Gender-Affirming Care for Older Transgender and Gender Diverse Adults

In the United States, it is estimated that 0.3% of Americans aged 65 and older, or almost 172,000 individuals, identify as transgender. Aging comes with a unique set of challenges and experiences for this population, including health care disparities, mental health concerns, and social isolation. It is crucial for clinicians to use a patient-centered and trauma-informed care approach to address their specific needs and provide evidence-based quality health care, including preventive screenings, mental health support, and advocating for legal protections.

Cardiovascular Disease Risk Estimation for Transgender and Gender-Diverse Patients: Cross-Sectional Analysis of Baseline Data From the LITE Plus Cohort Study

Introduction

Approximately 2% of the U.S. population identifies as transgender, and transgender people experience disproportionate rates of cardiovascular disease mortality. However, widely used cardiovascular disease risk estimators have not been validated in this population. This study sought to determine the impact on statin therapy recommendations using 3 different approaches to operationalizing sex in the American Health Association/American College of Cardiology Pooled Cohort Equation Risk Estimator.

Methods

This is a cross-sectional analysis of baseline clinical data from LITE Plus, a prospective cohort study of Black and/or Latina transgender women with HIV. Data were collected from October 2020 to June 2022 and used to calculate Pooled Cohort Equation scores.

Results

The 102 participants had a mean age of 43 years. A total of 88% were Black, and 18% were Latina. A total of 79% were taking gender-affirming hormones. The average Pooled Cohort Equation risk score was 6% when sex assigned at birth was used and statins would be recommended for the 31% with Pooled Cohort Equation >7.5%. The average risk score was 4%, and 18% met the criteria for statin initiation when current gender was used; the mean risk score was 5%, and 22% met the criteria for statin initiation when current hormone therapy was used.

Conclusions

Average Pooled Cohort Equation risk scores vary substantially depending on the approach to operationalizing the sex variable, suggesting that widely used cardiovascular risk estimators may be unreliable predictors of cardiovascular disease risk in transgender populations. Collection of sex, gender, and hormone use in longitudinal studies of cardiovascular health is needed to address this important limitation of current risk estimators.

HIV prevalence among transmasculine individuals at a New York City Community Health Centre: a cross-sectional study

INTRODUCTION

Multiple studies have demonstrated elevated incidence and prevalence of HIV among transgender women; however, few studies have been conducted among transmasculine individuals. HIV prevalence among transgender men in the United States is estimated to be 0-4%; however, there have not been any US studies examining HIV prevalence that stratify by the gender of sexual partners. The aim of this research was to examine HIV prevalence and its association with socio-demographic and other factors, including the gender of sexual partners and receipt of gender-affirming care (hormones/surgery), among transmasculine individuals at the Callen-Lorde Community Health Center in New York City.

METHODS

The Transgender Data Project was an Institutional Review Board-approved retrospective chart review of all transgender and gender diverse clients at the clinic, ages 18+, between 1 January 2009 and 12 December 2010. Charts were reviewed manually. Data included birth sex, gender, race/ethnicity, education, employment, housing, insurance status, gender of sexual partners, HIV screening and status, and receipt of gender-affirming care. Bivariate and multivariable logistic regression models were used to assess the association between HIV status and other variables.

RESULTS AND DISCUSSION

Five hundred and seventy-seven transmasculine individuals, mean age 32.1 years (18.3-70.5), were included in this analysis. A small majority were White (55% White, 13.9% Black and 11.7% Hispanic). The majority, 78.9%, had received hormones (testosterone) and 41.6% had received at least one gender-affirming surgery. The HIV screening rate was 43.4%. HIV prevalence was 2.8%, (95% CI: 1.13%, 5.68%) among those screened, notably higher than the US population prevalence. HIV prevalence was highest among transmasculine individuals who had sex exclusively with cisgender men (11.1%). In the multivariable model (age, education and gender of sexual partners), the adjusted odds ratio of HIV for those who had sex exclusively with cisgender male partners compared to no cisgender male partners was 10.58 (95% CI: 1.33, 84.17).

CONCLUSIONS

Although HIV prevalence has been estimated to be low among transgender men, the analysis found heterogeneous results when stratified by gender of sexual partners. The results underscore the need to understand sexual risk among transmasculine individuals and to disaggregate HIV data for those having sex with cisgender men, thus also allowing for better inclusion in HIV prevention efforts.

