Biomedical subjects

L Gras

Publications and source records attributed to L Gras.

At least 19 recordsLinked to original sources

PubMed2003

Effect of timing and type of treatment on the risk of mother to child transmission of Toxoplasma gondii.

OBJECTIVE: To determine the effects on mother to child transmission of the timing and type of prenatal treatment, taking into account gestational age at maternal seroconversion. DESIGN: Prospective cohort study. SETTING: European centres offering prenatal screening for toxoplasmosis. POPULATION: Children born to a cohort of pregnant women with toxoplasma infection. METHODS: We determined the effects on mother to child transmission of the interval between seroconversion and start of treatment (treatment delay), and the type of treatment, taking into account gestational age at maternal seroconversion. MAIN OUTCOME MEASURE: Congenital infection status confirmed by toxoplasma IgG results at one year postnatal age. RESULTS: Of 1208 women analysed, 72% were first prescribed spiramycin, 19% pyrimethamine-sulphonamide and 9% (mostly infected during the last trimester) were untreated. The odds ratios for mother to child transmission for all women treated after a delay of four to seven weeks was 0.77 (95% CI 0.34-1.69), and after eight weeks or more was 1.33 (0.56-2.89) compared with less than four weeks. The odds ratio per week of treatment delay was 1.01 (0.93-1.08). There was no evidence that transmission risk differed in women first treated with pyrimethamine-sulphonamide versus spiramycin: odds ratio 1.10 (0.63-1.91) or in untreated versus treated women: odds ratio 0.57 (0.27-1.17). CONCLUSION: We were unable to demonstrate a beneficial effect of the timing or type of prenatal treatment on the risk of mother to child transmission but we could not exclude a clinically important effect. Randomised controlled trials are required to determine the effect of prenatal treatment on mother to child transmission.

Adult↗

PubMed2002

Reliability of expert interpretation of retinal photographs for the diagnosis of toxoplasma retinochoroiditis.

AIMS: To measure agreement and estimate sensitivity and specificity of uveitis experts' interpretation of retinal photographs for the diagnosis of toxoplasma retinochoroiditis. METHODS: The authors collated 96 retinal photographs from patients presenting with symptomatic posterior uveitis to ophthalmology clinics within a defined geographical area. Five uveitis experts independently ranked each photograph as definite, probable, possible, or not toxoplasma retinochoroiditis. They measured interobserver agreement based on an intraclass correlation coefficient and estimated sensitivity and specificity for each observer using a maximum likelihood model. RESULTS: The intraclass correlation coefficient for all five observers was 0.62 (95% CI: 0.54 to 0.69). Estimates of sensitivity and specificity for individual observers ranged from 71% to 96% and 58% to 100% respectively when appearances were dichotomised as definite or probable toxoplasma retinochoroiditis, versus possible or not. CONCLUSION: Agreement between uveitis experts on the interpretation of retinal photographs was moderate to good, but the estimates of sensitivity and specificity of their interpretation for the diagnosis of toxoplasma retinochoroiditis were highly variable. Assuming that interpretation of photographs is similar to real time ophthalmoscopy, clinicians need to beware that treatment decisions made on the basis of a single assessment will include patients without toxoplasma retinochoroiditis and will miss patients with the disease.

Acute Disease↗

PubMed2001

Effect of prenatal treatment on mother to child transmission of Toxoplasma gondii: retrospective cohort study of 554 mother-child pairs in Lyon, France.

