A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067

Planets with radii between that of the Earth and Neptune (hereafter referred to as 'sub-Neptunes') are found in close-in orbits around more than half of all Sun-like stars1,2. However, their composition, formation and evolution remain poorly understood3. The study of multiplanetary systems offers an opportunity to investigate the outcomes of planet formation and evolution while controlling for initial conditions and environment. Those in resonance (with their orbital periods related by a ratio of small integers) are particularly valuable because they imply a system architecture practically unchanged since its birth. Here we present the observations of six transiting planets around the bright nearby star HD 110067. We find that the planets follow a chain of resonant orbits. A dynamical study of the innermost planet triplet allowed the prediction and later confirmation of the orbits of the rest of the planets in the system. The six planets are found to be sub-Neptunes with radii ranging from 1.94R⊕ to 2.85R⊕. Three of the planets have measured masses, yielding low bulk densities that suggest the presence of large hydrogen-dominated atmospheres.

Electronic Spin Qubit Candidates Arrayed within Layered Two-Dimensional Polymers

Molecular electronic spin qubits are promising candidates for quantum information science applications because they can be reliably produced and engineered via chemical design. Embedding electronic spin qubits within two-dimensional polymers (2DPs) offers the possibility to systematically engineer inter-qubit interactions while maintaining long coherence times, both of which are prerequisites to their technological utility. Here, we introduce electronic spin qubits into a diamagnetic 2DP by n-doping naphthalene diimide subunits with varying amounts of CoCp₂ and analyze their spin densities by quantitative electronic paramagnetic resonance spectroscopy. Low spin densities (e.g., 6.0 × 10¹² spins mm^-3) enable lengthy spin-lattice (T₁) and spin-spin relaxation (T₂) times across a range of temperatures, ranging from T₁ values of 164 ms at 10 K to 30.2 μs at 296 K and T₂ values of 2.36 μs at 10 K to 0.49 μs at 296 K for the lowest spin density sample examined. Higher spin densities and temperatures were both found to diminish T₁ times, which we attribute to detrimental cross-relaxation from spin-spin dipolar interactions and spin-phonon coupling, respectively. Higher spin densities decreased T₂ times and modulated the T₂ temperature dependence. We attribute these differences to the competition between hyperfine and dipolar interactions for electron spin decoherence, with the dominant interaction transitioning from the former to the latter as spin density and temperature increase. Overall, this investigation demonstrates that dispersing electronic spin qubits within layered 2DPs enables chemical control of their inter-qubit interactions and spin decoherence times.

Controlled n-Doping of Naphthalene-Diimide-Based 2D Polymers

2D polymers (2DPs) are promising as structurally well-defined, permanently porous, organic semiconductors. However, 2DPs are nearly always isolated as closed shell organic species with limited charge carriers, which leads to low bulk conductivities. Here, the bulk conductivity of two naphthalene diimide (NDI)-containing 2DP semiconductors is enhanced by controllably n-doping the NDI units using cobaltocene (CoCp₂ ). Optical and transient microwave spectroscopy reveal that both as-prepared NDI-containing 2DPs are semiconducting with sub-2 eV optical bandgaps and photoexcited charge-carrier lifetimes of tens of nanoseconds. Following reduction with CoCp₂ , both 2DPs largely retain their periodic structures and exhibit optical and electron-spin resonance spectroscopic features consistent with the presence of NDI-radical anions. While the native NDI-based 2DPs are electronically insulating, maximum bulk conductivities of >10^-4  S cm^-1 are achieved by substoichiometric levels of n-doping. Density functional theory calculations show that the strongest electronic couplings in these 2DPs exist in the out-of-plane (π-stacking) crystallographic directions, which indicates that cross-plane electronic transport through NDI stacks is primarily responsible for the observed electronic conductivity. Taken together, the controlled molecular doping is a useful approach to access structurally well-defined, paramagnetic, 2DP n-type semiconductors with measurable bulk electronic conductivities of interest for electronic or spintronic devices.

Tunable Cr4+ Molecular Color Centers

The inherent atomistic precision of synthetic chemistry enables bottom-up structural control over quantum bits, or qubits, for quantum technologies. Tuning paramagnetic molecular qubits that feature optical-spin initialization and readout is a crucial step toward designing bespoke qubits for applications in quantum sensing, networking, and computing. Here, we demonstrate that the electronic structure that enables optical-spin initialization and readout for S = 1, Cr(aryl)₄, where aryl = 2,4-dimethylphenyl (1), o-tolyl (2), and 2,3-dimethylphenyl (3), is readily translated into Cr(alkyl)₄ compounds, where alkyl = 2,2,2-triphenylethyl (4), (trimethylsilyl)methyl (5), and cyclohexyl (6). The small ground state zero field splitting values (<5 GHz) for 1-6 allowed for coherent spin manipulation at X-band microwave frequency, enabling temperature-, concentration-, and orientation-dependent investigations of the spin dynamics. Electronic absorption and emission spectroscopy confirmed the desired electronic structures for 4-6, which exhibit photoluminescence from 897 to 923 nm, while theoretical calculations elucidated the varied bonding interactions of the aryl and alkyl Cr⁴⁺ compounds. The combined experimental and theoretical comparison of Cr(aryl)₄ and Cr(alkyl)₄ systems illustrates the impact of the ligand field on both the ground state spin structure and excited state manifold, laying the groundwork for the design of structurally precise optically addressable molecular qubits.

Direct Aerobic Generation of a Ferric Hydroperoxo Intermediate Via a Preorganized Secondary Coordination Sphere

Enzymes exert control over the reactivity of metal centers with precise tuning of the secondary coordination sphere of active sites. One particularly elegant illustration of this principle is in the controlled delivery of proton and electron equivalents in order to activate abundant but kinetically inert oxidants such as O2 for oxidative chemistry. Chemists have drawn inspiration from biology in designing molecular systems where the secondary coordination sphere can shuttle protons or electrons to substrates. However, a biomimetic activation of O2 requires the transfer of both protons and electrons, and molecular systems where ancillary ligands are designed to provide both of these equivalents are comparatively rare. Here, we report the use of a dihydrazonopyrrole (DHP) ligand complexed to Fe to perform exactly such a biomimetic activation of O2. In the presence of O2, this complex directly generates a high spin Fe(III)-hydroperoxo intermediate which features a DHP• ligand radical via ligand-based transfer of an H atom. This system displays oxidative reactivity and ultimately releases hydrogen peroxide, providing insight on how secondary coordination sphere interactions influence the evolution of oxidizing intermediates in Fe-mediated aerobic oxidations.

