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Biomedical subjects

I Doweck

Publications and source records attributed to I Doweck.

At least 19 recordsLinked to original sources
PubMed2001

Analysis of risk factors predictive of distant failure after targeted chemoradiation for advanced head and neck cancer.

BACKGROUND: Distant metastasis (DM) is the most common mode of recurrence among patients with advanced head and neck carcinoma treated with intra-arterial cisplatin and radiotherapy (RADPLAT). OBJECTIVE: To identify which patients are at greatest risk for DM and would benefit the most from new strategies designed to treat occult metastases. METHODS: Between 1993 and 1999, 250 patients with advanced head and neck cancer were treated by RADPLAT. Excluded from the analysis were 10 patients who either did not complete the protocol or were unavailable for follow-up and 39 patients with persistent disease or local recurrence. The incidence and the risk factors for DM in these patients were evaluated in a model that included the following factors: age, T and N classification, site of tumor, histologic grade, number (0, 1, or >1) and position (high vs low) of neck levels involved, and bilateral nodal disease. Multiple stepwise logistic regression was used for the analysis. RESULTS: In a univariate analysis, the following variables correlated to DM: N classification (P =.02), site of tumor (P =.01), lower neck nodes (P =.002), number of neck levels involved (P =.001), and bilateral nodal disease (P =.02). In a multivariate analysis, the most significant risk factors for DM were the number of neck levels involved and the site of the primary tumor (P<.001). The highest odds ratios for DM were among patients with multiple levels of nodal involvement (3.17) and patients with hypopharyngeal carcinoma (2.8). CONCLUSIONS: Patients with more than 1 level of clinical nodal involvement and patients with hypopharyngeal carcinoma have the highest risk of developing DM as the initial site of failure and would benefit most from treatment strategies that address occult distant disease.

Adult↗
PubMed2001

Inner ear decompression sickness in sport compressed-air diving.

OBJECTIVE: We report our experience over the past 12 years with recreational diving-related inner ear decompression sickness (IEDCS). STUDY DESIGN: Retrospective, consecutive case series. METHODS: Twenty-four divers, representing 29 cases of IEDCS, are presented with regard to evaluation, treatment, and follow-up. RESULTS: These 29 cases represent 26% of the severe decompression sickness (DCS) cases treated in that period. The patient group includes 22 divers who had a single event of IEDCS, one diver who had two events, and one with five repeated episodes. The cause of injury in 23 cases (79%) was violation of the decompression schedule. The mean time from surfacing to appearance of symptoms was 47 +/- 65 minutes. In 83%, symptoms appeared within 1 hour of ascent, in 97% within 2 hours, and in only one diver after 5.5 hours. Ten divers (34%) had pure vestibular involvement, 4 (14%) had cochlear insult alone, and 15 (52%) had combined vestibulo-cochlear injury. Except for one patient who had central as well as peripheral vestibulo-cochlear DCS, all the remaining patients had end organ involvement only, as demonstrated by physical examination and laboratory test results. Fifteen (52%) had isolated IEDCS, whereas 14 had additional symptoms of DCS. Twenty-six cases were treated by hyperbaric oxygenation with supplementary daily hyperbaric sessions. Of the 25 cases with vestibular injury and the 19 with cochlear damage, only 7 (28%) and 6 (32%), respectively, made a full recovery, whereas the others remained with residual damage. Of the 17 treated within 6 hours of symptom appearance, 9 (53%) were cured, compared with one of the 9 treated later (P <.05). CONCLUSIONS: IEDCS related to compressed-air recreational diving is more common than previously thought, and might occur even when no decompression schedule violation took place. Prompt diagnosis leading to the early commencement of hyperbaric oxygen recompression therapy is the key to complete recovery of cochlear and vestibular function.

Adult↗
PubMed2001

The effects of dimenhydrinate, cinnarizine and transdermal scopolamine on performance.

We assessed the influence of dimenhydrinate, cinnarizine and transdermal scopolamine on the ability to perform simulated naval crew tasks. The effect of single doses of dimenhydrinate, 100 mg, cinnarizine, 50 mg, and one transdermal scopolamine patch on psychomotor performance was evaluated using a double-blind, placebo-controlled, randomized, crossover design in three separate studies. A total of 60 young naval crew (20 for dimenhydrinate, 15 for cinnarizine and 25 for transdermal scopolamine) underwent a battery of computerized and paper and pencil performance tests, and filled out a questionnaire on side-effects and well-being self-assessment. Dimenhydrinate significantly impaired decision reaction time and auditory digit span. Most of the subjects who took dimenhydrinate also reported a subjective decrease in well-being and general performance abilities. Cinnarizine and transdermal scopolamine did not affect performance abilities. Cinnarizine was free of significant side-effects. Dry mouth was the only significant side-effect of transdermal scopolamine. These findings could be explained by the well-known sedative properties of dimenhydrinate and not by a specific effect on any particular cognitive or motor function. Our results suggest that dimenhydrinate, 100 mg, adversely affects psychomotor function, whereas single doses of cinnarizine, 50 mg, and transdermal scopolamine appear to be free of side-effects on performance and seem to be a preferable anti-seasickness drug for use by a naval crew.

