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Biomedical subjects

J Lombardi

Publications and source records attributed to J Lombardi.

At least 19 recordsLinked to original sources
PubMed2001

Optimization of force constants with an Urey-Bradley force field avoiding normal mode crossings.

We present a method that simplifies the refinement of force constants in normal mode calculations and makes the results more reliable. The method avoids normal mode crossings by constraining the force constants during refinement. It was tested with pyrrole, imidazole, benzene, pyridine, pyrimidine, aniline and adenine using a Urey-Bradley force field. The global error of the frequency fit for these molecules was 0.61%. The method reproduced with fewer parameters the accuracy of similar calculations of the single ring aromatic compounds. It improved the accuracy and isotopic shifts of previous empirical calculations of adenine by 40%. The C-C and C-N stretchings differed by less than 7% from the values of force constant-bond length empirical relations.

Adenine↗
PubMed2001

Abnormal duplex findings at the proximal anastomosis of infrainguinal bypass grafts: does revision enhance patency?

Using color duplex ultrasound (CDU) surveillance of autogenous infrainguinal bypasses, a peak systolic flow velocity (PSFV) ratio of greater than 3 to 1 within the graft relative to adjacent PSFV has been accepted as predicting significant stenosis mandating revision. At the proximal anastomosis, where significant vessel diameter differences and turbulent flow exist, the validity of these criteria is less clear. Our purpose was to review our experience with proximal anastomotic abnormalities in a CDU surveillance protocol. Routine CDU surveillance for all infrainguinal bypass gratis consisted of evaluation in an accredited vascular laboratory at 1 month postoperatively, every 3 months for the first year, every 6 months in the second year, and annually thereafter. Grafts with a PSFV ratio of >3 at the proximal anastomosis on any CDU study were included in this review. From our results we conclude that currently accepted CDU criteria for graft-threatening stenosis may not be valid for abnormalities at the proximal anastomosis of infrainguinal grafts. Regression of these abnormalities is common. Better CDU criteria are needed for predicting not only severity of proximal anastomotic stenosis but also likelihood of graft thrombosis.

Adult↗
PubMed2001

Has arteriography gotten a bad name? Current accuracy and morbidity of diagnostic contrast arteriography for aortoiliac and lower extremity arterial disease.

Recently, contrast arteriography has been challenged as the diagnostic test of choice for lower extremity arterial disease because of its associated morbidity and questionable accuracy in identifying suitable distal outflow arteries. The purpose of this report was to analyze our experience to determine if these concerns were justified. We reviewed 500 consecutive contrast arteriograms performed at our hospital for aortoiliac and lower extremity arterial disease between November 1994 and November 1998. Arteriograms performed in conjunction with therapeutic procedures such as balloon angioplasty, stent placement, and thrombolysis were excluded, leaving 244 diagnostic cases for analysis. Forty-six percent (112) of patients had diabetes mellitus, 14% (34) had an elevated baseline serum creatinine (> or =1.5 mg/dL), and an additional 7% (17) were dialysis dependent. Radiologists limited contrast volume by imaging only the symptomatic extremity when appropriate and using digital subtraction techniques as indicated. Our results showed that diagnostic contrast arteriography is associated with an acceptably low morbidity, has an accuracy that is unlikely to be surpassed by other modalities, and remains the diagnostic test of choice for lower extremity arterial disease.

Adult↗
PubMed2000

Chemical characterization and biological activity of Macfadyena unguis-cati (Bignoniaceae).

Macfadyena unguis-cati (L.) has been widely used in folk medicine as an anti-inflammatory, antimalarial and antivenereal. The purpose of this study was to chemically characterize the main plant components, and to evaluate the biological properties of some of the fractions derived from leaves (MACb) and liana (MACa) of this plant. Chemical characterization allowed the identification of the compounds corymboside, vicenin-2, quercitrin, chlorogenic acid, isochlorogenic acid, lupeol, beta-sitosterol, beta-sitosterylglucoside, allantoin and lapachol. The biological screening of fractions and/or purified substances derived from fractions revealed antitumoral and antitrypanosomal activities in fractions MACa/lapachol and MACb/MACb21, respectively. The anti-lipoxygenase and anti-cyclooxygenase effect seen in fractions MACa and MACb showed a partial correlation with the anti-inflammatory property attributed to this plant.

