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Biomedical subjects

D Gomez

Publications and source records attributed to D Gomez.

At least 19 recordsLinked to original sources
PubMed2007

C-reactive protein as a predictor of prognosis following curative resection for colorectal liver metastases.

There is increasing evidence that systemic inflammatory response has a positive correlation with a poorer outcome in patients undergoing resection for solid tumours. The aim of this study was to analyse the impact of an elevated C-reactive protein (CRP), an outcome following curative resection for colorectal liver metastases. One hundred and seventy patients who underwent curative resection for colorectal liver metastases were included in the study. Laboratory measurements of haemoglobin, white cell, platelets, albumin and CRP were taken on the day before surgery. Elevated CRP (>10 mg l(-1)) was present in 54 (31.8%) patients. The median survival of patients with an elevated CRP was 19 months (95% CI 7.5-31.2 months) compared to 42.8 months (95% CI 33.2-52.5 months) for those with a normal CRP, P=0.004. Similarly, when assessing disease-free survival, patients with an elevated CRP had poorer disease-free survival (median of 11.8 months (95% CI 6.4-17.3) compared to median of 15.1 months (95% CI 11.1-19.1)), P=0.043. The result of the study showed that an elevated preoperative CRP is a predictor of poor outcome in patients undergoing curative resection for colorectal liver metastases.

Adult↗
PubMed2006

Mechanical properties of sarcomeres during cardiac myofibrillar relaxation: stretch-induced cross-bridge detachment contributes to early diastolic filling.

Sudden Ca2+ removal from isometrically contracting cardiac myofibrils induces a biphasic relaxation: first a slow, linear force decline during which sarcomeres remain isometric and then a rapid, exponential decay originating from sequential lengthening, i.e., successive mechanical relaxation, of individual sarcomeres (Stehle et al. 2002; Biophys J 83:2152-2162). Step-stretches were applied to the myofibrils, in order to study the mechanical properties of sarcomeres during this dynamic relaxation process. Stretch applied soon (approximately 10 ms) after Ca2+ removal accelerated the initiation of the rapid, exponential force decay and of the sequential sarcomere lengthening. After the stretch, a short, transient period (approximately 24 ms) remained, during which time force was enhanced and sarcomeres were homogenously elongated by the stretch. This period was similar to the duration of the switching-off of troponin C in myofibrils, as measured by stopped-flow. In contrast, when the stretch was applied during the rapid, exponential relaxation phase, force quickly decayed after stretch, back to the force level of isometric controls or even lower. Smaller stretches lengthened only those sarcomeres that were located at the wave front of the sequential sarcomere relaxation. The more the stretch-size was increased, the more of the contracting sarcomeres became lengthened by the stretch; those sarcomeres that were relaxed prior to stretch were barely elongated. These results indicate that the stretch accelerates myofibrillar relaxation by forcing the cross-bridges in contracting sarcomeres to detach. Subsequent rapid cross-bridge reattachment occurs during a short period after Ca2+ removal until troponin C is switched off. However, this switch off occurs approximately 5 times too fast to directly rate-limit the force relaxation under the isometric condition. After troponin C is switched off, stretching induces cross-bridge detachment without subsequent reattachment, and force rapidly decays below the isometric level. This may explain the rapid distention of the ventricular myocardium during early diastolic filling.

Animals↗
PubMed2004

Anatomical distribution of colorectal cancer over a 10 year period in a district general hospital: is there a true "rightward shift"?

INTRODUCTION: Recent studies of patients with colorectal cancer have suggested a shift towards the proximal colon and an increase in the incidence of right sided colon cancer. This study aimed to determine the anatomical distribution of colorectal cancer over a 10 year period in a district general hospital. METHODS: Records of patients diagnosed with primary colorectal cancer from 1993 to 2002 were reviewed for demographic data, histology subtype, and anatomical location of the tumour. Tumours located at and proximal to the splenic flexure were defined as right sided cancer and tumours arising distal to the splenic flexure were defined as left sided cancer. RESULTS: A total of 763 patients were included in the study, of whom all had adenocarcinoma and 99% were white. Sixty nine percent of cancers were left sided and 31% were right sided. Although there was a 4% increase in the proportion of right sided cancers, there was no statistically significant increase using logistic regression analysis. Mann-Whitney U test revealed no significant difference in age at diagnosis between the right and left sided cancers. Although a higher proportion of females were diagnosed with right sided cancer compared with left sided cancer, this was not statistically significant. CONCLUSION: The anatomical distribution of colorectal cancer has been fairly stable at this hospital with no evidence of a shift towards the proximal colon. No differences were identified in the tumour distribution with respect to gender and age at diagnosis. Our findings support the initial application of flexible sigmoidoscopy for investigating patients with suspected colorectal malignancy and follow up colonoscopy for selected patients to exclude right sided pathology.

