Structure-function studies of the human immunodeficiency virus type 1 matrix protein, p17

The human immunodeficiency virus type 1 (HIV-1) matrix protein, p17, plays important roles in both the early and late stages of the viral life cycle. Using our previously determined solution structure of p17, we have undertaken a rational mutagenesis program aimed at mapping structure-function relationships within the molecule. Amino acids hypothesized to be important for p17 function were mutated and examined for effect in an infectious proviral clone of HIV-1. In parallel, we analyzed by nuclear magnetic resonance spectroscopy the structure of recombinant p17 protein containing such substitutions. These analyses identified three classes of mutants that were defective in viral replication: (i) proteins containing substitutions at internal residues that grossly distorted the structure of recombinant p17 and prevented viral particle formation, (ii) mutations at putative p17 trimer interfaces that allowed correct folding of recombinant protein but produced virus that was defective in particle assembly, and (iii) substitution of basic residues in helix A that caused some relocation of virus assembly to intracellular locations and produced normally budded virions that were completely noninfectious.

Team management of the female athlete triad part 2: optimal treatment and prevention tactics

Multidisciplinary management of the female athlete triad (disordered eating, amenorrhea, and osteoporosis) is optimal, but what exactly does it entail? With the primary care physician as the point person, the healthcare team addresses the underlying causes of disordered eating through such measures as drawing up a contract for returning to play, resolving nutrition issues, exploring psychotherapy options, and, sometimes, prescribing antidepressants. Hormone replacement therapy and conservative or orthopedic intervention for stress fractures may also be required. Communication among the members of the treatment team is crucial, and athletic trainers especially can provide valuable input. Prevention strategies need to involve education of coaches, teachers, trainers, parents, and others who work closely with female athletes.

Team management of the female athlete triad: part 1: what to look for, what to ask

The female athlete triad of disordered eating, amenorrhea, and osteoporosis affects many active women and girls, especially those in sports that emphasize appearance or leanness. Because of the athlete's psychological defense mechanisms and the stigma surrounding disordered eating, physicians may need to ask targeted questions about nutrition habits when assessing a patient who has a stress fracture or amenorrhea, or during preparticipation exams. Carefully worded questions can help. Physical signs and symptoms include unexplained recurrent or stress fracture, dry hair, low body temperature, lanugo, and fatigue. Targeted lab tests to assess nutritional and hormonal status are essential in making a diagnosis that will steer treatment, as are optimal radiologic tests like dual-energy x-ray absorptiometry for assessing bone density.

Improving care for minority children with asthma: professional education in public health clinics

OBJECTIVE

Recent studies have shown that lack of continuing primary care for asthma is associated with increased levels of morbidity in low-income minority children. Although effective preventive therapy is available, many African-American and Latino children receive episodic treatment for asthma that does not follow current guidelines for care. To see if access, continuity, and quality of care could be improved in pediatric clinics serving low-income children in New York City, we trained staff in New York City Bureau of Child Health clinics to provide continuing, preventive care for asthma.

METHODS

We evaluated the impact of the intervention over a 2-year period in a controlled study of 22 clinics. Training for intervention clinic staff was based on National Asthma Education and Prevention Program guidelines for the diagnosis and management of asthma, and included screening to identify new cases and health education to improve family management. The intervention included strong administrative support by the Bureau of Child Health to promote staff behavior change. We hypothesized that after the intervention, clinics that received the intervention would, compared with control clinics, have increased numbers of children with asthma receiving continuing care in the clinics and increased staff use of new pharmacologic and educational treatment methods.

RESULTS

In both the first and second follow-up years, the intervention clinics had greater positive changes than control clinics on measures of access, continuity, and quality of care. For second year follow-up data these include: for access, greater rate of new asthma patients (40/1000 vs 16/1000; P < .01); for continuity, greater percentage of asthma patients returning for treatment 2 years in a row (42% vs 12%; P < .001) and greater annual frequency of scheduled visits for asthma per patient (1.85 vs .88; P < .001); and for quality, greater percentage of patients receiving inhaled beta agonists (52% vs 15%; P < .001) and inhaled antiinflammatory drugs (25% vs 2%; P < .001), and greater percentages of parents who reported receiving patient education on 12 topics from Bureau of Child Health physicians (71% vs 58%; P < .01) and nurses (61% vs 44%; P < .05).

CONCLUSION

We conclude that the intervention substantially increased the Bureau of Child Health staff's ability to identify children with asthma, involve them in continuing care, and provide them with state-of-the-art care for asthma.