BACKGROUND: The aim of prenatal serological screening for toxoplasmosis is to identify and treat maternal infection as soon as possible in order to prevent transmission of the parasite to the fetus. However, despite widespread provision of prenatal toxoplasma screening across Europe, the effectiveness of prenatal treatment is uncertain. The study aimed to determine the effect of the timing and type of prenatal treatment on mother to child transmission of Toxoplasma gondii. METHOD: A cohort of 554 infected pregnant women were identified in Lyon, France between 1987 and 1995 and their children were followed to determine congenital infection status. We determined the effect of prenatal treatment on transmission by examining the effect of the delay between maternal seroconversion and start of treatment. We also compared the effect of the type of treatment and no treatment on the risk of mother to child transmission. Analyses were adjusted for gestation at maternal seroconversion. RESULTS: Compared to treatment within 4 weeks from seroconversion, the adjusted odds ratios (OR) for mother to child transmission after a treatment delay of 4-7 weeks was 1.29 (95% CI : 0.61, 2.73) and after more than 8 weeks, 1.44 (95% CI : 0.60, 3.31). The adjusted OR associated with spiramycin alone compared with pyrimethamine-sulfadiazine treatment was 0.91 (95% CI : 0.45, 1.84) and the OR for no treatment compared with pyrimethamine-sulfadiazine treatment was 1.06 (95% CI : 0.37, 3.03). CONCLUSIONS: The authors hypothesize that the absence of an effect of prenatal treatment is due to transmission before the start of treatment.

Adult↗

PubMed2001

Effect of prenatal treatment on the risk of intracranial and ocular lesions in children with congenital toxoplasmosis.

BACKGROUND: Hydrocephalus, intracranial calcification and retinochoroiditis are the most common manifestations of tissue damage due to congenital toxoplasmosis, but the effect of prenatal treatment on these outcomes is unclear. We aimed to determine the effect of prenatal treatment for toxoplasmosis on the risk of intracranial and ocular lesions in congenitally infected children at 3 years of age. METHODS: A cohort of mothers identified during pregnancy with toxoplasma infection and their 181 liveborn children with confirmed congenital toxoplasmosis was retrospectively analysed to determine the presence of intracranial and ocular lesions. As few women are not treated, we compared the effects of the treatment potency (pyrimethamine-sulfadiazine versus spiramycin or no treatment), and the timing of treatment, on the risks of intracranial lesions, time to detection of ocular lesions, and detection of any lesions (intracranial or ocular) by 3 years of age. Analyses took account of the gestation at maternal seroconversion. RESULTS: There was no evidence for an effect of pyrimethamine-sulfadiazine on intracranial, ocular or any lesions by 3 years: odds ratio (OR) for any lesions 0.89 (95% CI : 0.41, 1.88). There was no evidence of an effect of delayed treatment on ocular lesions (hazard ratio = 0.69, 95% CI : 0.28, 1.68) or any lesions by 3 years of age (OR = 0.44, 95% CI : 0.16, 1.19). CONCLUSIONS: Our study failed to detect a beneficial effect of early or more potent anti toxoplasma treatment on the risks of intracranial or ocular lesions in children with congenital toxoplasmosis. However, larger, prospective studies, which determine the effect of prenatal treatment on long-term developmental outcomes are required to justify changes in clinical practice.

Anti-Bacterial Agents↗

PubMed2000

Chromosome mosaicism in day 3 aneuploid embryos that develop to morphologically normal blastocysts in vitro.

In all, 143 human embryos obtained 3 days (day 3) after insemination or intracytoplasmic sperm injection (ICSI) were biopsied and a single nucleated cell removed for identification of aneuploidy by fluorescent in-situ hybridization (FISH) for chromosomes X, Y, 13, 16, 18 and 21. Fifty-one per cent of embryos were aneuploid and significantly more aneuploid embryos blocked in further development to morulae and blastocysts than euploid embryos (59 versus 34%; P < 0.001). Chromosomal analysis of the generated blastocysts revealed 40% were aneuploid (16 of 40 generated blastocysts). Re-examination of cells by FISH for the same chromosome probes of the inner cell mass (ICM) of expanded and hatching blastocysts derived from the aneuploid embryos revealed a high incidence of mosaicism of ICM cell lineages that were usually predictable from observations of day 3 single-cell biopsies. These data would not support the hypothesis of a preferential allocation of euploid cells to the ICM and aneuploid cells to the trophectoderm. A high concordance between day 3 aneuploidy diagnosis and ICM cell lineages was observed with trisomies (97%), and multiple complex chromosome numerical abnormalities (100%). A reduced concordance was observed with monosomies (65%) and haploidy (18%). Concomitantly, the proportion of ICM cell lineages was increased in blastocysts whose chromosomal condition was diagnosed as haploid (21%) or with complex numerical abnormalities (50%).

