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Biomedical subjects

I Katz

Publications and source records attributed to I Katz.

At least 55 records · Page 3Linked to original sources
PubMed1991

Effect of low concentrations of ozone on inhaled allergen responses in asthmatic subjects.

The relation between inhalation of ambient concentrations of ozone and airway reactivity to inhaled allergens may be important in asthma, since both agents can produce inflammatory changes in the airways. Seven asthmatic patients (mean age 40 [SD 13] years), with seasonal symptoms of asthma and positive skin tests for ragweed or grass, took part in a study to investigate whether exposure to low concentrations of ozone potentiates the airway allergic response. The patients were studied during 4 separate weeks in the winter. In each week there were 3 study days: on days 1 and 3 methacholine challenges were carried out; and on day 2 the subject received one of four combined challenges in a single-blind design--air breathing followed by inhalation of allergen diluent (placebo); ozone followed by inhalation of allergen diluent; air followed by allergen; or ozone followed by allergen. The ozone concentration was 0.12 ppm during 1 h of tidal breathing at rest, and allergens were inhaled until the forced expiratory volume in 1 s (FEV1) had fallen by 15% (PC15). There were no significant differences in baseline FEV1 after exposure to ozone but PC15 was significantly reduced when allergen was preceded by ozone inhalation: the mean PC15 after air was 0.013 (SD 0.017) mg/ml compared with 0.0056 (0.0062) mg/ml after ozone (p = 0.042). Thus, low ozone concentrations, similar to those commonly occurring in urban areas, can increase the bronchial responsiveness to allergen in atopic asthmatic subjects. This effect does not seem to be the result of changes in baseline airway function.

Adult↗
PubMed1991

Subchondral bone in osteoarthritis.

To determine whether subchondral bone in osteoarthritis differs from that seen in normal human aging, osteoarthritic femoral heads removed for total hip arthroplasty were compared with normal age-matched and young autopsy controls. Standardized, 1-cm deep, weight-bearing and nonweight-bearing subchondral bone blocks, as well as cancellous core bone, 2-4 cm deep on the articular surface, were examined in each femoral head. Mineralization was assessed using density fractionation and chemical analysis, and compared to histomorphometry. In osteoarthritis, both weight-bearing and nonweight-bearing surface subchondral bone showed a lower degree of mineralization than age-matched and young controls. Histomorphometric analysis showed that subchondral bone thickness, as well as all osteoid parameters and eroded surfaces, were increased in osteoarthritic samples versus controls. Mineralization in the deep cancellous core bone increased with normal aging but underwent less change with osteoarthritis. Histomorphometry of the cancellous core showed that osteoid parameters, but not bone volume, were increased in osteoarthritis versus controls. In conclusion, osteoarthritis is associated with a thickening of the subchondral bone with an abnormally low mineralization pattern.

Aged↗
PubMed1991

Salmon calcitonin prevents cyclosporin-A-induced high turnover bone loss.

Cyclosporin-A (CsA) has greatly influenced the outcome of organ transplantation and has also been effective in the treatment of many autoimmune diseases. Unfortunately, it has deleterious effects on bone remodelling, causing a high turnover bone loss, with bone resorption exceeding bone formation. Salmon calcitonin (SCtn) has been shown to inhibit bone resorption in high turnover states such as Paget's disease and postmenopausal osteoporosis. In an attempt to attenuate the high turnover bone remodelling caused by CsA alone, we studied the bone mineral effects of CsA in combination with SCtn in male Sprague-Dawley rats. Group A (n = 20) received vehicle as control, group B (n = 20) received CsA (15 mg/kg BW) by daily gavage and SCtn vehicle sc, group C (n = 20) received SCtn (1.3 IU/kg BW) daily sc and CsA vehicle, and group D (n = 20) received a combination of CsA and Ctn daily, as described above. Rats were bled weekly for determination of circulating biochemical bone parameters. Eight rats from each group were killed on day 14 (short term), and the remaining rats were killed on day 28 (long term). Tibiae were removed for bone histomorphometry after death, which revealed a reduction of trabecular bone volume and an increase in osteoclast number induced by CsA alone. These changes were significantly attenuated by the combination of CsA and SCtn to resemble the histomorphometry of the control group. The inhibition of osteoclast number by SCtn is the most plausible mechanism by which the combination therapy attenuates the high turnover bone loss induced by CsA alone.

