Complications associated with limb salvage for extremity sarcomas and their management

A retrospective clinical review of 100 consecutive patients with extremity sarcomas managed by limb salvage operations was performed to evaluate local tumor control and morbidity. The mean follow-up period was 45.1 months. Overall survival was 86%. There were local recurrences in 3% of patients, and 26 complications in 22 patients. Wound necrosis was the most frequent complication. Failure of allogeneic bone graft operations occurred in 25 patients. Most of the complications were salvageable without loss of limb. Limb salvage is an acceptable surgical treatment of extremity sarcomas based on adequate local control and minimal morbidity.     

Policy incongruence and public health professionals' dissonance: the case of immigrants and welfare policy

The steady increase in immigrants to the United States has fueled a critical analysis of the process of allocation of health and social benefits to these newcomers. The myriad of interests and values surrounding this issue precipitated the formulation and adoption of the Personal Responsibility and Work Opportunity (Welfare Reform) Act of 1996. This dramatic welfare reform impacts federal, state, and local agencies that are required to determine the eligibility of benefits and manage the attendant consequences to the public as well as members of this vulnerable group. Especially challenging are the decisions confronting public health professionals who struggle to reconcile the resulting policy, programmatic mandates, and compliance imperatives with prevailing public health principles and practice norms. This paper proposes a framework for understanding the incongruence between the provisions of the law as it pertains to legal and illegal immigrants and public health values. The impact of policy incongruence and professionals' dissonance on public health practice norms is explored with an explicit focus on public health outcomes and legal implications. The examination of tuberculosis as a health example reveals the policy conflicts and public health dilemmas. Finally, the paper elicits a range of options available to public professionals for responding to these legal mandates.     

The effect of hypothermic cardiopulmonary bypass and total circulatory arrest on cerebral metabolism in neonates, infants, and children

Cardiopulmonary bypass management in neonates, infants, and children often requires the use of deep hypothermia at 18 degrees C with occasional periods of circulatory arrest and represents marked physiologic extremes of temperature and perfusion. The safety of these techniques is largely dependent on the reduction of metabolism, particularly cerebral metabolism. We studied the effect of hypothermia on cerebral metabolism during cardiac surgery and quantified the changes. Cerebral metabolism was measured before, during, and after hypothermic cardiopulmonary bypass in 46 pediatric patients, aged 1 day to 14 years. Patients were grouped on the basis of the different bypass techniques commonly used in children: group A--moderate hypothermic bypass at 28 degrees C; group B--deep hypothermic bypass at 18 degrees to 20 degrees C with maintenance of continuous flow; and group C--deep hypothermic circulatory arrest at 18 degrees C. Cerebral metabolism significantly decreased under hypothermic conditions in all groups compared with control levels at normothermia, the data demonstrating an exponential relationship between temperature and cerebral metabolism and an average temperature coefficient of 3.65. There was no significant difference in the rate of metabolism reduction (temperature coefficient) in patients cooled to 28 degrees and 18 degrees C. From these data we were able to derive an equation that numerically expresses a hypothermic metabolic index, which quantitates duration of brain protection provided by reduction of cerebral metabolism owing to hypothermic bypass over any temperature range. Based on this index, patients cooled to 28 degrees C have a predicted ischemic tolerance of 11 to 19 minutes. The predicted duration that the brain can tolerate ischemia ("safe" period of deep hypothermic circulatory arrest) in patients cooled to 18 degrees C, based on our metabolic index, is 39 to 65 minutes, similar to the safe period of deep hypothermic circulatory arrest known to be tolerated clinically. In groups A and B (no circulatory arrest), cerebral metabolism returned to control in the rewarming phase of bypass and after bypass. In group C (circulatory arrest), cerebral metabolism and oxygen extraction remained significantly reduced during rewarming and after bypass, suggesting disordered cerebral metabolism and oxygen utilization after deep hypothermic circulatory arrest. The results of this study suggest that cerebral metabolism is exponentially related to temperature during hypothermic bypass with a temperature coefficient of 3.65 in neonates infants and children. Deep hypothermic circulatory arrest changes cerebral metabolism and blood flow after the arrest period despite adequate hypothermic suppression of metabolism.     

"The facts concerning the recent carnival of smoking in Connecticut" and elsewhere

The behavior of health care practitioners toward their patients can greatly affect the patients' motivation for change. Mark Twain's story, "The Facts Concerning the Recent Carnival of Crime in Connecticut," is used to illustrate how traditional strategies for motivating patients to change can have the paradoxic effect of inhibiting change and growth. We use a theory of human motivation, referred to as self-determination theory, to explain this effect and suggest alternative strategies for facilitating patient motivation. Empirical tests of the theory have shown that people will accept more responsibility for behavior change when motivated internally rather than externally. In the doctor-patient relationship, this internal motivation for change can be facilitated when doctors allow choice, provide relevant information, and acknowledge the patient's perspective. We propose a simple, three-question model, consistent with self-determination theory, for physicians to use with patients who smoke and are not yet ready to try quitting.     

Medical resident education. A cross-sectional study of the influence of the ambulatory preceptor as a role model

A teaching practice of a residency program in primary care internal medicine was used for a cross-sectional study of the record-keeping habits of ambulatory preceptors and the residents they supervise. A retrospective review of 12 charts per physician over a six-month period was used to compare the charting behavior of three practice groups. Each group was comprised of an attending preceptor and a resident in each of the first, second, and third years of residency. Compared with the other two ambulatory preceptors, one ambulatory preceptor had significantly fewer charts with problem lists, medication lists, and health maintenance records as well as a lower ratio of psychosocial problems to total problems noted on his problem lists. The medical records of the residents supervised by this ambulatory preceptor were also significantly more deficient in each of these areas than the medical records of the other two resident groups. The fact that poor medical record keeping by an ambulatory preceptor was similarly deficient for the residents he supervised across each major area studied suggests that the ambulatory preceptor's actual practice behavior may exert a broad influence on the behavior of his residents. Future educational efforts in primary care internal medicine should be partially directed toward the ambulatory preceptors who serve as potent role models.     

Site-directed mutagenesis and the role of the oxyanion hole in subtilisin

Oligonucleotide-directed mutagenesis was used to investigate the nature of transition state stabilization in the catalytic mechanism of the serine protease, subtilisin BPN'. The gene for this extracellular enzyme from Bacillus amyloliquefaciens has been cloned and expressed in Bacillus subtilis. In the transition state complex, the carbonyl group of the peptide bond to be hydrolyzed is believed to adopt a tetrahedral configuration rather than the ground-state planar configuration. Crystallographic studies suggest that stabilization of this activated complex is accomplished in part through the donation of a hydrogen bond from the amide side group of Asn-155 to the carbonyl oxygen of the peptide substrate. To specifically test this hypothesis, leucine was introduced at position 155. Leucine is isosteric with asparagine but is incapable of donating a hydrogen bond to the tetrahedral intermediate. The Leu-155 variant was found to have an unaltered Km but a greatly reduced catalytic rate constant, kcat, (factor of 200-300 smaller) when assayed with a peptide substrate. These kinetic results are consistent with the Asn-155 mediating stabilization of the activated complex and lend further experimental support for the transition-state stabilization hypothesis of enzyme catalysis.