A nearby transiting rocky exoplanet that is suitable for atmospheric investigation

Spectroscopy of transiting exoplanets can be used to investigate their atmospheric properties and habitability. Combining radial velocity (RV) and transit data provides additional information on exoplanet physical properties. We detect a transiting rocky planet with an orbital period of 1.467 days around the nearby red dwarf star Gliese 486. The planet Gliese 486 b is 2.81 Earth masses and 1.31 Earth radii, with uncertainties of 5%, as determined from RV data and photometric light curves. The host star is at a distance of ~8.1 parsecs, has a J-band magnitude of ~7.2, and is observable from both hemispheres of Earth. On the basis of these properties and the planet's short orbital period and high equilibrium temperature, we show that this terrestrial planet is suitable for emission and transit spectroscopy.

Synthetic investigation of competing magnetic interactions in 2D metal-chloranilate radical frameworks

The discovery of emergent materials lies at the intersection of chemistry and condensed matter physics. Synthetic chemistry offers a pathway to create materials with the desired physical and electronic structures that support fundamentally new properties. Metal–organic frameworks are a promising platform for bottom-up chemical design of new materials, owing to their inherent chemical predictability and tunability relative to traditional solid-state materials. Herein, we describe the synthesis and magnetic characterization of a new 2,5-dihydroxy-1,4-benzoquinone based material, (NMe₂H₂)_3.5Ga₂(C₆O₄Cl₂)₃ (1), which features radical-based electronic spins on the sites of a kagomé lattice, a geometric lattice known to engender exotic electronic properties. Vibrational and electronic spectroscopies, in combination with magnetic susceptibility measurements, revealed 1 exhibits mixed valency between the radical-bearing trianionic and diamagnetic tetraanionic oxidation states of the ligand. This unpaired electron density on the ligand forms a partially occupied kagomé lattice where approximately 85% of the lattice sites are occupied with an S = ½ spin. We found that gallium mediates ferromagnetic coupling between ligand spins, creating a ferromagnetic kagomé lattice. By modulation of the interlayer spacing via post-synthetic cation metathesis of 1 to (NMe₄)_3.5Ga₂(C₆O₄Cl₂)₃ (2) and (NEt₄)₂(NMe₄)_1.5Ga₂(C₆O₄Cl₂)₃ (3), we determined the nature of the magnetic coupling between neighboring planes is antiferromagnetic. Additionally, we determined the role of the metal in mediating this magnetic coupling by comparison of 2 with the In³⁺ analogue, (NMe₄)_3.5In₂(C₆O₄Cl₂)₃ (4), and we found that Ga³⁺ supports stronger superexchange coupling between ligand-based spins than In³⁺. The combination of intraplanar ferromagnetic coupling and interplanar antiferromagnetic coupling exchange interactions suggests these are promising materials to host topological phenomena.

2D metal–organic frameworks provide insight into kagomé spin physics.

New Ru(ii) complex for dual photochemotherapy: release of cathepsin K inhibitor and 1O2 production

A new complex, [Ru(tpy)(dppn)(Cbz-Leu-NHCH2CN)]2+ (1, tpy = 2,2':6',2''-terpyridine, dppn = benzo[i]dipyrido[3,2-a:2',3'-c]phenazine) was synthesized and its photochemical properties were investigated. This complex undergoes photorelease of the Cbz-Leu-NHCH2CN ligand, a known cathepsin K inhibitor, with a quantum yield, Φ450, of 0.0012(4) in water (λirr = 450 nm). In addition, 1 sensitizes the production of singlet oxygen upon visible light irradiation with quantum yield, ΦΔ, of 0.64(3) in CH3OH. The photophysical properties of 1 were compared with those of [Ru(tpy)(bpy)(Cbz-Leu-NHCH2CN)]2+ (2, bpy = 2,2'-bipyridine), [Ru(tpy)(dppn)(CH3CN)]2+ (3), and [Ru(tpy)(bpy)(CH3CN)]2+ (4) to evaluate the effect of the release of the Cbz-Leu-NHCH2CN inhibitor relative to the CH3CN ligand, as well as the role of dppn as the bidentate ligand for 1O2 production instead of bpy. Nanosecond transient absorption spectroscopy confirms the formation of the long-lived dppn-centered 3ππ* state in 1 and 3 with a maximum at ∼540 nm and τ ∼20 μs in deaerated acetonitrile. Complexes 1 and 3 are able to cause photoinduced damage to DNA (λirr ≥ 395 nm), whereas 2 and 4 do not photocleave DNA under similar experimental conditions. These results suggest that 1 is a promising agent for dual activity, both releasing a drug and producing singlet oxygen, and is poised to exhibit enhanced biological activity in phototochemotherapy upon irradiation with visible light.

Ketamine for rapid reduction of suicidal ideation: a randomized controlled trial

BACKGROUND

Suicide is a devastating public health problem and very few biological treatments have been found to be effective for quickly reducing the intensity of suicidal ideation (SI). We have previously shown that a single dose of ketamine, a glutamate N-methyl-d-aspartate (NMDA) receptor antagonist, is associated with a rapid reduction in depressive symptom severity and SI in patients with treatment-resistant depression.

METHOD

We conducted a randomized, controlled trial of ketamine in patients with mood and anxiety spectrum disorders who presented with clinically significant SI (n = 24). Patients received a single infusion of ketamine or midazolam (as an active placebo) in addition to standard of care. SI measured using the Beck Scale for Suicidal Ideation (BSI) 24 h post-treatment represented the primary outcome. Secondary outcomes included the Montgomery-Asberg Depression Rating Scale--Suicidal Ideation (MADRS-SI) score at 24 h and additional measures beyond the 24-h time-point.

RESULTS

The intervention was well tolerated and no dropouts occurred during the primary 7-day assessment period. BSI score was not different between the treatment groups at 24 h (p = 0.32); however, a significant difference emerged at 48 h (p = 0.047). MADRS-SI score was lower in the ketamine group compared to midazolam group at 24 h (p = 0.05). The treatment effect was no longer significant at the end of the 7-day assessment period.

CONCLUSIONS

The current findings provide initial support for the safety and tolerability of ketamine as an intervention for SI in patients who are at elevated risk for suicidal behavior. Larger, well-powered studies are warranted.

Electric-Field-Induced Reversible Phase Transitions in Two-Dimensional Colloidal Crystals

Two-dimensional colloidal crystals confined within electric field traps on the surface of a dielectrophoretic cell undergo reversible phase transitions that depend on the strength of the applied AC electric field. At low field strengths, the particles adopt a two-dimensional hexagonal close-packed lattice with p6m plane group symmetry and the maximum achievable packing fraction of φ = 0.91. Higher electric field strengths induce dipoles in the particles that provoke a phase transition to structures that depend on the number of particles confined in the trap. Whereas traps containing N = 24 particles transform to a square-packed lattice with p4m symmetry and φ = 0.79 is observed, traps of the same size containing N = 23 particles can also pack in a lattice with p2 symmetry and φ = 0.66. Traps with N = 21, 22, and 25 particles exhibit a mixture of packing structures, revealing the influence of lateral compressive forces, in addition to induced dipole interactions, in stabilizing loosely packed arrangements. These observations permit construction of a phase diagram based on adjustable parameters of electric field strength (0-750 V/cm) and particle number (N = 21-25).

