Analysis of the cephalometric changes in the first 3 months after spring-assisted cranioplasty for scaphocephaly.

BACKGROUND: Spring-assisted cranioplasty (SAC) has become an accepted treatment for patients with sagittal craniosynostosis; however, the early effects of springs on skull dimensions have never been assessed with objective measurements in the literature. The present study evaluated the changes in skull dimensions and intracranial volume (ICV) during the first 3 months after SAC for sagittal synostosis. METHODS: Sixteen patients with sagittal synostosis underwent SAC. The cephalic index (CI) and the distance between the spring foot plates were chronologically measured until spring removal at 3 months. Pre- and post-treatment CT scans available for 6 patients were used to assess changes in head shape. Thirteen patients underwent objective aesthetic assessment using pre- and post-operative photographs. Statistical analysis was performed using the linear mixed model for chronological data, t-test statistics for normative data comparisons and Wilcoxon's signed rank test for non-parametric data. RESULTS: For scaphocephalic patients, pre-operative and post-operative CIs were 0.70 and 0.74 (p = 0.001), respectively. Cranial widening towards normative values was observed (p = 0.0005). A continuous expansion in the distance between the spring foot plates was observed over the treatment period. Frontal and occipital angles were not affected by SAC despite apparent clinical improvements in frontal bossing and occipital prominence. CT analysis demonstrated relative reduction in the anterior cranial volume (p = 0.01) and relative expansion of the superior occipital volume (p = 0.03). CONCLUSIONS: Spring expansion was most marked in the hours following spring insertion. The expansion rate reduced to the minimum by day 1 post-operatively. Clinical benefits of SAC resulted from an increase in the bi-temporal width that camouflaged the frontal bossing. Improvement in occipital prominence was due to superior occipital volume expansion, allowing the occiput to remodel to a more rounded shape.

Spatial and temporal variation in lead levels related to body condition in the Mississippi Valley population of Canada geese.

Concern over lead poisoning led to progressive prohibition of toxic shot to harvest waterfowl in the 1980's. Nevertheless, waterfowl remain susceptible to ingestion of lead shot because illegal use continues and spent shot persists in soil and wetland substrates. While mortality due to lead toxicosis has subsided, sublethal effects may still affect survival and reproduction. We measured liver lead levels and body condition in 732 Canada geese (Branta canadensis interior) during July 1984 to April 1989 in southern Illinois (USA), east-central Wisconsin (USA), and northern Ontario (Canada). Although we sampled only individuals that were visibly healthy, 55 of 732 (7.5%) geese had elevated liver lead levels (> 2 ppm). Lead levels of 46 (6.3%) geese indicated subclinical poisoning (2-6 ppm) and 9 (1.2%) geese had lead levels indicative of clinical poisoning (> 6 ppm). A greater proportion of juveniles (14.3%) had elevated lead levels than did adults (6.0%), but there was no difference between genders. Lead levels were highest in autumn and winter in southern Illinois, but were low during nesting and summer, despite legal use of lead shot in northern Ontario during our study. Lead poisoning (> or = 5% of the population) was still evident during all seasons in juveniles, and during autumn and winter in adults, 5 to 10 yr after toxic shot was banned from areas where we collected geese during migration and winter. Elevated lead levels did not affect total body mass, lipid reserves, or mineral levels of geese we collected. Protein levels also were unaffected below 10 ppm, but there was evidence of decline at higher concentrations. Thus, it seems unlikely that lead exposure currently affects survival or reproduction of Mississippi Valley Population (MVP) geese via body condition, although other sublethal effects cannot be discounted.

Hormonal regulation of spermatogenesis in the hypophysectomized rat: FSH maintenance of cellular viability during pubertal spermatogenesis.

The potential for follicle-stimulating hormone (FSH) to promote germ-cell survival and the cellular sites of FSH action were studied using a gonadally maturing (pubertal), hypophysectomized (Hx) rat model in which residual testosterone (T) activity was blocked by injections of an androgen-receptor antagonist, flutamide. Recombinant human FSH was given to androgen-deprived and androgen-blocked male rats at 27 days of age to determine maintenance of individual germ-cell types at 35 days of age. Follicle-stimulating hormone significantly increased testis weights and tubular diameters as compared with Hx and Hx-flutamide controls, although testis weights in FSH-treated animals were significantly lower than in pituitary-intact animals. Morphometric assays to determine ratios of germ cells to Sertoli cells and to determine the number of germ cells present per hour of development showed that the population of type A spermatogonia in the early stages of the cycle was not responsive to FSH. Follicle-stimulating hormone had a marked ability to maintain cell viability in the rapid, successive divisions that begin in the latter part of the cycle and that continue through the next cycle (i.e., from type A1 to A4 and from intermediate spermatogonia to type B spermatogonia to preleptotene spermatocytes to leptotene/zygotene spermatocytes to young pachytene spermatocytes). The data also suggest T responsiveness of these cell types since the Hx-FSH-flutamide group showed lower cell viability at the aforementioned steps when compared with the Hx-FSH group. Too few cell types were present at subsequent phases of spermatogenesis to allow a sensitive determination of FSH activity in the maintenance of cell viability. The data show the potential of FSH in the absence or relative absence of T activity to maintain cell viability. These data support the concept of overlapping and synergistic (or additive) effects of T and FSH in the immature rat and identify the cellular sites of FSH action.

