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Biomedical subjects

B Lane

Publications and source records attributed to B Lane.

At least 73 records · Page 4Linked to original sources
PubMed1992

Structure-function studies in a series of carboxyl-terminal octapeptide analogues of anaphylatoxin C5a.

The synthesis and structure-activity relationships of C-terminal octapeptide analogues of anaphylatoxin C5a have been studied. The introduction of hydrophobic amino acids into the N-acetylated native octapeptide (N-Ac-His-Lys-Asp-Met-Gln-Leu-Gly-Arg-OH) (1) has led to an analogue with 100 times more activity than the native octapeptide in inhibiting the binding of 125I-labeled anaphylatoxin C5a to human neutrophil membrane receptors. The observed apparent binding Ki's for the compounds (8-10) are in the range of 1-3 microM, and they possess nearly full agonist activity, despite the fact that these analogues are one-eighth or -ninth the size of the natural ligand anaphylatoxin C5a.

Amino Acid Sequence↗
PubMed1992

Altered surface character of stretched condom latex.

A new type of imperfection in condom latex, present during moderate stretching, was observed by low magnification scanning electron microscopy. The normally smooth surface of relaxed natural latex was transformed into an accordion-like arrangement of ripples in addition to tears. A corollary experiment with Alcian blue dye placed into both stretched and unstretched condoms leaked no dye. These surface features are consistent with latex acting as a molecular barrier. The tears may represent areas of lowered mechanical resistance and raise questions concerning quality control.

Contraceptive Devices, Male↗
PubMed1992

Cytokeratin and vimentin heterogeneity in human cornea.

The body of information on cytokeratin expression in non-epithelial and epithelioid cells is steadily increasing. In this immunocytochemical study using a panel of monoclonal cytokeratin antibodies, we regularly observed cytokeratins no. 8 and 18 together with vimentin in the corneal endothelium of the human eye, but the antibodies exhibited a heterogeneous reactivity pattern. In fetal eye specimens, cytokeratins were already present at the 10th week of gestation, and disappeared at about the 22th week of fetal development. Corneal and conjunctival epithelial cells in the same specimens usually showed uniform cytokeratin 8 and 18 expression, beside the well documented presence of corneal and squamous epithelium type cytokeratins. In 2 of our 7 cases of adults, cells coexpressing cytokeratin and vimentin were observed in the corneal epithelium. The data provide another example of modulation of cytokeratin and vimentin expression, in which simplistic rules cannot be applied.

Adult↗
PubMed1992

Brain gray and white matter volume loss accelerates with aging in chronic alcoholics: a quantitative MRI study.

Magnetic resonance imaging (MRI) was used to study in vivo the brains of 49 patients with chronic alcoholism, 3 to 4 weeks post-withdrawal, and 43 normal healthy controls, all right-handed male veterans between the ages of 23 and 70 years. MRI scans were analyzed using a semi-automated procedure, which allowed the subcortical regions to be segmented into cerebrospinal fluid (CSF) and brain tissue and the cortical regions to be segmented into CSF, gray matter, and white matter. An age regression model was used to examine the effects of alcohol on brain structure, over and above that expected from the normal aging process. The alcoholics exhibited decreased tissue and increased CSF after correcting for aging. In the cortex, there was significant loss of both gray matter and white matter volume. In this sample of alcoholics, no particular cortical region was preferentially affected or spared. Furthermore, brain tissue volume loss increased with advanced age in the alcoholics. In this group of alcoholics there was no relationship between length of illness and age, i.e., the younger alcoholics had as heavy alcohol use histories as did the older alcoholics. Thus, the increased brain tissue loss with advanced age is interpreted as evidence for age-related increase in brain vulnerability to chronic alcohol abuse.

Adult↗
PubMed1992

Intranidal aneurysms in cerebral arteriovenous malformations: evaluation and endovascular treatment.

Patients with cerebral arteriovenous malformations (AVMs) have an increased risk of hemorrhage if an intranidal aneurysm is present. Angiograms from 125 patients with cerebral AVMs were evaluated, and 15 (12%) had intranidal aneurysms. All 15 patients had a history of bleeding. Five patients underwent particulate or liquid embolization before surgical excision of or radiation therapy for the AVM. All aneurysms were thrombosed at the time of embolization. Ten patients underwent radio-surgery alone. Eight of the 10 underwent angiographic follow-up (mean, 33 months); seven patients showed complete obliteration of the AVM without residual aneurysm. Histologic evaluation showed intranidal aneurysms to be thin-walled vascular structures, and they are the likely site for AVM hemorrhage. Embolization is an effective method for achieving thrombosis of the intranidal aneurysm and may be beneficial in patients undergoing radiation therapy because of a long latency period between treatment and thrombosis of the AVM.

