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Biomedical subjects

J Jordan

Publications and source records attributed to J Jordan.

At least 109 records · Page 6Linked to original sources
PubMed1997

Malignant vagotonia due to selective baroreflex failure.

Baroreflex failure is characterized by dramatic fluctuations of sympathetic activity and paroxysms of hypertension and tachycardia. In contrast, unopposed parasympathetic activity has not been described in patients with baroreflex failure because of concurrent parasympathetic denervation of the heart. We describe the unusual case of a patient with baroreflex failure in a setting of preserved parasympathetic control of HR manifesting episodes of severe bradycardia and asystole. Thus, parasympathetic control of the HR may be intact in occasional patients with baroreflex failure. Patients with this selective baroreflex failure require a unique therapeutic strategy for the control of disease manifestations.

Baroreflex↗
PubMed1997

Recombinant human interferon-beta in the treatment of condylomata acuminata.

The number of clinic consultations for condylomata acuminata (genital warts) has increased substantially during the last 30 years. Most infections produce benign lesions but a few types may be associated with cervical and penile cancers. Interferons (IFN) have shown antiviral properties to these infections and IFN-beta in particular has demonstrated a specific cytopathic effect in humans. A total of 124 patients with condylomata acuminata, the majority of whom had failed previous therapy, were treated intralesionally with either recombinant human interferon-beta la (r-hIFN-beta-1a) or placebo. Up to 6 lesions were treated in each patient, and injections were made 3 times per week for a total of 9 injections. The patients were then followed up for 3 months. Efficacy assessments at all time points (day 19, week 6 and month 3) showed a clear advantage for the r-hIFN-beta-1a interferon-beta treatment. Patients receiving r-hIFN-beta-1a showed a greater proportion of treatment success in terms of the complete or partial reduction (at least 50%) of the total area of the treated lesions. The treatment was also well tolerated. Headache, flu-like symptoms and asthenia were more common in patients receiving r-hIFN-beta-1a, but these adverse events were generally mild in severity and rarely led to patient withdrawal. It was concluded that r-hIFN-beta-1a has good efficacy in condylomata acuminata, and therefore presents a useful therapeutic alternative in this hard-to-treat condition.

Adult↗
PubMed1997

The physiological conundrum of hyperadrenergic orthostatic intolerance.

Orthostatic hypotension is a well-recognized medical problem in patients whose blood pressure falls dramatically with standing. Much less recognized is the syndrome of orthostatic intolerance. In patients with orthostatic intolerance, there are symptoms evoked by standing, but little actual fall in blood pressure. On the other hand, orthostatic intolerance patients frequently have a brisk tachycardia on standing. It has recently been recognized that many such individuals have a mild dysautonomia which may be brought on by conditions such as an antecedent viral illness, a rheumatologic disorder, or surgery/anesthesia. Recent studies of the hyperadrenergic (elevated plasma norepinephrine) subgroup of orthostatic intolerance is documenting a clinical spectrum including attenuated plasma renin activity and aldosterone, reduced supine blood volume coupled with dynamic orthostatic hypovolemia, elevated plasma norepinephrine and epinephrine, impaired clearance of norepinephrine from the circulation and evidence of partial dysautonomia. The emergence of partial dysautonomia as an important mechanism of orthostatic intolerance may lead to a substantial alteration in therapeutic approach.

Autonomic Nervous System↗
PubMed1997

Effects of substituting dietary soybean protein and oil for milk protein and fat in subjects with hypercholesterolemia.