Animals↗
PubMed1991

Effect of sex hormones on human T cell activation by concanavalin A.

The effect of sex hormones on concanavalin A (Con A)-activated human T cells was studied. We show that neither 17 beta-estradiol (E2) nor progesterone, in concentrations of up to 10(-6) M, alters the proliferative response of peripheral-blood mononuclear cells (PBMC) of healthy postmenopausal women. Furthermore, the hormones had no effect on the composition of T cell populations and on the expression of activation markers. We extended our study to a unique T cell population that is characterized by the ability to form rosettes with human erythrocytes, following Con A activation (designated autorosette-forming cells; ARFC) and known to manifest suppressive activity. Indeed, the in vitro addition of E2 (neither progesterone nor testosterone) to Con A-stimulated PBMC brought an about 2- to 4-fold increase in the frequency of ARFC. Tamoxifen, an antiestrogen drug, reduced the frequency of estrogen-stimulated ARFC to the original low level. Furthermore, the inhibitory effect of growth medium from ARFC cultures originally stimulated with Con A + E2 was found to be higher than that of ARFC cultures originally stimulated with Con A alone.

Concanavalin A↗
PubMed1990

Adult xanthogranulomatosis associated with abnormal plasma apolipoprotein levels.

A case of adult xanthogranulomatosis was investigated in depth for lipid abnormalities. The xanthogranulomatous lesion was shown to be composed primarily of cholesterol esters and triglycerides. Fasting plasma lipid levels and lipoprotein concentrations were within normal limits. Plasma lipoprotein electrophoresis and immunoelectrophoresis demonstrated normal high-density lipoprotein (HDL) and low-density lipoprotein mobilities. Polyacrylamide-gel isoelectric-focusing electrophoresis revealed increased levels of very-low-density apolipoprotein (apo) E, especially apo E-III. In the HDL fraction, apo-C-III and apo-E levels were both found to be slightly elevated. These findings might imply a causal relationship between the abnormal plasma apolipoprotein levels and the xanthogranulomatous disease.

Adult↗
PubMed1990

Kaposi's sarcoma: retrospective study of 67 cases with the classical form.

The records of 67 Israeli patients with classical Kaposi's sarcoma treated at Rambam Medical Center were analyzed retrospectively for clinical and laboratory data. As expected, all except 1 patient were of Jewish origin. There was a male predominance with a ratio of 2.2:1. The age of onset was mostly during the 5th to 7th decades of life. The course of the disease was usually slow and indolent. As has been already noted, we found a higher frequency of diabetes mellitus (16.4%). Although a high frequency of second primary malignancy was seen in our patients, this was less so than that described in an American series, 15% as compared to 37%, respectively. The most frequent second malignancy was that of the lymphoreticular system. No serologic evidence for an association with types of herpes virus infection has been found. No alterations in humoral and cellular immunity were demonstrated. These data show similar clinical findings with those described in other series, besides the lower frequency of a second primary malignancy. Some discordance with that described before concerning the relationship with cytomegalovirus infection and T cells subsets was also noted.

Adult↗
PubMed1990

Do patients with obstructive sleep apnea have thick necks?

During physical examination of patients with suspected obstructive sleep apnea (OSA), a comment is frequently made that they appear to have a short and fat neck. To confirm this subjective impression by objective measurements, we studied a group of 123 patients referred to us because of snoring and suspected OSA, all of whom had nocturnal polysomnography and measurements of external and internal neck circumference. The external neck circumference was measured at the level of the superior border of the cricothyroid cartilage. Internal neck circumferences were calculated from the measurements of pharyngeal, glottic, and tracheal areas obtained by the acoustic reflection technique. Internal pharyngeal circumference was further subdivided into the proximal, middle, and distal thirds. The acoustic technique also permitted us to measure the distance between the teeth and the glottic minimum, which reflects the length of the upper airway. Stepwise multiple linear regression analysis revealed that the apnea/hypopnea index (AHI) correlated only with the external neck circumference, the body mass index, and the internal circumference of the distal pharynx; these three variables accounted for 39% of the variability in AHI. We conclude that the external and internal neck circumferences and the degree of obesity are important predictors of sleep apnea; it is possible that obesity produces its effect via fat in the neck. We speculate that the static pharyngeal size modulated by the dynamic loading of the airway due to the weight of fatty tissue of the neck may contribute to the pathogenesis of OSA.

