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Biomedical subjects

M Germain

Publications and source records attributed to M Germain.

At least 37 records · Page 2Linked to original sources
PubMed2003

The risks and benefits of accepting men who have had sex with men as blood donors.

BACKGROUND: It has been suggested that men who have had sex with men (MSM) should become eligible to donate blood if they recently abstained from male-to-male sex. STUDY DESIGN AND METHODS: The impact of a 12-month deferral policy for MSM on the risk of introducing contaminated units in the blood supply and the benefit of obtaining additional donations were estimated. Considered were the prevalence of HIV among MSM, the window period of infection, the rate of laboratory testing errors, and the occurrence of other system failures. This was compared with the risk and benefit that currently results from accepting female donors who have had sex with MSM. RESULTS: The revised policy for MSM would potentially result in one HIV-contaminated unit for every 136,000 additional donations (95% CI, 1 in 69,000 to 1 in 268,000), for an overall increase in HIV risk estimated at 8 percent. The number of donations would increase by 1.3 percent (95% CI, 0.9%-1.7%). The risk-benefit ratio of currently accepting female partners of MSM is approximately five times lower. CONCLUSION: The risk increment of accepting 12-month abstinent MSM would be very small but not zero. From a risk-benefit perspective, the current deferral policy for MSM is more efficient compared to an analogous hypothetical criterion for female partners of MSM.

Blood Donors↗
PubMed2002

Coherent rho(0) production in ultraperipheral heavy-ion collisions.

The STAR Collaboration reports the first observation of exclusive rho(0) photoproduction, AuAu-->AuAurho(0), and rho(0) production accompanied by mutual nuclear Coulomb excitation, AuAu-->Au*Au*rho(0), in ultraperipheral heavy-ion collisions. The rho(0) have low transverse momenta, consistent with coherent coupling to both nuclei. The cross sections at sqrt[s(NN)]=130 GeV agree with theoretical predictions treating rho(0) production and Coulomb excitation as independent processes.

Journal Article↗
PubMed2002

Centrality dependence of high-p(T) hadron suppression in Au+Au collisions at sqrt[s(NN)]=130 GeV.

Inclusive transverse momentum distributions of charged hadrons within 0.2<p(T)<6.0 GeV/c have been measured over a broad range of centrality for Au+Au collisions at sqrt[s(NN)]=130 GeV. Hadron yields are suppressed at high p(T) in central collisions relative to peripheral collisions and to a nucleon-nucleon reference scaled for collision geometry. Peripheral collisions are not suppressed relative to the nucleon-nucleon reference. The suppression varies continuously at intermediate centralities. The results indicate significant nuclear medium effects on high-p(T) hadron production in heavy-ion collisions at high energy.

Journal Article↗
PubMed2002

Azimuthal anisotropy of K(0)(S) and Lambda+Lambda production at midrapidity from Au+Au collisions at sqrt[s(NN)]=130 GeV.

We report STAR results on the azimuthal anisotropy parameter v(2) for strange particles K(0)(S), Lambda, and Lambda at midrapidity in Au+Au collisions at sqrt[s(NN)]=130 GeV at the Relativistic Heavy Ion Collider. The value of v(2) as a function of transverse momentum, p(t), of the produced particle and collision centrality is presented for both particles up to p(t) approximately 3.0 GeV/c. A strong p(t) dependence in v(2) is observed up to 2.0 GeV/c. The v(2) measurement is compared with hydrodynamic model calculations. The physics implications of the p(t) integrated v(2) magnitude as a function of particle mass are also discussed.

Journal Article↗
PubMed2002

Midrapidity Lambda and Lambda(macro) production in Au+Au collisions at the square root of [s(NN)]=130 GeV.

We report the first measurement of strange (Lambda) and antistrange (Lambda macro) baryon production from square root of [s(NN)]=130 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Rapidity density and transverse mass distributions at midrapidity are presented as a function of centrality. The yield of Lambda and Lambda; hyperons is found to be approximately proportional to the number of negative hadrons. The production of Lambda; hyperons relative to negative hadrons increases very rapidly with transverse momentum. The magnitude of the increase cannot be described by existing hadronic string fragmentation models alone.

Journal Article↗
PubMed2001

d Macro and (3)He macro production in square root of s(NN) = 130 GeV Au+Au collisions.