OBJECTIVES: To determine whether, in individuals with hypercholesterolemia, substituting dietary soybean products for cows' milk products improves the plasma lipid profile and whether any change in the profile is due partially to soy oil. DESIGN: Randomized 3-treatment crossover trial. SETTING: Family practice clinics and an outpatient clinic in London, Ont. PARTICIPANTS: Seventeen healthy men and 17 healthy women with elevated plasma levels of total and low-density-lipoprotein (LDL) cholesterol and with normal plasma levels of triglycerides. INTERVENTIONS: Participants incorporated into their normal diet either 2% cows' milk products, soybean products or a combination of skim milk products and soy oil, each over period of 4 weeks, with 22-week wash-out periods. Plasma lipid profile, blood pressure and body weight were assessed after each dietary and wash-out period. OUTCOME MEASURES: Plasma levels of total and lipoprotein cholesterol, plasma levels of triglycerides, apolipoprotein B and A1 levels, blood pressure and plasma lipid peroxidation. RESULTS: The change in diet had no effect on body mass index, levels of apolipoproteins B and A1 and most plasma lipids. During the soybean period, the subjects' mean level of high-density-lipoprotein (HDL) cholesterol increased 9% (p < 0.04) and their mean LDL/HDL cholesterol ratio decreased 14% (p < 0.007). These effects were less pronounced during the skim milk/soy oil period. In the 24 subjects with the highest initial LDL cholesterol level and LDL/HDL cholesterol ratio, the mean LDL cholesterol level decreased 11% after the soybean period. In all subjects, changes in the LDL/HDL cholesterol ratio induced by a soybean diet were negatively correlated with the initial LDL/HDL cholesterol ratio and positively correlated with the initial HDL cholesterol level. CONCLUSIONS: In people with hypercholesterolemia, the plasma lipid profile improved after treatment with a soybean-product diet, and this improvement was partially due to soy oil. The degree of responsiveness was associated with initial risk factors for coronary artery disease.

Adult↗
PubMed1997

Knee pain and knee osteoarthritis severity in self-reported task specific disability: the Johnston County Osteoarthritis Project.

OBJECTIVE: To evaluate the contributions of radiographic knee osteoarthritis (OA) and knee pain severity to self-reported disability performing upper and lower extremity tasks in a rural, population based sample. METHODS: Data from 1192 African-American and Caucasian participants in the Johnston County Osteoarthritis Project were analyzed with multiple logistic regression to examine the roles of Kellgren-Lawrence radiographic knee OA grade and knee pain severity in self-reported difficulty performing 20 activities of the Health Assessment Questionnaire. Potential confounders included age, sex, race, marital status, education, and body mass index. RESULTS: Forty-three percent reported difficulty performing at least one task. Mild knee pain was independently associated with difficulty performing 16 upper and lower extremity tasks, and moderate/severe knee pain with all 20 tasks, with little change after adjustment (p < 0.0001). In contrast, mild radiographic knee OA was associated with difficulty in only 4 mobility and transfer tasks: climbing 5 steps, taking a tub bath, getting in/out of a car, and performing chores. Moderate/severe radiographic knee OA was associated with difficulty in 17 of 20 tasks (in 10 of 17, p < 0.0001), except lifting a cup, opening car doors, and turning faucets. However, no associations between radiographic knee OA and difficulty were statistically significant after adjustment for knee pain and the above factors. CONCLUSION: Knee pain severity was the strongest risk factor for self-reported difficulty performing tasks of upper and lower extremity function. Future studies of disability should include data on knee pain severity.

Activities of Daily Living↗
PubMed1997

[Dilemas in the evaluation of post-radiation lesions of the larynx].

The authors analyse the post-radiation lesions in larynx taking into consideration the cases of coexistence with residual or recurrent tumour. They underline the difficulties in obtaining a true picture of the condition of the larynx on the basis of histopathological examination. In a number of cases repeated histopathological examinations delayed the surgical treatment and thus caused in some them that the patient's chance to be cured was lost. The authors characterise clinical symptoms with strongly suggest the presence of tumour in those cases.

Adult↗
PubMed1996

Mammalian cells resistant to tumor suppressor genes.