Aneuploidy↗

PubMed1999

Docetaxel and cisplatin: an active regimen in patients with locally advanced, recurrent or metastatic squamous cell carcinoma of the head and neck. Results of a phase II study of the EORTC Early Clinical Studies Group.

BACKGROUND: Docetaxel and cisplatin are among the most active antitumor agents in head and neck cancer, and phase I studies found the combination of the two drugs to be feasible. The EORTC ECSG performed a multicenter phase II study in patients with locally advanced, recurrent or metastatic squamous cell carcinoma of the head and neck to evaluate the antitumor efficacy and toxicity of this combination. PATIENTS AND METHODS: Eligibility criteria included written informed consent, a WHO performance status < 2, life expectancy of > 12 weeks, and adequate bone marrow, liver and renal function. Neoadjuvant pretreatment with cisplatin-based chemotherapy or prior radiotherapy were allowed. Patients were ineligible if pretreated with taxoids, had CNS involvement, concurrent malignancy, peripheral neuropathy, or no measurable disease. Treatment consisted of docetaxel 100 mg/m2 (one-hour i.v. infusion), followed by cisplatin 75 mg/m2 (three-hour i.v. infusion), repeated every three weeks. Supportive care included hydration, 5HT3-antagonists, and corticosteroids. RESULTS: Forty-four patients (median age 55 years, range 35-76) entered the trial; 41 patients were eligible, 164 cycles of treatment were evaluable for toxicity, and 31 patients for response. Fourteen patients had undergone prior surgery, 15 had received radiotherapy, and five had had chemotherapy. A median number of four treatment cycles (range 1-6) was given. Hematologic and non-hematologic toxicities were common, but hypersensitivity reactions and fluid retention were very infrequent due to corticosteroid prophylaxis. Four patients were taken off the study due to toxicity, and one toxic death occurred due to pneumonia. Among 41 eligible patients, objective responses as confirmed by independent review included six complete remissions and 16 partial remissions, resulting in an overall response rate of 53.7% (95% confidence interval: 37.4%-69.3%). Responses occurred in locally advanced, recurrent and metastatic disease, both in pre- and non-pretreated patients. Of 22 evaluable, non-pretreated patients with locally advanced or metastatic disease, five achieved complete responses, and 14 partial responses. Observed among nine evaluable pretreated patients with locally advanced or metastatic head and neck cancer were one complete response and two partial responses. CONCLUSION: The combination of docetaxel and cisplatin is feasible and active in locally advanced, recurrent, and metastatic squamous cell carcinoma of the head and neck.

Adult↗

PubMed1999

Diffuse large B-cell non-Hodgkin lymphomas: the clinical relevance of histological subclassification.

In the REAL classification the diffuse large B-cell non-Hodgkin lymphomas (NHL) are grouped together, because subclassifications are considered to lack both reproducibility and clinical significance. Others, however, claim that patients with an immunoblastic NHL have a worse prognosis than patients with other types of diffuse large B-cell NHL. Therefore, we investigated the prognostic and clinical significance of histological subclassification of diffuse large B-cell NHL in a uniformly treated series of patients. For this retrospective study, all patients diagnosed as having an immunoblastic (IB) B-cell NHL by the Lymphoma Review Panel of the Comprehensive Cancer Center Amsterdam (CCCA) between 1984 and 1994, and treated according to the guidelines of the CCCA, were analysed. Patients with a centroblastic polymorphic subtype (CB-Poly) or centroblastic (CB) NHL by the Lymphoma Review Panel who were treated in the Netherlands Cancer Institute during the same period according to CCCA guidelines were used as reference groups. All patients' records were reviewed. Clinical parameters at presentation, kind of therapy and clinical outcome were recorded. All available histological slides were separately reviewed by two haemato-pathologists. One hundred and seventy-seven patients were included in the study: 36 patients (20.3%) with an IB NHL, 69 patients (39%) with a CB-Poly NHL and 72 patients (40.7%) with a CB NHL. The patients with an IB NHL tended to be older and presented more often with stage I or II and one extranodal site than patients with a CB and CB-Poly NHL. None of the subtypes showed a clear preference for localization in a particular site. The patients with IB or CB-Poly NHL showed a significantly worse prognosis than patients with CB NHL, with a 5-year overall survival for patients with CB NHL of 56.3% and for patients with IB or CB-Poly NHL 39.1% and 41.6% respectively. The 5-year disease free survival was 53.2% for the patients with CB, 32% for the patients with CB-Poly and 26.9% for the patients with IB NHL. A multivariate analysis showed that histological subtyping was of prognostic significance independent of the International Prognostic Index. This finding merits further exploration in prospective studies in order to judge the value of subclassification of large B-cell NHL as a guideline in therapy choice.