The first measurements of light antinucleus production in Au+Au collisions at the Relativistic Heavy-Ion Collider are reported. The observed production rates for d macro and (3)He macro are much larger than in lower energy nucleus-nucleus collisions. A coalescence model analysis of the yields indicates that there is little or no increase in the antinucleon freeze-out volume compared to collisions at CERN SPS energy. These analyses also indicate that the (3)He macro freeze-out volume is smaller than the d macro freeze-out volume.

Journal Article↗
PubMed2001

Measurement of inclusive antiprotons from Au+Au collisions at square root of s(NN) = 130 GeV.

We report the first measurement of inclusive antiproton production at midrapidity in Au+Au collisions at square root of s(NN) = 130 GeV by the STAR experiment at RHIC. The antiproton transverse mass distributions in the measured transverse momentum range of 0.25<p( perpendicular)<0.95 GeV/c are found to fall less steeply for more central collisions. The extrapolated antiproton rapidity density is found to scale approximately with the negative hadron multiplicity density.

Journal Article↗
PubMed2001

Multiplicity distribution and spectra of negatively charged hadrons in Au+Au collisions at square root of (sNN) = 130 GeV.

The minimum-bias multiplicity distribution and the transverse momentum and pseudorapidity distributions for central collisions have been measured for negative hadrons ( h(-)) in Au+Au interactions at square root of ([s(NN)]) = 130 GeV. The multiplicity density at midrapidity for the 5% most central interactions is dN(h(-))/d(eta)/(eta = 0) = 280+/-1(stat)+/-20(syst), an increase per participant of 38% relative to pp collisions at the same energy. The mean transverse momentum is 0.508+/-0.012 GeV/c and is larger than in central Pb+Pb collisions at lower energies. The scaling of the h(-) yield per participant is a strong function of p( perpendicular). The pseudorapidity distribution is almost constant within /eta/<1.

Journal Article↗
PubMed2001

Pion Interferometry of square root of (s(NN)) =130 GeV Au + Au collisions at RHIC.

Two-pion correlation functions in Au+Au collisions at square root of [s(NN)] = 130 GeV have been measured by the STAR (solenoidal tracker at RHIC) detector. The source size extracted by fitting the correlations grows with event multiplicity and decreases with transverse momentum. Anomalously large sizes or emission durations, which have been suggested as signals of quark-gluon plasma formation and rehadronization, are not observed. The Hanbury Brown-Twiss parameters display a weak energy dependence over a broad range in square root of [s(NN)].

Journal Article↗
PubMed2001

Midrapidity antiproton-to-proton ratio from Au+Au collisions at sqrt [s(NN)]=130 GeV.

We report results on the ratio of midrapidity antiproton-to-proton yields in Au+Au collisions at sqrt[s(NN)] = 130 GeV per nucleon pair as measured by the STAR experiment at RHIC. Within the rapidity and transverse momentum range of /y/<0.5 and 0.4<p(t)<1.0 GeV/c, the ratio is essentially independent of either transverse momentum or rapidity, with an average of 0.65+/-0.01((stat))+/-0.07((syst)) for minimum bias collisions. Within errors, no strong centrality dependence is observed. The results indicate that at this RHIC energy, although the p-p pair production becomes important at midrapidity, a significant excess of baryons over antibaryons is still present.

Journal Article↗
PubMed2001

CD34-positive cellular blue nevi.

BACKGROUND: Although cellular blue nevi (CBN) are well known and characterized, the histopathologic and clinical spectrum of these tumors continues to evolve. We report four CBN with a distinctive histologic and immunohistochemical pattern. METHODS: The histologic features and immunohistochemical staining for S-100 protein, HMB-45, Bcl-2 and CD34 of four CBN with distinctive features were evaluated using routine methods and compared to common CBN. RESULTS: All four of these distinctive CBN where known to be congenital, and all showed aggregates of plump spindled cells with round to oval nuclei in aggregates and more slender spindled cells with thin wavy nuclei. The slender, spindled cells showed an infiltrative pattern laterally into the dermis and deep into the subcutaneous fat. All four tumors showed diffuse expression of an immunohistochemical stain for CD34, as well as for S-100 protein, Bcl-2, and HMB-45. CONCLUSION: Positive immunohistochemical staining with the progenitor marker CD34 defines a subset of CBN. These tumors appear to fit within the spectrum of neurocristic cutaneous hamartomas and may arise from more primitive neurocristically derived cells. Further follow-up of these tumors will be necessary to determine whether this subset of CBN defines a subset with a characteristic biologic behavior.

