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Biomedical subjects

D Gonzalez

Publications and source records attributed to D Gonzalez.

At least 73 records · Page 4Linked to original sources
PubMed1988

Comparative analysis of human and porcine neurocysticercosis by computed tomography.

Human and porcine cases of neurocysticerosis were compared by computed tomography in regard to the morphological characteristics of the parasites and the impact of the infection on the brain. In pigs and young people many parasites were usually found, but this was seldom the case in adult humans. These parasites were small and located mainly in the parenchyma and the subarachnoid space; no calcified cysticerci were found. In contrast, in adult humans cysticerci were heterogeneous in appearance and distribution. The brain of the pigs showed no evidence of inflammatory reaction while young people had oedema, enhancement and hydrocephalus; in contrast, adults showed diverse tomographic characteristics of brain response. Thus, the disease has at least 2 different forms. It may be mild with short development and parasites of similar appearance, as occurs in young hosts. In contrast, a long lasting disease occurs in adults, with diverse tomographic, neurological and parasitological features.

Adolescent↗
PubMed1987

Intravenous aminopropylidene bisphosphonate (APD) in the treatment of Paget's bone disease.

We studied the effect of the intravenous administration of the bisphosphonate APD in 9 patients with Paget's bone disease. The medication was given in a daily dose of 25 mg for 7 days in 0.9% saline infusion over 2 hours. At the end of treatment a significant fall of serum calcium and phosphate was observed. The urinary excretion of calcium decreased markedly and the serum levels of the mid-molecule PTH fragment increased from (mean +/- SE) 85 +/- 11 to 122 +/- 16 pg/ml (p less than 0.05). A marked and rapid decline in the hydroxyprolinuria was observed from 297 +/- 61 mg/24 h to 194 +/- 51 mg/24 h (p less than 0.01); meanwhile the serum alkaline phosphatase decreased from 102 +/- 22 to 84 +/- 21 KAU (p less than 0.05). The effect of ADP on suppression of hydroxyprolinuria varied markedly from +1 to -81% and was negatively related to the basal hydroxyprolinuria (r = -0.90; p less than 0.001). The duration of the bone turnover suppression was short. A relapse greater than 30% in hydroxyprolinuria was observed in 6 of 8 patients 2 to 3 months after APD withdrawal. The short-term intravenous administration of ADP is a useful means to rapidly suppress the activity of Paget's bone disease. However, further studies should determine the optimum dose, the length of treatment, and the need to associate oral therapy to induce a prolonged remission.

Aged↗
PubMed1987

Human neutrophils release serine proteases capable of activating prorenin.

Proteases from human neutrophils can generate angiotensin II directly from angiotensin I or angiotensinogen. We examined whether neutrophil protease also influences angiotensin formation by activating human prorenin (also called inactive renin). When incubated with partially purified plasma and amniotic prorenin, sonicates from 10(6) neutrophils resulted in 120 +/- 30% and 1,240 +/- 290% increase in renin activity, respectively. The pH optimum of neutrophil prorenin-activating enzyme(s) is 6.5-7.0, and the activity of the enzyme(s) is inhibited by a mixture of serine protease inhibitors but not by inhibitors of other proteases, suggesting that prorenin-activating enzyme(s) is a neutral serine protease(s). Stimulation of neutrophils by f-met-leu-phe in the presence of cytochalasin B resulted in release of prorenin-activating enzyme(s) in a dose-dependent fashion. We attempted to isolate prorenin-activating enzyme(s) from neutrophil granules using aprotinin-affinity and carboxymethyl cellulose chromatographies. Prorenin-activating enzyme(s) coeluted with cathepsin G and elastase activities. Prorenin activation was greatly inhibited by anticathepsin G antiserum. Purified cathepsin G activated prorenin in a dose-dependent fashion. Elastase probably also contributes to prorenin activation since purified elastase also activated human prorenin. We speculate that this neutrophilic angiotensin-generating system may play a role in the local generation and concentration of angiotensins by influencing multiple steps of the renin-angiotensin system.

Cathepsin G↗
PubMed1987

Characterization of purified rabbit uterine renin: influence of pregnancy on uterine inactive renin.

Using specific antibody raised against renal renin, we have documented that the majority of the uterine renin-like activity in gravid and nongravid uteri is immunoreactive renin. To characterize its physiochemical properties, we obtained highly purified uterine renin by two affinity chromatographic steps, pepstatin and antirenin. Uterine renin has a pH optimum of 6, an apparent mol wt of 38K, and a Km of 1.7 microM for homologous substrate. These properties are identical to those of renal renin and are not influenced by the pregnant state. In the basal state, an inactive form of the uterine enzyme constitute 55 +/- 10% of the total uterine renin. During pregnancy, active renin increased 40-fold as inactive renin fell to 4 +/- 3% of the total renin concentration. The renal renin concentration fell as plasma renin increased during pregnancy. These data suggest that the increased uterine renin concentrations during pregnancy are probably due to increased local production and conversion of renin precursor to the active enzyme. This stimulation of the uterine renin level appears to be independent of renal renin.