Regulation of neural responses to emotion perception by ketamine in individuals with treatment-resistant major depressive disorder

The glutamate N-methyl-D-aspartate receptor antagonist ketamine has demonstrated antidepressant effects in individuals with treatment-resistant major depressive disorder (TRD) within 24 h of a single dose. The current study utilized functional magnetic resonance imaging (fMRI) and two separate emotion perception tasks to examine the neural effects of ketamine in patients with TRD. One task used happy and neutral facial expressions; the other used sad and neutral facial expressions. Twenty patients with TRD free of concomitant antidepressant medication underwent fMRI at baseline and 24 h following administration of a single intravenous dose of ketamine (0.5 mg kg(-1)). Adequate data were available for 18 patients for each task. Twenty age- and sex-matched healthy volunteers were scanned at one time point for baseline comparison. Whole-brain, voxel-wise analyses were conducted controlling for a family-wise error rate (FWE) of P<0.05. Compared with healthy volunteers, TRD patients showed reduced neural responses to positive faces within the right caudate. Following ketamine, neural responses to positive faces were selectively increased within a similar region of right caudate. Connectivity analyses showed that greater connectivity of the right caudate during positive emotion perception was associated with improvement in depression severity following ketamine. No main effect of group was observed for the sad faces task. Our results indicate that ketamine specifically enhances neural responses to positive emotion within the right caudate in depressed individuals in a pattern that appears to reverse baseline deficits and that connectivity of this region may be important for the antidepressant effects of ketamine.

Why do hospital mastectomy rates vary? Differences in the decision-making experiences of women with breast cancer

BACKGROUND

Hospital mastectomy rates vary. This study explores the relationship between mastectomy rates and breast cancer patients' consultation and decision-making experiences with specialist clinicians.

METHODS

Qualitative semi-structured interviews were conducted with 65 patients from three purposively selected breast units from a single UK region. Patients provided with a choice of breast cancer surgery (breast conservation therapy (BCT) or mastectomy) were purposively recruited from high, medium and low case-mix-adjusted mastectomy rate units.

RESULTS

Low mastectomy rate unit patients' consultation and decision-making experiences were markedly different to those of the medium and high mastectomy rate breast units. Treatment variation was associated with patients' perception of the most reassuring and least disruptive treatment; the content and style of information provision (equipoise or directed); level of patient participation in decision making; the time and process of decision making and patient autonomy in decision making. The provision of more comprehensive less directive information and greater autonomy, time and support of independent decision making were associated with a lower uptake of BCT.

CONCLUSION

Variation in hospital mastectomy rates was associated with differences in the consultation and decision-making experiences of breast cancer patients. Higher mastectomy rates were associated with the facilitation of more informed autonomous patient decision making.

Interaction between the Drosophila CAF-1 and ASF1 chromatin assembly factors

The assembly of newly synthesized DNA into chromatin is essential for normal growth, development, and differentiation. To gain a better understanding of the assembly of chromatin during DNA synthesis, we identified, cloned, and characterized the 180- and 105-kDa polypeptides of Drosophila chromatin assembly factor 1 (dCAF-1). The purified recombinant p180+p105+p55 dCAF-1 complex is active for DNA replication-coupled chromatin assembly. Furthermore, we have established that the putative 75-kDa polypeptide of dCAF-1 is a C-terminally truncated form of p105 that does not coexist in dCAF-1 complexes containing the p105 subunit. The analysis of native and recombinant dCAF-1 revealed an interaction between dCAF-1 and the Drosophila anti-silencing function 1 (dASF1) component of replication-coupling assembly factor (RCAF). The binding of dASF1 to dCAF-1 is mediated through the p105 subunit of dCAF-1. Consistent with the interaction between dCAF-1 p105 and dASF1 in vitro, we observed that dASF1 and dCAF-1 p105 colocalized in vivo in Drosophila polytene chromosomes. This interaction between dCAF-1 and dASF1 may be a key component of the functional synergy observed between RCAF and dCAF-1 during the assembly of newly synthesized DNA into chromatin.

Fetal death. A 10-year retrospective study

Fetal death has been defined by the World Health Organization as death before complete expulsion or extraction from its mother of a product of conception, irrespective of the duration of pregnancy. Certain causes of fetal death, including syphilis, Rh isoimmunization, toxemia, and diabetes, have shown significant declines over the past several decades. However, many fetal losses continue to occur from intrauterine infections, lethal malformations, fetal growth retardation, and abruptio placentae. Fetal death with no identifiable specific cause is another consideration when dealing with these cases. Other risk factors can include maternal, sociodemographic, and medical care factors. The authors reviewed all forensic cases referred for autopsy to the Forensic Section of the Medical University of South Carolina, Medical Examiners' Office over the 10-year period 1990-1999. All cases listed as fetal death or stillbirth were included. The 42 cases were analyzed as to fetus' gestational age, sex, race, weight, location of delivery, history of prenatal care, maternal drug use, chromosomal abnormalities, cause and manner of death, and autopsy findings. The black:white ratio was approximately 2:1, and the male:female ratio was virtually 1:1. Most fetuses were older than 20 weeks' gestational age, with one third between 20 and 29 weeks. The majority were externally normal aside from maceration. Only 7.5% had congenital anomalies. Twenty-one of 38 placentas were grossly and microscopically normal. Of cases with toxicologic analysis, 21% were positive for drugs, and 17% were positive for cocaine/benzoylecgonine. The manner of death was classified as natural (28), accident (2), and undetermined (12). Few studies have reported the specific causes of fetal death, and the lack of uniformity in data collection and classification of causes of fetal death has made comparisons difficult. The authors present this retrospective study to better determine the factors leading to fetal demise in the hope of assisting death investigators in this challenging arena.

An unusual case of anaphylaxis. Mold in pancake mix

Anaphylactic reactions involve contact with an antigen that evokes an immune reaction that is harmful. This type of reaction is a rapidly developing immunologic reaction termed a type I hypersensitivity reaction. The antigen complexes with an IgE antibody that is bound to mast cells and basophils in a previously sensitized individual. Upon re-exposure, vasoactive and spasmogenic substances are released that act on vessels and smooth muscle. The reaction can be local or systemic and may be fatal. The authors report the death of a 19-year-old white male who had a history of "multiple allergies," including pets, molds, and penicillin. One morning, he and his friends made pancakes with a packaged mix that had been opened and in the cabinet for approximately 2 years. The friends stopped eating the pancakes because they said that they tasted like "rubbing alcohol." The decedent continued to eat the pancakes and suddenly became short of breath. He was taken to a nearby clinic, where he became unresponsive and died. At autopsy, laryngeal edema and hyperinflated lungs with mucous plugging were identified. Microscopically, edema and numerous degranulating mast cells were identified in the larynx. The smaller airways contained mucus, and findings of chronic asthma were noted. Serum tryptase was elevated at 14.0 ng/ml. The pancake mix was analyzed and found to contain a total mold count of 700/g of mix as follows: Penicillium, Fusarium, Mucor, and Aspergillus. Witness statements indicate that the decedent ate two pancakes; thus he consumed an approximate mold count of 21,000. The decedent had a history of allergies to molds and penicillin, and thus was allergic to the molds in the pancake mix. The authors present this unusual case of anaphylaxis and a review of the literature.