Expression of p53 causes growth arrest or apoptosis in many normal and neoplastic cell types, but the relationship between these two effects has remained obscure. To begin to dissect the underlying mechanisms at a genetic level, we have generated mutant cells resistant to the action of wild-type p53. Rat embryo fibroblasts transformed with ras and a temperature-sensitive p53 (tsp53(135val)) gene were chemically mutagenized and selected for growth at a temperature at which p53 adopts a wild-type conformation (31.5 degrees C). Clones that grew exponentially at 31.5 degrees C were selected. Cell fusion experiments demonstrated that the mutations conferring resistance to p53-mediated growth arrest were dominant. The mutagenized clones were resistant not only to p53-mediated growth arrest, but also to the apoptosis induced by E1A in conjunction with p53, and partially resistant to the retinoblastoma tumor suppressor, pRB. The results suggest that a single downstream pathway can control the induction of growth arrest and apoptosis, and that both p53 and RB function through this pathway.

Adenovirus E1A Proteins↗
PubMed1996

Phosphatase inhibitors--III. Benzylaminophosphonic acids as potent inhibitors of human prostatic acid phosphatase.

Further investigation of the structural requirements of a series of benzylphosphonic acid inhibitors of human prostatic acid phosphatase has led to the highly potent series of alpha-aminobenzylphosphonic acids. The alpha-benzylaminobenzylphosphonic acid, with an IC50 = 4 nM, exhibited a 3500-fold improvement in potency over the carbon analogue, alpha-phenylethyl. The enhanced potency may be due to a combination of four favorable interactions including those with the phosphate binding region, the presence the hydrophobic moieties of the benzylamino and phenylphosphonic acid, and a rigid conformer produced by an internal salt bridge between the phosphonate and the alpha-amino group. Replacement of the phosphonic acid moiety with a phosphinic or carboxylic acid as well as deletion of the benzyl substitution of the alpha-amino group led to great reductions in potency.

Acid Phosphatase↗
PubMed1996

Effect of phenobarbital pretreatment on the pharmacokinetics and metabolism of diltiazem in rats.

In order to study the effect of cytochrome P-450 isozyme induction on the pharmacokinetics and metabolism of diltiazem (DTZ), male Sprague-Dawley rats weighing 300-600 g were randomly assigned to two groups. The enzyme induction group (n = 4) received phenobarbital 60 mg/kg i.p. once daily for 4 days, whereas the control group (n = 6) received normal saline for the same duration. Each rat then received a single oral dose of DTZ in solution (20 mg/kg). Blood samples (0.5 ml) were collected from each rat via an implanted polyethylene catheter (0.040" i.d.) in the right carotid artery at 0 (just before dosing), 0.25, 0.5, 1,2,3,4,6,8 and 10 h post-dose. Arterial plasma concentrations of DTZ and its metabolites M(A), M1, M2, M4 and M6 were determined by HPLC. Pharmacokinetics parameters were calculated using non-linear regression. The results showed that both mean Cmax and AUC of DTZ were lower (871.6 vs 79.8 ng/ml; 1171 vs 101.9 ng-h/ml), but the mean Cmax of the primary metabolites M1 and M(A) was higher after phenobarbital (M1 413.0 vs 648.9 ng/ml; M(A) 683.0 vs 814.8 ng/ml). The highest increase was seen in the mean Cmax and AUC of the secondary metabolite M2 (837.5 vs 2585.7 ng/ml; 3312.1 vs 13156.5 ng-h/ml). In contrast, plasma concentrations of the O-desmethylated metabolites M4 and M6 did not increase after phenobarbital. These results suggest that both deacetylation and N-demethylation of DTZ in rats are catalyzed by drug metabolizing enzymes inducible by phenobarbital.

Animals↗
PubMed1996

[Hyperbaric oxygen therapy in case of the neck diffuse phlegmon with very hard clinical course].

