Biomedical subjects
Publications and source records attributed to G Oliva.
Authors report a case of solitary fibrous tumour of the retroperitoneum that mimicked a renal mass. A review of the literature and a discussion on the biologic meaning of the lesion are presented.
OBJECTIVE: To characterize the testicular cytologic pictures in cryptorchild and contralateral testis related to seminal pattern. DESIGN: Controlled clinical study. SETTING: Andrological and urologic academic setting. PATIENTS: One hundred nine patients orchidopexied because of unilateral cryptorchidism compared with 35 normospermic subjects. INTERVENTIONS: Bilateral testicular fine-needle aspiration cytology. MAIN OUTCOME MEASURES: Seminal parameters; testicular cytologic features; plasma levels of FSH, LH, and T; and ultrasound testicular examination. RESULTS: The cytologic analysis revealed an important quantitative and qualitative impairment of spermatogenic line in all the excryptorchid testes. These alterations are present in the contralateral testes only when azoospermia or severe oligozoospermia were observed, whereas in moderate oligozoospermic subjects a normal tubular status was evident. A compensatory activity in normally descended testis of normozoospermic patients was present. CONCLUSIONS: In unilateral cryptorchidism, a frequent testicular damage in the orchidopexied and in the contralateral descended testis suggests that this condition is the end point of different pathological conditions, including testicular intrinsic (congenital) and extrinsic (anatomical) causes. Fine-needle aspiration cytology of both testes represents a tool in the assessment of the tubular status in excryptorchid subjects.
Specimens of tracheal mucosa were obtained from seven 2- to 5-year-old healthy fallow deer by an Olympus GIF P20 fibroscope. Biopsies were performed in two selected areas in the upper and lower third, respectively. Ultrastructurally, a total of 50,000 cilia were examined. Pathological cilia were found in all examined subjects. The prevalence of compound cilia showed a range of 0.9 to 3.0%. The presence of both intracytoplasmatic and swollen cilia ranged from 0.1 to 0.2%. Furthermore, the microtubular pattern was examined in 5,000 cross-sectioned cilia. Microtubular defects were seen to involve only the peripheral doublets and ranged from 1.3 to 4.1%. Finally, a central plug of electron-dense material was observed in 7-10% of the examined basal bodies.
BACKGROUND: Glucosamine 6-phosphate deaminase from Escherichia coli is an allosteric hexameric enzyme which catalyzes the reversible conversion of D-glucosamine 6-phosphate into D-fructose 6-phosphate and ammonium ion and is activated by N-acetyl-D-glucosamine 6-phosphate. Mechanistically, it belongs to the group of aldoseketose isomerases, but its reaction also accomplishes a simultaneous amination/deamination. The determination of the structure of this protein provides fundamental knowledge for understanding its mode of action and the nature of allosteric conformational changes that regulate its function. RESULTS: The crystal structure of glucosamine 6-phosphate deaminase with bound phosphate ions is presented at 2.1 A resolution together with the refined structures of the enzyme in complexes with its allosteric activator and with a competitive inhibitor. The protein fold can be described as a modified NAD-binding domain. CONCLUSIONS: From the similarities between the three presented structures, it is concluded that these represent the enzymatically active R state conformer. A mechanism for the deaminase reaction is proposed. It comprises steps to open the pyranose ring of the substrate and a sequence of general base-catalyzed reactions to bring about isomerization and deamination, with Asp72 playing a key role as a proton exchanger.
Thirteen dogs naturally infected with Leishmania infantum showing viscero-cutaneous signs of disease were treated with different dosages of liposomal amphotericin B (AmBisome). The animals were followed clinically and parasitologically over a period of eight months. Dogs which received three to five administrations of AmBisome 3-3.3 mg/kg showed rapid clinical improvement, with regression of lymphadenomegaly and splenomegaly, and cure of skin lesions. The clinical response was similar to that obtained with 14-21 doses of conventional antileishmanial drugs. However, follow-up lymph node aspirates remained positive for Leishmania in all dogs except one, which was treated with the total dose of AmBisome 15 mg/kg. The failure in parasitological cure may be due to inadequate drug targeting to parasitized cells, or to T-cell immune depression characteristic of patent cases of canine leishmaniasis, or to both.
