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Biomedical subjects

F G Barker

Publications and source records attributed to F G Barker.

49 records · Page 3Linked to original sources
PubMed1995

The role of myometrial needle biopsies in the diagnosis of adenomyosis.

OBJECTIVE: To determine the sensitivity and specificity of myometrial needle biopsies in the diagnosis of adenomyosis uteri in vitro. DESIGN: Eight needle biopsies and 8 corresponding myometrial blocks were taken from 27 hysterectomy specimens with adenomyosis and 13 specimens with adenomyosis. Adenomyosis was graded on the basis of the depth of endometrial invasion into the myometrium: grade I, adenomyosis within the inner third of the myometrium; grade II, limited to the inner two thirds; and grade III, endometrial penetration into the outer one third of the myometrium. The sensitivity of 4 and 2 biopsies was calculated by conventional probability theory. RESULTS: Taking 8 needle biopsies from each uterus yielded sensitivities for grade I, II, and III adenomyosis of 9%, 64%, and 100% respectively, but the calculated sensitivities of two biopsies, taken at random, were only 2.3%, 20%, and 56%, respectively. There were no false-positive biopsies. CONCLUSIONS: Myometrial needle biopsy is a highly specific technique for the diagnosis of adenomyosis uteri but the sensitivity is low and dependent on the number of biopsies and the depth of adenomyosis.

Biopsy, Needle↗
PubMed1995

The molecular biology of brain tumors.

Recent years have seen rapid progress in our understanding of the molecular basis of brain tumors, particularly malignant astrocytomas. Translation of these advances from basic molecular genetics into the clinical arena is now underway. Molecular markers that correlate with prognosis in individual patients are being sought, and work is beginning on the identification of individuals who are at increased risk for developing a malignant brain tumor. Goals for the future include the development of more effective treatment strategies based on a clearer understanding of the pathogenesis of these tumors.

Adult↗
PubMed1994

False positive immunoreaction in products of conception.

False positive immunostaining for cytomegalovirus in products of conception was revealed using an avidinbiotinylated peroxidase complex. The cause was shown to be endogenous biotin. The use of a non-avidin-biotin method avoided the problem.

Abortion, Missed↗
PubMed1994

Efficacy of prophylactic antibiotics for craniotomy: a meta-analysis.

A meta-analysis of published randomized studies comparing prophylactic antibiotics to placebo in craniotomies was performed. Ten studies were examined; eight met criteria for inclusion into the meta-analysis. The analysis showed an advantage of antibiotics over placebo at the P < 10-8 level. Tests for homogeneity of effect size between the individual studies showed similar effects of antibiotic treatment between trials, despite variation in the randomization methods and antibiotic regimens used. No statistically significant difference was detected between antibiotic regimens that did or did not cover gram-negative organisms or between single- and multiple-dose regimens. Cumulative meta-analyses showed that this conclusion could have been confidently drawn by 1988, after only four of the eight eligible trials had been published. Trials published since that time have reinforced these conclusions but have not significantly altered them. Future studies should compare proposed new antibiotic regimens with one of those already demonstrated to be effective, not with a placebo.

Anti-Bacterial Agents↗
PubMed1994

Transethmoidal transsphenoidal approach for embolization of a carotid-cavernous fistula. Case report.

The authors describe a case of carotid-cavernous fistula that was not treatable by the standard interventional neuroradiological techniques of transarterial or transvenous occlusion of the fistula because access was blocked by prior trapping procedures. Access to the venous side of the fistula was gained by means of a transethmoidal transsphenoidal exposure, making it possible to embolize the lesion with coils. The details of this approach are described.

Adult↗
PubMed1993

The Massachusetts General Hospital. Early history and neurosurgery to 1939.

The early history of the Massachusetts General Hospital (MGH) is reviewed with emphasis on the development of neurological surgery. The hospital opened in 1823. Early trephinations were performed by Dr. John Collins Warren and others for treatment of trauma and epilepsy. In the 1880's, interest in brain surgery increased, and Dr. John Elliot performed several trephinations for brain tumors, three of which were witnessed by Dr. Harvey Cushing during his years at the MGH as medical student and intern. In 1911, all brain surgery was placed in the hands of Dr. S. J. Mixter. He later shared the assignment with his son, Dr. W. J. Mixter, who described herniation of the intervertebral disc with Dr. J. S. Barr and became the first Chief of the Neurosurgical Service at MGH in 1939.

Boston↗
PubMed1992

Postoperative low-dose heparin decreases thromboembolic complications in neurosurgical patients.

Thromboembolic complications are a major cause of postoperative morbidity and mortality in the neurosurgical patient. Prophylaxis with lower extremity pneumatic compression boots (PCBs) reduces the incidence of lower extremity deep vein thrombosis (DVT) but has not been shown to affect the incidence of pulmonary embolism (PE). Prophylaxis with low-dose heparin has consistently reduced the incidence of both DVT and PE in studies on general surgical patients but has not been adopted for use in neurosurgery primarily for fear of causing catastrophic hemorrhage. We report on a series of 138 consecutive adult patients who underwent major neurosurgical procedures on a general neurosurgical service at our institution. Patients were treated with intraoperative PCBs and, starting on the morning of the first postoperative day, with a regimen of 5000 U of heparin administered subcutaneously twice daily. This treatment was continued until patients were fully ambulatory. PCBs were discontinued 24 hours after the first administration of heparin. None of the heparin-treated patients suffered postoperative hemorrhage. We compared this series with a control group of 473 adult patients who had previously undergone major neurosurgical procedures on the same neurosurgical service. These patients had been treated with intraoperative and postoperative PCBs alone. The control group had a 3.2% incidence of thromboembolic complications (15 of 473; eight DVT, seven PE). Prophylaxis with PCBs plus heparin significantly (P = 0.020) reduced the incidence of thromboembolic complications: no PCBs/heparin-treated patient exhibited clinical evidence of PE or DVT (0%, 0/138). We conclude that a combination of intraoperative PCBs and postoperative low-dose heparin is a safe and effective method by which to reduce thromboembolic complications in the neurosurgical patient.

