Biomedical subjects

D G Perkins

Publications and source records attributed to D G Perkins.

50 records · Page 3Linked to original sources

PubMed1985

Experimental low colorectal anastomosis.

The authors evaluated a side-to-end colorectal anastomosis carried out by the abdominoperineal approach, in which opening of the mucosal layer of the colon, and therefore the lumen, is delayed for 4 days. This technique was compared to transabdominal end-to-end anastomosis performed as low as possible, using the circular stapler and hand-sewing with a one-layer technique. Experimental end-to-end stapled and hand-sewn anastomoses were performed randomly in 24 female mongrel dogs. The operating time was similar for each group. Anastomoses were examined for leaks at 7 to 10 days digitally and by roentgenography after barium enema. At sacrifice 14 days after anastomosis, measurements were made of bursting strength and the distance of anastomoses from the anus. The degree of inflammation was evaluated histologically. There were three leaks in the hand-sewn anastomoses and none in the experimental end-to-end stapled anastomoses. The mean bursting strength was similar for all three techniques. The mean distance from the anus was lowest for the experimental anastomoses. Inflammatory changes were least in the end-to-end stapled anastomoses. Two dogs in this group and one in the experimental group were incontinent postoperatively. The experimental anastomosis compares favourably to end-to-end stapled and hand-sewn anastomoses and may have some advantages for low anastomosis in man.

Animals↗

PubMed1984

Hemodynamic modification of aortic atherosclerosis. Effects of propranolol vs hydralazine in hypertensive hyperlipidemic rabbits.

According to hemodynamic theories of atherogenesis, atherosclerotic plaques are a reaction to endothelial damage caused by arterial flow disturbances such as turbulence. Earlier studies showed that hydralazine increased, whereas propranolol decreased, the product of heart rate X blood velocity, a predictor of arterial flow disturbances, and that hydralazine aggravated, whereas propranolol decreased turbulence in the region of carotid artery stenosis. This study was done to test the hypothesis that drugs which reduce arterial flow disturbances may be more effective in preventing atherosclerosis, than antihypertensive drugs which worsen arterial flow disturbances. Eighty-three New Zealand white rabbits were made hypertensive by a one-kidney Goldblatt procedure, and were fed a 1% cholesterol diet. Untreated hypertensive (P less than 0.01) and hydralazine-treated hypertensive rabbits (P less than 0.05) had significantly more atherosclerosis than did the normotensive controls; propranolol-treated rabbits did not differ significantly from the normotensive controls. Analysis of covariance showed that propranolol-treated rabbits had significantly less atherosclerosis than hydralazine-treated rabbits with blood pressure (P less than 0.04) or heart rate (P less than 0.006) as the covariates.

Animals↗

PubMed1984

Surgical repair of Wolff-Parkinson-White syndrome: a new closed-heart technique.

The conventional operation for ablation of accessory pathways in Wolff-Parkinson-White (WPW) syndrome requires an endocardial approach and necessitates cardiopulmonary bypass and hypothermic cardiac arrest. Cryosurgical ablation of these pathways from the epicardial surface has been described but limited to superficial accessory pathways. We report a new closed-heart technique combining dissection of the atrioventricular (AV) pad and cryosurgery. Six patients with WPW syndrome underwent operation for ablation of accessory pathways associated with disabling tachyarrhythmia refractory to medical management. All pathways were located in the left lateral AV sulcus as determined by preoperative and intraoperative electrophysiological assessment. The heart was exposed through a median sternotomy. The AV fat pad and its vascular contents were dissected away from the atrium at the site of the pathway. A small segment of the ventricle adjacent to the sulcus was exposed. The fat pad was retracted to avoid cryoinjury to the coronary vessels. A cryoprobe, 1.5 cm in diameter, was applied to the exposed AV junction (-60 degrees C for 2 minutes) to create transmural fibrosis. After ablation of the pathway was verified, the chest was closed. All 6 patients have remained free from preexcitation during short-term follow-up. This simplified technique is applicable to patients with free wall accessory pathways. This group constitutes the majority of symptomatic patients with WPW syndrome at our institution.

Adolescent↗

PubMed1984

Surgical correction of the Wolff-Parkinson-White syndrome in the closed heart using cryosurgery: a simplified approach.