Aged↗

PubMed1999

Pregnancy and birth resulting from transfer of a blastocyst observed to have one pronucleus at the time of examination for fertilization.

This case report describes a successful full-term pregnancy and birth after the transfer of a zona-free blastocyst derived from an oocyte observed at fertilization check as having only one distinct pronucleus (PN). The patient had previously undergone four in-vitro fertilization (IVF) cycles and three frozen embryo transfer cycles, with one pregnancy resulting. In this IVF cycle, 7/19 oocytes were fertilized exhibiting two distinct PN; however, all these oocyctes failed to develop in culture and had arrested or totally fragmented by day 6 after insemination. One oocyte (1/19) displayed only one PN 18 h after insemination, but culture of this oocyte led to development of an early cavitating blastocyst by day 6. Since no other embryos were available for transfer to the patient, this embryo was transferred, resulting in a full-term pregnancy with delivery of a normal healthy boy. Observation of a single PN at the normal time of fertilization assessment would not appear to be an absolute indicator of developmental incompetence. In-vitro culture to 6 days post-insemination provides the opportunity to assess embryological development after activation of the embryonic genome. Formation of a morphologically normal blastocyst may be an indicator of a fertilized embryo with normal developmental capacity.

Adult↗

PubMed1999

Notes from England.

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Attitude of Health Personnel↗

PubMed1998

Estimation of the incidence of late bladder and rectum complications after high-dose (70-78 GY) conformal radiotherapy for prostate cancer, using dose-volume histograms.

PURPOSE: To investigate whether Dose-Volume Histogram (DVH) parameters can be used to identify risk groups for developing late gastrointestinal (GI) and genitourinary (GU) complications after conformal radiotherapy for prostate cancer. METHODS AND MATERIALS: DVH parameters were analyzed for 130 patients with localized prostate cancer, treated with conformal radiotherapy in a dose-escalating protocol (70-78 Gy, 2 Gy per fraction). The incidence of late (>6 months) GI and GU complications was classified using the RTOG/EORTC and the SOMA/LENT scoring system. In addition, GI complications were divided in nonsevere and severe (requiring one or more laser treatments or blood transfusions) rectal bleeding. The median follow-up time was 24 months. We investigated whether rectal and bladder wall volumes, irradiated to various dose levels, correlated with the observed actuarial incidences of GI and GU complications, using volume as a continuous variable. Subsequently, for each dose level in the DVH, the rectal wall volumes were dichotomized using different volumes as cutoff levels. The impact of the total radiation dose, and the maximum radiation dose in the rectal and bladder wall was analyzed as well. RESULTS: The actuarial incidence at 2 years for GI complications > or =Grade II was 14% (RTOG/EORTC) or 20% (SOMA/LENT); for GU complications > or =Grade III 8% (RTOG/EORTC) or 21% (SOMA/LENT). Neither for GI complications > or =Grade II (RTOG/EORTC or SOMA/LENT), nor for GU complications > or =Grade III (RTOG/EORTC or SOMA/LENT), was a significant correlation found between any of the DVH parameters and the actuarial incidence of complications. For severe rectal bleeding (actuarial incidence at 2 years 3%), four consecutive volume cutoff levels were found, which significantly discriminated between high and low risk. A trend was observed that a total radiation dose > or = 74 Gy (or a maximum radiation dose in the rectal wall >75 Gy) resulted in a higher incidence of severe rectal bleeding (p = 0.07). CONCLUSIONS: These data show that dose escalation up to 78 Gy, using a conformal technique, is feasible. However, these data have also demonstrated that the incidence of severe late rectal bleeding is increased above certain dose-volume thresholds.

