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Biomedical subjects

K Miller

Publications and source records attributed to K Miller.

At least 343 records · Page 19Linked to original sources
PubMed1994

Endoscopic Nd:YAG Laser Coagulation of Intramural Endometriosis of the Bladder

Treatment of intramural endometriosis of the bladder using the Nd:YAG laser is described. An operative cystoscope fitted with a 600 µ fibre is introduced into the bladder. At a power setting of 50 W, superficial coagulation of the visible lesion is performed. The coagulation technique corresponds to that used for the treatment of superficial bladder carcinomas. Three patients were managed in this way. In all patients dysuria and hematuria either significantly decreased or disappeared altogether. No intraoperative complications were observed. This new technique appears to be superior to surgical excision techniques, especially in cases where the lesion is situated on the roof of the bladder. Further studies need to be conducted to compare results obtained from this technique with those of the CO2 laser or excision technique.

Journal Article↗
PubMed1994

NMDA receptor blockade and spinal cord ischemia due to aortic crossclamping in the rat model.

Recent brain research proposes that, during ischemia, synaptically released excitatory amino acid neurotransmitters accumulate at toxic concentrations with ensuing neuronal death. Their action is mediated by the receptor subtype N-methyl-D-aspartate (NMDA). The protective effect of NMDA receptor blockade with intrathecal MgSO4 and MK-801 was investigated during spinal cord ischemia induced by aortic occlusion of 12 minutes. Male Sprague-Dawley rats, 250-300g, underwent intrathecal administration of 20 microL of normal saline (SA n = 16), MgSO4 1M (MG n = 16), or MK-801, 25 mM solutions (MK n = 16) in a randomized order. After 2 hours, the animals underwent occlusion of the thoracic aorta and subclavian arteries for 12 min. An additional control group (CO n = 16) underwent occlusion for 12 minutes, without intrathecal injection. The animals were scored according to their functional performance (LS = lesion score) each day for four days by a blinded observer. Mean LS were calculated for each group at a given day. Treatment and control groups were not different at day 1 (P = 0.302). Group MG was improved from groups SA (P = < 0.0039) and CO (P = < 0.0048) at day 4. This study demonstrates that although intrathecal NMDA receptor blockade with MgSO4 or MK-801 does not prevent paraplegia due to spinal cord ischemia in the rat, it could however influence the rate of recovery after ischemic injury.

Animals↗
PubMed1994

Levels of dissociation and histories of reported abuse among women outpatients.

A total of 99 female patients consecutively admitted to an adult psychiatric outpatient clinic were surveyed about their history of physical and sexual abuse. Sixty-five percent of this sample reported having been physically abused, sexually abused, or both during their lifetimes. Scores on the Dissociative Experiences Scale were significantly higher among those reporting a history of sexual abuse than among those reporting a history of physical abuse or no history of abuse, who did not differ from each other. Dissociative Experiences Scale scores were important predictors of histories of sexual abuse among this sample. The implications of these findings for outpatient evaluation are discussed.

Adolescent↗
PubMed1994

Short report: a comparative study of the interaction between antacid and H2-receptor antagonists.

The influence of concomitant antacid administration on the relative bioavailability of the H2-receptor antagonists cimetidine, famotidine, nizatidine and ranitidine, was investigated in a panel of 21 healthy, adult male volunteers in an eight-way crossover trial. Administration with antacid reduced the bioavailability of all agents tested. The reduction in area under the serum concentration-time curve (AUC) was greatest for cimetidine (23%) and ranitidine (26%) and least for nizatidine (12%) and famotidine (19%). Reductions in peak serum concentration (Cmax) followed a similar pattern. The times of peak serum concentrations were not affected by antacid. Comparison of the relative bioavailability among all drugs tested showed no statistically significant differences in the effect of antacid administration on these agents. However, a high degree of intersubject variability was observed.

Adult↗
PubMed1994

Prostaglandin E1 versus linsidomine chlorhydrate in erectile dysfunction.

Recent experimental work has demonstrated that nitric oxide (NO) is the neurotransmitter responsible for cavernous smooth muscle relaxation. Different studies on the performance of the direct NO donor linsidomine chlorhydrate (SIN-1) in patients with erectile dysfunction have had conflicting results. We performed a single-blind cross-over trial in 20 patients with erectile dysfunction of mixed etiology comparing prostaglandin E1 (PGE1) to SIN-1 at two different dosages (1 and 2 mg, respectively) in order to determine the effectiveness of SIN-1. PGE1 always achieved the best response, SIN-1 performed statistically significantly poorer irrespective of the dosage used. There were only a few side effects with no significant difference. SIN-1 is not a useful alternative to PGE1 in the treatment of erectile dysfunction.

