Positron emission tomographic investigations of central muscarinic cholinergic receptors with three isomers of [76Br]BrQNP

We studied the potential of three radiobrominated isomers of BrQNP, (Z(-,-)-[⁷⁶Br]BrQNP,E(-,-)-[⁷⁶Br]BrQNP andE(-,+)-[⁷⁶Br]BrQNP), as suitable radioligands for imaging of central muscarinic cholinergic receptors in the human brain. These radioligands were stereospecifically prepared by electrophilic radiobromodestannylation of the respective tributylstannyl precursors using no-carrier-added [⁷⁶Br]BrNH₄ and peracetic acid. Preliminary pharmacological characterizations were determined by biodistribution, autoradiography, competition, displacement and metabolite studies in rats. The (-,-)-configuration presented important specific uptakes in brain muscarinic cholinergic receptor (mAChR)-rich structures and in heart, low metabolization rates and an apparent M₂ selectivity. The (-,+)-configuration revealed more rapid clearance, lower uptake, a higher metabolization rate and an apparent M₁ selectivity. Reversibility of the binding was confirmed for the three radiotracers. Positron emission tomography in the living baboon brain revealed high and rapid uptake in the brain and accumulation in the mAChR-rich structures studied. At 30 min p.i., theE(-,-)-radiotracer reached a plateau in cortex, pons and thalamus with concentrations of 29%, 24% and 19% ID/l, respectively.Z(-,-)-[⁷⁶Br]BrQNP also accumulated in these structures, reaching a maximal uptake (27% ID/l) in the cortex 2 h p.i. At 5 min p.i. a plateau (17% ID/l) was only observed in the cortex for theE(-,+)-[⁷⁶Br]BrQNP; by contrast, the other structures showed slow washout. After 3 weeks, the (-,-)-radiotracers were studied in the same baboon pretreated with dexetimide (1 mg/kg), a well-known muscarinic antagonist. In all the mAChR structures, the highly reduced uptake observed after this preloading step indicates that these radiotracers specifically bind to muscarinic receptors.Z(-,-)-[⁷⁶Br]BrQNP, which is displaced in higher amounts from M₂ mAChR-enriched structures, reveals an M₂ affinity. The two isomers having the (-,-)-configuration are potential probes for investigating central muscarinic receptors. The absolute configuration on the acetate chiral centre influences their muscarinic subtype selectivity and thecis-trans isomerism of the vinyl moiety affects their specific fixation.     

Eligible Veterans'' Choice Between VA-covered and Non-VA-covered Dental Care

Veterans who were eligible for dental care in Department of Veterans Affairs (VA) facilities at no monetary cost responded to a mailed questionnaire. Seventy-one percent were aware that they were actually eligible for VA dental care. However, only 48 percent reported the VA as their only or primary source of dental care. Eligibility status, perceived quality of VA dental care, use of VA medical care, perception that one's income meets expenses, and perceived need for dental care were significant correlates of using the VA as one's current source of dental care. Level of formal education, perception that one's income meets expenses, transportation pattern, geographic distance from a VA facility, and eligibility status were significant correlates of using the VA as one's current medical care source. Research on VA utilization offers the opportunity to study issues of access to, and use of, a large public health care system whose patients largely receive care at no monetary cost. Veterans' use of VA dental and medical care is apparently influenced by a wide variety of factors, ranging from barriers to access to non-VA systems, to characteristics of the VA delivery system itself, to need for treatment.     

Gadolinium ring enhancement and mass effect in acute disseminated encephalomyelitis

A 9-year-old boy presented with a subacute history of optic neuritis followed by brainstem involvement, with fever and a lymphocytic pleocytosis in the cerebrospinal fluid. Gadolinium-enhancing ring lesions were demonstrate in the white matter of the cerebrum, brainstem and cerebellum on day 17 of the illness, all appearing simultaneously as part of a monophasic illness. A parietal lesion exerted mass effect. Needling and biopsy yielded no evidence of a pyogenic lesion, tumour or tuberculosis and showed vasculitis. There was insufficient material for myelin staining. Dexamethasone therapy lead to rapid improvement of the radiological lesions: MRI and CT on day 34 of the illness showed complete clearing of the lesions except for residual abnormality at the biopsy site.     

Rhinophyma. The value of progressive dermabrasion]

After briefly summing up the nosology of rhinophyma, the authors report their experience with the surgical correction of this nasal disease, on the basis of eight cases. They explain their reasons for giving up dermasection and preferring dermabrasion.     

Conversions and complications in 185 laparoscopic adjustable silicone gastric banding cases

Background: Kuzmak's gastric silicone banding technique is the least invasive operation for morbid obesity. The purpose of this study was to analyze the complications of this approach. Methods: Between September 1992 and March 1996, 185 patients underwent laparoscopic gastroplasty by the adjustable silicone band technique. A minimally invasive procedure using five trocars was performed. Results: In 11 patients exposure of the hiatus was impeded because of hypertrophy of the left liver lobe which led to conversion in eight patients and abortion of the procedure in three other patients. Anatomical complications: We observed two gastric perforations and one band slippage at the early stage, one infection and three rotations of the access port. Functional complications: There were eight (4%) cases of irreversible total food intolerance resulting in pouch dilation and eight cases (4%) of esophagitis. One fatality on the 45th day in a patient with a Prader-Willi syndrome. Conclusion: The most disturbing complications of gastric banding technique are gastric perforation and pouch dilation. Their incidence may be reduced by improving the technique and by considering pitfalls of the procedure. Received: 28 May 1996/Accepted: 25 July 1996     

Acquired Loss of Red-Cell Wj Antigen in a Patient with Hodgkin''s Disease

A patient with Hodgkin's disease became temporarily Wj-negative with alloanti-Wj in his serum. Four human autoantibodies, and 1 of 2 murine monoclonal antibodies, with serological characteristics of anti-Wj were nonreactive with his red cells, confirming that they have anti-Wj specificity. Six siblings of the patient are all Wj-positive. The patient was also temporarily Anton-negative, and cross-testing between Wj and Anton red cells and antisera showed mutual compatibility, indicating that the antigens are the same. The patient and 3 of his 6 siblings are also of the rare Lu: - 13 phenotype, providing the first evidence that this is an inherited characteristic.