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Biomedical subjects

G Molina

Publications and source records attributed to G Molina.

At least 19 recordsLinked to original sources
PubMed1997

Changes in dopamine and acetylcholine release in the rat lateral hypothalamus during deprivation-induced drinking.

Neurochemical changes in the rat lateral hypothalamus during drinking were assessed in 20 min sampling intervals, using in vivo brain microdialysis. Water-deprived animals drank (11 +/- 1 ml) during the hour that water was available. Drinking was maximal (7.8 +/- 0.7 ml) during the first 20 min after water presentation and minimal during the last 20 min (0.5 +/- 0.4 ml). There was a local enhancement in DA turnover evidenced by an increase in the extracellular levels of dopamine (DA) (155 +/- 47% during the second sample after water presentation as compared to predrinking levels) and dihydroxyphenyl acetic acid (DOPAC) (132 +/- 9.7% in the sample that followed water removal). There was also an initial increase in the acetylcholine (ACh) release (145.1 +/- 21.7%) during the first 20 min after water presentation followed by a reduction (50.12 +/- 18%) 20 min later. These changes are congruous with previously published results suggesting that both neurochemical systems are involved in the regulation of water intake. Considering that the exogenous administration of cholinergic drugs in this hypothalamic area elicits drinking, the initial increase in ACh release could be interpreted as one of the neurochemical events driving this behavior. Since the local blockade of D2 receptors has been shown to result in drinking the progressive increase in DA turnover detected in this study, as well as the concomitant reduction in ACh release, could be involved in drinking attenuation.

Acetylcholine↗
PubMed1997

[Cryosurgery of liver neoplasms].

Cryosurgery is the in situ destruction of tissue using subzero temperatures. Its use for the treatment of some unresectable liver tumors has been clearly established as a therapeutic option. Experimental studies have demonstrated the feasibility of freezing of large liver volumes without any major metabolic and hemorrhagic complications. Modern cryosurgery has received substantial impetus from the development of automated cryosurgical apparatuses using liquid nitrogen. Intraoperative ultrasound has enhanced the process by enabling visualization of tissue freezing and ensuring precise and optimal treatment of the tumor. Clinical reports of cryosurgery for liver primary tumors and metastases have confirmed the safety of the procedure. Major complications include myoglobinuria, coagulopathy and pleural effusions. The benefit of cryosurgery is that it broadens the number of patients that can be brought to surgery and can potentially become disease-free.

Colorectal Neoplasms↗
PubMed1996

Hepatic cryosurgery precision: evaluation of ultrasonography, thermometry, and impedancemetry in a pig model.

One of the main problems of the use of liver cryosurgery is to be sure that a defined hepatic volume has been completely destroyed. We undertook an experimental pig study to determine histopathological evolution of cryolesions, to evaluate the value of intraoperative sonography, thermometry, and impedancemetry to monitor necrosis and to evaluate clinical and biological repercussions of hepatic cryosurgery. Forty-eight cryolesions were obtained by freezing each liver lobe of 12 experimental pigs during a 5-min contact with a flat cryoprobe cooled with liquid nitrogen. Cryolesions and the surrounding liver were monitored during cryosurgery by six thermocouple electrodes, five impedance electrodes, and intraoperative sonography. Animals were sacrificed immediately, 6 hr and between day 1 and day 32 after the procedure. Cryolesions were excised, and a full size pathological study was carried out. No morbidity or mortality was observed. At the end of the freezing time, cryolesions were hemispheric in shape, and their radius measured by sonography was 17.7 +/- 1.2 mm (mean +/- SD). Microscopic study showed sequential tissue alterations with edema, ischemic necrosis, tissue slough, and granulation. Cryolesions were sharply delineated from the normal liver tissue. The radius of necrosis at days 2 and 3 was 17 +/- 0.3 mm (mean +/- SD). It showed good correlation with the cryolesion size measured by intraoperative sonography. The temperature threshold to obtain complete normal liver necrosis was -15 degrees C. We found impedancemetry too difficult to use and not precise enough to monitor cryonecrosis. We conclude that intraoperative sonography and thermometry are useful means to monitor the extent of cryonecrosis during liver cryosurgery.

Animals↗
PubMed1996

[Transvaginal echographic evaluation of myometrial invasion in patients with endometrial cancer].

Twenty-one patients with endometrial cancer who underwent laparotomy, were pre-operatively examined by transvaginal sonography. A deep myometrial invasion (> 50%) was noted sonographically in 9 patients (42.3%), with a superficial invasion (< 50%) in 12 (57.2%). A deep invasion was histologically seen in 10 patients (47.6%), with a superficial invasion in 11 (52.4%). In myometrial deep invasion evaluation, transvaginal sonography showed a 90% sensibility, a 73% specificity, a 75% positive predictive value and a 93% negative predictive value. In 3 cases (14.3%) the invasion depth was sonographically overestimated and in 1 case (4.8%) underestimated. These results make possible an important role of transvaginal sonography in staging endometrial cancer, to select patients needing for pelvic and lomboaortic lymphadenectomy over total abdominal hysterectomy with vaginal collar.

Aged↗
PubMed1994

[Treatments of biliary fistulas following the removal of a Kehr tube after orthotopic liver transplantation].

