A case of Peters' anomaly in a springer spaniel.

An 8-week-old springer spaniel presented with a large central corneal opacity of the left globe, which was accompanied by cords of tissue spanning from the iris collarette to the posterior cornea. A posterior cortical cataract was noted in the right eye. At the owner's request the puppy was humanely destroyed, and a necropsy was performed. Upon sectioning the left globe in the vertical plane, a circle of pigmented strands of tissue was observed spanning the anterior chamber from the iris to the posterior aspect of the cornea. The right globe appeared normal when inspected grossly. Histologically, a membrane of pigmented tissue covered the posterior aspect of the broad central corneal leukoma of the left globe. This membrane and the cords traversing the anterior chamber were composed of vascular uveal tissue. Descemet's membrane and the corneal endothelium were reduced or absent in the zone of corneal opacity. Other than the changes associated with cataract, the right globe was histologically normal. The clinical and histological findings in the left globe were identical with those described for Peters> anomaly in human beings.     

Use of seminiferous tubule segments to study stage specificity of unscheduled DNA synthesis in rat spermatogenic cells

DNA repair in spermatogenic cells at various stages of maturity was determined by quantitation of unscheduled DNA synthesis (UDS). Male F-344 rats were exposed (i.p.) to methyl methanesulfonate (MMS, 35 mg/kg); 1 hr later, segments of seminiferous tubules corresponding to spermatogenesis stages II, IV-V, VI, VII, VIII, IX-X, XII, and XIV were isolated with the transillumination pattern of the tubules as a guide. Intact tubule segments were cultured 24 hr in the presence of [3H]thymidine, and UDS was quantitated by autoradiography as net grains/nucleus (NG). In primary spermatocytes from treated rats, NG count increased with increasing maturity from leptotene primary spermatocytes (3.5 NG) up through stage VIII and IX-X pachytene spermatocytes (22 NG), after which NG decreased in stage-XII pachytene and diplotene spermatocytes (to 16 NG and 8 NG, respectively). Round spermatids of steps 2-8 of spermiogenesis all exhibited approximately the same UDS response (8 NG). Elongating spermatids as mature as step 14 underwent UDS after exposure to MMS, but step-15 and later-step spermatids did not. The DNA repair response of pachytene spermatocytes cultured within segments of seminiferous tubule corresponding to stages VIII and IX-X was 4 to 25 times greater, depending on the dose of MMS, than pachytene spermatocytes isolated by enzymatic digestion and cultured in suspension [Bentley and Working, Mutat Res 203:135-142, 1988]. Thus, the use of segments of seminiferous tubule both increased the sensitivity of UDS as an indicator of DNA damage in rat germ cells and enabled the study of UDS in spermatogenic cells at different stages of maturity.     

A histopathologic evaluation of nevocellular nevi in pregnancy

A detailed histopathologic study was performed on 128 nevi removed from 86 pregnant white patients. None of the patients had clinical evidence of the dysplastic nevus syndrome, and none of the excised nevi were clinically suspicious for melanoma. One third of patients reported some change in nevi during pregnancy. Nevi from an age-matched male control population (50 patients) had a spectrum of histologic features essentially identical to the pregnant patients, while nevi from a female control population (51 patients) showed slightly less atypia according to our criteria. The differences found between the nevi from pregnant and control women suggest that a mild degree of histopathologic atypia or "activation" is associated with pregnancy. However, in the population studied, these changes were never of sufficient degree to result in diagnostic confusion.     

Complex and simple coronary artery stenoses: a new way to interpret coronary angiograms based on morphologic features of lesions

For many years, atherosclerotic coronary artery lesions have been described by angiographers only in terms of location and degree of narrowing. However, it has become apparent that coronary stenoses generally have distinct morphologic features that can be recognized at angiography and that allow them to be classified as either "simple" or "complex" plaques. Complex plaques are those characterized by ulcerated or ruptured surfaces, subintimal hemorrhage, superimposed partially occluding thrombi, recanalized thrombi, or some combination. Pathologic studies have shown a very high frequency of these lesions at sites of total thrombotic occlusion of coronary arteries. Clinical and angiographic studies have demonstrated a high frequency of such lesions in living patients with both unstable angina and acute myocardial infarction. The presence of complex stenoses has also been found to increase the risk of future myocardial infarction. Plaque morphology thus appears to significantly affect the prognosis of patients with coronary disease and should be carefully evaluated in interpretation of all coronary angiograms.     

