Incidence of acquired demyelination of the CNS in Canadian children.

BACKGROUND: The incidence of acquired demyelination of the CNS (acquired demyelinating syndromes [ADS]) in children is unknown. It is important that physicians recognize the features of ADS to facilitate care and to appreciate the future risk of multiple sclerosis (MS). OBJECTIVE: To determine the incidence, clinical features, familial autoimmune history, and acute management of Canadian children with ADS. METHODS: Incidence and case-specific data were obtained through the Canadian Pediatric Surveillance Program from April 1, 2004, to March 31, 2007. Before study initiation, a survey was sent to all pediatric health care providers to determine awareness of MS as a potential outcome of ADS in children. RESULTS: Two hundred nineteen children with ADS (mean age 10.5 years, range 0.66-18.0 years; female to male ratio 1.09:1) were reported. The most common presentations were optic neuritis (ON; n = 51, 23%), acute disseminated encephalomyelitis (ADEM; n = 49, 22%), and transverse myelitis (TM; n = 48, 22%). Children with ADEM were more likely to be younger than 10 years, whereas children with monolesional ADS (ON, TM, other) were more likely to be older than 10 years (p < 0.001). There were 73 incident cases per year, leading to an annual incidence of 0.9 per 100,000 Canadian children. A family history of MS was reported in 8%. Before study initiation, 65% of physicians indicated that they considered MS as a possible outcome of ADS in children. This increased to 74% in year 1, 81% in year 2, and 87% in year 3. CONCLUSION: The incidence of pediatric acquired demyelinating syndromes (ADS) is 0.9 per 100,000 Canadian children. ADS presentations are influenced by age.

Evaluation of members of the TGFbeta superfamily as candidates for the oocyte factors that control mouse cumulus expansion and steroidogenesis.

Oocytes secrete factors that control cumulus and granulosa functions, including cumulus expansion and steroid hormone production. Some members of the transforming growth factor beta (TGFbeta) superfamily influence these activities, yet it is still not determined conclusively whether any of these superfamily members are the previously reported oocyte-secreted factors. The aim of this study was to examine the effects of TGFbeta1 and growth differentiation factor 9 (GDF-9) on cumulus expansion and progesterone production by mouse oocytectomized (OOX) complexes in culture. TGFbeta1 mimics the effects of oocytes by both enabling cumulus expansion and inhibiting progesterone production; however, neutralizing antibodies to TGFbeta1 in cultures of cumulus-oocyte complexes (COCs) or in co-cultures of OOX complexes failed to inhibit the ability of oocytes to enable cumulus expansion or inhibit progesterone production. Activin A had no effect on progesterone production by OOX complexes. In experiments using oocytes obtained from mice with deficient expression of GDF-9, OOX complexes cultured in the presence of heterozygous oocytes were capable of full expansion, whereas OOX complexes cultured with oocytes from GDF-9 null mice did not expand. Similarly, GDF-9 null oocytes failed to suppress FSH-induced progesterone production by OOX complexes. These results support the hypothesis that GDF-9 is the cumulus expansion enabling factor produced by mouse oocytes and that GDF-9 also inhibits cumulus progesterone production; however, the possibility remains that loss of GDF-9 may indirectly affect the ability of oocytes to produce the factors that regulate cumulus cell activity.

Elevated polyunsaturated fatty acids in blood serum obtained from children on the ketogenic diet.

The authors analyzed blood metabolites in nine children with epilepsy prior to starting the ketogenic diet (KD) and 3 to 4 weeks after KD therapy. Elevated beta-hydroxybutyrate and cortisol levels were observed in all children on the KD. Free fatty acids increased 2.2-fold on the KD, with significant elevations in most polyunsaturated fatty acids (PUFA; arachidonate increased 1.6- to 2.9-fold and docosahexaenoate increased 1.5- to 4.0-fold). The rise in total serum arachidonate correlated with improved seizure control. Elevated PUFA may represent a key anticonvulsant mechanism of the KD.

Positron emission tomography in the management of lymphomas.

Positron emission tomography is a functional imaging modality that capitalizes on biochemical changes within tumour cells to localize these changes within the body. As a functional imaging tool, unlike an anatomical imaging tool such as CT, it does not require enlargement of lymph nodes affected by disease but does require sufficient numbers of tumour cells to be present with altered biochemical function to visualize these disease sites. These changes are most commonly monitored using a glucose mimic fluorodeoxyglucose which is not only taken up into tumour cells but is trapped within these cells owing to alterations of the hexokinase and dephosphorylase enzymes. This review examines the current role of FDG PET imaging in patients with Hodgkins and Non-Hodgkins lymphoma and also speculates on future roles for this imaging modality.