Adolescent↗
PubMed1992

Immunohistochemical analysis of the cytokeratin expression in middle ear cholesteatoma and related epithelial tissues.

Immunohistochemical investigations were carried out to determine the pattern of cytokeratin (CK) expression in middle ear cholesteatoma and related epithelia. Using monoclonal antibodies specific for CK chains and the indirect immunoperoxidase technique, we examined 10 CK polypeptides for expression. The external stratified squamous epithelium of the tympanic membrane generally expressed CKs 5, 10, and 14. In addition, basal keratinocytes in the annular region of the pars tensa expressed CK 19 (a simple epithelium marker), while suprabasally the hyperproliferative marker CK 16 was expressed. These data reflect the unusual proliferative nature of this region. The unexpected appearance of CK 16 (known to have a limited distribution in healthy epidermis) clearly relates to its expression in the neighboring deep meatus. The medial simple epithelium of the eardrum revealed mucosal CKs 7, 8, 14, 18, and 19. Acquired cholesteatoma lesions, besides CKs 5, 10, and 14, consistently expressed CK 16 in suprabasal layers. These results constitute the first direct molecular evidence for the hyperproliferative nature of the cholesteatoma matrix. Overall, our CK data suggest that aural cholesteatoma lesions and epidermal tissue in this area are related. However, they do not explain the mechanism(s) by which the eardrum or meatal epithelia might invade the middle ear cavity. Congenital cholesteatomas expressed CKs 5, 10, 14, and 16 equally. These CK data do not support the idea of a metaplastic origin from middle ear mucosa; instead, they suggest activation of an ectodermal rest in the middle ear cavity.

Adult↗
PubMed1992

Basal-cell keratins in cervical reserve cells and a comparison to their expression in cervical intraepithelial neoplasia.

Expression of keratins 5, 14 and 17 in endocervical subcolumnar reserve cells was detected by means of immunohistochemical studies using polypeptide specific monoclonal antibodies. These particular keratins that were found among others in basal cells could also be detected to a variable extent in metaplastic and dysplastic cervical lesions. In some cases of immature squamous metaplasia all three keratin subtypes were expressed throughout the full thickness of the epithelium. In contrast, in mature squamous metaplasia a compartmentalization of these keratins was observed. Mature squamous metaplastic epithelium showed a keratin distribution pattern comparable to ectocervical squamous epithelium, with the exception of keratin 17, which was only sporadically found in the basal layer of ectocervical epithelium and was always present in the basal cells of mature squamous metaplastic epithelium. During progression of cervical intraepithelial neoplasia a clear increase in the expression of keratin 17 was observed. However, also keratins 5 and 14 were expressed. Our results demonstrate that a considerable number of premalignant lesions of the uterine cervix express the same keratins as found in the progenitor reserve cells. Lesions that lack expression of keratin 17 may form a distinct group, which are regressive in nature and do not progress into cervical cancer.

Cervix Uteri↗
PubMed1992

Keratin expression in cervical cancer.

Using a panel of 21 monoclonal and 2 polyclonal keratin antibodies, capable of detecting separately 11 subtypes of their epithelial intermediate filament proteins at the single cell level, we investigated keratin expression in 16 squamous cell carcinomas, 9 adenocarcinomas, and 3 adenosquamous carcinomas of the human uterine cervix. The keratin phenotype of the keratinizing squamous cell carcinoma was found to be most complex comprising keratins 4, 5, 6, 8, 13, 14, 16, 17, 18, 19, and usually keratin 10. The nonkeratinizing variety of the squamous cell carcinoma expressed keratins 6, 14, 17, and 19 in all cases, usually 4, 5, 7, 8, and 18, and sometimes keratins 10, 13, and 16. Adenocarcinomas displayed a less complex keratin expression pattern comprising keratins 7, 8, 17, 18, and 19, while keratin 14 was often present and keratins 4, 5, 10 and 13 were sporadically found in individual cells in a few cases. These keratin phenotypes may be useful in differential diagnostic considerations when distinguishing between keratinizing and nonkeratinizing carcinomas (using keratin 10, 13, and 16 antibodies), and also in the distinction between nonkeratinizing carcinomas and poorly differentiated adenocarcinomas, which do not express keratins 5 and 6. Keratin 17 may also be useful in distinguishing carcinomas of the cervix from those of the colon and also from mesotheliomas. Furthermore the presence of keratin 17 in a CIN I, II, or III lesion may indicate progressive potential while its absence could be indicative of a regressive behavior. Because most carcinomas express keratins 8, 14, 17, 18, and 19, we propose that this expression pattern reflects the origin of cervical cancer from a common progenitor cell, i.e., the endocervical reserve cell that has been shown to express keratins 5, 8, 14, 17, 18, and 19.

