The snakestone experiments. An early modern medical debate.
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Animals↗
Biomedical subjects
M Baldwin
Publications and source records attributed to M Baldwin.
Sclerosing lobular hyperplasia of the breast: imaging features in 15 cases.
OBJECTIVE: Sclerosing lobular hyperplasia is an infrequent benign lesion of the breast, defined as prominent hyperplasia of the lobules with sclerosis of the interlobular stroma. It commonly presents as a tumorlike mass clinically. Sclerosing lobular hyperplasia has been identified at biopsy at our institution with rare but increasing frequency. We reviewed the imaging features of 15 patients with biopsy-proven sclerosing lobular hyperplasia to determine if a characteristic imaging pattern could suggest this diagnosis. MATERIALS AND METHODS: The mammograms and sonograms of all women with pathologically proved sclerosing lobular hyperplasia seen between January 1986 and June 1993 were retrospectively reviewed by two of the authors who were familiar with the pathologic diagnosis. Imaging findings that led to biopsy or were present on the preoperative studies were reviewed. The study included 15 patients ranging in age from 21 to 46 years old, with a mean age of 32 years. Seven were black, and eight were white. All women had mammograms, three patients had prior mammograms for comparison, and sonography was done in all but one case. Presenting symptoms included a recently discovered breast lump in eight patients, breast tenderness in one patient, and a clear nipple discharge in one patient. The other five were asymptomatic and had screening mammograms. RESULTS: Eight patients (53%) had a well-defined mass on mammography, varying in size from 1.0 cm to 8.0 cm (mean, 3.7 cm). In one of these patients, the nodule was proved to be a fibroadenoma; sclerosing lobular hyperplasia was found only microscopically. Microcalcifications were present within the mass on mammography in one patient. Mammograms in two women showed asymmetric increased density compared with the opposite breast, and in five cases, the mammographic findings were interpreted as normal. Sonograms showed a solid, well-defined mass with either homogeneous or mixed echoes in 10 of 14 patients (71%). In only one of these nodules was acoustic enhancement present. In the other four women, sonograms were normal. No characteristic findings were identified that would suggest sclerosing lobular hyperplasia as a likely diagnosis preoperatively, and, in fact, in many cases a diagnosis of fibroadenoma was considered most probable. CONCLUSION: The imaging findings of sclerosing lobular hyperplasia are not sufficiently characteristic to distinguish the lesion from fibroadenomas and well-circumscribed carcinomas.
Adult↗
Structural clues to prion replication.
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Animals↗
Nervous system dysfunction among workers with long-term exposure to manganese.
Neurological disorders, bearing many similarities to Parkinson's disease, have been associated with environmental and occupational exposure to manganese (Mn). To document early nervous system dysfunction associated with long-term exposure to Mn, a battery of neurofunctional tests was administered to workers employed in Mn alloy production. Study participation was 95% (n = 115). A matched pair design was used; actively working men, with no history of workplace exposure to neurotoxins, were recruited from the region as referents. Matching was done on the variables: age (+/- 3 years), educational level (+/- 2 years), smoking status, and number of children. Stationary environmental sampling indicated that Mn levels varied widely (geometric means: Mn dust, 0.89 mg/m3; respirable Mn, 0.04 mg/m3). The alloy workers had significantly higher levels of whole blood Mn (geometric mean: 1.03 microgram/100 ml vs 0.68 microgram/100 ml); no differences were observed for urinary Mn. Univariate analysis (paired t test, Signed Rank and McNemar) and multivariate analysis of variance (Hotelling-Lawley statistic) revealed that the pairs differed on symptom reporting, emotional state, motor functions, cognitive flexibility, and olfactory perception threshold; verbal fluency, basic mathematics, reading capability, and attentional capacity were similar. These findings are consistent with current knowledge on brain Mn activity and suggest that manifestations of early manganism can be observed in well designed population studies, using sensitive testing methods.