Hormonal regulation of spermatogenesis in the hypophysectomized rat: quantitation of germ-cell population and effect of elimination of residual testosterone after long-term hypophysectomy.

Spermatogenesis continues after long-term hypophysectomy (Hx), but massive cell degeneration prevents seminiferous tubules from attaining the full complement of cells. One objective of this study was to determine the vulnerable sites for completion of spermatogenesis in long-term Hx rats. It is now known that Leydig cells continue to secrete small amounts of androgen after Hx. A second objective was to determine the cellular sites that are maintained by residual androgen secreted by Leydig cells post-Hx. Two groups of adult animals were utilized. Both groups were Hx for 36 days, but one group of rats received the androgen antagonist flutamide during the 26th through the 36th day of Hx (10 days). Germ-cell numbers were quantified using a method that allowed their expression as numbers of cells present per hour of development. In the long-term Hx rat, the germ-cell population increased to preleptotene, but the divisions that led to preleptotene were inefficient due to cell degeneration. Subsequent to preleptotene, there was a gradual loss in cells such that there were few germ cells remaining by steps 9-13. Flutamide given to Hx rats did not result in a significant difference in the numbers of intermediate and type B spermatogonia or significant differences in progenitor cells. A significant and major depression of cell numbers in Hx-flutamide-treated rats occurred in the cell division of type B spermatogonia to form preleptotene spermatocytes. There was a less dramatic, although significant, depression of cell numbers in Hx-flutamide-treated animals that occurred from preleptotene until late pachytene as well as an increased loss of round spermatids at midcycle (step 5-6). These data demonstrate that cell loss after long-term Hx occurs at numerous phases of spermatogenesis. The data also demonstrate that the presence of residual androgen action after long-term Hx results in enhanced germ-cell survival. Although the major blockage in cell viability occurs at midcycle steps in the long-term Hx rat, there are several other hormone-sensitive phases of spermatogenesis.

Hormonal regulation of spermatogenesis in the hypophysectomized rat: cell viability after hormonal replacement in adults after intermediate periods of hypophysectomy.

A quantitative analysis of germ-cell populations in normal, hypophysectomized (Hx), and Hx-hormone-treated animals was undertaken during periods of regression that were characterized as intermediate, between short-term and long-term regression of the testis. Twenty-one groups of adult rats were administered either follicle-stimulating hormone (FSH), growth hormone, thyroid-stimulating hormone (TSH), or testosterone (T) in various doses and combinations. The dosage of T administered was less than that expected to achieve maximum testis weight. Flutamide and Casodex were used to compete with androgen binding to receptors in Hx animals, as it is known that small amounts of androgen are secreted in the absence of pituitary stimulation. Follicle-stimulating hormone, T, and TSH all significantly maintained testis weight as compared with Hx controls, although FSH and T, singly or in combination, were the most effective. Contamination of the TSH preparation with trace amounts of FSH was apparently responsible for the slight maintenance of testis weight. A novel assay for determination of the numbers of viable germ cells was used in a subset of these groups to determine the cellular sites of FSH and T action. Numbers of type A spermatogonia were lowered after Hx and were maintained by either FSH or T or a combination of these hormones. Other phases of germ-cell development most susceptible to FSH and/or T were the successive conversions of type A spermatogonia to intermediate spermatogonia, intermediate spermatogonia to type B spermatogonia, preleptotene spermatocytes to pachytene spermatocytes, and early pachytene spermatocytes to intermediate maturity pachytene spermatocytes during early and midcycle phases of pachytene spermatocyte development. Germ-cell loss during meiosis and virtually every phase of spermatid development was largely prevented by FSH or T or a combination of these hormones. Thus, in testes in advanced stages of regression, both FSH and T were capable of preventing cell loss, suggesting that both hormones can affect the survival of the same cell type. The present study demonstrated that FSH can partially compensate for lowered T levels. The combined administration of FSH and T was more effective in preventing overall cell degeneration than either hormone alone. Unlike the initial phase of spermatogenesis, in which there is a largely midcycle loss of germ cells due to Hx, the loss of cells during testis regression is more widespread and impacts several cell types in more than one stage of the spermatogenic cycle.

A new selective enrichment procedure for isolating Pasteurella multocida from avian and environmental samples.

