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Biomedical subjects

E Cummings

Publications and source records attributed to E Cummings.

16 recordsLinked to original sources

Rate of decline of cortisol concentrations in ovarian follicles following ACTH treatment in the sow.

The rates of decline in cortisol concentrations in blood and ovarian follicular fluid were assessed in cyclic sows (n = 30) after treatment with saline or a depot form of adrenocorticotrophic hormone (ACTH). After a single injection of ACTH (0.5 iu/kg, BW, i.m.), peak cortisol values were achieved in blood within 3 to 4 h followed by a half-life net clearance rate (t1/2 of 2.40 +/- 0.29 (SE) h. The same dose of ACTH was then given at 12 h intervals from days 9 to 13 of the estrous cycle. On day 14 the concentrations of cortisol in follicular fluid were higher (P < 0.05) in ACTH-injected sows than in saline-injected controls. A t1/2 value of 37.81 h was determined for cortisol based on the decline in concentrations in follicular fluid collected on days 14, 16 and 18. This relatively slow rate of removal from developing ovarian follicles may have implications for the previously observed detrimental effects of increased cortisol concentrations on follicular development.

Adrenocorticotropic Hormone

Molecular fragile X screening in normal populations.

In December, 1993, we initiated a pilot project in which DNA fragile X (fraX) testing was offered during routine prenatal or genetic counseling to all pregnant women seen at the Genetics & IVF Institute, most of whom were referred for the indication of advanced maternal age. A brochure on fragile X syndrome was sent to each patient prior to her appointment and was reviewed by a counselor or physician during the counseling session. As of June 1995, 3,345 patients were offered testing; 474 women with no identified family history of mental retardation or learning disability and 214 women with a positive family history accepted the test on a self-pay basis. The second population screened was 271 potential donors in our anonymous egg donor program. DNA from blood was tested by Southern blot using EcoRI/EagI and StB12.3. If an expansion was detected, CGG repeat number was determined by PCR-based analysis. Among the 474 patients with unremarkable family histories, three fraX carriers were identified (repeat sizes = 60+), whereas none were found in the 214 patients with a positive family history. Among the potential egg donors, two high borderline patients were identified (repeat sizes = between 50 and 59). Our ongoing study indicates that screening of pregnant or preconceptual populations for fraX carrier status using DNA testing is accepted by many patients and is an important addition to current medical practice.

Chorionic Villi Sampling

Preliminary findings of altered follicular activity in Holstein cows with coagulation factor XI deficiency.

Factor XI (F XI) deficiency is an autosomal recessive coagulopathy found in Holstein cattle. Affected animals have a 50% greater prevalence of repeat breeding. Therefore, several parameters describing ovarian function were studied. Daily blood sampling revealed that progesterone concentrations were slower to decline from a peak at day 16 (p < 0.01) to values less than 3 nmol/L in F XI-deficient cows (5.14 +/- 0.69 days (mean +/- SD) versus 4.05 +/- 0.63 days in control animals), resulting in an oestrous cycle length of 24.7 +/- 2.1 days compared to 22.9 +/- 3.0 days, respectively. This was not due to an alteration in the availability of prostaglandin F2 alpha (PGF2 alpha) or oxytocin (OT) involved in luteolysis. No significant differences (p > 0.05) were seen between normal (n = 7) and F XI-deficient (n = 7) cows in the peak values or the area under the curve for the pulse in 13,14-dihydro-15-keto PGF2 alpha in response to OT challenge or in the parameters describing the pulse of ovarian OT secretion after PGF2 alpha injection (n = 7 for each) between days 12 and 14. Ovulatory follicular development was assessed by ultrasound monitoring and plasma 17 beta-oestradiol values at 8-h intervals after a luteolytic injection of cloprostenol (n = 6 for each). Follicular diameter was smaller (p < 0.05) and accompanied by lower peak oestradiol values near the time of ovulation in F XI-deficient cows. The results suggest that the oestrous cycle in F XI-deficient cows is characterized by a slower process of luteolysis that may be associated with smaller follicular development.

Animals

Rifampin-induced immune thrombocytopenia. A case report.

In this report, a case of rifampin-induced immune thrombocytopenia with the following characteristics is described: (a) thrombocytopenia follows intermittent drug administration; (b) onset occurs within hours of drug ingestion; (c) IgG antirifampin antibody binds in vitro to normal platelets only in the presence of rifampin; (d) thrombocytopenia resolves quickly in the absence of rifampin; (e) using immunofluorescence microscopy, IgG binding to normal platelets was seen with the patient's serum only in the presence of rifampin, and (f) using fluorescence spectrofluorometry, an absence of rifampin binding to normal platelets was demonstrated. Although the serological studies are not definitive, the mechanism of thrombocytopenia in the patient can best be explained by the formation of immune complexes composed of rifampin-antirifampin antibody binding to platelets causing their rapid clearance from the circulation.

Adolescent

Prevalence of equine onchocerciasis in southeastern and midwestern United States.

Of 664 horses reported to have originated in southeastern and midwestern United States, 341 (51.4%) were positive for Onchocerca cervicalis cutaneous microfilariasis. The highest prevalence of 68.8% was recorded for horses from Virginia. Horses with the highest concentrations of microfilariae (as high as 19,770 microfilariae/mg in 1 horse) were from the Southeast (Georgia, Florida, Tennessee, and Alabama). For horses from South Carolina, the prevalence of infection was 57.1%; from the Midwest (Kentucky, Illinois, Ohio, and Indiana), 54.4%; from North Carolina, 45.5%; from Pennsylvania, 7.7%; and from Minnesota, 5%. Histories and ages of the horses were not known, but most horses were approximately 15 years old. Compared with horses from other states, horses from Pennsylvania were younger, which may have accounted for their lower prevalence of infection.

