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Biomedical subjects

M A Weinstein

Publications and source records attributed to M A Weinstein.

At least 19 recordsLinked to original sources

Transanal hemorrhoidal dearterialization is an alternative to operative hemorrhoidectomy.

BACKGROUND: Transanal hemorrhoidal dearterialization (THD), a new approach for patients who would otherwise require an operative hemorrhoidectomy, accomplishes hemorrhoidal symptom relief with far less postoperative pain than an operative hemorrhoidectomy. METHODS: THD, an ambulatory procedure, employs a specially designed proctoscope coupled with a Doppler transducer to allow identification and suture ligation of the hemorrhoidal arteries. RESULTS: Sixty patients between ages 22 and 87 were treated. Bleeding was fully corrected in 88%, protrusion in 92%, and pain in 71%. Two patients (3%) failed to improve with THD. Complications included pain resulting in greater than 2 days loss of work in 5 patients, postoperative perirectal thromboses developed in 4 patients, and an anal fissure developed in 1 patient. CONCLUSIONS: THD was an effective alternative to operative hemorrhoidectomy. It may be the only option for patients where an operative hemorrhoidectomy is contraindicated because of incontinence.

Adult↗

Postoperative spinal wound infection: a review of 2,391 consecutive index procedures.

Postoperative infection remains a troublesome but not uncommon complication after spinal surgery. Most previous reports, however, are small or involve cases with more than one surgeon often at different institutions. This study represents a single surgeon's 9-year experience with postoperative infection at one institution. The authors describe the features of wound infection after spinal surgery with reference to diagnosis, microbiology, and treatment and they describe a protocol for effective management of postoperative spinal wound infection. The records of the senior author (F.P.C.) during a 9-year period for cases of postoperative wound infection were reviewed. Of 2,391 operative procedures, 46 cases of wound infection were identified, yielding an overall infection rate of 1.9%. Patients' preoperative risk factors, original diagnosis prompting the surgery, onset of infection, presentation, treatment, and outcome were analyzed. The mean age of the 23 men and 23 women was 57.2 years. The preoperative diagnoses included lumbar degenerative scoliosis or spinal stenosis in 28 cases, disk prolapse in 8 cases, metastatic disease in 4 cases, degenerative disk disease in 1 case, and a group of 5 miscellaneous cases. Seventeen (37%) of the patients underwent at least one previous spinal surgery at the same site. Twenty-three patients had a fusion, of whom 22 also had instrumentation. Forty-three (93%) of the patients had significant wound drainage after an average of 15 days (range, 5-80 days). The other three patients were examined approximately 2 years after the surgery. Fourteen of the patients also had pyrexia (temperature >37.5 degrees C) at presentation. Staphylococcus aureus alone was cultured in 29 patients, whereas another six patients had a different single organism. In nine patients, more than one organism was cultured during their hospital stay. Surgical treatment included primary closure in only seven patients, with most undergoing wound drainage and debridement followed by delayed closure. Instruments were removed in the three patients with late presentation who had solid fusion at operation. Viable bone graft and instrumentation were left in situ in all patients who were seen before fusion. All wounds healed without sequelae, except for three that required flap closure. Pseudarthrosis was noted in three patients after more than 1 year of follow-up in this series. Postoperative spinal wound infection is a potentially devastating problem. In this series, infection was more common in patients undergoing fusion with instrumentation and in patients with cancer metastatic to the spine. An aggressive surgical approach, including repeated debridement followed by delayed closure, is justified. Instrumentation may be safely left in situ to provide stability for fusion.

Diskectomy↗

Carcinoma arising in anorectal fistulas of Crohn's disease.

