Large Variation In Age Research Articles

Treatment with 17beta-oestradiol does not influence age and weight at puberty in Bos indicus heifers.

The working hypothesis was that treatment of heifers with 17beta-oestradiol (E2) during specific periods of prepuberty would reduce the response of the hypothalamic-pituitary axis to E2 negative feedback and induce an earlier onset of puberty. The effects of chronic treatment with exogenous E2 administered at specific maturational phases on the age and weight at puberty were studied in 96 prepubertal Brahman (3/4-7/8 Bos indicus) heifers (187.0 +/- 3.3 days of age, mean +/- SEM), weighing 149.9 +/- 2.5 kg. Heifers were randomly assigned to one of six groups (n = 16 per group). Groups 2-6 received E2 implants (Compudose 200) for 90-day periods starting at 10, 13, 16, 19 and 22 months of age, while animals in group 1 remained untreated. Implants were placed subcutaneously at the base of the ear. Blood was collected for progesterone (P4) determination by radioimmunoassay (RIA) and the animals were weighed at monthly intervals from 6 to 15 months then weekly from 15 to 28 months of age. Puberty was defined by concentrations of P > 1 ng/ml in plasma and identification of a corpus luteum (CL) by transrectal ultrasonography (Aloka 210DX:7.5 MHZ probe). Treatment with exogenous E2 at any of the ages/treatment intervals evaluated in this study did not reduce age or weight at puberty (P > 0.7). The mean age and weight at puberty of control heifers was 735.3 +/- 19.7 days (range: 597-861) and 299.2 +/- 10.2 kg (range: 233-382), respectively, which is greater than the age and weight at puberty of 481 days and 246 kg, that was previously reported for B. indicus heifers [Post, T.B., Reich, M.M., 1980. Puberty in tropical breeds of heifers as monitored by plasmaprogesterone. Proceedings of the Australian Society of Animal Production 13, 61-62.]. The large variation in age and weight at puberty that was observed in the present study among heifers might indicate an individual animal effect to E2 treatment among some of the treated animals. The lengthy interval from birth to puberty observed in this study, as compared to other studies, reflects the effects of other factors such as genotype, environmental or nutritional influences on puberty.

A food-independent maturation threshold and size at maturity in Daphnia magna

Age and size at maturity are among the key traits of life-history evolution in Daphnia. Growth data from one clone of Daphnia magna show that there is a threshold size above which maturation is initiated. This threshold mechanism regulates body length at maturity at the cost of age at maturity. A model explains how the threshold accounts for large variation in age and size at maturity.

Carcinoma of the Breast Metastatic to the Skeleton

A review of 319 patients with breast carcinoma metastatic to the skeleton revealed a large variation in age at diagnosis, interval between diagnosis of primary disease and metastasis, and survival time with metastasis. The presence of bony metastasis only is a good prognostic sign, and the presence of neurologic defects without successful correction is a poor prognostic sign. Bone lesions are radiosensitive, and fractures usually heal with radiation. It is difficult to define impending fractures, but large lytic lesions, increased body weight, increased activity, and areas of high stress are factors that can be used to determine the risk of fracture. Femoral neck fractures should be treated by endoprostheses or total hip arthroplasty and femoral shaft fractures by appropriate internal fixation. In the present series humeral fractures were successfully managed conservatively, but it is possible that with a wider data base the advantages of immediate rigid fixation by internal fixation with methylmethacrylate cement would be more obvious. Use of methylmethacrylate should be restricted to patients with short-term survival expectancies and large defects. Most spinal metastases can be treated by radiation and orthoses, but an aggressive approach is indicated for patients with neurologic deficits. Laminectomy is indicated for lesions that produce posterior compression, anterior decompression for lesions producing anterior compression, and stabilization for alignment deformities or instability.

Pooled European series of hereditary peripheral neuropathies in infancy and childhood. A "correspondence work shop" report of the European Federation of Child Neurology Societies (EFCNS).

A European series of 287 cases of "pure" peripheral neuropathy, pooled from 14 neuropediatric centres, has been analysed retrospectively with particular emphasis on the hereditary motor and sensory neuropathies (HMSN) which comprised 241 of the patients. Due to incomplete information in many records it has only been possible to make a crude analysis of the problems of diagnosis and classification. More than half of the HMSN series conform to the diagnosis of HMSN I (charcot-Marie-Tooth-Roussy-Levy disease), A relatively homogeneous group but with large variations in age of onset and severity of disease between individuals in the same family. In five of the 147 cases the onset was at or before birth. An overdiagnosis of HMSN III (Déjérine-Sottas' disease) was considered probable due partly to an unawareness of the high frequency of subclinical carriers among parents in families with HMSN I. Cases with axonal types of polyneuropathy, appearing sporadically or with suspected autosomal dominant (HMSN II) or recessive inheritance, occurred with unexpected frequency in children. This group of 60 pooled European cases was considered worthy of a particularly thorough follow-up and further investigation in order to achieve a better delineation between different subtypes. Cases with an onset before birth or very early in infancy (20 cases) comprised a heterogeneous group with some special subtypes. Surprisingly enough, no less than 5 of the 20 cases represented HMSN I. Cerebrospinal fluid protein levels were not found to be useful for differentiating various types of HMSN. Elevated levels were revealed in about half of the examined cases of HMSN I and in 75% of cases of HMSN III, the levels of increase showing a marked overlap. In nearly all of the axonal cases investigated the CSF protein was normal.

チンチラの発育と繁殖初回膣開口日令・性周期・妊娠期間・性比・飼育中頻発する疾病

The paper deals with observations on growth and reproduction of the chinchilla in recent 4 years started from 1966 at this laboratory. There were large variations in age of vaginal opening (less than 71 days-308 days) with an average of 173.2+/-57.6 days in 45 females. The average length of 100 oestrus cycles in 24 females was 35.7+/-7.9 (15-62) days. The mean period of 5 gestations in 5 females was 110.4 (108-112) days. Eighty-one out of 123 litters were born between March and August during 3 years, and parturition never occurs in December. The most suitable season for reproduction of chinchillas may be from January to April, and a summer anoestrous seems to be present in August to early September as reported by Weir. The litter size ranged from 1 to 4 with a mode of 2 (46.3%) and an average of 1.90+/-0.76. More male kids were produced at birth at this laboratory, and sex ratio was 133.7 (98 females and 131 males). In 1973, 37 chinchillas gave birth to 71 kids with an average litter size of 1.92, and 59 of them were successfully weaned (1.59 per litter). Of these kids, 50 (1.35 per liter) attained 240 days of age (adulthood). Among 91 subjected to investigation for causes of death, 23 (25.3%) were dead during newborn period, and 9 and 5 adults were dead of malocclusion (9.9%) and the prolapse of rectum respectively.