Adenocarcinoma↗
PubMed2001

Rac1 mediates STAT3 activation by autocrine IL-6.

The activity of the small GTPase, Rac1, plays a role in various cellular processes including cytoskeletal rearrangement, gene transcription, and malignant transformation. In this report constitutively active Rac1 (Rac V12) is shown to stimulate the activation of STAT3, a member of the family of signal transducers and activators of transcription (STATs). The activity of Rac1 leads to STAT3 translocation to the nucleus coincident with STAT3-dependent gene expression. The expression of Vav (Delta1-187), a constitutively active guanine nucleotide exchange factor for the Rho GTPases, or activated forms of Ras or Rho family members, leads to STAT3-specific activation. The activation of STAT3 requires tyrosine phosphorylation at residue 705, but is not dependent on phosphorylation of Ser-727. Our studies indicate that Rac1 induces STAT3 activation through an indirect mechanism that involves the autocrine production and action of IL-6, a known mediator of STAT3 response. Rac V12 expression results in the induction of the IL-6 and IL-6 receptor genes and neutralizing antibodies directed against the IL-6 receptor block Rac1-induced STAT3 activation. Furthermore, inhibition of the nuclear factor-kappaB activation or disruption of IL-6-mediated signaling through the expression of IkappaBalpha S32AS36A and suppressor of cytokine signaling 3, respectively, blocks Rac1-induced STAT3 activation. These findings elucidate a mechanism dependent on the induction of an autocrine IL-6 activation loop through which Rac1 mediates STAT3 activation establishing a link between oncogenic GTPase activity and Janus kinase/STAT signaling.

Animals↗
PubMed2001

Optimization of cottontail rabbit papilloma virus challenge technique.

Disease induced by Cottontail Rabbit Papilloma Virus (CRPV) scarification in domestic rabbits shares many attributes with disease induced by human papilloma virus (HPV). CRPV induces squamous papillomas in domestic rabbits, of which approximately 70% transform into invasive carcinomas. In advanced tumors, virus is often undetectable, and occasionally, some rabbits undergo spontaneous regression of papillomas. Techniques utilized to scarify rabbit skin are diverse, often labor intensive and time consuming with the possibility for significant variability. Using four unique infection techniques, resultant papilloma incidence, time to onset, and total papilloma volumes were compared to determine an optimal challenge method. Five rabbits were each infected with CRPV via a tattoo gun with and without ink, an intradermal injection, manual use of a tattoo needle, or a sterile blade followed by manual use of a tattoo needle. Papilloma formation was monitored weekly after inoculation for 6 weeks. CRPV papillomas began as pinpoint foci at 3 weeks post challenge and grew exponentially throughout the course of measurement. Individual foci coalesced rapidly to form larger papilloma aggregates. Although intradermal injection was well tolerated and easily performed, it was the worst method of papilloma production (2.2 mm(3) at 6 weeks). The best method, a sterile blade followed by manual use of a tattoo needle, produced significantly larger papillomas over all time periods (>1100 mm(3) at 6 weeks, P<0.01). Inoculation of CRPV using this method produces highly repeatable papillomas beginning 3 weeks post-infection.

Animals↗
PubMed2000

Outcome of squamous cell carcinoma of the gingiva: a follow-up study of 83 cases.