Cerebral sinovenous thrombosis in children.

BACKGROUND: Cerebral sinovenous thrombosis in children is a serious disorder, and information is needed about its prevention and treatment. METHODS: The Canadian Pediatric Ischemic Stroke Registry was initiated in 1992 at the 16 pediatric tertiary care centers in Canada. Children (newborn to 18 years of age) with symptoms and radiographic confirmation of sinovenous thrombosis were included. RESULTS: During the first six years of the registry, 160 consecutive children with sinovenous thrombosis were enrolled, and the incidence of the disorder was 0.67 cases per 100,000 children per year. Neonates were most commonly affected. Fifty-eight percent of the children had seizures, 76 percent had diffuse neurologic signs, and 42 percent had focal neurologic signs. Risk factors included head and neck disorders (in 29 percent), acute systemic illnesses (in 54 percent), chronic systemic diseases (in 36 percent), and prothrombotic states (in 41 percent). Venous infarcts occurred in 41 percent of the children. Fifty-three percent of the children received antithrombotic agents. Neurologic deficits were present in 38 percent of the children, and 8 percent died; half the deaths were due to sinovenous thrombosis. Predictors of adverse neurologic outcomes were seizures at presentation and venous infarcts. CONCLUSIONS: Sinovenous thrombosis in children affects primarily neonates and results in neurologic impairment or death in approximately half the cases. The occurrence of venous infarcts or seizures portends a poor outcome.

Lack of expression of c-KIT in ovarian cancers is associated with poor prognosis.

The c-KIT protooncogene encodes a tyrosine kinase receptor, KIT, that is expressed in many normal and cancerous tissues. In this study, we have examined the expression of c-KIT and its ligand, stem cell factor (SCF), in human epithelial ovarian tumors, in normal ovaries and in cultured ovarian surface epithelium (OSE). Cultured cells, normal tissues and tumors were analyzed by Northern and Western blot analyses, reverse transcription-polymerase chain reaction and immunohistochemistry. Normal OSE expressed SCF, but not c-KIT; however, epithelial invaginations and inclusion cysts often expressed KIT protein. Of 15 benign ovarian tumors and tumors of low malignant potential, 87% expressed c-KIT, and 92% of these co-expressed SCF, suggesting the possibility of autocrine growth regulation. Of 35 malignant ovarian cancers, 71% expressed c-KIT (92% co-expressed SCF), with a trend for decreased c-KIT expression in advanced stage disease. Of 34 patients with malignant tumors for whom follow-up information was available (median follow-up time of 24 months), 9 had tumors that did not express c-KIT, 8 (89%) of whom have died and the remaining 1 has recurrent disease. Of the 25 patients with tumors expressing c-KIT, 56% are still alive. Eight of the patients have no evidence of disease and all had KIT-expressing tumors. Statistical analysis indicated that patients whose tumors did not express c-KIT had a significantly shorter (p < 0.05) disease-free survival time than patients who had KIT-expressing tumors. Our results suggest that c-KIT may play a role in early ovarian tumorigenesis, and that loss of c-KIT expression is associated with poor prognosis.

Mouse oocytes regulate granulosa cell steroidogenesis throughout follicular development.

Mouse oocytes secrete a factor(s) that inhibits progesterone and enhances estradiol production by granulosa cells. This study determined the ability of mouse oocytes to secrete this steroid-regulating factor during oocyte growth and the ability of granulosa cells to respond to the factor during follicular development. Oocyte-granulosa cell complexes from preantral and antral follicles were oocytectomized (OOX; oocytes microsurgically removed) and cultured for up to 48 h with FSH (150 ng/ml) and testosterone (500 nM). At all stages of development examined, OOX complexes produced more progesterone than did intact complexes, from 1.45-fold for early growing follicles to 23-fold for complexes from antral follicles. Significant estradiol production was restricted to intact complexes from late antral follicles. Progesterone accumulation by OOX complexes cocultured with oocytes was inhibited by all stages of oocytes examined, with maximal inhibition by fully grown oocytes. Ovulated complexes produced large quantities of progesterone, even though oocytes secreted progesterone-inhibitory factor, because of a desensitization of cumulus cells to the factor during their terminal differentiation. Even in the presence of abundant pregnenolone, OOX complexes showed reduced ability to produce and/or accumulate progesterone in the presence of oocytes, suggesting that the oocyte-secreted factor, either directly or indirectly, regulates the activity of 3beta-hydroxysteroid dehydrogenase and/or progesterone metabolism. These results demonstrate that oocytes secrete a factor with steroid-regulating activity in increasing amounts and/or potency during follicular development, but responsiveness of cumulus cells to this factor declines during luteinization.