Administration, Cutaneous↗
PubMed2000

The prognostic value of the tumour marker Cyfra 21-1 in carcinoma of head and neck and its role in early detection of recurrent disease.

This study examines a new tumour marker, Cyfra 21-1, as a prognostic marker in predicting the survival of H&N cancer patients, and its correlation with clinical outcome during prolonged follow up of these patients. The study included 67 patients with primary detection of carcinoma of H&N. The survival of these patients was evaluated in correlation with the disease stage and Cyfra 21-1 levels at initial diagnosis. 38 patients were followed clinically and with serial assays for at least 12 months, or until recurrence was diagnosed. Cyfra 21-1 levels were determined periodically, using an Elisa kit. Patients with Cyfra 21-1 < 1.5 ng ml(-1)had a higher survival rate compared to patients with Cyfra 21-1 > or = 1.5 ng ml(-1)(63% vs. 20%, respectively). The risk ratio of Ln(Cyfra 21-1) is 1.62 (P = 0.028). In a Cox regression model that included the disease stage and Ln(Cyfra 21-1), Ln(Cyfra 21-1) was preferred as the main parameter for predicting patients survival. In 83% of the 12 patients with recurrent or residual disease, Cyfra 21-1 was elevated before or during clinical detection of the recurrence. Cyfra 21-1 was found to be a prognostic marker for carcinoma of H&N, unrelated to the stage of the disease. Elevated levels of Cyfra 21-1 without clinical evidence of disease can be attributed to the marker's mean lead-time as compared to the clinical appearance of the disease.

Aged↗
PubMed1997

Alterations in R-R variability associated with experimental motion sickness.

Motion sickness is a complex integration of responses from multiple physiological systems. Whether the changes that occur during the time course of motion sickness are mediated by the sympathetic or parasympathetic systems is still controversial. The present study evaluates alterations in R-R variability during experimental motion sickness in motion sick and non-motion sick subjects. Ten motion sick subjects and 7 non-motion sick subjects participated in the study. Power spectrum analysis of R-R variation was conducted for all subjects 10 min before a brief vestibular disorientation test (BVDT), for 5-10 min of the test, and 10 min after the test. Subjects were also asked to report their symptoms during the test. The motion sick group showed a significant reduction in the power spectrum density of the R-R interval at the mid and high frequencies during the BVDT test period (BVDT), in comparison with the rest period (Rest). These changes probably indicate a decrease in parasympathetic activity during the time course of motion sickness. The non-motion sick group did not show significant differences at any of the frequencies during BVDT. Power spectrum analysis of the R-R interval provides an objective measure of the autonomic response to experimental motion sickness.

Adolescent↗
PubMed1996

Nonspecific vertigo with normal otoneurological examination. The role of vestibular laboratory tests.

Vestibular laboratory tests are not generally necessary in the diagnosis of patients with a clear description of vertigo accompanied by positive otoneurological examination findings. The purpose of the study was to investigate the role of conventional vestibular laboratory tests in the diagnosis of patients complaining of nonspecific vertigo, despite their having a documented normal otoneurological examination. The results of the standard electronystagmography (ENG) and sinusoidal harmonic acceleration (SHA) tests of 52 patients referred for ambulatory vestibular laboratory tests due to a nonspecific illusion of movement, but with a normal otoneurological examination, were reviewed. Abnormalities were found in the vestibular tests of 35 patients (67 per cent), 22 of whom (63 per cent) were finally diagnosed as having a unilateral peripheral vestibular lesion, and 13 (37 per cent) benign positional vertigo. These results suggest that a high percentage of patients with nonspecific vertigo and a normal otoneurological examination probably suffer from peripheral vestibular dysfunction, which can be objectively documented by the ENG and SHA tests.

Adult↗
PubMed1995

Cyfra 21-1. A new potential tumor marker for squamous cell carcinoma of head and neck.

