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M J Wood

Publications and source records attributed to M J Wood.

At least 19 recordsLinked to original sources
PubMed1992

Effect of slow and ultra-rapid freezing on cell surface antigens of 8-cell mouse embryos.

The distribution of four cell surface antigens (SSEA-1, SSEA-3, SSEA-4, and I) present on mouse preimplantation embryos was examined on 8-cell stage embryos immediately after flushing from the reproductive tract and after slow or ultra-rapid freezing. Frozen-thawed and nonfrozen embryos were also examined after culture in vitro for 5, 24, or 48 h. Immediately after thawing, embryos showed a disruption in the polarity of cell surface antigens SSEA-3, SSEA-4, and I, but no differences were detected in fluorescence intensity or various other staining characteristics. No long-term changes in the distribution of cell surface components were detected. Implantation and embryonic development were similar for frozen and nonfrozen embryos transferred to the uterine horns of pseudopregnant recipients.

Animals↗
PubMed1992

Effectiveness and duration of intramuscular antimotion sickness medications.

Motion sickness inhibits gastric motility, making the oral route ineffective for medications. The intramuscular route is an effective alternative. The rotating chair was used to produce the M 111 level of motion sickness on the Graybiel Symptom Scale. The intramuscular medications given 30 minutes before rotation were compared with placebo (saline, 1 mL) for effectiveness and duration in increasing the number of tolerated head movements. Average placebo number of head movements was 294. Promethazine 25 mg increased head movements by 78% (P < .05), with a duration of 12 hours. Scopolamine 0.2 mg increased head movements by 91% (P < .05), with a duration of 4 hours. The effect of caffeine 250 mg and ephedrine 25 mg was not significant. When combined with scopolamine, ephedrine produced an 32% additive effect. Scopolamine 0.08 mg, 0.1 mg, and 0.2 mg and also promethazine 12.5 mg and 25 mg were significant (P < .05). Promethazine appears to be the drug of choice for intramuscular use because of a longer duration and a high level of effectiveness. Scopolamine was of high effectiveness, but had a duration of 4 hours. It was eight times as potent by the intramuscular as by the oral route.

Caffeine↗
PubMed1992

A monoclonal antibody to the interleukin-2 receptor enhances the survival of neural allografts: a time-course study.

A time-course study of the survival and immunological characteristics of rat neural allografts was undertaken in animals treated with a murine monoclonal antibody to the alpha-chain (p55) of the rat interleukin-2 receptor. This antibody, NDS 63, was administered for ten days following grafting beginning on the day of operation. Inbred rat strains differing at both major and minor histocompatibility loci were selected as donor and host. Furthermore, the recipient strain displayed a high responder major histocompatibility complex haplotype. All grafts were placed in the lateral ventricle. Comparison was drawn between NDS 63-treated recipients and two groups of controls; an untreated group and a second group treated with the monoclonal antibody NDS 66, directed at a second epitope on the alpha-chain of the interleukin-2 receptor, which has been shown to be ineffective in competing with interleukin-2 for binding. Immunocytochemical analysis of the transplants was performed at several time-points up to 150 days following grafting. Grafts of NDS 63-treated recipients exhibited 100% survival with minimal induction of major histocompatibility complex antigens (both class I and class II) and negligible leukocyte infiltration at all time-points studied. In contrast grafts from both groups of controls showed evidence of a chronic immune response with most grafts undergoing rejection as shown by markedly elevated major histocompatibility complex antigen expression accompanied by specific immune cell infiltration. This was a protracted process with several grafts undergoing complete rejection by 60 days and a majority, but not all, by 150 days after transplantation. It is concluded that NDS 63, a monoclonal antibody to the interleukin-2 receptor, may diminish the immune response to transplanted allogeneic neural tissue and thereby enhance its prospects for long-term survival.

Animals↗
PubMed1992

Fertilization failure of frozen mouse oocytes is not due to premature cortical granule release.