PURPOSE: Anorectal fistulas are commonly associated with Crohn's disease. Carcinoma arising in an anal fistula in the absence of Crohn's disease occurs rarely. Carcinoma arising in an anorectal fistula of Crohn's disease is likewise rare and is the subject of this article. METHODS: We have seen eight cases in seven patients. Four of these were squamous carcinoma and three were adenocarcinoma. Details of these seven patients are presented. RESULTS: Two deaths in the four patients with squamous carcinoma and one in the two patients with adenocarcinoma with adequate follow-up suggest a poorer prognosis in both types of malignancy than when these lesions occur without Crohn's disease. CONCLUSION: Carcinoma does arise in the midst of the anorectal fistulas and abscesses of Crohn's disease. Carcinoma arising in a Crohn's disease fistula can be very difficult to diagnose. Examination may be limited by pain, stricture, or induration of the perianal and perineal tissues. Examination under anesthesia can also overlook the lesion. Diagnostic examination under anesthesia yields increases with biopsies or curettage of the fistulous tracts.

Adenocarcinoma↗

EBV-associated anorectal lymphomas in patients with acquired immune deficiency syndrome.

Primary lymphomas of the gastrointestinal tract represent 9% of all non-Hodgkin lymphomas, and of these only 3% arise in the rectum or anus. In contrast to their rare occurrence in the general population, the incidence of anorectal lymphomas in patients with acquired immune deficiency syndrome (AIDS), particularly homosexual patients, may be as high as 26% as reported in our own series of AIDS-associated lymphomas. To determine the characteristics of this entity, we studied 15 cases of primary anorectal lymphoma in AIDS patients and compared them with four cases of anorectal lymphoma unrelated to AIDS. The cases in our study were also compared with the reports of rectal lymphoma in the medical literature over the past 30 years. In the present series, the AIDS patients were all male with a median age of 34 years, human immunodeficiency virus (HIV)-positive, with homosexuality as the main risk factor. The four non-AIDS patients included a woman and had a median age of 66.5 years. Histologically, the anorectal lymphomas in AIDS patients were all high grade, predominantly immunoblastic, and polymorphous. In the non-AIDS patients, only two of four lymphomas were high grade, including one Burkitt type. All tumors were of B-cell phenotype. In the AIDS-associated anorectal lymphomas, the presence of Epstein-Barr virus (EBV) in a latent form was demonstrated by an abundance of Epstein-Barr-encoded RNA (EBER) in 14 of 15 cases and latent membrane protein (LMP) in four cases. All anorectal lymphomas unrelated to AIDS were negative for EBV. The unusual anorectal location of AIDS-associated lymphomas is explainable by the high incidence of preceding traumatic lesions and chronic infections in the area. As a result, EBV-carrying B cells may be attracted to the field providing the cell population that, under the conditions of immune deficiency, is able to give rise to high-grade lymphomas.

Acquired Immunodeficiency Syndrome↗

A method to communicate patient preferences about medically indicated life-sustaining treatment in the out-of-hospital setting.