Animals↗
PubMed1997

Age-related differences in formal thought disorder in chronically hospitalized schizophrenic patients: a cross-sectional study across nine decades.

OBJECTIVE: This study used a cross-sectional design to examine the frequency of occurrence and severity of 10 different signs of thought disorder in schizophrenic patients across the lifespan. METHOD: Schizophrenic patients, who ranged in age from 19 to 96 years (N = 392), were examined with the Scale for Assessment of Thought, Language, and Communication. The cognitive functioning of the geriatric patients (patients over the age of 64, N = 120) was also assessed. RESULTS: Poverty of speech was more common and more severe in geriatric patients, while four different signs of thought disorder that reflect disconnected speech were less common and less severe in geriatric patients. Analysis of covariance found that the lower severity of disconnection thought disorders in the older patients was not attributable to differences in the amount of speech produced. CONCLUSIONS: Aspects of disconnected speech were less severe in older patients, while the severity and frequency of poverty of speech were greater. These findings suggest that the two previously identified separate dimensions of communication disorder in schizophrenia vary differently with age and possibly in their cognitive and biological underpinnings.

Adult↗
PubMed1997

Verbal fluency deficits in geriatric and nongeriatric chronic schizophrenic patients.

This study examined age-related differences and correlates of deficits on phonological and category fluency tasks performed by schizophrenic patients. Equal numbers (n = 41) of geriatric (age > 64) and nongeriatric chronically hospitalized schizophrenic patients were examined with tests of phonological and category fluency, verbal learning and delayed recall, confrontation naming, and reading, as well as overall estimates of cognitive impairment. Both types of fluency tests were performed very poorly by both groups. Age-related differences were found to be statistically significant. In both groups, category fluency impairments were correlated with deficits in naming, while phonological fluency deficits were best predicted by memory impairments. These data suggest that category fluency impairments are part of a general profile of impaired semantic functioning, whereas phonological fluency deficits may be induced by alterations in information processing capacity.

Aged↗
PubMed1996

Cognitive impairment and negative symptoms in geriatric chronic schizophrenic patients: a follow-up study.

Cognitive impairment is increasingly recognized as an important aspect of schizophrenia. Since cognitive impairment has many features in common with the negative symptoms of the illness, it is possible that some of the characteristics attributed to negative symptoms are due to an association with cognitive impairments. In order to test this hypothesis, 174 chronically hospitalized geriatric schizophrenic patients were examined twice at a 1-year follow-up with ratings of the severity of their symptoms (using the Positive and Negative Syndrome Scale: PANSS) and assessments of cognitive functions with the Mini-Mental State Examination and a brief neuropsychological battery aimed at the typical impairments seen in dementia. Positive symptoms were unassociated with any of the cognitive variables, while negative symptom severity was correlated with each of the cognitive measures. In the cross-temporal analyses, cognitive impairments were more stable over time than negative symptom scores, but cognitive impairment did not predict the severity of any negative symptom over time. At each assessment, however, cognitive impairment was strongly correlated with each of the seven negative symptoms studied. These data indicate that cognitive impairments and negative symptoms are related, but discriminable, features in schizophrenia and that the considerable overlap between some negative symptoms and estimates of cognitive function may suggest a rethinking of the definition of some of these symptoms.

Aged↗
PubMed1996

Age disorientation in chronically hospitalized patients with mood disorders.

Age disorientation was studied in 45 geriatric patients with chronic mood disorders. In a yearly assessment of cognitive functions, subjects were questioned about their age, year of birth, and the current year. Patients who misstated their age by > or = 5 years were considered age disoriented. Among the 45 patients, age-disorientation data were available for 32 patients, with the remainder either stating that they did not know their age or providing age-delusional responses. Six of the 32 patients were characterized as age disoriented at baseline and again at 12- to 18-month follow-up assessment. Age-disoriented patients performed worse overall on the Mini-Mental State Examination compared with patients who did not show age disorientation. Future studies of brain function and structure should include poor-outcome patients with mood disorders as well as patients with schizophrenia in attempts to identify the possible neurological dysfunctions that may underlie the phenomenon of age disorientation.

Adult↗
PubMed1996

How much does inferior capsular shift reduce shoulder volume?