BACKGROUND: Squamous cell carcinomas of the gingiva are relatively rare tumours. Standard treatment is based on surgery and radiotherapy. The extent of bone involvement affects mandibulectary indications. PURPOSE: A retrospective review of squamous cell carcinomas of the gingiva was performed to evaluate the incidence of mandibular or maxillary bone involvement. Indications for marginal and segmental bone resections are specified. MATERIAL: From 1985 to 1996, 83 patients with squamous cell carcinoma of the gingiva were treated at the Department of Surgery (Institut Bergonié, Bordeaux, France) and at the Department of Maxillofacial and Plastic Surgery (Centre Hospitalier Universitaire, Bordeaux, France). Forty-three underwent surgery plus postoperative radiotherapy. Twenty-two had flap reconstructions. Clinical evaluation and panorex roentgenography were the means used to evaluate bony invasion and to decide on the extent of bone resection. METHODS: A retrospective review of 83 consecutive patients was performed. This series is unusual in its homogeneity: surgery was performed by only two individuals and the radiotherapy was the responsibility of just two physicians. Outcome was calculated using the Kaplan-Meier method. RESULTS: Primary local control was achieved in 72 patients (87%). Overall survival and rate of recurrence were comparable to those of other squamous cell carcinomas of the oral cavity and oropharynx. CONCLUSION: Surgical resection continues to be the mainstay of treatment and this study tends to confirm the validity of modified neck dissection and marginal bone resection in suitably selected patients.

Adult↗
PubMed2000

Genomic variability of Haemophilus influenzae isolated from Mexican children determined by using enterobacterial repetitive intergenic consensus sequences and PCR.

Genomic fingerprints from 92 capsulated and noncapsulated strains of Haemophilus influenzae from Mexican children with different diseases and healthy carriers were generated by PCR using the enterobacterial repetitive intergenic consensus (ERIC) sequences. A cluster analysis by the unweighted pair-group method with arithmetic averages based on the overall similarity as estimated from the characteristics of the genomic fingerprints, was conducted to group the strains. A total of 69 fingerprint patterns were detected in the H. influenzae strains. Isolates from patients with different diseases were represented by a variety of patterns, which clustered into two major groups. Of the 37 strains isolated from cases of meningitis, 24 shared patterns and were clustered into five groups within a similarity level of 1.0. One fragment of 1.25 kb was common to all meningitis strains. H. influenzae strains from healthy carriers presented fingerprint patterns different from those found in strains from sick children. Isolates from healthy individuals were more variable and were distributed differently from those from patients. The results show that ERIC-PCR provides a powerful tool for the determination of the distinctive pathogenicity potentials of H. influenzae strains and encourage its use for molecular epidemiology investigations.

Carrier State↗
PubMed2000

Use of a low-prime circuit for bloodless heart transplantation in xenotransplant of 5-7 kilogram primates.

There is a great effort to decrease blood product use during open-heart surgery in pediatrics. We were presented with a research challenge to accomplish heart xenotransplantation from donor cynomologous monkey (Macaca fascicularis) to recipient olive baboon (Papio anubis) of 5-7 kilograms without benefit of donor or banked blood products. The purpose of this study was to design and implement a practical, low-volume circuit to minimize hemodilution and avoid the use of blood products. A simple circuit was assembled using a low-volume oxygenator with hardshell venous reservoir, an 1/8-inch arterial line, an 1/4-inch venous line, and gravity drainage. Three xenotransplants were performed and evaluated. The mean recipient weights were 6.3 +/- 0.7 kg. Circuit prime volume was 228 +/- 5.8 mL, and bypass time was 85 +/- 6.7 min. Blood flow rates were 585 +/- 113 mL/min with postmembrane arterial line pressures of 344 +/- 81 mmHg, and patient mean arterial pressures (MAP) of 51.4 +/- 16.7 mmHg. Venous saturations were 63.7 +/- 8.0%. The hematocrit prebypass was 37.4 +/- 3.2, bypass 20.7 +/- 0.9, post-MUF 27.8 +/- 3.3, and 7 days postoperative 24.5 +/- 7.5%. Platelet count was 289 +/- 1.1 K/microL, 147 +/- 37.1 K/microL, and 322 +/- 292.7 K/microL prebypass, postbypass, and 7 days postoperative, respectively. Plasma-free hemoglobin prebypass was 7.5 +/- 4.4 mg/dL and postbypass 22.2 +/- 16.5 mg/dL with no noted hematuria during and after the procedure. All patients survived and were successfully weaned from cardiopulmonary bypass (CPB) with same day extubation. A low-prime circuit for bloodless heart surgery is possible. To achieve low reservoir levels, especially without the use of an arterial line filter (ALF), it is necessary to have a full armament of monitoring and alarm devices.