Dose-Response Relationship, Radiation↗

PubMed1997

Differential pathogenesis of lethal mousepox in congenic DBA/2 mice implicates natural killer cell receptor NKR-P1 in necrotizing hepatitis and the fifth component of complement in recruitment of circulating leukocytes to spleen.

Innate resistance of C57BL/6 (B6) mice to lethal mousepox is controlled by multiple genes. Previously, four resistance genes were localized to specific subchromosomal regions and transferred onto a susceptible DBA/2 (D2) background by serial backcrossing and intercrossing to produce congenic strains. Intraperitoneally inoculated ectromelia virus was uniformly lethal and achieved similar titers in B6 and D2 mice but elicited differential responses in liver, spleen, and circulating blood leukocytes. The distribution of these response phenotypes in congenic strains linked control of phenotypes with specific subchromosomal regions. D2.R1 mice, which carried a differential segment of chromosome 6, exhibited a B6 liver response and intermediate spleen and circulating leukocyte responses. D2.R2 and D2.R4 mice, which carried differential segments of chromosomes 2 and 1, respectively, exhibited a D2 liver response, a B6 spleen response, and an intermediate circulating leukocyte response. The localization of control of liver response phenotypes to chromosome 6 implicates cells that express natural killer (NK) cell receptor NKR-P1 alloantigens. The localization of control of spleen and circulating leukocyte responses to chromosomes 1, 2, and 6 implicates NK cells, the fifth component of complement, and a gene near the selectin gene complex in recruitment of circulating leukocytes to spleen.

Animals↗

PubMed1995

Chromosome mapping of Rmp-4, a gonad-dependent gene encoding host resistance to mousepox.

DBA/2 (D2) mice are susceptible and C57BL/6 (B6) mice are resistant to lethal mousepox. A congenic resistant strain, D2.B6-Rmp-4r (D2.R4), was developed by serially backcrossing male mice that survived ectromelia virus infection with D2 mice, beginning with (B6 x D2)F1 mice. Male D2.R4 mice were at least 300-fold more resistant to lethal mousepox than male D2 mice. Female D2.R4 mice were 100-fold more resistant than male D2.R4 mice and 500-fold more resistant than female D2 mice. Neonatal gonadectomy prevented development of resistance in D2.R4 mice of both sexes. Differences in resistance between strains and between sexes correlated with restriction of virus replication in spleen and liver, but gender differences were less evident in liver than in spleen. High-resolution interval mapping of the 19 autosomes of D2.R4 mice using dispersed informative microsatellites as marker loci revealed a segment of distal chromosome 1 to be of B6 origin. Haplotypes for a marker locus, D1Mit57, from the differential segment were determined in (D2.R4 x D2)F1 x D2 backcross mice, which were then infected with ectromelia virus. Significantly more heterozygotes than homozygotes survived ectromelia virus infection in both sexes. Whereas nearly all surviving males were heterozygotes, 44% of surviving females were homozygotes. These results indicate that resistance in D2.R4 mice is determined by a gonad-dependent gene on distal chromosome 1, provisionally named Rmp-4, and by an ovary-dependent factor that is not genetically linked to Rmp-4.

Animals↗

PubMed1993

Ectromelia virus replication in major target organs of innately resistant and susceptible mice after intravenous infection.