“Focus more on what’s right instead of what’s wrong:” research priorities identified by a sample of transgender and gender diverse community health center patients

Background

Transgender and gender diverse (TGD) individuals disproportionately experience disparate health outcomes compared to their cisgender peers. This study aimed to collect qualitative data from a sample of TGD community health center patients on health research priorities to inform future TGD-centered research in the field of TGD health.

Methods

Between September–November of 2018, four focus groups (two groups in Boston MA, two in New York NY; n = 28 individuals) were held to evaluate community-identified TGD health research priorities with a sample of patients from two community health centers. Thematic analyses were conducted and restricted to social factors impacting health. Findings were incorporated into the development of The LEGACY Project, a longitudinal cohort of TGD patients, assessing the impact of gender-affirming care on health outcomes.

Results

Cross-cutting themes about TGD research priorities pertaining to social factors and health included: (1) Embodiment: understanding and investigating the complex and intersectional lived experiences of TGD individuals; (2) Social determinants of health: the impact of structural and interpersonal stigma on TGD health; and (3) Resiliency and health promoting factors: the need to expand public health research beyond disparities to assess resiliency and health promotion in TGD communities.

Conclusions

Participants identified investigating the impact of social influences on health as a research priority for TGD patients. Recalibrating field norms from individual researcher priorities to TGD population-driven research will help ensure investigators address topics that may otherwise be missed or overlooked and may optimize the reach and impact of research in TGD health.

Brief Report: Transgender Women and Preexposure Prophylaxis Care: High Preexposure Prophylaxis Adherence in a Real-World Health Care Setting in New York City

BACKGROUND

Transgender women and trans feminine individuals (TGW/TFI) are a high priority population for the provision of HIV preexposure prophylaxis (PrEP) care within the United States, but there is limited research that focuses specifically on PrEP adherence within this population.

SETTING

Observational study of patients prescribed PrEP at a community-based health center.

METHODS

We enrolled 100 TGW/TFI PrEP patients at a community health center during clinic visits. Adherence data were collected at 3 time points, using self-report surveys, patient interviews, and urine assays measuring tenofovir. Data were summarized descriptively.

RESULTS

The sample was diverse in age, race/ethnicity, and socioeconomic characteristics. Participants demonstrated strong PrEP adherence; at least 80% of the sample reported 90% or greater adherence at each time point. Concordance between self-report and urine assay was high. Among patients who reported taking PrEP within the past 48 hours, 82%-92% had detectable urine tenofovir. However, many patients reported PrEP stop periods of 4 or more days (28%-39% per time point).

CONCLUSIONS

Our data highlight TGW/TFI's capacity to adhere to daily PrEP and sustain PrEP use over time. The concordance between patient self-report and urine TFV levels suggest that providers can trust patient reports of PrEP adherence behavior and support the use of adherence conversations in clinical settings, without the need for point of care biological monitoring. Findings also underscore the importance of continued attention to drivers of PrEP stops at the patient, clinic, and systems levels and the development of strategies that support sustained PrEP use.

Brief Report: Transgender Women and Preexposure Prophylaxis Care: High Preexposure Prophylaxis Adherence in a Real-World Health Care Setting in New York City

BACKGROUND

Transgender women and trans feminine individuals (TGW/TFI) are a high priority population for the provision of HIV preexposure prophylaxis (PrEP) care within the United States, but there is limited research that focuses specifically on PrEP adherence within this population.

SETTING

Observational study of patients prescribed PrEP at a community-based health center.

METHODS

We enrolled 100 TGW/TFI PrEP patients at a community health center during clinic visits. Adherence data were collected at 3 time points, using self-report surveys, patient interviews, and urine assays measuring tenofovir. Data were summarized descriptively.

RESULTS

The sample was diverse in age, race/ethnicity, and socioeconomic characteristics. Participants demonstrated strong PrEP adherence; at least 80% of the sample reported 90% or greater adherence at each time point. Concordance between self-report and urine assay was high. Among patients who reported taking PrEP within the past 48 hours, 82%-92% had detectable urine tenofovir. However, many patients reported PrEP stop periods of 4 or more days (28%-39% per time point).