Evaluation of magnetic foil and PPT Insoles in the treatment of heel pain

The effect of a magnetic foil placed in the PPT/Rx Firm Molded Insole on the relief of heel pain was determined using the foot function index. Nineteen patients wore the PPT/Rx Firm Molded Insoles with the magnetic foil for 4 weeks and 15 patients wore the same PPT/Rx Firm Molded Insole with no magnetic foil for the same time. Approximately 60% of patients in both groups reported improvement. There was also no significant difference in the improvement between the magnetic foil group and the PPT/Rx Firm Molded Insole group in their scores on the post-treatment foot function index. These results suggest that the PPT/Rx Firm Molded Insole alone was effective in treating heel pain after only 4 weeks. The magnetic foil offered no advantage over the plain insole.

Three-dimensional tumor localization in thick tissue with the use of diffuse photon-density waves

A new approach to three-dimensional tumor localization in turbid media with the use of measurements in a single plane is presented. Optical diffuse photon-density waves are used to probe the turbid medium. Relative amplitudes and phases are measured in the detection plane. Lateral localization is accomplished in the detection plane. With a Fourier optics approach, the scattered wave is reconstructed throughout the volume to provide depth localization. Computer-simulation results that validate this technique are presented. Applications of this technique to multiple tumors and to optical mammography are discussed.

Comparison of Viscoped and PORON for painful submetatarsal hyperkeratotic lesions

A clinical study was performed to evaluate the efficacy of the Viscoped Insole as compared with an 1/8-inch PORON medical materials insole in the treatment of lesser submetatarsal hyperkeratotic callosities. Thirty-five patients, ranging in age from 23 through 61 years (average 42 years) were randomly divided into three groups. All three groups initially had debridement of their submetatarsal callosities. In addition to the debridement, the first group (16 patients) wore a Viscoped Insole for 4 weeks. The patients in the second group wore a PORON insole for 4 weeks. The third group did not receive an insole after their debridement and served as the control. There was a significant improvement in the Viscoped group and the PORON group versus the control group (x2 = 40; p < 0.01) as measured by the foot function index. Insole therapy combined with debridement for submetatarsal hyperkeratoses is more effective than debridement alone.

High-energy ballistic and avulsive facial injuries: classification, patterns, and an algorithm for primary reconstruction

A 17-year experience from 1977 to 1993 with gunshot, shotgun, and high-energy avulsive facial injuries emphasizes the superiority and safety of "ballistic wound" surgical management: (1) immediate stabilization in anatomic position of existing bone, (2) primary closure of existing soft tissue, (3) periodic "second look" serial debridement procedures, and (4) definitive early reconstruction of soft-tissue and bony defects. The series contains 250 gunshot wounds, 53 close-range shotgun wounds, and 15 high-energy avulsive facial injuries. Four general patterns of involvement are noted for both gunshot and shotgun wounds and three for avulsive facial injuries. The treatment algorithm begins with identifying zones of injury and loss for both soft and hard tissue. Gunshot wounds are best classified by the location of the exit wound; shotgun and avulsive facial wounds are classified according to the zone of soft-tissue and bone loss. Treatment, prognosis, and complications vary according to four patterns of gunshot wounds and four patterns of shotgun wounds. Avulsive wounds have not been recommended previously for ballistic wound surgical management. The appropriate management of high-energy avulsive and ballistic facial injuries is best approached by an aggressive treatment program emphasizing initial primary repair of existing tissue, serial conservative debridement, and early definitive reconstruction.

Tissue inhibitor of metalloproteinase-1 messenger RNA expression is enhanced relative to interstitial collagenase messenger RNA in experimental liver injury and fibrosis

Liver fibrosis results from a relative imbalance between synthesis and degradation of matrix proteins. We have previously described release of the protein collagenase inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1), by culture-activated human hepatic stellate cells (HSCs). In this study, we have investigated the relative expression of TIMP-1 and interstitial collagenase in culture-activated rat HSCs and rat models of liver injury and fibrosis. The complementary DNA (cDNA) for rat TIMP-1 was obtained by homology polymerase chain reaction (PCR) and sequenced. By Northern analysis using this probe, TIMP-1 messenger RNA (mRNA) expression was up-regulated with HSC activation by culture on plastic as defined by cellular expression of procollagen-1. Interstitial collagenase mRNA was expressed in early 1. Interstitial collagenase mRNA was expressed in early culture (<4 days) but became undetectable in more activated cells (7-21 days). By activity assay of serum-free cell-conditioned media, TIMP-1 was found to be released in increasingly concentrations with duration of culture on plastic. Expression of TIMP-1 interstitial collagenase, and procollagen-1 mRNAs were studied in rat models of biliary and parenchymal injury (bile duct ligation and CC14 administration) by ribonuclease protein assay. TIMP-1 mRNA expression was increased at 6, 24 hours, and 3 days after bile duct ligation and was also shown to rise in acute CC14 liver injury and remain elevated as the liver became fibrotic. TIMP-1 expression preceded procollagen-1 expression in both models. In contrasts, interstitial collagenase mRNA levels remained similar to control values throughout both models of liver injury. Total cellular RNA from hepatocytes, HSCs, and kupffer cells freshly isolated from livers after acute CC14 injury was subjected to Northern analysis. TIMP-1 transcripts were observed in nonparenchymal cells only. We suggest that increased expression of TIMP-1 relative to interstitial collagenase by HSCs may promote progression of liver fibrosis in these rat models by preventing degradation of secreted collagens.