The purpose of this study was to quantitate the effect of inferior capsular shift on shoulder volume. Four fresh frozen cadaveric shoulders were analyzed. Volume before and after shift was determined using 3 techniques: (1) Magnetic resonance imaging sequences were digitized to computer and analyzed for volume via a 35-mm camera using Cue 2 software. The capsule was delineated by contrast between light and dark regions. Volume was calculated by summing the total area of respective slices. (2) Ultrasound images, obtained after surgical exposure of the capsule, were digitized. Volume was calculated using the formula for a prolate ellipsoid. (3) An 18-gauge needle was used to inject and evacuate saline via an anterior approach. Quantity of aspirated fluid provided a direct measure of volume. Inferior capsular shift was performed. After the operation, measurements were repeated. Inferior capsular shift reduced volume in all shoulders with each technique. On average, inferior capsular shift reduced joint volume by 57 %). A measurable reduction in shoulder joint volume is an effect of capsular shift. This measurement may have clinical application if volume is an indicator of instability or laxity.

Cadaver↗
PubMed1995

Cognitive functioning in chronically hospitalized schizophrenic patients: age-related changes and age disorientation as a predictor of impairment.

Although schizophrenic patients manifest cognitive impairments, there is considerable variability across patients in the severity of this impairment. Very chronic patients with a poor outcome, particularly geriatric patients, manifest the most severe impairments, which have often been characterized as resembling dementia. This study examined age-related changes in cognitive functioning in a sample of schizophrenic patients (n = 393) ranging from 25 to 95 years of age, with a specific focus on identifying aspects of performance that were impaired in the youngest patients and preserved in the oldest patients. Age disorientation was examined in detail because it was previously found to predict global intellectual impairment in chronic patients. All 22 test items changed linearly over time (with age), with aspects of orientation, concentration, and delayed recall most impaired in young patients and naming and sentence repetition most preserved in the oldest patients. Age disoriented patients had more severe cognitive impairments at each age and the age-related changes in global impairment were more severe for these patients. The prevalence of age disorientation was consistent with previous reports and a one-year retest of the sample found that age disorientation was extremely stable over time within patients. The types of functions that are preserved in the oldest patients underscore previous findings of differences between geriatric schizophrenic patients and patients with degenerative diseases and the stability of age disorientation suggests that it is a trait of a subset of schizophrenic patients, those who appear to have the most severely declining course of illness.

Adult↗
PubMed1990

[Sjögren's syndrome in childhood. Description of a clinical case].

A case is reported of Sjögren's syndrome in childhood. According to Fox's classification, this patient presented all four inclusion criteria for the diagnosis of the disease. The Authors report the satisfactory evolution of the disease using therapy with FANS and corticosteroids and immunosuppressors during acute exacerbations.

Adrenal Cortex Hormones↗
PubMed1985

The trophotaenial placenta of a viviparous goodeid fish. III: Protein uptake by trophotaeniae, the embryonic component.

Protein uptake and degradation by trophotaenial cells of the viviparous goodeid fish Ameca splendens were studied colorimetrically and ultrastructurally using horseradish peroxidase (HRP) as a tracer and acid (ACPase) and alkaline (ALPase) phosphatase cytochemistry. Trophotaeniae are ribbon-like external projections of the embryonic gut that are equivalent to greatly hypertrophied intestinal villi. During gestation within the ovarian lumen, trophotaeniae are directly apposed to the internal ovarian epithelium (IOE) where they establish a placental association between the developing embryo and maternal organism. Trophotaenial absorptive cells possess an ALPase reactive brush border, an endocytotic apparatus, and ACPase reactive standing lysosomes. Ultrastructural studies of protein uptake indicate that cells of the trophotaenial epithelium take up HRP by micropinocytosis and degrade it within lysosomes. Initially (from 1.5-10 min), HRP is taken up in vitro at 22 degrees C at the apical cell surface and passes via endocytotic vesicles into an apical canalicular system. From 1.5 to 10 min exposure, HRP passes passes from the apical canalicular system to a series of small collecting vesicles. After 10 min, HRP is detected within large ACPase reactive supranuclear lysosomes. Three hours after an initial 1 h exposure to HRP, most peroxidase activity within supranuclear lysosomes is no longer detected. Presence of Golgi complexes, residual bodies, and secretory granules in the infranuclear cytoplasm suggest that products of protein uptake and hydrolysis are discharged across basal and lateral cell surfaces and into the trophotaenial circulation. Trophotaeniae of embryos incubated in vitro in HRP-saline take up HRP at an initial rate of 13.5 ng HRP/mg trophotaenial protein/min. The system becomes saturated after 3 h. Trophotaeniae incubated at 4 degrees C show little or no uptake. In trophotaeniae continuously pulsed with HRP for 1 h, then incubated in HRP-free saline, levels of absorbed peroxidase declined at a rate of 0.5 ng/mg trophotaenial protein/min. HRP does not appear to enter the embryo via extra-trophotaenial routes. These findings are consistent with the putative role of trophotaeniae as the embryonic component of the functional placenta of goodeid fishes. Trophotaenial uptake of maternal nutrients accounts for a massive (15,000%) increase in embryonic dry weight during gestation.

