Ahch, the mouse homologue of DAX1: cloning, characterization and synteny with GyK, the glycerol kinase locus

We cloned the murine full-length cDNA encoding Ahch, the mouse homologue of DAX1 (DSS-AHC Region on Human X Chromosome, Gene1) which is the gene responsible for human X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HH). Sequence analysis revealed that the murine and human cDNAs have 65% aa identity and 75% aa similarity overall. The cysteine residues in the putative DNA binding domain, which may interact with Zn2+ ions to form zinc fingers, are 100% conserved between the two species, indicating that the novel zinc-finger structures in DAX1 may be functional. In addition, mouse interspecific backcrosses show that the Ahch gene is closely linked to the glycerol kinase locus, GyK, on the mouse X chromosome, indicating that the order of the loci is conserved in this syntenic region between mouse and human.     

The dipsogen angiotensin II does not stimulate ethanol intake in mice

The Banff classification of acute rejection is based on histologic grades and scores for borderline changes, glomerular, vascular, interstitial and tubular lesions. We reviewed 56 episodes of acute rejection occurring in 44 kidney allograft recipients (30 cadaveric and 14 living donor transplants), comparing Banff classification to degree of reversibility of rejection. Rejection reversal was defined as complete if serum creatinine returned < or = 25% of baseline, partial if creatinine was > 25% to < 75% of baseline, and irreversible if creatinine was > or = 75% of baseline or graft loss occurred. Eight biopsies were classified as borderline (SUM score 1.6 +/- 0.5), 14 grade I (SUM score 3.3 +/- 0.4), 19 grade II (SUM score 4.2 +/- 0.3), and 15 grade III (SUM score 8.5 +/- 0.4). SUM distinguished borderline and grade III rejections, but not grades I and II. Clinically, grade and SUM score correlated with rejection reversal. Complete reversal of rejection occurred in 93% of patients with grade I rejection, while 47% of patients with grade III had irreversible rejection. The mean SUM for complete reversal was 3.9 +/- 0.34 and was different from SUM of partial (6.0 +/- 0.86) and irreversible (8.5 +/- 0.93), P < 0.006. Meanwhile, vascular scores were similar for rejections with complete (0.9 +/- 0.2) or partial (1.0 +/- 0.4) reversal, but significantly higher in those with irreversible rejection (3.0 +/- 0.4, P < 0.000). Likewise, mean scores for tubulitis and interstitial inflammation were significantly higher for irreversible rejection. Resolution of rejection by steroids was correlated to low vascular score (steroid sensitive 0.65 +/- 0.25 vs. steroid resistant 1.42 +/- 0.18, P < 0.01), and low SUM score (steroid sensitive 3.7 +/- 0.5 vs. steroid resistant 5.22 +/- 0.43, P < 0.04). Neither scores for tubulitis nor interstitial cellular inflammation were predictive of steroid sensitivity. These data demonstrate that Banff scoring has clinical relevance in predicting rejection reversal and has implications to first-line therapy of rejection episodes.     

Centromere-linkage analysis and consolidation of the zebrafish genetic map

The ease of isolating mutations in zebrafish will contribute to an understanding of a variety of processes common to all vertebrates. To facilitate genetic analysis of such mutations, we have identified DNA polymorphisms closely linked to each of the 25 centromeres of zebrafish, placed centromeres on the linkage map, increased the number of mapped PCR-based markers to 652, and consolidated the number of linkage groups to the number of chromosomes. This work makes possible centromere-linkage analysis, a novel, rapid method to assign mutations to a specific linkage group using half-tetrads.     

A chromatic-cancellation property of human pupillary responses

The pupil exhibits a response property somewhat analogous to perceptual red-green cancellation. Across a limited range of flash intensities near threshold, pupillary constrictions evoked by red flashes can be reduced, if not nulled, by the simultaneous addition of a green flash. The percentage of trials on which a stimulus-evoked response can be correctly discriminated from noise also falls to chance level as a green flash is added to the red flash. In terms of the quanta absorbed by L and M cones, the cancellation can be modelled as a function of magnitude of 0.65*L-M.     

Association between hyperadrenocorticism and development of calcium-containing uroliths in dogs with urolithiasis

OBJECTIVE: To determine, among dogs with urolithiasis, whether dogs that had hyperadrenocorticism would be more likely to have calcium-containing uroliths than would dogs that did not have clinical evidence of hyperadrenocorticism. DESIGN: Retrospective case-control study. ANIMALS: 20 dogs that had urolithiasis and hyperadrenocorticism and 42 breed-matched dogs that had urolithiasis but did not have clinical evidence of hyper-adrenocorticism. PROCEDURE: Signalment, urolith composition, results of bacterial culture of urine, and results of adrenal axis tests were recorded. A multivariate logistic regression model was created, including terms for age, sex, and hyperadrenocorticism. The outcome variable was presence or absence of calcium-containing uroliths. RESULTS: Among dogs with urolithiasis, those that had hyperadrenocorticism were 10 times as likely to have calcium-containing uroliths as were dogs that did not have clinical evidence of hyperadrenocorticism (odds ratio, 10.5; 95% confidence interval, 1.5 to 23.4). Neutered and sexually intact females were less likely to have calcium-containing uroliths than were neutered males (odds ratios, 0.041 [95% confidence interval, 0.0057 to 0.29] and 0.024 [95% confidence interval, 0.0012 to 0.51, respectively). CLINICAL IMPLICATIONS: Prompt diagnosis and treatment of hyperadrenocorticism may decrease prevalence of calcium-containing uroliths in dogs.     

Ultrasound screening for deep venous thrombosis after total knee arthroplasty. 2-year reassessment

The efficacy of ultrasound compared with ascending venography for the detection of deep venous thrombosis immediately after total knee arthroplasty was assessed after a 2-year interval. One hundred thirty-seven patients were eligible for the study; however, 31 patients received only one of the screening methods and a color Doppler examination was inconclusive in six patients. Therefore, 100 patients had a Doppler examination and a venogram. Overall, the sensitivity of ultrasound was 85%, the specificity 97%, the positive predictive value 85%, the negative predictive value 97%, and the accuracy 95%. The sensitivity in the calf was 83%, in the popliteal vein 86%, and in the femoral vein 100%. Two years ago, the initial assessment of ultrasound for the detection of deep venous thrombosis after surgery in patients who had total joint arthroplasty revealed a 75% sensitivity, 99% specificity, 91% positive predictive value, 97% negative predictive value, and 97% accuracy. The sensitivity in the calf was 83%; the sensitivity in the popliteal vein was 40%; and the sensitivity in the femoral vein was 50%. After 2 years of using this screening test with one technician and one radiologist, an improvement with this noninvasive technique was shown. However, it was found that Doppler imaging is not as sensitive as venography for detecting calf thrombi. Any imaging technique should be validated by each institution to determine the validity of the instrument and the learning curve of the technician administering the examination.