Synthesis, evaluation, and comparative molecular field analysis of 1-phenyl-3-amino-1,2,3,4-tetrahydronaphthalenes as ligands for histamine H(1) receptors

A series of 1-phenyl-3-amino-1,2,3,4-tetrahydronaphthalenes (1-phenyl-3-aminotetralins, PATs) previously was found to modulate tyrosine hydroxylase activity and dopamine synthesis in rodent forebrain through interaction with a binding site labeled by [(3)H]-(-)-(1R,3S)-trans-H(2)-PAT. Recently, we have discovered that PATs also bind with high affinity to the [(3)H]mepyramine-labeled H(1) receptor in rat and guinea pig brain. Here, we report the synthesis and biological evaluation of additional PAT analogues in order to identify differences in binding at these two sites. Further molecular modifications involve the pendant phenyl ring as well as quaternary amine compounds. Comparison of about 38 PAT analogues, 10 structurally diverse H(1) ligands, and several other CNS-active compounds revealed no significant differences in affinity at [(3)H]-(-)-trans-H(2)-PAT sites versus [(3)H]mepyramine-labeled H(1) receptors. These results, together with previous autoradiographic brain receptor-mapping studies that indicate similar distribution of [(3)H]-(-)-trans-H(2)-PAT sites and [(3)H]mepyramine-labeled H(1) receptors, suggest that both radioligands label the same histamine H(1) receptors in rodent brain. We also report a revision of our previous comparative molecular field analysis (CoMFA) study of the PAT ligands that yields a highly predictive model for 66 compounds with a cross-validated R(2) (q(2)) value of 0.67. This model will be useful for the prediction of high-affinity ligands at radiolabeled H(1) receptors in mammalian brain.

Putative sigma(3) sites in mammalian brain have histamine H(1) receptor properties: evidence from ligand binding and distribution studies with the novel H(1) radioligand [(3)H]-(-)-trans-1-phenyl-3-aminotetralin

A novel phenylaminotetralin (PAT) radioligand, [(3)H]-(1R, 3S)-(-)-trans-1-phenyl-3-dimethylamino-1,2,3,4-tetrahydronaphthalene ([(3)H]-[-]-trans-H(2)-PAT), is shown here to label a saturable (B(max)=39+/-6 fmol/mg protein) population of sites with high affinity (K(d)=0.13+/-0.03 nM) in guinea pig brain. Consistent with previous studies which showed that PATs stimulate catecholamine (dopamine) synthesis in rat striatum, autoradiographic brain receptor mapping studies here indicate that [(3)H]-(-)-trans-H(2)-PAT-labeled sites are highly localized in catecholaminergic nerve terminal fields in hippocampus, nucleus accumbens, and striatum in guinea pig brain. Competition binding studies with a broad range of CNS receptor-active ligands and CNS radioreceptor screening assays indicate that the pharmacological binding profile of brain [(3)H]-(-)-trans-H(2)-PAT sites closely resembles histamine H(1)-type receptors. Comparative studies using the histamine H(1) antagonist radioligand, [(3)H]mepyramine, indicate that the H(1) ligand binding profile and guinea pig brain distribution of H(1) receptors and [(3)H]-(-)-trans-H(2)-PAT sites are nearly identical; moreover, both sites have about 40-fold stereoselective affinity for (-)- over (+)-trans-H(2)-PAT. These results are discussed in light of previous studies which suggested that PATs stimulate dopamine synthesis through interaction with a novel sigma-type (sigma(3)) receptor in rodent brain; it now appears instead that PATs represent a new class of ligands for brain histamine H(1) receptors that can be stereoselectively labeled with [(3)H]-(-)-trans-H(2)-PAT.

Observation of splenic trauma: when is a little too much?

A 12-year-old boy was treated conservatively for a grade II splenic laceration. On discharge, he was instructed to avoid contact sports, running, and strenuous physical activity. Thirty-eight days later, after diving off the side of a swimming pool, he had abdominal pain, nausea, and diaphoresis. On admission, he was hemodynamically unstable. Results of a diagnostic lavage showed gross blood. At laparotomy, a fractured spleen was found, and splenectomy was performed. He recovered without complication. This case questions the activity restrictions placed on patients with conservatively managed splenic trauma. Avoidance of only contact sports and heavy exertion may be inadequate.