Animals↗
PubMed1985

The trophotaenial placenta of a viviparous goodeid fish. I. Ultrastructure of the internal ovarian epithelium, the maternal component.

Embryos of goodeid fishes develop to term within the ovarian lumen, where they undergo considerable increase in weight due to transfer of maternal nutrients across a trophotaenial placenta. The placenta consists of an embryonic component, the trophotaeniae, and a maternal component, the ovarian lining. The latter was examined by transmission electron microscopy, scanning electron microscopy, and light microscopy in both gravid and nongravid ovaries of the viviparous goodeid fish, Ameca splendens. The single median ovary of A. splendens is a hollow structure whose lumen is divided into lateral chambers by a highly folded longitudinal ovarian septum. Germinal tissue occurs within folds of the ovarian lining that extend into each of the two lateral chambers. Matrotrophic embryonic development takes place within ovarian chambers. During gestation, the lining of the ovarian lumen is in direct apposition to body surfaces and trophotaenial epithelia of developing embryos. The ovarian lining consists of a simple cuboidal epithelium, termed the internal ovarian epithelium (IOE), overlying a well-vascularized bed of connective tissue. Cells of the IOE are apically convex. Well-developed granular and agranular endoplasmic reticula and numerous large membrane-bound vesicles with electron-dense content occupy the apical cytoplasm of IOE cells. Two functional states of the same cell type are distinguished within the IOE. Phase I cells contain few, if any, large apically situated vesicles; Phase II cells contain many. Secretory products of the IOE are presumed to be an important source of nutrients for embryonic development. Structural and functional relationships of the IOE to the trophotaenial epithelium of developing embryos are discussed in relation to maternal-embryonic nutrient transfer processes.

Animals↗
PubMed1985

The trophotaenial placenta of a viviparous goodeid fish. II. Ultrastructure of trophotaeniae, the embryonic component.

Embryos of the viviparous goodeid fish Ameca spendens develop within the ovarian lumen, where they establish a placental association with the maternal organism and undergo a 15,000% increase in embryonic dry weight. The placenta consists of an embryonic component, the trophotaeniae, and a maternal component, the internal ovarian epithelium. Examination with light microscopy and with transmission and scanning electron microscopy reveals that trophotaeniae of A. splendens are extraembryonic membranes consisting of five ribbon-like processes originating from a tube-like mass of tissue that extends outward from the perianal region of developing embryos. There are two sets of lateral processes and a longer single median process. Trophotaeniae possess an outer epithelium that surrounds a highly vascularized core of loose connective tissue. Epithelial cells possess apical microvilli and a pronounced endocytotic apparatus. Cells of the trophotaenial epithelium are either tightly apposed along their lateral margins or separated by enlarged intercellular spaces. Regions of the trophotaenial epithelium possessing enlarged intercellular spaces are distributed in patches. The trophotaenial epithelium is continuous with the embryonic hindgut epithelium and is considered to be derived from it. Comparison of trophotaenial morphology in A. splendens with that reported in Xenotoca eiseni reveals differences in histological organization. The former possess unsheathed trophotaeniae, whereas the latter are sheathed. We postulate that the apposition of trophotaenial epithelium to the internal ovarian epithelium constitutes a placental association equivalent to a noninvasive, epithelioform of an inverted yolk sac placenta. Structural relationships of embryonic and maternal tissues of the trophotaenial placenta are discussed in relation to maternal-embryonic nutrient transfer processes.

Animals↗