A case of 56 year old woman, diabetic (non-diagnosed before), suffering from diffuse phlegmon of the neck and acute submucosal laryngitis as a peritonsillar abscess complication is presented. Tracheotomy, abscess tonsillectomy with evacuation of peritonsillar abscess and extensive skin incisions of the neck with separation of tissue layers followed by drainage were performed at the beginning of hospitalization. This was regarded as responsible for stopping the violent development of the disease and saving the life of patient. Pathological bacteria were Streptococci (anaerobic and aerobic). Apart from the application of antibiotics (piperacyl, amikin, metronidazole) the patient was treated by hyperbaric oxygen (pressure 2,5 ata, one hour per day, on 6-9 day of treatment). Furthermore she was treated with oxygen applied through the tracheotomy tube during 5 days. In the authors' opinion the early performance of surgical procedure is necessary in the phlegmon of the neck as in the presented case. It is to be remembered, that these patients may suffer from other diseases like diabetes, non-diagnosed earlier. It has been noticed that significant improvement may be obtained by using the hyperbaric oxygen in the treatment of such cases.

Abscess↗
PubMed1996

[Complications of the digestive tract in patients after laryngectomy].

The authors describe the case of six patients who after having undergone laryngectomy suffered from complications affecting digestive tract. One of the patients contracted aerophagy and in the case of five other patients occurred bleeding from the upper digestive tract. Four of the letter five patients had perforation of the gastric ulcer; three of them were treated surgically (in two cases by partial resection of the stomach, in one by ligation of the vessels in ulceration area) and in one case the conservative treatment was applied. All four above patients were completely cured of neoplasmatic illness such and the complications. In the fifth case developed a multiple ulceration of the esophageal wall and its perforation. The patient died as a result of massive and repeated bleeding, despite application of thoracosurgical treatment. In the sixth case, of the patient with aerophagy, the applied treatment was conservative.

Adult↗
PubMed1995

Fatal acute pancreatitis caused by valproic acid.

We describe a case of a 31-year-old woman with cerebral palsy who developed fatal acute hemorrhagic pancreatitis while being treated with valproic acid to control her seizure activity. Acute pancreatitis is usually due to alcohol ingestion or biliary tract disease, and unusual causes include trauma, metabolic diseases, or drugs. Valproic acid is considered a safe drug, although rare cases of severe toxicity such as hepatitis and acute pancreatitis, including two fatalities, have been reported. Our review of the literature revealed that most patients who developed acute pancreatitis had serum levels of the drug within the therapeutic range, and most of the cases occurred either secondary to a recent increase in the dose or to initiation of treatment. It also appeared that the fatalities occurred due to a delayed diagnosis of acute pancreatitis, either resulting from an unsuspected diagnosis or to the deteriorated mental status of the patients receiving the drug, which precluded their ability to elaborate symptomatology. We believe that early diagnosis and withdrawal of the drug are significant factors determining the course of valproic-acid-associated pancreatitis.

Acute Disease↗
PubMed1995

Expression of human copper/zinc-superoxide dismutase inhibits the death of rat sympathetic neurons caused by withdrawal of nerve growth factor.

Rat superior cervical ganglion neurons require the presence of nerve growth factor (NGF) to develop and survive in culture. If NGF is removed from the culture medium, then the neurons die of programmed cell death. We investigated the potential role of Ca2+ and reactive oxygen species in this process. We found that overexpression of human wild-type copper/zinc-superoxide dismutase in cultured superior cervical ganglion neurons, using an adenovirus-based vector, substantially protected the cells from the effects of NGF withdrawal, although overexpression of the Ca(2+)-binding protein calbindin D28k or the enzyme beta-galactosidase did not. We also observed that treatment of the cells with the cytokine transforming growth factor-beta 1, which has been shown to protect neurons against oxidative injury, delayed cell death produced by NGF withdrawal. These data suggest a role for reactive oxygen species in triggering programmed cell death of rat sympathetic neurons upon growth factor withdrawal.

Animals↗