This study was designed to characterize urinary bladder function in the aged rat (27 months of age). For comparative purposes, two different control groups were included into the experimental protocol: normal 6-month old and hyperdiuretic 6-month old rats. Increased threshold volume for micturition and increased bladder mass were found in both aged and hyperdiuretic rats. No difference in the amplitude of micturition contractions was detected between groups. In the aged rat, but not in the hyperdiuretic one, augmented threshold volume and bladder mass were associated with increased intravesical pressure at micturition and structural changes of intramural bladder innervation. When activated, the vesicovesical reflex did not show any change in terms of rate of isovolumetric contractions. In the aged rat, altered sensory information on the state of maximum fullness seems to play an important role in determining abnormal cystometric findings.
The present study was performed to evaluate the role of hand and facial contamination in the absorption of soluble nickel compounds in 41 male subjects employed in electroplating operations in 25 small factories in the province of Florence (Italy). Personal exposure to airborne nickel ranged from 0.10 to 42 micrograms/m3; the median (range) urine, hands and face nickel levels were 4.2 (0.7-50) micrograms/l, 39 (1.9-547) micrograms, 9.0 (1.0-86) micrograms, respectively. Face nickel values explained the bulk of the variance in urine nickel levels (42%). In stepwise multiple regression analysis all other variables were not significant. The log-linear model can be expressed as: log (urine-Ni) = 0.295 + 0.593 log (face-Ni). Our results suggest that skin contamination, especially facial skin, plays an important role in nickel absorption in exposed workers.
The three-dimensional structure of pentameric human serum amyloid P component at high resolution, the first reported for a pentraxin, reveals that the tertiary fold is remarkably similar to that of the legume lectins. Carboxylate and phosphate compounds bind directly to two calcium ions; interactions with a carboxyethylidene ring are mediated by Asn 59 and Gln 148 ligands of the calcium ions. These X-ray results indicate the probable modes of binding of the biologically important ligands, DNA and amyloid fibrils.
From January 1979 to December 1992, 74 patients with ureteral lesions due to ureteral or renal instrumentations, failed gynecological or reconstructive surgery were addressed to our department for a reconstructive program. Fifty-two of them were managed by standard ureteropyeloanastomosis or psoas bladder hitch and ureteral reimplants. Twenty-two patients (12 females, 10 males, age range 28-68 years) suffered from extensive ureteral lesions (5-7 cm) and were managed by major ureteral reconstructive surgery intended to restore urothelial continuity. Three patients had a solitary kidney, and 6 cases suffered from bilateral ureteral injuries. The procedures employed were: psoas kidney hitch with ureteropelvic anastomosis (4 cases), kidney psoas bladder hitch (5 cases), 'extended' psoas bladder hitch (5 cases), transureterouretero-anastomosis+psoas bladder hitch (5 cases), psoas kidney-bladder hitch and transureterouretero-anastomosis (1 case), renal autotransplantation (2 cases). Only 5 minor postoperative complications were observed and all patients but one had satisfactory results with a follow-up ranging from 6 to 84 months. The authors believe that the restoration of urothelial continuity is the best option compared to other technical solutions such as ileal replacement, or diversion and nephrectomy. Autotransplantation should be reserved for rare selected cases.