The kinetics of ectromelia virus replication in the spleen and liver and of alpha/beta interferon production in the spleen were determined during the first 3 days after intravenous infection with the virulent Moscow strain in resistant C57 BL/6 and susceptible DBA/2 mice. Virus replication in the spleen as measured by assays for virus DNA and infectious centers was suppressed in C57BL/6 mice relative to DBA/2 mice within the first 1 or 2 days of infection. Infectious centers increased in DBA/2 mice but not in C57 BL/6 mice. Differences in virus replication between strains were less discrete when spleens were assayed for infectious virus than when they were assayed for infectious centers because infectious centers of most C57 BL/6 mice had more infectious virus than infectious centers of DBA/2 mice. Virus replication in the liver, the major target organ, as measured by virus DNA and infectious virus assays, was suppressed in C57 BL/6 mice relative to DBA/2 mice 3 days after infection but not before that interval. The results indicate that genetic control of ectromelia virus replication begins within the first 1 or 2 days of infection in the spleen but is delayed in the liver and that genetic control is directed at the prevention of virus spread more than at virus replication.

Animals↗

PubMed1992

The incidence of chromosomal aneuploidy in stimulated and unstimulated (natural) uninseminated human oocytes.

The incidence of chromosomal aneuploidy in human oocytes is higher than for various animal species. Since this estimate for aneuploidies is based on data obtained from in-vitro fertilization (IVF) patients, it is possible that superovulation could be contributing to this phenomenon. In this study we determine the incidence of chromosomal aneuploidy in nonstimulated uninseminated human oocytes donated by IVF patients. Furthermore, we compare this incidence of aneuploidy to that obtained after superovulation using two different protocols for induction of multiple follicular growth. The rate of aneuploidy in non-stimulated oocytes was 20% (4/20). This is not significantly different from the rate of aneuploidy in oocytes obtained after superovulation with clomiphene/human menopausal gonadotrophin (HMG)/(HCG) (15/43 = 35%, chi 2 = 1.11; P > 0.20), buserelin-flare (8/25 = 32%; chi 2 = 0.32; P > 0.05), and the rate of aneuploidy in the total number of superovulated oocytes (23/68 = 34%; chi 2 = 82; P < 0.30). Furthermore, the incidence of chromosome aneuploidy in non-stimulated uninseminated oocytes (20%) was well within the range and not significantly different from that reported in the literature for both superovulated uninseminated oocytes (range, 21-57%; total aneuploidy rate, 67/216 = 31%; P < 0.30) and superovulated inseminated oocytes (range, 3-56%; total aneuploidy, 339/1480 = 23%; P < 0.95). Consequently, the data provide evidence that superovulation protocols used in IVF may not be responsible for the higher rate of aneuploidy in human oocytes. These results are discussed in relation to hypotheses on the occurrence of meiotic non-disjunction.

Adult↗

PubMed1992

Serial backcross analysis of genetic resistance to mousepox, using marker loci for Rmp-2 and Rmp-3.

At least three genes from C57BL/6 mice that mediate dominant resistance to lethal mousepox were isolated and transferred onto a susceptible DBA/2 background. Three [(C57BL/6 x DBA/2)F1 x DBA/2] male mice that survived infection were selected as founders on the basis of different complements of marker loci for two resistance genes, Rmp-2r (Hc1) and Rmp-3r (H-2Db). They were crossed with DBA/2 mice, male progeny were infected with ectromelia virus, and the cycle was repeated with surviving male progeny through seven backcross generations. Two founders carried a marker locus for Rmp-2r or Rmp-3r, and the third carried neither marker locus. Resistance pedigrees were analyzed for passage of marker loci. From the three founders, resistance was passaged through multiple generations, producing backcross lines with intermediate-male-resistance phenotypes (20% resistant). Females of backcross lines with intermediate male resistance had high resistance (> 50%). High-resistance backcross lines (40% male resistance) also developed from the founders that carried marker loci for Rmp-2r and Rmp-3r, and marker loci were passaged through all generations of high resistance but not intermediate-resistance lines. About one-third of all resistant mice in high-resistance lines sired by mice that carried marker loci for Rmp-2r and Rmp-3r did not carry the respective marker locus. In lines that carried Rmp-2r, this was apparently not the result of recombination between Rmp-2r and Hc1, because Rmp-2 was not in the predicted location on chromosome 2 and because mice that did not inherit Hc1 transmitted significantly less male resistance than Hc1-positive mice, although female resistance remained high. These results confirmed that C57BL/6 mice have redundant resistance mechanisms, two of which are controlled at least in part by Rmp-2r and Rmp-3r, and provided evidence for a fourth resistance gene, herein presumptively named Rmp-4, which protects females more than males and which may be epistatic to Rmp-2.