CONCLUSIONS

Our data highlight TGW/TFI's capacity to adhere to daily PrEP and sustain PrEP use over time. The concordance between patient self-report and urine TFV levels suggest that providers can trust patient reports of PrEP adherence behavior and support the use of adherence conversations in clinical settings, without the need for point of care biological monitoring. Findings also underscore the importance of continued attention to drivers of PrEP stops at the patient, clinic, and systems levels and the development of strategies that support sustained PrEP use.

Patient-centered practices for engaging transgender and gender diverse patients in clinical research studies

BACKGROUND

The purpose of this formative study was to assess barriers and facilitators to participation of transgender and gender diverse (TGD) patients in clinical research to solicit specific feedback on perceived acceptability and feasibility of research methods to inform creation of a multisite longitudinal cohort of primary care patients engaged in care at two community health centers.

METHOD

Between September-November 2018, four focus groups (FGs) were convened at two community health centers in Boston, MA and New York, NY (N = 28 participants across all 4 groups; 11 in Boston and 17 in New York). FG guides asked about patient outreach, acceptability of study methods and measures, and ideas for study retention. FGs were facilitated by TGD study staff, lasted approximately 90 min in duration, were audio recorded, and then transcribed verbatim by a professional transcription service. Thematic analyses were conducted by two independent analysts applying a constant comparison method. Consistency and consensus were achieved across code creation and application aided by Dedoose software.

RESULTS

Participants were a mean age of 33.9 years (SD 12.3; Range 18-66). Participants varied in gender identity with 4 (14.3%) men, 3 (10.7%) women, 8 (28.6%) transgender men, 10 (35.7%) transgender women, and 3 (10.7%) nonbinary. Eight (26.6%) were Latinx, 5 (17.9%) Black, 3 (10.7%) Asian, 3 (10.7%) another race, and 5 (17.9%) multiracial. Motivators and facilitators to participation were: research creating community, research led by TGD staff, compensation, research integrated into healthcare, research applicable to TGD and non-TGD people, and research helping TGD communities. Barriers were: being research/healthcare averse, not identifying as TGD, overlooking questioning individuals, research coming from a 'cisgender lens", distrust of how the research will be used, research not being accessible to TGD people, and research being exploitative.

CONCLUSION

Though similarities emerged between the perspectives of TGD people and research citing perspectives of other underserved populations, there are barriers and facilitators to research which are unique to TGD populations. It is important for TGD people to be involved as collaborators in all aspects of research that concerns them.

Chlamydia trachomatis Infection of the Neovagina in Transgender Women

We report 2 cases of neovaginal Chlamydia trachomatis infection in transgender women who underwent penile-inversion vaginoplasty procedures with integrated peritoneum and urethral grafts. These tissue types may have facilitated C. trachomatis infection. Medical providers should implement neovaginal screening for bacterial sexually transmitted infections in transgender patients at risk for infection.

Multiple species of noninteracting molecules adsorbed on a Bethe lattice

A simple method, previously used to calculate the equilibrium concentration of dimers adsorbed on a Bethe lattice as a function of the dimer activity, is generalized to solve the problem of a Bethe lattice in contact with a reservoir containing a mixture of molecules. The molecules may have arbitrary sizes and shapes consistent with the geometry of the lattice and the molecules do not interact with one another except for the hard-core restriction that two molecules cannot touch the same site. We obtain a set of simultaneous nonlinear equations, one equation for each species of molecule, which determines the equilibrium concentration of each type of molecule as a function of the (arbitrary) activities of the various species. Surprisingly, regardless of the number of species, the equilibrium concentrations are given explicitly in terms of the solution of a single equation in one unknown which can be solved numerically, if need be. Some numerical examples show that increasing the activity of one species need not necessarily decrease the equilibrium concentration of all other species. We also calculate the adsorption isotherm of an "annealed" Bethe lattice consisting of two types of sites which differently influence the activity of an adsorbed molecule. We prove that if the reservoir contains a finite number of molecular species, regions of two different polymer densities cannot simultaneously exist on the lattice. The widely used Guggenheim theory of mixtures, which can also be construed as a theory of adsorption, assumes for simplicity that the molecules in the mixture are composed of elementary units, which occupy sites of a lattice of coordination number q . Guggenheim's analysis relies on approximate combinatorial formulas which become exact on a Bethe lattice of the same coordination number, as we show in an appendix. Our analysis involves no combinatorics and relies only on recognizing the statistical independence of certain quantities. Despite the nominal equivalence of the two approaches, the easily visualized properties of the Bethe lattice enable one to solve some apparently difficult problems by quite elementary methods.

