Metabolism of rabbit angiostatin glycoforms I and II in rabbits: angiostatin-I leaves the intravascular space faster and appears to have greater anti-angiogenic activity than angiostatin-II

Plasminogen (PLG) exists in the circulation as two glycoforms, I and II. Angiostatin (AST) is a polypeptide that has been cleaved from the kringle region of PLG and has strong anti-angiogenic properties. AST-I and AST-II, which consisted only of kringles 1 through 3, were prepared by the action of urokinase on purified rabbit PLG-I and PLG-II, respectively, in the presence of N-acetyl cysteine, followed by affinity chromatography on lysine-Sepharose. Purified AST-I and AST-II were tested for functional activity with a chick chorioallantoic membrane (CAM) model; when similar amounts were applied to a 6-day CAM, AST-I was substantially more effective than AST-II in decreasing vascular supply to the CAM over a 72-hour period; this activity correlated with a loss of capillaries, probably through apoptosis of endothelial cells. Radiolabeled AST-I and AST-II (iodine 125 and iodine 131) were co-injected intravenously into healthy rabbits to determine their clearances from plasma measured over 3 days. Over a dose range of 0.08 to 2.7 microg/kg, the fractional catabolic rate within the intravascular space (j(3)) indicated that AST-I was cleared 3-fold to 4-fold more rapidly than AST-II (P < .001). The catabolic half-life of AST-I (2.01 +/- 0.19 days) was significantly less than that of AST-II (2.62 +/- 0.20 days). The faster clearance of AST-I from the intravascular space was matched by its more rapid passage than AST-II to the extravascular space of various organs over 60 minutes in vivo. This property of AST-I as compared with AST-II may partially explain its greater anti-angiogenic potential. From the plasma concentrations of PLG-I and PLG-II and their relative behaviors toward rabbit VX-2 lung tumors in vivo, we predict that substantially greater quantities of AST-II than AST-I may be released into the extravascular space of tumors.

What did we learn about national organizational collaboration at the advisory committee level?

This article provides an overview of the typical roles and tasks of advisory groups in general, followed by a discussion of the roles and tasks the Interdisciplinary Generalist Curriculum (IGC) Project Advisory Committee was asked to assume and how these were fulfilled. It analyzes the lessons learned about advisory committees as a result of the IGC Project experience. Key elements of success in fulfilling advisory committee obligations include well-defined expectations, periodic evaluations, and clear communication between project leadership and the members of the advisory committee. In the spirit of lessons learned from the IGC Project, this critique identifies several philosophical and logistic issues that might be considered in the design and implementation of future projects, such as the need to choose committed, high-energy advisory committee members who are willing to perform many complex, time-consuming tasks.

Gastrointestinal Stromal Tumors: Analysis of Clinical and Pathologic Factors

Gastrointestinal mesenchymal tumors have been classified as benign (leiomyoma) or malignant (leiomyosarcomas). More recently, these tumors have been termed gastrointestinal stromal tumors (GISTs). GISTs have a highly variable clinical course. This review analyzes the clinical presentation, pathologic examination, and long-term follow-up of patients with GIST. A retrospective analysis of the clinical course of patients with GIST at a single institution from 1986 to 1998 was performed. Nineteen patients with GIST (12 gastric, two duodenal, three jejunal, and two rectal) were treated. The most common clinical presentation was gastrointestinal bleed. CT scans, contrast studies, and endoscopy were used to identify a tumor mass. Diagnosis of GIST was made in only two patients preoperatively. Tumor size ranged from 0.8 to 23 cm. Histology of the tumors was variable. All patients underwent surgical resection with curative intent. Follow-up ranged from 2 to 55 months. There were two perioperative deaths. Local recurrence occurred in one patient. GISTs are uncommon. Preoperative diagnosis can be difficult, and often the diagnosis is made at the time of surgery. With complete resection of the tumor the clinical course is favorable with very few local recurrences. Therefore complete resection of the tumor is recommended.

