Search PubMed⌕ Search

Biomedical subjects

J C Baron

Publications and source records attributed to J C Baron.

At least 181 records · Page 10Linked to original sources
PubMed1989

SPECT analysis of recent cerebral infarction.

We measured regional cerebral blood flow and [123I]iodoamphetamine (IMP) uptake in 16 patients with unilateral brain infarcts during the subacute period (Day 3 to Day 50) and again after 3 months. Our results show that the central and peripheral areas described earlier in the chronic period were already differentiated in the subacute period. The central area presented a short phase of luxury perfusion and a longer phase of IMP hyperfixation. The peripheral area showed both a slight regional cerebral blood flow decrease and an early IMP uptake decrease similar to those previously found in the chronic period. Contralateral regional cerebral blood flow during the subacute period, considered normal, was significantly lower than that during the chronic period.

Acetazolamide↗
PubMed1989

[Detection of a prostatic adenocarcinoma in the cysto-prostatectomy specimens of an invasive tumor of the bladder].

Among one hundred consecutive patients submitted to radical cysto-prostatectomy for invasive transitional cell carcinoma of the bladder, 26 also exhibited adenocarcinoma of the prostate on histological specimens: 17 microscopic foci and 9 larger prostate carcinomas. In 3 cases, the tumor was found in the apex of the prostate gland. Pelvic lymphadenectomy was positive in 4 cases but always corresponded to a urothelial metastasis. Follow-up was never marked by a metastatic development of this adenocarcinoma. This frequency of latent prostatic adenocarcinoma is not different from its observed incidence in the general population on autopsy studies. The high incidence of this association makes removal of the whole prostatic tissue during total cystectomy necessary.

Adenocarcinoma↗
PubMed1989

[Urologic manifestations of AIDS].

The frequency of urological manifestations of AIDS appears to be increasing at the present time: between 1985 and 1988, 38 HIV1 seropositive patients were examined in the Urology department. In seven cases, the positive serology was discovered during investigation of a urogenital infection and 21 patients suffered from declared AIDS. The reasons for admission to hospital were: urogenital infection: 14 cases, dominated by epididymitis (7) and prostatitis (5), characterized by their frequent progression towards abscess formation; tumours: 6 cases, including 5 Kaposi sarcomas of the penis; and, lastly, neurological manifestations, chronic renal failure and urological diseases unrelated to AIDS. This study indicates that serology should be performed routinely in cases with a known risk factor and/or with an atypical urogenital condition, particularly infectious. The adoption of aseptic techniques and rigorous protection of the entire surgical team is now absolutely necessary.

Abscess↗
PubMed1988

[18F]setoperone: a new high-affinity ligand for positron emission tomography study of the serotonin-2 receptors in baboon brain in vivo.

The potential usefulness of 18F-labelled setoperone, a high-affinity antagonist of the serotonin-2 (S2) receptors, to study the S2 receptors in vivo with positron emission tomography (PET) was investigated in four baboons. In the control state, there was a rapid wash-out of intravenously injected tracer from the cerebellum, a structure essentially devoid of S2, receptors, and marked retention in both the cerebral cortex and the striatum (region/cerebellum ratios up to 3 and 3.5 after 60 min in cortex and striatum, respectively). The retention of radioligand in the cerebral cortex was abolished after pretreatment with spiperone or ketanserin at saturating doses. In striatum, however, radioligand retention was fully prevented by spiperone but only partly by ketanserin. These results demonstrate that [18F]setoperone was bound to the S2 receptors in the cerebral cortex, whereas the radioligand was bound to both the S2 and the dopamine D2 receptors in the striatum. The high cortex/cerebellum ratio achieved indicates that [18F]setoperone should be a useful radiotracer for PET studies of the S2 receptors.

Animals↗
PubMed1988

Regional specific binding of [11C]RO 15 1788 to central type benzodiazepine receptors in human brain: quantitative evaluation by PET.

The central type benzodiazepine receptors were studied in 17 healthy human subjects with 11C-RO 15 1788 and positron emission tomography (PET). The brain regional distribution of the tracer in eight control studies performed after injection of trace doses of 11C-RO 15 1788 was consistent with that of benzodiazepine receptors. Saturation studies with co-injected cold RO 15 1788 in the remaining subjects showed a dose-dependent decrease of brain radiotracer until full inhibition of specific binding was achieved with doses above 0.1 mg/kg (four studies). Based on the results, a simple method to estimate the specifically bound 11C-RO 15 1788 regionally in a single PET study is proposed, using the data from the full-saturation studies as a stable estimate of the nondisplaceable radioligand concentration. Using this method, it was found that quasiequilibrium between the estimated specifically bound and nondisplaceable components was achieved at times equal to or longer than 20 min after tracer administration. The validity of this method was partly supported by further results, showing a good agreement between the regional specific binding so calculated and postmortem data of receptor density.