Animals↗
PubMed1998

[Gunshot injuries of the face. Analysis of 165 cases and reevaluation of the primary treatment].

Our large experience of shotgun injuries to the face emphasizes the need for a reappraisal of primary treatment for this poorly documented topic. The medical records of 165 patients, treated at our institution between january 1st, 1982 and december, 31st 1996 for such an injury, were reviewed. Almost all cases were exclusively self-inflicted lesions. The guns were mainly twelve-gauge and occasionally 16 or 20-gauge. Close range wounds in an heterogeneous area--soft-tissue, mandible, muscles of the tongue and floor of the mouth, oral and nasal cavities, maxilla and paranasal sinuses--caused massive damage. A topographic classification based on the soft-tissue and bone loss is reported. After initial management (including securing the airway and control of bleeding), conservative debridement of all devitalized tissues and stabilization of the fractures were performed. As soon as possible, bone and soft tissue reconstruction was undertaken using local or distant flaps. However, immediate definitive reconstructive procedures were scarcely [corrected] used and only in particular cases. We believe that a carefully planned reconstruction schedule is required to achieve satisfactory appearance and function.

Facial Injuries↗
PubMed1997

The integration of nitrogen and carbon catabolite repression in Aspergillus nidulans requires the GATA factor AreA and an additional positive-acting element, ADA.

The expression of the structural genes of the proline utilization cluster of Aspergillus nidulans is repressed efficiently only when both repressing carbon and nitrogen sources are present. Two hypotheses can account for this fact. One is a direct or indirect competition mechanism between the positive-acting AreA GATA factor, mediating nitrogen metabolite repression, and the negative-acting CreA protein, mediating carbon catabolite repression. The second is to propose that CreA prevents the binding or activity of another, as yet unidentified, positive-acting factor, here called ADA. We show the second possibility to be the correct one, and we localize the new positive cis-acting element within 290 bp of the prnD-prnB divergent promoter.

Aspergillus nidulans↗
PubMed1997

Study of the course of the incidence angle during growth.

Standing posture is made possible by hip extension and lumbar lordosis. Lumbar lordosis is correlated with pelvic parameters, such as the declivity angle of the upper surface of the sacrum and the incidence angle, which determine the sagittal morphotype. Incidence angle, which is different for each individual, is known to be very important for up-right posture, but its course during life has not yet been established. Incidence angle was measured on radiographs of 30 fetuses, 30 children and 30 adults, and results were analysed using the correlation coefficient r and Student's t test. A statistically significant correlation between age and incidence angle was observed. Incidence angle considerably increases during the first months, continues to increase during early years, and stabilizes around the age of 10 years. Incidence is a mark of bipedism, and its role in sagittal balance is essential.

Adult↗
PubMed1997

Computerized hand diagnostic/rehabilitation system using a force feedback glove.

This paper describes recent results of a unified computerized system for hand diagnosis and rehabilitation. Automatic diagnosis data collection and Virtual Reality rehabilitation exercises are the main characteristics of the system. The diagnosis subsystem includes a tactile sensing glove in addition to standard devices such as electronic dynamometer, pinchmeter and goniometer. Three standard rehabilitation exercises were simulated in a Virtual Reality environment, using the WorldToolKit graphics library. The first two exercises (ball squeezing and DigiKey) allow measurement of finger forces exerted during the rehabilitation routine. The third exercise (Peg board) involves the patient's visual-motor coordination. The rehabilitation subsystem uses a VPL DataGlove retrofitted with Rutgers Master (RM-I) and its interface. The exercises involve manipulation of objects with different stiffnesses and geometry. Grasping forces were modeled and fed back using the Rutgers Master worn on patient's hand. Data is gathered in real time from both diagnosis and rehabilitation subsystems. Finger specific forces recorded during rehabilitation exercises allow better diagnosis of the patient impairment. An ORACLE database is used to store and manipulate patients' records. Proof of concept trials were performed in a clinical environment. Some results of patient records analysis are presented in this paper. A new version of the system using an RM II haptic interface is presently under consideration.

Adult↗
PubMed1994

Dynamic force feedback in a virtual knee palpation.