OBJECTIVE: Patient preferences for life-sustaining treatment are frequently unknown at critical moments, which often results in clinicians providing treatment that is not medically indicated and/or may not be consistent with patient desires. A consortium of Oregon health care professionals developed the Medical Treatment Coversheet (MTC) to standardize documentation of patient preferences in the out-of-hospital setting by having corresponding physician orders available at the patient's location. We describe a unique process of development, evaluation, and implementation of the MTC. DESIGN: First, we conducted focus groups of providers to help draft the MTC. Second, the accuracy of MTC interpretation was determined by cohorts of acute and long-term care providers by indicating their treatment approach to three hypothetical written scenarios. They responded to the same scenarios twice, with and without the MTC. Responses were compared with each other and with ideal responses (most medically appropriate and in agreement with patient preferences) as defined by an expert panel. Finally, we are instituting pilot projects and developing a plan for statewide voluntary implementation of the MTC. SETTING: Urban and rural long-term care facilities and emergency medical service systems in Oregon. PARTICIPANTS: Focus groups included 28 general internists practicing in urban and rural settings and five nurses working in a long-term care facility. In addition, 87 providers (19 primary care physicians, 20 emergency physicians, 26 paramedics, and 22 long-term care nurses) participated in the evaluation of the form by responding to hypothetical scenarios. Providers in long-term care facilities in both an urban and rural area helped with pilot implementation of the MTC. Use of the MTC in noninstitutional settings was not evaluated. MAIN OUTCOME MEASURES: Suggestions from focus groups were incorporated into the form. For the hypothetical scenario responses, ideal appropriateness scores were analyzed, with a total possible score of 30 for each acute care provider and 15 for each long-term care provider. Statistically significant differences were determined using a paired t test. We report the experience of providers who helped with the pilot implementation of the form. RESULTS: Focus groups would use the MTC and believed it would be useful for their patients. Comparing responses to the hypothetical scenarios without the MTC to those with the MTC, 37% of treatment decisions changed for acute care and 29% changed for long-term care providers. Changes were attributable overwhelmingly to withholding treatments consistent with patient preferences. Compared with the ideal, decisions were more appropriate for all specific treatments across all scenarios and clinician groups with the MTC, with one exception: some advanced emergency treatments were withheld inappropriately by 18% of acute care providers with the MTC, (chi-square = 15.94, P < .0001). For all scenarios combined, appropriateness scores increased significantly with the MTC for both acute care (16.4 to 22.3, P < .0001) and long-term care providers (8.8 to 12.2, P < .0001). Overall, providers helping with the pilot implementation were satisfied with the document, organizational endorsements, and available informational resources. CONCLUSION: We describe our process for development, initial evaluation, and implementation of the MTC. In clinical scenarios overall, the MTC improves the appropriateness of clinicians' decisions about life-sustaining treatments. We are planning statewide implementation of the MTC after appropriate education of clinicians.

Advance Care Planning↗

Diffuse bilateral cerebral astrocytomas with atypical neuroimaging studies.

The authors describe the clinical behavior of eight patients with cerebral astrocytomas, in whom computerized tomography (CT) or magnetic resonance (MR) imaging of the brain was characterized by diffuse bilateral cerebral hemisphere tissue density abnormalities and minimal focal mass effect. Five patients were newly diagnosed, and three others had been treated for focal low-grade astrocytoma. Histological diagnoses included anaplastic astrocytoma (three patients), low-grade astrocytoma (three patients), glioblastoma (one patient), and gliosis with later development of glioblastoma (one patient). In five patients, brain tumor was not suspected from the neuroimaging studies, the findings of which were mistaken for radiation leukoencephalopathy, vasogenic edema, or multiple sclerosis. Serial CT scans or MR images undertaken over intervals of 3 to 184 weeks showed progression of abnormal tissue densities in seven patients and multifocal contrast-enhancing masses developed on CT scan in two patients. An autopsy in each of four patients showed diffuse cerebral infiltration by astrocytoma. It is concluded that neuroimaging studies in some patients with diffusely infiltrating cerebral astrocytoma are atypical for neoplasm and can be mistaken for other diseases, especially those that predominantly affect cerebral hemisphere white matter.

Adolescent↗

Spontaneous direct carotid-cavernous fistula in childhood.

We report the occurrence, surgical treatment and long-term follow-up of a spontaneous, direct carotid-cavernous fistula in a child. It is the third angiographically documented, spontaneously occurring fistula to be reported in this age group and the first to arise directly from the internal carotid artery based on our review of the literature. Although our patient required fistula closure, other reported fistulae were nonprogressive and did not require treatment. The communication between the internal carotid artery and the cavernous sinus was left sided while the contralateral eye was proptotic. The clinical features, selected hemodynamic characteristics, and treatment of carotid-cavernous fistulas are reviewed.

Arteriovenous Fistula↗

Estramustine and estrone analogs rapidly and reversibly inhibit deoxyribonucleic acid synthesis and alter morphology in cultured human glioblastoma cells.