Adolescent↗
PubMed2001

Reduced food intake in response to CGP 71683A may be due to mechanisms other than NPY Y5 receptor blockade.

INTRODUCTION: The purpose of this study was to test the continuing validity of the hypothesis that neuropeptide Y (NPY) produced in the brain controls food intake through an interaction with the NPY Y(5) receptor subtype. METHODS: The hypothesis was tested using CGP 71683A a potent and highly selective non-peptide antagonist of the NPY Y(5) receptor which was administered into the right lateral ventricle of obese Zucker fa/fa rats. RESULTS: Intraventricular injection of 3.4 nmol/kg NPY increased food intake during a 2 h test period. Doses of CGP 71683A in excess of 15 nmol/kg (i.cv.) resulted in blockade of the increase in food intake produced by NPY. Repeated daily injection of CGP 71683A (30--300 nmol/kg, i.cv.) immediately before the dark phase produced a dose-dependent and slowly developing decrease in food intake. CGP 71683A has a low affinity for NPY Y(1), Y(2) and Y(4) receptors but a very high affinity for the NPY Y(5) receptor (Ki, 1.4 nM). Surprisingly, CGP 71683A had similarly high affinity for muscarinic receptors (Ki, 2.7 nM) and for the serotonin uptake recognition site (Ki, 6.2 nM) in rat brain. Anatomic analysis of the brain after treatment with CGP 71683A demonstrated an inflammatory response associated with the fall in food intake. CONCLUSIONS: While the fall in food intake in response to CGP 71683A may have a Y(5) component, interactions with other receptors or inflammatory mediators may also play a role. It is concluded that CGP 71683A is an imprecise tool for investigating the role of the NPY Y(5) receptor in the control of physiological processes including food intake. International Journal of Obesity (2001) 25, 84-94

Animals↗
PubMed2001

Squamous cell carcinoma in situ (Bowen's disease) in renal transplant patients treated with 5% imiquimod and 5% 5-fluorouracil therapy.

BACKGROUND: Depending upon the patient's age at transplant, skin type, sun exposure, and the need for immunosuppressive therapy to prevent rejection, there is escalation in the development of cutaneous malignancies in organ transplant patients a number of years after transplantation. Thus, with the expansion in these procedures over the past decades, and the ever-lengthening survival of these patients, we are seeing an increase in cutaneous malignancies in this patient population. OBJECTIVE: To determine if combined therapy with 5% 5-fluorouracil and 5% imiquimod may be useful in the treatment of squamous cell carcinoma in situ. METHODS: We present five renal transplant patients, all more than 10 years posttransplantation, three with insulin-dependent diabetes, who developed multiple areas of squamous cell carcinoma (SCC) in situ. All these patients were on chronic immunosuppressive chemotherapy to prevent rejection, but were otherwise doing well. All the patients had biopsy-proven SCC in situ on their lower extremities that even in normal patients may be a challenge to treat. RESULTS: We treated these five patients with a combination of a local immune therapy, imiquimod cream, and a topical chemotherapeutic agent, 5% 5-fluorouracil (5-FU), with clearing of the areas of SCC in situ. CONCLUSION: Although immunotherapy must be used with caution in organ transplant patients to avoid graft rejection, topical imiquimod is a local immune modulator that potentiates local innate and possible adaptive immunity without measurable effects on systemic immunity. In addition, there is evidence that cytokines induced by imiquimod may improve the therapeutic efficacy of topical 5% 5-FU in the treatment of SCC in situ.

Administration, Cutaneous↗
PubMed2001

Bowen's disease (squamous cell carcinoma in situ) in immunosuppressed patients treated with imiquimod 5% cream and a cox inhibitor, sulindac: potential applications for this combination of immunotherapy.

