Effect of Weight Gain and Subsequent Weight Loss on Glucose Tolerance and Insulin Response in Healthy Cats

The effects of weight gain and subsequent weight loss on glucose tolerance and insulin response were evaluated in 12 healthy cats. Intravenous glucose tolerance tests (IVGTT) were performed at entry into the study, after a significant gain of body weight induced by feeding palatable commercial cat food ad libitum, after a significant loss of body weight induced by feeding a poorly palatable purified diet to discourage eating and promote fasting, and after recovery from fasting when body weight had returned to pre-study values and cats were eating commercial foods. A complete physical examination with measurement of body weight was performed weekly, a CBC and serum biochemistry panel were evaluated at the time of each IVGTT, and a liver biopsy specimen obtained 2 to 4 days after each IVGTT was evaluated histologically for each cat. Mean serum glucose and insulin concentrations after glucose infusion and total amount of insulin secreted during the second 60 minutes and entire 120 minutes after glucose infusion were significantly (P > .05) increased after weight gain, as compared with baseline. At the end of weight loss, cats had hepatic lipidosis and serum biochemical abnormalities consistent with feline hepatic lipidosis. There was a significant (P > .05) increase in mean serum glucose concentration and t_1/2, and a significant (P > .05) decrease in mean serum insulin concentration and the glucose disappearance coefficient (K) after glucose infusion for measurements obtained after weight loss, compared with those obtained after weight gain and at baseline. Insulin peak response, insulino-genic index, and total amount of insulin secreted during the initial 10 minutes, 20 minutes, and 60 minutes after glucose infusion were decreased markedly (P > .05), compared with measurements obtained after weight gain and at baseline. In addition, the total amount of insulin secreted for 120 minutes after glucose infusion was decreased markedly (P > .05) in measurements obtained after weight loss, compared with those obtained after weight gain. At the end of recovery, all cats were voluntarily consuming food, serum biochemical abnormalities identified after weight loss had resolved, the number and size of lipid vacuoles in hepatocytes had decreased, and results of IVGTT were similar to those obtained at baseline. These findings confirmed the reversibility of obesity-induced insulin resistance in cats, and documented initial deterioration in glucose tolerance and insulin response to glucose infusion when weight loss was caused by severe restriction of caloric intake.     

Septic osteitis of the distal phalanx in foals: 22 cases (1995-2002)

OBJECTIVE: To determine the clinical characteristics and outcome of foals with septic osteitis of the distal phalanx. DESIGN: Retrospective case series. ANIMALS: 22 foals. PROCEDURES: Information obtained from medical records included signalment; clinical, laboratory, and radiographic findings; treatment method; and outcome. Foals included in the study had lameness referable to the foot, radiographic evidence of localized lysis or focal loss of bone density of the distal phalanx, and suppurative discharge or necrosis of the affected bone evident at surgery. Foals with a history or evidence of penetrating wounds or subsolar abscessation were excluded. RESULTS: Mean age of foals at initial evaluation was 40.8 days (range, 3 to 122 days). Twenty-one (95%) foals had lameness as the primary complaint. Lesions consistent with septic osteitis of the distal phalanx localized to specific areas of the bone on the basis of radiographic and surgical findings were located on the solar margin or toe (14/22 [64%]), extensor process (5/22 [23%]), and palmar or plantar process (3/22 [13%]). Hind limbs (18/26 [69%] affected limbs) were more frequently affected. Two foals had > 1 affected limb, 2 had additional sites of osteomyelitis, and 4 had concurrent septic arthritis. Surgical debridement and regional antimicrobial perfusion were performed during general anesthesia. Extensor process lesions were not debrided. Nineteen of 22 (86%) foals survived to be discharged from hospital, and 16 horses reached racing age. Eleven of 16 had race starts, of which 8 had official race starts and 3 had unofficial race starts. CONCLUSIONS AND CLINICAL RELEVANCE: Septic osteitis of the distal phalanx should be considered as a source of lameness in foals with signs referable to the foot and does not necessarily preclude a career in racing. Although infection may occur secondary to bacterial penetration of the hoof or sole, the distal phalanx should also be considered as a potential site for hematogenous septic arthritis or osteomyelitis in foals.     

Development of a SNLP marker from the Pi-ta blast resistance gene by tri-primer PCR

The Pi-ta gene from indica introgressed into japonica rice has been used to control the blast disease caused by the fungal pathogen Magnaporthe grisea (Herbert) Barr. (anamorph Pyricularia oryzae Cav.) worldwide. A single nucleotide length polymorphism (SNLP) was identified at the intron region of the Pi-ta gene to develop a codominant Pi-ta gene marker suitable for genotyping with an automated machine. The DNA primer specific to the resistant Pi-taallele was labeled with blue dye (FAM, 6-carboxyfluorescein) as a forward primer, the DNA primer specific to the susceptible pi-ta allele was labeled with green dye (HEX, 4,7,2′,4′,5′,7′-hexachloro-6-carboxyfluorescein) as another forward primer and the DNA primer identical to both Pi-ta/pi-ta alleles was unlabeled as the reverse primer for polymerase chain reaction (PCR). Using these three primers, a 181-bp blue peak in homozygous resistant and a green peak of 182–183 bp in homozygous susceptible, and both peaks in heterozygous plants were produced by PCR. The utility of marker was verified using a segregating F₂ population, inbred cultivated lines, dominant markers and pathogenicity testing. A codominant Pi-ta marker was thus developed for effective Pi-ta assisted selection for crop improvement. Using highly homologous competitive primers for allele detection by PCR can benefit the study of genome organization of the complex locus. This revised version was published online in August 2006 with corrections to the Cover Date.     