Estramustine is an estradiol-based agent that has been shown to accumulate in human glioma cells, resulting in a concentration-dependent alteration in cell size and shape within minutes and an inhibition of proliferation over 3 to 6 days. We evaluated human glioblastoma cultures with [3H]thymidine incorporation assays to determine estramustine's early effects on deoxyribonucleic acid synthesis in these tumors. Because estramustine shares a common structural motif with other antimicrotubule drugs, we synthesized four A-ring conjugates of estrone that contained a carbamate moiety but lacked nitrogen mustard. These analogs were examined by [3H]thymidine incorporation and compared with vinblastine. Greater than 70% inhibition of [3H]thymidine incorporation occurred within 1 hour of treatment with estramustine at 10(-5) mol/L, which increased to 80% inhibition at 4 hours. Ethyl carbamate JE208 was nearly as effective as estramustine in inhibiting deoxyribonucleic acid synthesis, and both were more effective than vinblastine. The inhibitory effects of estramustine and estrone analogs were reversible; vinblastine was not reversible. Although estramustine and JE208 induced similar antiproliferative and morphological changes in glioblastoma cells that persisted for at least 4 days, there was a modest recovery of morphology and thymidine incorporation with JE208 after prolonged treatment. The common findings with estramustine and JE208 suggest that these agents may have a similar mechanism of action and form the basis for the investigation of new agents that may rapidly and reversibly inhibit glioblastoma.

Brain Neoplasms↗

Precise anorectal sphincter dilatation--its role in the therapy of anal fissures.

For the past 20 years, internal anal sphincterotomy has generally been considered to be the standard operation for an anal fissure. We sought an alternative form of treatment because of the wound complications inherent in this operation. Anal dilatation, precisely performed with a Parks' retractor opened to 4.8 cm or with a 40-mm rectosigmoid balloon, has been found to cure successfully the fissure in 93 percent and 94 percent, respectively, of each group and to be associated with fewer complications.

Adult↗

Effects of neonatal exposure to the antiprogestin mifepristone, RU 486, on the sexual development of the rat.

RU 38486 (RU 486, mifepristone) is a potent progesterone receptor antagonist that has been used in humans in the pharmacologic induction of abortion. The effects of exposure to RU 486 during the neonatal period of the rat has not been previously reported. We examined the consequences of such exposure in the context of sexual development. Long-Evans rat pups were subcutaneously injected with either 100 micrograms RU 486, 300 micrograms RU 486, 500 micrograms progesterone (P), or 50 micrograms testosterone propionate (TP) in 0.05 ml sesame oil, or oil vehicle alone within 8 hours of birth, and 24 and 48 hours later. Treatment with either dose of RU 486 significantly advanced the onset of vaginal opening in females and attenuated defeminization of the lordosis response measured in males castrated as adults. As expected, TP-treated subjects were masculinized and defeminized, with females displaying fused vaginas and neither males nor females demonstrating lordosis behavior. Treatment with P caused no significant alterations in either the timing of vaginal opening or sexual behavior. These results indicate that RU 486 has clear developmental effects in the rat. Since this may well be a result of progesterone receptor blockade, further research is needed to clarify the processes involved.

Animals↗

Facilitation of receptive behavior in estrogen-primed female rats by the anti-progestin, RU 486.