BACKGROUND: Patients with chronic lymphocytic leukemia (CLL) often have a protracted course. However, all these patients are immunosuppressed and may have a high incidence of cutaneous malignancies. OBJECTIVE: To determine if combination therapy using topical imiquimod cream 5% and the oral cyclooxygenase (COX) inhibitor are useful in the therapy of squamous cell carcinoma in situ (SCC in situ)/Bowen's disease in patients with long-standing CLL. METHODS: Five CLL patients with head and neck cutaneous SCC in situ, which met criteria for Bowen's disease, were treated with topical 5% topical imiquimod cream and an oral COX inhibitor, sulindac 200 mg twice a day. RESULTS: All patients showed clinical resolution and histologic clearing of the tumors after 16 weeks of therapy. CONCLUSION: The local immune modulator, 5% imiquimod, in combination with a COX inhibitor, with its many potential antitumor effects may stimulate the innate and possibly the adaptive immune responses to clear these malignancies.

Adjuvants, Immunologic↗
PubMed2000

Caspase-3-mediated processing of poly(ADP-ribose) glycohydrolase during apoptosis.

Poly(ADP-ribose) glycohydrolase (PARG) is responsible for the catabolism of poly(ADP-ribose) synthesized by poly(ADP-ribose) polymerase (PARP-1) and other PARP-1-like enzymes. In this work, we report that PARG is cleaved during etoposide-, staurosporine-, and Fas-induced apoptosis in human cells. This cleavage is concomitant with PARP-1 processing and generates two C-terminal fragments of 85 and 74 kDa. In vitro cleavage assays using apoptotic cell extracts showed that a protease of the caspase family is responsible for PARG processing. A complete inhibition of this cleavage was achieved at nanomolar concentrations of the caspase inhibitor acetyl-Asp-Glu-Val-Asp-aldehyde, suggesting the involvement of caspase-3-like proteases. Consistently, recombinant caspase-3 efficiently cleaved PARG in vitro, suggesting the involvement of this protease in PARG processing in vivo. Furthermore, caspase-3-deficient MCF-7 cells did not show any PARG cleavage in response to staurosporine treatment. The cleavage sites identified by site-directed mutagenesis are DEID(256) downward arrow V and the unconventional site MDVD(307) downward arrow N. Kinetic studies have shown similar maximal velocity (V(max)) and affinity (K(m)) for both full-length PARG and its apoptotic fragments, suggesting that caspase-3 may affect PARG function without altering its enzymatic activity. The early cleavage of both PARP-1 and PARG by caspases during apoptosis suggests an important function for poly(ADP-ribose) metabolism regulation during this cell death process.

Animals↗
PubMed2000

Perspectives in dermatopathology: telomeres and telomerase in ageing and cancer; with emphasis on cutaneous disease.

Shortening of telomeres occurs with cell proliferation and correlates well with ageing in humans. Telomerase is a ribonucleoprotein, and is the body's most widely studied mechanism for extension of telomeres to circumvent cellular ageing. Telomerase levels remain at low or unmeasurable levels in most somatic cell populations with only a few exceptions. However, in transformed cell populations, upregulation of telomerase or some other mechanism for telomere extension is required for immortality. The telomere-telomerase system has been proposed to be an adaptation of organisms with prolonged lifespan to avoid malignant tumors, at the cost of the cellular dysfunctions associated with the aged phenotype. Therapies to modulate telomere length and telomerase levels hold promise for therapy of cancer and ageing as well as for genetic conditions that predispose to an aged phenotype.

Aging↗
PubMed2000

The cutaneous cellular infiltrate to stingray envenomization contains increased TIA+ cells.

Stingrays result in approximately 2000 stings annually in the U.S.A., and thus are one of the most important venomous marine animals. After envenomization, there is immediate, intense pain with subsequent oedema, cyanosis followed by local erythema and petechiae. Progressive local necrosis and ulceration is variable, sometimes leading to gangrene. To characterize the inflammatory infiltrate at the site of a stingray injury, we examined tissue obtained approximately 4 days after stingray envenomization. Routine histology and immunohistochemical stains for lymphoid markers, including CD3, CD4, CD8, CD20, KP-1 and TIA were performed, and demonstrated a central area of haemorrhagic necrosis with a surrounding infiltrate of lymphoid cells and eosinophils. Approximately one-third of the mononuclear cells were TIA+, and these cells appeared mainly to correspond to the cells which were CD3+ and CD4+. The inflammatory cells, including the lymphoid populations, suggest that an immunological reaction may contribute to the delayed healing of stingray injuries.

Adult↗