Biliary tract complications are a major source of morbidity after liver transplantation. From October 1990 to September 1992, 77 patients, including 13 children and 64 adults, received 80 liver transplants. Biliary reconstruction was performed using a choledochocholedochostomy with a T-tube in 40 recipients. We report the management of bile leaks following T tube removal in 6 patients. In all cases, bile leak was diagnose by ultrasound examination requested for abdominal pain. In the first 2 patients, a surgical treatment was applied: Roux-en-Y choledochojejunostomy was performed on the first patient and simple suture of the fistula in the second patient. Two patients were managed nonoperatively using endoscopic and radiological procedures allowing placement of bile duct prosthesis and abdominal drainage. In 2 patients with small localized sub-hepatic collection, no surgical or radio-endoscopic treatment was attempted; spontaneous resolution of the collections was achieved in 2 months on ultrasound examination. All patients are alive, although, the patient who was operated on with a roux-en-Y choledochojejunostomy developed thrombosis of the right hepatic artery and biliary anastomotic stenosis which required further operations. We advocate endoscopic placement of endobiliary prosthesis and percutaneous biliary drainage as first-line therapy for significant fistula after T-tube removal. The use of choledochocholedochostomy without a T-tube when possible for biliary reconstruction in liver transplantation could be an effective procedure, but requires further evaluation.

Adult↗
PubMed1993

Mortality and cancer incidence among PVC-processing workers in Sweden.

The mortality pattern and the cancer incidence were investigated among 717 men who had been employed for at least 3 months during 1964-1974 in three Swedish PVC-processing plants. The mortality was followed 1964-1986 and the cancer incidence 1964-1984. Expected figures were calculated from Swedish national rates. Among Swedish citizens, the observed mortality and cancer incidence was close to the expected in most diagnoses. Among immigrants, mostly from Finland, there was a marked excess of circulatory deaths. This finding was probably due to the higher incidence of coronary mortality in Finland compared to Sweden. In the whole cohort, five cases of malignant melanoma had occurred as compared to 1.5 expected (SMR = 3.4, 95% confidence limit 1.1-7.9). This may be due to chance but merits further investigation since an increased incidence of malignant melanoma has previously been found among Norwegian PVC-manufacturing workers.

Chemical Industry↗
PubMed1991

Control of breathing in chronic obstructive pulmonary disease patients at rest and after beta-2 agonist inhalation.

Ventilatory function tests, ventilatory cycle analysis, mouth occlusion pressure (P0.1) and effective inspiratory impedance (P0.1/Vt/Ti) were measured in 11 healthy subjects and in 26 patients with chronic obstructive pulmonary disease (COPD). In COPD patients these measurements were repeated 20 min after inhalation of 400 micrograms of fenoterol. In patients we observed an increase of mean inspiratory flow (Vt/Ti), and a decrease of inspiratory time (Ti) and inspiratory duty cycle (Ti/Ttot). P0.1 and effective inspiratory impedance were significantly increased. Moreover, we found a direct correlation between forced expiratory volume in 1 s (FEV1) and ventilatory cycle components (Ti/Ttot, Ti) and an indirect correlation between FEV1 and Vt/Ti.P0.1 was directly correlated with Vt/Ti and indirectly correlated with ventilatory cycle components. These observations lead us to speculate on the possible role of two opposite mechanisms acting on the control of breathing of COPD patients. While the 'intensity' component of the ventilatory cycle would be set to maintain the tidal volume at a constant level, the 'timing' component would act in order to prevent inspiratory muscle fatigue. Furthermore, in patients responsive to beta 2-agonist drugs, fenoterol inhalation would act in synergy with the timing component of ventilatory cycle, lowering P0.1 and the effective inspiratory impedance.

Administration, Inhalation↗
PubMed1988

Adrenocorticotropic hormone and catecholamines in maternal, umbilical and neonatal plasma in relation to vaginal delivery.

The aim of this study was to evaluate the effect of vaginal delivery on both ACTH and catecholamines (DA, NE, E) secretion in the mother, the fetus (umbilical artery) and the newborn. Blood samples were obtained from 19 normal pregnant women and the corresponding umbilical cords, and from the newborns. Seventeen normal nonpregnant women, matched for age and parity, were also included in the study as "nonpregnant controls". The results demonstrate that in the mother, plasma catecholamines (CA) concentrations during labor and delivery are elevated above the values reported for normal nonpregnant women and there is a predominant E response. The concentrations of CA in umbilical arteries are very high compared to those in the corresponding mother and they fall rapidly after birth. Unlike that in the mother, the predominant CA response to parturition in the fetus and newborn infant is NE. The extraction rate of DA, NE and E from placenta is approximately 60%. The peripheral plasma levels of ACTH in pregnant women during labor are twice and 10 times as high as those observed in the corresponding umbilical arteries and in nonpregnant women respectively. At delivery they increase further. No significant differences are found between the values measured in the arterial cord blood and those in the venous cord blood and in the newborns. A way of explaining the prevalence of E and the higher ACTH/E ratio found in the mother in comparison with the fetus could be that in the mother the stress response to parturition is regulated mainly by the pituitary-adrenal axis, whereas in the fetus there is a prevalent stimulation of the sympathetic nervous system.

Adrenocorticotropic Hormone↗
PubMed1981

Mortality and cancer rates among workers in the Swedish PVC processing industry.

Personnel lists from four PVC-processing industries were collected on production of employees with at least three months of employment at the beginning of 1945 and the last day of employment December 31, 1974. Of 2073 persons, 103 could not be followed up, because they had moved abroad. The remaining persons comprise the cohort of 1970 individuals who were analyzed and compared with the national population with respect to mortality from various diseases and cancer morbidity. The death risk from myocardial infarction is elevated in the cohort. This elevation is most clearly apparent in the subcohort which had at least two years of exposure time and where the analysis was directed at circumstances chronologically close to the time of exposure. The myocardial infarction risk related to vinyl chloride exposure is discussed in relation to earlier studies on the vascular effects of vinyl chloride. An indication of an elevated risk of morbidity and mortality from tumors in the digestive organs is also present. However, this is not statistically confirmed. A few future follow-ups of the present study are necessary in order to clarify any possible elevated risk of tumors in the PVC-processing industry.

Adolescent↗