Adult↗
PubMed1990

An evaluation of flow-volume curves as a screening test for obstructive sleep apnea.

We examined flow-volume curves for their potential as screening tests for obstructive sleep apnea (OSA) in 401 patients referred for investigation of snoring. In all patients, we performed nocturnal polysomnography, maximum inspiratory and maximum expiratory flow-volume curves. The curves were examined for two features: 1) presence of flow oscillations (the "saw-tooth" sign), and 2) changes in their configuration that might suggest upper airway obstruction as documented by the expiratory/inspiratory flow ratios calculated at 50 and 75 percent of exhaled vital capacity (FR50 and FR25, respectively). Based on the results of nocturnal polysomnography, the patients were stratified according to severity into apnea groups, and the flow ratios and flow oscillations were compared among these groups. We found that neither the FR50 nor FR25 were significantly different among the groups. Inspiratory and expiratory flow oscillations were seen infrequently (32 patients) and tended to occur in patients with more severe sleep apnea. Neither the flow ratios nor the flow oscillations had good predictive values for snoring or sleep apnea. The sensitivity of the flow volume curve abnormalities ranged between 0 and 14 percent, but the specificity was high, ranging between 93 and 95 percent. We conclude that because of low sensitivity, flow-volume loops are not a useful screening test for the diagnosis of OSA in snoring patients.

Adult↗
PubMed1990

Mucociliary clearance from central airways in patients with excessive sputum production with and without primary ciliary dyskinesia.

Studies of mucociliary clearance were made on 17 patients with bronchiectasis and excessive sputum production. Tracheal mucus velocity was measured. Five patients with primary ciliary dysfunction and 12 who had no clinical evidence of this defect were studied. The mean (+/- SD) tracheal mucus velocity of the five patients with proved or presumptive primary ciliary dysfunction was 2.9 +/- 0.2 mm per minute and for the 12 patients without ciliary dysfunction, 7.9 +/- 1.4 mm per minute. (The previously determined rate for normals was 4.7 +/- 1.3 mm per minute.) In four of five patients with ciliary dysfunction, CBF was below 7.5 Hz while in the one patient of the 12 without ciliary dysfunction CBF was at the lower limit of normal values. Thus, mucociliary clearance responds to load, depends partly on CBF, and has a built-in control system and the means for compensating for ciliary dysfunction.

Adolescent↗
PubMed1989

Tracheal hysteresis in sleep apnea.

The collapsibility of pharyngeal walls, characteristic of patients with obstructive sleep apnea, likely results from reduced tone of the pharyngeal muscles. This reduction in the upper airway muscle tone may not end at the pharynx but may extend further distally, e.g., into the trachea. Because tracheal tone cannot be measured directly in conscious humans, we inferred the tone from the relative hysteresis of the tracheal area compared with the lung. Relative hysteresis was measured by plotting the cross-sectional area of a tracheal segment obtained by the acoustic reflection technique vs. lung volume. All measurements were performed during wakefulness. We found that in 42 patients with obstructive sleep apnea (apnea/hypopnea index greater than 10), relative hysteresis of the proximal trachea was predominantly clockwise, i.e., smaller than that of the lung parenchyma; in the 33 nonapneic patients (apnea/hypopnea index less than or equal to 10), it was predominantly counter-clockwise, i.e., larger than that of the lung parenchyma. For the distal trachea all patients, apneic and nonapneic, had similar, clockwise, relative hysteresis. We conclude that reduction in the upper airway muscle tone in patients with obstructive sleep apnea extends into the trachea.

Adolescent↗
PubMed1989

Maximal expiratory flow at FRC, adjusted for absolute lung volume: specific Vmax FRC.

Maximal expiratory flow-volume curves were recorded in 85 healthy subjects, aged from 18 to 78 years. The maximal expiratory flow was measured at 75, 50 and 25% of the vital capacity (VmaxVC), at 60 and 40% of the total lung capacity (VmaxTLC), and at the functional residual capacity level (VmaxFRC). The latter was adjusted for the lung volume at which it was measured. The new parameter was named specific VmaxFRC (SVmaxFRC) and expressed in s-1. Normal values and prediction formulas based on height, weight, age and sex were established. It was found that: (1) adjustment for lung volume narrowed the interindividual variability of SVmaxFRC from 47 to 37%; (2) did not diminish the influence of age (p less than 0.001); (3) erased the influence of height and VC; (4) reduced the correlation with FEV1 (p less than 0.05), and (5) unveiled a borderline correlation with specific conductance (p less than 0.05).

