blood transfusion and early postoperative complications that required a further operation under general anaesthesia.

Complete genome sequence of Treponema pallidum, the syphilis spirochete

The complete genome sequence of Treponema pallidum was determined and shown to be 1,138,006 base pairs containing 1041 predicted coding sequences (open reading frames). Systems for DNA replication, transcription, translation, and repair are intact, but catabolic and biosynthetic activities are minimized. The number of identifiable transporters is small, and no phosphoenolpyruvate:phosphotransferase carbohydrate transporters were found. Potential virulence factors include a family of 12 potential membrane proteins and several putative hemolysins. Comparison of the T. pallidum genome sequence with that of another pathogenic spirochete, Borrelia burgdorferi, the agent of Lyme disease, identified unique and common genes and substantiates the considerable diversity observed among pathogenic spirochetes.

Continuous venovenous high-flux dialysis in multiorgan failure: a 5-year single-center experience

The objective of this study was to determine the outcome of acute renal failure (ARF) treated by continuous venovenous high-flux dialysis in patients with ventilator-dependent respiratory failure treated in a single center and to examine the importance of primary diagnosis in determining survival. We retrospectively reviewed 408 consecutively treated patients in the multidisciplinary intensive care unit (ICU) of a large teaching hospital. All ventilated patients requiring dialysis support over a 5-year period (January 1, 1991 to December 31, 1995) were included in the study. Patient age, APACHE II score, primary diagnosis, inotrope requirement, and survival to discharge from the ICU, from the hospital, and at 6 months were recorded for 408 consecutively treated patients. The mean age was 54 years, the median APACHE II score was 29, and the ICUs, hospital, and 6-month survival rates were 48%, 38%, and 36%, respectively. Inotropic support was required in 75%. Liver disease was the primary diagnosis in 35%. Logistic regression analysis indicated that increasing age and APACHE II, use of inotropes, and presence of liver disease were all associated with increased mortality. Eight percent of survivors (3% of the total population) required long-term renal replacement therapy. In conclusion, in our experience, continuous venovenous high-flux dialysis can be universally adopted in the ICU management of ARF associated with multiorgan failure. Patient survival is related to primary diagnosis, and a knowledge of case mix is essential in considering outcome of ARF in any reported series.

No relationship between emergency department activity and triage categorization

OBJECTIVE

To examine the consistency of Australasian National Triage Scale (NTS) categorization in a large hospital ED, especially in relation to daily activity.

METHODS

This was a prospective, observational study of the relationship between NTS category, presenting features, and disposition in a large Australian adult ED. The "admission rate" was defined as the percentage of presentations whose dispositions were recorded as admitted to hospital, transferred to another hospital for admission, or died in the ED. A "busy" weekday was defined as one during which > 140 presentations were recorded in the 24 hours from midnight. For a "busy" weekend day, a figure of 100 presentations in 24 hours was used. "Nonbusy" days were defined as those during which presentation numbers were less than or equal to these thresholds.

RESULTS

Data describing triage and disposition were available for 94,681 presentations in the 2-year period, representing 100% of ED presentations. "Busy" weekday admission rates in the 5 triage categories were 93.2%, 67.6%, 43.6%, 15.4%, and 1.6%, respectively. "Nonbusy" weekday admission rates were 91.4%, 68.3%, 43.7%, 15.6%, and 2.0%. Weekend days had a higher admission rate in NTS category 4 and 5 patients, but none of the differences between "busy" and "nonbusy" days reached statistical significance at the 0.05 level. Admission rates varied according to the time of day of presentation and increased with age, but did not change significantly over the 2 years of the study.

CONCLUSIONS

In this ED, triage categorization according to the Australasian NTS does not vary with daily activity and has been consistent over time. Further study in other settings is required, particularly to identify variation dependent on the presenting population.

Race and the risk of fatal injury at work

OBJECTIVES

This study examined employment patterns of African-American and White workers and rates of unintentional fatal injuries,

METHODS

Medical examiner and census data were used to compare occupational fatality rates for African Americans and Whites in North Carolina and to adjust for racial differences in employment patterns.