Congruity backcrossing as a means of creating genetic variability in self pollinated crops: seed morphology of Phaseolus vulgaris L. and P. acutifolius A. Gray hybrids

Summary Seeds of early generations of three reciprocal congruity-backcross (CBC) pedigrees, developed by backcrossing Phaseolus vulgaris-P. acutifolius hybrids to each of the parent species in alternate generations, exhibited a preponderance of traits (size, shape, color, and pattern) of the cytoplasmic parent. The large size of Red Cloud (V₁), the P. vulgaris parent common to all of the pedigrees, dominated pedigrees with V₁ as the cytoplasmic parent, while the small size and rounded or square shapes of the tepary parents, wild P. acutifolius var. acutifolius PI 263590 or G400445 (A₁₉), wild P. acutifolius var. latifolius PI 406622 (A₁₀), or cultivated P. acutifolius var. latifolius Serowi PI 319443 (A₉), were the majority phenotypes when P. acutifolius was the cytoplasmic parent. Continuing through the second cycle of CBC, that is the second backcross with each of the parent species or the fourth backcross, began an amelioration of the apparent cytoplasmic effect on gene expression, as reciprocal pedigrees became more alike, usually with intermediate expression of parental traits or the appearance of new traits. The large seed size of V₁ was recovered in hybrids with P. acutifolius cytoplasm and the kidney shape of V₁ became rare in hybrids with P. vulgaris cytoplasm. Although the tepary-bean parents represented two subspecies and both cultivated and wild P. acutifolius, the three sets of reciprocal-hybrid pedigrees with P. vulgaris Red Cloud are surprisingly similar. It may be that the exotic parent used to develop a CBC pedigree should be selected more for combining ability in the interspecific cross than for specific economic traits. While the number of generations (six or more) required to produce fertile, intermediate CBC hybrids (that did not require embryo rescue) may preclude routine use of this method by practical plant breeders, the crossability of advanced hybrids with both parental species and the amount of variability apparent in advanced-hybrids progenies suggests that CBC would be valuable for maintaining exotic germplasm in immediately useful forms.     

Development and Implementation of a Forest Nursery Accreditation Policy at a Local Level in Leyte, Philippines

Through a series of workshops with the stakeholders including nursery operators, tree farmers, staff of the Department of Environment and Natural Resources, local government units and the academe, a forestry seedling nursery accreditation policy was developed. The resulting policy was subsequently implemented by the municipal government of Palompon, Leyte. The accreditation policy encouraged nursery operators to follow smallholder-based best management practices for tree nurseries. Implementation of the nursery accreditation policy improved farmers’ knowledge and skills in the production of high quality seedlings, encouraged adoption of BMP for forest nurseries, provided additional source of income for the farmers, enabled members of the groups operating the communal nursery to forge closer relationship with each other, encouraged utilization of farmers’ free time in productive activities, developed farmers’ confidence in producing high quality planting materials, and gained for the farmers favourable attention from various organizations and groups. The Bennett’s hierarchy of project outcomes showed that the implementation of accreditation scheme achieved high levels of outcomes, indicating that it led to substantial improvements in the lives of the farmers.     

Rust-proofing wheat for a changing climate

This paper offers projections of potential effects of climate change on rusts of wheat and how we should factor in a changing climate when planning for the future management of these diseases. Even though the rusts of wheat have been extensively studied internationally, there is a paucity of information on the likely effects of a changing climate on the rusts and their influence on wheat production. Due to the lack of published empirical research we relied on the few published studies of other plant diseases, our own unpublished work and relevant information from the vast literature on rusts of wheat to prepare this overview. Three broad areas of potential risks from a changing climate were described: increased loss from wheat rusts, new rust pathotypes evolving faster and the reduced effectiveness of rust resistances. Increased biomass of wheat crops grown in the presence of elevated CO₂ concentrations and higher temperatures will increase the leaf area available for attack by the pathogen leading to increased inoculum production. If changed weather conditions were to accelerate the life cycle of a pathogen, the increased inoculum can lead to severe rust epidemics in many environments. Likewise should the effects of climate change result in more conducive conditions for rust development there will also be a corresponding increase in the rate of evolution of new pathotypes which could increase the rate of appearance of new virulences. The effectiveness of some rust resistance genes is influenced by temperature and crop development stage. Climate change may directly or indirectly influence the effectiveness of some resistance genes but this can not be ascertained due to a complete lack of knowledge. Since disease resistance breeding is a long term strategy it is important to determine if any of the important genes may become less effective due to climate change. Studies must be made to acquire new information on the rust disease triangle to increase the adaptive capacity of wheat under climate change. Leadership within the Borlaug Global Rust Initiative (BGRI) is needed to broker research on rust evolution and the durability of resistance under climate change.