A selective enrichment procedure, using two new selective media, was developed to isolate Pasteurella multocida from wild birds and environmental samples. These media were developed by testing 15 selective agents with six isolates of P. multocida from wild avian origin and seven other bacteria representing genera frequently found in environmental and avian samples. The resulting media--Pasteurella multocida selective enrichment broth and Pasteurella multocida selective agar--consisted of a blood agar medium at pH 10 containing gentamicin, potassium tellurite, and amphotericin B. Media were tested to determine: 1) selectivity when attempting isolation from pond water and avian carcasses, 2) sensitivity for detection of low numbers of P. multocida from pure and mixed cultures, 3) host range specificity of the media, and 4) performance compared with standard blood agar. With the new selective enrichment procedure, P. multocida was isolated from inoculated (60 organisms/ml) pond water 84% of the time, whereas when standard blood agar was used, the recovery rate was 0%.

Prevalence of spindle cell sarcomas among wild Canada geese from southern Illinois.

Over a 6-yr period, two cases of neoplastic disease were diagnosed among 1,272 wild Canada geese (Branta canadensis interior) collected in Illinois (USA), Wisconsin (USA), and Ontario, Canada. One juvenile goose of each sex was involved. In both cases > 35 discrete masses were observed subdermally, intramuscularly, and within the body cavity. The tumors, diagnosed as spindle cell sarcomas, are among the most commonly observed neoplasms in free-living North American waterfowl. Based on our data, we suggest that these neoplasms occur with extremely low prevalence (0.002%) in free-living Canada geese.

From educational philosophy to educational practice: fidelity and the curriculum in context.

As part of a higher degree on research methods, exploratory work was undertaken concerning educational philosophy and educational practice using an ethnographic approach. This author discusses, using this exploratory work, the difficulties of attempting fidelity to an educational philosophy, through curriculum practice. Schools of nursing are increasingly adopting a rational approach to education, without considering the wider social context within which education occurs. The attempt to establish and pursue a single philosophy, ignores the plurality of ideological commitments held by nurse teachers. Further research is proposed using naturalistic methods in order to understand the processes of interpretation and implementation of educational philosophy.

Teacher behaviour: a determinant of student self esteem.

This small scale piece of research was undertaken to establish whether there existed a relationship between teacher behaviour and the reported self esteem inventories of four students. Using a low inference category system for rating teacher behaviour the researcher's behaviour was observed and categorised by an independent rater. The students were asked to complete Coopersmith's (1967) modified self-esteem inventory both before and after each teaching session. Following the first teaching session, the remaining two, in terms of teacher behaviour, were experimentally manipulated. A repeated measures design was utilised, in order to reduce confounding variables in subjects. Results have been analysed using the 'T' test to calculate statistical significance between 'Pre' and 'Post' inventory scores of students. The paper clearly shows the need for the researcher to remain sensitive to experimental design when undertaking small scale research.

Reversal of streptozotocin-induced diabetes in rats by intraperitoneal implantation of encapsulated neonatal rabbit pancreatic tissue.

Implants of rabbit neonatal pancreas, encased in 'Nucleopore' chambers (0.4 micrometer) reversed streptozotocin-induced diabetes in the rat. Blood-glucose, plasma-insulin, and oral glucose-tolerance test returned to normal. An isolated, perfused, streptozotocin-treated pancreas removed from a diabetic animal did not secrete insulin and removal of implants after 6 weeks from six animals caused all animals to die in hyperglycaemia within 8 days. This shows that the implant did not lead to the re-establishment of endogenous pancreatic function. Implanted diced neonatal pancreas in three chambers removed after 6 weeks secreted glucagon, insulin, and pancreatic polypeptide in vitro. No rejection reactions were seen. Rabbit neonatal pancreatic implants may thus be feasible therapy in insulin-requiring diabetic patients. Implants of other non-syngeneic endocrine cells--i.e., pituitary, thyroid, and ovary--may be useful in other hypoendocrine syndromes.

The ability of pancreatic polypeptides (APP and BPP) to return to normal the hyperglycaemia, hyperinsulinaemia and weight gain of New Zealand obese mice.

Intraperitoneal injections of avian pancreatic polypeptide (APP) and bovine pancreatic polypeptide (BPP) are capable of returning to normal the hyperinsulinaemia, hyperglycaemia and weight gain of New Zealand obese mice. The lag glucose tolerance also becomes indistinguishable from normal. The mechanism whereby these polypeptides cause reversion is not known. Reversion can also be brought about by the intraperitoneal implantation of islets from white mice into New Zealand obese animals. The implanted islets secrete mouse pancreatic polypeptide. We conclude that the New Zealand obese syndrome arises from a genetic lack of mouse pancreatic polypeptide. We suggest that in humans a lack of pancreatic polypeptide might manifest as a syndrome analogous to that found in New Zealand obese mice.