Persistence of spermatozoa and prostatic acid phosphatase in specimens from deceased individuals during varied postmortem intervals

The survival of spermatozoa and the persistence of prostatic acid phosphatase has been an area of interest for investigators of sexual assault. However, not much documentation exists concerning the examination of a deceased individual with regard to the postmortem interval and presence of such evidence. The authors reviewed cases referred to the medical examiner's office during a 10-year period. During this time, 199 cases were both autopsied and examined for sexual assault. In particular, these examinations included procurement of swabs for Papanicolaou staining of smears and for quantitation of prostatic acid phosphatase. Most of the victims were female, although a few were male. In the majority of cases, the swabs for smears and prostatic acid phosphatase were taken from oral, vaginal, and anorectal areas in females and oral and anorectal areas in males. The smears all were stained with the routine Papanicolaou stain, and intact spermatozoa and spermatozoan heads were sought. The prostatic acid phosphatase was analyzed by the microparticle enzyme immunoassay method and reported as ng/ml. A level of greater than 100 ng/ml was considered positive. The cases were analyzed with respect to postmortem interval; presence or absence of intact spermatozoa or spermatozoan heads; presence of an elevated prostatic acid phosphatase; body location of the specimen; the time of year; location of the victim; and physical injury (anogenital) of sexual assault. The authors hope that by examining the laboratory evidence of sexual assault, a correlation can be drawn between the presence or absence of such evidence and the aforementioned variables.

Combined assessment of myocardial perfusion and regional left ventricular function by analysis of contrast-enhanced power modulation images

BACKGROUND

Echocardiographic contrast media have been used to assess myocardial perfusion and to enhance endocardial definition for improved assessment of left ventricular (LV) function. These methodologies, however, have been qualitative or have required extensive offline image analysis. Power modulation is a recently developed imaging technique that provides selective enhancement of microbubble-generated reflections. Our goal was to test the feasibility of using power modulation for combined quantitative assessment of myocardial perfusion and regional LV function in an animal model of acute ischemia.

METHODS AND RESULTS

Coronary balloon occlusions were performed in 18 anesthetized pigs. Transthoracic power modulation images (Agilent 5500) were obtained during continuous intravenous infusion of the contrast agent Definity (DuPont) at baseline and during brief coronary occlusion and reperfusion and were analyzed with custom software. At each phase, myocardial perfusion was assessed by calculation, in 6 myocardial regions of interest, of mean pixel intensity and the rate of contrast replenishment after high-power ultrasound impulses. LV function was assessed by calculation of regional fractional area change from semiautomatically detected endocardial borders. All ischemic episodes caused detectable and reversible changes in perfusion and function. Perfusion defects, validated with fluorescent microspheres, were visualized in real time and confirmed by a significant decrease in pixel intensity in the left anterior descending coronary artery territory after balloon inflation and reduced rate of contrast replenishment. Fractional area change decreased significantly in ischemic segments and was restored with reperfusion.

CONCLUSIONS

Power modulation allows simultaneous online assessment of myocardial perfusion and regional LV wall motion, which may improve the echocardiographic diagnosis of myocardial ischemia.

Tyrosine augments acute clozapine- but not haloperidol-induced dopamine release in the medial prefrontal cortex of the rat: an in vivo microdialysis study

Tyrosine availability can influence dopamine (DA) synthesis in highly electrophysiologically active DAergic neurons, such as those innervating the medial prefrontal cortex (MPFC). Whether tyrosine concentrations can also affect MPFC extracellular DA concentrations, measured in vivo, is not known. Since clozapine preferentially activates mesocortical DA neurons, we posited that tyrosine administration to a clozapine-pretreated rat would enhance the clozapine-induced augmentation of MPFC extracellular DA concentrations. Tyrosine alone (25-50mg/kg IP) did not affect mesocortical or striatal extracellular DA concentrations measured by in vivo microdialysis. Given 30 minutes after clozapine (10 mg/kg), tyrosine (50 mg/kg) significantly prolonged the clozapine-induced increase in MPFC extracellular DA concentrations but had no effect in the striatum. In contrast, tyrosine (50 mg/kg) significantly prolonged the haloperidol (1 mg/kg) induced increase in striatal extracellular DA concentrations but had no effect in the MPFC. These data constitute the first in vivo evidence that administration of tyrosine can selectively potentiate the clozapine-evoked increase in mesocortical extracellular DA concentrations.

Elderly suicide: a 10-year retrospective study

The suicide rate in the 65-year and older age group has been increasing since 1980. The elderly attempt suicide less often than younger people but are successful more often. The authors retrospectively reviewed all cases referred to the Forensic Pathology Section of the Medical Examiners' Office at the Medical University of South Carolina (Charleston, SC) from January 1988 through December 1997. The cases of suicide in victims 65 years and older totaled 78, accounting for 11.5% of all suicides reviewed. Of these 78 cases, 41% were autopsied and 59% were externally examined. All of the cases were initially analyzed as to age, race, sex, and method of suicide. Files also were reviewed to determine time of year of the suicide, toxicology results, psychiatric history, social history, medical history, and whether a suicide note was left. The ages of these suicide victims ranged from 65 to 94 years; men comprised 85% of the victims, and whites, 94%. The male-to-female and white-to-black ratios were 6:1 and 15: 1, respectively. The average age of the victim was 73 years. Gunshot wound was the most common method of suicide, accounting for 80.7% of the cases. Other methods included overdose (6.4%), hanging (3.8%), fall from height (2.6%), incised wounds (2.6%), drowning (2.6%), and carbon monoxide poisoning (1.3%).

Pediatric toxicologic deaths: a 10-year retrospective study

A 10-year retrospective study of pediatric toxicologic deaths was performed at the Medical University of South Carolina (Charleston, SC) from January 1989 to December 1998. During this time, 709 pediatric forensic autopsies were performed on children younger than 18 years of age. Eleven deaths were determined to be secondary to toxic exposures (excluding carbon monoxide poisonings secondary to fires). The remaining deaths were reviewed for the presence of alcohol or illicit drugs. The 11 toxicologic deaths were analyzed for age, sex, race, type of toxic exposure, cause and manner of death, location of incident, witness, and, in the younger age group, the primary caregiver at the time of exposure. The deaths had a bimodal age distribution (6 deaths in victims ages 15 to 17 and 5 deaths in victims ages 4 or younger), involving a wide range of toxins. The teenage group was composed of five males and one female, all white. The preschool group had three females and three males, all black. The manner of death ranged from accidental to suicidal to homicidal. In addition, in eight neonatal and fetal deaths, the victims tested positive for maternal cocaine use, and five of these victims tested positive for cocaine or benzoylecgonine. However, the cause of death was not stated to be cocaine in any of these neonatal and fetal cases.