Current tuberculosis screening practices.

Health department officials in all 50 states and 14 major cities responded to a survey questionnaire designed to obtain information about current tuberculosis screening practices. Persons being screened fell into the groups designated as high risk by the American Thoracic Society (ATS) and the Centers for Disease Control (CDC). The methods used for screening were generally those advocated by ATS, CDC, and the Food and Drug Administration (FDA), although chest radiographs continue to be overused. Screening in about one-half of the groups is mandated by law or regulation. There appears to be some confusion about the circumstances in which "two-step" tuberculin testing should be used. Data on the productivity and costs of screening activities were very limited. We encourage those responsible for tuberculosis screening programs to evaluate them, discontinue those which are unproductive, and intensify those which are productive.     

双—对二甲氨基苯甲醛缩二胺类希夫碱合成、表征及抗菌活性

目的：合成双－对二甲氨基苯甲醛缩二胺类希夫碱,并对其抗菌活性进行研究。方法：以对二甲氨基苯甲醛和二胺类为原料,经缩合反应,制得4种相应希夫碱。结果：结构经元素分析、红外光谱、核磁共振谱确定,4种化合物均未见文献报道,抗菌活性测试表明,它们具有一定抗菌活性。结论：乙酸是催化剂,对缩合反应有利,希夫碱化合物具有一定抗菌活性。     

Proteoglycan depletion alone is not sufficient to stimulate proteoglycan synthesis in cultured bovine cartilage explants

Articular cartilage comprises a small number of cells embedded within a matrix primarily composed of collagen and proteoglycan (PG). The functional integrity of the tissue is highly dependent on the maintenance of matrix structure, which, in turn, is controlled by the chondrocytes. In normal tissue there is a slow but steady turnover of matrix components such that their levels remain constant. In certain diseased states the equilibrium is upset, resulting in a net loss of matrix components. The object of the present study was to artificially upset the synthetic/loss equilibrium by enzymic depletion and assess the ability of chondrocytes to respond by increasing PG synthesis. Cultured bovine articular cartilage explants were depleted using enzymes as follows; 10 U/ml Streptomyces hyaluronidase (induced a 30% loss of PG), 2000 U/ml testicular hyaluronidase (70% loss of PG) and 100 U/ml collagenase (35% loss of PG) and control (6% loss of PG). Collagenase also induced a 50% loss of collagen. Collagenase treatment induced a 50% stimulation of PG synthesis above control levels. Elevated synthesis levels were maintained for 9 days. Testicular hyaluronidase induced a brief elevation in PG synthesis on day 3 of culture. Streptomyces hyaluronidase treatment did not cause an alteration in the rate of PG synthesis above control levels. Histological examination indicated that collagenase-treated explants formed outgrowths consisting of rounded chondrocytes within a fine fibrous matrix which stained intensely with safranin-O, indicating a high concentration of PG. The production of repair-like outgrowths may explain the elevated PG synthesis rates measured. It appears, therefore, that collagen and matrix organization is more important than PG levels in the control of PG synthesis in articular cartilage explant cultures.     

Proceedings of the Symposium ‘Angiotensin AT1 Receptors: From Molecular Physiology to Therapeutics’: FUNCTIONS OF ANGIOTENSIN PEPTIDES IN THE ROSTRAL VENTROLATERAL MEDULLA

• 1 It was first shown several years ago that the rostral part of the ventrolateral medulla (VLM) contains a high density of receptor binding sites for angiotensin II (AngII). In the present paper we briefly review recent studies aimed at determining the actions of both exogenous and endogenous angiotensin peptides in the rostral VLM, as well as their specific sites of action.
• 2 The results of these studies have shown that angiotensin peptides can excite pressor and sympathoexcitatory neurons in the rostral VLM, but do not appear to affect non-cardiovascular neurons in this region.
• 3 It is known that pressor neurons in the rostral VLM include both catecholamine and non-catecholamine neurons. There is evidence that, at least in conscious rabbits, both of these types of neurons are activated by AngII. The specific endogenous angiotensin peptide or peptides that affect pressor neurons in the rostral VLM have not yet been definitively identified.
• 4 It is also possible that different angiotensin peptides may have different effects on pressor neurons in the rostral VLM, mediated by different receptors. Further studies will be needed to define these different functions as well as the specific receptors and cellular mechanisms that subserve them.