Abattoirs

Normal survival of Rh0 (D) negative, LW (a+) red cells in a patient with allo-anti LWa.

The serum of an Rh0 (D)+ Caucasian female with a prior history of transfusions contained anti- LWa , reacting moderately with Rh0 (D)+ and weakly with Rh0 (D)- red cells at the antiglobulin phase. Since transfusions were required, Chromium (51Cr) survival studies and mononuclear phagocyte assays (MPA) were used to predict in vivo survival. The MPA value of 6% of the positive control predicted a low likelihood of clinically significant extravascular destruction and 51Cr survival studies indicated greater than 95% survival at 1 h and 78% survival at 20 h for rr erythrocytes. Transfusion of 4 units of Rh0 (D)-, serologically incompatible red cells increased the hemoglobin from 5.2 to 11.4 g/dl and the titer of anti- LWa against rr red cells from 4 to 1,024 7 days after the transfusion. A second 51Cr survival also indicated normal survival of rr erythrocytes. 3 additional Rh0 (D)- units were successfully transfused.

Aged

Initiation of quail and mouse mandibular chondrogenesis and osteogenesis in a serumless, chemically-defined medium.

To evaluate the requirement of vascular and/or neurotrophic-derived factors on determination and differentiation of chondrogenic and osteogenic phenotypes, early embryonic quail and mouse mandibular processes were cultured using a modified Trowell method in a serumless, chemically-defined medium for 10 days. Quail HH stage 22 and mouse Theiler stage 16 mandibular processes formed cartilage and produced osteoid under these experimental conditions. Chondrogenic and osteogenic phenotypes were expressed without serum or other exogenous growth-promoting influences.

Animals

Epithelial-derived basal lamina regulation of mesenchymal cell differentiation.

The mechanisms by which epithelial-mesenchymal interactions result in differentiation are not known. A number of recombinations between vertebrate tissues associated with epidermal organs (e.g. skin, feather, mammary gland, salivary gland, tooth organ) indicate that regional mesenchymal specificity is instructive for determination and differentiation of epithelial phenotypes. In epidermal organs within which mesenchyme becomes determined and differentiates into a unique phenotype, such as during tooth organogenesis and odontoblast differentiation. Does the epithelial-derived basal lamina regulate mesenchymal differentiation into odontoblasts and the expression of dentine extracellular matrix? Experiments were designed to test the hypothesis that murine or avian epithelial-derived basal lamina possess information which is instructive for determined dental mesenchyme to differentiate into odontoblasts. The strategy was to examine homologous and heterologous tissue recombinants between Theiler stage 25 C57BL/6 molar tooth organs and Hamburger-Hamilton equivalent stage 22-26 Japanese Pharoah quail mandibular processes. Trypsin-dissociated molar epithelium and mesenchyme, reconstituted, secreted a basal lamina within 8 hours and mesenchyme differentiated into odontoblasts and formed dentine matrix within 3 days. Isolated trypsin-dissociated mesenchyme did not differentiate in vitro, whereas heterologous recombinants between odontogenic mesenchyma and quail epithelia resulted in odontoblasts and dentine production. Mouse tooth or quail mandibular epithelia served to regulate odontogenic mesenchyme differentiation. EDTA-dissociated mouse molar mesenchyme, in the absence of epithelium but with adherent basal lamina, routinely differentiated into odontoblasts. Control tooth organs routinely formed both dentine and enamel extracellular matrices within 7-10 days in our serumless, chemically-defined organ culture system. Regulation of determined mesenchymal cells to differentiate into functional and highly specialized odontoblasts appears to be mediated by epithelial-derived basal lamina and is not species or organ-specific.

Animals

The usefulness of NOR and RFA banding in prenatal diagnosis: a case report.

Prenatal chromosome analysis of amniotic cells showed a male fetus to carry an unusual marker D chromosome containing extra genetic material on the short arm, which could be interpreted as a possible t(D;G) or t(D;Fq) unbalanced translocation using non-branded preparations or a routine GTG band method. Analysis of this marker by NOR and RFA banding and parental chromosome studies showed the marker to be an unusual variant of the satellited area of chromosome 15, with no associated phenotypic anomalies. The usefulness of NOR and RFA banding as aids in chromosome identification in prenatal diagnosis is discussed.

Acridine Orange

Chemically-defined organ culture of embryonic mouse tooth organs: morphogenesis, dentinogenesis and amelogenesis.

Chemically-defined in vitro conditions without serum have been identified which are permissive for embryonic mouse tooth organs to express morphogenesis and cytodifferentiation. In the absence of antibiotics, embryonic extracts, autologous and/or heterologous sera, molar tooth organs from Theiler stage 25 embryos (C57BL/6, A/Jax and Tabby mouse strains) routinely formed discrete dentin and enamel extracellular organic matrices within 10 days of continuous in vitro cultivation. Collagen and non-collagenous protein synthesis and secretion by differentiated cells within explants, between 9 and 10 days in vitro, were studied with light microscopic autoradiography. Finally, explants of embryonic mouse molar tooth organs have been maintained in organ culture for three week without serum supplementation.

Amelogenesis

Pediatric home healthcare: a paradox.

Although parents may welcome having their ill child cared for at home, they are not prepared to compromise privacy and family rituals, nor share control of their child. The purpose of this article is to provide a snapshot of problems that parents have encountered with pediatric home healthcare. Home care parents offer suggestions for other parents and home healthcare nurses and agencies, encouraging them to be proactive in preventing potential problems.

Child