Does early ultrasonography affect management of pediatric appendicitis? A prospective analysis

BACKGROUND

Appendicitis remains a difficult diagnosis in children. Ultrasonography is increasingly used for the diagnosis of appendicitis, although the proper clinical role for this test remains unclear.

METHODS

To evaluate the clinical utility of ultrasonography in appendicitis, the authors analyzed prospectively all children evaluated for possible appendicitis from January 1 through December 31, 1997. Children with a high clinical suspicion of appendicitis were referred for surgery (n = 122). Children with equivocal findings of appendicitis were referred for early ultrasonography (EUS) and formed the study cohort (n = 103). An initial management plan was made to operate or observe each patient, and a risk of appendicitis (doubtful, possible, probable) was assigned by a pediatric surgery fellow. EUS was then performed, and its effect on management was assessed.

RESULTS

Using clinical judgment to operate at initial presentation, the sensitivity was 38% and specificity was 95%. Using EUS alone, the sensitivity was 87% and specificity was 88%. The management of 30 of 103 patients (30%) was changed after EUS, including a decision to operate in 28 patients and a decision not to operate in two patients.

CONCLUSIONS

EUS appears to have substantial clinical utility in children with equivocal findings of appendicitis, and its use complements the clinical management. The use of EUS can improve patient care and reduce hospital resource utilization.

Inhibition of plant-pathogenic fungi by a corn trypsin inhibitor overexpressed in Escherichia coli

The cDNA of a 14-kDa trypsin inhibitor (TI) from corn was subcloned into an Escherichia coli overexpression vector. The overexpressed TI was purified based on its insolubility in urea and then refolded into the active form in vitro. This recombinant TI inhibited both conidium germination and hyphal growth of all nine plant pathogenic fungi studied, including Aspergillus flavus, Aspergillus parasiticus, and Fusarium moniliforme. The calculated 50% inhibitory concentration of TI for conidium germination ranged from 70 to more than 300 microgram/ml, and that for fungal growth ranged from 33 to 124 microgram/ml depending on the fungal species. It also inhibited A. flavus and F. moniliforme simultaneously when they were tested together. The results suggest that the corn 14-kDa TI may function in host resistance against a variety of fungal pathogens of crops.

Distribution of antifungal proteins in maize kernel tissues using immunochemistry

This study examined the distribution of two antifungal proteins, ribosome-inactivating protein (RIP) and zeamatin, in maize kernel tissues. Proteins were extracted from endosperm (including aleurone layer) and embryo tissues of imbibed maize kernels. Western blot analyses revealed that RIP-like protein was present at higher levels in endosperm than in embryo tissues, whereas zeamatin-like protein was more concentrated in embryo tissues than in endosperm tissues. However, there were three protein bands in the endosperm and two bands in the embryo that reacted to anti-RIP antibody in Western blot analyses. Tissue prints were conducted to localize the antifungal proteins. Imbibed kernels were cut longitudinally and transversely and blotted onto nitrocellulose membranes. Using antibodies against maize RIP and zeamatin, RIP was found primarily in the aleurone layer of the endosperm and glandular layer of scutellum, whereas zeamatin was located mainly in the kernel embryo. These results provide insight into the potential functions of these antifungal proteins, especially since the presence of RIP and zeamatin within maize kernels uniquely protects kernels from pathogens.

Advances in the Development of Host Resistance in Corn to Aflatoxin Contamination by Aspergillus flavus

ABSTRACT Aflatoxins are toxic, highly carcinogenic secondary metabolites of Aspergillus flavus and A. parasiticus, which when produced during fungal infection of a susceptible crop in the field or after harvest contaminate food and feed and threaten human and animal health. Although there are several management strategies that may reduce aflatoxin contamination of corn, the preeminent strategy for elimination of aflatoxin is to develop preharvest host resistance to aflatoxin accumulation. This strategy has gained even greater prominence due to recent discoveries of natural resistance in corn that can be exploited in plant-breeding strategies. The ability to identify resistant corn genotypes has been enhanced by the development of a laboratory kernel-screening assay and by a strain of A. flavus genetically engineered to produce beta-glucuronidase, an enzyme whose activity can be monitored to assess the degree of fungal infection in kernels. Investigations of resistant corn genotypes have associated kernel pericarp wax characteristics with resistance, identified kernel proteins associated with resistance to and inhibition of fungal growth or aflatoxin biosynthesis, and identified chromosome regions associated with resistance to Aspergillus ear rot and aflatoxin production. Such research advances could lead, in the near future, to commercially available, agronomically acceptable corn lines with multiple preharvest resistances to aflatoxin contamination.

