Biomedical subjects

G Herbster

Publications and source records attributed to G Herbster.

9 recordsLinked to original sources

PubMed1989

Ureteral replacement using ileum in compromised renal function.

Ureteral replacement by ileum is an accepted technique in a highly selective patient population. Two major contraindications in using an ileal ureter are compromised renal function (serum creatinine greater than 2) and a functionally abnormal bladder. We used ileum to bridge a ureteral defect in animals with half of a solitary kidney and low grade azotemia to see if the antirefluxing mechanism of the lower ureter prevented further deterioration in renal function. Twelve female mongrel dogs underwent a right nephrectomy, followed by a left partial nephrectomy six weeks later. Group I (six dogs) had a six cm. segment of ileum interposed between the upper and lower ureteral segments (nonrefluxing). Group II (five dogs) had a ten cm. segment of ileum placed from the upper third of the ureter to the bladder (refluxing). Cystograms, intravenous pyelograms, serum electrolytes, BUN and creatinine were obtained preoperatively, six weeks after the right nephrectomy, one month after left partial nephrectomy and six months after ileal replacement prior to sacrifice. The BUN and creatinine deteriorated in Group II compared to Group I, p = .02 and p = 0.4 respectively (Mann-Whitney test). The BUN and creatinine also deteriorated between one month after left partial nephrectomy and six months after ileal replacement within Group II, p = .07 and p = .14, respectively (Wilcoxon matched-pairs test) but not in Group I. These data suggest that the antirefluxing mechanism of the lower ureter might prevent further deterioration in renal function. We feel that ileum can be used with caution, as an interposition in compromised renal function.

Animals↗

PubMed1988

D1 and D2 dopamine receptor mechanisms in dopaminergic behaviors.

SKF 38393, a selective D1 dopamine receptor agonist, was investigated when administered alone and in combination with dopaminergic agonists in animal models of extrapyramidal behavior. SKF 38393 did not induce stereotypy in normal rats but enhanced apomorphine-induced stereotypy in a dose-dependent manner. SKF 38393 also augmented and altered the stereotypic response of dopaminergic agonists (+)-4-propylhydronaphthoxazine quinpirole, and ciladopa. The addition of SKF 38393 with ciladopa changed the behavioral response of ciladopa from a partial to a full agonist. SKF 38393 did not alter locomotor behavior; however, it augmented the stimulatory but not the inhibitory response of apomorphine on locomotion. In unilateral 6-hydroxydopamine-lesioned animals, SKF 38393 caused contralateral rotation that were similar to those of other dopaminergic agonists. The addition of SKF 38393 to both mixed D1/D2 (levodopa, pergolide) and selective D2 (PHNO, quinpirole) dopamine agonists resulted in a synergistic rather than an additive effect. No changes in behavior were observed in rats challenged with apomorphine after being treated 21 days with SKF 38393, PHNO, SKF 38393 plus PHNO, or saline. D1 agonism is capable of augmenting and altering dopaminergic behavior of both mixed D1/D2 and D2 dopamine receptor agonists. A combination of D1 and D2 dopamine agonists may represent optimal drug treatment for Parkinson's disease.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed1987

Adjuvant therapy of parkinsonian tremor.

The effect of long-acting propranolol hydrochloride (160 mg/d), primidone (250 mg at night), and clonazepam (4 mg/d) on the resting, postural, and kinetic component of tremor was investigated in ten parkinsonian patients in a double-blind crossover design. Tremor was assessed by patient opinion, clinical scoring, and accelerometer recordings. The amplitude and frequency of tremorgrams were determined by spectral analysis. Most patients preferred long-acting propranolol and chose to continue taking the drug. The mean clinical score for resting and postural tremor was significantly decreased by long-acting propranolol but not by primidone or clonazepam. Long-acting propranolol reduced the mean amplitude of resting tremor by 70% and the mean amplitude of postural tremor by 50%. Mean tremor amplitudes were not changed by primidone or clonazepam. Tremor frequency was unaltered by the drugs. No side effects occurred with long-acting propranolol but adverse reactions were common with primidone and clonazepam. Long-acting propranolol is a useful adjuvant therapy for the tremors associated with Parkinson's disease.

Aged↗

PubMed1987

PHNO, a novel dopamine agonist, in animal models of parkinsonism.