Adult↗
PubMed1990

Clinical aspects of vasospasm.

In summary, clinically significant vasospasm is characterized by several relatively consistent features. Those patients most at risk are adults, of either sex, who have had a subarachnoid hemorrhage about 4 to 9 days previously; who had a poor clinical grade on admission; and in whom a CT scan taken 24 to 48 hours after the ictus showed a thick layer of blood surrounding one or more of the major cerebral vessels. Initially afebrile, affected patients later develop a steady low-grade fever and may have an elevated WBC count, but no infectious source of fever can be found. Patients complain of worsening headache, but not as bad as the one a few days ago; the neck may feel a little more stiff. The pulse is slightly faster than usual, the blood pressure perhaps a bit higher; however, the ECG shows only "cerebral T waves." An antifibrinolytic agent may have been used. The serum sodium concentration has dropped significantly. Such patients need a more thorough examination than usual, directed toward more subtle neurologic signs, and a few extra checks during the day by both physician and nurses, so that we can apply what remedies we have when the patients are just "a little more confused," rather than later, when they are exhibiting decerebrate posturing and coma.

Humans↗
PubMed1987

Streptococcal necrotising fasciitis: comparison between histological and clinical features.

Nineteen acute and 17 subacute cases of necrotising fasciitis due to beta haemolytic streptococci are described. Excised tissue from seven and four cases, respectively, was available for histological examination. The two clinical types showed remarkable similarities, with inflammation and necrosis from epidermis to subcutaneous fat. Haemorrhage was present in variable amounts in both types. Gram positive cocci were not always identified in tissue, nor cultured, when serological tests were required to confirm the diagnosis. The only apparent difference between the acute and subacute type was the higher incidence of thrombi in some blood vessels of acute cases, whereas patent vessels or recanalized thrombus were usually found in subacute cases. This quantitative difference in the degree of thrombosis may alone be responsible for the varying clinical features and response to antibiotics.

Acute Disease↗
PubMed1982

Comparison of direct and indirect enzyme immunoassays with direct ultracentrifugation before electron microscopy for detection of rotaviruses.

A direct and an indirect enzyme immunoassay (EIA) were evaluated against a standard of electron microscopy after direct ultracentrifugation of the specimen for their performances in detecting rotaviruses. The indirect EIA had variable background activity which influenced test specificity. The indirect EIA control (test system without the detector antibody) plus a regression line (which reflected background noise) improved test specificity. However, the results of direct EIA (Rotazyme; Abbott Laboratories, North Chicago, Ill.) sensitivity (86%) and specificity (96%) were better than those of the indirect EIA in tests on 73 rotavirus-positive and 78 rotavirus-negative specimens. Endpoint titrations of purified SA-11 rotavirus showed greater sensitivity of the direct EIA test. Electron microscopy, performed after direct ultracentrifugation, and direct EIA were approximately 2 log10 more sensitive in the detection of purified SA-11 rotavirus than was electron microscopy with standard methods of unconcentrated specimen preparation. Direct EIA test are potentially sensitive, specific, and practical for the rapid detection of rotaviruses from human clinical specimens. Further studies are needed before EIA methods for detection of human rotaviruses can be equated with the level of reliability of results obtainable with sensitive electron microscopy techniques.

Animals↗
PubMedDate not supplied

Myometrial zonal differentiation and uterine junctional zone hyperplasia in the non-pregnant uterus.

Human non-gravid myometrium differentiates in response to ovarian sex steroids into a subendometrial layer or junctional zone and an outer myometrial layer. Compared to the outer myometrial layer, the junctional zone myocytes are characterized by higher cellular density and lower cytoplasmic-nuclear ratio. These structural differences allow in-vivo visualization of the myometrial zonal anatomy by T2-weighted magnetic resonance (MR) imaging. The human myometrium is also functionally polarized. Video-vaginosonography studies have shown that propagated myometrial contractions in the non-pregnant uterus originate only from the junctional zone and that the frequency and orientation of these contraction waves are dependent on the phase of the menstrual cycle. The mechanisms underlying zonal myometrial differentiation are not known, but growing evidence suggests that ovarian hormone action may be mediated through cytokines and uterotonins locally released by the basal endometrial layer and endometrio-myometrial T-lymphocytes. Irregular thickening of the junctional zone due to inordinate proliferation of the inner myometrium, junctional zone hyperplasia, is a common MR finding in women suffering from menstrual dysfunction. Preliminary data suggest that junctional zone hyperplasia is further characterized by loss of normal inner myometrial function. Although irregular thickening of the junctional zone has been associated with diffuse uterine adenomyosis, the precise relationship between subendometrial smooth muscle proliferation and myometrial invasion by endometrial glands and stroma remains to be established.

Cell Differentiation↗