Identification and management of minimally displaced nasoethmoidal orbital fractures

The management of nasoethmoidal orbital injuries can be difficult. Clinical recognition and options for correction are diverse. Recently we treated several patients with limited facial injuries in which the nasoethmoidal complex "greensticks." Treatment with limited exposure and rigid fixation allows for adequate reduction. Clinical recognition and an outline for treatment of these limited injuries is presented.

Role of mini- and microplate fixation in fractures of the midface and mandible

Le Fort defined the classic weak points of facial fractures. Fractures of the midface and mandible are believed to require management with standard rigid fixation. Recent work has allowed mini- and microplating of multiple fracture fragments into more manageable larger segments for reduction and subsequent plating with rigid fixation to peripheral buttresses. The technique and indications for use are outlined.

Urinary oxalate excretion in premature infants: effect of human milk versus formula feeding

OBJECTIVE

To study urinary oxalate excretion in infants fed human milk versus formula, and to compare urinary calcium oxalate and calcium phosphate saturation in premature infants with term infants and adults.

METHODOLOGY

We measured urinary oxalate-to-creatinine ratio and urinary oxalate concentration in 15 premature infants fed human milk compared to 16 formula-fed premature infants, and in eight human milk-fed term infants compared to 17 formula-fed term infants. We then studied urinary calcium oxalate and calcium phosphate saturations based on our observations of elevated urinary oxalate excretion in premature infants. Urinary calcium oxalate and calcium phosphate saturations were calculated from urinary concentrations of oxalate, calcium, sodium, potassium, chloride, uric acid, magnesium, phosphorus, and urinary pH. We calculated urinary calcium oxalate and calcium phosphate saturations in nine healthy adults and nine formula-fed term infants to establish control values for urinary saturation. Urinary calcium oxalate and calcium phosphate saturations were determined in nine premature infants receiving a glucose and electrolyte solution, 11 premature infants receiving parenteral nutrition, nine formula-fed premature infants, and 11 human milk-fed premature infants.

RESULTS

Urinary oxalate excretion was higher in formula-fed compared to human milk-fed premature infants whether expressed as oxalate-to-creatinine ratio (0.32 +/- 0.04 versus 0.18 +/- 0.03, P < .01) or urinary oxalate concentration (0.047 +/- 0.007 versus 0.022 +/- 0.002 mg/mL, P < .01). Urinary oxalate excretion was higher in formula-fed term infants than in human milk-fed term infants whether expressed as oxalate-to-creatinine ratio (0.14 +/- 0.01 versus 0.07 +/- 0.01, P < .01) or urinary oxalate concentration (0.022 +/- 0.002 versus 0.012 +/- 0.002 mg/mL, P < .01). The urinary calcium oxalate saturation in healthy adults was 2.84 +/- 0.79; the value in formula-fed term infants was 2.12 +/- 0.31. The urinary calcium oxalate saturation was significantly higher in premature infants receiving formula (15.68 +/- 3.15), human milk (15.02 +/- 2.27), or parenteral nutrition (11.38 +/- 2.56) compared to adults or term infants (P < .01). Urinary calcium oxalate saturation in premature infants receiving a glucose and electrolyte solution (2.45 +/- 0.36) was not significantly different from that in adults or term infants. In contrast, urinary calcium phosphate saturation in premature infants as well as term infants and adults was less than 1; precipitation of calcium phosphate is not likely to occur under these conditions.

CONCLUSION

Formula-fed infants have higher urinary oxalate excretion than human milk-fed infants. Premature infants receiving standard nutritional regimens may have urinary calcium oxalate saturation levels at which dissolved calcium oxalate may form nuclei of its solid phase.

Technique for costochondral graft placement

The use of costochondral grafts in the acute trauma setting is controversial. This new technique has recently been utilized in two patients with severe condylar head fractures using a newly designed Synthes AO mesh plate with microscrews (0.8 mm) and 1.5-mm fixation. The technique provides superb rigid fixation. This fixation technique is multifaceted and can be used in all settings of acute and chronic costochondral graft replacement.