Order parameters and phase diagram of multiferroic RMn2O5

The generic magnetic phase diagram of multiferroic RMn2O5 (with R=Y, Ho, Tb, Er, Tm), which allows different sequences of ordered magnetic structures for different R's and different control parameters, is described using order parameters which explicitly incorporate the magnetic symmetry. A phenomenological magnetoelectric coupling is used to explain why some of these magnetic phases are also ferroelectric. Several new experiments, which can test this theory, are proposed.

Direct transition from a disordered to a multiferroic phase on a triangular lattice

We report the first direct transition from a paramagnetic and paraelectric phase to an incommensurate multiferroic in the triangular lattice antiferromagnet RbFe(MoO4)(2). Ferroelectricity is observed only when the magnetic structure has chirality and breaks inversion symmetry. A Landau expansion of symmetry-allowed terms in the free energy demonstrates that chiral magnetic order can give rise to a pseudoelectric field, whose temperature dependence agrees with experiment.

Dimer statistics on a Bethe lattice

We discuss the exact solutions of various models of the statistics of dimer coverings of a Bethe lattice. We reproduce the well-known exact result for noninteracting hard-core dimers by both a very simple geometrical argument and a general algebraic formulation for lattice statistical problems. The algebraic formulation enables us to discuss loop corrections for finite dimensional lattices. For the Bethe lattice we also obtain the exact solution when either (a) the dimers interact via a short-range interaction or (b) the underlying lattice is anisotropic. We give the exact solution for a special limit of dimers on a Bethe lattice in a quenched random potential in which we consider the maximal covering of dimers on random clusters at site occupation probability p. Surprisingly the partition function for "maximal coverage" on the Bethe lattice is identical to that for the statistics of branched polymers when the activity for a monomer unit is set equal to -p. Finally we give an exact solution for the number of residual vacancies when hard-core dimers are randomly deposited on a one dimensional lattice.

Spin waves in the frustrated kagomé lattice antiferromagnet KFe3(OH)6(SO4)2

The spin wave excitations of the S=5/2 kagomé lattice antiferromagnet KFe3(OH)6(SO4)2 have been measured using high-resolution inelastic neutron scattering. We directly observe a flat mode which corresponds to a lifted "zero energy mode," verifying a fundamental prediction for the kagomé lattice. A simple Heisenberg spin Hamiltonian provides an excellent fit to our spin wave data. The antisymmetric Dzyaloshinskii-Moriya interaction is the primary source of anisotropy and explains the low-temperature magnetization and spin structure.

1/d expansion for k-core percolation

The physics of k-core percolation pertains to those systems whose constituents require a minimum number of k connections to each other in order to participate in any clustering phenomenon. Examples of such a phenomenon range from orientational ordering in solid ortho-para H2 mixtures to the onset of rigidity in bar-joint networks to dynamical arrest in glass-forming liquids. Unlike ordinary (k = 1) and biconnected (k = 2) percolation, the mean field k > or = 3-core percolation transition is both continuous and discontinuous, i.e., there is a jump in the order parameter accompanied with a diverging length scale. To determine whether or not this hybrid transition survives in finite dimensions, we present a 1/d expansion for k-core percolation on the d-dimensional hypercubic lattice. We show that to order 1/d3 the singularity in the order parameter and in the susceptibility occur at the same value of the occupation probability. This result suggests that the unusual hybrid nature of the mean field k-core transition survives in high dimensions.

Magnetically driven ferroelectric order in Ni3V2O8

We show that long-range ferroelectric and incommensurate magnetic order appear simultaneously in a single phase transition in Ni3V2O8. The temperature and magnetic-field dependence of the spontaneous polarization show a strong coupling between magnetic and ferroelectric orders. We determine the magnetic symmetry using Landau theory for continuous phase transitions, which shows that the spin structure alone can break spatial inversion symmetry leading to ferroelectric order. This phenomenological theory explains our experimental observation that the spontaneous polarization is restricted to lie along the crystal b axis and predicts that the magnitude should be proportional to a magnetic order parameter.