Animals↗
PubMed1986

Two possible mechanisms for precocious puberty induced in female rats by pituitary grafts.

Many reports indicate that prolactin has a role in puberty occurrence. The present study was developed to evaluate the action of pituitary grafts on puberty. Female rats grafted on day 21 with "adult' (90 days old) or "young' (21 days old) pituitaries showed precocious vaginal opening and first estrus. The puberty advancement induced by "adult' transplants was due to an increase in plasma prolactin values and can be blocked by bromocriptine treatment. The puberty advancement induced by "young' transplants was not associated with increased prolactin levels and cannot be blocked by bromocriptine. These results suggest the existence of two possible mechanisms in precocious puberty induced by pituitary grafts: a prolactin-dependent one and another one not directly related with prolactin.

Adrenal Glands↗
PubMed1986

Spontaneous fractures of uninvolved bones in patients with Paget's disease during unduly prolonged treatment with disodium etidronate (EHDP).

Three patients with Paget's disease of bone were treated by disodium etidronate (EHDP) without interruption during periods of 18 to 30 months. In one case the daily dose was also unduly high (approximately equal to 18 mg/kg/day). A moderate to conspicuous diminution of the renal function was observed in all cases. The three patients developed skeletal pain in a gradual but progressively severe pattern. Seven nontraumatic fractures in nonpagetic bones were encountered. EHDP produces blockage of bone mineralization and excessive suppression of bone remodeling, therefore increasing the risks of fracture. EHDP affects not only pagetic bones but normal skeleton. A baseline evaluation of the renal function might help to identify those patients with greater risk to develop skeletal side effects during EHDP treatment.

Aged↗
PubMed1985

Efficacy of the bisphosphonate APD in the control of Paget's bone disease.

Fifty-four patients with Paget's bone disease have been treated with the bisphosphonate APD. Twenty-six patients had not previously received treatment for Paget's disease; and 28 had been treated before with EHDP alone or in combination with calcitonin. APD was given orally in a mean dose of 500 mg daily (congruent to 6.8 mg/kg of body weight) for 4 to 12 months. Bone pain diminished or disappeared in 34 of 39 patients with symptoms. A very significant diminution of the biochemical indices of bone turnover was observed in all patients, but the responses were faster in patients who had not previously received treatment for Paget's disease. After 4 months of treatment the serum levels of alkaline phosphatase of previously untreated patients diminished from 58.8 +/- 8.0 to 20.0 +/- 3.9 KA units (P less than 0.001) and urinary excretion of hydroxyproline diminished from 108.6 +/- 16.9 to 42.4 +/- 8.3 mg/24 h (P less than 0.001). In 23 of 26 previously untreated patients the biochemical indices decreased to the normal range (complete response). A reduction of 50% or more without reaching the normal range was observed in the other 3 patients (partial response). Actuarial analysis of the duration of the effect 12 months after stopping APD disclosed that 63% of patients who had achieved a complete response but only 23% of those with a partial response were in biochemical remission. A second course of APD was administered to 11 patients. The results were as effective during the second as the first course in 9 patients, whereas 2 patients had no response to retreatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Late results of multiple fractions per day (MFD) with misonidazole in advanced cancer of the head and neck. A pilot study of the EORTC radiotherapy group.

In the EORTC Radiotherapy Group, the feasibility of multiple fractions per day (MFD) was tested in a pilot study from 1978 to 1980. Three daily fractions of 1.6 Gy were given (4 h interval) during 2 weeks (total dose 48 Gy), with a boost to about 70 Gy after 3-4 weeks. In 53 of the 179 patients, misonidazole was given on every irradiation day (1 g/m2, total 13-14 g/m2). Data on tolerance and early treatment results were published previously; results with a minimum follow-up period of 3 years are now available. Survival (actuarial is 21% and locoregional tumor control was obtained in 34% of patients; no significant differences were seen between the subregions in the head and neck area. Survival is better in patients treated with misonidazole (probably due to selection), but locoregional control was identical as in patients treated without the sensitizer. In February 1984, 38 patients were alive, 35 without evidence of local tumor (5 after rescue surgery). Metastases were seen in 16% and a second tumor in 7% of patients. Seventeen patients (9%) died of causes, possibly related to treatment; necrosis was observed in 8 (4 with local tumor). Late effects in the long survivors were comparable to what is usually seen after high-dose radiotherapy.

Follow-Up Studies↗
PubMed1982

Healing of osteitis fibrosa cystica after partial parathyroidectomy despite persistent parathyroid hyperfunction: a case report.

