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Biomedical subjects

D G Perkins

Publications and source records attributed to D G Perkins.

At least 37 records · Page 2Linked to original sources
PubMed1998

Development of endometriosis from embryonic duct remnants.

Among 18 cases of endometriosis involving ovaries and fallopian tubes, we identified three cases with foci of endometriosis adjacent to the embryonic duct remnants in the fallopian tube. The serial sections of the blocks of tissue containing areas of interest showed segments of embryonic duct remnants with changes suggestive of gradual transformation to endometrial glands. The early changes consisted of replacement of the muscular coat surrounding the epithelium of embryonic duct remnants by the endometrial stroma with positive immunoreactivities for estrogen receptor. Subsequently there were changes of the embryonic duct remnant epithelium into endometrial epithelium with diffuse immunoreactivities for estrogen receptor. The significance of this transformation as a mechanism of development of endometriosis is discussed.

Adult↗
PubMed1998

Infiltrating papillary thyroid carcinoma: review of 134 cases of papillary carcinoma.

BACKGROUND: Papillary thyroid carcinomas (PTCs) are diagnosed mainly by the features of nuclei of the neoplastic cells. Theoretically, by similarity to other types of carcinoma, infiltrative tumor growth likely distinguishes the thyroid neoplastic lesions with potential of metastasis from those without this capability. METHODS: One hundred thirty-four cases of PTC, consisting of 41 encapsulated tumors and 93 nonencapsulated tumors, were examined for the presence of infiltrating PTC (IPTC), defined by tumor cells infiltrating a desmoplastic or sclerotic stroma. RESULTS: Encapsulated tumors with focal or extensive IPTC and nonencapsulated tumors with focal or extensive IPTC were associated with rates of lymph node metastases of 28%, 42%, 36%, and 65%, respectively. The tall cell variant of PTC was associated with a higher rate of metastasis. There was a small group of tumors without identifiable IPTC, designated as PTC without identifiable infiltrating carcinoma, which included six encapsulated tumors with areas of sclerosis in the capsule and three nonencapsulated tumors consisting of neoplastic cells with optically clear nuclei, nuclear grooves, and intranuclear inclusions in over two thirds of the cell population. Of these lesions, one case developed lymph node metastases. Papillary thyroid tumors without areas of IPTC and exhibiting the nuclear changes described, but in less than two thirds of the tumor cells, did not develop lymph node metastases. CONCLUSIONS: Infiltrating tumor growth is an indicator of malignant behavior in most thyroid papillary neoplastic lesions. The extent of IPTC is likely proportional to the rate of lymph node metastases.

Carcinoma, Papillary↗
PubMed1997

Pathogenetic role of the stromal cells in endometriosis and adenomyosis.

Ten cases of endometriosis of bowel, ovaries, uterine serosa and 10 cases of adenomyosis were studied. Blocks of tissue with areas of interest were submitted for serial sectioning of the entire block. Some sections were immunostained for oestrogen receptor, vimentin, Ber-EP-4 and cytokeratins. The common finding was the presence of type 1 nodules, consisting of isolated nodules of endometrial stromal cells without endometrial glands, along blood or lymphatic vessels. The stromal cells showed positive immunoreactivities for oestrogen receptor and vimentin, and negative reactivities for cytokeratins. Due to the absence of connection with adjacent endometriosis or adenomyosis, it is likely that these endometrial stromal nodules arise from the multipotential pericytes. In addition, in serosa of all cases of endometriosis, type 2 nodules, having adjacent mesothelium (Ber-EP4-) changing into epithelium (Ber-EP4+) and type 3 nodules, with non-endometrial epithelium (oestrogen receptor-) changing into endometrial gland (oestrogen receptor+) were identified. We believe that the formation of type 1 nodules from the pericytes and the transformation of the mesothelium into endometrial glands in type 2 and 3 nodules are accomplished through the process of induction by the endometrial stroma, and the proliferation is controlled by genetic, hormonal and immunological factors. Type 1, 2 and 3 nodules are likely to represent a histological continuum in the development of early endometriosis. Subsequent to the formation of endometriosis in the serosa, the pathway of development of endometriosis and adenomyosis is similar. Through the processes of induction and proliferation there is an increase in size of the stroma of type 1 nodules and that of endometrial tissue with subsequent fusion of the stroma of type 1 nodules and that of foci of adenomyosis or endometriosis. Consequently, there is enlargement of the stroma of the foci of adenomyosis or endometriosis. The 'newly enlarged stroma' serves as 'new soil' for further growth of the endometrial glands in the endometrial tissue.