RESULTS

African Americans' occupational fatality rate was higher by a factor of 1.3 to 1.5. Differences in employment structure appear to explain much of this disparity. However, the fatality rate for African-American men would have been elevated even if they had had the same employment patterns as White men.

CONCLUSIONS

inequalities in access to the labor market, unequal distribution of risk within jobs, and explicit discrimination are all potential explanations for racial disparities in occupational injury mortality. These conditions can be addressed through a combination of social and workplace interventions, including efforts to improve conditions for the most disadvantaged workers.

Genomic sequence of a Lyme disease spirochaete, Borrelia burgdorferi

The genome of the bacterium Borrelia burgdorferi B31, the aetiologic agent of Lyme disease, contains a linear chromosome of 910,725 base pairs and at least 17 linear and circular plasmids with a combined size of more than 533,000 base pairs. The chromosome contains 853 genes encoding a basic set of proteins for DNA replication, transcription, translation, solute transport and energy metabolism, but, like Mycoplasma genitalium, it contains no genes for cellular biosynthetic reactions. Because B. burgdorferi and M. genitalium are distantly related eubacteria, we suggest that their limited metabolic capacities reflect convergent evolution by gene loss from more metabolically competent progenitors. Of 430 genes on 11 plasmids, most have no known biological function; 39% of plasmid genes are paralogues that form 47 gene families. The biological significance of the multiple plasmid-encoded genes is not clear, although they may be involved in antigenic variation or immune evasion.

Student perceptions and learning outcomes of computer-assisted versus traditional instruction in physiology

This study compared student perceptions and learning outcomes of computer-assisted instruction against those of traditional didactic lectures. Components of Quantitative Circulatory Physiology (Biological Simulators) and Mechanical Properties of Active Muscle (Trinity Software) were used to teach regulation of tissue blood flow and muscle mechanics, respectively, in the course Medical Physiology. These topics were each taught, in part, by 1) standard didactic lectures, 2) computer-assisted lectures, and 3) computer laboratory assignment. Subjective evaluation was derived from a questionnaire assessing student opinions of the effectiveness of each method. Objective evaluation consisted of comparing scores on examination questions generated from each method. On a 1-10 scale, effectiveness ratings were higher (P < 0.0001) for the didactic lectures (7.7) compared with either computer-assisted lecture (3.8) or computer laboratory (4.2) methods. A follow-up discussion with representatives from the class indicated that students did not perceive computer instruction as being time effective. However, examination scores from computer laboratory questions (94.3%) were significantly higher compared with ones from either computer-assisted (89.9%; P < 0.025) or didactic (86.6%; P < 0.001) lectures. Thus computer laboratory instruction enhanced learning outcomes in medical physiology despite student perceptions to the contrary.

The effect of botulinum toxin on hand function after incomplete spinal cord injury at the level of C5/6: a case report

OBJECTIVE

To investigate the benefits of the focal use of botulinum toxin in spasticity in the forearm seen after incomplete spinal cord injury.

DESIGN

A single case study with standardized assessment before and at three-week intervals after injection.

INTERVENTION

EMG-guided selective injection of botulinum toxin.

SUBJECT

A 23-year-old man, 18 months post injury.

MEASURES

Rivermead Motor Assessment; grip strength; Jebsen hand tests; visual analogue scale; Ashworth spasticity scale.

RESULTS

Weakness was seen as expected with some functional losses, but the patient made gains in the areas of concern: shaking hands, typing, using the hand to drink. These gains were sustained at 12 weeks.

CONCLUSION

Selective use of botulinum toxin to weaken muscles can lead to functional benefit.

The maternity waiting home concept: the Nsawam, Ghana experience. The Accra PMM Team

PRELIMINARY STUDIES

Focus group discussions with community members in Nsawam District, Ghana, identified poor roads, scarce transport and exorbitant fees for emergency transport as barriers to reaching the district hospital for treatment of an obstetric complication.