Adult↗
Conversion of alpha-helices into beta-sheets features in the formation of the scrapie prion proteins.
Prions are composed largely, if not entirely, of prion protein (PrPSc in the case of scrapie). Although the formation of PrPSc from the cellular prion protein (PrPC) is a post-translational process, no candidate chemical modification was identified, suggesting that a conformational change features in PrPSc synthesis. To assess this possibility, we purified both PrPC and PrPSc by using nondenaturing procedures and determined the secondary structure of each. Fourier-transform infrared (FTIR) spectroscopy demonstrated that PrPC has a high alpha-helix content (42%) and no beta-sheet (3%), findings that were confirmed by circular dichroism measurements. In contrast, the beta-sheet content of PrPSc was 43% and the alpha-helix 30% as measured by FTIR. As determined in earlier studies, N-terminally truncated PrPSc derived by limited proteolysis, designated PrP 27-30, has an even higher beta-sheet content (54%) and a lower alpha-helix content (21%). Neither PrPC nor PrPSc formed aggregates detectable by electron microscopy, while PrP 27-30 polymerized into rod-shaped amyloids. While the foregoing findings argue that the conversion of alpha-helices into beta-sheets underlies the formation of PrPSc, we cannot eliminate the possibility that an undetected chemical modification of a small fraction of PrPSc initiates this process. Since PrPSc seems to be the only component of the "infectious" prion particle, it is likely that this conformational transition is a fundamental event in the propagation of prions.
Animals↗
Ascaris lumbricoides resulting in acute cholecystitis and pancreatitis in the Midwest.
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Acute Disease↗
The clinical application of oto-acoustic emissions in paediatric audiological assessment.
The value of otoacoustic emissions as an objective screening test for normal peripheral auditory function in infants is currently the subject of extensive and promising research. Additionally the measurement of cochlear emissions is potentially useful when children cannot be tested reliably by traditional subjective methods but confirmation of normal hearing is diagnostically important. Three groups of children are described who present such audiological dilemmas: children with non-organic hearing loss, children with severe learning difficulties and more rarely children with an abnormal auditory brainstem response who also have damage to the central nervous system. In all three groups otoacoustic emission testing was found to be diagnostically useful in determining normal peripheral auditory function thereby resolving some of the dilemmas facing paediatric audiology and ENT clinics.
Adolescent↗
Paranasal sinus cancer.
This is a review of 65 patients with paranasal sinus malignancies who were treated by radical surgery. Most patients received either pre- or postoperative radiotherapy. Twenty-nine tumours arose in the maxillary antrum, seventeen in the ethmoid labyrinth and the remainder from the vestibule, nasal septum, lateral nasal wall and vault. There were 58 epithelial cancers. The 5-year survival rate for patients with adenocarcinoma was 78%, and 70% for antral squamous cell cancer and esthesioneuroblastoma. None of the melanoma patients survived free of disease for 5 years. The 5-year survival rate for the 21 patients undergoing orbital exenteration was 50%, compared with 70% when the eye was spared. Twelve free flap revascularized tissue transfer flaps were used to reconstruct large cranial and sino-orbital defects.
Actuarial Analysis↗
Neonatal at risk screening and the identification of deafness.
From a cohort of 10,686 live births, 322 (3%) were identified as being at risk of a hearing impairment defined as moderate, or worse. These neonates were screened by measurement of auditory brainstem responses. The neonatal at risk screening programme was effective in terms of both yield and cost. The mean age at which hearing aids were fitted was 6 months in the children identified by the neonatal screen. Such a programme is both practicable and useful in a district general hospital. The yield from the neonatal programme was, however, only 43% of the total number of deaf children eventually identified from the cohort. The need to identify more deaf children by a sensitive infant distraction test screening programme remains.
Age Factors↗
Microvascular free flap in hereditary hemorrhagic telangiectasia.