OBJECTIVE: Evaluation of Cyfra 21-1 (cytokeratin fraction 21-1) in squamous cell carcinoma of the head and neck. DESIGN: Prospective study. PATIENTS: Serum Cyfra 21-1 concentration was measured in 250 samples from patients with squamous cell carcinoma of head and neck, patients with benign tumors of head and neck, healthy control subjects, and patients in remission from squamous cell carcinoma of head and neck. RESULTS: Cyfra 21-1 concentration was elevated in 60% of the new patients with squamous cell carcinoma but only in 8% of patients with benign tumors and 3.5% of the healthy controls. At a cutoff of 1.3 ng/mL, the sensitivity of the test was 60%, the specificity was 94%, positive predictive value was 75%, and negative predictive value was 89%. The marker levels tended to follow the clinical course of the disease and were useful for therapy monitoring. Cyfra 21-1 levels were in good correlation with the tumor stage expressed by the local (T) and the lymphatic spread (N) and were inversely correlated with histologic grade, eg, higher in poorly differentiated carcinoma than in well-differentiated squamous cell carcinoma. CONCLUSION: Cyfra 21-1 evaluation in head and neck squamous cell carcinoma is worthwhile for performance of an ample study that will prove and establish its routine use.

Adult↗
PubMed1994

Cinnarizine in the prophylaxis of seasickness: laboratory vestibular evaluation and sea study.

Cinnarizine was evaluated for the prevention of seasickness in a laboratory and sea study. The effects of 25 mg cinnarizine on the vestibulo-ocular reflex were investigated in 13 subjects. Significant reduction of the gain in response to sinusoidal oscillations at 0.02, 0.08, and 0.16 Hz (p < 0.05) and increased phase lead at 0.16 Hz (p < 0.01) were observed. The effect of 25 and 50 mg cinnarizine on seasickness severity was examined in 95 subjects during a voyage in rough seas. Seasickness symptoms were improved in 69% of the subjects by 50 mg cinnarizine versus 35% and 31% in the groups receiving 25 mg cinnarizine and placebo (p < 0.05 and p < 0.01, respectively). The percentage of vomiting protection provided by 50 mg cinnarizine was 63% (p < 0.05). We conclude that 50 mg cinnarizine is an effective drug for the prevention of seasickness. The reduction in vestibular sensitivity observed even after administration of 25 mg cinnarizine may explain the potency of cinnarizine in the prevention of seasickness.

Adolescent↗
PubMed1994

Effect of cinnarizine in the prevention of seasickness.

In a double-blind, placebo-controlled study, we evaluated the effect of two different doses of cinnarizine in the prevention of seasickness in very rough seas. We divided 95 healthy male subjects into 3 groups which received: cinnarizine 50 mg, cinnarizine 25 mg, and placebo. Seasickness susceptibility and severity were evaluated by a standard questionnaire concerning the subject's condition on previous voyages (seasickness susceptibility), and the subject's condition immediately after a 4-6-h voyage in very rough seas with 3.5 m waves (seasickness severity). Possible side effects of the drug were also evaluated by filling in a further questionnaire. Of the 31 subjects who received cinnarizine 50 mg, 65% felt better during the present voyage than on previous voyages, compared to 41% of the 32 subjects who received cinnarizine 25 mg and 31% of the 32 who received placebo. A significant difference (p < 0.05) was found between the cinnarizine 50 mg and placebo groups, while cinnarizine 25 mg was no more effective than placebo. No notable side effects were found for any drug group. In conclusion, cinnarizine 50 mg was found to be effective in the prevention of seasickness in rough seas.

Adolescent↗
PubMed1994

Seasickness susceptibility, personality factors, and salivation.

The present study investigates the possible relationship between motion sickness susceptibility, personality factors and salivation. Personality factors, as evaluated by the Eysenck Personality Questionnaire, and salivary composition and flow were measured in a group of 29 subjects highly susceptible to seasickness and in a group of 25 non-susceptible subjects. The non-susceptible group had significantly higher psychoticism scores and significantly lower salivary amylase levels compared to the highly susceptible group. A significant positive correlation was found between psychoticism scores and the amount of the increase in salivary flow in response to gustatory stimulation. These results provide more data in support of a connection between motion sickness susceptibility, personality, and the autonomic nervous system.

Adolescent↗
PubMed1993

Vestibulo-ocular reflex in migraine patients: the effect of sodium valproate.

We studied vestibulo-ocular reflex measurements in a group of 12 patients suffering from migraine without aura and evaluated the effect of sodium valproate given as prophylactic migraine therapy. The study was randomized, double blind and placebo controlled, with a crossover design. The horizontal vestibulo-ocular reflex was evaluated by the Sinusoidal Harmonic Acceleration test at 0.01, 0.02, 0.04, 0.08 and 0.16 Hz using a computerized rotatory chair system. No abnormalities were found for the vestibulo-ocular reflex gain, phase and asymmetry at each of the frequencies examined during the placebo treatment. These normal vestibulo-ocular reflex measurements contrasted with the repeated complaints of dizziness, vertigo and unsteadiness reported by 7 patients (58%). Sodium valproate affected neither vestibulo-ocular responses nor vestibular complaints but was effective in reducing migraine attacks in 8 of the 12 patients. These results demonstrate that the low frequency vestibulo-ocular reflex measurements are normal in patients suffering from migraine without aura.