Adult↗
PubMed1994

Pharmacological management of hypertension in paediatric patients. A comprehensive review of the efficacy, safety and dosage guidelines of the available agents.

The prevalence of hypertension in children, although lower than in adults, is still significant. An underlying cause is often identified in the younger patient, with essential hypertension accounting for the majority of cases in adolescents. The natural history of hypertension in childhood is still not well delineated. Previous Task Force recommendations are addressed to reflect current experience with the newer classes of agents, namely the angiotensin converting enzyme (ACE) inhibitors and the calcium channel blockers (CCBs) where either limited or no experience was previously available. In addition, the current treatment recommendations of Joint National Committee V (JNCV) are reflected in our discussion. The current drug classes are reviewed with respect to dosage guidelines, adverse effects and potential drug-drug interactions. The advantages and disadvantages of a tailored or individualised therapeutic approach as opposed to rigid stepped care therapy will be presented. Clearly, more long term data need to be obtained with respect to the safety and efficacy of the newer classes of drugs.

Adrenergic alpha-Agonists↗
PubMed1994

Drug interactions of H2-receptor antagonists.

Three drug interactions of nizatidine and of other antisecretory agents were studied comparatively. First, the effects of nizatidine, cimetidine and ranitidine on the dispositional kinetics of theophylline were evaluated in chronic obstructive pulmonary disease (COPD) patients. Second, the effect of magnesium/aluminium hydroxide on the relative bioavailability of nizatidine, famotidine, cimetidine and ranitidine was evaluated in healthy volunteers. Finally, the effects of nizatidine and omeprazole on the dispositional kinetics of phenytoin were evaluated in healthy volunteers. Only cimetidine altered the steady-state kinetics of oral theophylline, slowing theophylline clearance by 25%. Each of the H2-receptor antagonists exhibited a modest decline in relative bioavailability when ingested with antacid. Antacid ingestion decreased the bioavailability of famotidine, ranitidine and cimetidine by 20-25%, and the bioavailability of nizatidine by 12%. Each of these effects was statistically significant. Finally, it was found that neither omeprazole nor nizatidine affected the single dose kinetics of phenytoin.

Adolescent↗
PubMed1994

The rpa (receptor potential absent) visual mutant of the blowfly (Calliphora erythrocephala) is deficient in phospholipase C in the eye.

The rpa (receptor potential absent) mutation of the blowfly, Calliphora erythrocephala, reduces the light-evoked responses of photoreceptor cells and renders the fly blind. This phenotype is similar to the phenotype caused by norpA mutations in Drosophila which have been shown to occur within a gene encoding phospholipase C. In Western blots, norpA antiserum stains a protein in homogenates of wild-type Calliphora eye and head that is similar in molecular weight to the norpA protein. Very little staining of this protein is observed in similar homogenates of rpa mutant. Moreover, norpA antiserum strongly stains retina in immunohistochemical assays of wild-type adult head, but not in rpa mutant. Furthermore, eyes of rpa mutant have a reduced amount of phospholipase C activity compared to eye of wild-type Calliphora. These data suggest that the rpa mutation occurs in a phospholipase C gene of the blowfly that is homologous to the norpA gene of Drosophila.

Animals↗
PubMed1994

Cryptosporidium parvum in children with diarrhea in Mexico.

Using an anti-oocyst wall monoclonal antibody-based immunofluorescence assay, the presence of Cryptosporidium parvum was evaluated in children with diarrhea from rural areas (selected from a door-to-door community survey) and from urban areas (patients attending hospitals) in the State of Puebla, Mexico. Prevalences of 9.4% in a rural population (n = 85) and 29.6% in a hospital-based urban population (n = 81). There was no consistent correlation between water source and other environmental data and the presence of C. parvum in stools. It is concluded that C. parvum may be an important pathogen associated with diarrhea in this Mexican state.

Animals↗
PubMed1994

Isochromosome-formation in chromosome 9.

A new case of de novo isochromosome-formation in chromosome 9 associated with the translocation of long arm material of chromosome 9 onto chromosome 1 is described. The female patient is mentally retarded and shows only minor dysmorphisms. The cytogenetic investigation revealed a two-cell-line mosaicism with different isochromosomes of chromosome 9. In both cell lines, a translocation of 9qter-9q13 onto the short arm of chromosome 1 is observed.

