Increased responses to the actions of fibroblast growth factor 21 on energy balance and body weight in a seasonal model of adiposity.

The present study aimed to investigate the actions of fibroblast growth factor 21 (FGF21) on energy balance in a natural model of relative fatness, the Siberian hamster. Hamsters were studied under long days (LD) to promote weight gain, or short days to induce weight loss, and treated with rhFGF21 (3 mg/kg/day) via s.c. minipumps for 14 days. On days 7-9, detailed assessments of ingestive behaviour, metabolic gas exchange and locomotor activity were made. FGF21 caused substantial (P < 0.0001) weight loss in the fat LD state but not in the lean SD state: at the end of the study, FGF21-treated hamsters in LD lost 18% of body weight compared to vehicle controls, which is comparable to the natural body weight loss observed in SD. Epididymal fat pads, a correlate of total carcass fat content, were reduced by 19% in FGF21 treated hamsters in LD, whereas no difference was found in SD. Body weight loss in LD was associated with a reduction in food intake (P < 0.001) and a decreased respiratory exchange ratio (P < 0.001), indicating increased fat oxidation. Treatment with FGF21 maintained the normal nocturnal increase in oxygen consumption and carbon dioxide production into the early light phase in hamsters in LD, indicating increased energy expenditure, although locomotor activity was unaffected. These data suggest a greater efficacy of FGF21 in hamsters in LD compared to those in SD, which is consistent with both the peripheral and possibly central actions of FGF21 with respect to promoting a lean phenotype. The observed differences in FGF21 sensitivity may relate to day length-induced changes in adipose tissue mass.

Infections of the subcutis and skin of dogs caused by rapidly growing mycobacteria.

Nine dogs with panniculitis due to rapidly growing mycobacteria (RGM) were examined over 17 years. Dogs were two to 15 years; five were male, four were female. All were obese or in good condition. Antecedent injury, typically a dog bite or vehicular trauma, could be identified in some patients, while one bitch had hyperadrenocorticism. Infections involved different locations, although the cervicothoracic region, dorsum or flank were most often affected. Patients were systemically well, apart from one dog with pyrexia and two with pain or lameness. Cytology demonstrated pyogranulomatous inflammation, but in only one case was it possible to see acid-fast bacilli (AFB) in smears. Histology demonstrated chronic active pyogranulomatous panniculitis and dermatitis; AFB could be detected in only four specimens. Culture of aspirates or resected tissues demonstrated RGM in all cases, comprising six Mycobacterium smegmatis group and three Mycobacterium fortuitum group isolates. Resection of infected tissues, perioperative injectable antimicrobials and long courses of oral antimicrobials chosen according to susceptibility data generally effected a cure, although some cases recurred.

Primary sequence and developmental expression pattern of mRNAs and protein for an alpha1 subunit of the sodium pump cloned from the neural plate of Xenopus laevis.

Expression of a catalytic alpha subunit of the sodium pump was followed in early Xenopus embryos for correlation with physiological experiments showing that the sodium pump controls cavity expansion and the differentiation of neurones from the neural plate. Two cDNAs (one full length, one partial) for alpha1 subunit isoforms were cloned from a neural plate stage Xenopus library and sequenced. Other isoforms were not detected. Temporal and spatial expression patterns for alpha1 subunit transcripts and protein revealed extensive developmental regulation. At all stages, cells involved in cavity generation (outer ectoderm and cells lining the archenteron) expressed alpha1, transcripts with protein confined to the lateral and basal membranes. Before gastrulation, transcript levels were low and predominantly in animal cells. During gastrulation, alpha1 mRNAs rose significantly. Transcripts and protein were down-regulated in future outer neural plate cells as the mesoderm invaginated. Protein appeared at the blastopore on apical surfaces of lip cells and apposing surfaces of invaginating cells, suggesting that the Na pump opposes entry of fluid. In early neurulae, alpha1 mRNAs rose sharply. Transcript expression remained low in outer neural plate cells and increased in the endoderm, and protein appeared in the notochord. In midneurulae, transcripts returned in outer neural plate cells. Protein expression appeared on basal surfaces of deep neural plate cells and the floor plate, matching physiological observations. After neural tube closure, transcripts were detected in all dorsal structures. Protein was retained in the notochord and floor plate, was eliminated from the outer layer of the neural tube, and appeared on ependymal cells. The results are discussed in relation to previous physiological observations.

Characterization of parvalbumin cDNA clones and gene expression in normal and dystrophic mice of strain 129 ReJ.

Parvalbumin is a calcium-binding protein found in fast-twitch skeletal muscles and selected cells in the brain. In several dystrophic mutants in the mouse, the parvalbumin content of skeletal muscles and brain is reduced and this deficiency appears to correlate with the inability of these mice to handle enhanced calcium uptake associated with the dystrophic process. In this study, two overlapping cDNA clones of 392 and 1268 base pairs were isolated from a mouse cDNA library in lambda gt11, characterized, and used as probes to study the involvement of the parvalbumin gene and its expression in various tissues of dystrophic mice of strain 129 ReJ. Southern blot analyses of restriction fragments of genomic DNA from normal and dystrophic mice indicate the same number and size of parvalbumin-specific gene fragments observed by other researchers, suggesting that the size of the Pva gene is the same in both normal and dystrophic mice of strain 129 ReJ. Northern blot analyses of total RNA from hind-limb muscles using cloned parvalbumin cDNA as probes revealed an abundant 800-nucleotide mRNA with lesser amounts of a 1000-nucleotide mRNA transcript in both normal and dystrophic mice of strain 129 ReJ. The amount of these mRNAs was reduced by 65-77% in dystrophic muscles preparations and was similar to the levels of beta-actin mRNA in these animals. These results suggest that parvalbumin gene expression is not down regulated in dystrophic mice of strain 129 ReJ.

Multiple large hyperplastic polyps of the colon coincident with adenocarcinoma.

Diminutive hyperplastic polyps are the most common non-neoplastic lesions of the colon. Typically, they are small (< 0.5 cm) sessile lesions, lack cellular atypia, and are found predominantly in the rectosigmoid region of the colon. Multiple large hyperplastic polyps (> 1 cm) are rare. Although the relationship between diminutive hyperplastic polyps and adenomatous polyps or carcinoma is controversial, even less data are available on the significance of large hyperplastic polyps. We report the case of a 56-yr-old man who was seen because of fatigue, anemia, and Hemoccult-positive stool. On air contrast barium enema study and colonoscopy, multiple polyps that were similar in appearance were found distributed symmetrically throughout the colon. However, histologic examination revealed 16 hyperplastic polyps 1-2 cm in size, multiple diminutive hyperplastic polyps, one adenomatous polyp, and one adenomatous polyp containing well-differentiated adenocarcinoma. Because multiple large hyperplastic polyps are rare, we suspect this entity may be distinct from diminutive hyperplastic polyps. In our patient, large hyperplastic polyps were distributed symmetrically throughout the colon and were associated with a synchronous carcinoma. Because large hyperplastic polyps may be coincident with adenomatous polyps and carcinoma of the colon, we recommend that patients found to have large hyperplastic polyps undergo removal of all polyps for histologic study.