Metastatic soft tissue squamous cell carcinoma

Metastatic squamous cell carcinoma of the soft tissue is extremely rare. We report two patients with soft tissue metastasis from squamous cell carcinoma of the cervix in one and scalp in another. Case 1: A 63-year-old black woman with a history of cervical cancer presented with a painful mass over the right scapula. An incisional biopsy revealed squamous cell carcinoma. She underwent radiation treatment followed by wide local excision with en bloc resection and a myocutaneous flap closure. Case 2: A 46-year-old white man with a history of squamous cell carcinoma of the scalp and two kidney transplantations requiring long-term immunosuppression presented with a 2-month history of a left proximal arm mass. Magnetic resonance imaging revealed that the mass was within the triceps muscle and fixed to the humerus. Biopsy revealed squamous cell carcinoma. He underwent a shoulder disarticulation for tumor invasion into the adjacent humerus and neurovascular bundles. The patients remain disease-free at 12 and 8 months, respectively. To our knowledge there are no reports of soft tissue squamous cell carcinoma metastatic from the cervix and only rare cases from the lung, head, and neck. The optimal mode of treatment and prognosis is undefined in these patients because of its rare incidence. Surgery and radiation with curative intent were used.

Application of rat hepatocyte culture to predict in vivo metabolic auto-induction: studies with DFP, a cyclooxygenase-2 inhibitor

The drug candidate DFP [5,5-dimethyl-3-(2-isopropoxy)-4-(4-methanesulfonylphenyl)-2(5H)-furanone] is a selective cyclooxygenase-2 inhibitor under evaluation for analgesic and anti-inflammatory therapy. The in vitro metabolic pathways (rat microsomes) involve hydroxylation of the isopropyl side chain at either of two positions, the methyl or the methine, thus producing a hydroxylated metabolite (DFHP) or a dealkylated metabolite (DFH). DFH formation was the major pathway. Using hepatic microsomes from rats treated with agents that induce specific CYP isozymes, it was shown that the dexamethasone-inducible rat CYP3A isozyme(s) play a major role in DFH formation. The roles of CYP3A1 and -3A2 were confirmed with genetically engineered rat CYP enzymes. The potential for induction of rat CYP3A by DFP was evaluated by incubating DFP in rat hepatocyte cultures and measuring the CYP3A levels. Both CYP3A immunoreactive protein and enzyme activity were induced in a dose-dependent manner. The induction was confirmed in vivo by dosing rats with DFP at 100 mg/kg for 4 days. Microsomes prepared from the excised livers showed that DFP gave approximately 55% of the induction observed with dexamethasone, as determined by Western blot. In vitro metabolic auto-induction of DFP was assessed by measuring the metabolism of DFP in hepatocytes treated with DFP. DFH formation was significantly enhanced in the DFP-treated cells. In vivo, treating rats with DFP at doses of 10 to 100 mg/(kg.day) for 13 weeks indicated that DFP induced its own metabolism. The C(max) and plasma drug area under the curve values during the thirteenth week were significantly lower than that on the first day, and the effect was dose-dependent.

Gastrointestinal stromal tumors: analysis of clinical and pathologic factors

Gastrointestinal mesenchymal tumors have been classified as benign (leiomyoma) or malignant (leiomyosarcomas). More recently, these tumors have been termed gastrointestinal stromal tumors (GISTs). GISTs have a highly variable clinical course. This review analyzes the clinical presentation, pathologic examination, and long-term follow-up of patients with GIST. A retrospective analysis of the clinical course of patients with GIST at a single institution from 1986 to 1998 was performed. Nineteen patients with GIST (12 gastric, two duodenal, three jejunal, and two rectal) were treated. The most common clinical presentation was gastrointestinal bleed. CT scans, contrast studies, and endoscopy were used to identify a tumor mass. Diagnosis of GIST was made in only two patients preoperatively. Tumor size ranged from 0.8 to 23 cm. Histology of the tumors was variable. All patients underwent surgical resection with curative intent. Follow-up ranged from 2 to 55 months. There were two perioperative deaths. Local recurrence occurred in one patient. GISTs are uncommon. Preoperative diagnosis can be difficult, and often the diagnosis is made at the time of surgery. With complete resection of the tumor the clinical course is favorable with very few local recurrences. Therefore complete resection of the tumor is recommended.