A virtual model of a knee joint with muscles, ligaments and bones has been developed. This model includes realistic 3-D surface deformation and tissue stiffnesses. Tissue and bone deformation (palpation) produces real time force feedback to the user hand wearing a DataGlove and Rutgers Master. Collision detection algorithms determine when and where the virtual hand palpates the surface model. This user interaction with the muscles and bones of a human knee model may be used as a training and planning tool for knee surgery.

Algorithms↗
PubMed1992

Intervention program for obese school children.

The purpose of this study was to implement and evaluate a program for obese school children. A pretest-posttest design was utilized. Data was collected related to weight status, skinfold measurements, self-esteem, and nutritional knowledge. A convenience sample of 26 children, in the fourth to sixth grades, completed this 9-week program. The results indicate that self-esteem increased significantly (p less than .001) between the pretest and posttest interval. Weight status and nutritional knowledge showed no improvement. Exercise was difficult to assess on self-report, therefore no conclusions were were drawn in relation to this variable. Future research will be directed toward refining this intervention program.

Child↗
PubMed1992

[A comparative study of the cost of open-circuit as opposed to closed-circuit ventilation].

The authors compared two open randomized groups of patients undergoing surgery through general anaesthesia. Group 1 consisted of 54 patients ventilated by a Siemens 900 B ventilator in open circuit, and group 2, 56 patients ventilated by an ELSA de Gambro ventilator in a closed circuit. Comparative hour cost for nitrous oxide (N2O), oxygen (O2) and halogen gas, Enflurane, Isoflurane, was noted. All patients received the same regimen of anaesthesia and the two groups were identical in age, weight, surgery, respiratory volume and ventilation time. The evaluation of comparative hour cost included specific materials of close circuit ventilator: CO2 filter (Aridus), Lime. Were excluded maintenance and gas consumption expenditures before patient connected to the ventilator. The total hour cost (O2, N2O, specific materials for close circuit, without halogen gas) was 8.23 FF in closed circuit against 13.28 FF in open circuit, an economy of 38.27%. Hence, for oxygen, the hour cost was 0.70 FF in open circuit against 0.27 FF in closed circuit (gain of 65.3%). For nitrous oxide, the hour cost in open circuit was 12.50 FF against 2.44 FF in closed circuit (80.5%). For Isoflurane, the open circuit hour cost was 41.38 FF against 22.44 FF in closed circuit (47%). For Enflurane, the open circuit hour cost was 14.17 FF against 5.94 FF in closed circuit (58.1%). And, lastly for Enflurane, open circuit hour cost was 14.17 FF against 5.94 FF in close circuit, gain of 58.1%. These "modest" economy against those found in previous studies can be explained by the long-time duration of ventilation, saturating time in open circuit more or less long, depending on the physician, specific materials for closed circuit ventilation--lime, CO2 filter--in not taken into account, the hour cost of O2 + NO2 goes from 8.23 FF to 2.71 FF, and the gain against the close circuit becomes 79.6%: reducing hour cost by 5 times. In order to improve the effective cost of close circuit, the authors proposed: the use of closed circuit ventilation for more than 3 hours surgery, gas saturation in closed circuit after denitrogenation--which demands the use of halogen infjectors, and lime in containers cheaper than disposable cartridges. Respecting the above criteria, the total hour cost in close circuit fell to 4.90 FF, gain of 63% against open circuit. For O2 et N2O, the hour cost goes from 1.34 FF in close circuit to 13.28 FF in open circuit, 90% economy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Production of corneal lesions using high-intensity focused ultrasound.

In order to study the potential use of ultrasound as a noninvasive system for altering corneal curvature, we used high-density focused ultrasound at a frequency of 4.8 MHz and 7.9 MHz to produce corneal lesions in the rabbit eye. Intensity and duration threshold exposure conditions were determined for the production of minimally visible lesions. Threshold lesions were initially apparent as discrete white opacities resulting from stromal edema and disruption. Light and scanning electron microscopy of higher-energy, suprathreshold lesions revealed more extensive disruption, including the formation of a superficial stromal depression and a larger zone of edema and disorganization surrounding each lesion. Posterior stromal lamellae, endothelium, and Descemet's membrane were intact. Healing and reepithelialization resulted in a smooth corneal surface with no residual opacification. Threshold determinations predict safe exposure levels to the cornea during insonification of other ocular structures. Selective heating of the peripheral cornea using focused ultrasound may be a useful technique for correcting astigmatism.

Animals↗