The conventional operation for ablation of accessory atrioventricular (AV) pathways in the Wolff-Parkinson-White syndrome requires an endocardial approach to the AV groove and necessitates the use of cardiopulmonary bypass and induced cardiac arrest. The feasibility of creating transmural atrial fibrosis at the level of the AV anulus in the closed heart in dogs without damaging the vascular contents of the AV fat pad was demonstrated. This was done by dissecting the fat pad from the atrium and applying a cryoprobe to the exposed atrial-anular region after retraction of the fat pad. The technique was then applied to successfully ablate 12 left parietal wall accessory pathways in 11 patients with the Wolff-Parkinson-White syndrome. This simplified approach to any parietal wall accessory pathway does not require cardiopulmonary bypass or induced cardiac arrest and may broaden the indications for this operation.

Adolescent↗

PubMed1984

[Surgical section of the bundle of Kent in the closed heart].

The conventional operation for ablation of accessory pathways (AP) in the WPW syndrome requires an endocardial approach and necessitates cardiopulmonary bypass and hypothermic cardiac arrest. Cryosurgical ablation of AP from the epicardial surface has been described but was limited to superficial AP. We report a new closed-heart technique combining dissection of AV pad and cryosurgery. Eight patients with WPW syndrome, aged 6-56, underwent surgery for ablation of AP associated with disabling tachyarrhythmia refractory to medical management. All AP were located in the left lateral AV sulcus as determined by preoperative and intraoperative electrophysiological assessment. The heart was exposed through a median sternotomy. The AV fat pad and its vascular contents were dissected away from the atrium at the site of the AP, sacrificing some atrial vessels. The dissection left some fat adherent to the thin-walled atrium close to the level of the mitral annulus. A small segment of the ventricle adjacent to the sulcus was exposed. The fat pad was retracted to avoid cryo-injury to the coronary vessels. A cryoprobe (1.5 cm diameter) was applied to the exposed AV junction (-60 degrees C for 2 minutes) to create transmural fibrosis. After verification of AP ablation, the chest was closed. All 8 patients have remained free of preexcitation during short term follow-up (1 to 8 months). This simplified technique is applicable to patients with free-wall AP, a group constituting the majority of symptomatic WPW patients at our institution.

Adult↗

PubMed1983

Ultrastructure and mechanical properties of chordae tendineae from a myxomatous tricuspid valve.

The ultrastructure and mechanical properties of chordae from a surgically removed myxomatous tricuspid valve were examined. Transmission and scanning electron microscopy showed the internal structure of the abnormal chordae to consist of a loose and relatively sparse network of disorganized collagen fibrils, with no well defined collagen bundles present. The abnormal tissue was found to be more extensible than normal and it ruptured at a stress that was only about 6% of the breaking stress for normal chordae. Chordal rupture, a common complication in this disorder, can be attributed to this decrease in chordal strength. At high strains, a decreased elastic modulus was also observed, which may be attributed to tissue changes and an alteration in collagen fibril structure and/or composition.

Aged↗

PubMed1982

Ultrastructure of myocardium in the Hurler syndrome. Possible relation to cardiac function.

Cardiac tissues obtained at post mortem examination of eight patients with the Hurler syndrome, who ranged in age from 5 to 23 years, were examined by histochemical methods and electron microscopy. Extensive myocardiocytic vacuolization and increased interstitial fibrous tissue were noted by light microscopy in all hearts. The cytoplasmic (perinuclear) vacuoles contained Luxol-fast-blue-positive substance. At the ultrastructural level, abnormal cytoplasmic organelles were present within the myocardiocytes in all patients. These organelles were of three types: zebra bodies (ZB), membranous cytoplasmic bodies (MCB) and granulomembranous bodies (GMB). As ZB and MCB are believed to represent the morphological counterpart of accumulated gangliosides, these substances rather than glycosaminoglycans appear to be stored within myocardiocytes of patients with the Hurler syndrome. The accumulation of gangliosides and the consequent damage to the myocardial substratum probably contributes to the clinically evident cardiac disease, so often observed in the patients with this disorder.

Adolescent↗

PubMed1981

Aortic atherosclerosis in hypertensive rabbits treated with anti-hypertensive agents having different effects on arterial flow disturbances. 1. Extent of surface involvement.