The proportion of mouse oocytes that were fertilized in vitro after storage at -196 degrees C in the presence of 1.5 M dimethylsulfoxide (DMSO) was significantly lower than in unfrozen controls (39% vs. 81%). Sperm failed to penetrate the zona pellucida of approximately 80% of the frozen oocytes that remained unfertilized. Removal of the zona restored fertilization to control levels, indicating that changes induced in the zona during freezing and/or thawing were the primary cause of fertilization failure. Sperm-oocyte fusion, sperm nucleus decondensation, and the resumption of meiosis in frozen oocytes appeared to be delayed but subsequently fertilization progressed normally. No evidence was found to suggest zona modification by the premature release of fucosyl-rich glycoconjugates of cortical granule origin onto the surface of the plasma membrane of frozen oocytes stained immediately after thawing with fluorescently labeled Ulex europaeus lectin. Only a few frozen (less than 5%) and control (less than 3%) oocytes that failed to fertilize in vitro had fucosylated molecules on the plasma membrane. Prolonged exposure of fertilized oocytes to DMSO at 4 degrees C did not alter the pattern of lectin binding. In conclusion, fertilization is inhibited in frozen-thawed oocytes by as yet undefined modifications to the zona pellucida which do not involve the premature release of cortical granules.

Animals↗
PubMed1991

More macrolides.

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Administration, Oral↗
PubMed1991

Neutron and x-ray scatter studies of the histone octamer and amino and carboxyl domain trimmed octamers.

The structure of the nucleosome has been under intense investigation using neutron crystallography, x-ray crystallography, and neutron solution scattering. However the dimension of the histone octamer inside the nucleosome is still a subject of controversy. The radius of gyration (Rg) of the octamer obtained from solution neutron scattering of core particles at 63% 2H2O, 37% 1H2O is 33 A, and x-ray crystallography study of isolated histone octamer gives a Rg of 32.5 A, while the reported values using x-ray crystallography of core particles from two individual studies are 29.7 and 30.4 A, respectively. We report here studies of isolated histone octamer and trypsin-limited digested octamer using both neutron solution scattering and small angle x-ray scattering. The Rg of the octamer obtained is 33 A, whereas that of the trimmed octamer is 29.8 A, similar to the structure obtained from the crystals of the core particles. The N-terminal domains of the core histones in the octamer have been shown by high resolution nuclear magnetic resonance (Schroth, G.P., Yau, P., Imai, B.S., Gatewood, J.M., and Bradbury, E.M. (1990) FEBS Lett. 268, 117-120) to be mobile and flexible; it is likely that these regions are disordered and "not seen" by x-ray crystallography.

Animals↗
PubMed1991

The immune response to intracerebral neural grafts.

Neural transplantation offers a potential therapeutic approach to a variety of neurological disorders, most notably those of a degenerative nature. However, the degree of immunological privilege (i.e. isolation from an immune response) in the brain, which is not absolute, may be a significant impediment to the survival of histoincompatible grafts. The nature of this privilege, together with the specific immune events leading to neural graft rejection, are discussed. As a consequence of this immune-mediated rejection, immunosuppression in some form might be necessary to guarantee long-term graft survival. Various strategies are being explored to suppress the immune response to neural grafts, not only for future use in clinical therapies, but also to bring intracerebral allo- and xenotransplantation to the attention of the general neurobiologist.

Animals↗
PubMed1991

The tolerance and toxicity of clarithromycin.

In a programme of Phase II and III trials, 3437 patients received clarithromycin. Twenty percent of these patients reported adverse events, and three-quarters of these were thought to be possibly or probably linked with the drug. Only 1% of these were severe and most of the adverse events (11% of patients) were digestive system upsets. There was no significant relationship between the dosage of clarithromycin and the incidence of adverse events. Comparison between clarithromycin and the other antibiotics used in controlled trials showed similar side effects reported for beta-lactam agents and clarithromycin but adverse events were reported less frequently with clarithromycin (19%) than with erythromycin (29%) and other macrolides. This was particularly noticeable for adverse events of the digestive system (9% with clarithromycin vs 20% with erythromycin). No significant haematological, hepatic or renal toxicity due to clarithromycin was reported. There may be slight elevation of theophylline levels during concomitant clarithromycin administration.

Adult↗
PubMed1991

Growth in vitro and acquisition of meiotic competence after the cryopreservation of isolated mouse primary ovarian follicles.

The growth and acquisition of meiotic competence of oocytes from fresh and frozen-thawed primary follicles collected from 10-day-old mice was compared during culture in collagen gels for 12 days. The oocytes contained in primary follicles have a mean diameter of about 48 microns and do not resume meiosis without further growth and development. During the 12-day culture period the mean diameter of the oocytes increased to over 60 microns. The oocytes were capable of resuming meiosis when isolated from the gel and cultured in the absence of follicular cells in a manner similar to that observed in vivo. Freezing and thawing did not affect oocyte growth or the ability to resume meiosis; this demonstrates the possibility of storing large numbers of female gametes for subsequent development.