Adult↗
PubMed1988

Prostate-specific antigen in prostatic cancer.

In an attempt to establish the value of prostate-specific antigen (PSA) in prostatic cancer, serum PSA measurements were performed in 600 patients, including 75 previously untreated prostatic cancer patients. The mean PSA levels in the benign prostatic hypertrophy (BPH) and cancer groups were highly significantly different, but less difference was found between BPH and localized prostatic cancer. A PSA level above 50 ng/ml was never recorded for BPH, but lower levels can be due to either prostatic cancer or to BPH. Our data suggest that PSA is not a specific marker of prostatic cancer but increased serum PSA levels must draw the physician's attention to the possible presence of prostatic cancer.

Antigens, Neoplasm↗
PubMed1988

[Pure sensory stroke caused by thalamic hematoma].

A 59-year-old hypertensive patient presented with dysesthesias and a pure sensory deficit involving face, arm and leg on the left side of the body. CT scan and MRI showed a small hematoma in the posterior and lateral part of the right thalamus.

Hematoma↗
PubMed1987

Remote metabolic effects of cerebrovascular lesions: magnetic resonance and positron tomography imaging.

Combined Positron Emission Tomography (PET) and Proton Magnetic Resonance Imaging (MRI) study were performed in six patients with chronic supratentorial stroke to investigate whether remote hypometabolic regions revealed by PET showed any abnormality on MRI. Either regional oxygen consumption (n = 4) or glucose utilization (n = 2) were measured using PET and the 15O steady state 18FDG technique, respectively. Four patients, with deeply located brain lesions, showed a significant metabolic reduction in the overlying cerebral cortex. In the remaining two patients, affected by a large cortical infarct, there was a significant crossed cerebellar hypometabolism. The MRI weighted by the parameters spin density (rho), spin lattice (T1) and spin-spin (T2) relaxation times were obtained employing various sequences in the same subjects. In no patient did the MRI show any contrast modification in these hypometabolic remote regions, suggesting that subtle loss of tissue and/or biochemical change do not underlie the reduction in metabolic rate.

Adult↗
PubMed1987

Correction for intravascular activity in the oxygen-15 steady-state technique is independent of the regional hematocrit.

The oxygen-15 steady-state technique to measure the regional cerebral metabolic rate for oxygen requires a correction for the nonextracted intravascular molecular oxygen-15. To perform this correction, an additional procedure is carried out using RBCs labeled with 11CO or C15O. The previously reported correction method, however, required knowledge of the regional cerebral to large vessel hematocrit ratio. A closer examination of the underlying model eliminated this ratio. Both molecular oxygen and carbon monoxide are carried by RBCs and are therefore similarly affected by a change in hematocrit.

Brain↗
PubMed1987

Drug trials in migraine. The clinician's view on end points.

The definition of efficacy parameters in drug trials of migraine has received little attention and the tendency has been to take into account many parameters, which leads to the possibility of some positive results being obtained purely by chance. In trials of prophylactic drug treatment, the major parameter is the frequency of attacks. Patients with frequent interval headache should preferably be excluded from such trials since there is no satisfactory way to distinguish interval headache from mild migraine attacks. Severity and duration of attacks are important parameters but they are difficult to interpret since they are modified by symptomatic medication. The mean score of each attack by consumption of symptomatic medication gives a good estimate of the severity and duration of attacks, but the problem of equalizing different medications in order to obtain a single estimate has not been solved. In trials of abortive drug treatment, there is at present no agreement upon the single most important parameter. Severity of headache, severity of associated symptoms, global efficacy and duration of attacks are all modified by escape medication. The need for escape medication is a better parameter but its power to discriminate ineffective and partially effective drugs is low. It is suggested that the major parameter could be the number of attacks aborted in 2 h or less, which is a simple quantitative and clinically relevant criterion.

Clinical Trials as Topic↗
PubMed1987

In vivo assay for neuroleptic receptor binding in the striatum. Positron tomography in humans.

Using PET, we investigated the potency in six patients of therapeutic doses of neuroleptic drugs for preventing specific binding of trace doses of intravenously administered 76Br-labelled bromospiperone to corpus striatum in vivo. Measured receptor occupancy showed a clear-cut dose-dependent saturation curve with increasing daily oral dose of neuroleptics, indicating the validity and reliability of the method when used as an in vivo radioreceptor assay. Following drug withdrawal in eight patients, recovery to normal or supranormal receptor availability occurred in a matter of days. The results demonstrate an approach that may help resolve controversies about, and design better strategies for, neuroleptic treatment schedules.

Adult↗