Adult↗
PubMed1996

Absence of serum prostate-specific antigen and loss of tissue immunoreactive prostatic markers in advanced prostatic adenocarcinoma after hormonal therapy: a report of two cases.

We report two cases of advanced prostatic adenocarcinoma (PA) showing complete loss of three tissue immunoreactive prostatic markers, ie, prostate-specific antigen (PSA), prostatic acid phosphatase (PAP), and Leu-7 (CD57), with absence of elevated serum PSA level, despite tumor progression after hormonal therapy with or without radiotherapy. The pretreatment serum PAP in the first case and serum PAP and PSA in the second case were elevated. In both cases, the prostatic adenocarcinoma in the initial transurethral resection specimens showed positive immunoreactivity with three prostatic markers. After treatment, in both cases, the serum PSA were undetectable, and tumor cell immunostaining for three prostatic markers was negative. In addition, the posttreatment tumors in both cases showed increased number of tumor cells with neuroendocrine differentiation in comparison those in the pretreatment tumors. Although early PA without elevated serum level of PSA is common, advanced PA with absence of elevated serum PSA, associated with presence of tissue immunoreactive prostatic markers are rare. This is the first report of advanced prostatic adenocarcinomas showing loss of tumor cell prostate-specific markers with absence of elevated serum PSA level after hormonal therapy despite tumor progression.

Adenocarcinoma↗
PubMed1994

Unusual immunostaining pattern of chromogranin in normal urothelium and in transitional cell neoplasms.

We report an unusual pattern of immunostaining for chromogranin A in 24 transitional cell carcinomas (TCC). Positive immunostaining was seen with chromogranin A antisera in 10 of 16 urinary bladder TCC, neither of 2 prostatic TCC, 3 of 3 ureteral TCC and 2 of 3 metastatic TCC. This staining was demonstrated within the cytoplasm of transitional cells at all levels of the neoplastic epithelium, including cells near the basement membrane and at the free surface (umbrella cells). In 5 of 7 cases there was also immunoreactivity of the non-neoplastic urothelium. Immunostaining with neuron-specific enolase and synaptophysin was negative in all of these cases and no neuro-secretory granules were identified in 7 cases examined by electron microscopy. This pattern of immunostaining is probably due to reactivity with chromogranins or certain chromogranin-like proteins in the transitional cells, particularly in the umbrella cells.

Carcinoma, Transitional Cell↗
PubMed1994

Systemic arterial supply to the lung without sequestration: an unusual cause of hemoptysis.

Systemic arterial supply to the lung without sequestration is an unusual vascular anomaly in which a portion of normal lung tissue is supplied by an artery arising from the aorta. This entity shares some features with bronchopulmonary sequestration and hypogenetic lung (scimitar syndrome) but has unique imaging features that allow preoperative diagnosis. The authors describe such a case in a 21-year-old man who presented with hemoptysis.

Adult↗
PubMed1993

Prostate cancer trends in Canada: rising incidence or increased detection?

OBJECTIVES: To analyse trends in the incidence and mortality rates of prostate cancer in Canada according to age distribution, temporal pattern and provincial variation; to determine any association with the rate of prostatectomy; and to determine whether any observed increase in the rate of prostate cancer was due to an increase in the detection rate. DESIGN: Descriptive epidemiologic study based on Canadian population data from 1959 to 1989 and chart review from one Canadian hospital. SETTING: The chart review was conducted at the Ottawa Civic Hospital. SUBJECTS: The data on prostate cancer trends were obtained from the Canadian population. Charts were reviewed for two groups of patients: (a) men discharged from inpatient care during 1976 and 1986-87 with prostate cancer first diagnosed in the same year and (b) men who underwent transurethral resection of the prostate (TURP) during 1976 and 1986. OUTCOME MEASURES: Incidence and mortality rates of prostate cancer, rates of prostatectomy and TURP, and correlations between them. From the hospital data, changes between 1976 and 1986-87 in distribution of cancer stages, distribution of cases detected incidentally after surgery for suspected benign prostatic hypertrophy and average number of slides analysed per gram of tissue obtained from prostatectomy. RESULTS: The epidemiologic data showed that the age-adjusted incidence rates increased by 72% overall, an increase seen in all age groups over 60 years. The mortality rates increased by 29% overall, primarily in men over 85 years old. The prostatectomy rate increased by 55%. There were significant linear correlations between the national and provincial incidence rates of prostate cancer and the TURP rates. The chart review revealed that during 1976, 53% of the cases of prostate cancer diagnosed were localized, as compared with 75% in 1986-87 (p < 0.01). The proportion of tumours diagnosed incidentally in men undergoing TURP increased by 11%, whereas the number of procedures did not increase. Significantly more slides per gram of tissue were analysed in 1986-87 than in 1976 (p < 0.01). CONCLUSIONS: The correlations between the incidence rates of prostate cancer and those of TURP suggest that increased treatment of benign prostatic disease has led to increased detection of prostate cancer. Extrapolation of the data obtained from the chart review indicates that the increase in observed incidence rates can be attributed to an increase in the rate of localized disease and thus primarily to early detection rather than to elevated risk. However, because the rate of death from prostate cancer was elevated in elderly men, increases in exposure to unestablished risk factors cannot be ruled out.