Magnetic inversion symmetry breaking and ferroelectricity in TbMnO3

TbMnO3 is an orthorhombic insulator where incommensurate spin order for temperature T(N)<41 K is accompanied by ferroelectric order for T<28 K. To understand this, we establish the magnetic structure above and below the ferroelectric transition using neutron diffraction. In the paraelectric phase, the spin structure is incommensurate and longitudinally modulated. In the ferroelectric phase, however, there is a transverse incommensurate spiral. We show that the spiral breaks spatial inversion symmetry and can account for magnetoelectricity in TbMnO3.

Competing magnetic phases on a kagomé staircase

We present thermodynamic and neutron data on Ni3V2O8, a spin-1 system on a kagomé staircase. The extreme degeneracy of the kagomé antiferromagnet is lifted to produce two incommensurate phases at finite T--one amplitude modulated, the other helical--plus a commensurate canted antiferromagnet for T-->0. The H-T phase diagram is described by a model of competing first and second neighbor interactions with smaller anisotropic terms. Ni3V2O8 thus provides an elegant example of order from subleading interactions in a highly frustrated system.

Heart valve and arterial tissue engineering

In the industrialized world, cardiovascular disease alone is responsible for almost half of all deaths. Many of the conditions can be treated successfully with surgery, often using transplantation techniques; however, autologous vessels or human-donated organs are in short supply. Tissue engineering aims to create specific, matching grafts by growing cells on appropriate matrices, but there are many steps between the research laboratory and the operating theatre. Neo-tissues must be effective, durable, non-thrombogenic and non-immunogenic. Scaffolds should be bio-compatible, porous (to allow cell/cell communication) and amenable to surgery. In the early days of cardiovascular tissue engineering, autologous or allogenic cells were grown on inert matrices, but patency and thrombogenicity of grafts were disappointing. The current ethos is toward appropriate cell types grown in (most often) a polymeric matrix that degrades at a rate compatible with the cells' production of their own extracellular matrical proteins, thus gradually replacing the graft with a living counterpart. The geometry is crucial. Computer models have been made of valves, and these are used as three-dimensional patterns for mass-production of implant scaffolds. Vessel walls have integral connective tissue architecture, and application of physiological level mechanical forces conditions bio-engineered components to align in precise orientation. This article reviews the concepts involved and successes achieved to date.

Unusual symmetries in the Kugel-Khomskii Hamiltonian

The Kugel-Khomskii Hamiltonian for cubic titanates describes spin and orbital superexchange interactions between d(1) ions having threefold degenerate t(2g) orbitals. Since orbitals do not couple along "inactive" axes, perpendicular to the orbital planes, the total number of electrons in |alpha> orbitals in any such plane and the corresponding total spin are both conserved. A Mermin-Wagner construction shows that there is no long-range spin ordering at nonzero temperatures. Inclusion of spin-orbit coupling allows such ordering, but even then the excitation spectrum is gapless due to a continuous symmetry. Thus, the observed order and gap require more symmetry breaking terms.

Prolonged exercise induces angiogenesis and increases cerebral blood volume in primary motor cortex of the rat

Plastic changes in motor cortex capillary structure and function were examined in three separate experiments in adult rats following prolonged exercise. The first two experiments employed T-two-star (T(2)*)-weighted and flow-alternating inversion recovery (FAIR) functional magnetic resonance imaging to assess chronic changes in blood volume and flow as a result of exercise. The third experiment used an antibody against the CD61 integrin expressed on developing capillaries to determine if motor cortex capillaries undergo structural modifications. In experiment 1, T(2)*-weighted images of forelimb regions of motor cortex were obtained following 30 days of either repetitive activity on a running wheel or relative inactivity. The proton signal intensity was markedly reduced in the motor cortex of exercised animals compared with that of controls. This reduction was not attributable to alterations of vascular iron levels. These results are therefore most consistent with increased capillary perfusion or blood volume of forelimb regions of motor cortex. FAIR images acquired during experiment 2 under normocapnic and hypercapnic conditions indicated that resting cerebral blood flow was not altered under normal conditions but was elevated in response to high levels of CO(2), suggesting that prolonged exercise increases the size of a capillary reserve. Finally, the immunohistological data indicated that exercise induces robust growth of capillaries (angiogenesis) within 30 days from the onset of the exercise regimen. Analysis of other regions failed to find any changes in perfusion or capillary structure suggesting that this motor activity-induced plasticity may be specific to motor cortex.These data indicate that capillary growth occurs in motor areas of the cerebral cortex as a robust adaptation to prolonged motor activity. In addition to capillary growth, the vascular system also experiences heightened flow under conditions of activation. These changes are chronic and observable even in the anesthetized animal and are measurable using noninvasive techniques.