Adenocarcinoma↗
PubMed1991

Identification and synthesis of a receptor binding site of human anaphylatoxin C5a.

C5a is a 74 amino acid polypeptide that likely plays an important role in the pathogenesis of a number of inflammatory diseases. Therefore, the discovery of a C5a antagonist is of considerable therapeutic interest. A series of peptides designed to survey various regions of the molecule was synthesized by solid-phase peptide synthesis and evaluated for receptor-binding activity with polymorphonuclear leukocyte membranes. The C-terminal octapeptide (Ac-His-Lys-Asp-Met-Gln-Leu-Gly-Arg-OH) was identified as the smallest fragment which possessed reasonable C5a receptor binding activity.

Amino Acid Sequence↗
PubMed1991

Inflammatory pseudotumor of the choroid plexus in Sjögren's disease.

We report an unusual case of inflammatory pseudotumor of the choroid plexus of the right lateral ventricle, manifesting as an intraventricular mass and causing unilateral hydrocephalus in a 48-year-old man who suffered from Sjögren's disease and subacute cutaneous lupus erythematosus. The lesion obliterated the normal choroidal architecture by a mixed chronic inflammatory process that was associated with reactive connective tissue changes. Immunohistochemical studies showed no light-chain restriction in the cells, and residual islands of transthyretin-positive epithelial cells were identified, implicating the choroid plexus origin of the mass.

Cerebral Ventricle Neoplasms↗
PubMed1991

Combined (team) approach to hemangioma management: arteriography with superselective embolization plus YAG laser/sapphire-tip resection.

Thirteen patients have been treated over a 2-year period utilizing a team approach between the radiology and surgical services. Initial diagnostic evaluation is directed at determining the size and anatomic extent of the hemangioma; clinical assessment of coagulation and hemodynamic status is also performed. Arteriography with superselective embolization precedes the surgical procedure, usually by 24 hours. The YAG laser with contact sapphire-tip scalpels is then utilized for resection and reconstruction of the hemangioma. Total removal of hemangioma was achieved in 9 of 13 patients, and partial or subtotal removal was achieved in the remainder. Blood loss and complications were minimal.

Adolescent↗
PubMed1991

Bubble cells: renal tubular cells in the urinary sediment with characteristics of viability.

The urinary sediment was examined by light microscopy in 65 consecutive inpatients with renal insufficiency (not due to pre- or postrenal factors) referred to a nephrology consult service for evaluation. In the 60 patients in whom a single diagnosis was reached, the sediments of 34 (57%) contained an easily recognized cell, which we have called the "bubble cell". These cells were bizarre, large cells with a single nucleus, which appeared to contain one or more fluid-filled vesicles. Bubble cells were most prevalent in the sediment of patients with acute tubular necrosis but were also seen a variety of other renal diseases. In most patients with acute tubular necrosis, the sediment also contained "normal"-appearing renal tubular cells, muddy brown casts, and oval fat bodies which were indistinguishable from those seen in the nephrotic syndrome. By electron microscopy, the bubble cells appeared to be vacuolated renal tubular epithelial cells, which had characteristics of viable cells. Most bubble cells excluded the vital dye Trypan blue, whereas the normal-appearing renal tubular cells were typically strongly positive. It was concluded that bubble cells, often accompanied by oval fat bodies, are commonly present in the sediment of patients with acute tubular necrosis as well as many other types of renal disease. Most cells which would be classified as "normal" renal tubular cells in these sediments are dead. In contrast, the findings suggest that the bubble cell represents an injured but viable renal tubular cell. The frequent finding of oval fat bodies in the same sediments suggests that the oval fat body is also produced by tubular cell injury.

Acute Kidney Injury↗
PubMed1991

Gliofibroma. Case report.