INTERVENTIONS

To minimize delay in the event of a complication, a maternity waiting home (MWH) was established in Nsawam in 1994. One ward of an abandoned hospital was renovated and furnished for this purpose. The objective was to encourage women at high risk of obstetric complications to move to the MWH so they could be transferred to the hospital when labor began.

RESULTS

Of 25 women referred to the MWH by health personnel over 12 months, only one complied, for one night. Focus group discussions with community members and hospital staff later revealed that cost and hardship of staying away from home, absence of health personnel, distance from hospital, desolate surroundings and lack of perceived need were reasons for poor utilization.

COSTS

The intervention cost approximately US $10,500, shared approximately equally between the project and government. The main government contribution was the building.

CONCLUSIONS

It is important to consult potential users not only to identify problems, but also to identify appropriate solutions. Careful 'market research' should be done before launching interventions.

From abandoned warehouse to life-saving facility, Pakro, Ghana. The Accra PMM Team

PRELIMINARY STUDIES

Focus group discussions in Akwapim South District, Ghana, highlighted a lack of accessible health facilities as an important factor contributing to maternal deaths.

INTERVENTIONS

In 1991, a health center was established by rennovating an abandoned warehouse. The center was equipped with beds, a refrigerator, a safe water supply, drugs and supplies. With the posting of a community health nurse from the Ministry of Health (MOH), it began functioning as a maternal and child health/family planning clinic. A senior nurse-midwife was posted in 1992 and obstetric services were offered. Starting in 1994, community interventions focused on reducing the delay in seeking care.

RESULTS

An average of nine women with major obstetric complications were seen each 12-month period between 1992 and 1995. Many minor complications and non-obstetric ailments were also treated.

COSTS

The material costs of establishing the health center amounted to US $12,550: 47% came from the community, 43% came from non-governmental organizations (NGOs), 7% from PMM and 3% from MOH. The costs of staff salaries were paid by MOH.

CONCLUSIONS

It is possible to mobilize communities, government and NGOs to help provide emergency obstetric services. If emergency obstetric services are available, women will use them, even before the launching of community information and education campaigns.

Adrenocorticotropin-secreting carcinoid tumour identified and treated 12 years after presentation with Cushing's syndrome

A case of Cushing's syndrome due to an adrenocorticotropin (ACTH) secreting bronchial carcinoid tumour is described. Endocrine assessment suggested ectopic ACTH syndrome, but imaging revealed no tumour. Bilateral adrenalectomy was performed, and computed tomographic scans of chest and abdomen were performed annually. A small nodule became apparent in the right lung 12 years after the presentation, which postoperatively was confirmed as the bronchial carcinoid tumour responsible for the ectopic ACTH syndrome.

Immune deficiencies in chronic intestinal pseudo-obstruction

AIM

Chronic intestinal pseudo-obstruction has been associated with urinary disorders, myopathy, and ophthalmoplegia in adults and cholelithiasis in children. We observed a high percentage of total-parenteral-nutrition-dependent patients with pseudo-obstruction and recurrent infections requiring gammaglobulin infusions.

METHODS

All records for 23 children with chronic intestinal pseudo-obstruction (10 females and 13 males, mean age 9.8 y +/- 4.9 y, range 4-24 y) referred for a nutritional evaluation from 1992 to 1995 were reviewed. Chronic intestinal pseudo-obstruction was diagnosed by clinical, radiographic findings and antroduodenal manometry. Intestinal full-thickness biopsies were performed in seven children.