Animals↗

PubMed1991

Chromosomal locations and gonadal dependence of genes that mediate resistance to ectromelia (mousepox) virus-induced mortality.

Four genetic loci were tested for linkage with loci that control genetic resistance to lethal ectromelia virus infection in mice. Three of the loci were selected because of concordance with genotypes assigned to recombinant inbred (RI) strains of mice derived from resistant C57BL/6 and susceptible DBA/2 (BXD) mice on the basis of their responses to challenge infection. Thirty-six of 167 male (C57BL/6 x DBA/2)F1 x DBA/2 backcross (BC) mice died (22%), of which 27 (75%) were homozygous for DBA/2 alleles at Hc and H-2D. Twenty-eight percent of sham-castrated and 6% of sham-ovariectomized BC mice were susceptible to lethal mousepox, whereas 50% of gonadectomized mice were susceptible. There was no linkage evident between Hc or H-2D and loci that controlled resistance to lethal ectromelia virus infection in 44 castrated BC mice. Mortality among female mice of BXD RI strains with susceptible or intermediate male phenotypes was strongly correlated (r = 0.834) with male mortality. Gonadectomized C57BL/6 mice were as resistant as intact mice to lethal ectromelia virus infection. These results indicate that two gonad-dependent genes on chromosomes 2 and 17 and one gonad-independent gene control resistance to mousepox virus infection, that males and females share gonad-dependent genes, and that the gonad-independent gene is fully protective.

Alleles↗

PubMed1988

Mousepox in inbred mice innately resistant or susceptible to lethal infection with ectromelia virus. IV. Studies with the Moscow strain.

The pathogenesis and transmission of infection with the Moscow strain of ectromelia virus were studied in inbred mice. BALB/cAnNcr had high morbidity and mortality and C57BL/6Ncr (B6) mice had high morbidity and low mortality. Virus was detected in B6 mice for 2 weeks after subcutaneous (s.c.) inoculation and infected mice developed lesions compatible with acute mousepox. B6 inoculated by footpad transmitted infection to cagemates for up to five weeks and soiled cages that had housed infected mice were infectious for three weeks. S.c.-inoculated B6 mice also transmitted by contact for 2 weeks. Transmission was attributed to oronasal excretion of virus. Airborne transmission of infection between adjacent cages occurred at a low rate. Ectromelia virus-free progeny were derived from previously infected dams. These studies indicate that the highly virulent and infectious Moscow strain of ectromelia virus caused self-limiting infection in inbred mice and that direct contact is the most efficient means of transmission. These findings support the concept that mousepox can be contained by husbandry practices that minimize or eliminate the spread of infection by direct contact or fomites.

Animals↗

PubMed1980

Two dicentric Y isochromosomes, one without and the Yqh heterochromatic segment: review of the Y isochromosomes.

Two women with primary amenorrhoea and few other stigmata of Turner's syndrome were found to be chromosome mosaics: 45,X/46,X,idic(Y). In Case 1, the dicentric isochromosome Y was found to have a long-arm breakpoint of formation. This structure was interpreted as containing two Y short arms and centromeres separated by a region derived from the proximal Y long arm. One of the centromeres in the Case 1--idic(Y) was suppressed in 80% of cells in blood, and in these cells it appeared as a regular Y-shaped chromosome. In Case 2 the idic(Y) was derived by a short-arm breakpoint of formation. In all the dicentrics of this case with one primary constriction (functional monocentrics) there was a single Cd band. In the 10% of dicentrics with two primary constrictions, there were two Cd bands. It is argued that the instability of sex isochromosomes is due to this functional dicentricity in some cells. These cases are compared with 42 other Y isochromosomes with various short- and long-arm breakpoints of formation. It is suggested that some of the nonheterochromatic, nonfluorescent Y chromosomes previously reported may be explained as dicentric i(Y) with proximal long-arm breakpoints of formation and one suppressed centromere.

Adolescent↗