Death by overlaying and wedging: a 15-year retrospective study

Overlaying, the accidental death by smothering caused by a larger individual sleeping on top of an infant, is a cause of death that has been documented for centuries. The hazard of death has been reported to be greater in infants less than 5 months of age but may occur in children up to the age of 2 years. When an adult or older child rolls on top of an infant, mechanical asphyxia results. The face may be pressed into the mattress or into the body of the sleeping adult or older child. The infant's air may be expressed, and he or she is unable to cry due to pressure on the thorax and the inability to inhale. Some pathologists and investigators believe that the victims of overlaying have no pertinent physical findings at autopsy and that any injury is indicative of inflicted trauma. Others believe that one may see contusions and abrasions from overlaying in and of itself. Wedging is another form of accidental mechanical asphyxia that may have negative autopsy findings. The prevalence of bruising, contusions, or facial and ocular petechiae is not clear. The author reviewed all pediatric forensic cases referred for autopsy to the Forensic Section of the Medical University of South Carolina/Medical Examiners' Office over the past 15 years, from 1985 to 1999. Of these, all cases of overlaying, cases listed as undetermined sudden infant death syndrome versus overlaying, and wedging were included. The cases were analyzed as to victims' age, sex, race, location/bedding, bed-sharer, and whether the bed-sharer was known to have ingested drugs or alcohol before sleep. Postmortem physical findings were also reviewed, particularly for documentation of contusions, abrasions, or facial or ocular petechiae. By clarifying not only the victim, bed-sharer, and scenario but also the presence or absence of physical findings in cases of overlaying, wedging, and other accidental asphyxia, we can better categorize these cases.

A rapid postmortem cardiac troponin T assay: laboratory evidence of sudden cardiac death

Postmortem examination may be useful in establishing the cause of sudden unexpected death. In many instances, however, limitations of staffing, budget, and time may force the pathologist to triage cases to external examination rather than autopsy. A rapid assay for cardiac troponin T (cTnT) to document suspected cardiac-related deaths may optimize the use of the time and resources of the autopsy pathologist. Peripheral blood was sampled percutaneously before each of 40 autopsies and placed in the well of the Cardiac T Rapid Assay unit in accordance with the included instructions, and the results were read after 15 minutes. The assay result, decedent age, postmortem interval, and evidence of cardiopulmonary resuscitation were tabulated and subsequently correlated with the cause of death. On final sign-out of each of the autopsies, the cause of death was determined to be cardiac-related (n = 20) versus the cause in non-cardiac control subjects (n = 20). This determination was made while the investigators were blinded to the cTnT assay result. Of the 20 cardiac deaths, 17 (85%) showed positive results for cTnT compared with 6 (30%) false-positive results among the 20 control cases; this result was statistically significant according to the chi-square test. In the over-50 age group, the sensitivity of this assay in detecting cardiac-related death was 91%, with a specificity of 86%. Perimortem cardiopulmonary resuscitation did not appear to result in false-positive results. In the appropriate setting, this rapid assay for cTnT can provide valuable data supportive of a cardiac-related death. This inexpensive test may best be used in triaging sudden deaths in persons over 50 to external examination versus complete autopsy.

Accuracy of echocardiographic estimates of left ventricular mass in mice

Genetically modified mice have created the need for accurate noninvasive left ventricular mass (LVM) measurements. Recent technical advances provide two-dimensional images adequate for LVM calculation using the area-length method, which in humans is more accurate than M-mode methods. We compared the standard M-mode and area-length methods in mice over a wide range of LV sizes and weights (62-210 mg). Ninety-one CD-1 mice (38 normal, 44 aortic banded, and 9 inherited dilated cardiomyopathy) were imaged transthoracically (15 MHz linear transducer, 120 Hz). Compared with necropsy weights, area-length measurements showed higher correlation than the M-mode method (r = 0.92 vs. 0.81), increased accuracy (bias +/- SD: 1.4 +/- 27.1% vs. 36.7 +/- 51.6%), and improved reproducibility. There was no significant difference between end-systolic and end-diastolic estimates. The truncated ellipsoid estimation produced results similar in accuracy to the area-length method. Whereas current echocardiographic technology can accurately and reproducibly estimate LVM with the two-dimensional, area-length formula in a variety of mouse models, additional technological improvements, rather than refinement of geometric models, will likely improve the accuracy of this methodology.

Detection of regional temporal abnormalities in left ventricular function during acute myocardial ischemia

Echocardiographic diagnosis of myocardial ischemia is based on visualizing hypokinesis, which occurs late in the ischemic cascade. We hypothesized that temporal changes in endocardial motion may constitute sensitive early markers of ischemia. Two protocols were performed in 19 anesthetized pigs. Protocol 1 included 54 intracoronary balloon occlusions. Transthoracic images were acquired at baseline and every 15 s during 5 min of occlusion and reperfusion. In protocol 2, ischemia was induced in 12 animals by use of graded dobutamine infusion, after creating significant partial occlusions without a resting wall motion abnormality. Systolic and diastolic endocardial motion was color encoded using color kinesis and analyzed using custom software. All ischemic episodes caused detectable and reversible changes. The earliest sign of ischemia was tardokinesis in 31/54 occlusions, whereas hypokinesis appeared first in 23/54 cases. Dobutamine-induced ischemia caused tardokinesis first in 9/12 and hypokinesis in 3/12 animals. Reversible ischemic changes in regional left ventricular performance can be objectively detected using analysis of echocardiographic images and will likely improve the early noninvasive diagnosis of acute ischemia.

Suicide: a ten-year retrospective study

Suicide is a complex phenomenon associated with psychological, biological, and social factors, claiming approximately 30,000 lives each year in the United States. We retrospectively reviewed all cases referred to the Medical Examiners' Office/Forensic Pathology Section at the Medical University of South Carolina from January 1988 to December 1997. The cases of suicide totaled 678. All of the cases were analyzed as to age/race/sex, method of suicide, time of year, and toxicological results. Files were also reviewed to determine if the victim left behind a suicide note. The ages ranged from 12 to 94 years; males comprised 79.5% of the victims, and whites 78.3%. The male to female and white to black ratios were both 3.9:1. The most common methods were gunshot wounds, accounting for 64.6% of the cases. No correlation existed with time of year, and the number of cases was not increased around major holidays. The group of victims 65 years and older and the pediatric group under the age of 18 were also examined separately.

Isolation and identification of male and female DNA on a postcoital condom

BACKGROUND

Identification of male perpetrators of sexual assault may be made from cells and fluids recovered from postcoital condoms. To date, the focus has been on identifying the person who had worn the condom.

OBJECTIVE

To describe a method for scientifically identifying both the male and female participants in a sex act by employing polymerase chain reaction-based technology on swabs taken from the internal and external surfaces of a condom. Fluorescence in situ hybridization may be used to screen for the presence of female cells on a condom.