RESULTS

Hypogammaglobulinemia was diagnosed in 18 patients (78%): 16 patients had various immunoglobulin deficiencies and 2 had selective antibody deficiency. Intravenous gammaglobulin was administered in 14 patients. Other medical conditions affecting the children are summarized as follows: autonomic dysfunction in 10 patients (43%), recurrent hypoglycemia in 9 (39%), asthma in 9 (39%), cholecystitis in 7 (30%), low serum carnitine level in 6 (26%), urinary dysfunction in 6 (26%), pancreatitis in 5 (22%), behavioral problems in 5 (22%), myopathy in 2 (9%), idiopathic thrombocytopenia in 2 (8%), velopharyngeal insufficiency in 1 (4%), oculocutaneous albinism in 1 (4%), Pierre-Robin syndrome in 1 (4%), and protein C deficiency in 1 (4%). Munchausen syndrome was suspected in two patients.

CONCLUSIONS

Chronic intestinal pseudo-obstruction appears to be associated with immune deficiencies. It is unclear if the immune deficiencies, intestinal pseudo-obstruction, and the other medical conditions have a common underlying etiology. Repeated infections may be due to impaired immune function in children with chronic intestinal pseudo-obstruction. We recommend screening for immune deficiencies in children with chronic intestinal pseudo-obstruction.

The complete genome sequence of the gastric pathogen Helicobacter pylori

Helicobacter pylori, strain 26695, has a circular genome of 1,667,867 base pairs and 1,590 predicted coding sequences. Sequence analysis indicates that H. pylori has well-developed systems for motility, for scavenging iron, and for DNA restriction and modification. Many putative adhesins, lipoproteins and other outer membrane proteins were identified, underscoring the potential complexity of host-pathogen interaction. Based on the large number of sequence-related genes encoding outer membrane proteins and the presence of homopolymeric tracts and dinucleotide repeats in coding sequences, H. pylori, like several other mucosal pathogens, probably uses recombination and slipped-strand mispairing within repeats as mechanisms for antigenic variation and adaptive evolution. Consistent with its restricted niche, H. pylori has a few regulatory networks, and a limited metabolic repertoire and biosynthetic capacity. Its survival in acid conditions depends, in part, on its ability to establish a positive inside-membrane potential in low pH.

Trends in fatal occupational injuries and industrial restructuring in North Carolina in the 1980s

OBJECTIVES

This study examined the relationship between changes in employment in North Carolina in the 1980s and fatal occupational injury rates.

METHODS

Unintentional fatal occupational injuries (n = 1989) in North Carolina between 1978 and 1991 were identified via the medical examiner's system.

RESULTS

Overall fatal injury rates declined during the 1980s, but rates increased 9.6% per year among manufacturing industries that declined in employment size; rates fell among service sector and manufacturing industries that grew.

CONCLUSIONS

Increasing occupational fatal injury rates accompanied the decline in workforce in North Carolina's traditional, labor-intensive manufacturing industries during the 1980s, while service sector and expanding manufacturing industries have experienced declining fatal injury rates.

Magnetic source imaging evidence of sex differences in cerebral lateralization in schizophrenia

BACKGROUND

It has been postulated that schizophrenia represents a disorder of anomalous cerebral lateralization. This study is a replication of earlier preliminary findings using a multichannel neuromagnetometer, suggesting altered lateralization in schizophrenia in male subjects, with an extension of the findings to female subjects.

METHODS

We used magnetoencephalography-based magnetic source imaging to estimate the intracranial location of the 100-millisecond latency auditory-evoked field component (M100) in both left and right hemispheres of 20 patients with paranoid schizophrenia and 20 controls without schizophrenia. Neuroanatomical data were obtained by means of magnetic resonance imaging, from which we segmented and computed volumes of both total brain and left and right superior temporal gyri.

RESULTS

Locations of M100 source were compatible with neuronal generators located in the transverse gyri of Heschl on the superior temporal gyri in both study groups; M100 sources were asymmetric in all the control subjects. The male patient subgroup exhibited significantly less asymmetry than the control group, while the female patient subgroup actually showed significantly more asymmetry. The male patient subgroup generally had smaller superior temporal gyri than the control group. No evidence of total brain volume differences was observed.

