Search PubMed⌕ Search

Biomedical subjects

J Fuentes

Publications and source records attributed to J Fuentes.

At least 19 recordsLinked to original sources
PubMed1995

Chemotherapy and radiotherapy in locally advanced cervical cancer.

Radiotherapy has been standard therapy for locally advanced squamous cell cervical cancer. Neoadjuvant chemotherapy is being studied to improve responses and survival. We report a phase II study in locally advanced squamous cell cervical cancer (FIGO stages III and IVA) using chemotherapy with bleomycin, methotrexate and cisplatin (BMP) followed by radical radiotherapy. Of the 35 patients, 31 in stage III and 4 in stage IVA, 3 complete responses (CR) and 22 partial responses (PR) were achieved after chemotherapy treatment. Thirty-one patients completed radiotherapy; 19 achieved CR and 4 PR. Five-year actuarial survival for the entire group was 45% (95% confidence interval, 37-53%) with a median survival of 56 months. Patients with CR had a significantly better survival: the 5-year actuarial survival was 74% (95% CI, 59-89%). Recurrence developed in 4 of 19 patients. The most frequent side-effects were nausea and vomiting. Myelosuppression and impaired renal function also occurred. There was no evidence of radiotherapy toxicity enhancement. The stage and Karnofsky index were significant prognostic factors. It is concluded that BMP chemotherapy in advanced cervical cancer is effective and, followed by radiotherapy, allows a good control of this tumor. The group of patients with complete response have a low rate of recurrences and a long survival chance.

Adult↗
PubMed1995

Endometrial cancer stages I and II. Analysis of survival and prognostic factors.

BACKGROUND: Endometrial cancer is the most frequent gynaecologic neoplasia in women. Stages I and II account for 75% of endometrial cancers. METHODS: Diagnostic features, treatment and outcome based on therapy with surgery and/or irradiation of 185 endometrial cancer patients in Stage I and II were analysed retrospectively. RESULTS: There were 148 patients (80%) in Stage I and 37 (20%) in Stage II. Twenty-nine patients (16%) relapsed and 18 have died of cancer. The 5 and 10 year specific actuarial survival was 89% and 81% respectively. The 5 and 10 years disease free survival was 82% and 78% respectively. In our analysis of prognostic factors we observed a significantly worse survival for postmenopausal and Stage II patients, high grade tumors (grade III) and greater myometrial penetration (outer 2/3). CONCLUSIONS: Endometrial cancer has a relatively good prognosis partly because of its early diagnosis. There is general consensus that surgery is the optimal treatment in Stages I and II. While it is well documented that complementary irradiation improves survival in Stage II, there is no general agreement regarding the value of complementary irradiation in Stage I. Further studies are needed to delimit Stage I patients who would benefit from complementary irradiation.

Adult↗
PubMed1995

Synthesis and analgesic activity of 2-amino-5-tert-butyl-2-oxazoline.

2-Amino-5-tert-butyl-2-oxazoline (ATBO, 2) was synthetized from 3,3-dimethyl-2-iodobutyl isocyanate via N-(3,3-dimethyl-2-iodobutyl) urea (1). The structures of compounds 1 and 2 are based on analytical and spectroscopic data. Compound 2 induced in rats and mice a peripheral antinociceptive effect through both spinal and supraspinal mechanisms. ATBO did not impair motor coordination or activity of the experimental animals.

Acetates↗
PubMed1994

Direct transfer of rainbow trout to seawater induces several changes in kidney carbohydrate metabolism.

The levels of glycogen and glucose, and the activities of several key enzymes of glycogenolysis, glycolysis, gluconeogenesis and the pentose phosphate shunt were assessed in kidneys of rainbow trout (Oncorhynchus mykiss) of two sizes (80 and 140 g) after transfer to seawater (28 p.p.t.) during 7 days. The results indicated changes, mainly size-independent, in kidney carbohydrate metabolism during transfer of rainbow trout to seawater. An enhanced glycogenolysis and a concomitant increase in gluconeogenic enzyme activity were clearly observed in kidneys of both sizes of animals during transfer to seawater. Changes are suggested to be related to the known role of kidney as a glucose producer tissue thus satisfying, at least in part, the high energetic requirements of the osmoregulatory work performed by other tissues using glucose as fuel, such as the gills, during adaptation to seawater.

Adaptation, Physiological↗
PubMed1987

Modulation of pacemaker activity by IPSP and brief length perturbations in the crayfish stretch receptor.