METHODS

Swabs were taken from the internal and external surfaces of a condom 8 hours postcoitus. DNA was isolated from each swab through standard organic extraction. Extracted DNA was amplified for 8 different genetic loci using the Promega PowerPlex kit and the sex identification amelogenin marker. Amplified samples were electrophoresed on precast sequencing gels and analyzed fluorescently using a Hitachi FMBIO 2 fluorescent scanner and software. Each DNA sample obtained from the condom was compared with male and female buccal controls. At the time of collection, air-dried slides were prepared from the swabs for subsequent multicolor fluorescence in situ hybridization using dual X- and Y-chromosome probes with 4'-6-diamidino-2-phenylindole (DAPI) counterstaining.

RESULTS

A pure sample of female DNA was isolated from the external surface of the condom as determined by exclusive amplification of the X-chromosome-specific 212-base pair amelogenin marker. Swabs taken from the internal surface yielded DNA originating from the male participant. Identification was conclusive at 8 of 8 genetic loci. Fluorescence in situ hybridization identified pure populations of male epithelial cells from the internal surface of the condom and female cells from the external surface.

CONCLUSIONS

Cells shed from a female during sexual intercourse can be retrieved from the external surface of a condom following sexual intercourse. Fluorescence in situ hybridization can be used to screen for the presence of female cells, and positive identification of the female sexual partner can then be made using polymerase chain reaction-based methods. We suggest that swabs taken from both surfaces of a condom used during sexual assault may be used to provide information that will definitively link the victim to the suspect.

Identification of female cells in postcoital penile swabs using fluorescence in situ hybridization

Traditionally, the finding of semen, that is, spermatozoa and acid phosphatase, in cervicovaginal specimens has been considered the laboratory evidence needed to prove recent sexual contact. Recent research with fluorescence in situ hybridization (FISH) has shown that in the absence of semen, male epithelial and inflammatory cells can be found within the female genital tract. A striking paucity of literature exists pertaining to the examination of the penis of an alleged assailant for potential evidence indicative of sexual assault. The current study uses FISH to analyzepostcoital swabs of the penis for such laboratory evidence. A male and female volunteer couple consented to participate in this study. Following coitus, the male partner presented to one of the investigators for penile swabbing. Swabs were taken at varying postcoital intervals (1-24 hours) subsequent to 10 coital episodes. The male participant was instructed not to shower following coitus, but to otherwise go about daily activities until specimen collection. To obtain each sample, 4 sterile cotton-tipped applicators were slightly moistened in sterile saline and swabbed along the length of the penile shaft and around the base of the penis. From the swabs, 3 air-dried slides were prepared, coded, and blinded. As controls, swabs were taken from the buccal surfaces of both volunteers. Multicolor FISH was performed using dual X- and Y-chromosome probes, and slides were counterstained with 4'-6-diamidino-2-phenylindole (DAPI). Cells were easily visualized under a fluorescent microscope, but only cells with 2 nonoverlapping fluorescent signals were counted. Fluorescence in situ hybridization is highly sensitive and specific, and the dual probes easily distinguished between male and female cells. Female cells were identified on smears from every penile swab over the entire 1- to 24-hour postcoital interval. The FISH technique, previously successful in identifying male cells within the female genital tract, may also be employed on penile swabs. Once the presence of female cells is confirmed by FISH, the identity of the female can be confirmed by DNA analysis. Potentially, with such current molecular analyses, both the assailant and the victim can be positively identified.

Isolation and identification of female DNA on postcoital penile swabs

After sexual assault, cells originating from the assailant may be recovered from the victim. Through polymerase chain reaction (PCR)-based technology, positive scientific identification of the assailant may be made from these cells. Described is a prospective study describing a method for positively identifying cells from a female sex partner obtained from postcoital swabs of the penis of the male sex partner. Swabs were taken from the penis of a man at 1- to 24-hour intervals after coitus. DNA was isolated from each swab through standard organic extraction methods. The presence of female DNA was detected using the gender-specific amelogenin marker. Extracted DNA was amplified for eight different genetic loci using the Promega PowerPlex kit (Promega) and Amplitaq Gold (Perkin Elmer). Amplified samples were electrophoresed on precast sequencing gels (Hitachi) and were analyzed fluorescently using Hitachi's FMBIO 2 fluorescent scanner and software. Each sample obtained from a penile swab or condom was compared to male and female buccal controls. Female DNA was isolated from all postcoital penile swabs as determined by exclusive amplification of the X-chromosome specific 212 base pair amelogenin marker. In all cases, scientific identification of the female DNA from the swabs was determined by coamplification of eight STR loci (PowerPlex) and was compared to female and male control profiles. Cells shed from a female victim during sexual intercourse can be retrieved from the penis of a male offender after sexual intercourse during a 1- to 24-hour postcoital interval. DNA can be extracted from these cells and can be used to scientifically identify the female sexual participant through PCR-based technology. It is suggested that penile swabs be taken from alleged perpetrators of sexual assaults to associate them with a female victim.

Phenotypic manifestation in a child with 46,X,der(X)t(X;1)(q24;q31.1)

We report on a 5-year-old girl with multiple congenital anomalies, developmental delay, and a de novo unbalanced translocation between chromosomes X and 1[46,X,der(X)-t(X;1)(q24;q31.1)] resulting in partial trisomy 1q and partial monosomy Xq. The karyotype shows inactivation of the abnormal X chromosome. The translocated portion of 1q remains active in the tissues studied. This is the third case report with partial trisomy 1q and partial monosomy Xq. However, it is the first with specific breakpoints at 1q31.1 and Xq24.

Formation of charge-transfer complexes from neutral bis(porphyrin) sandwiches

Lanthanide(III) bis(porphyrin) sandwich complexes of octaethyltetraazaporphyrin (OETAP) were synthesized and characterized by UV-vis, IR, and NMR spectroscopies. Cyclic voltammetry results indicate that these neutral sandwich complexes are very easily reduced. Charge-transfer reactions were performed in solution with Ln-(OETAP)2 sandwiches and zirconium(IV) bis(porphyrin) sandwiches. The lanthanide sandwiches partially oxidize the zirconium sandwiches in solution, and a solvent dependence of the charge-transfer reaction was observed. The solid-state properties of these charge-transfer materials were also studied. Magnetic susceptibility results suggest weak intermolecular interactions between the sandwiches. The conductivities of the charge-transfer species are greatly improved relative to those of the insulating undoped sandwiches, but the conductivities are in the lower semiconducting region. The low conductivity values are thought to be due to poor intermolecular overlap.