Metastatic Soft Tissue Squamous Cell Carcinoma

Metastatic squamous cell carcinoma of the soft tissue is extremely rare. We report two patients with soft tissue metastasis from squamous cell carcinoma of the cervix in one and scalp in another. Case 1: A 63-year-old black woman with a history of cervical cancer presented with a painful mass over the right scapula. An incisional biopsy revealed squamous cell carcinoma. She underwent radiation treatment followed by wide local excision with en bloc resection and a myocutaneous flap closure. Case 2: A 46-year-old white man with a history of squamous cell carcinoma of the scalp and two kidney transplantations requiring long-term immunosuppression presented with a 2-month history of a left proximal arm mass. Magnetic resonance imaging revealed that the mass was within the triceps muscle and fixed to the humerus. Biopsy revealed squamous cell carcinoma. He underwent a shoulder disarticulation for tumor invasion into the adjacent humerus and neurovascular bundles. The patients remain disease-free at 12 and 8 months, respectively. To our knowledge there are no reports of soft tissue squamous cell carcinoma metastatic from the cervix and only rare cases from the lung, head, and neck. The optimal mode of treatment and prognosis is undefined in these patients because of its rare incidence. Surgery and radiation with curative intent were used.

Parental health beliefs and compliance with prophylactic penicillin administration in children with sickle cell disease

PURPOSE

Prophylactic penicillin is effective in preventing severe invasive pneumococcal infection in children with sickle cell disease. In some families, compliance has been problematic. The aims of this study were to monitor compliance and to assess the efficacy of the Health Belief Model (HBM) in predicting compliance.

METHODS

Fifty mothers of children with sickle cell disease, ages 6 to 60 months, participated in the study. On enrollment, mothers completed surveys assessing their health beliefs regarding sickle cell disease and infections. Compliance was assessed through self-reporting by the mothers and through review of local pharmacy records of penicillin refills.

RESULTS

Sixty percent of the mothers reported that they were highly compliant with obtaining the prescribed 14-day refills. Pharmacy records indicated that only 12% actually adhered to this schedule. The self-reports were significantly related to compliance ratings; mothers who admitted less than optimal compliance averaged 42 days between refills, compared with 19 days for mothers who reported good compliance. Varying perceptions identified through the HBM accounted for approximately 30% of the variance in compliance rates. The perceived burdens of picking up the refills and remembering to administer the medication were the most significant factors.

CONCLUSIONS

Educational efforts alone are not sufficient to ensure compliance with penicillin prophylaxis. Routinely monitoring compliance through pharmacy records, reviewing parental beliefs about sickle cell disease and infections, and exploring barriers to treatment will promote dialogue about the importance of strict compliance with this relatively simple yet life-saving prophylaxis.

Fatigue-related changes in electomyogram activity of the cat gastrocnemius during frequency-modulated efferent stimulation

Changes in the compound muscle action potentials of cat gastrocnemius muscle were studied during low- and high-frequency fatigue. Fatiguing session consisted of 25-28 repetitions of the standard single fatigue tests (1.5min interval between the tests) that included the part of continuous frequency-modulated stimulation preceded and followed by single stimuli evoking twitch contractions in the muscle. The rate of the continuous part was changed in accordance with symmetrical double-trapezoidal signal, including three successive phases of constant rate at 10, 40 and 10s(-1); between these phases of 4s duration the rate changed linearly within a 2s interval. During fatigue relative changes in compound muscle action potential waves were usually smaller than changes in tension. Within the same fatigue procedure applied to a fresh muscle, the drop in tension was as much as 35% for high-rate stimulation and 59-71% for low-rate stimulation, whereas the decrease of the peak-to-peak compound muscle action potential waves amplitudes did not exceed 10-20%. Compound muscle action potential waves underwent the most pronounced depression during high-rate stimulation, the decrease proceeding during the following phase of low-rate stimulation. The tension changes during long-lasting activation were different for low- and high-frequency fatigue, with more pronounced depression during low-rate stimulation. As a rule, compound muscle action potential waves changes followed opposite patterns. Compound muscle action potential waves progressively split up, which was probably associated with a continuous slowing of the action potentials in the most fatigable motor units and the subsequent disappearance of the reactions at least in part of the motor units. Hysteresis effects in muscle contraction seem to be able, at least in part, to compensate for some of the depressive effects appearing during conduction of action potentials in muscle fibres. Changes in the compound muscle action potentials were studied during development of the muscle fatigue. These changes showed pronounced dependency on stimulation rate allowing differentiating effects of low- and high-frequency stimulation of the efferents supplying muscle under study. At the same time the fatigue-related changes in the action potentials were noticeably smaller than changes in tension, thus supporting existing concepts in the field arguing that fatigue effects are mainly connected with corresponding activity-dependent changes in muscle contraction machinery.