We have studied the influences of brief stretches and releases and of inhibitory postsynaptic potentials (IPSPs) on pacemaker activity of the crayfish stretch receptor (RM1). Stimuli shift or reset the ongoing rhythm. Resettings were different if evaluated in interspike intervals containing perturbations, or in succeeding ones, and are referred to as early and late, respectively. Early resetting revealed that stretches and releases or IPSPs advance and delay, respectively, the next spike. With small stretches and releases or IPSPs, effects depend on the timing of the perturbation relative to the previous spike or phase, but above a characteristic mechanical perturbation amplitude the next spike fires at a fixed latency, invariant with the phase. Of particular interest was the finding that during late resetting the first successive intervals following stretches and releases or IPSPs were longer and shorter, respectively, than the period. This led, in approximately 50% of the cases, to a gradual recovery of the original pacemaker beat in the sense that spikes fire timed as if the early rhythm shift had not occurred. In conclusion, the recent firing history is essential in determining the RM1's response. The receptor's sensitivity is a complex nonlinear and periodic function of the pacemaker activity, and the response is due to interactions between pacemaker- and perturbation-induced transmembrane ionic currents. Although several alternative mechanisms may underly beat recovery, the results suggest that at least two coupled oscillators, one perturbable and the other not, provide a better explanation than a single oscillator. The physiological significance of resettings is unknown, but the early rhythm shift may synchronize RM1s in several segments when the animal's tail is moved, and conversely recovery would reduce synchrony, with obvious influences on shared postsynaptic neurons.

Animals↗
PubMed1985

Specimen collection time for enzyme analysis in urine.

Catalytic activity of N-acetyl-beta-D-glucosaminidase, alanine aminopeptidase, lactate dehydrogenase, isoenzyme 1 of lactate dehydrogenase, lysozyme, gamma-glutamyl transferase and alkaline phosphatase in urine specimens collected between 6 a.m. and 9 a.m. were determined in 25 patients with acute renal failure. We found no statistical differences (Wilcoxon's t test) between specimens collected at 6 a.m. and 9 a.m. We conclude that, in renal patients, the first morning specimen (overnight urine) may be used for enzyme analysis.

Acute Kidney Injury↗
PubMed1984

Coupled oscillators in an isolated pacemaker neuron?

The effects were examined of brief lengthening perturbations of different amplitudes on the pacemaker activity of the slowly adapting stretch receptor organ of crayfish. The analysis indicates that perturbation effects: (i) when elicited by low amplitudes, depend on the delivery time (or phase) of the perturbation relative to the last spike, while those evoked by larger amplitudes are phase-independent; (ii) tend to decrease, below the value of the natural interspike interval or pacemaker period, the interval at which the perturbation is delivered, anticipating the occurrence of the next spike; (iii) which follow the first poststimulus spike consist of phase-dependent lengthenings of interspike intervals which are greater for the first and decrease gradually in length in the following post-perturbation intervals; (iv) are gradually compensated because the pre-perturbation phase tends to be recovered in the interspike intervals following the perturbation and spikes gradually tend to occur closer to the instants when they would have fired without the perturbation. Although other models may explain the above behavior, phase compensation suggests strongly that at least two oscillators (i.e., an unperturbable oscillator and a stimulus sensitive one) underlie the pacemaker activity of the slowly adapting organ.

Adaptation, Physiological↗
PubMed1984

White noise analysis of pace-maker-response interactions and non-linearities in slowly adapting crayfish stretch receptor.

Input-output relations were investigated in the slowly adapting stretch receptor organ of crayfish using a Gaussian white noise length input with a 0.03-12.5 Hz band width and the resulting action potential output. The noise input was presented to the de-efferented receptor in situ, at three mean elongations and at four different amplitudes. The three mean elongations were set within the normal range in vivo, two at the extremes close to the minimum and maximum physiological lengths and the other in the mid-range. With white noise inputs there is a finite probability that the system will be tested in all possible conditions within the chosen band width because white noise has the advantage that it contains, with a finite probability, all possible stimulus wave forms at random. The analysis indicated similarities between the effects of the input variables, namely white noise amplitude and mean elongation. With low input variables the activity was periodic. With larger inputs, impulse rates were higher and irregular. The average length trajectories leading to a spike (i.e. the average stimulus) were either biphasic with high inputs or multiphasic and periodic with lower input variables. The frequency of periodicity increased with mean elongation. Although for a given length and noise amplitude a variety of individual length trajectories preceded spikes, the final biphasic shortening-lengthening average stimulus sequence before a spike was similar in all cases irrespective of the input variables. The number of possible trajectories decreased with increments in the input variables. The standard deviation of length values for each average stimulus was computed and displayed as a function of time relative to the spike. It was first constant, and decreased gradually to a minimum value at the spike reference. Standard deviation values were lower for higher white noise amplitudes and mean elongation. Simple, short-lasting stimulus wave forms in the white noise were isolated and the corresponding responses were computed. Responses were periodic at low input variables and aperiodic with larger inputs and also asymmetric, being larger and briefer for lengthenings than for shortenings. Asymmetries augmented with input increments. Investigation of the interactions between the pace-maker and the white noise effects showed that lengthenings were more effective when they occurred just after a spike while the effectiveness of shortenings was greater just before a spike.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