Clinical and pathological characterization of an osteoma in a barred owl

Osteomas are rare in birds. An osteoma of the left proximal radius was diagnosed in an adult barred owl based on gross, radiographic, and pathologic findings.     

Regional mapping of the gene encoding dihydroorotate dehydrogenase,an enzyme involved in UMP synthesis,electron transport,and superoxide generation,to human chromosome region 16q22

De novo UMP synthesis is a critical metabolic pathway for nucleic acid synthesis and for a variety of metabolic pathways. The pathway is a target for many widely used cancer chemotherapy agents, several of which are pyrimidine analogs. Humans and cattle have been described with mutations in UMP synthesis that lead to serious inborn errors of metabolism. Dihydroorotate dehydrogenase (EC 1.3.3.1) (DHODH) carries out the fourth committed step in the pathway and may also be important for mitochondrial electron transport and oxygen radical metabolism. We report here that the gene encoding this enzyme in humans is located in the chromosomal region 16q22. With the mapping of DHODH, the mapping of all the steps of UMP synthesis is complete. All three genes involved map to different human chromosomes. This information is important in consideration of regulation of UMP synthesis in mammals, including humans.     

Neisseria meningitidis bacteremia in association with deficiency of the sixth component of complement.

The serum of a 26-year-old black man with a recent episode of meningococcemia complicated by meningitis and arthritis was found to lack hemolytic complement activity. The sixth component of complement was not detected by functional or immunochemical assays whereas other components were normal by hemolytic assay. His fresh acute-phase serum lacked complement-mediated bactericidal activity against the homologous strain of Neisseria meningitidis, but the addition of fresh normal serum or purified C6 restored bactericidal activity as well as hemolytic activity. The absence of C6 activity could not be accounted for on the basis of an inhibitor. Opsonization and chemotaxis functioned normally. Histocompatibility typing of family members did not demonstrate evidence for genetic linkage of C6 deficiency with the major histocompatibility loci. This report represents the first published case of C6 deficiency associated with bacteremic Neisseria infections in which antimeningococcal bactericidal antibodies have been definitively demonstrated against the homologous strain in the acute phase of the illness.     

External fixation of unstable pelvic ring fractures: comparative rigidity of some current frame configurations

The effectiveness of external fixation in the stabilisation of pelvic ring fractures was studied in a laboratory cadaveric series. Shearing displacements occurring at sacroiliac joint and symphysis pubis dislocation sites, due to simplified longitudinal loading of the sacrum in an Instron unit, were monitored using variable-impedence transducers. The rigidity of fixation was compared for the Slätis and the Bonnel single anterior frames, for coupled and uncoupled double anterior frames, and for combined anterior-plus-posterior fixation achieved with separate transfixation pin clusters, with through-and-through pin clusters, or with a posterior screw plate. The data showed that the use of posterior fixation provided greatly enhanced stabilisation compared to that achieved with anterior fixation alone. The complex double anterior frames performed only slightly better than did the simpler single anterior frames. In no case, however, was it possible to recover rigidity levels approaching those of the intact pelvis. The results suggest that the transfixation pin arrangement is the most important determinant of pelvic fixation stability, and that further investigation of posterior screw-plate fixation is warranted.     

Atlas of Hox gene expression in the developing kidney.

Hox genes often play important roles in segment identity determination and organogenesis. To better understand the roles of Hox genes during kidney development, we performed an extensive analysis of their expression patterns. Section in situ hybridizations were used to define the expression of 37 Hox genes at embryonic day (E) 12.5, E13.5, E15.5, and E17.5 of kidney development. Several interesting principles emerged. First, the concept of colinearity was preserved. Hox genes from the more 3' positions in clusters were more often expressed in the ureteric bud, which is derived from the anterior of the intermediate mesoderm. Second, Hox genes were expressed throughout the ureteric bud without any segment specificity. Third, in the different segments of the forming nephron we did observe overlapping domains of Hox gene expression, which initiated distally at the junction between the nephron and ureteric bud, and extended proximally variable distances. Finally, we observed that paralogous Hox genes often showed surprisingly diverse expression patterns. Indeed, contiguous genes on a single cluster more often showed similar expression patterns than paralogs. In summary, the resulting atlas of Hox gene expression provides a foundation for further study of the overlapping functions Hox genes in the developing kidney.     