Molecular cloning, structure, and expression of a testicular follitropin receptor with selective alteration in the carboxy terminus that affects signaling function.

During the molecular cloning of the ovine testicular follicle-stimulating (FSH) receptor that couples to the Gs-type effector systems, we discovered novel cDNA clones that were highly homologous. Some of these clones contained an insert of 1,584 bp, which consisted of a divergent 3' region spliced with a 5' region that was identical to nucleotides 724-1,924, forming part of the 9th and 10th exons, of the coding region of the ovine FSH receptor gene. The prominence of alternately spliced clone, which suggested important functional implications, prompted this detailed investigation. Screening of the library by polymerase chain reaction and Northern analysis of testicular messenger RNA with a specific ribo-probe directed to the divergent 3' region of this transcript suggested existence of a full-length transcript of roughly 2.4 kb size. The cDNA was assembled and characterized for its structure. The predicted full-length sequence consisting of nucleotides -121-1,924 of the ovine FSH receptor and the novel 3' region (nucleotides 1,925-2,307) encoded a protein of 670 amino acids containing the entire extracellular and transmembrane domains of the ovine FSH receptor. However, a frame-shift in the coding sequence at the point of divergence resulted in a shorter (40 residues vs. 65 for ovine FSH receptor) C-terminus with three cysteine residues and a reduced number of potential phosphorylation sites. Two of the cysteine residues were adjacent and are apparently potential double palmitoylation sites compared to the single site present in the Gs coupled ovine FSH receptor. Stable expression of this novel transcript in human embryonic kidney (HEK 293) cells revealed the complete absence of cyclic AMP inducible functions, but presence of specific hormone binding activity on plasma membranes and prominent cell surface immunostaining by antireceptor antiserum. There was no alteration in hormone binding specificity because the structurally analogous luteinizing hormone (LH) did not bind to the receptor. The loss of cyclic AMP stimulation in the transfected cells was completely opposite to the properties of the cells expressing the active wild-type receptor. When cells expressing active receptors were cotransfected with the altered FSH receptor cDNA, hormone action was inhibited, suggesting that it could be functioning as a dominant negative receptor. The existence of this ovine FSH receptor with an altered carboxyl terminus predicts the utilization of an alternative splicing mechanism for regulation of receptor expression, signalling and gonadal function. Our study reveals that the modular structure of the FSH receptor gene generates motifs that allows coupling to different effectors. This could become a common feature for all glycoprotein hormone receptors.

Interactions between the oocyte and cumulus cells in the ovary of the B6.Y(TIR) sex-reversed female mouse.

The XY (B6.Y(TIR)) sex-reversed female mouse is infertile, primarily because of the early death of its embryos. We have previously determined that the XY oocyte itself, not the surrounding somatic cells, is responsible for its failure in postfertilization development. In the present study, we assessed the ability of the XY oocyte to regulate granulosa cell differentiation and functions. Oocyte-cumulus complexes (OCC) were isolated from antral follicles and were cultured in the presence of FSH and testosterone. Microsurgical removal of oocytes prevented cumulus cell expansion and suppressed estradiol production while it promoted progesterone production. Coculture with denuded oocytes from either XX or XY ovaries restored cumulus expansion and the endocrine profile observed in intact OCC. Morphology of oocytes and OCC in the preantral and antral follicles in situ as well as after isolation was compared for XX and XY ovaries. The average area of XY oocytes was smaller by 20% only at the preantral stage, whereas the zona pellucida layer was thinner by 20% at all stages. Furthermore, the XY oocyte was found to be attached to fewer cumulus cells (60% of XX control) in antral follicles and isolated OCC. In conclusion, the XY oocyte develops the normal ability of regulating granulosa cell differentiation despite its inferiority with respect to some morphometric parameters when compared to the XX oocyte.

Ontogeny of FSH receptor messenger ribonucleic acid transcripts in relation to FSH secretion and testicular function in sheep.