Abnormalities, Multiple↗
PubMed1994

[Functional results and complications of the ileal neobladder in over 200 patients].

Between April 1986 and October 1992, a total of 229 patients with invasive bladder cancer underwent radical cystectomy and lower urinary tract reconstruction by means of the ileal neobladder. The perioperative mortality was 2.4%. Subsequently 10.5% of the patients suffered from early complications that led to relaparotomy and 3.8% of the patients had bowel occlusion. Significant late complications were urethro-ileal strictures (6.7%) and stenosis of the ureteral anastomosis (3.3%). Despite a very strict definition of continence, only 2 patients with a follow up of more than 2 years had an incontinence grade 3. Most (77%) of the patients in this collective were perfectly continent day and night, while 11.5% had only occasional spotting and wore pads to be on the safe side. In conclusion, the medium-term results are now available (average follow up 41 months) and show that the ileal neobladder is the treatment of choice for male patients after radical cystectomy for the treatment of invasive bladder cancer.

Adult↗
PubMed1993

Adenosine-induced suppression of synaptic responses and the initiation and expression of long-term potentiation in the CA1 region of the hippocampus.

The results of several previous studies have suggested that pretreatment with adenosine can block the induction of long-term potentiation (LTP), although other studies have found no effect of adenosine on the induction of LTP. The interaction of adenosine with the induction of LTP in the rat hippocampal slice was investigated. Inhibition of synaptic responses by adenosine either prior to or immediately after high-frequency or theta-burst stimulation did not affect LTP measured after washout of the adenosine. The only conditions under which adenosine blocked the development of LTP was when it was given 3-5 minutes prior to the stimulation train. To understand how it was possible to induce LTP, during the period 1-3 minutes following adenosine when synaptic responses were virtually eliminated, evoked responses during the 100 Hz stimulation train were recorded. Although synaptic responses to low-frequency stimulation were virtually eliminated by adenosine, they reappeared during high-frequency stimulation. These results suggest that although adenosine can depress synaptic responses, an increase in neurotransmission during a high-frequency train can partially overcome this effect of adenosine, and the hypothesis that adenosine can selectively block LTP is not supported.

Action Potentials↗
PubMed1993

Photodynamic activity of liposome-delivered Cd-texaphyrin using tumor-bearing nude mice.

Photodynamic effects in bladder-tumor bearing nude mice induced by a krypton ion laser (752.5 nm) after i.v. application of liposome-delivered cadmium texaphyrin were investigated. Cd-texaphyrin possesses strong absorption transitions in the far red spectral region (around 760 nm) and a high quantum efficiency of singlet oxygen production. No therapeutic effects were obtained using irradiation 24 hours after administration of the sensitizer, whereas phototreatment 2 hours after application led to significant tumor reduction. This corresponds well with studies on fluorophore-labeled liposomes indicating highest tumor accumulation 1-2 hours after administration. However, the induced cytotoxic effects were lower than those of HpD.

Animals↗
PubMed1993

Fibroblast growth factor complexed to the cytotoxin saporin is growth inhibitory but not cytotoxic for embryonal carcinoma cells.

Fibroblast growth factors (FGFs) have been implicated in a number of proliferative lesions, including malignant tumor growth and vascularization. As a result, cytotoxic agents that target cell surface FGF receptors are currently under investigation. Previous reports have shown that conjugation of basic FGF with the ribosome inactivator, saporin, results in a potent cytotoxin specific for cells bearing high-affinity FGF receptors. In this report, we have used this FGF receptor-dependent cytotoxin to study receptor interactions at the surface of embryonal carcinoma cells, which express low numbers of high-affinity FGF receptors. The growth of three embryonal carcinoma cell lines and one embryonic stem cell line was shown to be inhibited by bFGF-saporin, suggesting that these cells are able to bind and internalize FGF through high-affinity FGF receptors. In addition, we determined that the responses of these cells to bFGF-saporin are qualitatively different than the responses of CHO-KI cells, which also exhibit low numbers of high-affinity FGF receptors. Specifically, pretreatment with bFGF-saporin reduces the cloning efficiency of CHO-KI cells 8- to 10-fold, whereas bFGF-saporin has little or no effect on the cloning efficiency of embryonal carcinoma cells. This finding suggests that bFGF-saporin is cytotoxic for CHO-KI cells, but not for embryonal carcinoma cells. Thus, our findings argue strongly that other factors, in addition to high-affinity FGF receptor number, are important in determining sensitivity of cells to bFGF-saporin.

Animals↗