How to select covariates to include in the analysis of a clinical trial

The comparisons of treatments in randomized clinical trials may use the analysis of covariance to adjust for patient characteristics. We present theoretical results that describe when such an adjustment would be expected to be beneficial. A distinction is made between covariates that are balanced in the design and those that are assigned by the randomization process. The results support the commonly held view that features balanced in the design of the trial (e.g., by stratification) and those that are strongly predictive of the outcome, and thus considered clinically prognostic, should normally be included in the analysis. For other covariates that are not balanced in the design, the potential benefits of including them in the analysis will depend on the number of patients in the trial. However, there is frequently a set of variables whose relevance is unknown and for which data-dependent methods of selection, based on the data for the current trial, have been proposed. A review of the literature has shown that these methods can produce misleading inferences. The decision as to which covariates to include in the analysis should be specified in the protocol on the basis of data from previous trials on similar patient populations. The methods are illustrated with data from a trial comparing two therapies for treating scalp psoriasis where the clinical importance of patients' age and sex as prognostic factors for efficacy is unknown. We show for what size of future trials it would be beneficial to adjust for these covariates and for what size trials it would not. In all cases, prespecification of variables to be included in the analysis is essential in order to avoid bias.

Identification of a new HLA-B*39 allele: HLA-B*3924

We have identified a new HLA-B*39 allele through polymerase chain reaction (PCR) using sequence-specific primers (SSP) and sequence-based typing of exons 2 and 3. This novel allele was identified in three HLA-identical siblings of Turkish origin. This allele only differs from HLA-B*3903 at a unique single nucleotide substitution (T for C) at position 365 in exon 3 which results in an amino acid change in codon 98 of methionine (ATG) to threonine (ACG). The sequencing enabled the development of a monospecific PCR-SSP reaction which can be used to discriminate between HLA-B*3924 and other B*39 alleles.

Health issues associated with increasing use of "crack" cocaine among female sex workers in London

OBJECTIVES

To document changes in "crack" cocaine use in the sex industry in London, and to assess health risks associated with the drug.

DESIGN

Two serial cross sectional surveys.

SUBJECTS

Sex workers interviewed in 1989-9 and 1995-6.

MAIN OUTCOME MEASURES

Self reported use of crack cocaine; clinical history of sexually transmitted infection and pregnancy, clinical outcomes.

RESULTS

The proportion of women reporting crack use increased significantly from 22/193 (11%) in 1989-91 to 48/143 (34%) in 1995-6. Women in all the main prostitution sectors reported crack use. Crack users had been working in prostitution for longer, were more likely to have worked on the streets, to inject drugs, and to have a partner who injected. Crack use was associated with termination of pregnancy and with hepatitis C infection. The association with hepatitis C was partially explained by confounding with injecting drug use.

CONCLUSIONS

Crack use is more common and less problematic than clinical presentation suggests. Use has increased over the past decade, and is associated with hepatitis C infection and termination of pregnancy. It is possible that crack use facilitates hepatitis C transmission due to oral lesions from smoking. Crack use can be difficult to identify because of the stigma of being labelled a "crack whore," therefore information on crack might usefully be integrated into general health promotion material on drugs and safer sex.

An HLB-B null allele (B*0808N) caused by a nucleotide deletion in exon 3, found in the family of a bone marrow transplant recipient

We have identified a variant HLA-B allele, B*0808N, segregating through two generations of healthy individuals, whilst HLA typing the family of a bone marrow patient. Serological typing identified a disparity between the father (A1, A3 B7 DR7) and the brother (A1, A2 B56 DR1, DR7) of the patient. Low/medium resolution polymerase chain reaction using sequence-specific primers (PCR-SSP) revealed a B*08 allele undetectable by serological methods. High resolution DNA typing by polymerase chain reaction-sequencing based typing (PCR-SBT), revealed a nucleotide deletion at position 131 (C) in exon 3, the only difference between the new allele and B*0801. The deletion results in a frame shift in the protein coding sequence, introducing a premature termination codon (TGA) in exon 4. Although a B*08 allele is present in these individuals, the deletion prevents correct expression of the antigen on the cell surface.