alpha-Prolamins are the major seed storage proteins of species of the grass tribe Andropogonea. They are unusually rich in glutamine, proline, alanine, and leucine residues and their sequences show a series of tandem repeats presumed to be the result of multiple intragenic duplication. Two new sequences of alpha-prolamin clones from Coix (pBCX25.12 and pBCX25.10) are compared with similar clones from maize and Sorghum in order to investigate evolutionary relationships between the repeat motifs and to propose a schematic model for their three-dimensional structure based on hydrophobic membrane-helix propensities and helical "wheels." A scheme is proposed for the most recent events in the evolution of the central part of the molecule (repeats 3 to 8) which involves two partial intragenic duplications and in which contemporary odd-numbered and even-numbered repeats arise from common ancestors, respectively. Each pair of repeats is proposed to form an antiparallel alpha-helical hairpin and that the helices of the molecule as a whole are arranged on a hexagonal net. The majority of helices show six faces of alternating hydrophobic and polar residues, which give rise to intersticial holes around each helix which alternate in chemical character. The model is consistent with proteins which contain different numbers of repeats, with oligomerization and with the dense packaging of alpha-prolamins within the protein body of the seed endosperm.
Regional changes in left ventricular size and function characterize left ventricular remodeling and start very early after myocardial infarction. We studied the diagnostic value of left ventricular dyssynergic patterns in predicting the presence of single versus multivessel disease (MVD). Fifty-three consecutive patients with acute myocardial infarction were studied by ECG, two-dimensional echocardiography, and angiography during the same hospitalization. Thirty-eight normal subjects served as the control group. According to the angiographic findings, the patients were categorized as having: single-vessel disease (SVD, n = 17), two-vessel disease (n = 17), and three-vessel disease (n = 19). Two-dimensional echocardiography was performed and optimal frames from five cardiac cycles were digitized and quantitatively analyzed off-line with a microcomputer. Echocardiographic wall-motion analysis demonstrated a depressed regional segmental thickening in the infarcted area that was characteristic for each echocardiographic view. In the segments remote from the infarcted area, however, the three patient groups displayed differences in function that ranged from hyperkinetic in patients with SVD to hypokinetic in patients with MVD. Patients with SVD constantly displayed a wider range of segmental thickening when compared with patients with MVD and the control group (p < 0.05). In conclusion, patients with SVD after myocardial infarction display compensatory hyperkinesis of remote segments, which is attenuated in patients with MVD. The present study introduces new parameters of segmental myocardial function that might be helpful in predicting SVD and MVD in patients after myocardial infarction.
Hexameric glucosamine-6-phosphate deaminase from Escherichia coli has been crystallized isomorphously with both phosphate and ammonium sulphate as precipitants, over a wide pH range (6.0 to 9.0). The crystals belong to space group R32 and the cell parameters in the hexagonal setting are a = b = 125.9 A and c = 223.2 A. A complete native data set was collected to 2.1 A resolution. Self-rotation function studies suggest that the hexamers sit on the 3-fold axis and have point group symmetry 32, with a non-crystallographic dyad relating two monomers linked by an interchain disulfide bridge. A possible packing for the unit cell is proposed.
Chlamydia trachomatis is the most prevalent sexually transmitted bacterial pathogen. Nevertheless, selective, rather than universal, screening for chlamydia has been recommended, largely because testing is expensive and requires considerable technical expertise. A total of 1,348 women in four family planning clinics in San Francisco, California, were screened from March 1987 to January 1988 to identify criteria for selective screening. Of these, 9.2% had a positive chlamydia test using direct fluorescence. Logistic regression analysis identified five factors associated with infection: age less than 25 years, cervical friability, single marital status, a new sexual partner within the past 3 months, and lack of barrier contraceptive use. No single risk factor or combination of risk factors had both a high sensitivity and a high positive predictive value for infection. While screening all women who were unmarried would detect 93% of those with chlamydia, the positive predictive value of 10.7% was not much higher than the overall prevalence. Conversely, screening all women with cervical friability, which had a positive predictive value of 23.2%, would only detect 11% of those with chlamydia. On the basis of the authors' findings, selective screening should not be used in high prevalence populations in which all women are at risk and should be screened for chlamydia.
The authors describe a rare case of inverted papilloma of the renal pelvis. A pathological, clinical and epidemiological review of this lesion is given. Up-to-date diagnostic work-up is outlined.
We report on the familial occurrence of congenital bulbar urethral stricture in 2 brothers. Embryological mechanisms are briefly discussed and the literature reviewed.
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