Pseudechetoxin: a peptide blocker of cyclic nucleotide-gated ion channels

Ion channels activated by the binding of cyclic nucleotides first were discovered in retinal rods where they generate the cell's response to light. In other systems, however, it has been difficult to unambiguously determine whether cyclic nucleotide-dependent processes are mediated by protein kinases, their classical effector enzymes, or cyclic nucleotide-gated (CNG) ion channels. Part of this difficulty has been caused by the lack of specific pharmacological tools. Here we report the purification from the venom of the Australian King Brown snake of a peptide toxin that inhibits current through CNG channels. This toxin, which we have named Pseudechetoxin (PsTx), was purified by cation exchange and RP-HPLC and has a molecular mass of about 24 kDa. When applied to the extracellular face of membrane patches containing the alpha-subunit of the rat olfactory CNG channel, PsTx blocked the cGMP-dependent current with a Ki of 5 nM. Block was independent of voltage and required only a single molecule of toxin. PsTx also blocked CNG channels containing the bovine rod alpha-subunit with high affinity (100 nM), but it was less effective on the heteromeric version of the rod channel (Ki approximately 3 microM). We have obtained N-terminal and partial internal sequence data and the amino acid composition of PsTx. These data indicate that PsTx is a basic protein that exhibits some homology with helothermine, a toxin isolated from the venom of the Mexican beaded lizard. PsTx promises to be a valuable pharmacological tool for studies on the structure and physiology of CNG channels.

Diabetic and Nondiabetic Gastroparesis

Nutritional support is essential in treating patients with gastroparesis. Initially, dietary changes should be instituted to reduce extra fat and bulk, and patients should be encouraged to eat frequent small meals with liquid supplementation. Enteral feeding should be introduced in the event of weight loss or persistent vomiting. Medical therapy is usually necessary early in treatment. Cisapride is the initial agent of choice and may be combined with an antiemetic agent, such as promethazine or chlorpromazine or, if side effects occur, ondansetron and granesitron. If cisapride is ineffective or contraindicated, metoclopramide is a reasonable option, though limited by side effects. Erythromycin is useful in the acute treatment of postoperative ileus and hospitalized gastroparetic patients, but its role is limited based on concerns about poor long-term effectiveness and antimicrobial resistance. Once domperidone becomes available in the United States, it will be useful for its promotility and antiemetic qualities. Combination therapy should be considered if monotherapy with cisapride or metoclopramide alone is ineffective. While not yet well studied, combination therapy has the potential to offer dramatic benefit for patients with refractory gastroparesis. Metoclopramide may be added to cisapride for patients with breakthrough symptoms or refractory chronic symptoms. Other combinations include metoclopramide with erythromycin, domperidone with cisapride, and domperidone with erythromycin. In the future, gastric pacing may become an effective option for patients not responding to medical therapy. Total gastrectomy should be performed only for end-stage gastroparesis when all other therapy has failed. Both procedures should be reserved for centers that specialize in severe gastric motility disorders.

Care of the surgical intensive care nursery graduate. The primary care pediatrician's perspective

Care of the intensive care nursery graduate may be quite challenging. It is important that primary care pediatricians become familiar with the complications unique to surgical patients so that they may properly prepare and educate parents and provide appropriate long-term follow-up for these often complex patients. Maintenance of a close relationship with the pediatric surgeon with an open line of communication regarding the approach to various surgical problems facilitates the effective integration of the intensive care nursery graduate into the primary care pediatrician's practice and provides the foundation for a successful clinical outcome.