Age Factors↗
PubMed1992

Diagnostic value of microvillus-matrix associations in tumors.

Until now microvillus-matrix associations have been reported to occur only in mesotheliomas and hence this phenomenon is thought to be of value in distinguishing mesothelioma from pulmonary adenocarcinoma. We report here the occurrence of microvillus-matrix associations in two pulmonary adenocarcinomas which reduces the value of this phenomenon in the differential diagnosis of these tumors.

Adenocarcinoma↗
PubMed1990

The respiratory effects of cobalt.

We studied seven subjects with certain manifestations of cobalt-induced lung disease. All worked with cobalt and were involved in either the production or use of hard metal. The mode of presentation varied from an acute hypersensitivity pneumonitis that cleared completely when exposure ceased to progressive severe interstitial fibrosis of the lungs. In one subject reexposure was followed by a recurrence of the symptoms. All subjects showed restrictive ventilatory impairment and a reduction of their diffusing capacity. The radiologic appearances varied greatly. While two subjects had clear roentgenograms with small lung volumes, others had a micronodular pattern or small blotchy nodular infiltrates, and one had diffuse reticulonodulation as is seen in cryptogenic fibrosing alveolitis. The pathologic appearances varied between desquamative interstitial pneumonia and overt mural fibrosis of the alveoli. Six of the seven patients had multinucleated giant cells in their biopsy specimens or bronchoalveolar lavage fluid.

Adult↗
PubMed1989

Mass fatality aircraft disaster processing.

On Dec. 12, 1985, a contract transport carrying 248 U.S. Army personnel crashed on takeoff at Gander, Nfld., Canada, killing all the passengers as well as the crew of eight. This was the worst aircraft accident in U.S. military history and, at the time was the fifth worst accident in aviation history. Cooperation between the governments of Canada and the United States allowed for the transport of all human remains to the U.S. Air Force mortuary facility at Dover AFB, DE, where they were processed, identified, and ultimately returned to their families for burial. Under ideal circumstances, any medical examiner's office or mortuary facility would be overwhelmed by a mass disaster of this magnitude. Before the arrival of the first shipment of bodies, a concerted planning effort was undertaken and the facility arranged so that remains would pass in a logical sequence through a series of 10 "work stations." This report details the process and outlines the logistics of the operations.

Accidents, Aviation↗
PubMed1988

Cystic disease of the lungs.

Cystic disease of the lung should be considered in the differential diagnosis of any patient presenting with respiratory symptoms. The most important aids available to the thoracic surgeon for the evaluation of cystic disease are history, physical examination, and chest radiograph. Confirmation of diagnosis often requires computed tomography, pulmonary and thoracic aortic angiography, and upper gastrointestinal barium series.

Adolescent↗
PubMed1987

Cryosurgical modification of the atrioventricular node: a closed heart approach in the dog.

Intraoperative modification of the atrioventricular (AV) node to prolong refractoriness could be an alternative to His bundle ablation in patients with refractory supraventricular arrhythmias. It was postulated that a cryosurgical lesion at the posterior interatrial septum in the closed heart could achieve this. An electrophysiologic study was performed in anesthetized dogs. The AV fat pad was mobilized to expose the posteroseptal region. A cryoprobe cooled to 0 to -10 degrees C was moved in the exposed region until reversible AV block indicated proximity of the AV node. The probe was then cooled to -70 degrees C for 30 seconds. Four weeks later, five dogs had a favorable result with a mean prolongation of Wenckebach cycle length of 45 +/- 7% (p less than 0.05). Two dogs had complete heart block. Decreased (one dog) or increased (one dog) duration of freezing resulted in no change and complete heart block, respectively. Histologic examination verified partial damage to the AV node with preservation of the His bundle. Thus, controlled cryoinjury to modify AV node function is feasible in the closed heart; preservation of AV conduction provides an advantage over His bundle ablation.

Animals↗
PubMed1987

Antiulcer agents. 3. Structure-activity-toxicity relationships of substituted imidazo[1,2-a]pyridines and a related imidazo[1,2-a]pyrazine.