Dual suppression with oral contraceptives and gonadotrophin releasing- hormone agonists improves in-vitro fertilization outcome in high responder patients

Certain patients have a tendency for high response to gonadotrophin therapy which is often not ameliorated with prior gonadotrophin- releasing hormone agonist (GnRHa) suppression. As a result, these patients are frequently cancelled and often experience ovarian hyperstimulation syndrome (OHSS) episodes during in-vitro fertilization (IVF)-embryo transfer cycles. Patients with polycystic ovarian syndrome (PCOS) have been noted to be particularly sensitive to exogenous gonadotrophin therapy. We have developed a protocol which is effective in improving IVF outcome in high responder patients, including those with PCOS. Oral contraceptive pills (OCP) are taken for 25 days followed by s.c. leuprolide acetate, 1 mg/day, which is overlapped with the final 5 days of oral contraceptive administration. Low-dose gonadotrophin stimulation is then initiated on the third day of withdrawal bleeding in the form of either human menopausal gonadotrophins or purified urinary follicle-stimulating hormone at a dosage of 150 IU/day. Over a 5 year period, we reviewed our experience utilizing this dual method of suppression in 99 cycles obtained in 73 high responder patients. There were only 13 cancellations prior to embryo transfer (13.1%). The clinical and ongoing pregnancy rates per initiated cycle were 46.5 and 40.4% respectively. Only eight patients experienced mild-moderate OHSS following treatment. For those patients who had undergone previous IVF-embryo transfer cycles at our centre, significant improvements were noted in oocyte fertilization rates, embryo implantation rates and clinical/ongoing pregnancy rates with this protocol. Hormonal analyses revealed that the chief mechanism may be through an improved luteinizing hormone/follicle-stimulating hormone ratio following dual suppression. An additional feature of this dual method of suppression is significantly lower serum androgen concentrations, particularly dehydroepiandrosterone sulphate.      

Thermal tolerance following artificially induced polycythaemia

Polycythaemia has been shown to improve physical performance, possibly due to increased arterial oxygen transport. Enhanced thermoregulatory function may also accompany this manipulation, since a greater proportion of the cardiac output becomes available for heat dissipation. We further examined this possibility in five trained men, who participated in three-phase heat stress trials (20 min rest, 20 min cycling at 30% peak power W_peak and 20 min at 45% W_peak at 38.3 (SEM 0.7)°C [relative humidity 41.4 (SEM 2.9)%]. Trials were performed during normocythaemia (control) and polycythaemia, obtained by reinfusion of autologous red blood cells and resulting in significant elevation of arterial oxygen transport. During the polycythaemic trials, the subjects demonstrated diminished thermal strain, as evidenced by a significant reduction in cardiac frequency (f _c: 12 beats · min^–1 lower throughout the test;P < 0.05), and reduced auditory canal temperatures (T _ae) during the latter 20-min phase (P < 0.05). Forearm sweat onset was more rapid (363.0 compared to 1083.0 s;P < 0.05), and forearm sweat rate (. _msw) sensitivity was elevated from 1.80 to 2.91 · mg · cm^–2 · min^–1 · °C^–1 (P < 0.05). Foreheadm _sw was depressed during the final 20 min, while forearmm _sw was greater during all test phases, averaging 0.94 and 1.20 mg · cm^–2 · min^–1, respectively, over the 60 min. Skin blood flows for the upper back, upper arm and forearm were reduced (P < 0.05). Polycythaemia enhanced thermoregulation, through an elevation in forearm sweat sensitivity and.m _sw, but not via increased cutaneous blood flow. These modifications occurred simultaneously with decreases inf _c andT _ae, resulting in greater thermal tolerance.     

Arthroscopic washout of the knee--a 5-year survival analysis

Arthroscopy and washout of the knee is commonly performed for early osteoarthritis. Very little information exists regarding long-term prognosis, especially in terms of avoidance of further surgery. Using a prospectively gathered database, 100 consecutive patients having knee arthroscopy with a finding of OA between 1991 and 1993 were identified and their outcome at 5 years ascertained. Ninety-nine patients with 100 arthroscoped knees were identified. Fifty-eight had isolated medial compartment disease and six had isolated lateral compartment disease. In 36, both compartments were affected. Eighteen knees had further major surgery during follow up; 11 had total knee replacement, four had high tibial osteotomy and three had unicondylar knee arthroplasty. Those requiring surgery were significantly older (62 cf. 53 years, P=0.008). Meniscectomy was not an important risk factor (chi2, P=0.67). The rate of knee survival without operation at 5 years was much lower in those aged over 60 years than in those younger (68% cf. 89%). (chi2, P=0.02). Only 18% of patients progress to major knee surgery within 5 years of arthroscopic washout for osteoarthritis. Age greater than 60 years worsens the prognosis considerably.