The promoter of the plant defensin gene PDF1.2 from Arabidopsis is systemically activated by fungal pathogens and responds to methyl jasmonate but not to salicylic acid

The plant defensin PDF1.2 has previously been shown to accumulate systemically via a salicylic acid-independent pathway in leaves of Arabidopsis upon challenge by fungal pathogens. To further investigate the signalling and transcriptional processes underlying plant defensin induction, a DNA fragment containing 1184 bp and 1232 bp upstream of the transcriptional and translational start sites, respectively, was cloned by inverse PCR. To test for promoter activity this DNA fragment was linked to the beta-glucuronidase (GUS)-encoding region of the UidA gene as a translational fusion and introduced into Arabidopsis ecotype C-24. Challenge of the transgenic plants with the fungal pathogens Alternaria brassicicola and Botrytis cinerea resulted in both local and systemic induction of the reporter gene. Wounding of the transgenic plants had no effect on GUS activity. Treatment of the transgenic plants with either jasmonates or the active oxygen generating compound paraquat strongly induced the reporter gene. In contrast, neither salicylate nor its functional analogues 2,6-dichloroisonicotinic acid and 1,2,3-benzothiodiazole-7-carbothioic acid S-methyl ester resulted in reporter gene induction. These results are consistent with the existence of a salicylic acid-independent signalling pathway, possibly involving jasmonates as regulators, that is triggered by pathogen challenge but not by wounding. The transgenic plants containing the PDF1.2-based promoter-reporter construct will provide useful tools for future genetic dissection of this novel systemic signalling pathway.

Movement of gating machinery during the activation of rod cyclic nucleotide-gated channels

In the visual and olfactory systems, cyclic nucleotide-gated (CNG) ion channels convert stimulus-induced changes in the internal concentrations of cGMP and cAMP into changes in membrane potential. Although it is known that significant activation of these channels requires the binding of three or more molecules of ligand, the detailed molecular mechanism remains obscure. We have probed the structural changes that occur during channel activation by using sulfhydryl-reactive methanethiosulfonate (MTS) reagents and N-ethylmaleimide (NEM). When expressed in Xenopus oocytes, the alpha-subunit of the bovine retinal channel forms homomultimeric channels that are activated by cGMP with a K1/2 of approximately 100 microM. Cyclic AMP, on the other hand, is a very poor activator; a saturating concentration elicits only 1% of the maximum current produced by cGMP. Treatment of excised patches with MTS-ethyltrimethylamine (MTSET) or NEM dramatically potentiated the channel's response to both cyclic nucleotides. After MTSET treatment, the dose-response relation for cGMP was shifted by over two orders of magnitude to lower concentrations. The effect on channel activation by cAMP was even more striking. After modification, the channels were fully activated by cAMP with a K1/2 of approximately 60 microM. This potentiation was abolished by conversion of Cys481 to a nonreactive alanine residue. Potentiation occurred more rapidly in the presence of saturating cGMP, indicating that this region of the channel is more accessible when the channel is open. Cys481 is located in a linker region between the transmembrane and cGMP-binding domains of the channel. These results suggest that this region of the channel undergoes significant movement during the activation process and is critical for coupling ligand binding to pore opening. Potentiation, however, is not mediated by the recently reported interaction between the amino- and carboxy-terminal regions of the alpha-subunit. Deletion of the entire amino-terminal domain had little effect on potentiation by MTSET.

Pediatric head and neck lesions

Commonly encountered head and neck lesions in children are described with an emphasis on evaluation, diagnosis, and treatment. Congenital lesions typically require excision, although hemangiomas usually resolve spontaneously. Acute suppurative lymphadenitis is common and readily diagnosed. Chronic lymphardenitis remains a diagnostic challenge and must be differentiated from malignancy. Lesions that do not respond to antibiotics should be biopsied to exclude neoplasms.

Training the trainers: substance abuse screening and intervention

OBJECTIVE

Screening and brief intervention for substance abuse is effective yet underutilized by primary care physicians. This article reports on Project SAEFP (Substance Abuse Education for Family Physicians), which aimed to enhance the clinical and teaching skills and activities of U.S. family practice residency faculty.