Rat pancreatic acinar cells express a cytosolic phospholipase D1b isoform that is not regulated by cholecystokinin

Evidence for the presence of a regulated phospholipase D (PLD) activity in pancreatic acinar cells is conflicting. Such knowledge is important because signal-activated PLD has been implicated in, amongst other things, regulated exocytosis. In this study, freshly isolated rat pancreatic acini were used to identify PLD transcripts by RT-PCR, to assess the presence and subcellular localization of PLD protein by Western blotting and to evaluate the presence of secretagogue-regulated PLD activity by means of the PLD-catalysed transphosphatidylation reaction. Transcripts of PLD1b and PLD2, but not PLD1a, were present in acinar cells. Moreover, a specific anti-human PLD1 antibody demonstrated the expression of substantial amounts of PLD1 protein. Intriguingly, however, the distribution pattern of acinar PLD1 seen following subcellular fractionation was clearly atypical in that immunoreactivity occurred predominantly in the acinar cytosol. Pretreatment of intact acini with a phorbol ester (4beta-phorbol 12-myristate 13-acetate, PMA) to activate PLD1 protein kinase C (PKC) dependently did not change the subcellular distribution of PLD1. Similarly, pretreatment of a broken cell preparation of acini with guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) to activate PLD via small GTPases and PMA also did not influence this distribution. In the presence of ethanol, cholecystokinin-(26-33)-peptide amide (CCK8) did not increase the amount of radiolabelled phosphatidylethanol (PtdEth) in intact acini prelabelled with either o-[32P]phosphate or [3H]myristic acid. Similarly, an increased cytosolic Ca2+ concentration evoked by the specific inhibitor of the endoplasmic reticulum Ca2+-ATPase, thapsigargin, did not stimulate acinar PLD activity whereas high-level PKC activation with PMA elicited slight stimulation. In contrast, all three stimuli are known to increase PLD activity readily in Chinese hamster ovary (CHO) cells expressing the rat pancreatic acinar cell CCKA receptor. Finally, the combination of PMA and GTPgammaS did not increase PLD activity following homologous reconstitution of acinar cytosol and membranes, whereas the same manoeuvre resulted in marked stimulation of PLD activity in CHO cells. Heterologous reconstitution experiments revealed that PLD activity in CHO membranes was stimulated readily in the presence of acinar cytosol, indicating that the acinar cytosol contains the necessary factors for PMA/GTPgammaS-induced stimulation of membrane PLD activity. In contrast, CHO cell cytosol did not confer PMA/GTPgammaS-stimulation of PLD activity on acinar membranes, in agreement with the predominantly cytosolic localization of acinar PLD. The present findings show that rat pancreatic acinar cells express a cytosolic PLD1 isoform that is not regulated by the physiologically important secretagogue CCK.

Two-stage rotational disordering of a molecular crystal surface: C60

We propose a two-stage mechanism for the rotational surface disordering phase transition of a molecular crystal, as realized in C60 fullerite. Our study, based on Monte Carlo simulations, uncovers the existence of a new intermediate regime, between a low-temperature ordered (2x2) state, and a high-temperature (1x1) disordered phase. In the intermediate regime there is partial disorder, strongest for a subset of particularly frustrated surface molecules. These concepts and calculations provide a coherent understanding of experimental observations, with possible extension to other molecular crystal surfaces.

Recurrent intracranial Masson's vegetant intravascular hemangioendothelioma. Case report and review of the literature

In the central nervous system, recurrence of intracranial Masson's vegetant intravascular hemangioendothelioma (MVIH) is rare. To the authors' knowledge, only three recurrent intracranial cases have been reported. The authors report the case of a 75-year-old woman with a recurrent left-sided cerebellopontine angle and middle cranial fossa MVIH. When the patient was 62 years of age, she underwent preoperative embolization and subtotal resection of the intracranial lesion followed by postoperative radiotherapy. She was well and free from disease until 9 years postoperatively when she became symptomatic. At 71 years of age, the patient again underwent preoperative embolization and near-gross-total resection of the lesion. Follow-up imaging performed 15 months later revealed tumor recurrence, and she underwent stereotactic gamma knife radiosurgery. At a 2.75-year follow-up review, the patient's imaging studies revealed stable residual tumor. This case report is unique in that it documents the clinical and pathological features, surgical and postoperative treatment, and long-term follow-up review of a patient with recurrent intracranial MVIH and suggests that this unusual vascular lesion is a slow-growing benign tumor rather than a reactive process. Because the pathological composition of the lesion may resemble an angiosarcoma, understanding this benign vascular neoplasm is crucial so that an erroneous diagnosis of malignancy is not made and unnecessary adjuvant therapy is not given.