The diagnosis of primary hyperparathyroidism was made in a 55-year-old female with marked hypercalcemia (15 mg/100 ml) and hypercalciuria and skeletal x-rays showing typical lesions of subperiosteal resorption and numerous cystic areas. At surgery a left lower parathyroid adenoma presumably was totally excised. Serum calcium returned to normal levels immediately postoperatively, but 4 months after surgery hypercalcemia (11.5 mg/100 ml) was again found. During the following 18 months the patient was free of symptoms, and radiologic studies revealed complete healing of the subperiosteal resorption and repair of the bone cysts. Cortical bone mineral content also increased. However, elevated levels of serum parathyroid hormone (PTH) and calcium clearly indicated the persistence of primary hyperparathyroidism. Thus, a decrease in the degree of PTH hypersecretion permitted the repair of the skeletal lesions caused by a more severe level of parathyroid hyperfunction.

Bone Resorption↗
PubMed1982

The feasibility of high-dose multiple daily fractionation and its combination with anoxic cell sensitizers in the treatment of head and neck cancer. A pilot study of the Radiotherapy Group of the EORTC (European Organisation for Research on Treatment of Cancer).

From 1978 to the end of 1980, 179 patients with advanced head and neck tumors were accrued in a multicenter pilot study of the EORTC Radiotherapy Group, investigating the feasibility of high dose multiple daily fractionation (MDF) and its combination with misonidazole. The irradiation scheme consisted of three daily fractions of 1.6 Gy (four hour intervals) to a total dose of 48 Gy in two weeks, followed 3 to 4 weeks later by a boost to a total of about 70 Gy in 6 to 7 weeks. Misonidazole was given in daily doses of 1 g/m2 (total 13 or 14 g/m2) to 53 patients, thus sensitizing every radiation session. All patients had large head and neck tumors, with a poor prognosis. Acute reactions were well tolerated. Skin reactions were very moderate; mucosal reactions started at day 10 to 12. All patients had a confluent mucositis that lasted for one to two weeks. When the whole oral cavity was irradiated, reactions lasted somewhat longer. The boost caused no significant symptoms. The radiosensitizer did not modify the reaction pattern. Tumor regression was very impressive, so that palliation was obtained quickly. Nine patients died from treatment related causes. It is difficult to assess local control at this time, but at the time of analysis (August 1981), the actuarial control rate was 48% at 20 months, with misonidazole 57%. This difference, however, is not statistically significant. Survival of the total group is 31% at 20 months. In these patients with a heavy tumor burden the early results were considered a success by all participants. For patients with sufficient follow-up, late reactions can be evaluated. Some edema and fibrosis is seen, but did not exceed a degree which could be expected with single daily fractionation to the same dose. This study demonstrates the possibility of giving highly concentrated treatments to total doses equal to those used in conventional fractionation. For assessment of a possible benefit in local control and ultimate survival, a randomized study is necessary. Such a study is now underway in the EORTC Radiotherapy Group, comparing single daily radiotherapy with multiple daily fractionation with or without misonidazole.

Aged↗
PubMedDate not supplied

Hyperactivity in preweanling rats following postnatal alcohol exposure.

Neonatal alcohol exposure in rats has been used as a model to study the effects of third-trimester alcohol consumption in humans. In the present research, male and female rat pups were artificially reared (AR) and received condensed alcohol exposure (6 g/kg/day or 4 g/kg/day) on postnatal days (PNs) 4 through 9. Controls consisted of both artificially reared animals receiving maltose-dextrin substituted for alcohol and normally reared animals. These rats were tested for open-field activity at 18 days of age for four days. Both male and female rat pups that received the high dose of alcohol (6 g/kg/day) evidenced overactivity relative to pups in both control groups. These findings extend previous work and indicate that neonatal alcohol exposure can induce hyperactivity in young male rats.

Animals↗
PubMedDate not supplied

Locomotor activity and alcohol preference in alcohol-preferring and -nonpreferring rats following neonatal alcohol exposure.

Recently, we reported that the alcohol preferring (P) and nonpreferring (NP) rats, bred for differences in alcohol preference, showed different behavioral effects of neonatal alcohol exposure when tested as juveniles. Following neonatal alcohol exposure, the P line showed a greater increase in activity than the NP line relative to their respective controls. In the present study, P and NP rat pups were separated from their mothers and artificially reared from postnatal day (PND) 4 until PND 12. Pups were implanted with intragastric cannulas on PND 4 and fed a stock milk solution every 2 h via an indwelling cannula. One group had alcohol added to the milk diet during the 4 daytime feeds at a dose of 6 g/kg/day on PND 4-7 and a dose of 3 g/kg/day on PNDs 8 and 9. One control group was artificially reared and fed an isocaloric milk solution and a second control group was reared normally with a surrogate dam. Rats were tested as adults (80-day-old) for open-field activity and alcohol preference. Neonatal alcohol exposure caused equivalent increases in activity in P and NP rats. In the ethanol preference test, neither the P nor the NP rats showed any effect of neonatal alcohol treatment although there were large line difference in alcohol preference. These data suggest that the increased susceptibility of young P rats to neonatal alcohol exposure, measured by open-field activity, does not extend to adulthood. Furthermore, neonatal alcohol exposure does not appear to alter alcohol preference in either line.

Alcohol Drinking↗