The histopathology of freezing injury to the rat spinal cord. A light microscope study. I. Early degenerative changes

In an effort to develop a method of tissue injury which would provide a model for the study of axonal regrowth in adult mammalian central nervous system (CNS), we have analyzed the effects of freezing in the dorsal columns of more than 200 rat spinal cords. The effects of temperature and time of exposure upon the size, shape, distribution and histologic characteristics of the lesion have been assessed during the first seven days following the injury. The upper threshold for injury occurs at -3 degrees C for 15 minutes. Between -3 degrees C and -12 degrees C the tissue changes vary in extent and characteristics. Selective damage to axons and myelin occurs with sparing of the supportive cells followed by proliferation of a cellular matrix. At seven days, the lesions produced by -8 degrees C for 15 to 60 minutes have neither axons nor myelin sheaths and consist of a dense cellular matrix of macrophages and presumed glial cells. With these tissue characteristics, and the preservation of tissue continuity without obstructive barriers, this model would appear to be potentially suitable for the study of axonal regrowth potential in mammalian CNS.     

Radiotherapy in the treatment of low-grade astrocytomas

Between 1954 and 1986 inclusive, 160 children in the North West Region of England were registered with histologically proven lowgrade astrocytomas (grade 1 or 2). Ten died before receiving any treatment, and a further seven died within 28 days of surgery, leaving 143 children whose survival in relation to treatment modality is the subject of this paper. Low-grade astrocytomas are responsive to radiation therapy. This treatment has no clear benefit to offer children with superficial tumours that can be resected completely or nearly so, but significantly improves survival rates when tumours are deep-seated and not amenable to excision.     

FEASIBILITY OF CONDUCTING CARDIOVASCULAR OUTCOME RESEARCH IN AUSTRALIAN GENERAL PRACTICE: RESULTS FROM THE ANBP2 PILOT STUDY

1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.     

Intrathoracic meningocele associated with neurofibromatosis: case report

The authors present a case of intrathoracic meningocele associated with neurofibromatosis. Computed tomography with metrizamide myelography proved valuable in locating the lesion, thus facilitating surgical intervention. With the preoperative diagnosis established and the severity of the meningocele known, the surgeons safely employed a subpleural approach at thoracotomy.     

急性重型颅脑损伤ET和CGRP含量变化及其临床意义

目的　探讨急性重型颅脑损伤 (ASBI)患者血浆中内皮素 (ET)和降钙素基因相关肽 (CGRP)的含量变化及其临床意义。方法　用放免法测定 2 8例ASBI患者伤后 6～ 2 4h血浆中ET及CGRP含量。结果　ASBI患者ET含量明显增多 ,差别有显著性 (P <0 .0 5 ) ;CGRP也有一定的增多 ,但无显著性差异。结论　ET和CGRP共同参与ASBI病理生理反应过程 ,ET释放增加是加重脑继发性损害的重要因素     

Medium-chain triglycerides in neonatal nutrition. Absence of inhibition of lipogenesis and of laxative effect

Eighteen neonates ranging in birthweight from 820 to 1570 gm and in gestational age from 29 to 35 weeks were assigned alternately and blindly to feedings with formulas containing 14 or 50% of their fat as medium-chain triglycerides (MCT). Mean daily intakes of formula and mean daily weight gains were similar in neonates in the two groups. Consistency of stools and mean weekly increments in skinfold thickness were not affected by the MCT content of the formula. This suggests that under ordinary clinical conditions, medium-chain triglycerides exert no laxative effect nor affect adversely the deposition of subcutaneous fat in very low-birthweight neonates.     

The American Association for Pediatric Ophthalmology and Strabismus workforce distribution project.

PURPOSE: To describe data sources and functional utility of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) workforce database and associated map files. METHODS: Population data from the 2000 U.S. Census and current listings from the AAPOS and American Academy of Ophthalmology (AAO) databases were organized to demonstrate and analyze practitioner-to-population relationships for metropolitan statistical areas nationwide. An interactive map was developed to provide an intuitive graphical display of the data. RESULTS: A total of 749 active AAPOS members were distributed in 154 of 280 defined metropolitan statistical areas. Within these areas, a 0- to 20-year age subgroup varied from 17.8% to 42.6%, with an average of 30.4%. The AAPOS member-to-million-person ratio varied from 1.3 to 27, with higher numbers generally representing regions with population bases inadequately defined by Census Bureau statistical area definitions. Ratios for a majority of larger, better-defined areas ranged from 3 to 4 AAPOS members per million persons. Sizable areas with no AAPOS member presence were identified and tabulated. AAO members with a specified pediatric practice focus who were not AAPOS members were identified in 103 areas, possibly influencing patient choices and practitioner referrals for these regions. CONCLUSIONS: The AAPOS workforce database and related interactive map display practitioner and population data that may assist physicians and planners in targeting practice development and identifying potentially underserved areas.     

Effects of Ethanol Exposure during the Third Trimester Equivalent on Neuron Number in Rat Hippocampus and Dentate Gyrus

An artificial rearing procedure was used to expose neonatal rats to a formula containing 3.74% ethanol during postnatal days 4 through 10. This treatment produced a mean blood ethanol concentration of 379.8 +/- 17.3 mg/dl. When the pups were killed on the afternoon of postnatal day 10, brain weight to body weight ratio in the ethanol-exposed rats was reduced 22.4% and 21.5% compared to suckle and pair-fed controls, respectively. Ethanol exposure also resulted in a 16% reduction of neurons in hippocampal field CA4, compared to controls, but did not produce deficits in fields CA1 or CA3. There was also a 10% increase in the number of neurons (a population of cells in the midst of a proliferative phase at the time of the exposure) in the granule cell layer of the dentate gyrus. The ethanol exposure did not affect cell size in any of the four neuron populations measured. These results suggest, that within the dose and timing parameters examined, ethanol exposure during the third trimester equivalent appears to be preferentially harmful to specific populations of developing neurons.