CONCLUSIONS

Our findings support previous magnetoencephalography-based studies suggesting anomalous cerebral lateralization in schizophrenia. Further, in extending our studies to female patients, our data suggest that the nature of this anomaly is sex specific, a finding that, to our knowledge, has not previously been reported.

Fatal agricultural injuries in North Carolina by race and occupation, 1977-1991

Medical examiner reports and death certificates were reviewed for all fatal agricultural injuries (n = 228) that occurred on-the-job in North Carolina between 1977 and 1991. Data were collected on the decedents' age, gender, race, data and time of injury, means of injury, and occupation. Annual workforce estimates were derived from the 1980 and 1990 US Census of the Population. Overall, 54% of the fatal injuries were due to tractors. Farmers who suffered fatal injuries tended to be older (median age = 56 years) and Caucasian (87%), while farm workers who died on the job were younger (median age = 35 years) and more often African-American (60%). The crude mortality rate for farmers was 38 per 100,000 worker-years; the crude rate for farm laborers was 16 per 100,000 worker-years. Age-adjusted fatal injury rates were 2.5 times higher among African-American farmers than among Caucasian farmers; furthermore, between 1977 and 1991 the rate of fatal injury among African-American farmers increased an estimated 14.7% per year. African-American farmers in North Carolina have experienced rising rates of fatal injuries at a time when employment in the industry is declining due to consolidation of farm ownership and foreclosures of African-American owned farms. In order to address the growing racial disparity in farm fatalities, efforts need to be made to improve the conditions under which African-American farmers are working.

A simple program to create exact person-time data in cohort analyses

BACKGROUND

Before disease rates can be calculated a tabulation of the length of follow-up for each person in the cohort has to be made. In complicated analyses such tabulations are often stratified by many characteristics, some which show no change with time, such as gender or year of birth, and some which do change with time, such as age or cumulative exposure. Available computer programs often restrict the way these tables can be made, particularly when handling time-dependent variables.

METHODS

This paper presents a simple computer program which calculates the length of follow-up for each person in a study.

RESULTS

Person-time data can be tabulated by a large number of variables using this method. This program is extremely flexible in the way that time-dependent variables can be created, can categorize observations by any unit of person-time, and will run on a range of platforms including a personal computer.

CONCLUSIONS

This method should simplify the task of creating person-time data for analyses of disease rates in epidemiological studies.

Systemic embolisation

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A reevaluation of cancer incidence near the Three Mile Island nuclear plant: the collision of evidence and assumptions

Previous studies concluded that there was no evidence that the 1979 nuclear accident at Three Mile Island (TMI) affected cancer incidence in the surrounding area; however, there were logical and methodological problems in earlier reports that led us to reconsider data previously collected. A 10-mile area around TMI was divided into 69 study tracts, which were assigned radiation dose estimates based on radiation reading and models of atmospheric dispersion. Incident cancers from 1975 to 1985 were ascertained from hospital records and assigned to study tracts. Associations between accident doses and incidence rates of leukemia, lung cancer, and all cancer were assessed using relative dose estimates calculated by the earlier investigators. Adjustments were made for age, sex, socioeconomic characteristics, and preaccident variation in incidence. Considering a 2-year latency, the estimated percent increase per dose unit +/- standard error was 0.020 +/- 0.012 for all cancer, 0.082 +/- 0.032 for lung cancer, and 0.116 +/- 0.067 for leukemia. Adjustment for socioeconomic variables increased the estimates to 0.034 +/- 0.013, 0.103 +/- 0.035, and 0.139 +/- 0.073 for all cancer, lung cancer, and leukemia, respectively. Associations were generally larger considering a 5-year latency, but were based on smaller numbers of cases. Results support the hypothesis that radiation doses are related to increased cancer incidence around TMI. The analysis avoids medical detection bias, but suffers from inaccurate dose classification; therefore, results may underestimate the magnitude of the association between radiation and cancer incidence. These associations would not be expected, based on previous estimates of near-background levels of radiation exposure following the accident.