The progestin receptor antagonist RU 38486 (henceforth referred to as RU 486) was tested for facilitative effects on female receptive behavior in ovariectomized Long-Evans rats primed with 2 micrograms estradiol benzoate (EB). RU 486 (0, 0.5, 1.6, or 5.0 mg) was administered 48 hr after estrogen priming. The lordosis quotient (LQ) and lordosis score (LS) were assessed 4 hr after RU 486 administration in a standardized test consisting of a 10-mount test by a stimulus male. A significant dose effect was found by both LQ and LS, with those subjects receiving 5 mg of RU 486 being significantly more receptive than vehicle control animals. Thus RU 486 acted as a weak progestin agonist under testing conditions typical for assessment of progestin facilitation of female sexual behavior in rats. Low levels of proceptive behavior (hops and darts) were seen in a minority of the tests, and did not vary systematically as a function of the dose of RU 486 administered. We also examined the effects of RU 486 given before progesterone (P) on receptivity in a blocking paradigm and confirmed previous reports that the antagonist significantly attenuates facilitation of sexual behavior when given in combination with P. A progestin receptor assay of the cytosols of the hypothalamus-preoptic area in estrogen-primed female rats treated with 5 mg RU 486 revealed a significantly greater depletion of available cytosolic P receptors than when rats were treated with a similarly facilitating dose of P (100 micrograms). The results suggest a possible dual mode of action for RU 486--a weak, receptor-mediated agonistic effect on sexual behavior when given alone to estrogen-primed rats, and a competitive blocking effect on receptivity when administered with P.

Animals↗

Intracranial chemical-shift artifacts on MR images of the brain: observations and relation to sampling bandwidth.

The purpose of this study was to evaluate the presence of chemical-shift artifacts on cranial MR and to illustrate the interrelationship among chemical-shift artifacts, variable acquisition parameters, and field strength. Measurements of chemical-shift artifacts were performed on scans obtained from a volunteer imaged in a 1.5-T General Electric system at bandwidths of 8, 16, and 32 kHz, using a 24-cm field of view and an 8-kHz bandwidth with a 48-cm field of view. Chemical-shift displacements at 8 kHz were 6.6 and 14.2 mm at the respective fields of view. Retrospective review was also performed in 77 cases of cranial MR performed on a 1.4-T Technicare unit for the presence and source of chemical-shift artifact on spin-density and T2-weighted images. Most data reviewed showed no significant interference of chemical-shift artifacts on cranial images. An artifactual subdural fluid collection was a common artifact (n = 30/77). When present, this was due to shift of fat signal from subcutaneous tissues onto the brain in patients younger than 10 years old (n = 4/10) and correlated with the distance between brain and subcutaneous fat of less than the linear value of the chemical shift. When this artifact was present in adults (n = 25/67), it was due to shift of the medullary fat signal across the inner table of the skull. The latter also occurred in one child under 10. Apparent location shifts, consistent with the displacement expected from the chemical-shift artifact, were noted in five of five cases of intracranial lipoma. In one of these, the chemical-shift artifact disguised the presence of a large associated vessel. The method of calculating the linear displacement of chemical-shift artifact is reviewed, and the interrelationship of machine parameters and chemical-shift artifact is illustrated. Chemical-shift artifact increases proportionally with field strength and field of view. Increasing the bandwidth to decrease chemical-shift artifact has a resultant penalty in signal to noise but allows a lower time to echo. A lower time to echo can also be accomplished without increasing the bandwidth if asymmetric sampling is used. Awareness of the relationships among chemical-shift artifacts, acquisition parameters, and field strengths can result in a more tailored examination when the chemical-shift artifact is going to be a significant factor. In addition, interpreter error can be avoided by awareness of these relationships when reviewing images from outside institutions.

Adolescent↗

Correlation between magnetic resonance imaging and surgical findings in the tethered spinal cord.

Between October 1982 and August 1987, 20 patients underwent magnetic resonance imaging (MRI) and subsequent surgical release of a tethered spinal cord. The tethering was caused by a thick filum terminale in 6 patients. On MRI scans, the conus medullaris was at L4 in 2 patients, at L2 in 3 patients, and the filum terminale appeared thick in 1 patient. The spinal cord was tethered to an intradural lipoma correctly demonstrated by MRI in 6 patients. Increased epidural fat was misdiagnosed as an intradural lipoma in one patient and a lipomatous stalk was not identified in 2 other patients. Scar tissue resulting from repair of a meningocele had tethered the cord in the remaining 8 patients. On MRI scans, the conus medullaris was located between L3 and S3; in 5 of the patients, scar tissue was apparent on the MRI scan. This correlative study supports the use of MRI as the initial, and possibly the only, imaging modality when a tethered spinal cord is suspected. Improved or more recent MRI techniques will help demonstrate these anomalies better.

