PRA (Progressive retinal atrophy)中译为「进行性视网膜萎缩症」,是一种不良基因自然演化的遗传病,
简单来说,视网膜有二个部份,一个负责昏暗光线,另一个负责区别颜色和白天光线﹝我们都知道视力是由光线折射形成的﹞,而PRA则是造成此二部份退化的原凶。通常在三至五岁视力就会开始退化,初期先是狗狗在黑暗中对光线的敏感度越来越差(夜盲);中期开始白天的视力会渐渐衰退;到末期眼睛失明,直到完全看不见。
OFA所做的动物髋关节遗传性表现型评量分为七个等级,分别为正常(极好、好、正常)、模棱两可、发育不全(轻微、中度、重度)。分级的判定是由三位不同的放射显影专家来进行,最后综合三位专家的意见而获得分级的结果。例如: 1.二位专家认为是极好,一位认为是好—最后将分级为极好。 2.一位专家认为是极好,一位认为是好,一位认为是正常—最后将分级为好。 3.一位专家认为是正常,二位放射学家认为是轻微发育不良—最后将分级为轻微发育不良。极好、好、正常等三个正常范围内的分级将可获得OFA认证编号, AKC认可其有效性,相关资讯储存建档于公用资料库。模拟两可、轻微、中度、重度发育不全等四个分级的X光片资料会由OFA的放射显影专家检阅后提出报告,归纳整理出X光片中不正常案例的调查结果。除非获得饲主的许可,发育不全的X光片资料将不会公开于公用资料库。
The phenotypic evaluation of hips done by the Orthopedic Foundation for Animals falls into seven different categories. Those categories are normal (Excellent, Good, Fair), Borderline, and dysplastic (Mild, Moderate, Severe). Once each of the radiologists classifies the hip into one of the 7 phenotypes above, the final hip grade is decided by a consensus of the 3 independent outside evaluations. Examples would be: The evaluation of hips done by the Orthopedic Foundation for Animals falls into seven different categories. Those categories are normal (, , ), , and dysplastic (, , ). Once each of the radiologists classifies the hip into one of the 7 phenotypes above, the final hip grade is decided by a consensus of the 3 independent outside evaluations. Examples would be: Two radiologists reported excellent, one good—the final grade would be excellent One radiologist reported excellent, one good, one fair—the final grade would be good One radiologist reported fair, two radiologists reported mild—the final grade would be mild The hip grades of excellent, good and fair are within normal limits and are given OFA numbers. This information is accepted by AKC on dogs with permanent identification (tattoo, microchip) and is in the public domain. Radiographs of borderline, mild, moderate and severely dysplastic hip grades are reviewed by the OFA radiologist and a radiographic report is generated documenting the abnormal radiographic findings. Unless the owner has chosen the open database, dysplastic hip grades are not in the public domain.
极好:髋关节结构比较同品种同年龄的动物是属于特别优异的等级。股骨头很深地被包覆于构造良好的关节窝里,且股骨头与关节窝之间的接缝空隙非常小。关节窝几乎完全包覆股骨头。
Excellent Excellent (Figure 1): this classification is assigned for superior conformation in comparison to other animals of the same age and breed. There is a deep seated ball (femoral head) which fits tightly into a well-formed socket (acetabulum) with minimal joint space. There is almost complete coverage of the socket over the ball.
好:稍微不如极好的等级但仍能看出是一个好的髋关节结构,股骨头良好地被包覆于关节窝中,且有不错的包覆度。
Good Good (Figure 2): slightly less than superior but a well-formed congruent hip joint is visualized. The ball fits well into the socket and good coverage is present.
正常:此分级的髋关节有些许不平整的状况出现。髋关节比良好显型的髋关节还宽松。这是因为股骨头些微地滑出关节窝而造成极小程度的关节不契合。这也可能是关节窝负重表面的些微内部误差而造成关节窝看起来稍浅(图四)。然而对某些品种来说这可能是很正常的表现,如中国沙皮狗、松师狗以及贵宾。
Fair Fair (Figure 3): Assigned where minor irregularities in the hip joint exist. The hip joint is wider than a good hip phenotype. This is due to the ball slightly slipping out of the socket causing a minor degree of joint incongruency. There may also be slight inward deviation of the weight-bearing surface of the socket (dorsal acetabular rim) causing the socket to appear slightly shallow (Figure 4). This can be a normal finding in some breeds however, such as the Chinese Shar Pei, Chow Chow, and Poodle.