Investigation of the interrelationship between structure, antiulcer activity, and toxicology screening data derived from a series of compounds selected from structure-activity studies directed toward identifying a successor to 3-(cyanomethyl)-2-methyl-8-(phenylmethoxy)imidazo[1,2-a]pyridine, Sch 28080 (1), has identified 3-(cyanomethyl)-2,7-dimethyl-8-(phenylmethoxy)imidazo[1,2 -a]pyridine (5), 3-amino-2-methyl-8-(2-phenylethyl)imidazo[1,2-a]pyridine (6), and 3-amino-2-methyl-8-(phenylmethoxy)imidazo[1,2-a]pyrazine (7). These analogues exhibit a combination of antisecretory and cytoprotective activity in animal models, while eliminating the adverse effects of the prototype 1. One of these, 3-amino-2-methyl-8-(phenylmethoxy)imidazo[1,2-a]pyrazine, Sch 32651 (7), has a profile meeting all criteria.

Animals↗
PubMed1987

Cardioversion and defibrillation using a catheter electrode: myocardial damage assessed at autopsy.

A technique has been described for countershock in an intensive care setting using a catheter electrode in patients with recurrent ventricular tachyarrhythmias. During defibrillation or cardioversion an electrode in the superior vena cava acts as an anode and an electrode in the right ventricular apex is the cathode. This report describes the resultant changes in the hearts of four men who died with recent, large myocardial infarcts and who had received eight to 55 countershocks of 2.5-50 joules through the catheter. Mural thrombus and/or focal endothelial hemorrhage was found in three hearts at the anode site. Thrombus was seen at the cathode site in two hearts. Myocardial necrosis, secondary to the catheter, was present in only one heart which had a 2 mm rim of granulation tissue around the distal electrode. It is unlikely that this focal area of right ventricular damage would be clinically important. We conclude, therefore, that repeated countershocks delivered through the catheter system produce little myocardial damage.

Aged↗
PubMed1987

Quantitative structural analysis of collagen in chordae tendineae and its relation to floppy mitral valves and proteoglycan infiltration.

Imbibition analysis, a polarised light microscopy technique, was used to examine the molecular organisation of collagen in normal and diseased mitral valve chordae tendineae. A single strut chorda from each of 23 valves (14 from necropsy specimens and nine from valve replacement surgery) was studied. The degree of molecular organisation of collagen in unstained 7 micron sections of the chordae was assessed by measuring the retardation of polarised light by the sample. Sections from each tendon were examined, after staining with Movat's pentachrome, for the presence of proteoglycan infiltration and classified as normal or abnormal on that basis. The imbibition analysis results were grouped accordingly. The retardation in the collagen in the seven chordae with proteoglycan infiltration was significantly lower than in the 16 normal chordae, indicating decreased molecular organisation. Five of the seven abnormal chordae with proteoglycan infiltration and decreased retardation were from patients with floppy mitral valves; the other two were from normal necropsy specimens. Although proteoglycan infiltration may not be a specific marker for floppy valve disease, its presence is associated with decreased molecular organisation of collagen in the chordae. Degradation of the ground substance bound to the collagen is the most plausible explanation for the measured optical changes.

Adult↗
PubMed1985

Controlled cryothermal injury to the AV node: feasibility for AV nodal modification.

Elective subtotal injury to the AV node-His bundle region may create a negative dromotropic effect to provide a therapeutic advantage in some patients with supraventricular tachycardia without creating complete AV block. We examined the effects of cryosurgery to the AV nodal region, varying temperature and time using a 15 mm circular cryoprobe applied directly to the canine AV node-His bundle region. Twelve dogs were anesthetized and the heart was exposed through a right thoracotomy. Electrophysiological data obtained included conduction intervals, incremental pacing, and extrastimulus testing. Under inflow occlusion, the cryoprobe was positioned over the AV node-His bundle region using anatomical landmarks and a single freeze was applied (-15 degrees C to -60 degrees C, 15 to 60 seconds). Dogs were allowed to recover for 1 month, after which time electrophysiological testing was repeated under similar conditions; then the animals were sacrificed. With probe temperatures of -60 degrees C for 15 to 60 seconds, five of six dogs experienced complete heart block with dense fibrosis observed in the AV nodal-His bundle region. After freezing with higher temperatures, the remaining seven dogs had return of atrioventricular conduction postoperatively with prolongation of AH time observed in five and marked prolongation of the Wenckebach cycle length in three of the five. We conclude that controlled cryothermal injury to the AV node-His bundle region may be useful to create a desirable negative dromotropic response without creating complete AV block.

Animals↗