Quantum theory of chiral interactions in cholesteric liquid crystals

The effective chiral interaction between molecules arising from long-range quantum interactions between fluctuating charge moments is analyzed in terms of a simple model of chiral molecules. This model is based on the approximations that (a) the dominant excited states of a molecule form a band whose width is small compared to the average energy of excitation above the ground state and (b) biaxial orientational correlation between adjacent molecules can be neglected. Previous treatments of quantum chiral interactions have been based on a multipole expansion of the effective interaction energy within second-order perturbation theory. We consider a system consisting of elongated molecules and, although we invoke the expansion in terms of coordinates transverse to the long axis of constituent molecules, we treat the longitudinal coordinate exactly. Such an approximation is plausible for molecules in real liquid crystals. The macroscopic cholesteric wave vector Q (Q=2 pi/P, where P is the pitch) is obtained via Q=h/K(2), where K2 is the Frank elastic constant for twist and h is the torque field which we calculate from the effective chiral interaction kappa(IJ)a(I)xa(J) x R(IJ), where the unit vector a(I) specifies the orientation of molecule I and R(IJ) is the displacement of molecule I relative to molecule J. We identify two distinct physical limits depending on whether one or both of the interacting molecules are excited in the virtual state. When both molecules are excited, we regain the R(-8)(IJ) dependence of kappa(IJ) on intermolecular separation found previously by Van der Meer et al. [J. Chem. Phys. 65, 3935 (1976)]. The two-molecule, unlike the one-molecule term, can be interpreted in terms of a superposition of pairwise interactions between individual atoms (or local chiral centers) on the two molecules. Contributions to kappa(IJ) when one molecule is excited in the virtual state are of order R(-7)(IJ) for helical molecules which are assumed not to have a global dipole moment, but whose atoms possess a dipole moment. It is shown that for a helical molecule Q can have either the same or the opposite sign as the chiral pitch of an individual molecule, depending on the details of the anisotropy of the atomic polarizability. The one-molecule mechanism can become important when the local atomic dipoles become sizable, although biaxial correlations (ignored here) should then be taken into account. Our results suggest how the architecture of molecular dipole moments might be adjusted to significantly influence the macroscopic pitch.

Surface enhanced Raman spectroscopic monitor of P. acnes lipid hydrolysis in vitro

Surface enhanced Raman spectroscopy (SERS) at a silver microelectrode was used to monitor bacterial hydrolysis of triglycerides in lipid mixtures that model sebaceous gland secretions. Mixtures of wax esters, squalene, triolein, and triisostearin were used as model skin secretions. The transformation was followed in vitro as changes in the SERS caused by hydrolysis of triglyceride to fatty acid. The fatty acid was adsorbed as its carboxylate, which is readily identified by the characteristic band at ca. 1395 cm(-1). Co-adsorption of propionate was also observed. The technique can also confirm the presence of bacteria by detection of short chain carboxylic acids released as products of fermentation during the growth of these cells.

Pediatric nutrition assessment: identifying children at risk

Nutrition services are important in the prevention of disabilities as well as in the treatment and/or habilitation of children with chronic illness. Level 1 nutrition care requires some basic knowledge of nutrition to screen for nutritional risk factors, knowledge of and access to referral systems for children identified to be at risk, and ability to use general nutrition education materials. Level 2 involves individualized nutrition assessment and intervention for problems such as anemia, chronic constipation, low- or high-calorie diets, feeding problems, and growth monitoring. Level 3 nutrition services are for children with identified disabilities such as cystic fibrosis, diabetes, and metabolic disorders that require specific complex nutrition interventions. The five major components of assessment of nutritional status in children are: anthropometric, clinical, biochemical, dietary, and feeding skill development.