Identification of the null HLA-A2 allele, A*0232N

We have identified a null HLA-A*02 allele, HLA-A*0232N, by using a combination of serology, flow cytometry, polymerase chain reaction using sequence-specific primers (PCR-SSP) and full-length sequencing. The null HLA-A2 allele was identified in an Asian individual originally typed by serology as an apparently homozygous HLA-A3, B51. Subsequent genotyping by PCR-SSP identified the genotype as HLA-A*0201, *0301, B*51, Cw*1402. The serological type and lack of detectable HLA-A2 was confirmed using monoclonal antibody typing reagents. Flow cytometry studies failed to identify any cell surface HLA-A2 expression on the patient's peripheral blood lymphocytes. Genotyping using a PCR-SSP set designed to detect null alleles revealed the mutation had not been previously described. Full-length sequencing of the allele identified an allele which was subsequently named HLA-A*0232N. This allele is identical to HLA-A*0201 except for a novel point mutation (T for C) at position 493 which creates a premature stop codon. The sequencing enabled the development of a monospecific A*0232N PCR-SSP reaction which was used to screen 973 DNA samples: no further examples of A*0232N were identified.

An analytic method for longitudinal mortality studies

Our knowledge of mortality risks comes largely from longitudinal (cohort) studies. The most commonly used analytic tool is the Cox proportional hazards model for survival analysis. An alternative approach is a simple cross-sectional analysis of person-years. The key to the method is logistic regression, where the outcome variable is lived/died in the given year and the explanatory variables are age, sex, and other potential risk factors. This approach can be used to model any dichotomous outcome and has several important advantages over the more traditional survival analysis. As an example, we compare the two methods using a large data base of patients with spinal cord injury.

Identification of a novel allele, B*15012, by polymerase chain reaction using sequence-specific primers (PCR-SSP) and sequence-based typing

We report here a new allele, B*15012, identified by polymerase chain reaction using sequence-specific primers (PCR-SSP) and sequence-based typing (SBT). B*15012 differs to B*15011 (previously named B*1501) by a single nucleotide, at position 435 of codon 120. B*15011 encodes AAG and B*15012 encodes AAA at codon 120, this difference does not result in an amino acid change.

Identification of an HLA-B7 serological variant and its characterization by sequencing based typing

We have identified an HLA-B*07 variant allele, B*0716, in a Caucasoid cadaver kidney donor. The HLA class I type by polymerase chain reaction using sequence-specific primers (PCR-SSP) was A*01, 32; B*07, 08; Cw*07. Serological typing, using monoclonal and polyclonal anti-HLA antisera, gave disparate results for the B antigens. Monoclonal antibodies identified B7 and B8 antigens but polyclonal antisera recognised only the B8 antigen. PCR using sequencing based typing (PCR-SBT) confirmed the presence of both B*0703 and B*0801 alleles but with a mutation in one of the alleles. The HLA-B*07 allele was isolated by allele-specific PCR and was shown to have a mutation, G-->T, at 292 in exon 2. This mutation changes codon 74, which encodes aspartic acid (GAC) present in all previously identified B*07 alleles, to tyrosine (TAC) in the variant. The serological results suggest that codon 74 is a crucial part of a B7 antigen-specific epitope recognised by tissue typing polyclonal antisera.

Implementation of a clinical pathway system in maternal newborn care: a comprehensive documentation system for outcomes management

This article describes the design, implementation, and evaluation of an interdisciplinary clinical pathway system for maternal newborn care in a perinatal regional referral institution. Core issues in the design of this system are addressed to promote outcomes management and ongoing performance improvement. A discussion of the implementation follows, illustrating the lessons learned, changes made, and associated evaluation. This clinical pathway system has improved communication and collaboration among all disciplines, enhanced the discharge coordination process, and established protocols available to all members of the health care team.

The development of an in-house leg ulcer management course

A description of a course designed to standardise leg ulcer management.