模棱两可:专家之间未能达成明确共识而无法将这类髋关节分入正常或发育不良的任一个分级之中。通常这类髋关节会表现出比正常(Fair)分级中更大程度的关节不契合,但却又没有显示出关节炎的变化来作为判定髋关节发育不良的条件。另外,也有可能是在髋关节解剖图上的任一个区域出现不明骨头突出物,而无法正确地判别是否为不正常的关节炎变化或者只是单一个体正常的骨骼结构差异。为了增加分级判别的正确度,建议之后再拍一次髋关节X光片(通常六个月后)。专家可藉由比较先前的与最近拍摄的X光片来观察经过一段时间后髋关节有无关节炎的变化,如果有,就可确定犬只患有髋关节发育不全症。大部份此分级的犬只(超过百分之五十)在过了一段时间后并没有发现关节炎的变化都可以重新得到正常的分级(通常都获得正常(Fair)的分级)
Borderline Borderline: there is no clear cut consensus between the radiologists to place the hip into a given category of normal or dysplastic. There is usually more incongruency present than what occurs in the minor amount found in a fair but there are no arthritic changes present that definitively diagnose the hip joint being dysplastic. There also may be a bony projection present on any of the areas of the hip anatomy illustrated above that can not accurately be assessed as being an abnormal arthritic change or as a normal anatomic variant for that individual dog. To increase the accuracy of a correct diagnosis, it is recommended to repeat the radiographs at a later date (usually 6 months). This allows the radiologist to compare the initial film with the most recent film over a given time period and assess for progressive arthritic changes that would be expected if the dog was truly dysplastic. Most dogs with this grade (over 50%) show no change in hip conformation over time and receive a normal hip rating; usually a fair hip phenotype.
轻微髋关节发育不良:股骨头微脱出关节窝造成关节窝出现不契合的状况。关节窝通常很浅,只能包覆到部份股骨头。在这个分级的髋关节通常不会看到关节炎的病理变化产生,如果犬只还年轻(24-30个月大),可以等犬只年纪更大之后再做一次检测,通常还是会被分级到轻微发育不良,且可发现早期关节炎的病理变化。髋关节发育不全症是慢性渐进式发展的疾病,年纪越大的狗,检测结果会越正确。
Mild Mild Canine Hip Dysplasia (Figure 5): there is significant subluxation present where the ball is partially out of the socket causing an incongruent increased joint space. The socket is usually shallow only partially covering the ball. There are usually no arthritic changes present with this classification and if the dog is young (24 to 30 months of age), there is an option to resubmit an radiograph when the dog is older so it can be reevaluated a second time. Most dogs will remain dysplastic showing progression of the disease with early arthritic changes. Since HD is a chronic, progressive disease, the older the dog, the more accurate the diagnosis of HD (or lack of HD).
中度髋关节发育不全:由于关节窝过浅,股骨头几乎没有固定进去关节窝中而形成一个显著脱出,造成髋关节的不契合。通常沿着股骨头的球状与骨颈部位开始会有二次性的关节炎病理变化的产生、关节窝环病变(如骨赘或骨刺)以及不同程度的骨形变化称为硬化症。一旦关节炎形成,关节炎的症状只会持续发展不会消失。
Moderate Moderate Canine Hip Dysplasia: there is significant subluxation present where the ball is barely seated into a shallow socket causing joint incongruency. There are secondary arthritic bone changes usually along the femoral neck and head (termed remodeling), acetabular rim changes (termed osteophytes or bone spurs) and various degrees of trabecular bone pattern changes called sclerosis. Once arthritis is reported, there is only continued progression of arthritis over time.
重度髋关节发育不全:从X光片中可找到显著的发育不全迹象/证据。股骨头部份或完全脱出关节窝而形成脱臼的状况。如同中度髋关节发育不全,通常沿着股骨头的球状与骨颈部位开始会有很多二次性的关节炎病理变化的产生、关节窝环病变(如骨赘或骨刺)以及很多不正常的骨型病理变化。
Severe Severe HD (Figure 6): assigned where radiographic evidence of marked dysplasia exists. There is significant subluxation present where the ball is partly or completely out of a shallow socket. Like moderate HD, there are also large amounts of secondary arthritic bone changes along the femoral neck and head, acetabular rim changes and large amounts of abnormal bone pattern changes. Other Hip Dysplasia Registries—An Approximation E A-1 0-4 (no > 3/hip) Normal G A-2 5-10 (no > 6/hip) Normal F B-1 11-18 Normal B B-2 19-25 Fast Normal M C 26-35 Noch Zugelassen Mod D 36-50 Mittlere S E 51-106 Schwere
Other Hip Dysplasia Registries—An Approximation
OFA |
FCI (European) |
BVA (UK/Australia) |
SV (Germany) |
E |
A-1 |
0-4 (no > 3/hip) |
Normal |
G |
A-2 |
5-10 (no > 6/hip) |
Normal |
F |
B-1 |
11-18 |
Normal |
B |
B-2 |
19-25 |
Fast Normal |
M |
C |
26-35 |
Noch Zugelassen |
Mod |
D |
36-50 |
Mittlere |
S |
E |
51-106 |
Schwere |
|