METHOD

Ten five-day workshops were designed and administered for 165 participants. Evaluation data included measures of participant satisfaction and pre-workshop and twelve-month post-workshop measures of the frequency of teaching, consulting, and clinical activities, and the attainment of self-identified teaching goals.

RESULTS

The participants were very satisfied with the workshops. They improved significantly in the key outcome measures.

CONCLUSIONS

Several workshops may have contributed to the apparent success of Project SAEFP. Attributes of the workshops which might have facilitated their success were their duration, funding, frequency of offering, collegial learning environment, opportunities for active learning, emotionally moving exposure to recovering individuals, focus on how to modify curriculum at participant residency programs, availability of family physician role models as faculty, and readily usable instructional materials. Planners of interventions for physician educators might profit from similar attention to these attributes.

Primary care practice adherence to National Cholesterol Education Program guidelines for patients with coronary heart disease

BACKGROUND

Clinical trials demonstrate significant benefit from cholesterol management for patients with cardiovascular disease (CVD). National guidelines recommending goals for screening and treatment were published in 1993 and widely disseminated. This study examines cholesterol screening and management by primary care physicians after the guidelines were released.

METHODS

Medical records and patient surveys provided data for 603 patients with CVD, aged 27 to 70 years, from 45 practices in 4 states during 1993 to 1995. Physician surveys measured estimated performance and other variables. Physician and patient factors associated with adherence, or lack of adherence, to national guidelines were examined using univariate and multivariate analyses.

RESULTS

A total of 199 patients (33%) with CVD were not screened with lipid panels, 271 patients (45%) were not receiving dietary counseling, and 404 (67%) were not receiving cholesterol medication. Only 84 patients (14%) with CVD had achieved the recommended low-density lipoprotein level of less than 2.58 mmol/L (100 mg/dL) and 302 (50%) had triglyceride levels lower than 2.26 mmol/L (200 mg/dL). Patients with a revascularization history and higher low-density lipoprotein and/or triglyceride levels were more likely to receive treatment, but other patient factors, including CVD risk factors, did not predict treatment. Physician specialty was not associated with differences in treatment, but physicians in practice for fewer years ordered more lipid panels.

CONCLUSIONS

Most patients with CVD in primary care were not receiving cholesterol screening and management as recommended by the National Cholesterol Education Program guidelines in the 2 years after their release. Increasing cholesterol screening and treatment should be a priority for practice quality improvement and could result in significant reductions in CVD events for high-risk patients.

Resistance to Aspergillus flavus in Corn Kernels Is Associated with a 14-kDa Protein

ABSTRACT Corn genotypes resistant or susceptible to Aspergillus flavus were extracted for protein analysis using a pH 2.8 buffer. The profile of protein extracts revealed that a 14-kDa protein is present in relatively high concentration in kernels of seven resistant corn genotypes, but is absent or present only in low concentration in kernels of six susceptible ones. The N-terminal sequence of this 14-kDa protein showed 100% homology to a corn trypsin inhibitor. The 14-kDa protein purified from resistant varieties also demonstrated in vitro inhibition of both trypsin activity and the growth of A. flavus. This is the first demonstration of antifungal activity of a corn 14-kDa trypsin inhibitor protein. The expression of this protein among tested genotypes may be related to their difference in resistance to A. flavus infection and subsequent aflatoxin contamination.

Protein profiles and antifungal activities of kernel extracts from corn genotypes resistant and susceptible to Aspergillus flavus

Mechanisms of resistance to infection by the fungus Aspergillus flavus and accumulation of aflatoxin were studied in kernels of resistant (GT-MAS:gk, Mp420) and susceptible ( Pioneer 3154, Deltapine G-4666) corn genotypes. Proteins from kernel extracts of corn genotypes were analyzed by several methods of polyacrylamide gel electrophoresis. Consistent differences in protein profiles were detected among genotypes. Several proteins were unique to or present in greater concentration in resistant genotypes, whereas others were present only in susceptible genotypes. Extracts of resistant kernels showed markedly greater antifungal activity against A. flavus than did susceptible kernel extracts. Results from the present study suggest a role for kernel proteins in resistance to A. flavus infection and aflatoxin contamination in corn genotypes.