Cytosolic Ca2+ and adenylyl cyclase responses in phenotypically distinct pulmonary endothelial cells

Pulmonary microvascular endothelium forms a tighter barrier than does pulmonary artery endothelium; the mechanism of this important phenotypic difference is uncertain. We examined two regulators of endothelial permeability, cytosolic Ca2+ concentration ([Ca2+]i) and adenosine 3',5'-cyclic monophosphate (cAMP), in microvascular (PMVEC) and pulmonary conduit artery (PAEC) endothelium. Both resting and stimulated [Ca2+]i were lower in PMVEC compared with PAEC (resting [Ca2+]i, 94 +/- 7 vs. 123 +/- 8 nM; ATP-stimulated peak, 1.04 +/- 0.14 vs. 1.98 +/- 0.13 microM). Sustained Ca2+ transients in response to either ATP or thapsigargin were reduced in PMVEC compared with PAEC (ATP, 199 +/- 22 vs. 411 +/- 43 nM; thapsigargin, 195 +/- 13 vs. 527 +/- 65 nM), suggesting reduced Ca2+ influx in PMVEC. Reduced Ca2+ influx in PMVEC was confirmed by Mn2+ quenching and patch-clamp experiments. mRNA for Ca(2+)-inhibitable and protein kinase C-stimulated adenylyl cyclases was detected in both cell types. Whereas ATP caused a [Ca2+]i-mediated decrease in cAMP in PAEC, ATP caused a protein kinase C-mediated increase in cAMP in PMVEC. We conclude that PMVEC express a unique phenotype that favors enhanced barrier function through attenuated Ca2+ influx and preservation of cAMP content.

Radial forearm flap donor-site complications and morbidity: a prospective study

One-hundred patients undergoing radial forearm flap reconstruction in the head and neck over a 2-year period were followed prospectively to assess complications and morbidity associated with the radial flap donor site. Eighty-six patients were available follow-up at 3 months and 74 at 1 year (49 fasciocutaneous, 25 composite). Partial loss of the donor-site skin graft occurred in 14 patients (16 percent), with exposure of tendons in 11 patients (13 percent). Delay in healing of the split-thickness skin graft at the donor site occurred in 19 patients (22 percent). Fracture of the radius occurred in 6 of 35 patients with composite flaps (17 percent). Superficial radial nerve sensation was reduced in 24 patients (32 percent) at 1 year. Ten patients (14 percent) reported cold intolerance, and 21 patients (28 percent) complained of poor aesthetic result. Function of the donor arm was restricted in 8 patients (16 percent) in the fasciocutaneous group, in 7 patients (36 percent) in the composite group without fracture, and in all patients who had a fracture of the radius following harvesting of composite flaps. Detailed measurements of forearm circumference, grip strength, pinch strength, and wrist movements showed greater reduction in these parameters in patients reporting restricted function compared with those reporting normal function. It is concluded that there is a low incidence of long-term morbidity associated with fasciocutaneous flaps and a higher incidence with composite flaps. Fracture of the radius results in reduced function in all cases.

Using situational physiology in a didactic lecture setting

This project used the approach of "human situations" to teach about the cardiovascular system within an undergraduate physiology course (PGY 412). About two-thirds of the students had previously taken a college-level physiology course (sophisticated), whereas one-third had not (naive). Nine didactic lectures were organized around the common human situations of orthostasis, blood donation, and exercise. For acceptance evaluation, the students were given a questionnaire consisting of six expectation statements (e.g., compared with other life science courses, I expect that I will better understand the material) and asked to rate the degree to which they agreed with each statement on a scale of 1 to 5. On completion of the lectures, the students were given a questionnaire asking them to compare experiences with expectations. Experiences were significantly less than expectations for naive (P < 0.05) but not for sophisticated students. On a scale of 1 to 5, sophisticated students preferred the situations approach more than did naive students (3.1 vs 2.4; P < 0.066). For performance evaluation, the students were given a set of questions used by the author in a previous PGY 412 course presented by traditional didactic lectures. There were no significant differences between present and previous scores (77 vs. 79%; P > 0.16). Furthermore, there were no significant differences between naive and sophisticated students in cardiovascular examination scores (P > 0.608) or in total course scores (P > 0.523). These results indicate that didactic lectures based on situational physiology will yield a performance outcome equivalent to traditional lectures. However, naive students may have difficulty with the procedure and require extra attention.