Vascular assessment

The assessment of the patient with peripheral vascular disease encompasses a thorough history and physical examination with the adjunctive use of the noninvasive vascular laboratory to confirm, localize, and grade lesions. The need for additional vascular testing depends upon the clinical scenario and urgency with which intervention must be undertaken with contrast angiography reserved for planning surgical intervention. While multiple noninvasive and invasive methods are available to assess the peripheral vasculature, it should be obvious that not every patient requires an exhaustive battery of tests in order to evaluate their vascular status. In general, only those tests that are likely to provide information which will alter the course of action should be performed. Differing clinical syndromes mandate the extent of peripheral vascular testing. Table 5 lists distinct clinical syndromes and presentations and the peripheral vascular testing that is likely to yield timely and cost efficient results.

A decade of pediatric homicide: a retrospective study at the Medical University of South Carolina

More than 3 million children are abused and/or neglected each year in the United States. Unfortunately, a significant percentage of these cases result in homicide by child abuse or child neglect. Causes of death range from blunt force trauma and shaking to asphyxia to immolation. We retrospectively reviewed all pediatric forensic cases referred to the Medical University of South Carolina Forensic Pathology Section over the past 10 years, from January 1986 to December 1995. Of these, we looked only at children < or =5 years of age. The majority (342 cases, 69%) of these deaths were classified as natural, 96 (19%) as accident, and 60 (12%) as homicide. Of the homicides, we examined the cause of death; age, gender, and race of the victim; relationship to the perpetrator; time interval between injury and death; and the initial history given as to the cause of the injury. The cause of death fell into nine categories, the number one category being head trauma. Forty-five percent of the homicides were by head trauma, 12% by abdominal or body trauma, 25% by asphyxia (with half of these due to drowning), 10% by carbon monoxide poisoning or thermal injury, and the remaining 8% involving cases of neglect, stabbing, and poisoning. The majority of the homicide victims were male (67%) and black (67%). Forty-six percent were < or =1 year of age. Approximately 25% of the homicide cases were designated as shaken baby syndrome (SBS). In 97% of the cases, the assailant was known to the victim and was a family relative in 77%. Sixty-three percent of the assailants were female and 45% of the assailants were male; in 12%, the assailants were both parents, and in 1 case, the assailant remains unknown. Of the asphyxia deaths, 87% of the assailants were female. The time interval between injury and death ranged from minutes to hours in most cases to months in cases of repeated abuse and chronic injury and sequelae. The time interval between injury and the onset of symptoms remains unknown in most cases due to inconsistencies in the history and lack of credibility of the caretaker. The most common initial history given was "a fall" (20%). We report our findings of a decade of pediatric homicides to increase awareness of the common scenarios and case histories, demographics of the victims, causes of death, and perpetrators of pediatric homicide.

Suicide under the age of eighteen: a 10-year retrospective study

The number of suicides in the pediatric age group is rising, and death investigators need to be aware of the common scenarios, risk factors, and victims as they investigate such cases to properly assign the cause and manner of death. We reviewed all pediatric cases referred to the Medical University of South Carolina, Forensic Section, from January 1988 through January 1998. Thirty-one cases of pediatric suicide were analyzed with regards to age, gender, race, cause of death, surrounding circumstances, and past history. Sixty-eight percent of victims were aged 16 or 17 years, 84% were male, 68% were white, 78% used firearms to commit suicide, 81% were found within close vicinity of their home, and 26% had a documented history of mental illness. Suicide is a manner of death that is often difficult for the public to accept, especially in pediatric cases. We report our findings in this 10-year retrospective study to better understand this entity and work toward the prevention of future cases.

Speedballing with needle embolization: case study and review of the literature

Foreign-body embolization is not an uncommon occurrence. However, to our knowledge, there are only ten reported cases of needle embolization associated with intravenous drug use. We report the sudden death of a 49-year-old white male with a known history of crack cocaine abuse. At autopsy, suspicious needle marks were noted on the right lower extremity. The lungs were of increased weight at 1000 and 1090 g and appeared edematous. The heart weighed 520 g and had a normal red-brown myocardium. Upon sectioning, a broken hypodermic needle of very small caliber was identified in the right ventricular myocardium protruding into the right ventricular chamber. This needle apparently traveled from the injection site to the right ventricle. The right ventricle was dilated and hypertrophied, and microscopic examination showed hyperemic myocardium surrounding the needle. Sections of lung showed numerous foreign-body type giant cells containing polarizable foreign material consistent with intravenous drug use. Toxicological analysis revealed the presence of ethanol (36 mg/dL), cocaine (0.098 mg/L), benzoylecgonine (2.16 mg/L), and morphine (0.841 mg/L). Urine and blood were positive for the presence of 6-monoacetylmorphine. Based on the toxicological analysis, the cause of death was determined to be cocaine and heroin toxicity, and the manner accidental. The needle embolus was considered an incidental finding.

Cost effectiveness of community leg ulcer clinics: randomised controlled trial

OBJECTIVES

To establish the relative cost effectiveness of community leg ulcer clinics that use four layer compression bandaging versus usual care provided by district nurses.

DESIGN

Randomised controlled trial with 1 year of follow up.

SETTING

Eight community based research clinics in four trusts in Trent.

SUBJECTS

233 patients with venous leg ulcers allocated at random to intervention (120) or control (113) group.

INTERVENTIONS

Weekly treatment with four layer bandaging in a leg ulcer clinic (clinic group) or usual care at home by the district nursing service (control group).

MAIN OUTCOME MEASURES

Time to complete ulcer healing, patient health status, and recurrence of ulcers. Satisfaction with care, use of services, and personal costs were also monitored.

RESULTS

The ulcers of patients in the clinic group tended to heal sooner than those in the control group over the whole 12 month follow up (log rank P=0.03). At 12 weeks, 34% of patients in the clinic group were healed compared with 24% in the control. The crude initial healing rate of ulcers in intervention compared with control patients was 1.45 (95% confidence interval 1.04 to 2. 03). No significant differences were found between the groups in health status. Mean total NHS costs were 878.06 pounds per year for the clinic group and 859.34 pounds for the control (P=0.89).

CONCLUSIONS

Community based leg ulcer clinics with trained nurses using four layer bandaging is more effective than traditional home based treatment. This benefit is achieved at a small additional cost and could be delivered at reduced cost if certain service configurations were used.

Sudden unexpected death resulting from an anomalous hypoplastic left coronary artery

We present a case of sudden death in a 24-year-old, healthy white female who was physically active and participated in sports, including soccer. Two weeks prior to her death, an insurance physical examination revealed an abnormal electrocardiogram which demonstrated flipped T waves in the anterior leads. There was no other remarkable medical history. At autopsy, only one coronary ostium was demonstrated and it originated from the right aortic sinus. Approximately 0.8 cm from this right coronary artery (RCA) ostium, a left coronary artery (LCA) branched off the RCA at a 90-degree angle. The LCA had luminal diameter of 0.4 m but the LCA had a luminal diameter of only 0.1 cm. The LCA coursed anterior to the base of the pulmonary artery and down the anterior ventricular septum reflecting the usual course of the left anterior descending (LAD) coronary artery. The LCA and RCA paths appeared to merge or terminate at the anterior left ventricular myocardium which was discolored gray, a process that involved the inner and middle thirds of the myocardium. Based on the autopsy findings, we certified the cause of death as a probable arrhythmia due to myocardial fibrosis and dystrophic calcification resulting from complications of an anomalous hypoplastic left coronary artery. Anomalies of coronary arteries have been classified and studied at autopsy and by clinical angiography. Coronary artery anomalies can be divided into minor and major forms with major anomalies often resulting in cardiac dysfunction that may cause failure and death. Minor anomalies, in general, have no pathophysiological significance and are compatible with life. Minor anomalies include variations in number and location of coronary ostia. A single coronary ostia is exceedingly rare in hearts with no other congenital malformations. The prognostic significance can be unpredictable. A single coronary artery has the potential to be dangerous if obstructed at its main stem, or if it branches at an acute angle. Additionally, hypoplasia of one or more coronary arteries has been found to be associated with sudden death.