Hypertension may be considered a disorder of increased energy in the blood, with two components: increased pressure energy may promote arteriolar disease, whereas arterial diseases such as atherosclerosis may be more closely related to flow disturbances (turbulence, boundary layer separation, high shear, or axial stream impingement) due to increased kinetic energy. Previous studies have shown that hydralazine aggravates turbulence in stenosed carotid arteries, whereas propranolol diminishes turbulence. To assess the effect of these drugs on the progression of atherosclerosis, the drugs were administered subcutaneously to rabbits made hypertensive (one kidney Goldblatt) and hypercholesterolemic (1% cholesterol diet for 4 weeks). Appropriate controls with normal, only hypertensive and hypertensive-hypercholesterolemic untreated rabbits were employed. A total of 36 rabbits was used. The extent of the aortic surface involvement with atherosclerotic lesions was assessed by morphometric analysis of magnified photographs. Although the extent or surface involvement did not differ significantly between the untreated or treated hypertensive rabbits, there was an interesting difference in the relationship between blood pressure and extent of surface involvement. In the untreated and hydralazine treated rabbits, there was a direct correlation between increasing blood pressure and extent of lesions; in the propranolol treated group, this relationship was abolished.

Animals↗

PubMed1980

Placental infiltration in congenital neuroblastoma: a case study with ultrastructure.

Examination of a large, oedematous placenta of a still-born infant showed an extensive infiltration of chorionic villi by malignant cells; the nature of these was not apparent by light microscopy. Ultrastructural examination of these cells showed the presence of cytoplasmic granules whose size and appearance were consistent with those characteristically present in neuroblastomas. Whereas no necropsy was carried out on the still-born infant, it may be assumed, in keeping with the available data, that the placental metastases were derived from a congenital neuroblastoma. Infiltration of the villous stroma by metastatic neuroblastoma observed in the present case was not reported previously as in all other known instances the metastatic neuroblastomatous cells were confined to the lumina of the chorionic vessels.

Female↗

PubMed1976

Sliding of the epithelium in experimental corneal wounds.

The corneal epithelial cell has a unique sliding capability. The epithelial cell spreads and migrates in an amebic fashion without mitotic activity when the continuity of the epithelium is broken. This movement is demonstrated both in vivo and in vitro. Prompt sliding for sealing the wound defect is apparently the first step of the wound healing of the superficial cornea. Cut edges of collagen fibers show no sign of activity towards healing the wound. The energy source of the sliding is provided mainly from stored glycogen in the epithelial cells. Sliding is inhibited by removal of glycogen from the cell or by adding glycolytic enzyme inhibitors.

Animals↗

PubMedDate not supplied

Fine needle aspiration biopsy of epithelioid angiomyolipoma. A case report.

BACKGROUND: Epithelioid angiomyolipoma (AMYL) is a variant of angiomyolipoma characterized by sheets of epithelioid cells that may mimic renal cell carcinoma. This is the first report describing the fine needle aspiration biopsy features of this lesion. CASE: A 47-year-old man with a history of epithelioid angiomyolipoma of the kidney treated with nephrectomy nine months previously presented with a recurrent retroperitoneal mass and multiple nodular liver lesions. Fine needle aspiration biopsy of one of the liver lesions showed fragments and sheets of noncohesive epithelioid cells with thin cytoplasm, markedly atypical nuclei, and scattered bizarre and multinucleated forms. The epithelioid cells focally expressed HMB-45 and were nonimmunoreactive, with epithelial markers. CONCLUSION: Epithelioid AMYL may pose differential diagnostic problems with high grade carcinoma, especially renal cell, hepatocellular and metastatic carcinoma. An awareness of this entity and its characteristic cytologic features and immunoreactivity with HMB-45 is helpful in its identification.

Angiomyolipoma↗

PubMedDate not supplied

Papillary thyroid carcinoma and related thyroid neoplastic lesions: a light microscopic study with emphasis on nuclear changes.