The case history of an infant with a large gliofibroma is presented. Gliofibromas are rare mixed glialmesenchymal tumors that have been poorly characterized. The computerized tomography appearance and a detailed light and electron microscopic description are presented, along with immunoperoxidase studies of this tumor. This case is compared with gliofibromas described elsewhere in the literature.

Brain Neoplasms↗
PubMed1991

Dunaimycins, a new complex of spiroketal 24-membered macrolides with immunosuppressive activity. III. Immunosuppressive activities of dunaimycins.

The immunosuppressive effects of the dunaimycins, a new complex of spiroketal 24-membered macrolides, were compared to cyclosporin A, ascomycin, and rapamycin. Each dunaimycin was a potent inhibitor of the mitogenic response observed in mixed murine splenocyte or human leukocyte cultures, and like immunosuppressive drugs these compounds were relatively less potent inhibitors of the constitutive proliferation of murine EL4 thymoma cells. Dunaimycin D4S showed no selectivity in inhibiting the mitogenic response of spleen cells to concanavalin A, pokeweed mitogen, lipopolysaccharide, or phytohemagglutinin. Cyclosporin A and ascomycin did not inhibit interleukin 2 dependent proliferation, whereas the dunaimycins and rapamycin blocked the uptake of [3H]thymidine in mixed cultures supplemented with exogenous interleukin 2. In addition, dunaimycin D4S had no apparent affinity for cyclosporin A or FK-506 immunophilins. Although the dunaimycins inhibited the activity of Na+, K(+)-ATPase, inhibition of this enzyme appeared insufficient to explain the biological activity of these new macrolides. Over a narrow concentration range, dunaimycin D4S showed in vivo immunosuppressive activity in the murine popliteal lymph node hyperplasia model.

Animals↗
PubMed1991

Laparoscopic cholecystectomy: a hundred consecutive cases.

Laparoscopic cholecystectomy is a new, minimaly invasive technique for removing the gallbladder which has several advantages over the traditional laparotomy cholecystectomy. We reviewed our initial experience with 100 consecutive patients in whom laparoscopic cholecystectomy was attempted. The indications for operation were biliary colic, chronic cholecystitis, acute gallbladder and gallstone pancreatitis. Laparoscopic cholecystectomy was successfully performed in 87 patients. Anaesthesia time was 144 +/- 52 min. There was no mortality while overall morbidity was 14%. One patient had a retained common bile duct stone. Postoperative hospital stay was 4.1 +/- 2.2 days and the mean time to full activity in a random sample of 25 patients was 13.7 +/- 11.7 days. Laparoscopic cholecystectomy is a safe effective procedure which removes the gallbladder. We suggest that this technique be considered in all patients undergoing cholecystectomy.

Adolescent↗
PubMed1990

Localization of collagenase at the basal plasma membrane of a human pancreatic carcinoma cell line.

We have recently presented biochemical evidence for collagen and gelatin degrading activities associated with plasma membranes of various human cancer cell lines. In this report we describe the localization of interstitial collagenase at the basal plasma membrane of the human pancreatic cancer cell line RWP-I, using immunofluorescence and ultrastructural immunogold labeling techniques. Collagenase was expressed on the extracellular face of the plasma membrane. Furthermore, the immunogold labeling was concentrated on the long, finger-like microvillous projections typically seen on the basal cell surface, while the short, brush-like projections characteristic of the apical cell surface were unlabeled. When the cytoplasmic face of the membrane was made accessible, the number of reactive sites increased markedly, indicating a high concentration of enzyme at the inner surface of the plasma membrane. When plasma membrane fractions of RWP-I cells were prepared by differential centrifugation, high salt washes virtually failed to extract collagenase activity from the membrane, while detergent extraction with n-octyl glucoside, a detergent used in the purification of integral membrane proteins, yielded soluble collagenase activity. When detergent extracted membrane fractions were passed over an anticollagenase immunoaffinity column, collagenase was specifically bound, as demonstrated by the TCA and TCB degradation of type I collagen by the bound material. Gelatinolytic activity did not bind to the column. Furthermore, immunoprecipitation of 125I-labeled detergent extracts of tumor membranes yielded a single Mr 55,000 band consistent with the zymogen form of the connective tissue collagenase. These morphological and biochemical findings suggest that collagenase is a tightly associated component of the basal plasma membrane, where it occupies a strategic location for directional proteolysis during cell migration and invasion.

Cell Membrane↗