Structural similarity between the p17 matrix protein of HIV-1 and interferon-gamma

The human immunodeficiency virus (HIV) matrix protein, p17, forms the outer shell of the core of the virus, lining the inner surface of the viral membrane. The protein has several key functions. It orchestrates viral assembly via targeting signals that direct the gag precursor polyprotein, p55, to the host cell membrane and it interacts with the transmembrane protein, gp41, to retain the env-encoded proteins in the virus. In addition, p17 contains a nuclear localization signal that directs the preintegration complex to the nucleus of infected cells. This permits the virus to infect productively non-dividing cells, a distinguishing feature of HIV and other lentiviruses. We have determined the solution structure of p17 by nuclear magnetic resonance (NMR) with a root-mean square deviation for the backbone of the well-defined regions of 0.9 A. It consists of four helices connected by short loops and an irregular, mixed beta-sheet which provides a positively charged surface for interaction with the inner layer of the membrane. The helical topology is unusual; the Brookhaven protein database contains only one similar structure, that of the immune modulator interferon-gamma.

Transient loss of proteins carrying Kell and Lutheran red cell antigens during consecutive relapses of autoimmune thrombocytopenia

A patient is described in whom two consecutive relapses of autoimmune thrombocytopenic purpura (AITP) were associated with loss of red cell antigens of the Kell and Lutheran blood group systems respectively. During the second relapse the glycoprotein CD44 and to a lesser extent the LW antigen were also depressed. Both relapses were associated with concomitant production of IgG antibody recognizing high-frequency determinants on the corresponding antigen-carrying protein. Blocking of antigen sites by these antibodies was not the cause of reduced antigen expression, because immunoblotting studies showed absence of Kell protein during the first relapse, and Lutheran protein during the second. On both occasions the red cell changes reverted to normal with disappearance of the antibody as the AITP entered remission. There was no evidence of clonal lymphocyte expansion as demonstrated using immunoglobulin JH and T cell receptor beta chain probes.

How to help the athlete with bulimia: practical tips and a case study

Surveys suggest that 8 to 41% of athletes may struggle with binge/purge and bulimic eating behaviors. Many of these athletes with bulimia struggle alone, receiving no professional help for recovery. This article offers effective counseling strategies for nutrition professionals who want to help bulimic athletes. Through a case study of a triathlete who binges, and then purges through compulsive exercise, a nutrition care plan is discussed that addresses the food and weight concerns commonly expressed by athletes with bulimia. The priorities of the care plan are to reduce preoccupation with weight, establish a pattern of regular eating, and address the underlying causes of the binges. The case demonstrates that nutrition counseling is only one part of the treatment program, and emphasizes the importance of developing a team of health professionals to assist athletes with bulimia.

Differential activation of human immunodeficiency virus type 1 and 2 transcription by specific T-cell activation signals

The human immunodeficiency virus type 1 (HIV-1) and HIV-2 enhancers are induced differentially by physiologic T-cell activation signals. In contrast to that of HIV-1, HIV-2 transcription was quite responsive to stimulation of T cells by antigen presentation but weakly induced by tumor necrosis factor alpha. Like tumor necrosis factor alpha, expression of cloned NF-kappa B subunits strongly activated the HIV-1, but not the HIV-2, enhancer. The differences in response to these physiologic T-cell activation pathways may contribute to the differences in persistence of HIV-1 and HIV-2 infection.

Soft-tissue reconstruction of the foot and ankle

Successful reconstruction of the severely injured foot and ankle remains a challenge for the surgeon. Frequently, bone and joint injuries to this area with overlying soft-tissue injuries or losses require the coordinate management by orthopedic and reconstructive specialists. Healthy, well-functioning feet are necessary to perform daily activities. Because of the dense packaging of the specialized interdependent structures of the feet, injuries to this area commonly cause significant (composite) wounds that, if not properly managed, can lead to progressive deformity and disability. Basic principles of wound management, especially those pertaining to open fracture management--wound evaluation, debridement, fracture reduction and fixation, preservation of viable tissues, prevention of infection, early soft-tissue reconstruction, and early bony reconstruction--are applicable in the management of foot and ankle wounds. The unique anatomy of the foot complicates reconstruction by limiting the availability of local tissues. Further reconstructive difficulties arise from the functional demands placed on feet and from the distal relationship of the feet to the rest of the body. Successful reconstruction of the foot is predicated on an intimate knowledge of the unique anatomy of the region, of the functional demands required of the feet, and of reconstructive methods. The simplest appropriate technique for the injured foot that is likely to produce the best outcome should be selected. Reconstructive options from the most simple to the complex include primary closure, healing by secondary intention, grafting, flaps (local and distant), and amputation. As typified by the authors' experience, reconstruction of the soft tissues of the foot and ankle frequently requires more complex methods. Seventy percent of our patients have required free-tissue transfer reconstructions, and an additional 5% have undergone other flap reconstructions.