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Biomedical subjects

I Katz

Publications and source records attributed to I Katz.

At least 19 recordsLinked to original sources
PubMed1992

Malignant melanomas with histologic diameters less than 6 mm.

BACKGROUND: Malignant melanomas (MMs) with a small diameter (less than 6 mm) are rarely removed surgically; therefore there is a need for more data to characterize them. OBJECTIVE: The purpose of this study was to further elucidate the clinical and histopathologic features of small melanomas. METHODS: The greatest diameters of 112 consecutively submitted MMs were measured histologically. Those lesions with diameters of less than 6 mm were further studied clinically and histopathologically. RESULTS: Four MMs (3.5%) were found to have small histologic diameters. Their clinical features differed from the classic clinical ABCD's, although their histopathologic features resembled those of large MMs. Their depth of dermal invasion was relatively superficial, and their clinical outcome was favorable. CONCLUSION: Histopathologically, small MMs tend to resemble large MMs, but clinically they may require other diagnostic criteria. Because they tend to show a relatively superficial depth of invasion, their increased recognition and removal may have an impact on overall mortality from MM.

Adult↗
PubMed1992

Cutaneous graft-versus-host-like reaction after paternal lymphocyte immunization for prevention of recurrent abortion.

We have presented an immunocompetent patient who, after paternal lymphocyte immunization, developed a GVH-like skin reaction; she recovered spontaneously. This complication is rarely seen. This was the only case observed in our series of over 70 patients immunized. A similar phenomenon was not reported in a larger series by Carp and colleagues (1). However, the case deserves special attention because this reaction can be life-threatening. Therefore, we suggest that paternal lymphocyte immunization should be recommended only for those patients who have undergone a thorough work-up and in whom all causes, other than immunological, for recurrent abortion have been excluded. Even then, this treatment should be given with utmost caution. In view of the above described complication, we believe that more data are still required to justify offering such a treatment modality on a routine basis.

Abortion, Habitual↗
PubMed1992

Use of analytically defined estimates of aerosol respirable fraction to predict lung deposition patterns.

Analytical estimates of the respirable fractions on inhaled pharmaceutical aerosols are obtained by inertial sampling techniques. The respirable fraction may be defined as that portion of the particle size distribution less than a designated diameter. The diameter size below which particles were considered respirable in these studies was 6.4 microns. In clinical practice, a variety of particle size distributions may be related to a single respirable fraction. Herein, three respirable fractions were each defined by six particle size distributions. The deposition patterns of aerosols exhibiting these particle size characteristics were examined in a mathematical model. The analytically defined respirable fractions were compared with predicted lung deposition values. Under clearly defined breathing conditions, there is a correlation between the nominal respirable fraction and deposition. However, it was concluded that the variations which occur in breathing parameters within patient populations may not allow a single analytically derived respirable fraction to be appropriate for all individual subjects.

Adult↗
PubMed1992

17 beta-estradiol prevents osteopenia in the oophorectomized rat treated with cyclosporin-A.

Cyclosporin-A (CsA) administered to the oophorectomized rat exaggerates the high turnover osteopenia associated with oophorectomy alone. This study investigated whether 17 beta-estradiol replacement could influence the development of osteopenia in the oophorectomized rat treated with CsA. Ninety female Sprague-Dawley rats, approximately 300 g in weight, were divided into 6 groups of 15 each and treated according to the following protocol: group A were sham operated (control), group B underwent oophorectomy (Ox), group C underwent Ox and received CsA (15 mg/kg, by daily gavage) for 28 days (Ox and CsA), group D underwent Ox and received CsA and a 0.1 mg 17 beta-estradiol pellet (EP) implanted sc (Ox, CsA, and EP), group E underwent Ox and received EP (Ox and EP), and group F, which was intact and nonoperated, received CsA (CsA). Rats were weighed and bled on days -7, 0, 7, 14, 21, and 28 for measurement of blood ionized calcium, bone Gla protein (BGP), 17 beta-estradiol, and PTH. Bone histomorphometry was determined after double tetracycline labeling. On day 28, serum 17 beta-estradiol was undetectable in groups B (Ox) and C (Ox and CsA), and similar to group A (control) in groups D (Ox, CsA, and EP), E (Ox and EP), and F (CsA). Oophorectomy resulted in a significant gain in weight in groups B (Ox) and C (Ox and CsA), which was prevented by 17 beta-estradiol in groups D (Ox, CsA, and EP) and E (Ox and EP). On day 28, serum BGP levels were higher in groups B (Ox; 73.58 +/- 3.63 ng/ml), C (Ox and CsA; 85.05 +/- 9.88), and F (CsA; 81.35 +/- 3.4) compared to group A (control; 46.07 +/- 5.52; P less than 0.05), while 17 beta-estradiol in groups D (Ox, CsA, and EP; 38.65 +/- 2.85) and E (Ox and EP; 41.89 +/- 1.89) prevented this rise (P = 0.01). BGP levels in group C (Ox and CsA) were higher on days 14 and 21 compared to group B (Ox). Groups D (Ox, CsA, and EP) and E (Ox and EP) had elevated blood ionized calcium levels from day 7 onward. Serum PTH levels were unchanged. Histomorphometric analyses of tibial metaphyses revealed increased parameters of bone formation and resorption, with significant loss of bone volume, in groups B (Ox; 12.03 +/- 1.40%) and C (Ox and CsA; 11.43 +/- 2.20) vs. group A (control; 24.36 +/- 2.37; P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
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↗