A 69-year-old male patient with hereditary hemorrhagic telangiectasia presented with severe epistaxis requiring repeated transfusions. Both nasal passages were densely populated with these vascular malformations that involved the entire nasal mucosa. A total rhinotomy was performed and all the nasal mucosa and turbinates were excised. Both nasal passages were completely resurfaced with a free radial forearm skin flap. The vascular pedicle was delivered from the nasal passage via the maxillary antrum to anastomose with the facial vessels in the cheek. Following surgery the patient had no further significant epistaxis.
Aged↗
Interpersonal influence as active coping: effects of task difficulty on cardiovascular reactivity.
This study examined the effects of attempting social influence on cardiovascular reactivity. Subjects were randomly assigned to a noncontingent reward condition or one of three conditions in which receipt of a monetary reward was contingent on their ability to influence another individual through a persuasive communication. In the contingent conditions, the task was presented as either easy, difficult, or very difficult. Measures of systolic blood pressure, diastolic blood pressure, and heart rate were recorded while subjects prepared and delivered the persuasive communication (contingent conditions) or reviewed and read aloud the same statement without an incentive to influence. The contingent conditions produced significantly higher levels of systolic and diastolic blood pressure and heart rate reactivity during preparation and speaking. Further, reactivity was higher in the difficult condition than in the easy and very difficult conditions. The findings are discussed in terms of an interpersonal equivalent of traditional active coping tasks.
Adaptation, Psychological↗
Parental suspicion and identification of hearing impairment.
The contribution of parental suspicion in the original identification of a 16 year cohort of 171 children with varying degrees of hearing impairment who were screened and identified in childhood was studied. Only a quarter of the children with permanent hearing loss were identified as a result of parental concern. The presence of parental suspicion preceding the audiological diagnosis was also measured. Of the children with severe or profound deafness, the parents only suspected the presence of hearing loss in 44%. Parental suspicion was even lower for those with a mild or moderate permanent hearing loss, and for those with an otherwise symptomless conductive hearing loss caused by otitis media with effusion. Some parents did identify hearing impairment in their children, and parental suspicion should never be professionally disregarded. Most parents, however, experienced initial difficulty in recognising their children's hearing loss, even when the children were comparatively old. The study confirms the need to continue to identify deafness early by both parental vigilance and sensitive hearing screening programmes.
Age Factors↗
Anterior craniofacial resection for ethmoid and nasal cancer with free flap reconstruction.
Two surgical approaches were used for nasal and ethmoid cancers involving the anterior skull base. A craniofacial operation with the assistance of a neurosurgeon was employed when the cribriform plate was infiltrated. A frontofacial operation through the frontal sinus was preferred when the cribriform plate was radiologically intact. Thirty patients underwent radical surgery with a minimum three-year follow-up. Thirteen of 16 patients with adenocarcinoma survived. Since 1980, nine patients have had their surgical defects repaired with a revascularized tensor fascia lata muscle and skin flap. The flap is tailored to support the cranial contents, provide muscle bulk for the orbitomaxillectomy cavity, and provide skin for the face, nasal, and palatal surfaces. There were two free flap failures.
Adenocarcinoma↗
1H-n.m.r. analysis of type-2 chain lacto-gangliosides. Confirmation of structure of a novel cancer-associated fucoganglioside, alpha-NeuAc-(2----6)- beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----3)-beta-D-Galp-(1----4)-[alp ha-L- Fucp-(1----3)]-beta-D-GlcpNAc-(1----3)-beta-D-Galp-(1----4)-beta -D-Glc p- (1----1)-Cer (VI6NeuAcIII3FucnLc6Cer).
