Preoperative imaging of abnormal parathyroid glands in patients with hyperparathyroid disease using combination Tc-99m-pertechnetate and Tc-99m-sestamibi radionuclide scans.

OBJECTIVE: To evaluate the efficacy of combined Tc-99m-pertechnetate and Tc-99m-sestamibi radionuclide scanning for imaging abnormal parathyroid glands in hyperparathyroid disease in a prospective study. SUMMARY BACKGROUND DATA: Established methods to localize abnormal parathyroid glands lack accuracy for routine use. Tc-99m-sestamibi used in conjunction with iodine-123 has excellent potential for preoperative imaging in patients with hyperparathyroid disease. An alternative method for parathyroid imaging was studied using Tc-99m-pertechnetate and Tc-99m-sestamibi. METHODS: Thirty patients with hyperparathyroid disease had Tc-99m-pertechnetate and Tc-99m-sestamibi subtraction radionuclide scanning to visualize abnormal parathyroid glands before surgery. The patients had surgery and pathologic confirmation of all parathyroid glands. RESULTS: In 23 patients with primary hyperparathyroidism, 12 of 13 solitary adenomas were visualized. Six of nine patients with diffuse hyperplasia had bilateral uptake consistent with diffuse hyperplasia. Three of nine patients had negative scans. One patient previously operated on for diffuse hyperplasia had only one gland scanned. Seven patients with renal failure-associated hyperparathyroid disease were scanned: five had bilateral uptake of Tc-99m-sestamibi consistent with hyperplasia, and two who had been previously operated on had localization of remaining abnormal parathyroid glands. CONCLUSIONS: Tc-99m-pertechnetate combined with Tc-99m-sestamibi subtraction radionuclide scanning is less cumbersome to implement than iodine-123 combined with Tc-99m-sestamibi scanning. It has a high sensitivity for imaging solitary parathyroid adenomas or persistent solitary hyperplastic glands. However it does not have the resolution necessary to delineate all parathyroid glands in diffuse hyperplasia.     

Kinaesthetic signals and muscle contraction.

Signals generated both peripherally and centrally contribute to the group of sensations termed kinaesthesia. Many experiments report sensations of position and movement under passive relaxed conditions without muscle contraction. However, kinaesthetic acuity is probably of greater functional value when subjects are active rather than passive and, accordingly, movement detection is markedly improved by muscular contraction. One mechanism contributing to this enhancement is likely to involve muscle spindle volleys. When identical microstimulation techniques are applied to skin, joint and muscle spindle endings innervating the hand, some cutaneous afferents and some joint afferents elicit a sensation, but activation of certain other cutaneous afferents and muscle spindle afferents rarely does. Activity in more than one muscle spindle afferent may be required for kinaesthetic sensations, whereas some single cutaneous and joint afferents may have a more 'secure' central projection.     

Seizure promotion and protection by D-1 and D-2 dopaminergic drugs in the mouse

Mice injected with pilocarpine (100-400 mg/kg plus 1 mg/kg methylscopolamine), picrotoxin (0.75-6 mg/kg) or strychnine (0.75-6 mg/kg) exhibited clonic or clonic/tonic convulsions. Pretreatment with the D-1 agonist CY 208-243 (0.375-1.5 mg/kg) dose-dependently potentiated the convulsions elicited by 100 mg/kg pilocarpine, but had neither a convulsant nor anticonvulsant effect in mice receiving picrotoxin (3 or 6 mg/kg) or strychnine (0.75 or 1.5 mg/kg). This facilitatory effect of CY 208-243 was abolished by the D-1 antagonist SCH 23390 (0.2 mg/kg). SCH 23390 by itself (0.05-0.8 mg/kg) dose-dependently protected mice against pilocarpine (400 mg/kg) seizures. Stimulating D-2 receptors with LY 171555 (0.167-4.5 mg/kg) dose-dependently protected mice against seizure activity induced by pilocarpine, but neither protected nor sensitised mice given picrotoxin or strychnine. The neuroleptics haloperidol (1-4 mg/kg), sulpiride (10-50 mg/kg), metoclopramide (1.25-6.25 mg/kg), thioridazine (0.5-2 mg/kg) and clozapine (0.5-2 mg/kg) had no effect on the seizure threshold to 100 mg/kg pilocarpine by themselves, although 10 mg/kg thioridazine and clozapine caused 100% convulsions, possibly through a toxic action. When administered in conjunction with a minimally effective quantity of CY 208-243 (0.375 mg/kg), however, all five neuroleptics interacted synergistically with the D-1 agonist to promote convulsions to pilocarpine (100 mg/kg). No such interaction occurred between submaximally protective doses of the D-1 blocker SCH 23390 (0.05 and 0.2 mg/kg) and a wide range of doses of the D-2 stimulant LY 171555 (0.167-4.5 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)     

New reference allelic ladders to improve allelic designation in a multiplex STR system

This paper reports the composition of a new reference allelic ladder mixture for use with a multiplex DNA profiling system consisting of six short tandem repeat loci. The loci included in this mixture are HUMTH01, D21S11, D18S51, D8S1179, HUMVWAF31/A, HUMFIBRA/FGA and an amelogenin sex test. Sequence analysis of individual ladder alleles was carried out and allelic designations made in accordance with the recommendations of the International Society of Forensic Haemogenetics (1992; 1994). A series of rare alleles which increase the range of alleles previously reported were identified. By including some of the rare alleles into the ladder marker system, we have significantly improved the ability to identify new alleles in unknown samples. Received: 12 August 1997 / Received in revised form: 7 November 1997     

Upper cervical ossicles in Down syndrome

Six patients with upper cervical spine ossicles and Down syndrome from a study population of 184 are described. The average age was 20.6 years at the time of diagnosis. Three of the patients were involved in tumbling. Radiographic anatomy of the ossicles and the dens, as well as serial radiographs in three of the six patients, suggest that this represents an avulsion of the upper end of the dens rather than an occipital vertebrae, ossiculum terminale, or os odontoideum, as previously described. The authors advocate restriction of high-risk activities for all patients with Down syndrome.     

Pheochromocytoma and paraganglioma: comparison of MR imaging with CT and I-131 MIBG scintigraphy

To ascertain the magnetic resonance (MR) imaging characteristics of pheochromocytomas and paragangliomas and to compare MR with computed tomography (CT) and iodine-131 metaiodobenzylguanidine (I-131 MIBG), 19 patients (18 with pheochromocytomas, one with a paraganglioma) were studied. The 18 patients with pheochromocytomas had had positive findings with I-131 MIBG scintigraphy. Abdominal pheochromocytomas were generally hypointense compared with normal liver on T1-weighted MR images and extremely hyperintense on T2-weighted MR images. MR imaging was preferable to CT in the evaluation of primary pheochromocytomas due to superior tissue characterization, particularly in the patient with hypertension and borderline catecholamine levels. For patients with recurrent or metastatic disease, the data suggest that I-131 MIBG scintigraphy is the examination of choice.