Adult↗
PubMed1992

Salivary secretion and seasickness susceptibility.

The salivary flow rate and composition of 2 groups of 31 subjects, one group at each extreme of the seasickness susceptibility scale, were compared. No significant differences were found between the two groups in flow rates and electrolyte concentrations of whole resting and stimulated saliva. Amylase activity and rate of secretion in resting saliva were significantly higher in subjects susceptible to seasickness as compared with nonsusceptible subjects. Also, the total protein rate of secretion in resting saliva was significantly higher in the susceptible group. The present findings could be explained in terms of higher sympathetic tone in subjects susceptible to seasickness, and salivary amylase levels might be recommended as an additional parameter in the evaluation of seasickness susceptibility.

Adult↗
PubMed1991

Recurrent classic migraine attacks following transdermal scopolamine intoxication.

A 20 year old male naval crew-member suffering from sea sickness was treated with transdermal scopolamine (TS). After 5 months of continuous treatment, he developed scopolamine intoxication followed by the appearance of recurrent classic migraine attacks. He had never suffered from headache or migraine prior to TS intoxication. The migraine attacks comprised a prodrome of apathy, bad mood and loss of appetite lasting several hours. An aura of scintillating spots, left arm numbness and paresthesias lasting several minutes was followed by a severe throbbing unilateral headache with photophobia, sonophobia and nausea. After one year of repeated follow-up examination, he continued to suffer from the attacks once every 10 to 14 days, with no identified precipitating factors. We are not aware of similar cases in the medical literature. Although it is not possible to establish TS intoxication as a causal effect of the appearance of classic migraine in our patient, the temporal association and clinical course are very supportive of this assumption. Central nervous system neurotransmitter imbalance of cardiovascular alterations may possibly be implicated.

Administration, Cutaneous↗
PubMed1991

Pressure chamber tympanometry in diving candidates.

The currently recommended examination for diving fitness ascertains middle ear autoinflation ability only under surface pressure conditions. The purpose of our study was to document and quantify middle ear pressure equalization failure during simulated dives among diving candidates who had otherwise met the otologic criteria for diving fitness. Forty-two candidates for regular naval diving activity were included in the study. Tympanograms of both ears at 1 and 1.1 absolute atmospheres (ATA) were taken inside a pressure chamber with the subjects in two positions: seated and supine. At a pressure of 1 ATA, type A tympanograms were found in all 84 ears examined. At a pressure of 1.1 ATA, with subjects in the upright position, 19 (22.9%) of the ears had type C and 2 (2.4%) type B tympanograms, while with subjects recumbent during descent, 6 of the ears (7.2%) had type C and 7 (8.4%) type B. Our results suggest that successful autoinflation at surface ambient pressure does not necessarily reflect middle ear pressure equalization ability during descent in a dive.

Acoustic Impedance Tests↗
PubMed1991

Diving-related inner ear injuries.

Diving-related inner ear barotrauma (IEB) and inner ear decompression sickness (IEDS) most often result in permanent severe cochleovestibular deficits, unless immediate diagnosis is reached and the correct treatment is commenced early. Nine cases of sport-diving-induced inner ear injuries that were referred to the Israeli Naval Hyperbaric Institute between October 1987 and September 1989 are presented with regard to evaluation, treatment, and follow-up. The diagnosis was IEB in five divers and IEDS in four. Explorative tympanotomy was carried out with remarkable results in two patients with IEB, while the remaining three were relieved by bed rest alone. Three of the four IEDS patients were recompressed according to the extended US Navy Table 6 with good short-term results. The role of complete otoneurological evaluation in the decision-making process leading to the correct diagnosis and treatment is emphasized.

Adolescent↗
PubMedDate not supplied

The vestibulo-ocular reflex (VOR) under the influence of cinnarizine.

In a double-blind, placebo controlled, crossover study, we evaluated the effects of cinnarizine on the VOR of 55 healthy young subjects. VOR was evaluated by the Sinusoidal Harmonic Acceleration (SHA) test at frequencies of 0.01, 0.02, 0.04, 0.08 and 0.16 Hz. There was a reduction in VOR gain in 16 of the 20 SHA trials performed under the influence of cinnarizine alone (25 mg and 50 mg) and cinnarizine 25 mg in combination with 10 mg domperidone or 1 transdermal scopolamine patch. This decrease in VOR gain was significant in only a few SHA trials. Phase lead was not consistently affected by cinnarizine. No notable side effects were found for any of the drug groups. Our findings are in accord with the contention that increased resistance to seasickness produced either by drugs, or by the natural process of habituation to sea conditions, may be reflected by a decrease in VOR gain.

Adult↗