Adolescent↗

Magnetic resonance imaging of disturbances in neuronal migration: illustration of an embryologic process.

Twenty-three cases of suspected congenital anomalies involving disorders of cortical proliferation, migration or cortication were retrospectively collected over an 18 month period. Pathologic confirmation was present in five cases. The theoretical sequential stages of cortical development are discussed as keys to the interpretation of MR images of anomalies resulting from arrest of the developmental process. MRI is the imaging modality of choice for suspected defects of cortex formation since it distinguishes gray from white matter, delineates the corticomedullary junction, records details of cortical surfaces, detects abnormal white matter, identifies heterotopias and records unrelated congenital abnormalities. Histopathologic confirmation of two cases of isolated heterotopia and three cases of polymicrogyria were available. Comparative images of MR, CT and pathologic specimens are presented.

Brain↗

High-signal periventricular lesions in patients with sarcoidosis: neurosarcoidosis or multiple sclerosis?

The vast majority of periventricular abnormalities visualized with MR imaging in patients less than 50 years old represents multiple sclerosis (MS) lesions. There are many other causes of periventricular lesions, most of which can be differentiated from MS on the basis of history and physical or MR findings. Five cases of biopsy- or Kveim test-proved sarcoidosis with MR findings consistent with MS are reported. Each of these patients, diagnosed as having sarcoidosis, had symptoms identical to those seen in MS. Although these patients have not had histologic characterization of the intraparenchymal lesions seen on MR, they illustrate the difficulty of differentiating sarcoidosis with CNS involvement from MS in some patients on the basis of clinical, radiographic, electrodiagnostic, or CSF testing. This series contributes to a growing body of evidence that neurosarcoidosis probably should be included in the differential diagnosis of isolated periventricular lesions in patients less than 50 years old.

Adult↗

MR imaging characteristics of tuberculous spondylitis vs vertebral osteomyelitis.

Retrospective evaluation was made of four patients with tuberculous spondylitis who had been studied by MR with T1- and T2-weighted images in the sagittal plane and spin-density-weighted images in the axial plane. Evaluation was made of the distribution of abnormal signals within the body and posterior elements of the vertebrae, the intervertebral disk, and the associated paraspinal and epidural areas. In two of the cases, three-level involvement was seen with noninvolvement of intervening disks; metastases were misdiagnosed. One patient had anterior/inferior erosion of the vertebral body without visualization of the disk. The last patient had the more typical MR characteristics of intervertebral disk infection. Plain film examination showed only degenerative changes in three of the four cases. MR revealed more extensive involvement than the plain films did. Involvement of the posterior element and posterior vertebral body was prominent in three of the four cases. This is a significant finding since these patients are more likely to have neurologic symptoms and require laminectomy. Follow-up examinations in two cases showed increased signal on T1-weighted images, suggesting infiltration of hemopoietic marrow with fat, as has been described for degenerative osteoarthritis. The anatomy of the microcirculation of the vertebral body is related to the patterns of vertebral osteomyelitis, and discrepancies can be seen between the findings in our cases and the MR criteria previously noted for pyogenic vertebral osteomyelitis. The MR findings in our patients generally were more typical of neoplasm than of infection. These findings may reflect the characteristics of the tuberculous organism relative to the age-dependent pattern of vertebral microcirculation. Correct diagnosis of tuberculous spondylitis in young to middle-aged adults requires correlation of MR and clinical findings.

Adolescent↗

Gd DTPA. Clinical efficacy.

Both the diagnostic accuracy and sensitivity of the MRI diagnosis of central nervous system neoplasms appear to be improved by the administration of a paramagnetic contrast agent, Gd DTPA.

Brain Neoplasms↗