The prevalence and detection of substance use disorders among inpatients ages 18 to 49: an opportunity for prevention

BACKGROUND

Previous studies have found that substance use disorders are prevalent among inpatients of general medical hospitals. These studies were limited in the validity of their measures, their failure to distinguish between current and lifetime disorders, or their lack of attention to drugs other than alcohol.

METHODS

The current study used validate diagnostic instruments to measure current and lifetime alcohol and other drugs abuse and dependence among patients ages 18 through 49. Additionally, this study assessed the sensitivity and specificity of four substance abuse screening questions. Patients were recruited from the general medical, general surgery, and orthopedics services of a university hospital in Madison, Wisconsin. The sample included 363 patients, or 86.4% of those recruited.

RESULTS

The current and lifetime prevalence rates of substance use disorders were 21.8 and 49.6%, respectively. The prevalence rates of current problems were 16.3%, alcohol only; 2.5%, other drugs only; and 3.0%, alcohol and other drugs. Males had nearly a 30% current prevalence of current substance use disorders. The CAGE Questions Adapted to Include Drugs exhibited 70.9% sensitivity and 75.7% specificity.

CONCLUSIONS

At one hospital, and perhaps at others, an alcohol and drug screening, assessment, and intervention program may have the potential to prevent future health and social problems.

Germination induces accumulation of specific proteins and antifungal activities in corn kernels

ABSTRACT This study examined protein induction and accumulation during imbibition and germination of corn kernels, as well as antifungal activities of extracts from germinating kernels against Aspergillus flavus and Fusarium moniliforme. Genotypes studied included GT-MAS:gk and Mp420, which are resistant to A. flavus infection and aflatoxin accumulation, and Pioneer 3154 and Deltapine G-4666, which are susceptible to A. flavus infection and aflatoxin accumulation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis resolved five protein bands that were present at higher concentrations in germinated kernels than in nongerminated kernels. Western blot analyses revealed that one of these proteins reacted with the 22-kDa zeamatin antiserum, and a zeamatin-like protein accumulated to a higher concentration in germinated kernels. Two protein bands from dry kernels that reacted with ribosome-inactivating protein (RIP) antiserum were identified as the 32-kDa proRIP-like form and an 18-kDa peptide of the two peptides that form active RIP. However, in germinated kernels, two protein bands that reacted with RIP antiserum were identified as two RIP-like peptides with a molecular mass of approximately 18 and 9 kDa. Purified RIP and zeamatin from corn inhibited growth of A. flavus. Bioassays of germinated kernel extracts from all four genotypes exhibited antifungal activity against A. flavus and F. moniliforme, with extracts from the susceptible genotypes showing greater inhibition zones. This study provides evidence of protein induction in corn kernels during imbibition or the early stages of germination, and the induced proteins may be related to our previous findings of germination-associated resistance in the corn kernel, especially in the susceptible kernels.

Proteolytic activity in human burn wounds

Wound healing is the result of a dynamic balance between synthetic and degradative processes. After a burn, proteolytic activity increases at the wound site. Excised burn wounds and donor skin were examined from 20 pediatric burn patients, to determine which of two classes of neutral proteinases, serine or metalloproteinases, accounts for the majority of this proteolytic activity in these tissues; to examine messenger RNA expression of three of the principal enzymes and inhibitors of this class; and to measure enzymatic activity of two of these metalloproteinases. The majority of the increased proteolysis was due to metalloproteinases. By polymerase chain reaction assays, messenger RNAs for matrix metalloproteinase-1, -3, and -9 were strongly expressed in burn tissue and absent or weakly expressed in unburned skin. Messenger RNA for tissue inhibitor of metalloproteinase-1 and -2 was consistently present in burned and unburned skin. By zymography, there was a significant increase in matrix metalloproteinase-2 (twofold to threefold) and matrix metalloproteinase-9 (20- to 30-fold) activity in burned versus unburned skin. We suggest that postburn there is an upregulation of some matrix metalloproteinases that exceeds the level of inhibitors with the net result of an increase in proteolysis in burned tissue. This increased proteolysis may play a role in wound repair and scar formation.