A total of 187 thyroid lesions consisting of 2 cases of Grave's disease, 21 cases of multinodular goiter, 40 follicular adenomas and 124 low-grade papillary thyroid carcinomas were studied to identify intermediate neoplastic lesions in the spectrum of nuclear changes between benign reactive thyroid follicles and low-grade thyroid papillary carcinoma. The lesions were examined and classified on the basis of the following nuclear features: fine chromatin seen in the thyroid papillary carcinomas and coarse chromatin seen in follicular carcinomas. Cases with Hürthle cell changes were excluded from the study. Cases with nuclei containing coarse chromatin were classified in the group of follicular adenomas with a coarse chromatin pattern. The neoplastic thyroid lesions containing fine chromatin showed a spectrum of nuclear changes ranging between reactive follicular lesions and papillary thyroid carcinoma with lymph node metastasis. Such lesions were classified as follicular adenomas with a fine chromatin pattern. The nuclei of these lesions were graded into mild to marked "nuclear atypia with a fine chromatin pattern". The degree of atypia depended on the degree and extent of nuclear changes. Encapsulated follicular adenomas with a fine chromatin pattern and with mild atypia (11 cases), moderate atypia (13 cases), marked atypia (27 cases), and encapsulated or nonencapsulated papillary thyroid carcinoma were characterized by uniform nuclei; with mild, moderate and marked nuclear atypia in less than 2/3 of the cell population and marked nuclear atypia in more than 2/3 of the cell population; and measuring 5.4-6.3, 6.0-7.2, 6.3-9 and 7.2-10 microns in diameter, respectively. Follow-up of cases of papillary thyroid carcinoma fulfilling the above criteria showed lymph node metastasis in 33% of cases, whereas follicular adenomas with a fine chromatin pattern, including cases originally diagnosed as papillary carcinoma, showed no evidence of lymph node or distant metastasis in a follow-up period of 30 months to 15 years. In the thyroid tissue surrounding papillary thyroid carcinoma or encapsulated follicular adenoma with a fine chromatin pattern and marked atypia, adenomatous nodules with a fine chromatin pattern and with low-grade nuclear atypia were identified. The adenomatous nodules with a fine chromatin pattern and with mild, moderate and marked atypia showed architectural, cytoplasmic and nuclear features similar to those of follicular adenoma with a fine chromatin pattern of the same grade. Of interest, a large number of cases of follicular adenoma with a fine chromatin pattern had areas with features of follicular adenoma with a coarse chromatin pattern.

Adenoma↗

PubMedDate not supplied

Ret oncogene protein expression in papillary thyroid carcinoma and related lesions.

BACKGROUND: Activation of Ret oncogenes, particularly Ret/PTC, has been identified in papillary thyroid carcinoma (PTC). The purpose of this study was to investigate the immunostaining pattern of Ret oncogene protein in PTC and nodular non-PTC lesions with a fine chromatin pattern. MATERIALS AND METHODS: Ninety-three PTC and 139 nodular non-PTC lesions were microscopically reviewed to identify the nuclear changes of "limited nuclear features of PTC" (focal nuclear grooves, nuclear inclusions or optically clear nuclei) and areas of infiltrating carcinoma (IC) and were submitted for immunostaining with Ret oncogene protein antiserum. RESULTS: Immunoreactivity for Ret protein ranged from negative in follicular adenoma (FA) with a coarse chromatin pattern, to negative or weak reactivity in FA with a fine chromatin pattern, to strong reactivity in PTC with areas of infiltrating carcinoma (IC). In FA with fine chromatin, FA and follicular carcinoma (FC) containing an admixture of areas of coarse and fine chromatin, areas with nuclear changes with "limited nuclear features of PTC" displayed varying degrees of immunoreactivity. The intensity of immunostaining varied with the degree of nuclear change. The noninvasive component of PTC with IC usually showed more extensive and stronger reactivity than PTC without IC. PTCs with and without IC were associated with a rate of lymph node metastasis of 48% and 3%, respectively. CONCLUSIONS: The expression of Ret oncogenes (Ret/PTC, other unknown variants or wild type) is focally or extensively present in all PTC with IC. The degree of immunoreactivity is likely to be proportional to the potential for lymph node metastasis of PTC. In the context of this study and due to the specificity of Ret oncogenes, it is likely that nodular non-PTC lesions with a fine chromatin pattern and focal positive reactivity for Ret oncogene represent PTC-related lesions.

Carcinoma, Papillary↗

PubMedDate not supplied

Basaloid carcinoma of the lung with bronchiolo-alveolar cell differentiation. A case report.

AIMS: We report a case of pulmonary basaloid carcinoma with bronchiolo-alveolar cell differentiation. PATIENTS AND RESULTS: A 75 year-old presented with a tumor measured 2.0 cm and was located in the periphery of the left upper lobe. Histologically, the lesion consisted of nests of basaloid cells, and lumina and clefts lined by tumor cells with features of mucous cells or type II pneumocytes or with mixed features. CONCLUSIONS: Previously reported basaloid carcinomas of the upper aero-digestive tract and lung have been purported to have an aggressive behavior. The tumor in the present study had features of a histopathological low grade tumor including a low mitotic rate, no tumor necrosis and a growth pattern at the periphery similar to that of bronchiolo-alveolar carcinoma.

Aged↗