PHNO, a naphthoxazine compound, was investigated in animal models of central dopaminergic activity. The drug in doses of 5-300 micrograms/kg when administered subcutaneously, or transdermally, induced stereotypic behavior in rats which was blocked by haloperidol but not by reserpine pretreatment. In rats with unilateral 6-hydroxydopamine lesions of the substantia nigra PHNO induced dose-dependent contralateral turnings. The drug caused emesis in dogs and hypothermia in mice. PHNO bound to D-2 dopamine receptors in the rat striatum. Chronic injection with PHNO did not induce behavioral supersensitivity or increase dopamine receptor density. These data indicate that PHNO is a direct acting dopamine agonist that is highly potent. PHNO differs from other dopaminergic drugs and may be useful in the treatment of Parkinson's disease.

Animals↗

PubMed1987

Quinpirole hydrochloride, a potential anti-parkinsonism drug.

Quinpirole hydrochloride, a putative dopamine agonist, was investigated in animal models of central dopaminergic activity, to evaluate its possible role in the treatment of Parkinson's disease. The drug induced stereotyped sniffing in rats but, unlike apomorphine, did not produce a maximal behavioural response (stereotyped gnawing). Pretreatment with neuroleptics blocked the stereotypy induced by quinpirole. Quinpirole reversed the effects of reserpine and alpha-methyl-paratyrosine, caused dose-dependent contralateral rotations in rats with unilateral lesions of the substantia nigra induced by 6-hydroxydopamine and induced vomiting in dogs. Small doses of quinpirole decreased locomotor activity, an effect presumably mediated by pre-synaptic autoreceptors. Quinpirole bound to D2 dopamine receptors in the striatum of the rat. The chronic injection of both subthreshold and suprathreshold doses, failed to induce behavioral supersensitivity. These data indicate that quinpirole can stimulate central dopaminergic receptors, and that it is a partial agonist with direct-acting properties. Quinpirole differs from other dopaminergic drugs and may be useful for the therapy of Parkinson's disease.

Animals↗

PubMed1987

Caffeine and tremor.

Two percent of normal controls noted that drinking coffee made their hands shaky. Eight percent of essential tremor and 6% of Parkinson's disease patients thought that coffee worsened their tremor. In formal tests, a single oral dose of caffeine (325 mg) did not increase physiologic, essential tremor, or parkinsonian tremor at 1, 2, or 3 hours after ingestion. Caffeine only infrequently induces tremor in normal people, and it does not exacerbate pathologic tremor.

Caffeine↗

PubMed1987

Terguride, a mixed dopamine agonist-antagonist, in animal models of Parkinson's disease.

Terguride, an analogue of lisuride, decreased locomotor activity, produced cataplexy, and blocked apomorphine-induced stereotypic behavior. It did not induce stereotypies in rodents or emesis in dogs. However, in rats with unilateral 6-hydroxydopamine lesions of the substantia nigra, terguride produced contralateral rotation. Terguride bound to D-2 striatal dopamine receptors. Terguride has both agonist and antagonist actions at striatal dopamine receptors, but chronic administration did not produce behavioral supersensitivity. These pharmacologic properties differ from those of other antiparkinsonian agents; terguride may be effective for the chronic treatment of Parkinson's disease.

Amphetamine↗

PubMed1986

Clonidine in the treatment of essential tremor.

The effect of clonidine treatment (average dose 0.4 mg/day) was investigated in 10 patients with essential tremor in a double-blind placebo-controlled design. Tremor amplitude and frequency were recorded with an accelerometer. Tremor was not significantly altered by clonidine therapy. Side effects were common. It is concluded that clonidine is not effective treatment for essential tremor.

Clinical Trials as Topic↗

PubMed1985

Urinary undiversion using the existing ileal loop and distal right ureter.

Urinary undiversion is an accepted technique in a highly selective patient population. We reconstructed the urinary tract in six female mongrel dogs. A 15 cm. segment of ileum was isolated, both ends were closed and bowel continuity re-established. The proximal two-thirds of each ureter were anastomosed to the proximal end of the ileal segment. The distal one-third right ureteral segment, in continuity with the bladder, was anastomosed end-to-side to the distal ileal segment. Information from the intravenous pyelograms, renal function tests, electrolytes and pathological studies showed normal upper tracts without dilatation or obstruction, preservation of renal function and normal electrolytes except for mild hyperchloremia in all 6 animals. There was chronic pyelonephritis in one animal and mild focal renal inflammation in two animals. The uretero-ileal anastomoses were patent and the ureters were not dilated. The interposed ileum functions well as a conduit and does not become a reservoir over time. We believe incorporating ileum into the urinary tract in this technique of undiversion is a safe and effective clinical alternative in selected patients.

Animals↗