Crystal structures of a single coiled-coil peptide in two oligomeric states reveal the basis for structural polymorphism

Each protein sequence generally adopts a single native fold, but the sequence features that confer structural uniqueness are not well understood. To define the basis for structural heterogeneity, we determined the high resolution X-ray crystal structures of a single GCN4 leucine-zipper mutant (Asn 16 to aminobutyric acid) in both dimeric and trimeric coiled-coil conformations. The mutant sequence is accommodated in two distinct structures by forming similarly-shaped packing surfaces with different sets of atoms. The trimer structure, in comparison to a previously-characterized trimeric mutant with substitutions in eight core residues, shows that the twist of individual helices and the helix-helix crossing angles can vary significantly to produce the most favoured packing arrangement.

Establishing a community network for recruitment of African Americans into a clinical trial. The African-American antiplatelet stroke Prevention Study (AAASPS) experience

A major aspect of a clinical trial is the ability to successfully recruit patients. There is a paucity of information concerning the nuances of recruiting study patients, especially those from minority communities. As minorities generally have been underrepresented in the health-care system, they may be less likely to participate in clinical trials or other studies. Thus, a strategy is needed to overcome this potential shortfall. One of our solutions has been the development of a community network to help disseminate information about our program. We believe that a key aspect has been the involvement of community members during pre-trial planning, community awareness programs, and our Community Advisory Panel. We also believe that it may be a major error to bring a health-care initiative unannounced into a targeted community without extensive pre-program planning in cooperation with that community. As our community awareness scheme suggests (Figure), there are many possible avenues to heighten awareness about a health-care program. While the church remains an important institution for religious and cultural activities in the African-American community, we have found that the news, television, and radio media also can be a powerful source for spreading awareness. Thus, we recommend creating awareness about an initiative through a "grassroots" approach of church and community organizations, along with a global approach through news, television, and radio media. As part of the awareness promotion campaign, it must be emphasized that the study is safe and provides benefits to enrollees. The success of health programs is largely dependent on community acceptance, which must be established in the pre-program planning stages of the initiative. This concept of obtaining community approval and acceptance prior to program initiation is not a new one, nor does it exclusively apply to the African-American community. Community leaders and members need to have a vested interest in such a program and a sense of empowerment. Through this type of communication, patient enrollment and community satisfaction can be substantial. Such success can serve as a springboard for other targeted health-care studies or programs in high-risk communities.

Reproducibility of MEG auditory evoked field source localizations in normal human subjects using a seven-channel gradiometer

Magnetoencephalographic (MEG) auditory evoked fields (EF) were recorded from 12 normal adult subjects over both hemispheres on two separate occasions at least one week apart using a seven-channel second-order gradiometer. Stimuli were computer-generated at 25-msec duration, 1 kHz tone pips. Responses to 100 stimuli were averaged, and source estimates with confidence intervals were computed, for the 100-msec latency auditory EF component, termed M100. Root-mean-squared (rms) differences in x, y, and z locations were approximately 0.7 cm on the two occasions; strength and orientation differences were 18 nA-m and 11 degrees, respectively. This spatial accuracy using a seven-channel instrument, compares favorably with other currently available technologies for localization of brain function.

Experience of coding ambulatory visits to outpatient clinics

Clinical data for all current outpatients at a large tertiary hospital has been collected for analysis. Patient diagnoses for selected "key" clinics have been coded to ICD-9-CM standards. Methods to reduce the volume of coding required for such data collection are discussed, and include short-lists of codes, default assignment of diagnoses codes according to the nature of visit, and producing a "discharge" summary for outpatients, similar to that routinely produced for inpatients.