Molecular genetic evidence for the involvement of a specific polygalacturonase, P2c, in the invasion and spread of Aspergillus flavus in cotton bolls

Isolates of Aspergillus flavus can be differentiated based on production of the polygalacturonase P2c. One group of isolates produces P2c, whereas the other group does not. In general, the group that produces P2c causes more damage and spreads to a greater extent in cotton bolls than those isolates that do not produce P2c. To determine whether P2c contributes to disease, the expression of pecA, the gene previously determined to encode P2c, was genetically altered. Adding the pecA gene to a strain previously lacking the gene resulted in the ability to cause significantly more damage to the intercarpellary membrane and the ability spread to a greater extent within the adjacent locule compared to the abilities of a control transformant. Conversely, eliminating the expression of pecA by targeted disruption caused a significant reduction in aggressiveness compared to that of a nondisrupted control transformant. These results provide direct evidence that P2c contributes to the invasion and spread of A. flavus during infection of cotton bolls. However, other factors not evaluated in this study also contribute to aggressiveness.

In vivo comparison of two enteric-pouch power transformers for circulatory support

A defunctionalized ileal pouch is thin-walled (1-2 mm), well perfused (blood flow, 0.3-1.0 ml/g/min), and tactile-insensitive. If fixed within the abdominal wall and provided with a miniature stoma for primary wire entry, the heat dissipating capacity and achievable geometries could facilitate small efficient intra- to extracorporeal power transformers with virtually complete magnetic flux containment. Two transformers (A, weighing 102 gm with dual ferrite cores, intraluminal primary and extraluminal secondary each with 10 turns on its own crescentic ferrite core, 90 kHz, coupling coefficient k = 0.90-0.96; and B, 68 gm, a single flexible torroidal magnetic metallic tape core with attached 11 turn primary and free 14 turn serosal secondary, 14.7 kHz, k = 0.99) met the electrical and anatomic requirements. Each was implanted (minilaparotomy, coil-pouch fixation within abdominal musculature) in 4 dogs for 14-21 days to test the operative feasibility, electrical function, warming, and flux containment. For canine testing, wires were tunneled to a chewing-inaccessible site. Neither tissue necrosis, infection, provokable interference from contiguous metal, nor coil displacement were observed; secretions were retained in Group A pouches only. The mean power transmissions for the transformers were A: 24.90 +/- 1.50 W and B: 24.92 +/- 0.89 W, after operation for 7 days or more. The mean efficiencies were A: 75.6 +/- 0.1% total DC/DC, 96.2% coils and B: 80.4 +/- 0.1% total DC/DC, 96.2% coils. The peak skin surface magnetic fluxes for transformers A and B, both trivial at 1.7 and 1.2 G, respectively, were similar. Warming was 0.62 +/- 0.30 degrees C in Group A and 0.73 +/- 0.19 degrees C in Group B. The probability values were p < 0.5 (NS) for DC/DC efficiency and p > 0.10 (NS), for A versus B in all other areas of comparison. Observations for both were encouraging. Transformer B, with less mass, lower frequency, higher efficiency, and intrinsic invulnerability to displacement, was selected for longer term evaluation.

Iron burns to the hand in the young pediatric patient: a problem in prevention

Iron burns to the hand may result in both functional and cosmetic deformities in the young pediatric patient. To gain a better understanding of these injuries in terms of demographics, treatment, and outcome, and to address possible measures for prevention, the medical records of 82 pediatric patients suffering iron burns to the hand during the period 1987 to 1993 were reviewed. Iron burns to the hand occurred most commonly in male children less than 2 years of age. Most were minor partial-thickness burns that were treated in the outpatient setting with no adverse sequelae. Fifteen percent of patients, however, sustained full-thickness burns that required grafting. Ten percent of patients developed complications including hypertrophic scarring and scar contractures requiring surgical release. Socioeconomic factors and parental inexperience appeared to play a significant role, as most of these injuries occurred in low-income, single-parent, single-child households. Most injuries were unintentional, however, many were caused by carelessness or neglect. Abuse was suspected or proven in 7% of cases. Parents may be unaware of the consequences of leaving a child unattended in the presence of a hot iron. The incidence of these injuries could be reduced effectively by improved public awareness of the problem and education in prevention.