Adult↗
PubMed1989

Ciliary ultrastructure of respiratory and fallopian tube epithelium in a sterile woman with Kartagener's syndrome. A quantitative estimation.

Ciliary ultrastructure was studied and quantitatively estimated in a 27-year-old sterile woman suffering from complete KS. Ciliated epithelium was obtained from both nasal mucosa and a fallopian tube. Cilia from both locations were devoid of DA. Various MT abnormalities were found in 16 percent of respiratory epithelial and 21 percent of fallopian tube ciliary cross-sections. The abnormality related to radial spoke defect was frequently seen. The findings in the fallopian tubes were compared to three normal control cases. In these, DA were visible, and MT defects were mainly of excess or missing microtubules. The relevance of these findings to fertility is not clear.

Adult↗
PubMed1988

The psychiatric symptoms of Alzheimer's disease.

The authors used a semistructured interview administered to primary family caregivers to assess the prevalence and nature of psychiatric pathology in 175 well-diagnosed community-residing Alzheimer's disease patients. Symptoms that are indicative of depression in the cognitively intact were virtually ubiquitous in this demented population. A variety of psychotic features were also regularly reported. The implications of these findings for the recognition and treatment of reversible psychiatric impairment are discussed.

Aged↗
PubMed1988

Bronchoscopic evaluation of peripheral lung tumours.

The results obtained from fibreoptic bronchoscopy preformed under fluoroscopic guidance were evaluated in a prospective study of 71 consecutive patients with a peripheral lung lesion more than 2 cm in diameter on the chest radiograph. A peripheral lung lesion was defined as a lesion that was not seen within the bronchial tree at fibreoptic bronchoscopy. Small volume washings, bronchoalveolar lavage, transbronchial biopsy, and bronchial brushings were carried out and fluid or tissue was sent for cytological or histological examination as appropriate. Of the 71 patients, 51 were subsequently shown to have malignant disease. In 38 of the patients the diagnosis of malignancy was made by bronchoscopy, from histological specimens alone or in conjunction with cytological specimens in 33, from brushings alone in two, and from bronchoalveolar lavage fluid alone in three patients. There were no important complications. Thus fibreoptic bronchoscopy in conjunction with fluoroscopic screening appears to be an effective and safe method for the initial investigation of a peripheral lung lesion more than 2 cm in diameter.

Adult↗
PubMed1988

Relative hysteresis of the airways and lung parenchyma in normal subjects.

We evaluated the mechanical properties of the airways sequentially from the glottis toward the main bronchi in 10 normal subjects. Plots of airway cross-sectional area vs. lung volume, measured during inspiration and expiration, were used to determine the relative magnitude of the airways vs. parenchymal hysteresis. Airway cross-sectional area was measured by means of the acoustic reflection technique. We found that the hysteresis of the proximal part of the trachea was greater than that of the lung parenchyma, whereas the hysteresis of the distal trachea and subcarinal segments of the airways was smaller than that of the lung parenchyma. The transition zone between the proximal and the more distal airway properties occurred 8-26 cm distal to the glottis. This transition zone was reproducible in its location on repeated testing in each subject but varied among subjects. To the extent that relative hysteresis of the airways depends on bronchomotor tone, our findings suggest that the bronchomotor tone is inhomogeneous, being maximal at the proximal part of the trachea and gradually decreasing toward the more distal trachea and subcarinal airway segments.

Acoustics↗
PubMed1988

Therapy with nifedipine in asthma: a randomized double-blind crossover trial.

A randomized double-blind crossover trial with nifedipine (10 mg orally four times a day for 2 weeks) was carried out in 11 asthmatic patients. The analysis of the differences between the periods of running-in, placebo and nifedipine administration showed a mild improvement in symptom scores during the nifedipine period (2.8 +/- 1.5, 2.8 +/- 1.8 and 2.1 +/- 1.6, respectively; P less than 0.05). Drug intake and peak expiratory flow rates remained unchanged. This suggests that the drug did not influence the baseline bronchial tone, but might have attenuated some superimposed exacerbations due to unavoidable exposure to cold, effort or allergens. We conclude that the benefit of orally administered nifedipine in low doses has little value in the treatment of asthma.

Adult↗