The role of alternative splicing of the FSH receptor gene in the generation of FSH receptor proteins and testicular function remains an enigma. To address this issue, this investigation was conducted to determine variations in the expression of alternate FSH receptor mRNA transcripts in relation to changes in FSH release, hormone binding activity and testicular function during pubertal development of ram lambs from two genotypes of sheep (Romanov and a cross between Booroola x DLS) with different sexual precocity. Serum 17 beta-estradiol and testosterone concentrations were used as indices of Sertoli cell and testicular function. The results indicated that increases in Sertoli cell and testicular function normally seen during pubertal development are accompanied by age-dependent reductions in concentration of functional FSH receptors, as determined by binding of iodinated FSH to testicular membrane preparations. During the course of these changes, FSH release was either maintained at a steady level in Romanov lambs or it was gradually reduced in the Booroola x DLS cross, thus indicating that the testis had become more responsive to hormonal signal. This acquisition of heightened sensitivity was also associated with contrasting changes in the level of expression of FSH receptor mRNA transcripts. For both geno-types of sheep, 5 distinct species of mRNA transcripts of approximately 1.1, 1.5, 2.0, 2.5 and 6.5 kb were highly expressed from 11 to 22 weeks of age. Amongst these transcripts, the 1.1 kb molecular species was the most abundant. Specific probing for a previously cloned transcript called 151A1 representing the first 4 exons of the FSH receptor gene revealed a paradoxical increase in the level of expression from 11 weeks up to a maximum at 18-22 weeks of age for both genotypes. Collectively, the results indicated that contrasting changes in the production of specific alternatively spliced mRNA transcripts may mediate changes in FSH receptor expression which apparently accounts for the augmentation in sensitivity and function of the testis during pubertal development. Furthermore, the data provide the first important indication that the novel truncated transcript (151A1), which predictably encodes a soluble protein of either intra- or extracellular fate, could be physiologically relevant.

Neutrophil function in vitro: diapedesis and phagocytosis.

The function of neutrophils within the mammary gland was modeled in vitro to include diapedesis and phagocytosis. The bovine mammary cell line, MAC-T3, provided a mammary epithelial monolayer for use as a biologically meaningful barrier to neutrophil diapedesis. Features included characteristic transepithelial resistance, tight junctional complexes, and polarity. Continuous readings of transepithelial resistance indicated a stable resistance over several hours. Staphylococcus aureus, at concentrations of 1 x 10(7) and 2 x 10(9) cfu/ml, did not appear to have any deleterious effects on monolayer integrity over short-term (1 to 2 h) exposure. Neither resting nor challenged neutrophils caused short-term damage to the monolayer. Transepithelial resistance of the monolayers remained unchanged even as neutrophils were actively migrating through the monolayer. Further work using the MAC-T3 cell line and electrical resistance to assess cell monolayer integrity could provide much insight into the mechanisms underlying degeneration of mammary epithelial cells. The ability of neutrophils to phagocytose foreign particles is important for protection of the mammary gland. Neutrophils from proven bulls varied in their rate and capacity of phagocytosis. Correlations between neutrophil function and production traits were negative and small. In vitro analysis of neutrophil function provides another tool for the study of natural mastitis resistance.

The kinetics of tear fluid under the lower lid.

A very small drop of fluorescein solution was placed at the bottom of the lower fornix in human volunteers and its appearance in the tear film was measured. This was quite variable, but its appearance time averaged about 4 min and the peak of fluorescence 8 min. The time was shortened by blinking. The appearance time was too fast to be accounted for by simple diffusion in an unmixed tear fluid. Under normal circumstances, the release of the dye from the fornix is faster than its loss from the conjunctival sac, so that it does not seem to be a controlling factor in this loss.

Loss of fluorescein across the conjunctiva.

The rate of disappearance from the tear film of fluorescein and rhodamine dextran instilled together into the human eye was compared. In many cases fluorescein disappeared more rapidly, which was attributed to its penetration across the conjunctival surface. A corresponding mean fluorescein permeability across this surface of 2.5 x 10(-5) cm min-1 was calculated. This route of loss of fluorescein from the tears leads to an average overestimate of tear turnover of 25%.

Accessory nerve palsy: a review of 23 cases.

In a series of 23 patients, the commonest cause of accessory nerve palsy was surgical trauma at the time of lymph node biopsy. The less common causes were penetrating or blunt trauma and a few were of spontaneous onset. There was involvement of adjacent motor sensory nerves in about half of the patients. The prognosis was better following blunt trauma, stretch injuries and after a spontaneous onset. The anatomical relationships of the accessory nerve and aspects of the clinical picture and management are discussed.

Private hospitals and medical ethics.

The majority of hospitals in the United Kingdom are public authority hospitals administered according to the National Health Service Act 1977. However, there exist throughout the country a variety of independent hospitals run either as charities or for commercial gain. Elizabeth Macdonald examines the private hospitals' duty of care and the ethical basis from which it stems. She suggests mechanisms to monitor and support ethical standards in private hospitals.