Neolacto-glycosphingolipids, substituted with alpha-NeuAc-(2----3)- and -(2----6)-linked D-Galp residues were analyzed by one- and two-dimensional 1H-n.m.r. spectroscopy at 500 MHz in 49:1 (v/v) di(2H3)methyl sulfoxide-deuterium oxide solution. For the simplest structures analyzed, nLc4Cer, IV3NeuAcnLc4Cer, and IV6NeuAcnLc4Cer, sialosylation-induced changes in shifts of terminal and subterminal core residues were interpretable in terms of existing conformational models. Chemical shifts for H-3e and H-3a of NeuAc characteristic for the type of linkage, were also determined. In addition, regularly reproducible shifts were seen for H-1 and other resonances of terminal and subterminal core residues of all structures tested. Chemical-shift correlations proved to be useful in elucidating the structure of a unique ganglioside bearing an internal beta-D-Galp-(1----4)-[alpha-L-Fucp-(1----3)]-beta-D-GlcpNAc-(1---- 3) residue ("X-trisaccharide") with an alpha-NeuAc-(2----6)-substituted terminal group.
Carbohydrate Sequence↗
Further characterization of type 2 and type 3 chain blood group A glycosphingolipids from human erythrocyte membranes.
Blood group A glycosphingolipids with slow chromatographic mobilities have been separated systematically with an improved chromatographic procedure, and their structures have been analyzed by application of a panel of monoclonal antibodies defining A determinants carried by type 1, type 2, type 3, and type 4 carbohydrate chains as well as by 1H NMR spectroscopy and methylation analysis. Of several A-active fractions, previously termed Aa, Ab, Ac, and Ad, in decreasing order of thin-layer chromatographic mobility, the third fraction (Ac) was characterized as containing one type 3 chain A component and one type 2 chain A component without branching, which have been termed type 3 chain Ab and nor-Ac, respectively. (Formula: see text). The major component present in the fourth A-active fraction (Ad) was isolated and characterized as a branched type 2 chain glycolipid formerly termed Ac. The major component in the fifth A-active fraction (Ae) was identified as a branched type 2 chain A previously termed Ad. The structures of Ac (n = 1) and Ad (n = 2) are (Formula: see text).
ABO Blood-Group System↗
Craniofacial resection for paranasal sinus cancer with free flap repair.
A combined transcranial and facial approach is recommended for antroethmoidal cancers which have invaded the cribriform plate area. This permits a complete enbloc excision of the ethmoid labyrinths. In most patients orbital exenteration was necessary because of tumour invasion. In the facial approach adequate exposure is achieved by mobilizing the entire nasal complex which is swung to the contralateral side. The surgical defect is repaired with a revascularized tensor fascia lata muscle and skin flap. The flap is tailored to support the cranial contents, provide muscle bulk for the orbitomaxillectomy cavity and skin for the face, nasal and palatal surfaces. Postoperative complications are few and most patients received their planned postoperative radiotherapy within a few weeks of the surgery. Since 1980, nine patients have been treated and six of these remain alive and free of disease.
Humans↗
Uveitis and arthritis induced by systemic injection of streptococcal cell walls.
A single injection of an aqueous suspension of group A streptococcal peptidoglycan-polysaccharide complexes (PG-PS) when injected intraperitoneally into Lewis rats induced a self-limiting bilateral uveitis with associated perpetuating polyarthritis. The uveitis was characterized clinically during the first 72 h by iritis and fibrin deposition. Acutely, there was infiltration of polymorphonuclear cells. The symptoms gradually subsided, and at the close of the experiment eyes were normally clinically and histologically. In contrast, perpetuating inflammation and severe tissue injury developed in the limb. Using an enzyme immunoassay with specificity for the group A streptococcal polysaccharide, the levels of PG-PS in tissues of animals that were killed 1 to 7 days post-injection were measured. The relative amounts of antigen in eye:limb:liver of PG-PS injected animals were 1:9:170. The differences in the amounts of antigen detected in the eye and limb may help explain the development of the acute uveitis in contrast to the perpetuating polyarthritis observed on PG-PS administration. The authors suggest that bacterial debris may act similarly in causing ocular inflammation in man.
Animals↗