Necrotizing cerebritis in an allogeneic bone marrow transplant recipient due to Cladophialophora bantiana

We describe a necrotizing cerebritis in an allogeneic bone marrow transplant recipient caused by the neurotropic, dematiaceous fungus Cladophialophora bantiana. The patient presented 7 months after bone marrow transplantation with fever and sudden onset of left-sided weakness, followed shortly by cranial nerve III and VI palsies. The patient had a lesion (3.0 by 2.0 by 2.0 cm) of the right midbrain with extension to the pons, the left brain stem, and the right superior and the middle cerebellar peduncles. The diagnosis was made by microscopic examination and culture of a brain biopsy.

Evidence of deteriorating semen quality in the United Kingdom: birth cohort study in 577 men in Scotland over 11 years

OBJECTIVE

To determine whether the quality of semen has changed in a group of over 500 Scottish men born between 1951 and 1973.

DESIGN

Retrospective review of data on semen quality collected in a single laboratory over 11 years and according to World Health Organisation guidelines.

SETTING

Programme of gamete biology research funded by Medical Research Council.

SUBJECTS

577 volunteer semen donors. Of these, 171 were born before 1959, 120 were born in 1960-4, 171 in 1965-9, and 115 in 1970-4.

MAIN OUTCOME MEASURES

Conventional criteria of semen quality including semen volume (ml), sperm concentration (10(6)/ml), overall motility (% motile), total number of sperm in the ejaculate (10(6)), and total number of motile sperm in the ejaculate (10(6)).

RESULTS

When the four birth cohort groups were compared a later year of birth was associated with a lower sperm concentration, a lower total number of sperm in the ejaculate, and a lower number of motile sperm in the ejaculate. The median sperm concentration fell from 98x10(6)/ml among donors born before 1959 to 78x10(6)/ml among donors born after 1970 (P=0.002). The total number of sperm in the ejaculate fell from 301x10(6) to 214x10(6) (P=0.0005), and the total number of motile sperm in the ejaculate fell from 169.7x10(6) to 129.0x10(6) (P=0.0065).

CONCLUSION

This study provides direct evidence that semen quality is deteriorating, with a later year of birth being significantly associated with a reduced number of sperm in adult life.

MEG based brain laterality: sex differences in normal adults

Magnetoencephalographic (MEG) auditory evoked fields produced by short tone pips were recorded from 34 normal adults (17 males, 17 females) and the 100 msec latency component (M100) localized in left and right hemispheres. Absolute M100 location in the antero-posterior dimension was calculated for each subject. M100 sources were significantly further anterior in the right hemisphere of males. Magnetic resonance (MR) based anatomy of the superior temporal gyri (STG) in a subset of 17 subjects showed that in the left STG of both males and females M100 sources were located approximately midway on the STG. In the right hemisphere of males, however, M100 sources were significantly further anterior on the STG than was the case for females. The findings are compatible with a sex based difference in right STG functional anatomy, with evidence of greater hemispheric lateralization in males compared to females based upon a predominantly right hemisphere contribution.

Reduction in accumulation of plaque, stain, and calculus in dogs by dietary means

We conducted 215 evaluations for plaque, stain, and calculus in 120 dogs at two research sites. Dogs were balanced in groups of five according to baseline plaque index scores; groups were randomly assigned to treatment or control dietary regimens. Dental cleanings were done on Day 0. Dogs in the treatment group were fed a food formulated to reduce accumulation of plaque, stain, and calculus. Control group dogs were fed a commercially available dry dog food. No other foods, treats, or snacks were given to either group. We graded 22 teeth for plaque accumulation on Day 7 and for stain and calculus accumulation on Day 21. Six trials were conducted and the results reported as a combined mean for all treatment and control groups. Dogs fed the treatment food had significantly less plaque, stain, and calculus accumulation (p = 0.001) than dogs fed the control food. Plaque, stain, and calculus accumulation can be reduced by dietary means.