Pretreatment with pertussis toxin differentially modulates morphine- and beta-endorphin-induced antinociception in the mouse

The experiments were designed to determine the role of pertussis toxin-(PTX) sensitive G-proteins Gi/Go in the brain and spinal cord in antinociception induced by epsilon-opioid receptor agonist beta-endorphin (beta-EP) and mu-opioid receptor agonist morphine. The effects of intracerebroventricular (i.c.v.) or intrathecal (i.t.) pretreatment with PTX on antinociception induced by morphine, beta-endorphin (beta-EP) and other selective opioid receptor agonists given i.c.v. or i.t. were studied in male ICR mice. Antinociception was assessed by the tail-flick and hot-plate tests. An i.c.v. pretreatment with PTX (0.5 microgram) caused a time- and dose-dependent attenuation of the tail-flick and hot-plate inhibition induced by i.c.v.-challenged morphine-induced antinociception. However, the same pretreatment with PTX did not affect the antinociception induced by i.c.v.-administered beta-EP. The tail-flick and hot-plate inhibition induced by selective mu-, delta- and kappa-opioid receptor agonist, DAMGO, [D-Ala2]deltorphin II and U50,488H, respectively, given i.c.v. was also attenuated by the i.c.v. pretreatment with PTX. An i.t. pretreatment with PTX (0.5 microgram) blocked markedly the tail-flick inhibition induced by morphine and beta-EP given i.c.v. However, the same treatment did not affect the hot-plate inhibition induced by beta-EP and attenuated, to a lesser degree, the hot-plate inhibition induced by morphine given i.c.v. An i.t. pretreatment with PTX blocked the tail-flick inhibition induced by selective delta 2-, alpha 2 and 5-HT receptor agonist [D-Ala2]deltorphin, norepinephrine and 5-HT, respectively, given i.t. Our results indicate that the antinociception induced by mu-, delta-, kappa-opioid receptor agonists given supraspinally is mediated by respectively opioid receptors that are coupled to PTX-sensitive Gi/Go proteins at the supraspinal sites and subsequently mediated by the activation of PTX-sensitive Gi/Go coupled receptors in the spinal cord. However, the antinociception induced by beta-EP given supraspinally is mediated by the PTX-resistant epsilon-opioid receptors at the supraspinal sites and subsequently activation of the delta 2-opioid receptors in the spinal cord that is sensitive to the pretreatment with PTX.

Mouse model of hyperkinesis implicates SNAP-25 in behavioral regulation

Although hyperkinesis is expressed in several neurological disorders, the biological basis of this phenotype is unknown. The mouse mutant coloboma (Cml+) exhibits profound spontaneous locomotor hyperactivity resulting from a deletion mutation. This deletion encompasses several genes including Snap, which encodes SNAP-25, a nerve terminal protein involved in neurotransmitter release. Administration of amphetamine, a drug that acts presynaptically, markedly reduced the locomotor activity in coloboma mice but increased the activity of control mice implicating presynaptic function in the behavioral abnormality. In contrast, the psychostimulant methylphenidate increased locomotor activity in both coloboma and control mice. When a transgene encoding SNAP-25 was bred into the coloboma strain to complement the Snap deletion, the hyperactivity expressed by these mice was rescued, returning these corrected mice to normal levels of locomotor activity. These results demonstrate that the hyperactivity exhibited by these mice is the result of abnormalities in presynaptic function specifically attributable to deficits in SNAP-25 expression.

Fine needle aspiration biopsy of hepatic lymphomas: cytomorphology and ancillary studies

OBJECTIVE

The utility of fine needle aspiration biopsy (FNAB) for the diagnosis of epithelial hepatic neoplasms is now widely recognized. The liver may also play host to malignant nonepithelial stromal and lymphoreticular neoplasms, both metastatic and rarely primary. The cytomorphology of these hepatic tumors in aspiration smears is much less well known. In the current study, we examined FNAB material from hepatic lymphomas, including ancillary studies.

STUDY DESIGN

We collected 16 cases of lymphoma involving the liver and diagnosed by FNAB. The patients included seven women and nine men, with ages ranging from 34 to 84 years. Nine patients did not have a diagnosis of lymphoma prior to FNAB. In all cases, aspiration smears were stained by both Diff-Quik and Papanicolaou stain.

RESULTS

Dispersed, monomorphic lymphoid cells were usually numerous, whereas benign hepatocytes were scanty. In addition to the lymphoid appearances of individual cells, helpful clues included the presence of lymphoglandular bodies and the absence of true intercellular cohesion. There were 6 large cell, 3 immunoblastic, 2 small cell, 1 small cell cleaved, 2 mixed cell and 2 unclassified lymphomas in our FNAB series. Immunocytochemical studies were performed on 9 aspirated specimens, flow cytometry on 4 and gene rearrangement on 1. All these ancillary studies supported the cytomorphologic diagnosis of lymphoma, with approximately 90% classified as of B-cell lineage. All seven subsequent histologic examinations were confirmatory.

CONCLUSION

Other entities that must be considered in the FNAB differential diagnosis of hepatic lesions are nonlymphoreticular small cell neoplasms, inflammatory processes and sinusoidal hematopoietic cells. FNAB with ancillary studies can successfully establish the diagnosis of involvement of the liver by lymphoma.

Dyadic deaths involving Huntington's disease: a case report

Huntington's disease is a hereditary neurodegenerative disorder characterized by involuntary choreiform movements and progressive dementia. Although controversy exists regarding the exact risk of suicide in patients with Huntington's chorea, the literature supports an increased risk of suicide, especially in the early stages of this disease. We describe a case of homicide-suicide involving a father and son. The 60-year-old father, the homicide victim, suffered from advanced Huntington's disease; his 30-year-old son, the assailant, had a history of depression but had not been diagnosed with Huntington's disease at the time of his suicide. The psychiatric implications of this dementing disease, including the risk of suicide, are discussed. The gross, histologic, and molecular genetic features of this neurodegenerative disease are also described. The recognition of this autosomal dominantly inherited disorder at autopsy can make a profound impact on the lives of surviving family members.