Animals↗
PubMed1991

The clinical presentation and diagnosis of invasive fungal infections.

The frequency of invasive fungal infections is increasing owing to the increasing numbers and improved survival of immuno-compromised patients. The fungi responsible for these infections are predominantly opportunistic pathogens. The clinical features and diagnosis of the four commonest infections (invasive candidosis and aspergillosis, cryptococcosis and mucormycosis) are discussed. Particular emphasis is given to the identification of risk factors for these infections, which are different for each disease. As these organisms are common contaminants or commensals, definitive diagnosis requires culture from sites that are normally sterile or histological demonstration of tissue invasion. Definitive diagnosis is not always possible, in part owing to the severe nature of patients' underlying illnesses. A high proportion of cases are diagnosed post mortem because of difficulties in establishing a diagnosis. Clinical diagnoses thus need to be made early in the course of these infections, but a high index of suspicion and knowledge of the clinical manifestations are required.

Animals↗
PubMed1991

Effects of ginger on motion sickness susceptibility and gastric function.

This study was designed to evaluate the antimotion sickness activity of ginger root (Zingiber officinale) and to characterize the effects of ginger on gastric function. Twenty-eight human volunteers participated in the project. Subjects made timed head movements in a rotating chair until they reached an endpoint of motion sickness short of vomiting (malaise III or M-III). Each subject was tested with either ginger or scopolamine and a placebo. A substance was judged to possess antimotion sickness activity if it allowed a greater number of head movements compared to placebo control. Gastric emptying of a liquid was measured by nuclear medicine techniques in normal and motion sick subjects. Gastric electrical activity was monitored by cutaneous (surface) electrodes positioned over the abdominal area. Powder ginger (whole root, 500 or 1,000 mg) or fresh ginger root (1,000 mg) provided no protection against motion sickness. In contrast, subjects performed an average of 147.5 more head movements (p less than 0.01) after scopolamine (0.6 mg p.o.) than after placebo. The rate of gastric emptying was significantly (p less than 0.05) slowed when tested immediately after M-III but was inhibited less when tested 15 min after M-III. Powdered ginger (500 mg) had no effect on gastric emptying in normal or motion-sick subjects. Gastric motility was also changed during motion sickness. The frequency of the electrogastrogram (EGG) was increased after M-III (tachygastria) and the normal increase in EGG amplitude after liquid ingestion was reduced in motion sick subjects. Although powdered ginger (500 mg) partially inhibited tachygastria in motion sickness, it did not enhance the EGG amplitude in motion sick subjects. We conclude that ginger does not possess antimotion sickness activity, nor does it significantly alter gastric function during motion sickness.

Adolescent↗
PubMed1991

Effect of dibutyryl cyclic adenosine monophosphate on granulosa cell proliferation, oocyte growth and meiotic maturation in isolated mouse primary ovarian follicles cultured in collagen gels.

Isolated primary follicles from 10-day-old mice were cultured in a collagen gel matrix for 6 days in Minimum Essential Medium + foetal calf serum, followed by culture in unsupplemented medium (control) or in medium containing hypoxanthine (2 mM) or dibutyryl cyclic adenosine monophosphate (dbcAMP, 0.25 mM) for a further 3 or 6 days. Less than 10% of oocytes resumed meiosis during the culture period in all groups. At recovery, the diameter of oocytes at the germinal vesicle stage was recorded and their ability to resume meiosis was determined. Hypoxanthine had little effect on oocyte growth and meiotic competence, but culture in dbcAMP resulted in oocytes that were larger (60.2 +/- 0.6 microns) than those of controls (55.8 +/- 0.5 microns) and more competent to resume meiosis than were controls (42.9% and 10.8%, respectively). The addition of dbcAMP to the culture medium induced a 4-5-fold increase in the number of granulosa cells oocyte compared with controls (3757 +/- 423 and 838 +/- 93, respectively). These results indicate that increased oocyte growth and meiotic competence is primarily mediated via dbcAMP effects on the granulosa cells.

Animals↗